1 /*
   2  * Copyright (c) 1999, 2026, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.tools.javac.comp;
  27 
  28 import java.util.*;
  29 import java.util.function.BiConsumer;
  30 import java.util.function.Consumer;
  31 import java.util.stream.Stream;
  32 
  33 import javax.lang.model.element.ElementKind;
  34 import javax.tools.JavaFileObject;
  35 
  36 import com.sun.source.tree.CaseTree;
  37 import com.sun.source.tree.IdentifierTree;
  38 import com.sun.source.tree.MemberReferenceTree.ReferenceMode;
  39 import com.sun.source.tree.MemberSelectTree;
  40 import com.sun.source.tree.TreeVisitor;
  41 import com.sun.source.util.SimpleTreeVisitor;
  42 import com.sun.tools.javac.code.*;
  43 import com.sun.tools.javac.code.Lint.LintCategory;
  44 import com.sun.tools.javac.code.LintMapper;
  45 import com.sun.tools.javac.code.Scope.WriteableScope;
  46 import com.sun.tools.javac.code.Source.Feature;
  47 import com.sun.tools.javac.code.Symbol.*;
  48 import com.sun.tools.javac.code.Type.*;
  49 import com.sun.tools.javac.code.Types.FunctionDescriptorLookupError;
  50 import com.sun.tools.javac.comp.ArgumentAttr.LocalCacheContext;
  51 import com.sun.tools.javac.comp.Check.CheckContext;
  52 import com.sun.tools.javac.comp.DeferredAttr.AttrMode;
  53 import com.sun.tools.javac.comp.MatchBindingsComputer.MatchBindings;
  54 import com.sun.tools.javac.jvm.*;
  55 
  56 import static com.sun.tools.javac.resources.CompilerProperties.Fragments.Diamond;
  57 import static com.sun.tools.javac.resources.CompilerProperties.Fragments.DiamondInvalidArg;
  58 import static com.sun.tools.javac.resources.CompilerProperties.Fragments.DiamondInvalidArgs;
  59 
  60 import com.sun.tools.javac.resources.CompilerProperties.Errors;
  61 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
  62 import com.sun.tools.javac.resources.CompilerProperties.LintWarnings;
  63 import com.sun.tools.javac.resources.CompilerProperties.Warnings;
  64 import com.sun.tools.javac.tree.*;
  65 import com.sun.tools.javac.tree.JCTree.*;
  66 import com.sun.tools.javac.tree.JCTree.JCPolyExpression.*;
  67 import com.sun.tools.javac.util.*;
  68 import com.sun.tools.javac.util.DefinedBy.Api;
  69 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
  70 import com.sun.tools.javac.util.JCDiagnostic.Error;
  71 import com.sun.tools.javac.util.JCDiagnostic.Fragment;
  72 import com.sun.tools.javac.util.JCDiagnostic.Warning;
  73 import com.sun.tools.javac.util.List;
  74 
  75 import static com.sun.tools.javac.code.Flags.*;
  76 import static com.sun.tools.javac.code.Flags.ANNOTATION;
  77 import static com.sun.tools.javac.code.Flags.BLOCK;
  78 import static com.sun.tools.javac.code.Kinds.*;
  79 import static com.sun.tools.javac.code.Kinds.Kind.*;
  80 import static com.sun.tools.javac.code.TypeTag.*;
  81 import static com.sun.tools.javac.code.TypeTag.WILDCARD;
  82 import static com.sun.tools.javac.tree.JCTree.Tag.*;
  83 
  84 /** This is the main context-dependent analysis phase in GJC. It
  85  *  encompasses name resolution, type checking and constant folding as
  86  *  subtasks. Some subtasks involve auxiliary classes.
  87  *  @see Check
  88  *  @see Resolve
  89  *  @see ConstFold
  90  *  @see Infer
  91  *
  92  *  <p><b>This is NOT part of any supported API.
  93  *  If you write code that depends on this, you do so at your own risk.
  94  *  This code and its internal interfaces are subject to change or
  95  *  deletion without notice.</b>
  96  */
  97 public class Attr extends JCTree.Visitor {
  98     protected static final Context.Key<Attr> attrKey = new Context.Key<>();
  99 
 100     final Names names;
 101     final Log log;
 102     final LintMapper lintMapper;
 103     final Symtab syms;
 104     final Resolve rs;
 105     final Operators operators;
 106     final Infer infer;
 107     final Analyzer analyzer;
 108     final DeferredAttr deferredAttr;
 109     final Check chk;
 110     final Flow flow;
 111     final MemberEnter memberEnter;
 112     final TypeEnter typeEnter;
 113     final TreeMaker make;
 114     final ConstFold cfolder;
 115     final Enter enter;
 116     final Target target;
 117     final Types types;
 118     final Preview preview;
 119     final JCDiagnostic.Factory diags;
 120     final TypeAnnotations typeAnnotations;
 121     final TypeEnvs typeEnvs;
 122     final Dependencies dependencies;
 123     final Annotate annotate;
 124     final ArgumentAttr argumentAttr;
 125     final MatchBindingsComputer matchBindingsComputer;
 126     final AttrRecover attrRecover;
 127     final LocalProxyVarsGen localProxyVarsGen;
 128     final boolean captureMRefReturnType;
 129 
 130     public static Attr instance(Context context) {
 131         Attr instance = context.get(attrKey);
 132         if (instance == null)
 133             instance = new Attr(context);
 134         return instance;
 135     }
 136 
 137     @SuppressWarnings("this-escape")
 138     protected Attr(Context context) {
 139         context.put(attrKey, this);
 140 
 141         names = Names.instance(context);
 142         log = Log.instance(context);
 143         lintMapper = LintMapper.instance(context);
 144         syms = Symtab.instance(context);
 145         rs = Resolve.instance(context);
 146         operators = Operators.instance(context);
 147         chk = Check.instance(context);
 148         flow = Flow.instance(context);
 149         memberEnter = MemberEnter.instance(context);
 150         typeEnter = TypeEnter.instance(context);
 151         make = TreeMaker.instance(context);
 152         enter = Enter.instance(context);
 153         infer = Infer.instance(context);
 154         analyzer = Analyzer.instance(context);
 155         deferredAttr = DeferredAttr.instance(context);
 156         cfolder = ConstFold.instance(context);
 157         target = Target.instance(context);
 158         types = Types.instance(context);
 159         preview = Preview.instance(context);
 160         diags = JCDiagnostic.Factory.instance(context);
 161         annotate = Annotate.instance(context);
 162         typeAnnotations = TypeAnnotations.instance(context);
 163         typeEnvs = TypeEnvs.instance(context);
 164         dependencies = Dependencies.instance(context);
 165         argumentAttr = ArgumentAttr.instance(context);
 166         matchBindingsComputer = MatchBindingsComputer.instance(context);
 167         attrRecover = AttrRecover.instance(context);
 168         localProxyVarsGen = LocalProxyVarsGen.instance(context);
 169 
 170         Options options = Options.instance(context);
 171 
 172         Source source = Source.instance(context);
 173         allowReifiableTypesInInstanceof = Feature.REIFIABLE_TYPES_INSTANCEOF.allowedInSource(source);
 174         allowRecords = Feature.RECORDS.allowedInSource(source);
 175         allowPatternSwitch = (preview.isEnabled() || !preview.isPreview(Feature.PATTERN_SWITCH)) &&
 176                              Feature.PATTERN_SWITCH.allowedInSource(source);
 177         allowUnconditionalPatternsInstanceOf =
 178                              Feature.UNCONDITIONAL_PATTERN_IN_INSTANCEOF.allowedInSource(source);
 179         sourceName = source.name;
 180         useBeforeDeclarationWarning = options.isSet("useBeforeDeclarationWarning");
 181         captureMRefReturnType = Source.Feature.CAPTURE_MREF_RETURN_TYPE.allowedInSource(source);
 182 
 183         statInfo = new ResultInfo(KindSelector.NIL, Type.noType);
 184         varAssignmentInfo = new ResultInfo(KindSelector.ASG, Type.noType);
 185         unknownExprInfo = new ResultInfo(KindSelector.VAL, Type.noType);
 186         methodAttrInfo = new MethodAttrInfo();
 187         unknownTypeInfo = new ResultInfo(KindSelector.TYP, Type.noType);
 188         unknownTypeExprInfo = new ResultInfo(KindSelector.VAL_TYP, Type.noType);
 189         recoveryInfo = new RecoveryInfo(deferredAttr.emptyDeferredAttrContext);
 190         initBlockType = new MethodType(List.nil(), syms.voidType, List.nil(), syms.methodClass);
 191         allowValueClasses = (!preview.isPreview(Feature.VALUE_CLASSES) || preview.isEnabled()) &&
 192                 Feature.VALUE_CLASSES.allowedInSource(source);
 193     }
 194 
 195     /** Switch: reifiable types in instanceof enabled?
 196      */
 197     boolean allowReifiableTypesInInstanceof;
 198 
 199     /** Are records allowed
 200      */
 201     private final boolean allowRecords;
 202 
 203     /** Are patterns in switch allowed
 204      */
 205     private final boolean allowPatternSwitch;
 206 
 207     /** Are unconditional patterns in instanceof allowed
 208      */
 209     private final boolean allowUnconditionalPatternsInstanceOf;
 210 
 211     /** Are value classes allowed
 212      */
 213     private final boolean allowValueClasses;
 214 
 215     /**
 216      * Switch: warn about use of variable before declaration?
 217      * RFE: 6425594
 218      */
 219     boolean useBeforeDeclarationWarning;
 220 
 221     /**
 222      * Switch: name of source level; used for error reporting.
 223      */
 224     String sourceName;
 225 
 226     /** Check kind and type of given tree against protokind and prototype.
 227      *  If check succeeds, store type in tree and return it.
 228      *  If check fails, store errType in tree and return it.
 229      *  No checks are performed if the prototype is a method type.
 230      *  It is not necessary in this case since we know that kind and type
 231      *  are correct.
 232      *
 233      *  @param tree     The tree whose kind and type is checked
 234      *  @param found    The computed type of the tree
 235      *  @param ownkind  The computed kind of the tree
 236      *  @param resultInfo  The expected result of the tree
 237      */
 238     Type check(final JCTree tree,
 239                final Type found,
 240                final KindSelector ownkind,
 241                final ResultInfo resultInfo) {
 242         InferenceContext inferenceContext = resultInfo.checkContext.inferenceContext();
 243         Type owntype;
 244         boolean shouldCheck = !found.hasTag(ERROR) &&
 245                 !resultInfo.pt.hasTag(METHOD) &&
 246                 !resultInfo.pt.hasTag(FORALL);
 247         if (shouldCheck && !ownkind.subset(resultInfo.pkind)) {
 248             log.error(tree.pos(),
 249                       Errors.UnexpectedType(resultInfo.pkind.kindNames(),
 250                                             ownkind.kindNames()));
 251             owntype = types.createErrorType(found);
 252         } else if (inferenceContext.free(found)) {
 253             //delay the check if there are inference variables in the found type
 254             //this means we are dealing with a partially inferred poly expression
 255             owntype = shouldCheck ? resultInfo.pt : found;
 256             if (resultInfo.checkMode.installPostInferenceHook()) {
 257                 inferenceContext.addFreeTypeListener(List.of(found),
 258                         instantiatedContext -> {
 259                             ResultInfo pendingResult =
 260                                     resultInfo.dup(inferenceContext.asInstType(resultInfo.pt));
 261                             check(tree, inferenceContext.asInstType(found), ownkind, pendingResult);
 262                         });
 263             }
 264         } else {
 265             owntype = shouldCheck ?
 266             resultInfo.check(tree, found) :
 267             found;
 268         }
 269         if (resultInfo.checkMode.updateTreeType()) {
 270             tree.type = owntype;
 271         }
 272         return owntype;
 273     }
 274 
 275     /** Is given blank final variable assignable, i.e. in a scope where it
 276      *  may be assigned to even though it is final?
 277      *  @param v      The blank final variable.
 278      *  @param env    The current environment.
 279      */
 280     boolean isAssignableAsBlankFinal(VarSymbol v, Env<AttrContext> env) {
 281         Symbol owner = env.info.scope.owner;
 282            // owner refers to the innermost variable, method or
 283            // initializer block declaration at this point.
 284         boolean isAssignable =
 285             v.owner == owner
 286             ||
 287             ((owner.name == names.init ||    // i.e. we are in a constructor
 288               owner.kind == VAR ||           // i.e. we are in a variable initializer
 289               (owner.flags() & BLOCK) != 0)  // i.e. we are in an initializer block
 290              &&
 291              v.owner == owner.owner
 292              &&
 293              ((v.flags() & STATIC) != 0) == Resolve.isStatic(env));
 294         boolean insideCompactConstructor = env.enclMethod != null && TreeInfo.isCompactConstructor(env.enclMethod);
 295         return isAssignable & !insideCompactConstructor;
 296     }
 297 
 298     /** Check that variable can be assigned to.
 299      *  @param pos    The current source code position.
 300      *  @param v      The assigned variable
 301      *  @param base   If the variable is referred to in a Select, the part
 302      *                to the left of the `.', null otherwise.
 303      *  @param env    The current environment.
 304      */
 305     void checkAssignable(DiagnosticPosition pos, VarSymbol v, JCTree base, Env<AttrContext> env) {
 306         if (v.name == names._this) {
 307             log.error(pos, Errors.CantAssignValToThis);
 308         } else if ((v.flags() & FINAL) != 0 &&
 309             ((v.flags() & HASINIT) != 0
 310              ||
 311              !((base == null ||
 312                TreeInfo.isThisQualifier(base)) &&
 313                isAssignableAsBlankFinal(v, env)))) {
 314             if (v.isResourceVariable()) { //TWR resource
 315                 log.error(pos, Errors.TryResourceMayNotBeAssigned(v));
 316             } else {
 317                 log.error(pos, Errors.CantAssignValToVar(Flags.toSource(v.flags() & (STATIC | FINAL)), v));
 318             }
 319         }
 320     }
 321 
 322     /** Does tree represent a static reference to an identifier?
 323      *  It is assumed that tree is either a SELECT or an IDENT.
 324      *  We have to weed out selects from non-type names here.
 325      *  @param tree    The candidate tree.
 326      */
 327     boolean isStaticReference(JCTree tree) {
 328         if (tree.hasTag(SELECT)) {
 329             Symbol lsym = TreeInfo.symbol(((JCFieldAccess) tree).selected);
 330             if (lsym == null || lsym.kind != TYP) {
 331                 return false;
 332             }
 333         }
 334         return true;
 335     }
 336 
 337     /** Is this symbol a type?
 338      */
 339     static boolean isType(Symbol sym) {
 340         return sym != null && sym.kind == TYP;
 341     }
 342 
 343     /** Attribute a parsed identifier.
 344      * @param tree Parsed identifier name
 345      * @param topLevel The toplevel to use
 346      */
 347     public Symbol attribIdent(JCTree tree, JCCompilationUnit topLevel) {
 348         Env<AttrContext> localEnv = enter.topLevelEnv(topLevel);
 349         localEnv.enclClass = make.ClassDef(make.Modifiers(0),
 350                                            syms.errSymbol.name,
 351                                            null, null, null, null);
 352         localEnv.enclClass.sym = syms.errSymbol;
 353         return attribIdent(tree, localEnv);
 354     }
 355 
 356     /** Attribute a parsed identifier.
 357      * @param tree Parsed identifier name
 358      * @param env The env to use
 359      */
 360     public Symbol attribIdent(JCTree tree, Env<AttrContext> env) {
 361         return tree.accept(identAttributer, env);
 362     }
 363     // where
 364         private TreeVisitor<Symbol,Env<AttrContext>> identAttributer = new IdentAttributer();
 365         private class IdentAttributer extends SimpleTreeVisitor<Symbol,Env<AttrContext>> {
 366             @Override @DefinedBy(Api.COMPILER_TREE)
 367             public Symbol visitMemberSelect(MemberSelectTree node, Env<AttrContext> env) {
 368                 Symbol site = visit(node.getExpression(), env);
 369                 if (site == null || site.kind == ERR || site.kind == ABSENT_TYP || site.kind == HIDDEN)
 370                     return site;
 371                 Name name = (Name)node.getIdentifier();
 372                 if (site.kind == PCK) {
 373                     env.toplevel.packge = (PackageSymbol)site;
 374                     return rs.findIdentInPackage(null, env, (TypeSymbol)site, name,
 375                             KindSelector.TYP_PCK);
 376                 } else {
 377                     env.enclClass.sym = (ClassSymbol)site;
 378                     return rs.findMemberType(env, site.asType(), name, (TypeSymbol)site);
 379                 }
 380             }
 381 
 382             @Override @DefinedBy(Api.COMPILER_TREE)
 383             public Symbol visitIdentifier(IdentifierTree node, Env<AttrContext> env) {
 384                 return rs.findIdent(null, env, (Name)node.getName(), KindSelector.TYP_PCK);
 385             }
 386         }
 387 
 388     public Type coerce(Type etype, Type ttype) {
 389         return cfolder.coerce(etype, ttype);
 390     }
 391 
 392     public Type attribType(JCTree node, TypeSymbol sym) {
 393         Env<AttrContext> env = typeEnvs.get(sym);
 394         Env<AttrContext> localEnv = env.dup(node, env.info.dup());
 395         return attribTree(node, localEnv, unknownTypeInfo);
 396     }
 397 
 398     public Type attribImportQualifier(JCImport tree, Env<AttrContext> env) {
 399         // Attribute qualifying package or class.
 400         JCFieldAccess s = tree.qualid;
 401         return attribTree(s.selected, env,
 402                           new ResultInfo(tree.staticImport ?
 403                                          KindSelector.TYP : KindSelector.TYP_PCK,
 404                        Type.noType));
 405     }
 406 
 407     public Env<AttrContext> attribExprToTree(JCTree expr, Env<AttrContext> env, JCTree tree) {
 408         return attribToTree(expr, env, tree, unknownExprInfo);
 409     }
 410 
 411     public Env<AttrContext> attribStatToTree(JCTree stmt, Env<AttrContext> env, JCTree tree) {
 412         return attribToTree(stmt, env, tree, statInfo);
 413     }
 414 
 415     private Env<AttrContext> attribToTree(JCTree root, Env<AttrContext> env, JCTree tree, ResultInfo resultInfo) {
 416         breakTree = tree;
 417         JavaFileObject prev = log.useSource(env.toplevel.sourcefile);
 418         try {
 419             deferredAttr.attribSpeculative(root, env, resultInfo,
 420                     null, DeferredAttr.AttributionMode.ATTRIB_TO_TREE,
 421                     argumentAttr.withLocalCacheContext());
 422             attrRecover.doRecovery();
 423         } catch (BreakAttr b) {
 424             return b.env;
 425         } catch (AssertionError ae) {
 426             if (ae.getCause() instanceof BreakAttr breakAttr) {
 427                 return breakAttr.env;
 428             } else {
 429                 throw ae;
 430             }
 431         } finally {
 432             breakTree = null;
 433             log.useSource(prev);
 434         }
 435         return env;
 436     }
 437 
 438     private JCTree breakTree = null;
 439 
 440     private static class BreakAttr extends RuntimeException {
 441         static final long serialVersionUID = -6924771130405446405L;
 442         private transient Env<AttrContext> env;
 443         private BreakAttr(Env<AttrContext> env) {
 444             this.env = env;
 445         }
 446     }
 447 
 448     /**
 449      * Mode controlling behavior of Attr.Check
 450      */
 451     enum CheckMode {
 452 
 453         NORMAL,
 454 
 455         /**
 456          * Mode signalling 'fake check' - skip tree update. A side-effect of this mode is
 457          * that the captured var cache in {@code InferenceContext} will be used in read-only
 458          * mode when performing inference checks.
 459          */
 460         NO_TREE_UPDATE {
 461             @Override
 462             public boolean updateTreeType() {
 463                 return false;
 464             }
 465         },
 466         /**
 467          * Mode signalling that caller will manage free types in tree decorations.
 468          */
 469         NO_INFERENCE_HOOK {
 470             @Override
 471             public boolean installPostInferenceHook() {
 472                 return false;
 473             }
 474         };
 475 
 476         public boolean updateTreeType() {
 477             return true;
 478         }
 479         public boolean installPostInferenceHook() {
 480             return true;
 481         }
 482     }
 483 
 484 
 485     class ResultInfo {
 486         final KindSelector pkind;
 487         final Type pt;
 488         final CheckContext checkContext;
 489         final CheckMode checkMode;
 490 
 491         ResultInfo(KindSelector pkind, Type pt) {
 492             this(pkind, pt, chk.basicHandler, CheckMode.NORMAL);
 493         }
 494 
 495         ResultInfo(KindSelector pkind, Type pt, CheckMode checkMode) {
 496             this(pkind, pt, chk.basicHandler, checkMode);
 497         }
 498 
 499         protected ResultInfo(KindSelector pkind,
 500                              Type pt, CheckContext checkContext) {
 501             this(pkind, pt, checkContext, CheckMode.NORMAL);
 502         }
 503 
 504         protected ResultInfo(KindSelector pkind,
 505                              Type pt, CheckContext checkContext, CheckMode checkMode) {
 506             this.pkind = pkind;
 507             this.pt = pt;
 508             this.checkContext = checkContext;
 509             this.checkMode = checkMode;
 510         }
 511 
 512         /**
 513          * Should {@link Attr#attribTree} use the {@code ArgumentAttr} visitor instead of this one?
 514          * @param tree The tree to be type-checked.
 515          * @return true if {@code ArgumentAttr} should be used.
 516          */
 517         protected boolean needsArgumentAttr(JCTree tree) { return false; }
 518 
 519         protected Type check(final DiagnosticPosition pos, final Type found) {
 520             return chk.checkType(pos, found, pt, checkContext);
 521         }
 522 
 523         protected ResultInfo dup(Type newPt) {
 524             return new ResultInfo(pkind, newPt, checkContext, checkMode);
 525         }
 526 
 527         protected ResultInfo dup(CheckContext newContext) {
 528             return new ResultInfo(pkind, pt, newContext, checkMode);
 529         }
 530 
 531         protected ResultInfo dup(Type newPt, CheckContext newContext) {
 532             return new ResultInfo(pkind, newPt, newContext, checkMode);
 533         }
 534 
 535         protected ResultInfo dup(Type newPt, CheckContext newContext, CheckMode newMode) {
 536             return new ResultInfo(pkind, newPt, newContext, newMode);
 537         }
 538 
 539         protected ResultInfo dup(CheckMode newMode) {
 540             return new ResultInfo(pkind, pt, checkContext, newMode);
 541         }
 542 
 543         @Override
 544         public String toString() {
 545             if (pt != null) {
 546                 return pt.toString();
 547             } else {
 548                 return "";
 549             }
 550         }
 551     }
 552 
 553     class MethodAttrInfo extends ResultInfo {
 554         public MethodAttrInfo() {
 555             this(chk.basicHandler);
 556         }
 557 
 558         public MethodAttrInfo(CheckContext checkContext) {
 559             super(KindSelector.VAL, Infer.anyPoly, checkContext);
 560         }
 561 
 562         @Override
 563         protected boolean needsArgumentAttr(JCTree tree) {
 564             return true;
 565         }
 566 
 567         protected ResultInfo dup(Type newPt) {
 568             throw new IllegalStateException();
 569         }
 570 
 571         protected ResultInfo dup(CheckContext newContext) {
 572             return new MethodAttrInfo(newContext);
 573         }
 574 
 575         protected ResultInfo dup(Type newPt, CheckContext newContext) {
 576             throw new IllegalStateException();
 577         }
 578 
 579         protected ResultInfo dup(Type newPt, CheckContext newContext, CheckMode newMode) {
 580             throw new IllegalStateException();
 581         }
 582 
 583         protected ResultInfo dup(CheckMode newMode) {
 584             throw new IllegalStateException();
 585         }
 586     }
 587 
 588     class RecoveryInfo extends ResultInfo {
 589 
 590         public RecoveryInfo(final DeferredAttr.DeferredAttrContext deferredAttrContext) {
 591             this(deferredAttrContext, Type.recoveryType);
 592         }
 593 
 594         public RecoveryInfo(final DeferredAttr.DeferredAttrContext deferredAttrContext, Type pt) {
 595             super(KindSelector.VAL, pt, new Check.NestedCheckContext(chk.basicHandler) {
 596                 @Override
 597                 public DeferredAttr.DeferredAttrContext deferredAttrContext() {
 598                     return deferredAttrContext;
 599                 }
 600                 @Override
 601                 public boolean compatible(Type found, Type req, Warner warn) {
 602                     return true;
 603                 }
 604                 @Override
 605                 public void report(DiagnosticPosition pos, JCDiagnostic details) {
 606                     boolean needsReport = pt == Type.recoveryType ||
 607                             (details.getDiagnosticPosition() != null &&
 608                             details.getDiagnosticPosition().getTree().hasTag(LAMBDA));
 609                     if (needsReport) {
 610                         chk.basicHandler.report(pos, details);
 611                     }
 612                 }
 613             });
 614         }
 615     }
 616 
 617     final ResultInfo statInfo;
 618     final ResultInfo varAssignmentInfo;
 619     final ResultInfo methodAttrInfo;
 620     final ResultInfo unknownExprInfo;
 621     final ResultInfo unknownTypeInfo;
 622     final ResultInfo unknownTypeExprInfo;
 623     final ResultInfo recoveryInfo;
 624     final MethodType initBlockType;
 625 
 626     Type pt() {
 627         return resultInfo.pt;
 628     }
 629 
 630     KindSelector pkind() {
 631         return resultInfo.pkind;
 632     }
 633 
 634 /* ************************************************************************
 635  * Visitor methods
 636  *************************************************************************/
 637 
 638     /** Visitor argument: the current environment.
 639      */
 640     Env<AttrContext> env;
 641 
 642     /** Visitor argument: the currently expected attribution result.
 643      */
 644     ResultInfo resultInfo;
 645 
 646     /** Visitor result: the computed type.
 647      */
 648     Type result;
 649 
 650     MatchBindings matchBindings = MatchBindingsComputer.EMPTY;
 651 
 652     /** Visitor method: attribute a tree, catching any completion failure
 653      *  exceptions. Return the tree's type.
 654      *
 655      *  @param tree    The tree to be visited.
 656      *  @param env     The environment visitor argument.
 657      *  @param resultInfo   The result info visitor argument.
 658      */
 659     Type attribTree(JCTree tree, Env<AttrContext> env, ResultInfo resultInfo) {
 660         Env<AttrContext> prevEnv = this.env;
 661         ResultInfo prevResult = this.resultInfo;
 662         try {
 663             this.env = env;
 664             this.resultInfo = resultInfo;
 665             if (resultInfo.needsArgumentAttr(tree)) {
 666                 result = argumentAttr.attribArg(tree, env);
 667             } else {
 668                 tree.accept(this);
 669             }
 670             matchBindings = matchBindingsComputer.finishBindings(tree,
 671                                                                  matchBindings);
 672             if (tree == breakTree &&
 673                     resultInfo.checkContext.deferredAttrContext().mode == AttrMode.CHECK) {
 674                 breakTreeFound(copyEnv(env));
 675             }
 676             return result;
 677         } catch (CompletionFailure ex) {
 678             tree.type = syms.errType;
 679             return chk.completionError(tree.pos(), ex);
 680         } finally {
 681             this.env = prevEnv;
 682             this.resultInfo = prevResult;
 683         }
 684     }
 685 
 686     protected void breakTreeFound(Env<AttrContext> env) {
 687         throw new BreakAttr(env);
 688     }
 689 
 690     Env<AttrContext> copyEnv(Env<AttrContext> env) {
 691         Env<AttrContext> newEnv =
 692                 env.dup(env.tree, env.info.dup(copyScope(env.info.scope)));
 693         if (newEnv.outer != null) {
 694             newEnv.outer = copyEnv(newEnv.outer);
 695         }
 696         return newEnv;
 697     }
 698 
 699     WriteableScope copyScope(WriteableScope sc) {
 700         WriteableScope newScope = WriteableScope.create(sc.owner);
 701         List<Symbol> elemsList = List.nil();
 702         for (Symbol sym : sc.getSymbols()) {
 703             elemsList = elemsList.prepend(sym);
 704         }
 705         for (Symbol s : elemsList) {
 706             newScope.enter(s);
 707         }
 708         return newScope;
 709     }
 710 
 711     /** Derived visitor method: attribute an expression tree.
 712      */
 713     public Type attribExpr(JCTree tree, Env<AttrContext> env, Type pt) {
 714         return attribTree(tree, env, new ResultInfo(KindSelector.VAL, !pt.hasTag(ERROR) ? pt : Type.noType));
 715     }
 716 
 717     /** Derived visitor method: attribute an expression tree with
 718      *  no constraints on the computed type.
 719      */
 720     public Type attribExpr(JCTree tree, Env<AttrContext> env) {
 721         return attribTree(tree, env, unknownExprInfo);
 722     }
 723 
 724     /** Derived visitor method: attribute a type tree.
 725      */
 726     public Type attribType(JCTree tree, Env<AttrContext> env) {
 727         Type result = attribType(tree, env, Type.noType);
 728         return result;
 729     }
 730 
 731     /** Derived visitor method: attribute a type tree.
 732      */
 733     Type attribType(JCTree tree, Env<AttrContext> env, Type pt) {
 734         Type result = attribTree(tree, env, new ResultInfo(KindSelector.TYP, pt));
 735         return result;
 736     }
 737 
 738     /** Derived visitor method: attribute a statement or definition tree.
 739      */
 740     public Type attribStat(JCTree tree, Env<AttrContext> env) {
 741         Env<AttrContext> analyzeEnv = analyzer.copyEnvIfNeeded(tree, env);
 742         Type result = attribTree(tree, env, statInfo);
 743         analyzer.analyzeIfNeeded(tree, analyzeEnv);
 744         attrRecover.doRecovery();
 745         return result;
 746     }
 747 
 748     /** Attribute a list of expressions, returning a list of types.
 749      */
 750     List<Type> attribExprs(List<JCExpression> trees, Env<AttrContext> env, Type pt) {
 751         ListBuffer<Type> ts = new ListBuffer<>();
 752         for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail)
 753             ts.append(attribExpr(l.head, env, pt));
 754         return ts.toList();
 755     }
 756 
 757     /** Attribute a list of statements, returning nothing.
 758      */
 759     <T extends JCTree> void attribStats(List<T> trees, Env<AttrContext> env) {
 760         for (List<T> l = trees; l.nonEmpty(); l = l.tail)
 761             attribStat(l.head, env);
 762     }
 763 
 764     /** Attribute the arguments in a method call, returning the method kind.
 765      */
 766     KindSelector attribArgs(KindSelector initialKind, List<JCExpression> trees, Env<AttrContext> env, ListBuffer<Type> argtypes) {
 767         KindSelector kind = initialKind;
 768         for (JCExpression arg : trees) {
 769             Type argtype = chk.checkNonVoid(arg, attribTree(arg, env, methodAttrInfo));
 770             if (argtype.hasTag(DEFERRED)) {
 771                 kind = KindSelector.of(KindSelector.POLY, kind);
 772             }
 773             argtypes.append(argtype);
 774         }
 775         return kind;
 776     }
 777 
 778     /** Attribute a type argument list, returning a list of types.
 779      *  Caller is responsible for calling checkRefTypes.
 780      */
 781     List<Type> attribAnyTypes(List<JCExpression> trees, Env<AttrContext> env) {
 782         ListBuffer<Type> argtypes = new ListBuffer<>();
 783         for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail)
 784             argtypes.append(attribType(l.head, env));
 785         return argtypes.toList();
 786     }
 787 
 788     /** Attribute a type argument list, returning a list of types.
 789      *  Check that all the types are references.
 790      */
 791     List<Type> attribTypes(List<JCExpression> trees, Env<AttrContext> env) {
 792         List<Type> types = attribAnyTypes(trees, env);
 793         return chk.checkRefTypes(trees, types);
 794     }
 795 
 796     /**
 797      * Attribute type variables (of generic classes or methods).
 798      * Compound types are attributed later in attribBounds.
 799      * @param typarams the type variables to enter
 800      * @param env      the current environment
 801      */
 802     void attribTypeVariables(List<JCTypeParameter> typarams, Env<AttrContext> env, boolean checkCyclic) {
 803         for (JCTypeParameter tvar : typarams) {
 804             TypeVar a = (TypeVar)tvar.type;
 805             a.tsym.flags_field |= UNATTRIBUTED;
 806             a.setUpperBound(Type.noType);
 807             if (!tvar.bounds.isEmpty()) {
 808                 List<Type> bounds = List.of(attribType(tvar.bounds.head, env));
 809                 for (JCExpression bound : tvar.bounds.tail)
 810                     bounds = bounds.prepend(attribType(bound, env));
 811                 types.setBounds(a, bounds.reverse());
 812             } else {
 813                 // if no bounds are given, assume a single bound of
 814                 // java.lang.Object.
 815                 types.setBounds(a, List.of(syms.objectType));
 816             }
 817             a.tsym.flags_field &= ~UNATTRIBUTED;
 818         }
 819         if (checkCyclic) {
 820             for (JCTypeParameter tvar : typarams) {
 821                 chk.checkNonCyclic(tvar.pos(), (TypeVar)tvar.type);
 822             }
 823         }
 824     }
 825 
 826     /**
 827      * Attribute the type references in a list of annotations.
 828      */
 829     void attribAnnotationTypes(List<JCAnnotation> annotations,
 830                                Env<AttrContext> env) {
 831         for (List<JCAnnotation> al = annotations; al.nonEmpty(); al = al.tail) {
 832             JCAnnotation a = al.head;
 833             attribType(a.annotationType, env);
 834         }
 835     }
 836 
 837     /**
 838      * Attribute a "lazy constant value".
 839      *  @param env         The env for the const value
 840      *  @param variable    The initializer for the const value
 841      *  @param type        The expected type, or null
 842      *  @see VarSymbol#setLazyConstValue
 843      */
 844     public Object attribLazyConstantValue(Env<AttrContext> env,
 845                                       Env<AttrContext> enclosingEnv,
 846                                       JCVariableDecl variable,
 847                                       Type type) {
 848         final JavaFileObject prevSource = log.useSource(env.toplevel.sourcefile);
 849         try {
 850             doQueueScanTreeAndTypeAnnotateForVarInit(variable, enclosingEnv);
 851             Type itype = attribExpr(variable.init, env, type);
 852             if (variable.isImplicitlyTyped()) {
 853                 //fixup local variable type
 854                 type = variable.type = variable.sym.type = chk.checkLocalVarType(variable, itype, variable.name);
 855             }
 856             if (itype.constValue() != null) {
 857                 return coerce(itype, type).constValue();
 858             } else {
 859                 return null;
 860             }
 861         } finally {
 862             log.useSource(prevSource);
 863         }
 864     }
 865 
 866     /** Attribute type reference in an `extends', `implements', or 'permits' clause.
 867      *  Supertypes of anonymous inner classes are usually already attributed.
 868      *
 869      *  @param tree              The tree making up the type reference.
 870      *  @param env               The environment current at the reference.
 871      *  @param classExpected     true if only a class is expected here.
 872      *  @param interfaceExpected true if only an interface is expected here.
 873      */
 874     Type attribBase(JCTree tree,
 875                     Env<AttrContext> env,
 876                     boolean classExpected,
 877                     boolean interfaceExpected,
 878                     boolean checkExtensible) {
 879         Type t = tree.type != null ?
 880             tree.type :
 881             attribType(tree, env);
 882         try {
 883             return checkBase(t, tree, env, classExpected, interfaceExpected, checkExtensible);
 884         } catch (CompletionFailure ex) {
 885             chk.completionError(tree.pos(), ex);
 886             return t;
 887         }
 888     }
 889     Type checkBase(Type t,
 890                    JCTree tree,
 891                    Env<AttrContext> env,
 892                    boolean classExpected,
 893                    boolean interfaceExpected,
 894                    boolean checkExtensible) {
 895         final DiagnosticPosition pos = tree.hasTag(TYPEAPPLY) ?
 896                 (((JCTypeApply) tree).clazz).pos() : tree.pos();
 897         if (t.tsym.isAnonymous()) {
 898             log.error(pos, Errors.CantInheritFromAnon);
 899             return types.createErrorType(t);
 900         }
 901         if (t.isErroneous())
 902             return t;
 903         if (t.hasTag(TYPEVAR) && !classExpected && !interfaceExpected) {
 904             // check that type variable is already visible
 905             if (t.getUpperBound() == null) {
 906                 log.error(pos, Errors.IllegalForwardRef);
 907                 return types.createErrorType(t);
 908             }
 909         } else {
 910             t = chk.checkClassType(pos, t, checkExtensible);
 911         }
 912         if (interfaceExpected && (t.tsym.flags() & INTERFACE) == 0) {
 913             log.error(pos, Errors.IntfExpectedHere);
 914             // return errType is necessary since otherwise there might
 915             // be undetected cycles which cause attribution to loop
 916             return types.createErrorType(t);
 917         } else if (checkExtensible &&
 918                    classExpected &&
 919                    (t.tsym.flags() & INTERFACE) != 0) {
 920             log.error(pos, Errors.NoIntfExpectedHere);
 921             return types.createErrorType(t);
 922         }
 923         if (checkExtensible &&
 924             ((t.tsym.flags() & FINAL) != 0)) {
 925             log.error(pos,
 926                       Errors.CantInheritFromFinal(t.tsym));
 927         }
 928         chk.checkNonCyclic(pos, t);
 929         return t;
 930     }
 931 
 932     Type attribIdentAsEnumType(Env<AttrContext> env, JCIdent id) {
 933         Assert.check((env.enclClass.sym.flags() & ENUM) != 0);
 934         id.type = env.info.scope.owner.enclClass().type;
 935         id.sym = env.info.scope.owner.enclClass();
 936         return id.type;
 937     }
 938 
 939     public void visitClassDef(JCClassDecl tree) {
 940         Optional<ArgumentAttr.LocalCacheContext> localCacheContext =
 941                 Optional.ofNullable(env.info.attributionMode.isSpeculative ?
 942                         argumentAttr.withLocalCacheContext() : null);
 943         boolean ctorProloguePrev = env.info.ctorPrologue;
 944         try {
 945             // Local and anonymous classes have not been entered yet, so we need to
 946             // do it now.
 947             if (env.info.scope.owner.kind.matches(KindSelector.VAL_MTH)) {
 948                 enter.classEnter(tree, env);
 949             } else {
 950                 // If this class declaration is part of a class level annotation,
 951                 // as in @MyAnno(new Object() {}) class MyClass {}, enter it in
 952                 // order to simplify later steps and allow for sensible error
 953                 // messages.
 954                 if (env.tree.hasTag(NEWCLASS) && TreeInfo.isInAnnotation(env, tree))
 955                     enter.classEnter(tree, env);
 956             }
 957 
 958             ClassSymbol c = tree.sym;
 959             if (c == null) {
 960                 // exit in case something drastic went wrong during enter.
 961                 result = null;
 962             } else {
 963                 // make sure class has been completed:
 964                 c.complete();
 965 
 966                 // If a class declaration appears in a constructor prologue,
 967                 // that means it's either a local class or an anonymous class.
 968                 // Either way, there is no immediately enclosing instance.
 969                 if (ctorProloguePrev) {
 970                     c.flags_field |= NOOUTERTHIS;
 971                 }
 972                 attribClass(tree.pos(), c);
 973                 result = tree.type = c.type;
 974             }
 975         } finally {
 976             localCacheContext.ifPresent(LocalCacheContext::leave);
 977             env.info.ctorPrologue = ctorProloguePrev;
 978         }
 979     }
 980 
 981     public void visitMethodDef(JCMethodDecl tree) {
 982         MethodSymbol m = tree.sym;
 983         boolean isDefaultMethod = (m.flags() & DEFAULT) != 0;
 984 
 985         Lint lint = env.info.lint.augment(m);
 986         Lint prevLint = chk.setLint(lint);
 987         boolean ctorProloguePrev = env.info.ctorPrologue;
 988         Assert.check(!env.info.ctorPrologue);
 989         MethodSymbol prevMethod = chk.setMethod(m);
 990         try {
 991             chk.checkDeprecatedAnnotation(tree.pos(), m);
 992 
 993 
 994             // Create a new environment with local scope
 995             // for attributing the method.
 996             Env<AttrContext> localEnv = memberEnter.methodEnv(tree, env);
 997             localEnv.info.lint = lint;
 998 
 999             attribStats(tree.typarams, localEnv);
1000 
1001             // If we override any other methods, check that we do so properly.
1002             // JLS ???
1003             if (m.isStatic()) {
1004                 chk.checkHideClashes(tree.pos(), env.enclClass.type, m);
1005             } else {
1006                 chk.checkOverrideClashes(tree.pos(), env.enclClass.type, m);
1007             }
1008             chk.checkOverride(env, tree, m);
1009 
1010             if (isDefaultMethod && types.overridesObjectMethod(m.enclClass(), m)) {
1011                 log.error(tree, Errors.DefaultOverridesObjectMember(m.name, Kinds.kindName(m.location()), m.location()));
1012             }
1013 
1014             // Enter all type parameters into the local method scope.
1015             for (List<JCTypeParameter> l = tree.typarams; l.nonEmpty(); l = l.tail)
1016                 localEnv.info.scope.enterIfAbsent(l.head.type.tsym);
1017 
1018             ClassSymbol owner = env.enclClass.sym;
1019             if ((owner.flags() & ANNOTATION) != 0 &&
1020                     (tree.params.nonEmpty() ||
1021                     tree.recvparam != null))
1022                 log.error(tree.params.nonEmpty() ?
1023                         tree.params.head.pos() :
1024                         tree.recvparam.pos(),
1025                         Errors.IntfAnnotationMembersCantHaveParams);
1026 
1027             // Attribute all value parameters.
1028             for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
1029                 attribStat(l.head, localEnv);
1030             }
1031 
1032             chk.checkVarargsMethodDecl(localEnv, tree);
1033 
1034             // Check that type parameters are well-formed.
1035             chk.validate(tree.typarams, localEnv);
1036 
1037             // Check that result type is well-formed.
1038             if (tree.restype != null && !tree.restype.type.hasTag(VOID)) {
1039                 chk.validate(tree.restype, localEnv);
1040             }
1041             chk.checkRequiresIdentity(tree, env.info.lint);
1042 
1043             // Check that receiver type is well-formed.
1044             if (tree.recvparam != null) {
1045                 // Use a new environment to check the receiver parameter.
1046                 // Otherwise I get "might not have been initialized" errors.
1047                 // Is there a better way?
1048                 Env<AttrContext> newEnv = memberEnter.methodEnv(tree, env);
1049                 attribType(tree.recvparam, newEnv);
1050                 chk.validate(tree.recvparam, newEnv);
1051             }
1052 
1053             // Is this method a constructor?
1054             boolean isConstructor = TreeInfo.isConstructor(tree);
1055 
1056             if (env.enclClass.sym.isRecord() && tree.sym.owner.kind == TYP) {
1057                 // lets find if this method is an accessor
1058                 Optional<? extends RecordComponent> recordComponent = env.enclClass.sym.getRecordComponents().stream()
1059                         .filter(rc -> rc.accessor == tree.sym && (rc.accessor.flags_field & GENERATED_MEMBER) == 0).findFirst();
1060                 if (recordComponent.isPresent()) {
1061                     // the method is a user defined accessor lets check that everything is fine
1062                     if (!tree.sym.isPublic()) {
1063                         log.error(tree, Errors.InvalidAccessorMethodInRecord(env.enclClass.sym, Fragments.MethodMustBePublic));
1064                     }
1065                     if (!types.isSameType(tree.sym.type.getReturnType(), recordComponent.get().type)) {
1066                         log.error(tree, Errors.InvalidAccessorMethodInRecord(env.enclClass.sym,
1067                                 Fragments.AccessorReturnTypeDoesntMatch(tree.sym, recordComponent.get())));
1068                     }
1069                     if (tree.sym.type.asMethodType().thrown != null && !tree.sym.type.asMethodType().thrown.isEmpty()) {
1070                         log.error(tree,
1071                                 Errors.InvalidAccessorMethodInRecord(env.enclClass.sym, Fragments.AccessorMethodCantThrowException));
1072                     }
1073                     if (!tree.typarams.isEmpty()) {
1074                         log.error(tree,
1075                                 Errors.InvalidAccessorMethodInRecord(env.enclClass.sym, Fragments.AccessorMethodMustNotBeGeneric));
1076                     }
1077                     if (tree.sym.isStatic()) {
1078                         log.error(tree,
1079                                 Errors.InvalidAccessorMethodInRecord(env.enclClass.sym, Fragments.AccessorMethodMustNotBeStatic));
1080                     }
1081                 }
1082 
1083                 if (isConstructor) {
1084                     // if this a constructor other than the canonical one
1085                     if ((tree.sym.flags_field & RECORD) == 0) {
1086                         if (!TreeInfo.hasConstructorCall(tree, names._this)) {
1087                             log.error(tree, Errors.NonCanonicalConstructorInvokeAnotherConstructor(env.enclClass.sym));
1088                         }
1089                     } else {
1090                         // but if it is the canonical:
1091 
1092                         /* if user generated, then it shouldn't:
1093                          *     - have an accessibility stricter than that of the record type
1094                          *     - explicitly invoke any other constructor
1095                          */
1096                         if ((tree.sym.flags_field & GENERATEDCONSTR) == 0) {
1097                             if (Check.protection(m.flags()) > Check.protection(env.enclClass.sym.flags())) {
1098                                 log.error(tree,
1099                                         (env.enclClass.sym.flags() & AccessFlags) == 0 ?
1100                                             Errors.InvalidCanonicalConstructorInRecord(
1101                                                 Fragments.Canonical,
1102                                                 env.enclClass.sym.name,
1103                                                 Fragments.CanonicalMustNotHaveStrongerAccess("package")
1104                                             ) :
1105                                             Errors.InvalidCanonicalConstructorInRecord(
1106                                                     Fragments.Canonical,
1107                                                     env.enclClass.sym.name,
1108                                                     Fragments.CanonicalMustNotHaveStrongerAccess(asFlagSet(env.enclClass.sym.flags() & AccessFlags))
1109                                             )
1110                                 );
1111                             }
1112 
1113                             if ((!allowValueClasses || TreeInfo.isCompactConstructor(tree)) &&
1114                                     TreeInfo.hasAnyConstructorCall(tree)) {
1115                                 log.error(tree, Errors.InvalidCanonicalConstructorInRecord(
1116                                         Fragments.Canonical, env.enclClass.sym.name,
1117                                         Fragments.CanonicalMustNotContainExplicitConstructorInvocation));
1118                             }
1119                         }
1120 
1121                         // also we want to check that no type variables have been defined
1122                         if (!tree.typarams.isEmpty()) {
1123                             log.error(tree, Errors.InvalidCanonicalConstructorInRecord(
1124                                     Fragments.Canonical, env.enclClass.sym.name, Fragments.CanonicalMustNotDeclareTypeVariables));
1125                         }
1126 
1127                         /* and now we need to check that the constructor's arguments are exactly the same as those of the
1128                          * record components
1129                          */
1130                         List<? extends RecordComponent> recordComponents = env.enclClass.sym.getRecordComponents();
1131                         List<Type> recordFieldTypes = TreeInfo.recordFields(env.enclClass).map(vd -> vd.sym.type);
1132                         for (JCVariableDecl param: tree.params) {
1133                             boolean paramIsVarArgs = (param.sym.flags_field & VARARGS) != 0;
1134                             if (!types.isSameType(param.type, recordFieldTypes.head) ||
1135                                     (recordComponents.head.isVarargs() != paramIsVarArgs)) {
1136                                 log.error(param, Errors.InvalidCanonicalConstructorInRecord(
1137                                         Fragments.Canonical, env.enclClass.sym.name,
1138                                         Fragments.TypeMustBeIdenticalToCorrespondingRecordComponentType));
1139                             }
1140                             recordComponents = recordComponents.tail;
1141                             recordFieldTypes = recordFieldTypes.tail;
1142                         }
1143                     }
1144                 }
1145             }
1146 
1147             // annotation method checks
1148             if ((owner.flags() & ANNOTATION) != 0) {
1149                 // annotation method cannot have throws clause
1150                 if (tree.thrown.nonEmpty()) {
1151                     log.error(tree.thrown.head.pos(),
1152                               Errors.ThrowsNotAllowedInIntfAnnotation);
1153                 }
1154                 // annotation method cannot declare type-parameters
1155                 if (tree.typarams.nonEmpty()) {
1156                     log.error(tree.typarams.head.pos(),
1157                               Errors.IntfAnnotationMembersCantHaveTypeParams);
1158                 }
1159                 // validate annotation method's return type (could be an annotation type)
1160                 chk.validateAnnotationType(tree.restype);
1161                 // ensure that annotation method does not clash with members of Object/Annotation
1162                 chk.validateAnnotationMethod(tree.pos(), m);
1163             }
1164 
1165             for (List<JCExpression> l = tree.thrown; l.nonEmpty(); l = l.tail)
1166                 chk.checkType(l.head.pos(), l.head.type, syms.throwableType);
1167 
1168             if (tree.body == null) {
1169                 // Empty bodies are only allowed for
1170                 // abstract, native, or interface methods, or for methods
1171                 // in a retrofit signature class.
1172                 if (tree.defaultValue != null) {
1173                     if ((owner.flags() & ANNOTATION) == 0)
1174                         log.error(tree.pos(),
1175                                   Errors.DefaultAllowedInIntfAnnotationMember);
1176                 }
1177                 if (isDefaultMethod || (tree.sym.flags() & (ABSTRACT | NATIVE)) == 0)
1178                     log.error(tree.pos(), Errors.MissingMethBodyOrDeclAbstract(tree.sym, owner));
1179             } else {
1180                 if ((tree.sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
1181                     if ((owner.flags() & INTERFACE) != 0) {
1182                         log.error(tree.body.pos(), Errors.IntfMethCantHaveBody);
1183                     } else {
1184                         log.error(tree.pos(), Errors.AbstractMethCantHaveBody);
1185                     }
1186                 } else if ((tree.mods.flags & NATIVE) != 0) {
1187                     log.error(tree.pos(), Errors.NativeMethCantHaveBody);
1188                 }
1189                 // Add an implicit super() call unless an explicit call to
1190                 // super(...) or this(...) is given
1191                 // or we are compiling class java.lang.Object.
1192                 boolean addedSuperInIdentityClass = false;
1193                 if (isConstructor && owner.type != syms.objectType) {
1194                     if (!TreeInfo.hasAnyConstructorCall(tree)) {
1195                         JCStatement supCall = make.at(tree.body.pos).Exec(make.Apply(List.nil(),
1196                                 make.Ident(names._super), make.Idents(List.nil())));
1197                         if (allowValueClasses && (owner.isValueClass() || ((owner.flags_field & RECORD) != 0))) {
1198                             tree.body.stats = tree.body.stats.append(supCall);
1199                         } else {
1200                             tree.body.stats = tree.body.stats.prepend(supCall);
1201                             addedSuperInIdentityClass = true;
1202                         }
1203                     } else if ((env.enclClass.sym.flags() & ENUM) != 0 &&
1204                             (tree.mods.flags & GENERATEDCONSTR) == 0 &&
1205                             TreeInfo.hasConstructorCall(tree, names._super)) {
1206                         // enum constructors are not allowed to call super
1207                         // directly, so make sure there aren't any super calls
1208                         // in enum constructors, except in the compiler
1209                         // generated one.
1210                         log.error(tree.body.stats.head.pos(),
1211                                   Errors.CallToSuperNotAllowedInEnumCtor(env.enclClass.sym));
1212                     }
1213                     if (env.enclClass.sym.isRecord() && (tree.sym.flags_field & RECORD) != 0) { // we are seeing the canonical constructor
1214                         List<Name> recordComponentNames = TreeInfo.recordFields(env.enclClass).map(vd -> vd.sym.name);
1215                         List<Name> initParamNames = tree.sym.params.map(p -> p.name);
1216                         if (!initParamNames.equals(recordComponentNames)) {
1217                             log.error(tree, Errors.InvalidCanonicalConstructorInRecord(
1218                                     Fragments.Canonical, env.enclClass.sym.name, Fragments.CanonicalWithNameMismatch));
1219                         }
1220                         if (tree.sym.type.asMethodType().thrown != null && !tree.sym.type.asMethodType().thrown.isEmpty()) {
1221                             log.error(tree,
1222                                     Errors.InvalidCanonicalConstructorInRecord(
1223                                             TreeInfo.isCompactConstructor(tree) ? Fragments.Compact : Fragments.Canonical,
1224                                             env.enclClass.sym.name,
1225                                             Fragments.ThrowsClauseNotAllowedForCanonicalConstructor(
1226                                                     TreeInfo.isCompactConstructor(tree) ? Fragments.Compact : Fragments.Canonical)));
1227                         }
1228                     }
1229                 }
1230 
1231                 // Attribute all type annotations in the body
1232                 annotate.queueScanTreeAndTypeAnnotate(tree.body, localEnv, m);
1233                 annotate.flush();
1234 
1235                 // Start of constructor prologue (if not in java.lang.Object constructor)
1236                 localEnv.info.ctorPrologue = isConstructor && owner.type != syms.objectType;
1237 
1238                 // Attribute method body.
1239                 attribStat(tree.body, localEnv);
1240                 if (localEnv.info.ctorPrologue) {
1241                     boolean thisInvocation = false;
1242                     ListBuffer<JCTree> prologueCode = new ListBuffer<>();
1243                     for (JCTree stat : tree.body.stats) {
1244                         prologueCode.add(stat);
1245                         /* gather all the stats in the body until a `super` or `this` constructor invocation is found,
1246                          * including the constructor invocation, that way we don't need to worry in the visitor below if
1247                          * if we are dealing or not with prologue code
1248                          */
1249                         if (stat instanceof JCExpressionStatement expStmt &&
1250                                 expStmt.expr instanceof JCMethodInvocation mi &&
1251                                 TreeInfo.isConstructorCall(mi)) {
1252                             thisInvocation = TreeInfo.name(mi.meth) == names._this;
1253                             if (!addedSuperInIdentityClass || !allowValueClasses) {
1254                                 break;
1255                             }
1256                         }
1257                     }
1258                     if (!prologueCode.isEmpty()) {
1259                         CtorPrologueVisitor ctorPrologueVisitor = new CtorPrologueVisitor(localEnv,
1260                                 addedSuperInIdentityClass && allowValueClasses ?
1261                                         PrologueVisitorMode.WARNINGS_ONLY :
1262                                         thisInvocation ?
1263                                                 PrologueVisitorMode.THIS_CONSTRUCTOR :
1264                                                 PrologueVisitorMode.SUPER_CONSTRUCTOR,
1265                                 false);
1266                         ctorPrologueVisitor.scan(prologueCode.toList());
1267                     }
1268                 }
1269             }
1270 
1271             localEnv.info.scope.leave();
1272             result = tree.type = m.type;
1273         } finally {
1274             chk.setLint(prevLint);
1275             chk.setMethod(prevMethod);
1276             env.info.ctorPrologue = ctorProloguePrev;
1277         }
1278     }
1279 
1280     enum PrologueVisitorMode {
1281         WARNINGS_ONLY,
1282         SUPER_CONSTRUCTOR,
1283         THIS_CONSTRUCTOR
1284     }
1285 
1286     class CtorPrologueVisitor extends TreeScanner {
1287         Env<AttrContext> localEnv;
1288         PrologueVisitorMode mode;
1289         boolean isInitializer;
1290 
1291         CtorPrologueVisitor(Env<AttrContext> localEnv, PrologueVisitorMode mode, boolean isInitializer) {
1292             this.localEnv = localEnv;
1293             currentClassSym = localEnv.enclClass.sym;
1294             this.mode = mode;
1295             this.isInitializer = isInitializer;
1296         }
1297 
1298         boolean insideLambdaOrClassDef = false;
1299 
1300         @Override
1301         public void visitLambda(JCLambda lambda) {
1302             boolean previousInsideLambdaOrClassDef = insideLambdaOrClassDef;
1303             try {
1304                 insideLambdaOrClassDef = true;
1305                 super.visitLambda(lambda);
1306             } finally {
1307                 insideLambdaOrClassDef = previousInsideLambdaOrClassDef;
1308             }
1309         }
1310 
1311         ClassSymbol currentClassSym;
1312 
1313         @Override
1314         public void visitClassDef(JCClassDecl classDecl) {
1315             boolean previousInsideLambdaOrClassDef = insideLambdaOrClassDef;
1316             ClassSymbol previousClassSym = currentClassSym;
1317             try {
1318                 insideLambdaOrClassDef = true;
1319                 currentClassSym = classDecl.sym;
1320                 super.visitClassDef(classDecl);
1321             } finally {
1322                 insideLambdaOrClassDef = previousInsideLambdaOrClassDef;
1323                 currentClassSym = previousClassSym;
1324             }
1325         }
1326 
1327         private void reportPrologueError(JCTree tree, Symbol sym) {
1328             reportPrologueError(tree, sym, false);
1329         }
1330 
1331         private void reportPrologueError(JCTree tree, Symbol sym, boolean hasInit) {
1332             preview.checkSourceLevel(tree, Feature.FLEXIBLE_CONSTRUCTORS);
1333             if (mode != PrologueVisitorMode.WARNINGS_ONLY) {
1334                 if (hasInit) {
1335                     log.error(tree, Errors.CantAssignInitializedBeforeCtorCalled(sym));
1336                 } else {
1337                     log.error(tree, Errors.CantRefBeforeCtorCalled(sym));
1338                 }
1339             } else if (allowValueClasses) {
1340                 // issue lint warning
1341                 log.warning(tree, LintWarnings.WouldNotBeAllowedInPrologue(sym));
1342             }
1343         }
1344 
1345         @Override
1346         public void visitApply(JCMethodInvocation tree) {
1347             super.visitApply(tree);
1348             Name name = TreeInfo.name(tree.meth);
1349             boolean isConstructorCall = name == names._this || name == names._super;
1350             Symbol msym = TreeInfo.symbolFor(tree.meth);
1351             // is this an instance method call or an illegal constructor invocation like: `this.super()`?
1352             if (msym != null && // for erroneous invocations msym can be null, ignore those
1353                 (!isConstructorCall ||
1354                 isConstructorCall && tree.meth.hasTag(SELECT))) {
1355                 if (isEarlyReference(localEnv, tree.meth, msym))
1356                     reportPrologueError(tree.meth, msym);
1357             }
1358         }
1359 
1360         @Override
1361         public void visitIdent(JCIdent tree) {
1362             analyzeSymbol(tree);
1363         }
1364 
1365         boolean isIndexed = false;
1366 
1367         @Override
1368         public void visitIndexed(JCArrayAccess tree) {
1369             boolean previousIsIndexed = isIndexed;
1370             try {
1371                 isIndexed = true;
1372                 scan(tree.indexed);
1373             } finally {
1374                 isIndexed = previousIsIndexed;
1375             }
1376             scan(tree.index);
1377             if (mode == PrologueVisitorMode.SUPER_CONSTRUCTOR && isInstanceField(tree.indexed)) {
1378                 localProxyVarsGen.addFieldReadInPrologue(localEnv.enclMethod, TreeInfo.symbolFor(tree.indexed));
1379             }
1380         }
1381 
1382         @Override
1383         public void visitSelect(JCFieldAccess tree) {
1384             SelectScanner ss = new SelectScanner();
1385             ss.scan(tree);
1386             if (ss.scanLater == null) {
1387                 Symbol sym = TreeInfo.symbolFor(tree);
1388                 // if this is a field access
1389                 if (sym.kind == VAR && sym.owner.kind == TYP) {
1390                     // Type.super.field or super.field expressions are forbidden in early construction contexts
1391                     for (JCTree subtree : ss.selectorTrees) {
1392                         if (TreeInfo.isSuperOrSelectorDotSuper(subtree)) {
1393                             reportPrologueError(tree, sym);
1394                             return;
1395                         } else if (mode == PrologueVisitorMode.THIS_CONSTRUCTOR &&
1396                                 TreeInfo.isThisOrSelectorDotThis(subtree) &&
1397                                 TreeInfo.isExplicitThisReference(
1398                                         types,
1399                                         (ClassType)localEnv.enclClass.sym.type,
1400                                         subtree)) {
1401                             reportPrologueError(tree, sym);
1402                             return;
1403                         }
1404                     }
1405                 }
1406                 analyzeSymbol(tree);
1407             } else {
1408                 boolean prevLhs = isInLHS;
1409                 try {
1410                     isInLHS = false;
1411                     scan(ss.scanLater);
1412                 } finally {
1413                     isInLHS = prevLhs;
1414                 }
1415             }
1416             if (mode == PrologueVisitorMode.SUPER_CONSTRUCTOR) {
1417                 for (JCTree subtree : ss.selectorTrees) {
1418                     if (isInstanceField(subtree)) {
1419                         // we need to add a proxy for this one
1420                         localProxyVarsGen.addFieldReadInPrologue(localEnv.enclMethod, TreeInfo.symbolFor(subtree));
1421                     }
1422                 }
1423             }
1424         }
1425 
1426         private boolean isInstanceField(JCTree tree) {
1427             Symbol sym = TreeInfo.symbolFor(tree);
1428             return (sym != null &&
1429                     !sym.isStatic() &&
1430                     sym.kind == VAR &&
1431                     sym.owner.kind == TYP &&
1432                     sym.name != names._this &&
1433                     sym.name != names._super &&
1434                     isEarlyReference(localEnv, tree, sym));
1435         }
1436 
1437         @Override
1438         public void visitNewClass(JCNewClass tree) {
1439             super.visitNewClass(tree);
1440             checkNewClassAndMethRefs(tree, tree.type);
1441         }
1442 
1443         @Override
1444         public void visitReference(JCMemberReference tree) {
1445             super.visitReference(tree);
1446             if (tree.getMode() == JCMemberReference.ReferenceMode.NEW) {
1447                 checkNewClassAndMethRefs(tree, tree.expr.type);
1448             }
1449         }
1450 
1451         void checkNewClassAndMethRefs(JCTree tree, Type t) {
1452             if (t.tsym.isEnclosedBy(localEnv.enclClass.sym) &&
1453                     !t.tsym.isStatic() &&
1454                     !t.tsym.isDirectlyOrIndirectlyLocal()) {
1455                 reportPrologueError(tree, t.getEnclosingType().tsym);
1456             }
1457         }
1458 
1459         /* if a symbol is in the LHS of an assignment expression we won't consider it as a candidate
1460          * for a proxy local variable later on
1461          */
1462         boolean isInLHS = false;
1463 
1464         @Override
1465         public void visitAssign(JCAssign tree) {
1466             boolean previousIsInLHS = isInLHS;
1467             try {
1468                 isInLHS = true;
1469                 scan(tree.lhs);
1470             } finally {
1471                 isInLHS = previousIsInLHS;
1472             }
1473             scan(tree.rhs);
1474         }
1475 
1476         @Override
1477         public void visitMethodDef(JCMethodDecl tree) {
1478             // ignore any declarative part, mainly to avoid scanning receiver parameters
1479             scan(tree.body);
1480         }
1481 
1482         void analyzeSymbol(JCTree tree) {
1483             Symbol sym = TreeInfo.symbolFor(tree);
1484             // make sure that there is a symbol and it is not static
1485             if (sym == null || sym.isStatic()) {
1486                 return;
1487             }
1488             if (isInLHS && !insideLambdaOrClassDef) {
1489                 // Check instance field assignments that appear in constructor prologues
1490                 if (isEarlyReference(localEnv, tree, sym)) {
1491                     // Field may not be inherited from a superclass
1492                     if (sym.owner != localEnv.enclClass.sym) {
1493                         reportPrologueError(tree, sym);
1494                         return;
1495                     }
1496                     // Field may not have an initializer
1497                     if ((sym.flags() & HASINIT) != 0) {
1498                         if (!localEnv.enclClass.sym.isValueClass() || !sym.type.hasTag(ARRAY) || !isIndexed) {
1499                             reportPrologueError(tree, sym, true);
1500                         }
1501                         return;
1502                     }
1503                     // cant reference an instance field before a this constructor
1504                     if (allowValueClasses && mode == PrologueVisitorMode.THIS_CONSTRUCTOR) {
1505                         reportPrologueError(tree, sym);
1506                         return;
1507                     }
1508                 }
1509                 return;
1510             }
1511             tree = TreeInfo.skipParens(tree);
1512             if (sym.kind == VAR && sym.owner.kind == TYP) {
1513                 if (sym.name == names._this || sym.name == names._super) {
1514                     // are we seeing something like `this` or `CurrentClass.this` or `SuperClass.super::foo`?
1515                     if (TreeInfo.isExplicitThisReference(
1516                             types,
1517                             (ClassType)localEnv.enclClass.sym.type,
1518                             tree)) {
1519                         reportPrologueError(tree, sym);
1520                     }
1521                 } else if (sym.kind == VAR && sym.owner.kind == TYP) { // now fields only
1522                     if (sym.owner != localEnv.enclClass.sym) {
1523                         if (localEnv.enclClass.sym.isSubClass(sym.owner, types) &&
1524                                 sym.isInheritedIn(localEnv.enclClass.sym, types)) {
1525                             /* if we are dealing with a field that doesn't belong to the current class, but the
1526                              * field is inherited, this is an error. Unless, the super class is also an outer
1527                              * class and the field's qualifier refers to the outer class
1528                              */
1529                             if (tree.hasTag(IDENT) ||
1530                                 TreeInfo.isExplicitThisReference(
1531                                         types,
1532                                         (ClassType)localEnv.enclClass.sym.type,
1533                                         ((JCFieldAccess)tree).selected)) {
1534                                 reportPrologueError(tree, sym);
1535                             }
1536                         }
1537                     } else if (isEarlyReference(localEnv, tree, sym)) {
1538                         /* now this is a `proper` instance field of the current class
1539                          * references to fields of identity classes which happen to have initializers are
1540                          * not allowed in the prologue.
1541                          * But it is OK for a field with initializer to refer to another field with initializer,
1542                          * so no warning or error if we are analyzing a field initializer.
1543                          */
1544                         if (insideLambdaOrClassDef ||
1545                             (!localEnv.enclClass.sym.isValueClass() &&
1546                              (sym.flags_field & HASINIT) != 0 &&
1547                              !isInitializer))
1548                             reportPrologueError(tree, sym);
1549                         // we will need to generate a proxy for this field later on
1550                         if (!isInLHS) {
1551                             if (!allowValueClasses) {
1552                                 reportPrologueError(tree, sym);
1553                             } else {
1554                                 if (mode == PrologueVisitorMode.THIS_CONSTRUCTOR) {
1555                                     reportPrologueError(tree, sym);
1556                                 } else if (mode == PrologueVisitorMode.SUPER_CONSTRUCTOR && isInstanceField(tree)) {
1557                                     localProxyVarsGen.addFieldReadInPrologue(localEnv.enclMethod, sym);
1558                                 }
1559                                 /* we do nothing in warnings only mode, as in that mode we are simulating what
1560                                  * the compiler would do in case the constructor code would be in the prologue
1561                                  * phase
1562                                  */
1563                             }
1564                         }
1565                     }
1566                 }
1567             }
1568         }
1569 
1570         /**
1571          * Determine if the symbol appearance constitutes an early reference to the current class.
1572          *
1573          * <p>
1574          * This means the symbol is an instance field, or method, of the current class and it appears
1575          * in an early initialization context of it (i.e., one of its constructor prologues).
1576          *
1577          * @param env    The current environment
1578          * @param tree   the AST referencing the variable
1579          * @param sym    The symbol
1580          */
1581         private boolean isEarlyReference(Env<AttrContext> env, JCTree tree, Symbol sym) {
1582             if ((sym.kind == VAR || sym.kind == MTH) &&
1583                     sym.isMemberOf(env.enclClass.sym, types) &&
1584                     ((sym.flags() & STATIC) == 0 ||
1585                     (sym.kind == MTH && tree instanceof JCFieldAccess))) {
1586                 // Allow "Foo.this.x" when "Foo" is (also) an outer class, as this refers to the outer instance
1587                 if (tree instanceof JCFieldAccess fa) {
1588                     return TreeInfo.isExplicitThisReference(types, (ClassType)env.enclClass.type, fa.selected);
1589                 } else if (currentClassSym != env.enclClass.sym) {
1590                     /* so we are inside a class, CI, in the prologue of an outer class, CO, and the symbol being
1591                      * analyzed has no qualifier. So if the symbol is a member of CI the reference is allowed,
1592                      * otherwise it is not.
1593                      * It could be that the reference to CI's member happens inside CI's own prologue, but that
1594                      * will be checked separately, when CI's prologue is analyzed.
1595                      */
1596                     return !sym.isMemberOf(currentClassSym, types);
1597                 }
1598                 return true;
1599             }
1600             return false;
1601         }
1602 
1603         /* scanner for a select expression, anything that is not a select or identifier
1604          * will be stored for further analysis
1605          */
1606         class SelectScanner extends DeferredAttr.FilterScanner {
1607             JCTree scanLater;
1608             java.util.List<JCTree> selectorTrees = new ArrayList<>();
1609 
1610             SelectScanner() {
1611                 super(Set.of(IDENT, SELECT, PARENS));
1612             }
1613 
1614             @Override
1615             public void visitSelect(JCFieldAccess tree) {
1616                 super.visitSelect(tree);
1617                 selectorTrees.add(tree.selected);
1618             }
1619 
1620             @Override
1621             void skip(JCTree tree) {
1622                 scanLater = tree;
1623             }
1624         }
1625     }
1626 
1627     public void visitVarDef(JCVariableDecl tree) {
1628         // Local variables have not been entered yet, so we need to do it now:
1629         if (env.info.scope.owner.kind == MTH || env.info.scope.owner.kind == VAR) {
1630             if (tree.sym != null) {
1631                 // parameters have already been entered
1632                 env.info.scope.enter(tree.sym);
1633             } else {
1634                 if (tree.isImplicitlyTyped() && (tree.getModifiers().flags & PARAMETER) == 0) {
1635                     if (tree.init == null) {
1636                         //cannot use 'var' without initializer
1637                         log.error(tree, Errors.CantInferLocalVarType(tree.name, Fragments.LocalMissingInit));
1638                         tree.vartype = make.at(tree.pos()).Erroneous();
1639                     } else {
1640                         Fragment msg = canInferLocalVarType(tree);
1641                         if (msg != null) {
1642                             //cannot use 'var' with initializer which require an explicit target
1643                             //(e.g. lambda, method reference, array initializer).
1644                             log.error(tree, Errors.CantInferLocalVarType(tree.name, msg));
1645                             tree.vartype = make.at(tree.pos()).Erroneous();
1646                         }
1647                     }
1648                 }
1649                 try {
1650                     annotate.blockAnnotations();
1651                     memberEnter.memberEnter(tree, env);
1652                 } finally {
1653                     annotate.unblockAnnotations();
1654                 }
1655             }
1656         } else {
1657             doQueueScanTreeAndTypeAnnotateForVarInit(tree, env);
1658         }
1659 
1660         VarSymbol v = tree.sym;
1661         Lint lint = env.info.lint.augment(v);
1662         Lint prevLint = chk.setLint(lint);
1663 
1664         // Check that the variable's declared type is well-formed.
1665         boolean isImplicitLambdaParameter = env.tree.hasTag(LAMBDA) &&
1666                 ((JCLambda)env.tree).paramKind == JCLambda.ParameterKind.IMPLICIT &&
1667                 (tree.sym.flags() & PARAMETER) != 0;
1668         chk.validate(tree.vartype, env, !isImplicitLambdaParameter && !tree.isImplicitlyTyped());
1669 
1670         try {
1671             v.getConstValue(); // ensure compile-time constant initializer is evaluated
1672             chk.checkDeprecatedAnnotation(tree.pos(), v);
1673 
1674             if (tree.init != null) {
1675                 Env<AttrContext> initEnv = memberEnter.initEnv(tree, env);
1676                 if ((v.flags_field & FINAL) == 0 ||
1677                     !memberEnter.needsLazyConstValue(tree.init)) {
1678                     // Not a compile-time constant
1679                     // Attribute initializer in a new environment
1680                     // with the declared variable as owner.
1681                     // Check that initializer conforms to variable's declared type.
1682                     initEnv.info.lint = lint;
1683                     // In order to catch self-references, we set the variable's
1684                     // declaration position to maximal possible value, effectively
1685                     // marking the variable as undefined.
1686                     initEnv.info.enclVar = v;
1687                     boolean previousCtorPrologue = initEnv.info.ctorPrologue;
1688                     try {
1689                         if (v.owner.kind == TYP && !v.isStatic() && v.isStrict()) {
1690                             // strict instance initializer in a value class
1691                             initEnv.info.ctorPrologue = true;
1692                         }
1693                         attribExpr(tree.init, initEnv, v.type);
1694                         if (tree.isImplicitlyTyped()) {
1695                             //fixup local variable type
1696                             v.type = chk.checkLocalVarType(tree, tree.init.type, tree.name);
1697                         }
1698                     } finally {
1699                         initEnv.info.ctorPrologue = previousCtorPrologue;
1700                     }
1701                 }
1702                 if (allowValueClasses && v.owner.kind == TYP && !v.isStatic()) {
1703                     // strict field initializers are inlined in constructor's prologues
1704                     CtorPrologueVisitor ctorPrologueVisitor = new CtorPrologueVisitor(initEnv,
1705                             !v.isStrict() ? PrologueVisitorMode.WARNINGS_ONLY : PrologueVisitorMode.SUPER_CONSTRUCTOR,
1706                             true);
1707                     ctorPrologueVisitor.scan(tree.init);
1708                 }
1709                 if (tree.isImplicitlyTyped()) {
1710                     setSyntheticVariableType(tree, v.type);
1711                 }
1712             }
1713             result = tree.type = v.type;
1714             if (env.enclClass.sym.isRecord() && tree.sym.owner.kind == TYP && !v.isStatic()) {
1715                 if (isNonArgsMethodInObject(v.name)) {
1716                     log.error(tree, Errors.IllegalRecordComponentName(v));
1717                 }
1718             }
1719             chk.checkRequiresIdentity(tree, env.info.lint);
1720         }
1721         finally {
1722             chk.setLint(prevLint);
1723         }
1724     }
1725 
1726     private void doQueueScanTreeAndTypeAnnotateForVarInit(JCVariableDecl tree, Env<AttrContext> env) {
1727         if (tree.init != null &&
1728             (tree.mods.flags & Flags.FIELD_INIT_TYPE_ANNOTATIONS_QUEUED) == 0 &&
1729             env.info.scope.owner.kind != MTH && env.info.scope.owner.kind != VAR) {
1730             tree.mods.flags |= Flags.FIELD_INIT_TYPE_ANNOTATIONS_QUEUED;
1731             // Field initializer expression need to be entered.
1732             annotate.queueScanTreeAndTypeAnnotate(tree.init, env, tree.sym);
1733             annotate.flush();
1734         }
1735     }
1736 
1737     private boolean isNonArgsMethodInObject(Name name) {
1738         for (Symbol s : syms.objectType.tsym.members().getSymbolsByName(name, s -> s.kind == MTH)) {
1739             if (s.type.getParameterTypes().isEmpty()) {
1740                 return true;
1741             }
1742         }
1743         return false;
1744     }
1745 
1746     Fragment canInferLocalVarType(JCVariableDecl tree) {
1747         LocalInitScanner lis = new LocalInitScanner();
1748         lis.scan(tree.init);
1749         return lis.badInferenceMsg;
1750     }
1751 
1752     static class LocalInitScanner extends TreeScanner {
1753         Fragment badInferenceMsg = null;
1754         boolean needsTarget = true;
1755 
1756         @Override
1757         public void visitNewArray(JCNewArray tree) {
1758             if (tree.elemtype == null && needsTarget) {
1759                 badInferenceMsg = Fragments.LocalArrayMissingTarget;
1760             }
1761         }
1762 
1763         @Override
1764         public void visitLambda(JCLambda tree) {
1765             if (needsTarget) {
1766                 badInferenceMsg = Fragments.LocalLambdaMissingTarget;
1767             }
1768         }
1769 
1770         @Override
1771         public void visitTypeCast(JCTypeCast tree) {
1772             boolean prevNeedsTarget = needsTarget;
1773             try {
1774                 needsTarget = false;
1775                 super.visitTypeCast(tree);
1776             } finally {
1777                 needsTarget = prevNeedsTarget;
1778             }
1779         }
1780 
1781         @Override
1782         public void visitReference(JCMemberReference tree) {
1783             if (needsTarget) {
1784                 badInferenceMsg = Fragments.LocalMrefMissingTarget;
1785             }
1786         }
1787 
1788         @Override
1789         public void visitNewClass(JCNewClass tree) {
1790             boolean prevNeedsTarget = needsTarget;
1791             try {
1792                 needsTarget = false;
1793                 super.visitNewClass(tree);
1794             } finally {
1795                 needsTarget = prevNeedsTarget;
1796             }
1797         }
1798 
1799         @Override
1800         public void visitApply(JCMethodInvocation tree) {
1801             boolean prevNeedsTarget = needsTarget;
1802             try {
1803                 needsTarget = false;
1804                 super.visitApply(tree);
1805             } finally {
1806                 needsTarget = prevNeedsTarget;
1807             }
1808         }
1809     }
1810 
1811     public void visitSkip(JCSkip tree) {
1812         result = null;
1813     }
1814 
1815     public void visitBlock(JCBlock tree) {
1816         if (env.info.scope.owner.kind == TYP || env.info.scope.owner.kind == ERR) {
1817             // Block is a static or instance initializer;
1818             // let the owner of the environment be a freshly
1819             // created BLOCK-method.
1820             Symbol fakeOwner =
1821                 new MethodSymbol(tree.flags | BLOCK |
1822                     env.info.scope.owner.flags() & STRICTFP, names.empty, initBlockType,
1823                     env.info.scope.owner);
1824             final Env<AttrContext> localEnv =
1825                 env.dup(tree, env.info.dup(env.info.scope.dupUnshared(fakeOwner)));
1826 
1827             if ((tree.flags & STATIC) != 0) {
1828                 localEnv.info.staticLevel++;
1829             } else {
1830                 localEnv.info.instanceInitializerBlock = true;
1831             }
1832             // Attribute all type annotations in the block
1833             annotate.queueScanTreeAndTypeAnnotate(tree, localEnv, localEnv.info.scope.owner);
1834             annotate.flush();
1835             attribStats(tree.stats, localEnv);
1836 
1837             {
1838                 // Store init and clinit type annotations with the ClassSymbol
1839                 // to allow output in Gen.normalizeDefs.
1840                 ClassSymbol cs = (ClassSymbol)env.info.scope.owner;
1841                 List<Attribute.TypeCompound> tas = localEnv.info.scope.owner.getRawTypeAttributes();
1842                 if ((tree.flags & STATIC) != 0) {
1843                     cs.appendClassInitTypeAttributes(tas);
1844                 } else {
1845                     cs.appendInitTypeAttributes(tas);
1846                 }
1847             }
1848         } else {
1849             // Create a new local environment with a local scope.
1850             Env<AttrContext> localEnv =
1851                 env.dup(tree, env.info.dup(env.info.scope.dup()));
1852             try {
1853                 attribStats(tree.stats, localEnv);
1854             } finally {
1855                 localEnv.info.scope.leave();
1856             }
1857         }
1858         result = null;
1859     }
1860 
1861     public void visitDoLoop(JCDoWhileLoop tree) {
1862         attribStat(tree.body, env.dup(tree));
1863         attribExpr(tree.cond, env, syms.booleanType);
1864         handleLoopConditionBindings(matchBindings, tree, tree.body);
1865         result = null;
1866     }
1867 
1868     public void visitWhileLoop(JCWhileLoop tree) {
1869         attribExpr(tree.cond, env, syms.booleanType);
1870         MatchBindings condBindings = matchBindings;
1871         // include condition's bindings when true in the body:
1872         Env<AttrContext> whileEnv = bindingEnv(env, condBindings.bindingsWhenTrue);
1873         try {
1874             attribStat(tree.body, whileEnv.dup(tree));
1875         } finally {
1876             whileEnv.info.scope.leave();
1877         }
1878         handleLoopConditionBindings(condBindings, tree, tree.body);
1879         result = null;
1880     }
1881 
1882     public void visitForLoop(JCForLoop tree) {
1883         Env<AttrContext> loopEnv =
1884             env.dup(env.tree, env.info.dup(env.info.scope.dup()));
1885         MatchBindings condBindings = MatchBindingsComputer.EMPTY;
1886         try {
1887             attribStats(tree.init, loopEnv);
1888             if (tree.cond != null) {
1889                 attribExpr(tree.cond, loopEnv, syms.booleanType);
1890                 // include condition's bindings when true in the body and step:
1891                 condBindings = matchBindings;
1892             }
1893             Env<AttrContext> bodyEnv = bindingEnv(loopEnv, condBindings.bindingsWhenTrue);
1894             try {
1895                 bodyEnv.tree = tree; // before, we were not in loop!
1896                 attribStats(tree.step, bodyEnv);
1897                 attribStat(tree.body, bodyEnv);
1898             } finally {
1899                 bodyEnv.info.scope.leave();
1900             }
1901             result = null;
1902         }
1903         finally {
1904             loopEnv.info.scope.leave();
1905         }
1906         handleLoopConditionBindings(condBindings, tree, tree.body);
1907     }
1908 
1909     /**
1910      * Include condition's bindings when false after the loop, if cannot get out of the loop
1911      */
1912     private void handleLoopConditionBindings(MatchBindings condBindings,
1913                                              JCStatement loop,
1914                                              JCStatement loopBody) {
1915         if (condBindings.bindingsWhenFalse.nonEmpty() &&
1916             !breaksTo(env, loop, loopBody)) {
1917             addBindings2Scope(loop, condBindings.bindingsWhenFalse);
1918         }
1919     }
1920 
1921     private boolean breaksTo(Env<AttrContext> env, JCTree loop, JCTree body) {
1922         preFlow(body);
1923         return flow.breaksToTree(env, loop, body, make);
1924     }
1925 
1926     /**
1927      * Add given bindings to the current scope, unless there's a break to
1928      * an immediately enclosing labeled statement.
1929      */
1930     private void addBindings2Scope(JCStatement introducingStatement,
1931                                    List<BindingSymbol> bindings) {
1932         if (bindings.isEmpty()) {
1933             return ;
1934         }
1935 
1936         var searchEnv = env;
1937         while (searchEnv.tree instanceof JCLabeledStatement labeled &&
1938                labeled.body == introducingStatement) {
1939             if (breaksTo(env, labeled, labeled.body)) {
1940                 //breaking to an immediately enclosing labeled statement
1941                 return ;
1942             }
1943             searchEnv = searchEnv.next;
1944             introducingStatement = labeled;
1945         }
1946 
1947         //include condition's body when false after the while, if cannot get out of the loop
1948         bindings.forEach(env.info.scope::enter);
1949         bindings.forEach(BindingSymbol::preserveBinding);
1950     }
1951 
1952     public void visitForeachLoop(JCEnhancedForLoop tree) {
1953         Env<AttrContext> loopEnv =
1954             env.dup(env.tree, env.info.dup(env.info.scope.dup()));
1955         try {
1956             //the Formal Parameter of a for-each loop is not in the scope when
1957             //attributing the for-each expression; we mimic this by attributing
1958             //the for-each expression first (against original scope).
1959             Type exprType = types.cvarUpperBound(attribExpr(tree.expr, loopEnv));
1960             chk.checkNonVoid(tree.pos(), exprType);
1961             Type elemtype = types.elemtype(exprType); // perhaps expr is an array?
1962             if (elemtype == null) {
1963                 // or perhaps expr implements Iterable<T>?
1964                 Type base = types.asSuper(exprType, syms.iterableType.tsym);
1965                 if (base == null) {
1966                     log.error(tree.expr.pos(),
1967                               Errors.ForeachNotApplicableToType(exprType,
1968                                                                 Fragments.TypeReqArrayOrIterable));
1969                     elemtype = types.createErrorType(exprType);
1970                 } else {
1971                     List<Type> iterableParams = base.allparams();
1972                     elemtype = iterableParams.isEmpty()
1973                         ? syms.objectType
1974                         : types.wildUpperBound(iterableParams.head);
1975 
1976                     // Check the return type of the method iterator().
1977                     // This is the bare minimum we need to verify to make sure code generation doesn't crash.
1978                     Symbol iterSymbol = rs.resolveInternalMethod(tree.pos(),
1979                             loopEnv, types.skipTypeVars(exprType, false), names.iterator, List.nil(), List.nil());
1980                     if (types.asSuper(iterSymbol.type.getReturnType(), syms.iteratorType.tsym) == null) {
1981                         log.error(tree.pos(),
1982                                 Errors.ForeachNotApplicableToType(exprType, Fragments.TypeReqArrayOrIterable));
1983                     }
1984                 }
1985             }
1986             if (tree.var.isImplicitlyTyped()) {
1987                 Type inferredType = chk.checkLocalVarType(tree.var, elemtype, tree.var.name);
1988                 setSyntheticVariableType(tree.var, inferredType);
1989             }
1990             attribStat(tree.var, loopEnv);
1991             chk.checkType(tree.expr.pos(), elemtype, tree.var.sym.type);
1992             loopEnv.tree = tree; // before, we were not in loop!
1993             attribStat(tree.body, loopEnv);
1994             result = null;
1995         }
1996         finally {
1997             loopEnv.info.scope.leave();
1998         }
1999     }
2000 
2001     public void visitLabelled(JCLabeledStatement tree) {
2002         // Check that label is not used in an enclosing statement
2003         Env<AttrContext> env1 = env;
2004         while (env1 != null && !env1.tree.hasTag(CLASSDEF)) {
2005             if (env1.tree.hasTag(LABELLED) &&
2006                 ((JCLabeledStatement) env1.tree).label == tree.label) {
2007                 log.error(tree.pos(),
2008                           Errors.LabelAlreadyInUse(tree.label));
2009                 break;
2010             }
2011             env1 = env1.next;
2012         }
2013 
2014         attribStat(tree.body, env.dup(tree));
2015         result = null;
2016     }
2017 
2018     public void visitSwitch(JCSwitch tree) {
2019         handleSwitch(tree, tree.selector, tree.cases, (c, caseEnv) -> {
2020             attribStats(c.stats, caseEnv);
2021         });
2022         result = null;
2023     }
2024 
2025     public void visitSwitchExpression(JCSwitchExpression tree) {
2026         boolean wrongContext = false;
2027 
2028         tree.polyKind = (pt().hasTag(NONE) && pt() != Type.recoveryType && pt() != Infer.anyPoly) ?
2029                 PolyKind.STANDALONE : PolyKind.POLY;
2030 
2031         if (tree.polyKind == PolyKind.POLY && resultInfo.pt.hasTag(VOID)) {
2032             //this means we are returning a poly conditional from void-compatible lambda expression
2033             resultInfo.checkContext.report(tree, diags.fragment(Fragments.SwitchExpressionTargetCantBeVoid));
2034             resultInfo = recoveryInfo;
2035             wrongContext = true;
2036         }
2037 
2038         ResultInfo condInfo = tree.polyKind == PolyKind.STANDALONE ?
2039                 unknownExprInfo :
2040                 resultInfo.dup(switchExpressionContext(resultInfo.checkContext));
2041 
2042         ListBuffer<DiagnosticPosition> caseTypePositions = new ListBuffer<>();
2043         ListBuffer<Type> caseTypes = new ListBuffer<>();
2044 
2045         handleSwitch(tree, tree.selector, tree.cases, (c, caseEnv) -> {
2046             caseEnv.info.yieldResult = condInfo;
2047             attribStats(c.stats, caseEnv);
2048             new TreeScanner() {
2049                 @Override
2050                 public void visitYield(JCYield brk) {
2051                     if (brk.target == tree) {
2052                         caseTypePositions.append(brk.value != null ? brk.value.pos() : brk.pos());
2053                         caseTypes.append(brk.value != null ? brk.value.type : syms.errType);
2054                     }
2055                     super.visitYield(brk);
2056                 }
2057 
2058                 @Override public void visitClassDef(JCClassDecl tree) {}
2059                 @Override public void visitLambda(JCLambda tree) {}
2060             }.scan(c.stats);
2061         });
2062 
2063         if (tree.cases.isEmpty()) {
2064             log.error(tree.pos(),
2065                       Errors.SwitchExpressionEmpty);
2066         } else if (caseTypes.isEmpty()) {
2067             log.error(tree.pos(),
2068                       Errors.SwitchExpressionNoResultExpressions);
2069         }
2070 
2071         Type owntype = (tree.polyKind == PolyKind.STANDALONE) ? condType(caseTypePositions.toList(), caseTypes.toList()) : pt();
2072 
2073         result = tree.type = wrongContext? types.createErrorType(pt()) : check(tree, owntype, KindSelector.VAL, resultInfo);
2074     }
2075     //where:
2076         CheckContext switchExpressionContext(CheckContext checkContext) {
2077             return new Check.NestedCheckContext(checkContext) {
2078                 //this will use enclosing check context to check compatibility of
2079                 //subexpression against target type; if we are in a method check context,
2080                 //depending on whether boxing is allowed, we could have incompatibilities
2081                 @Override
2082                 public void report(DiagnosticPosition pos, JCDiagnostic details) {
2083                     enclosingContext.report(pos, diags.fragment(Fragments.IncompatibleTypeInSwitchExpression(details)));
2084                 }
2085             };
2086         }
2087 
2088     private void handleSwitch(JCTree switchTree,
2089                               JCExpression selector,
2090                               List<JCCase> cases,
2091                               BiConsumer<JCCase, Env<AttrContext>> attribCase) {
2092         Type seltype = attribExpr(selector, env);
2093         Type seltypeUnboxed = types.unboxedTypeOrType(seltype);
2094 
2095         Env<AttrContext> switchEnv =
2096             env.dup(switchTree, env.info.dup(env.info.scope.dup()));
2097 
2098         try {
2099             boolean enumSwitch = (seltype.tsym.flags() & Flags.ENUM) != 0;
2100             boolean stringSwitch = types.isSameType(seltype, syms.stringType);
2101             boolean booleanSwitch = types.isSameType(seltypeUnboxed, syms.booleanType);
2102             boolean errorEnumSwitch = TreeInfo.isErrorEnumSwitch(selector, cases);
2103             boolean intSwitch = types.isAssignable(seltype, syms.intType);
2104             boolean patternSwitch;
2105             if (seltype.isPrimitive() && !intSwitch) {
2106                 preview.checkSourceLevel(selector.pos(), Feature.PRIMITIVE_PATTERNS);
2107                 patternSwitch = true;
2108             }
2109             if (!enumSwitch && !stringSwitch && !errorEnumSwitch &&
2110                 !intSwitch) {
2111                 preview.checkSourceLevel(selector.pos(), Feature.PATTERN_SWITCH);
2112                 patternSwitch = true;
2113             } else {
2114                 patternSwitch = cases.stream()
2115                                      .flatMap(c -> c.labels.stream())
2116                                      .anyMatch(l -> l.hasTag(PATTERNCASELABEL) ||
2117                                                     TreeInfo.isNullCaseLabel(l));
2118             }
2119 
2120             // Attribute all cases and
2121             // check that there are no duplicate case labels or default clauses.
2122             Set<Object> constants = new HashSet<>(); // The set of case constants.
2123             boolean hasDefault = false;           // Is there a default label?
2124             boolean hasUnconditionalPattern = false; // Is there a unconditional pattern?
2125             boolean lastPatternErroneous = false; // Has the last pattern erroneous type?
2126             boolean hasNullPattern = false;       // Is there a null pattern?
2127             CaseTree.CaseKind caseKind = null;
2128             boolean wasError = false;
2129             JCCaseLabel unconditionalCaseLabel = null;
2130             for (List<JCCase> l = cases; l.nonEmpty(); l = l.tail) {
2131                 JCCase c = l.head;
2132                 if (caseKind == null) {
2133                     caseKind = c.caseKind;
2134                 } else if (caseKind != c.caseKind && !wasError) {
2135                     log.error(c.pos(),
2136                               Errors.SwitchMixingCaseTypes);
2137                     wasError = true;
2138                 }
2139                 MatchBindings currentBindings = null;
2140                 MatchBindings guardBindings = null;
2141                 for (List<JCCaseLabel> labels = c.labels; labels.nonEmpty(); labels = labels.tail) {
2142                     JCCaseLabel label = labels.head;
2143                     if (label instanceof JCConstantCaseLabel constLabel) {
2144                         JCExpression expr = constLabel.expr;
2145                         if (TreeInfo.isNull(expr)) {
2146                             preview.checkSourceLevel(expr.pos(), Feature.CASE_NULL);
2147                             if (hasNullPattern) {
2148                                 log.error(label.pos(), Errors.DuplicateCaseLabel);
2149                             }
2150                             hasNullPattern = true;
2151                             attribExpr(expr, switchEnv, seltype);
2152                             matchBindings = new MatchBindings(matchBindings.bindingsWhenTrue, matchBindings.bindingsWhenFalse, true);
2153                         } else if (enumSwitch) {
2154                             Symbol sym = enumConstant(expr, seltype);
2155                             if (sym == null) {
2156                                 if (allowPatternSwitch) {
2157                                     attribTree(expr, switchEnv, caseLabelResultInfo(seltype));
2158                                     Symbol enumSym = TreeInfo.symbol(expr);
2159                                     if (enumSym == null || !enumSym.isEnum() || enumSym.kind != VAR) {
2160                                         log.error(expr.pos(), Errors.EnumLabelMustBeEnumConstant);
2161                                     } else if (!constants.add(enumSym)) {
2162                                         log.error(label.pos(), Errors.DuplicateCaseLabel);
2163                                     }
2164                                 } else {
2165                                     log.error(expr.pos(), Errors.EnumLabelMustBeUnqualifiedEnum);
2166                                 }
2167                             } else if (!constants.add(sym)) {
2168                                 log.error(label.pos(), Errors.DuplicateCaseLabel);
2169                             }
2170                         } else if (errorEnumSwitch) {
2171                             //error recovery: the selector is erroneous, and all the case labels
2172                             //are identifiers. This could be an enum switch - don't report resolve
2173                             //error for the case label:
2174                             var prevResolveHelper = rs.basicLogResolveHelper;
2175                             try {
2176                                 rs.basicLogResolveHelper = rs.silentLogResolveHelper;
2177                                 attribExpr(expr, switchEnv, seltype);
2178                             } finally {
2179                                 rs.basicLogResolveHelper = prevResolveHelper;
2180                             }
2181                         } else {
2182                             Type pattype = attribTree(expr, switchEnv, caseLabelResultInfo(seltype));
2183                             if (!pattype.hasTag(ERROR)) {
2184                                 if (pattype.constValue() == null) {
2185                                     Symbol s = TreeInfo.symbol(expr);
2186                                     if (s != null && s.kind == TYP) {
2187                                         log.error(expr.pos(),
2188                                                   Errors.PatternExpected);
2189                                     } else if (s == null || !s.isEnum()) {
2190                                         log.error(expr.pos(),
2191                                                   (stringSwitch ? Errors.StringConstReq
2192                                                                 : intSwitch ? Errors.ConstExprReq
2193                                                                             : Errors.PatternOrEnumReq));
2194                                     } else if (!constants.add(s)) {
2195                                         log.error(label.pos(), Errors.DuplicateCaseLabel);
2196                                     }
2197                                 }
2198                                 else {
2199                                     boolean isLongFloatDoubleOrBooleanConstant =
2200                                             pattype.getTag().isInSuperClassesOf(LONG) || pattype.getTag().equals(BOOLEAN);
2201                                     if (isLongFloatDoubleOrBooleanConstant) {
2202                                         preview.checkSourceLevel(label.pos(), Feature.PRIMITIVE_PATTERNS);
2203                                     }
2204                                     if (!stringSwitch && !intSwitch && !(isLongFloatDoubleOrBooleanConstant && types.isSameType(seltypeUnboxed, pattype))) {
2205                                         log.error(label.pos(), Errors.ConstantLabelNotCompatible(pattype, seltype));
2206                                     } else if (!constants.add(pattype.constValue())) {
2207                                         log.error(c.pos(), Errors.DuplicateCaseLabel);
2208                                     }
2209                                 }
2210                             }
2211                         }
2212                     } else if (label instanceof JCDefaultCaseLabel def) {
2213                         if (hasDefault) {
2214                             log.error(label.pos(), Errors.DuplicateDefaultLabel);
2215                         } else if (hasUnconditionalPattern) {
2216                             log.error(label.pos(), Errors.UnconditionalPatternAndDefault);
2217                         }  else if (booleanSwitch && constants.containsAll(Set.of(0, 1))) {
2218                             log.error(label.pos(), Errors.DefaultAndBothBooleanValues);
2219                         }
2220                         hasDefault = true;
2221                         matchBindings = MatchBindingsComputer.EMPTY;
2222                     } else if (label instanceof JCPatternCaseLabel patternlabel) {
2223                         //pattern
2224                         JCPattern pat = patternlabel.pat;
2225                         attribExpr(pat, switchEnv, seltype);
2226                         Type primaryType = TreeInfo.primaryPatternType(pat);
2227 
2228                         if (primaryType.isPrimitive()) {
2229                             preview.checkSourceLevel(pat.pos(), Feature.PRIMITIVE_PATTERNS);
2230                         } else if (!primaryType.hasTag(TYPEVAR)) {
2231                             primaryType = chk.checkClassOrArrayType(pat.pos(), primaryType);
2232                         }
2233                         checkCastablePattern(pat.pos(), seltype, primaryType);
2234                         Type patternType = types.erasure(primaryType);
2235                         JCExpression guard = c.guard;
2236                         if (guardBindings == null && guard != null) {
2237                             MatchBindings afterPattern = matchBindings;
2238                             Env<AttrContext> bodyEnv = bindingEnv(switchEnv, matchBindings.bindingsWhenTrue);
2239                             try {
2240                                 attribExpr(guard, bodyEnv, syms.booleanType);
2241                             } finally {
2242                                 bodyEnv.info.scope.leave();
2243                             }
2244 
2245                             guardBindings = matchBindings;
2246                             matchBindings = afterPattern;
2247 
2248                             if (TreeInfo.isBooleanWithValue(guard, 0)) {
2249                                 log.error(guard.pos(), Errors.GuardHasConstantExpressionFalse);
2250                             }
2251                         }
2252                         boolean unguarded = TreeInfo.unguardedCase(c) && !pat.hasTag(RECORDPATTERN);
2253                         boolean unconditional =
2254                                 unguarded &&
2255                                 !patternType.isErroneous() &&
2256                                 types.isUnconditionallyExactTypeBased(seltype, patternType);
2257                         if (unconditional) {
2258                             if (hasUnconditionalPattern) {
2259                                 log.error(pat.pos(), Errors.DuplicateUnconditionalPattern);
2260                             } else if (hasDefault) {
2261                                 log.error(pat.pos(), Errors.UnconditionalPatternAndDefault);
2262                             } else if (booleanSwitch && constants.containsAll(Set.of(0, 1))) {
2263                                 log.error(pat.pos(), Errors.UnconditionalPatternAndBothBooleanValues);
2264                             }
2265                             hasUnconditionalPattern = true;
2266                             unconditionalCaseLabel = label;
2267                         }
2268                         lastPatternErroneous = patternType.isErroneous();
2269                     } else {
2270                         Assert.error();
2271                     }
2272                     currentBindings = matchBindingsComputer.switchCase(label, currentBindings, matchBindings);
2273                 }
2274 
2275                 if (guardBindings != null) {
2276                     currentBindings = matchBindingsComputer.caseGuard(c, currentBindings, guardBindings);
2277                 }
2278 
2279                 Env<AttrContext> caseEnv =
2280                         bindingEnv(switchEnv, c, currentBindings.bindingsWhenTrue);
2281                 try {
2282                     attribCase.accept(c, caseEnv);
2283                 } finally {
2284                     caseEnv.info.scope.leave();
2285                 }
2286                 addVars(c.stats, switchEnv.info.scope);
2287 
2288                 preFlow(c);
2289                 c.completesNormally = flow.aliveAfter(caseEnv, c, make);
2290             }
2291             if (patternSwitch) {
2292                 chk.checkSwitchCaseStructure(cases);
2293                 chk.checkSwitchCaseLabelDominated(unconditionalCaseLabel, cases);
2294             }
2295             if (switchTree.hasTag(SWITCH)) {
2296                 ((JCSwitch) switchTree).hasUnconditionalPattern =
2297                         hasDefault || hasUnconditionalPattern || lastPatternErroneous;
2298                 ((JCSwitch) switchTree).patternSwitch = patternSwitch;
2299             } else if (switchTree.hasTag(SWITCH_EXPRESSION)) {
2300                 ((JCSwitchExpression) switchTree).hasUnconditionalPattern =
2301                         hasDefault || hasUnconditionalPattern || lastPatternErroneous;
2302                 ((JCSwitchExpression) switchTree).patternSwitch = patternSwitch;
2303             } else {
2304                 Assert.error(switchTree.getTag().name());
2305             }
2306         } finally {
2307             switchEnv.info.scope.leave();
2308         }
2309     }
2310     // where
2311         private ResultInfo caseLabelResultInfo(Type seltype) {
2312             return new ResultInfo(KindSelector.VAL_TYP,
2313                                   !seltype.hasTag(ERROR) ? seltype
2314                                                          : Type.noType);
2315         }
2316         /** Add any variables defined in stats to the switch scope. */
2317         private static void addVars(List<JCStatement> stats, WriteableScope switchScope) {
2318             for (;stats.nonEmpty(); stats = stats.tail) {
2319                 JCTree stat = stats.head;
2320                 if (stat.hasTag(VARDEF))
2321                     switchScope.enter(((JCVariableDecl) stat).sym);
2322             }
2323         }
2324     // where
2325     /** Return the selected enumeration constant symbol, or null. */
2326     private Symbol enumConstant(JCTree tree, Type enumType) {
2327         if (tree.hasTag(IDENT)) {
2328             JCIdent ident = (JCIdent)tree;
2329             Name name = ident.name;
2330             for (Symbol sym : enumType.tsym.members().getSymbolsByName(name)) {
2331                 if (sym.kind == VAR) {
2332                     Symbol s = ident.sym = sym;
2333                     ((VarSymbol)s).getConstValue(); // ensure initializer is evaluated
2334                     ident.type = s.type;
2335                     return ((s.flags_field & Flags.ENUM) == 0)
2336                         ? null : s;
2337                 }
2338             }
2339         }
2340         return null;
2341     }
2342 
2343     public void visitSynchronized(JCSynchronized tree) {
2344         boolean identityType = chk.checkIdentityType(tree.pos(), attribExpr(tree.lock, env));
2345         if (identityType && tree.lock.type != null && tree.lock.type.isValueBased()) {
2346             log.warning(tree.pos(), LintWarnings.AttemptToSynchronizeOnInstanceOfValueBasedClass);
2347         }
2348         attribStat(tree.body, env);
2349         result = null;
2350     }
2351 
2352     public void visitTry(JCTry tree) {
2353         // Create a new local environment with a local
2354         Env<AttrContext> localEnv = env.dup(tree, env.info.dup(env.info.scope.dup()));
2355         try {
2356             boolean isTryWithResource = tree.resources.nonEmpty();
2357             // Create a nested environment for attributing the try block if needed
2358             Env<AttrContext> tryEnv = isTryWithResource ?
2359                 env.dup(tree, localEnv.info.dup(localEnv.info.scope.dup())) :
2360                 localEnv;
2361             try {
2362                 // Attribute resource declarations
2363                 for (JCTree resource : tree.resources) {
2364                     CheckContext twrContext = new Check.NestedCheckContext(resultInfo.checkContext) {
2365                         @Override
2366                         public void report(DiagnosticPosition pos, JCDiagnostic details) {
2367                             chk.basicHandler.report(pos, diags.fragment(Fragments.TryNotApplicableToType(details)));
2368                         }
2369                     };
2370                     ResultInfo twrResult =
2371                         new ResultInfo(KindSelector.VAR,
2372                                        syms.autoCloseableType,
2373                                        twrContext);
2374                     if (resource.hasTag(VARDEF)) {
2375                         attribStat(resource, tryEnv);
2376                         twrResult.check(resource, resource.type);
2377 
2378                         //check that resource type cannot throw InterruptedException
2379                         checkAutoCloseable(localEnv, resource, true);
2380 
2381                         VarSymbol var = ((JCVariableDecl) resource).sym;
2382 
2383                         var.flags_field |= Flags.FINAL;
2384                         var.setData(ElementKind.RESOURCE_VARIABLE);
2385                     } else {
2386                         attribTree(resource, tryEnv, twrResult);
2387                     }
2388                 }
2389                 // Attribute body
2390                 attribStat(tree.body, tryEnv);
2391             } finally {
2392                 if (isTryWithResource)
2393                     tryEnv.info.scope.leave();
2394             }
2395 
2396             // Attribute catch clauses
2397             for (List<JCCatch> l = tree.catchers; l.nonEmpty(); l = l.tail) {
2398                 JCCatch c = l.head;
2399                 Env<AttrContext> catchEnv =
2400                     localEnv.dup(c, localEnv.info.dup(localEnv.info.scope.dup()));
2401                 try {
2402                     Type ctype = attribStat(c.param, catchEnv);
2403                     if (TreeInfo.isMultiCatch(c)) {
2404                         //multi-catch parameter is implicitly marked as final
2405                         c.param.sym.flags_field |= FINAL | UNION;
2406                     }
2407                     if (c.param.sym.kind == VAR) {
2408                         c.param.sym.setData(ElementKind.EXCEPTION_PARAMETER);
2409                     }
2410                     chk.checkType(c.param.vartype.pos(),
2411                                   chk.checkClassType(c.param.vartype.pos(), ctype),
2412                                   syms.throwableType);
2413                     attribStat(c.body, catchEnv);
2414                 } finally {
2415                     catchEnv.info.scope.leave();
2416                 }
2417             }
2418 
2419             // Attribute finalizer
2420             if (tree.finalizer != null) attribStat(tree.finalizer, localEnv);
2421             result = null;
2422         }
2423         finally {
2424             localEnv.info.scope.leave();
2425         }
2426     }
2427 
2428     void checkAutoCloseable(Env<AttrContext> env, JCTree tree, boolean useSite) {
2429         DiagnosticPosition pos = tree.pos();
2430         Type resource = tree.type;
2431         if (!resource.isErroneous() &&
2432             types.asSuper(resource, syms.autoCloseableType.tsym) != null &&
2433             !types.isSameType(resource, syms.autoCloseableType)) { // Don't emit warning for AutoCloseable itself
2434             Symbol close = syms.noSymbol;
2435             Log.DiagnosticHandler discardHandler = log.new DiscardDiagnosticHandler();
2436             try {
2437                 close = rs.resolveQualifiedMethod(pos,
2438                         env,
2439                         types.skipTypeVars(resource, false),
2440                         names.close,
2441                         List.nil(),
2442                         List.nil());
2443             }
2444             finally {
2445                 log.popDiagnosticHandler(discardHandler);
2446             }
2447             if (close.kind == MTH &&
2448                     (useSite || close.owner != syms.autoCloseableType.tsym) &&
2449                     ((MethodSymbol)close).binaryOverrides(syms.autoCloseableClose, resource.tsym, types) &&
2450                     chk.isHandled(syms.interruptedExceptionType, types.memberType(resource, close).getThrownTypes())) {
2451                 if (!useSite && close.owner == resource.tsym) {
2452                     log.warning(TreeInfo.diagnosticPositionFor(close, tree),
2453                         LintWarnings.TryResourceCanThrowInterruptedExc(resource));
2454                 } else {
2455                     log.warning(pos, LintWarnings.TryResourceThrowsInterruptedExc(resource));
2456                 }
2457             }
2458         }
2459     }
2460 
2461     public void visitConditional(JCConditional tree) {
2462         Type condtype = attribExpr(tree.cond, env, syms.booleanType);
2463         MatchBindings condBindings = matchBindings;
2464 
2465         tree.polyKind = (pt().hasTag(NONE) && pt() != Type.recoveryType && pt() != Infer.anyPoly ||
2466                 isBooleanOrNumeric(env, tree)) ?
2467                 PolyKind.STANDALONE : PolyKind.POLY;
2468 
2469         if (tree.polyKind == PolyKind.POLY && resultInfo.pt.hasTag(VOID)) {
2470             //this means we are returning a poly conditional from void-compatible lambda expression
2471             resultInfo.checkContext.report(tree, diags.fragment(Fragments.ConditionalTargetCantBeVoid));
2472             result = tree.type = types.createErrorType(resultInfo.pt);
2473             return;
2474         }
2475 
2476         ResultInfo condInfo = tree.polyKind == PolyKind.STANDALONE ?
2477                 unknownExprInfo :
2478                 resultInfo.dup(conditionalContext(resultInfo.checkContext));
2479 
2480 
2481         // x ? y : z
2482         // include x's bindings when true in y
2483         // include x's bindings when false in z
2484 
2485         Type truetype;
2486         Env<AttrContext> trueEnv = bindingEnv(env, condBindings.bindingsWhenTrue);
2487         try {
2488             truetype = attribTree(tree.truepart, trueEnv, condInfo);
2489         } finally {
2490             trueEnv.info.scope.leave();
2491         }
2492 
2493         MatchBindings trueBindings = matchBindings;
2494 
2495         Type falsetype;
2496         Env<AttrContext> falseEnv = bindingEnv(env, condBindings.bindingsWhenFalse);
2497         try {
2498             falsetype = attribTree(tree.falsepart, falseEnv, condInfo);
2499         } finally {
2500             falseEnv.info.scope.leave();
2501         }
2502 
2503         MatchBindings falseBindings = matchBindings;
2504 
2505         Type owntype = (tree.polyKind == PolyKind.STANDALONE) ?
2506                 condType(List.of(tree.truepart.pos(), tree.falsepart.pos()),
2507                          List.of(truetype, falsetype)) : pt();
2508         if (condtype.constValue() != null &&
2509                 truetype.constValue() != null &&
2510                 falsetype.constValue() != null &&
2511                 !owntype.hasTag(NONE)) {
2512             //constant folding
2513             owntype = cfolder.coerce(condtype.isTrue() ? truetype : falsetype, owntype);
2514         }
2515         result = check(tree, owntype, KindSelector.VAL, resultInfo);
2516         matchBindings = matchBindingsComputer.conditional(tree, condBindings, trueBindings, falseBindings);
2517     }
2518     //where
2519         private boolean isBooleanOrNumeric(Env<AttrContext> env, JCExpression tree) {
2520             switch (tree.getTag()) {
2521                 case LITERAL: return ((JCLiteral)tree).typetag.isSubRangeOf(DOUBLE) ||
2522                               ((JCLiteral)tree).typetag == BOOLEAN ||
2523                               ((JCLiteral)tree).typetag == BOT;
2524                 case LAMBDA: case REFERENCE: return false;
2525                 case PARENS: return isBooleanOrNumeric(env, ((JCParens)tree).expr);
2526                 case CONDEXPR:
2527                     JCConditional condTree = (JCConditional)tree;
2528                     return isBooleanOrNumeric(env, condTree.truepart) &&
2529                             isBooleanOrNumeric(env, condTree.falsepart);
2530                 case APPLY:
2531                     JCMethodInvocation speculativeMethodTree =
2532                             (JCMethodInvocation)deferredAttr.attribSpeculative(
2533                                     tree, env, unknownExprInfo,
2534                                     argumentAttr.withLocalCacheContext());
2535                     Symbol msym = TreeInfo.symbol(speculativeMethodTree.meth);
2536                     Type receiverType = speculativeMethodTree.meth.hasTag(IDENT) ?
2537                             env.enclClass.type :
2538                             ((JCFieldAccess)speculativeMethodTree.meth).selected.type;
2539                     Type owntype = types.memberType(receiverType, msym).getReturnType();
2540                     return primitiveOrBoxed(owntype);
2541                 case NEWCLASS:
2542                     JCExpression className =
2543                             removeClassParams.translate(((JCNewClass)tree).clazz);
2544                     JCExpression speculativeNewClassTree =
2545                             (JCExpression)deferredAttr.attribSpeculative(
2546                                     className, env, unknownTypeInfo,
2547                                     argumentAttr.withLocalCacheContext());
2548                     return primitiveOrBoxed(speculativeNewClassTree.type);
2549                 default:
2550                     Type speculativeType = deferredAttr.attribSpeculative(tree, env, unknownExprInfo,
2551                             argumentAttr.withLocalCacheContext()).type;
2552                     return primitiveOrBoxed(speculativeType);
2553             }
2554         }
2555         //where
2556             boolean primitiveOrBoxed(Type t) {
2557                 return (!t.hasTag(TYPEVAR) && !t.isErroneous() && types.unboxedTypeOrType(t).isPrimitive());
2558             }
2559 
2560             TreeTranslator removeClassParams = new TreeTranslator() {
2561                 @Override
2562                 public void visitTypeApply(JCTypeApply tree) {
2563                     result = translate(tree.clazz);
2564                 }
2565             };
2566 
2567         CheckContext conditionalContext(CheckContext checkContext) {
2568             return new Check.NestedCheckContext(checkContext) {
2569                 //this will use enclosing check context to check compatibility of
2570                 //subexpression against target type; if we are in a method check context,
2571                 //depending on whether boxing is allowed, we could have incompatibilities
2572                 @Override
2573                 public void report(DiagnosticPosition pos, JCDiagnostic details) {
2574                     enclosingContext.report(pos, diags.fragment(Fragments.IncompatibleTypeInConditional(details)));
2575                 }
2576             };
2577         }
2578 
2579         /** Compute the type of a conditional expression, after
2580          *  checking that it exists.  See JLS 15.25. Does not take into
2581          *  account the special case where condition and both arms
2582          *  are constants.
2583          *
2584          *  @param pos      The source position to be used for error
2585          *                  diagnostics.
2586          *  @param thentype The type of the expression's then-part.
2587          *  @param elsetype The type of the expression's else-part.
2588          */
2589         Type condType(List<DiagnosticPosition> positions, List<Type> condTypes) {
2590             if (condTypes.isEmpty()) {
2591                 return syms.objectType; //TODO: how to handle?
2592             }
2593             Type first = condTypes.head;
2594             // If same type, that is the result
2595             if (condTypes.tail.stream().allMatch(t -> types.isSameType(first, t)))
2596                 return first.baseType();
2597 
2598             List<Type> unboxedTypes = condTypes.stream()
2599                                                .map(t -> t.isPrimitive() ? t : types.unboxedType(t))
2600                                                .collect(List.collector());
2601 
2602             // Otherwise, if both arms can be converted to a numeric
2603             // type, return the least numeric type that fits both arms
2604             // (i.e. return larger of the two, or return int if one
2605             // arm is short, the other is char).
2606             if (unboxedTypes.stream().allMatch(t -> t.isPrimitive())) {
2607                 // If one arm has an integer subrange type (i.e., byte,
2608                 // short, or char), and the other is an integer constant
2609                 // that fits into the subrange, return the subrange type.
2610                 for (Type type : unboxedTypes) {
2611                     if (!type.getTag().isStrictSubRangeOf(INT)) {
2612                         continue;
2613                     }
2614                     if (unboxedTypes.stream().filter(t -> t != type).allMatch(t -> t.hasTag(INT) && types.isAssignable(t, type)))
2615                         return type.baseType();
2616                 }
2617 
2618                 for (TypeTag tag : primitiveTags) {
2619                     Type candidate = syms.typeOfTag[tag.ordinal()];
2620                     if (unboxedTypes.stream().allMatch(t -> types.isSubtype(t, candidate))) {
2621                         return candidate;
2622                     }
2623                 }
2624             }
2625 
2626             // Those were all the cases that could result in a primitive
2627             condTypes = condTypes.stream()
2628                                  .map(t -> t.isPrimitive() ? types.boxedClass(t).type : t)
2629                                  .collect(List.collector());
2630 
2631             for (Type type : condTypes) {
2632                 if (condTypes.stream().filter(t -> t != type).allMatch(t -> types.isAssignable(t, type)))
2633                     return type.baseType();
2634             }
2635 
2636             Iterator<DiagnosticPosition> posIt = positions.iterator();
2637 
2638             condTypes = condTypes.stream()
2639                                  .map(t -> chk.checkNonVoid(posIt.next(), t))
2640                                  .collect(List.collector());
2641 
2642             // both are known to be reference types.  The result is
2643             // lub(thentype,elsetype). This cannot fail, as it will
2644             // always be possible to infer "Object" if nothing better.
2645             return types.lub(condTypes.stream()
2646                         .map(t -> t.baseType())
2647                         .filter(t -> !t.hasTag(BOT))
2648                         .collect(List.collector()));
2649         }
2650 
2651     static final TypeTag[] primitiveTags = new TypeTag[]{
2652         BYTE,
2653         CHAR,
2654         SHORT,
2655         INT,
2656         LONG,
2657         FLOAT,
2658         DOUBLE,
2659         BOOLEAN,
2660     };
2661 
2662     Env<AttrContext> bindingEnv(Env<AttrContext> env, List<BindingSymbol> bindings) {
2663         return bindingEnv(env, env.tree, bindings);
2664     }
2665 
2666     Env<AttrContext> bindingEnv(Env<AttrContext> env, JCTree newTree, List<BindingSymbol> bindings) {
2667         Env<AttrContext> env1 = env.dup(newTree, env.info.dup(env.info.scope.dup()));
2668         bindings.forEach(env1.info.scope::enter);
2669         return env1;
2670     }
2671 
2672     public void visitIf(JCIf tree) {
2673         attribExpr(tree.cond, env, syms.booleanType);
2674 
2675         // if (x) { y } [ else z ]
2676         // include x's bindings when true in y
2677         // include x's bindings when false in z
2678 
2679         MatchBindings condBindings = matchBindings;
2680         Env<AttrContext> thenEnv = bindingEnv(env, condBindings.bindingsWhenTrue);
2681 
2682         try {
2683             attribStat(tree.thenpart, thenEnv);
2684         } finally {
2685             thenEnv.info.scope.leave();
2686         }
2687 
2688         preFlow(tree.thenpart);
2689         boolean aliveAfterThen = flow.aliveAfter(env, tree.thenpart, make);
2690         boolean aliveAfterElse;
2691 
2692         if (tree.elsepart != null) {
2693             Env<AttrContext> elseEnv = bindingEnv(env, condBindings.bindingsWhenFalse);
2694             try {
2695                 attribStat(tree.elsepart, elseEnv);
2696             } finally {
2697                 elseEnv.info.scope.leave();
2698             }
2699             preFlow(tree.elsepart);
2700             aliveAfterElse = flow.aliveAfter(env, tree.elsepart, make);
2701         } else {
2702             aliveAfterElse = true;
2703         }
2704 
2705         chk.checkEmptyIf(tree);
2706 
2707         List<BindingSymbol> afterIfBindings = List.nil();
2708 
2709         if (aliveAfterThen && !aliveAfterElse) {
2710             afterIfBindings = condBindings.bindingsWhenTrue;
2711         } else if (aliveAfterElse && !aliveAfterThen) {
2712             afterIfBindings = condBindings.bindingsWhenFalse;
2713         }
2714 
2715         addBindings2Scope(tree, afterIfBindings);
2716 
2717         result = null;
2718     }
2719 
2720         void preFlow(JCTree tree) {
2721             attrRecover.doRecovery();
2722             new PostAttrAnalyzer() {
2723                 @Override
2724                 public void scan(JCTree tree) {
2725                     if (tree == null ||
2726                             (tree.type != null &&
2727                             tree.type == Type.stuckType)) {
2728                         //don't touch stuck expressions!
2729                         return;
2730                     }
2731                     super.scan(tree);
2732                 }
2733 
2734                 @Override
2735                 public void visitClassDef(JCClassDecl that) {
2736                     if (that.sym != null) {
2737                         // Method preFlow shouldn't visit class definitions
2738                         // that have not been entered and attributed.
2739                         // See JDK-8254557 and JDK-8203277 for more details.
2740                         super.visitClassDef(that);
2741                     }
2742                 }
2743 
2744                 @Override
2745                 public void visitLambda(JCLambda that) {
2746                     if (that.type != null) {
2747                         // Method preFlow shouldn't visit lambda expressions
2748                         // that have not been entered and attributed.
2749                         // See JDK-8254557 and JDK-8203277 for more details.
2750                         super.visitLambda(that);
2751                     }
2752                 }
2753             }.scan(tree);
2754         }
2755 
2756     public void visitExec(JCExpressionStatement tree) {
2757         //a fresh environment is required for 292 inference to work properly ---
2758         //see Infer.instantiatePolymorphicSignatureInstance()
2759         Env<AttrContext> localEnv = env.dup(tree);
2760         attribExpr(tree.expr, localEnv);
2761         result = null;
2762     }
2763 
2764     public void visitBreak(JCBreak tree) {
2765         tree.target = findJumpTarget(tree.pos(), tree.getTag(), tree.label, env);
2766         result = null;
2767     }
2768 
2769     public void visitYield(JCYield tree) {
2770         if (env.info.yieldResult != null) {
2771             attribTree(tree.value, env, env.info.yieldResult);
2772             tree.target = findJumpTarget(tree.pos(), tree.getTag(), names.empty, env);
2773         } else {
2774             log.error(tree.pos(), tree.value.hasTag(PARENS)
2775                     ? Errors.NoSwitchExpressionQualify
2776                     : Errors.NoSwitchExpression);
2777             attribTree(tree.value, env, unknownExprInfo);
2778         }
2779         result = null;
2780     }
2781 
2782     public void visitContinue(JCContinue tree) {
2783         tree.target = findJumpTarget(tree.pos(), tree.getTag(), tree.label, env);
2784         result = null;
2785     }
2786     //where
2787         /** Return the target of a break, continue or yield statement,
2788          *  if it exists, report an error if not.
2789          *  Note: The target of a labelled break or continue is the
2790          *  (non-labelled) statement tree referred to by the label,
2791          *  not the tree representing the labelled statement itself.
2792          *
2793          *  @param pos     The position to be used for error diagnostics
2794          *  @param tag     The tag of the jump statement. This is either
2795          *                 Tree.BREAK or Tree.CONTINUE.
2796          *  @param label   The label of the jump statement, or null if no
2797          *                 label is given.
2798          *  @param env     The environment current at the jump statement.
2799          */
2800         private JCTree findJumpTarget(DiagnosticPosition pos,
2801                                                    JCTree.Tag tag,
2802                                                    Name label,
2803                                                    Env<AttrContext> env) {
2804             Pair<JCTree, Error> jumpTarget = findJumpTargetNoError(tag, label, env);
2805 
2806             if (jumpTarget.snd != null) {
2807                 log.error(pos, jumpTarget.snd);
2808             }
2809 
2810             return jumpTarget.fst;
2811         }
2812         /** Return the target of a break or continue statement, if it exists,
2813          *  report an error if not.
2814          *  Note: The target of a labelled break or continue is the
2815          *  (non-labelled) statement tree referred to by the label,
2816          *  not the tree representing the labelled statement itself.
2817          *
2818          *  @param tag     The tag of the jump statement. This is either
2819          *                 Tree.BREAK or Tree.CONTINUE.
2820          *  @param label   The label of the jump statement, or null if no
2821          *                 label is given.
2822          *  @param env     The environment current at the jump statement.
2823          */
2824         private Pair<JCTree, JCDiagnostic.Error> findJumpTargetNoError(JCTree.Tag tag,
2825                                                                        Name label,
2826                                                                        Env<AttrContext> env) {
2827             // Search environments outwards from the point of jump.
2828             Env<AttrContext> env1 = env;
2829             JCDiagnostic.Error pendingError = null;
2830             LOOP:
2831             while (env1 != null) {
2832                 switch (env1.tree.getTag()) {
2833                     case LABELLED:
2834                         JCLabeledStatement labelled = (JCLabeledStatement)env1.tree;
2835                         if (label == labelled.label) {
2836                             // If jump is a continue, check that target is a loop.
2837                             if (tag == CONTINUE) {
2838                                 if (!labelled.body.hasTag(DOLOOP) &&
2839                                         !labelled.body.hasTag(WHILELOOP) &&
2840                                         !labelled.body.hasTag(FORLOOP) &&
2841                                         !labelled.body.hasTag(FOREACHLOOP)) {
2842                                     pendingError = Errors.NotLoopLabel(label);
2843                                 }
2844                                 // Found labelled statement target, now go inwards
2845                                 // to next non-labelled tree.
2846                                 return Pair.of(TreeInfo.referencedStatement(labelled), pendingError);
2847                             } else {
2848                                 return Pair.of(labelled, pendingError);
2849                             }
2850                         }
2851                         break;
2852                     case DOLOOP:
2853                     case WHILELOOP:
2854                     case FORLOOP:
2855                     case FOREACHLOOP:
2856                         if (label == null) return Pair.of(env1.tree, pendingError);
2857                         break;
2858                     case SWITCH:
2859                         if (label == null && tag == BREAK) return Pair.of(env1.tree, null);
2860                         break;
2861                     case SWITCH_EXPRESSION:
2862                         if (tag == YIELD) {
2863                             return Pair.of(env1.tree, null);
2864                         } else if (tag == BREAK) {
2865                             pendingError = Errors.BreakOutsideSwitchExpression;
2866                         } else {
2867                             pendingError = Errors.ContinueOutsideSwitchExpression;
2868                         }
2869                         break;
2870                     case LAMBDA:
2871                     case METHODDEF:
2872                     case CLASSDEF:
2873                         break LOOP;
2874                     default:
2875                 }
2876                 env1 = env1.next;
2877             }
2878             if (label != null)
2879                 return Pair.of(null, Errors.UndefLabel(label));
2880             else if (pendingError != null)
2881                 return Pair.of(null, pendingError);
2882             else if (tag == CONTINUE)
2883                 return Pair.of(null, Errors.ContOutsideLoop);
2884             else
2885                 return Pair.of(null, Errors.BreakOutsideSwitchLoop);
2886         }
2887 
2888     public void visitReturn(JCReturn tree) {
2889         // Check that there is an enclosing method which is
2890         // nested within than the enclosing class.
2891         if (env.info.returnResult == null) {
2892             log.error(tree.pos(), Errors.RetOutsideMeth);
2893         } else if (env.info.yieldResult != null) {
2894             log.error(tree.pos(), Errors.ReturnOutsideSwitchExpression);
2895             if (tree.expr != null) {
2896                 attribExpr(tree.expr, env, env.info.yieldResult.pt);
2897             }
2898         } else if (!env.info.isLambda &&
2899                 env.enclMethod != null &&
2900                 TreeInfo.isCompactConstructor(env.enclMethod)) {
2901             log.error(env.enclMethod,
2902                     Errors.InvalidCanonicalConstructorInRecord(Fragments.Compact, env.enclMethod.sym.name, Fragments.CanonicalCantHaveReturnStatement));
2903         } else {
2904             // Attribute return expression, if it exists, and check that
2905             // it conforms to result type of enclosing method.
2906             if (tree.expr != null) {
2907                 if (env.info.returnResult.pt.hasTag(VOID)) {
2908                     env.info.returnResult.checkContext.report(tree.expr.pos(),
2909                               diags.fragment(Fragments.UnexpectedRetVal));
2910                 }
2911                 attribTree(tree.expr, env, env.info.returnResult);
2912             } else if (!env.info.returnResult.pt.hasTag(VOID) &&
2913                     !env.info.returnResult.pt.hasTag(NONE)) {
2914                 env.info.returnResult.checkContext.report(tree.pos(),
2915                               diags.fragment(Fragments.MissingRetVal(env.info.returnResult.pt)));
2916             }
2917         }
2918         result = null;
2919     }
2920 
2921     public void visitThrow(JCThrow tree) {
2922         Type owntype = attribExpr(tree.expr, env, Type.noType);
2923         chk.checkType(tree, owntype, syms.throwableType);
2924         result = null;
2925     }
2926 
2927     public void visitAssert(JCAssert tree) {
2928         attribExpr(tree.cond, env, syms.booleanType);
2929         if (tree.detail != null) {
2930             chk.checkNonVoid(tree.detail.pos(), attribExpr(tree.detail, env));
2931         }
2932         result = null;
2933     }
2934 
2935      /** Visitor method for method invocations.
2936      *  NOTE: The method part of an application will have in its type field
2937      *        the return type of the method, not the method's type itself!
2938      */
2939     public void visitApply(JCMethodInvocation tree) {
2940         // The local environment of a method application is
2941         // a new environment nested in the current one.
2942         Env<AttrContext> localEnv = env.dup(tree, env.info.dup());
2943 
2944         // The types of the actual method arguments.
2945         List<Type> argtypes;
2946 
2947         // The types of the actual method type arguments.
2948         List<Type> typeargtypes = null;
2949 
2950         Name methName = TreeInfo.name(tree.meth);
2951 
2952         boolean isConstructorCall =
2953             methName == names._this || methName == names._super;
2954 
2955         ListBuffer<Type> argtypesBuf = new ListBuffer<>();
2956         if (isConstructorCall) {
2957 
2958             // Attribute arguments, yielding list of argument types.
2959             KindSelector kind = attribArgs(KindSelector.MTH, tree.args, localEnv, argtypesBuf);
2960             argtypes = argtypesBuf.toList();
2961             typeargtypes = attribTypes(tree.typeargs, localEnv);
2962 
2963             // Done with this()/super() parameters. End of constructor prologue.
2964             env.info.ctorPrologue = false;
2965 
2966             // Variable `site' points to the class in which the called
2967             // constructor is defined.
2968             Type site = env.enclClass.sym.type;
2969             if (methName == names._super) {
2970                 if (site == syms.objectType) {
2971                     log.error(tree.meth.pos(), Errors.NoSuperclass(site));
2972                     site = types.createErrorType(syms.objectType);
2973                 } else {
2974                     site = types.supertype(site);
2975                 }
2976             }
2977 
2978             if (site.hasTag(CLASS)) {
2979                 Type encl = site.getEnclosingType();
2980                 while (encl != null && encl.hasTag(TYPEVAR))
2981                     encl = encl.getUpperBound();
2982                 if (encl.hasTag(CLASS)) {
2983                     // we are calling a nested class
2984 
2985                     if (tree.meth.hasTag(SELECT)) {
2986                         JCTree qualifier = ((JCFieldAccess) tree.meth).selected;
2987 
2988                         // We are seeing a prefixed call, of the form
2989                         //     <expr>.super(...).
2990                         // Check that the prefix expression conforms
2991                         // to the outer instance type of the class.
2992                         chk.checkRefType(qualifier.pos(),
2993                                          attribExpr(qualifier, localEnv,
2994                                                     encl));
2995                     }
2996                 } else if (tree.meth.hasTag(SELECT)) {
2997                     log.error(tree.meth.pos(),
2998                               Errors.IllegalQualNotIcls(site.tsym));
2999                     attribExpr(((JCFieldAccess) tree.meth).selected, localEnv, site);
3000                 }
3001 
3002                 if (tree.meth.hasTag(IDENT)) {
3003                     // non-qualified super(...) call; check whether explicit constructor
3004                     // invocation is well-formed. If the super class is an inner class,
3005                     // make sure that an appropriate implicit qualifier exists. If the super
3006                     // class is a local class, make sure that the current class is defined
3007                     // in the same context as the local class.
3008                     checkNewInnerClass(tree.meth.pos(), localEnv, site, true);
3009                 }
3010 
3011                 // if we're calling a java.lang.Enum constructor,
3012                 // prefix the implicit String and int parameters
3013                 if (site.tsym == syms.enumSym)
3014                     argtypes = argtypes.prepend(syms.intType).prepend(syms.stringType);
3015 
3016                 // Resolve the called constructor under the assumption
3017                 // that we are referring to a superclass instance of the
3018                 // current instance (JLS ???).
3019                 boolean selectSuperPrev = localEnv.info.selectSuper;
3020                 localEnv.info.selectSuper = true;
3021                 localEnv.info.pendingResolutionPhase = null;
3022                 Symbol sym = rs.resolveConstructor(
3023                     tree.meth.pos(), localEnv, site, argtypes, typeargtypes);
3024                 localEnv.info.selectSuper = selectSuperPrev;
3025 
3026                 // Set method symbol to resolved constructor...
3027                 TreeInfo.setSymbol(tree.meth, sym);
3028 
3029                 // ...and check that it is legal in the current context.
3030                 // (this will also set the tree's type)
3031                 Type mpt = newMethodTemplate(resultInfo.pt, argtypes, typeargtypes);
3032                 checkId(tree.meth, site, sym, localEnv,
3033                         new ResultInfo(kind, mpt));
3034             } else if (site.hasTag(ERROR) && tree.meth.hasTag(SELECT)) {
3035                 attribExpr(((JCFieldAccess) tree.meth).selected, localEnv, site);
3036             }
3037             // Otherwise, `site' is an error type and we do nothing
3038             result = tree.type = syms.voidType;
3039         } else {
3040             // Otherwise, we are seeing a regular method call.
3041             // Attribute the arguments, yielding list of argument types, ...
3042             KindSelector kind = attribArgs(KindSelector.VAL, tree.args, localEnv, argtypesBuf);
3043             argtypes = argtypesBuf.toList();
3044             typeargtypes = attribAnyTypes(tree.typeargs, localEnv);
3045 
3046             // ... and attribute the method using as a prototype a methodtype
3047             // whose formal argument types is exactly the list of actual
3048             // arguments (this will also set the method symbol).
3049             Type mpt = newMethodTemplate(resultInfo.pt, argtypes, typeargtypes);
3050             localEnv.info.pendingResolutionPhase = null;
3051             Type mtype = attribTree(tree.meth, localEnv, new ResultInfo(kind, mpt, resultInfo.checkContext));
3052 
3053             // Compute the result type.
3054             Type restype = mtype.getReturnType();
3055             if (restype.hasTag(WILDCARD))
3056                 throw new AssertionError(mtype);
3057 
3058             Type qualifier = (tree.meth.hasTag(SELECT))
3059                     ? ((JCFieldAccess) tree.meth).selected.type
3060                     : env.enclClass.sym.type;
3061             Symbol msym = TreeInfo.symbol(tree.meth);
3062             restype = adjustMethodReturnType(msym, qualifier, methName, argtypes, restype);
3063 
3064             chk.checkRefTypes(tree.typeargs, typeargtypes);
3065 
3066             // Check that value of resulting type is admissible in the
3067             // current context.  Also, capture the return type
3068             Type capturedRes = resultInfo.checkContext.inferenceContext().cachedCapture(tree, restype, true);
3069             result = check(tree, capturedRes, KindSelector.VAL, resultInfo);
3070         }
3071         chk.checkRequiresIdentity(tree, env.info.lint);
3072         chk.validate(tree.typeargs, localEnv);
3073     }
3074     //where
3075         Type adjustMethodReturnType(Symbol msym, Type qualifierType, Name methodName, List<Type> argtypes, Type restype) {
3076             if (msym != null &&
3077                     (msym.owner == syms.objectType.tsym || msym.owner.isInterface()) &&
3078                     methodName == names.getClass &&
3079                     argtypes.isEmpty()) {
3080                 // as a special case, x.getClass() has type Class<? extends |X|>
3081                 return new ClassType(restype.getEnclosingType(),
3082                         List.of(new WildcardType(types.erasure(qualifierType.baseType()),
3083                                 BoundKind.EXTENDS,
3084                                 syms.boundClass)),
3085                         restype.tsym,
3086                         restype.getMetadata());
3087             } else if (msym != null &&
3088                     msym.owner == syms.arrayClass &&
3089                     methodName == names.clone &&
3090                     types.isArray(qualifierType)) {
3091                 // as a special case, array.clone() has a result that is
3092                 // the same as static type of the array being cloned
3093                 return qualifierType;
3094             } else {
3095                 return restype;
3096             }
3097         }
3098 
3099         /** Obtain a method type with given argument types.
3100          */
3101         Type newMethodTemplate(Type restype, List<Type> argtypes, List<Type> typeargtypes) {
3102             MethodType mt = new MethodType(argtypes, restype, List.nil(), syms.methodClass);
3103             return (typeargtypes == null) ? mt : (Type)new ForAll(typeargtypes, mt);
3104         }
3105 
3106     public void visitNewClass(final JCNewClass tree) {
3107         Type owntype = types.createErrorType(tree.type);
3108 
3109         // The local environment of a class creation is
3110         // a new environment nested in the current one.
3111         Env<AttrContext> localEnv = env.dup(tree, env.info.dup());
3112 
3113         // The anonymous inner class definition of the new expression,
3114         // if one is defined by it.
3115         JCClassDecl cdef = tree.def;
3116 
3117         // If enclosing class is given, attribute it, and
3118         // complete class name to be fully qualified
3119         JCExpression clazz = tree.clazz; // Class field following new
3120         JCExpression clazzid;            // Identifier in class field
3121         JCAnnotatedType annoclazzid;     // Annotated type enclosing clazzid
3122         annoclazzid = null;
3123 
3124         if (clazz.hasTag(TYPEAPPLY)) {
3125             clazzid = ((JCTypeApply) clazz).clazz;
3126             if (clazzid.hasTag(ANNOTATED_TYPE)) {
3127                 annoclazzid = (JCAnnotatedType) clazzid;
3128                 clazzid = annoclazzid.underlyingType;
3129             }
3130         } else {
3131             if (clazz.hasTag(ANNOTATED_TYPE)) {
3132                 annoclazzid = (JCAnnotatedType) clazz;
3133                 clazzid = annoclazzid.underlyingType;
3134             } else {
3135                 clazzid = clazz;
3136             }
3137         }
3138 
3139         JCExpression clazzid1 = clazzid; // The same in fully qualified form
3140 
3141         if (tree.encl != null) {
3142             // We are seeing a qualified new, of the form
3143             //    <expr>.new C <...> (...) ...
3144             // In this case, we let clazz stand for the name of the
3145             // allocated class C prefixed with the type of the qualifier
3146             // expression, so that we can
3147             // resolve it with standard techniques later. I.e., if
3148             // <expr> has type T, then <expr>.new C <...> (...)
3149             // yields a clazz T.C.
3150             Type encltype = chk.checkRefType(tree.encl.pos(),
3151                                              attribExpr(tree.encl, env));
3152             // TODO 308: in <expr>.new C, do we also want to add the type annotations
3153             // from expr to the combined type, or not? Yes, do this.
3154             clazzid1 = make.at(clazz.pos).Select(make.Type(encltype),
3155                                                  ((JCIdent) clazzid).name);
3156 
3157             EndPosTable endPosTable = this.env.toplevel.endPositions;
3158             endPosTable.storeEnd(clazzid1, clazzid.getEndPosition(endPosTable));
3159             if (clazz.hasTag(ANNOTATED_TYPE)) {
3160                 JCAnnotatedType annoType = (JCAnnotatedType) clazz;
3161                 List<JCAnnotation> annos = annoType.annotations;
3162 
3163                 if (annoType.underlyingType.hasTag(TYPEAPPLY)) {
3164                     clazzid1 = make.at(tree.pos).
3165                         TypeApply(clazzid1,
3166                                   ((JCTypeApply) clazz).arguments);
3167                 }
3168 
3169                 clazzid1 = make.at(tree.pos).
3170                     AnnotatedType(annos, clazzid1);
3171             } else if (clazz.hasTag(TYPEAPPLY)) {
3172                 clazzid1 = make.at(tree.pos).
3173                     TypeApply(clazzid1,
3174                               ((JCTypeApply) clazz).arguments);
3175             }
3176 
3177             clazz = clazzid1;
3178         }
3179 
3180         // Attribute clazz expression and store
3181         // symbol + type back into the attributed tree.
3182         Type clazztype = TreeInfo.isEnumInit(env.tree) ?
3183             attribIdentAsEnumType(env, (JCIdent)clazz) :
3184             attribType(clazz, env);
3185 
3186         clazztype = chk.checkDiamond(tree, clazztype);
3187         chk.validate(clazz, localEnv);
3188         if (tree.encl != null) {
3189             // We have to work in this case to store
3190             // symbol + type back into the attributed tree.
3191             tree.clazz.type = clazztype;
3192             TreeInfo.setSymbol(clazzid, TreeInfo.symbol(clazzid1));
3193             clazzid.type = ((JCIdent) clazzid).sym.type;
3194             if (annoclazzid != null) {
3195                 annoclazzid.type = clazzid.type;
3196             }
3197             if (!clazztype.isErroneous()) {
3198                 if (cdef != null && clazztype.tsym.isInterface()) {
3199                     log.error(tree.encl.pos(), Errors.AnonClassImplIntfNoQualForNew);
3200                 } else if (clazztype.tsym.isStatic()) {
3201                     log.error(tree.encl.pos(), Errors.QualifiedNewOfStaticClass(clazztype.tsym));
3202                 }
3203             }
3204         } else {
3205             // Check for the existence of an apropos outer instance
3206             checkNewInnerClass(tree.pos(), env, clazztype, false);
3207         }
3208 
3209         // Attribute constructor arguments.
3210         ListBuffer<Type> argtypesBuf = new ListBuffer<>();
3211         final KindSelector pkind =
3212             attribArgs(KindSelector.VAL, tree.args, localEnv, argtypesBuf);
3213         List<Type> argtypes = argtypesBuf.toList();
3214         List<Type> typeargtypes = attribTypes(tree.typeargs, localEnv);
3215 
3216         if (clazztype.hasTag(CLASS) || clazztype.hasTag(ERROR)) {
3217             // Enums may not be instantiated except implicitly
3218             if ((clazztype.tsym.flags_field & Flags.ENUM) != 0 &&
3219                 (!env.tree.hasTag(VARDEF) ||
3220                  (((JCVariableDecl) env.tree).mods.flags & Flags.ENUM) == 0 ||
3221                  ((JCVariableDecl) env.tree).init != tree))
3222                 log.error(tree.pos(), Errors.EnumCantBeInstantiated);
3223 
3224             boolean isSpeculativeDiamondInferenceRound = TreeInfo.isDiamond(tree) &&
3225                     resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.SPECULATIVE;
3226             boolean skipNonDiamondPath = false;
3227             // Check that class is not abstract
3228             if (cdef == null && !tree.classDeclRemoved() && !isSpeculativeDiamondInferenceRound && // class body may be nulled out in speculative tree copy
3229                 (clazztype.tsym.flags() & (ABSTRACT | INTERFACE)) != 0) {
3230                 log.error(tree.pos(),
3231                           Errors.AbstractCantBeInstantiated(clazztype.tsym));
3232                 skipNonDiamondPath = true;
3233             } else if (cdef != null && clazztype.tsym.isInterface()) {
3234                 // Check that no constructor arguments are given to
3235                 // anonymous classes implementing an interface
3236                 if (!argtypes.isEmpty())
3237                     log.error(tree.args.head.pos(), Errors.AnonClassImplIntfNoArgs);
3238 
3239                 if (!typeargtypes.isEmpty())
3240                     log.error(tree.typeargs.head.pos(), Errors.AnonClassImplIntfNoTypeargs);
3241 
3242                 // Error recovery: pretend no arguments were supplied.
3243                 argtypes = List.nil();
3244                 typeargtypes = List.nil();
3245                 skipNonDiamondPath = true;
3246             }
3247             if (TreeInfo.isDiamond(tree)) {
3248                 ClassType site = new ClassType(clazztype.getEnclosingType(),
3249                             clazztype.tsym.type.getTypeArguments(),
3250                                                clazztype.tsym,
3251                                                clazztype.getMetadata());
3252 
3253                 Env<AttrContext> diamondEnv = localEnv.dup(tree);
3254                 diamondEnv.info.selectSuper = cdef != null || tree.classDeclRemoved();
3255                 diamondEnv.info.pendingResolutionPhase = null;
3256 
3257                 //if the type of the instance creation expression is a class type
3258                 //apply method resolution inference (JLS 15.12.2.7). The return type
3259                 //of the resolved constructor will be a partially instantiated type
3260                 Symbol constructor = rs.resolveDiamond(tree.pos(),
3261                             diamondEnv,
3262                             site,
3263                             argtypes,
3264                             typeargtypes);
3265                 tree.constructor = constructor.baseSymbol();
3266 
3267                 final TypeSymbol csym = clazztype.tsym;
3268                 ResultInfo diamondResult = new ResultInfo(pkind, newMethodTemplate(resultInfo.pt, argtypes, typeargtypes),
3269                         diamondContext(tree, csym, resultInfo.checkContext), CheckMode.NO_TREE_UPDATE);
3270                 Type constructorType = tree.constructorType = types.createErrorType(clazztype);
3271                 constructorType = checkId(tree, site,
3272                         constructor,
3273                         diamondEnv,
3274                         diamondResult);
3275 
3276                 tree.clazz.type = types.createErrorType(clazztype);
3277                 if (!constructorType.isErroneous()) {
3278                     tree.clazz.type = clazz.type = constructorType.getReturnType();
3279                     tree.constructorType = types.createMethodTypeWithReturn(constructorType, syms.voidType);
3280                 }
3281                 clazztype = chk.checkClassType(tree.clazz, tree.clazz.type, true);
3282             }
3283 
3284             // Resolve the called constructor under the assumption
3285             // that we are referring to a superclass instance of the
3286             // current instance (JLS ???).
3287             else if (!skipNonDiamondPath) {
3288                 //the following code alters some of the fields in the current
3289                 //AttrContext - hence, the current context must be dup'ed in
3290                 //order to avoid downstream failures
3291                 Env<AttrContext> rsEnv = localEnv.dup(tree);
3292                 rsEnv.info.selectSuper = cdef != null;
3293                 rsEnv.info.pendingResolutionPhase = null;
3294                 tree.constructor = rs.resolveConstructor(
3295                     tree.pos(), rsEnv, clazztype, argtypes, typeargtypes);
3296                 if (cdef == null) { //do not check twice!
3297                     tree.constructorType = checkId(tree,
3298                             clazztype,
3299                             tree.constructor,
3300                             rsEnv,
3301                             new ResultInfo(pkind, newMethodTemplate(syms.voidType, argtypes, typeargtypes), CheckMode.NO_TREE_UPDATE));
3302                     if (rsEnv.info.lastResolveVarargs())
3303                         Assert.check(tree.constructorType.isErroneous() || tree.varargsElement != null);
3304                 }
3305             }
3306 
3307             chk.checkRequiresIdentity(tree, env.info.lint);
3308 
3309             if (cdef != null) {
3310                 visitAnonymousClassDefinition(tree, clazz, clazztype, cdef, localEnv, argtypes, typeargtypes, pkind);
3311                 return;
3312             }
3313 
3314             if (tree.constructor != null && tree.constructor.kind == MTH)
3315                 owntype = clazztype;
3316         }
3317         result = check(tree, owntype, KindSelector.VAL, resultInfo);
3318         InferenceContext inferenceContext = resultInfo.checkContext.inferenceContext();
3319         if (tree.constructorType != null && inferenceContext.free(tree.constructorType)) {
3320             //we need to wait for inference to finish and then replace inference vars in the constructor type
3321             inferenceContext.addFreeTypeListener(List.of(tree.constructorType),
3322                     instantiatedContext -> {
3323                         tree.constructorType = instantiatedContext.asInstType(tree.constructorType);
3324                     });
3325         }
3326         chk.validate(tree.typeargs, localEnv);
3327     }
3328 
3329         // where
3330         private void visitAnonymousClassDefinition(JCNewClass tree, JCExpression clazz, Type clazztype,
3331                                                    JCClassDecl cdef, Env<AttrContext> localEnv,
3332                                                    List<Type> argtypes, List<Type> typeargtypes,
3333                                                    KindSelector pkind) {
3334             // We are seeing an anonymous class instance creation.
3335             // In this case, the class instance creation
3336             // expression
3337             //
3338             //    E.new <typeargs1>C<typargs2>(args) { ... }
3339             //
3340             // is represented internally as
3341             //
3342             //    E . new <typeargs1>C<typargs2>(args) ( class <empty-name> { ... } )  .
3343             //
3344             // This expression is then *transformed* as follows:
3345             //
3346             // (1) add an extends or implements clause
3347             // (2) add a constructor.
3348             //
3349             // For instance, if C is a class, and ET is the type of E,
3350             // the expression
3351             //
3352             //    E.new <typeargs1>C<typargs2>(args) { ... }
3353             //
3354             // is translated to (where X is a fresh name and typarams is the
3355             // parameter list of the super constructor):
3356             //
3357             //   new <typeargs1>X(<*nullchk*>E, args) where
3358             //     X extends C<typargs2> {
3359             //       <typarams> X(ET e, args) {
3360             //         e.<typeargs1>super(args)
3361             //       }
3362             //       ...
3363             //     }
3364             InferenceContext inferenceContext = resultInfo.checkContext.inferenceContext();
3365             Type enclType = clazztype.getEnclosingType();
3366             if (enclType != null &&
3367                     enclType.hasTag(CLASS) &&
3368                     !chk.checkDenotable((ClassType)enclType)) {
3369                 log.error(tree.encl, Errors.EnclosingClassTypeNonDenotable(enclType));
3370             }
3371             final boolean isDiamond = TreeInfo.isDiamond(tree);
3372             if (isDiamond
3373                     && ((tree.constructorType != null && inferenceContext.free(tree.constructorType))
3374                     || (tree.clazz.type != null && inferenceContext.free(tree.clazz.type)))) {
3375                 final ResultInfo resultInfoForClassDefinition = this.resultInfo;
3376                 Env<AttrContext> dupLocalEnv = copyEnv(localEnv);
3377                 inferenceContext.addFreeTypeListener(List.of(tree.constructorType, tree.clazz.type),
3378                         instantiatedContext -> {
3379                             tree.constructorType = instantiatedContext.asInstType(tree.constructorType);
3380                             tree.clazz.type = clazz.type = instantiatedContext.asInstType(clazz.type);
3381                             ResultInfo prevResult = this.resultInfo;
3382                             try {
3383                                 this.resultInfo = resultInfoForClassDefinition;
3384                                 visitAnonymousClassDefinition(tree, clazz, clazz.type, cdef,
3385                                         dupLocalEnv, argtypes, typeargtypes, pkind);
3386                             } finally {
3387                                 this.resultInfo = prevResult;
3388                             }
3389                         });
3390             } else {
3391                 if (isDiamond && clazztype.hasTag(CLASS)) {
3392                     List<Type> invalidDiamondArgs = chk.checkDiamondDenotable((ClassType)clazztype);
3393                     if (!clazztype.isErroneous() && invalidDiamondArgs.nonEmpty()) {
3394                         // One or more types inferred in the previous steps is non-denotable.
3395                         Fragment fragment = Diamond(clazztype.tsym);
3396                         log.error(tree.clazz.pos(),
3397                                 Errors.CantApplyDiamond1(
3398                                         fragment,
3399                                         invalidDiamondArgs.size() > 1 ?
3400                                                 DiamondInvalidArgs(invalidDiamondArgs, fragment) :
3401                                                 DiamondInvalidArg(invalidDiamondArgs, fragment)));
3402                     }
3403                     // For <>(){}, inferred types must also be accessible.
3404                     for (Type t : clazztype.getTypeArguments()) {
3405                         rs.checkAccessibleType(env, t);
3406                     }
3407                 }
3408 
3409                 // If we already errored, be careful to avoid a further avalanche. ErrorType answers
3410                 // false for isInterface call even when the original type is an interface.
3411                 boolean implementing = clazztype.tsym.isInterface() ||
3412                         clazztype.isErroneous() && !clazztype.getOriginalType().hasTag(NONE) &&
3413                         clazztype.getOriginalType().tsym.isInterface();
3414 
3415                 if (implementing) {
3416                     cdef.implementing = List.of(clazz);
3417                 } else {
3418                     cdef.extending = clazz;
3419                 }
3420 
3421                 if (resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.CHECK &&
3422                     rs.isSerializable(clazztype)) {
3423                     localEnv.info.isSerializable = true;
3424                 }
3425 
3426                 attribStat(cdef, localEnv);
3427 
3428                 List<Type> finalargtypes;
3429                 // If an outer instance is given,
3430                 // prefix it to the constructor arguments
3431                 // and delete it from the new expression
3432                 if (tree.encl != null && !clazztype.tsym.isInterface()) {
3433                     finalargtypes = argtypes.prepend(tree.encl.type);
3434                 } else {
3435                     finalargtypes = argtypes;
3436                 }
3437 
3438                 // Reassign clazztype and recompute constructor. As this necessarily involves
3439                 // another attribution pass for deferred types in the case of <>, replicate
3440                 // them. Original arguments have right decorations already.
3441                 if (isDiamond && pkind.contains(KindSelector.POLY)) {
3442                     finalargtypes = finalargtypes.map(deferredAttr.deferredCopier);
3443                 }
3444 
3445                 clazztype = clazztype.hasTag(ERROR) ? types.createErrorType(cdef.sym.type)
3446                                                     : cdef.sym.type;
3447                 Symbol sym = tree.constructor = rs.resolveConstructor(
3448                         tree.pos(), localEnv, clazztype, finalargtypes, typeargtypes);
3449                 Assert.check(!sym.kind.isResolutionError());
3450                 tree.constructor = sym;
3451                 tree.constructorType = checkId(tree,
3452                         clazztype,
3453                         tree.constructor,
3454                         localEnv,
3455                         new ResultInfo(pkind, newMethodTemplate(syms.voidType, finalargtypes, typeargtypes), CheckMode.NO_TREE_UPDATE));
3456             }
3457             Type owntype = (tree.constructor != null && tree.constructor.kind == MTH) ?
3458                                 clazztype : types.createErrorType(tree.type);
3459             result = check(tree, owntype, KindSelector.VAL, resultInfo.dup(CheckMode.NO_INFERENCE_HOOK));
3460             chk.validate(tree.typeargs, localEnv);
3461         }
3462 
3463         CheckContext diamondContext(JCNewClass clazz, TypeSymbol tsym, CheckContext checkContext) {
3464             return new Check.NestedCheckContext(checkContext) {
3465                 @Override
3466                 public void report(DiagnosticPosition _unused, JCDiagnostic details) {
3467                     enclosingContext.report(clazz.clazz,
3468                             diags.fragment(Fragments.CantApplyDiamond1(Fragments.Diamond(tsym), details)));
3469                 }
3470             };
3471         }
3472 
3473         void checkNewInnerClass(DiagnosticPosition pos, Env<AttrContext> env, Type type, boolean isSuper) {
3474             boolean isLocal = type.tsym.owner.kind == VAR || type.tsym.owner.kind == MTH;
3475             if ((type.tsym.flags() & (INTERFACE | ENUM | RECORD)) != 0 ||
3476                     (!isLocal && !type.tsym.isInner()) ||
3477                     (isSuper && env.enclClass.sym.isAnonymous())) {
3478                 // nothing to check
3479                 return;
3480             }
3481             Symbol res = isLocal ?
3482                     rs.findLocalClassOwner(env, type.tsym) :
3483                     rs.findSelfContaining(pos, env, type.getEnclosingType().tsym, isSuper);
3484             if (res.exists()) {
3485                 rs.accessBase(res, pos, env.enclClass.sym.type, names._this, true);
3486             } else {
3487                 log.error(pos, Errors.EnclClassRequired(type.tsym));
3488             }
3489         }
3490 
3491     /** Make an attributed null check tree.
3492      */
3493     public JCExpression makeNullCheck(JCExpression arg) {
3494         // optimization: new Outer() can never be null; skip null check
3495         if (arg.getTag() == NEWCLASS)
3496             return arg;
3497         // optimization: X.this is never null; skip null check
3498         Name name = TreeInfo.name(arg);
3499         if (name == names._this || name == names._super) return arg;
3500 
3501         JCTree.Tag optag = NULLCHK;
3502         JCUnary tree = make.at(arg.pos).Unary(optag, arg);
3503         tree.operator = operators.resolveUnary(arg, optag, arg.type);
3504         tree.type = arg.type;
3505         return tree;
3506     }
3507 
3508     public void visitNewArray(JCNewArray tree) {
3509         Type owntype = types.createErrorType(tree.type);
3510         Env<AttrContext> localEnv = env.dup(tree);
3511         Type elemtype;
3512         if (tree.elemtype != null) {
3513             elemtype = attribType(tree.elemtype, localEnv);
3514             chk.validate(tree.elemtype, localEnv);
3515             owntype = elemtype;
3516             for (List<JCExpression> l = tree.dims; l.nonEmpty(); l = l.tail) {
3517                 attribExpr(l.head, localEnv, syms.intType);
3518                 owntype = new ArrayType(owntype, syms.arrayClass);
3519             }
3520         } else {
3521             // we are seeing an untyped aggregate { ... }
3522             // this is allowed only if the prototype is an array
3523             if (pt().hasTag(ARRAY)) {
3524                 elemtype = types.elemtype(pt());
3525             } else {
3526                 if (!pt().hasTag(ERROR) &&
3527                         (env.info.enclVar == null || !env.info.enclVar.type.isErroneous())) {
3528                     log.error(tree.pos(),
3529                               Errors.IllegalInitializerForType(pt()));
3530                 }
3531                 elemtype = types.createErrorType(pt());
3532             }
3533         }
3534         if (tree.elems != null) {
3535             attribExprs(tree.elems, localEnv, elemtype);
3536             owntype = new ArrayType(elemtype, syms.arrayClass);
3537         }
3538         if (!types.isReifiable(elemtype))
3539             log.error(tree.pos(), Errors.GenericArrayCreation);
3540         result = check(tree, owntype, KindSelector.VAL, resultInfo);
3541     }
3542 
3543     /*
3544      * A lambda expression can only be attributed when a target-type is available.
3545      * In addition, if the target-type is that of a functional interface whose
3546      * descriptor contains inference variables in argument position the lambda expression
3547      * is 'stuck' (see DeferredAttr).
3548      */
3549     @Override
3550     public void visitLambda(final JCLambda that) {
3551         boolean wrongContext = false;
3552         if (pt().isErroneous() || (pt().hasTag(NONE) && pt() != Type.recoveryType)) {
3553             if (pt().hasTag(NONE) && (env.info.enclVar == null || !env.info.enclVar.type.isErroneous())) {
3554                 //lambda only allowed in assignment or method invocation/cast context
3555                 log.error(that.pos(), Errors.UnexpectedLambda);
3556             }
3557             resultInfo = recoveryInfo;
3558             wrongContext = true;
3559         }
3560         //create an environment for attribution of the lambda expression
3561         final Env<AttrContext> localEnv = lambdaEnv(that, env);
3562         boolean needsRecovery =
3563                 resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.CHECK;
3564         try {
3565             if (needsRecovery && rs.isSerializable(pt())) {
3566                 localEnv.info.isSerializable = true;
3567                 localEnv.info.isSerializableLambda = true;
3568             }
3569             List<Type> explicitParamTypes = null;
3570             if (that.paramKind == JCLambda.ParameterKind.EXPLICIT) {
3571                 //attribute lambda parameters
3572                 attribStats(that.params, localEnv);
3573                 explicitParamTypes = TreeInfo.types(that.params);
3574             }
3575 
3576             TargetInfo targetInfo = getTargetInfo(that, resultInfo, explicitParamTypes);
3577             Type currentTarget = targetInfo.target;
3578             Type lambdaType = targetInfo.descriptor;
3579 
3580             if (currentTarget.isErroneous()) {
3581                 result = that.type = currentTarget;
3582                 return;
3583             }
3584 
3585             setFunctionalInfo(localEnv, that, pt(), lambdaType, currentTarget, resultInfo.checkContext);
3586 
3587             if (lambdaType.hasTag(FORALL)) {
3588                 //lambda expression target desc cannot be a generic method
3589                 Fragment msg = Fragments.InvalidGenericLambdaTarget(lambdaType,
3590                                                                     kindName(currentTarget.tsym),
3591                                                                     currentTarget.tsym);
3592                 resultInfo.checkContext.report(that, diags.fragment(msg));
3593                 result = that.type = types.createErrorType(pt());
3594                 return;
3595             }
3596 
3597             if (that.paramKind == JCLambda.ParameterKind.IMPLICIT) {
3598                 //add param type info in the AST
3599                 List<Type> actuals = lambdaType.getParameterTypes();
3600                 List<JCVariableDecl> params = that.params;
3601 
3602                 boolean arityMismatch = false;
3603 
3604                 while (params.nonEmpty()) {
3605                     if (actuals.isEmpty()) {
3606                         //not enough actuals to perform lambda parameter inference
3607                         arityMismatch = true;
3608                     }
3609                     //reset previously set info
3610                     Type argType = arityMismatch ?
3611                             syms.errType :
3612                             actuals.head;
3613                     if (params.head.isImplicitlyTyped()) {
3614                         setSyntheticVariableType(params.head, argType);
3615                     }
3616                     params.head.sym = null;
3617                     actuals = actuals.isEmpty() ?
3618                             actuals :
3619                             actuals.tail;
3620                     params = params.tail;
3621                 }
3622 
3623                 //attribute lambda parameters
3624                 attribStats(that.params, localEnv);
3625 
3626                 if (arityMismatch) {
3627                     resultInfo.checkContext.report(that, diags.fragment(Fragments.IncompatibleArgTypesInLambda));
3628                         result = that.type = types.createErrorType(currentTarget);
3629                         return;
3630                 }
3631             }
3632 
3633             //from this point on, no recovery is needed; if we are in assignment context
3634             //we will be able to attribute the whole lambda body, regardless of errors;
3635             //if we are in a 'check' method context, and the lambda is not compatible
3636             //with the target-type, it will be recovered anyway in Attr.checkId
3637             needsRecovery = false;
3638 
3639             ResultInfo bodyResultInfo = localEnv.info.returnResult =
3640                     lambdaBodyResult(that, lambdaType, resultInfo);
3641 
3642             if (that.getBodyKind() == JCLambda.BodyKind.EXPRESSION) {
3643                 attribTree(that.getBody(), localEnv, bodyResultInfo);
3644             } else {
3645                 JCBlock body = (JCBlock)that.body;
3646                 if (body == breakTree &&
3647                         resultInfo.checkContext.deferredAttrContext().mode == AttrMode.CHECK) {
3648                     breakTreeFound(copyEnv(localEnv));
3649                 }
3650                 attribStats(body.stats, localEnv);
3651             }
3652 
3653             result = check(that, currentTarget, KindSelector.VAL, resultInfo);
3654 
3655             boolean isSpeculativeRound =
3656                     resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.SPECULATIVE;
3657 
3658             preFlow(that);
3659             flow.analyzeLambda(env, that, make, isSpeculativeRound);
3660 
3661             that.type = currentTarget; //avoids recovery at this stage
3662             checkLambdaCompatible(that, lambdaType, resultInfo.checkContext);
3663 
3664             if (!isSpeculativeRound) {
3665                 //add thrown types as bounds to the thrown types free variables if needed:
3666                 if (resultInfo.checkContext.inferenceContext().free(lambdaType.getThrownTypes())) {
3667                     List<Type> inferredThrownTypes = flow.analyzeLambdaThrownTypes(env, that, make);
3668                     if(!checkExConstraints(inferredThrownTypes, lambdaType.getThrownTypes(), resultInfo.checkContext.inferenceContext())) {
3669                         log.error(that, Errors.IncompatibleThrownTypesInMref(lambdaType.getThrownTypes()));
3670                     }
3671                 }
3672 
3673                 checkAccessibleTypes(that, localEnv, resultInfo.checkContext.inferenceContext(), lambdaType, currentTarget);
3674             }
3675             result = wrongContext ? that.type = types.createErrorType(pt())
3676                                   : check(that, currentTarget, KindSelector.VAL, resultInfo);
3677         } catch (Types.FunctionDescriptorLookupError ex) {
3678             JCDiagnostic cause = ex.getDiagnostic();
3679             resultInfo.checkContext.report(that, cause);
3680             result = that.type = types.createErrorType(pt());
3681             return;
3682         } catch (CompletionFailure cf) {
3683             chk.completionError(that.pos(), cf);
3684         } catch (Throwable t) {
3685             //when an unexpected exception happens, avoid attempts to attribute the same tree again
3686             //as that would likely cause the same exception again.
3687             needsRecovery = false;
3688             throw t;
3689         } finally {
3690             localEnv.info.scope.leave();
3691             if (needsRecovery) {
3692                 Type prevResult = result;
3693                 try {
3694                     attribTree(that, env, recoveryInfo);
3695                 } finally {
3696                     if (result == Type.recoveryType) {
3697                         result = prevResult;
3698                     }
3699                 }
3700             }
3701         }
3702     }
3703     //where
3704         class TargetInfo {
3705             Type target;
3706             Type descriptor;
3707 
3708             public TargetInfo(Type target, Type descriptor) {
3709                 this.target = target;
3710                 this.descriptor = descriptor;
3711             }
3712         }
3713 
3714         TargetInfo getTargetInfo(JCPolyExpression that, ResultInfo resultInfo, List<Type> explicitParamTypes) {
3715             Type lambdaType;
3716             Type currentTarget = resultInfo.pt;
3717             if (resultInfo.pt != Type.recoveryType) {
3718                 /* We need to adjust the target. If the target is an
3719                  * intersection type, for example: SAM & I1 & I2 ...
3720                  * the target will be updated to SAM
3721                  */
3722                 currentTarget = targetChecker.visit(currentTarget, that);
3723                 if (!currentTarget.isIntersection()) {
3724                     if (explicitParamTypes != null) {
3725                         currentTarget = infer.instantiateFunctionalInterface(that,
3726                                 currentTarget, explicitParamTypes, resultInfo.checkContext);
3727                     }
3728                     currentTarget = types.removeWildcards(currentTarget);
3729                     lambdaType = types.findDescriptorType(currentTarget);
3730                 } else {
3731                     IntersectionClassType ict = (IntersectionClassType)currentTarget;
3732                     ListBuffer<Type> components = new ListBuffer<>();
3733                     for (Type bound : ict.getExplicitComponents()) {
3734                         if (explicitParamTypes != null) {
3735                             try {
3736                                 bound = infer.instantiateFunctionalInterface(that,
3737                                         bound, explicitParamTypes, resultInfo.checkContext);
3738                             } catch (FunctionDescriptorLookupError t) {
3739                                 // do nothing
3740                             }
3741                         }
3742                         if (bound.tsym != syms.objectType.tsym && (!bound.isInterface() || (bound.tsym.flags() & ANNOTATION) != 0)) {
3743                             // bound must be j.l.Object or an interface, but not an annotation
3744                             reportIntersectionError(that, "not.an.intf.component", bound);
3745                         }
3746                         bound = types.removeWildcards(bound);
3747                         components.add(bound);
3748                     }
3749                     currentTarget = types.makeIntersectionType(components.toList());
3750                     currentTarget.tsym.flags_field |= INTERFACE;
3751                     lambdaType = types.findDescriptorType(currentTarget);
3752                 }
3753 
3754             } else {
3755                 currentTarget = Type.recoveryType;
3756                 lambdaType = fallbackDescriptorType(that);
3757             }
3758             if (that.hasTag(LAMBDA) && lambdaType.hasTag(FORALL)) {
3759                 //lambda expression target desc cannot be a generic method
3760                 Fragment msg = Fragments.InvalidGenericLambdaTarget(lambdaType,
3761                                                                     kindName(currentTarget.tsym),
3762                                                                     currentTarget.tsym);
3763                 resultInfo.checkContext.report(that, diags.fragment(msg));
3764                 currentTarget = types.createErrorType(pt());
3765             }
3766             return new TargetInfo(currentTarget, lambdaType);
3767         }
3768 
3769         private void reportIntersectionError(DiagnosticPosition pos, String key, Object... args) {
3770              resultInfo.checkContext.report(pos,
3771                  diags.fragment(Fragments.BadIntersectionTargetForFunctionalExpr(diags.fragment(key, args))));
3772         }
3773 
3774         void preFlow(JCLambda tree) {
3775             attrRecover.doRecovery();
3776             new PostAttrAnalyzer() {
3777                 @Override
3778                 public void scan(JCTree tree) {
3779                     if (tree == null ||
3780                             (tree.type != null &&
3781                             tree.type == Type.stuckType)) {
3782                         //don't touch stuck expressions!
3783                         return;
3784                     }
3785                     super.scan(tree);
3786                 }
3787 
3788                 @Override
3789                 public void visitClassDef(JCClassDecl that) {
3790                     // or class declaration trees!
3791                 }
3792 
3793                 public void visitLambda(JCLambda that) {
3794                     // or lambda expressions!
3795                 }
3796             }.scan(tree.body);
3797         }
3798 
3799         Types.MapVisitor<DiagnosticPosition> targetChecker = new Types.MapVisitor<DiagnosticPosition>() {
3800 
3801             @Override
3802             public Type visitClassType(ClassType t, DiagnosticPosition pos) {
3803                 return t.isIntersection() ?
3804                         visitIntersectionClassType((IntersectionClassType)t, pos) : t;
3805             }
3806 
3807             public Type visitIntersectionClassType(IntersectionClassType ict, DiagnosticPosition pos) {
3808                 types.findDescriptorSymbol(makeNotionalInterface(ict, pos));
3809                 return ict;
3810             }
3811 
3812             private TypeSymbol makeNotionalInterface(IntersectionClassType ict, DiagnosticPosition pos) {
3813                 ListBuffer<Type> targs = new ListBuffer<>();
3814                 ListBuffer<Type> supertypes = new ListBuffer<>();
3815                 for (Type i : ict.interfaces_field) {
3816                     if (i.isParameterized()) {
3817                         targs.appendList(i.tsym.type.allparams());
3818                     }
3819                     supertypes.append(i.tsym.type);
3820                 }
3821                 IntersectionClassType notionalIntf = types.makeIntersectionType(supertypes.toList());
3822                 notionalIntf.allparams_field = targs.toList();
3823                 notionalIntf.tsym.flags_field |= INTERFACE;
3824                 return notionalIntf.tsym;
3825             }
3826         };
3827 
3828         private Type fallbackDescriptorType(JCExpression tree) {
3829             switch (tree.getTag()) {
3830                 case LAMBDA:
3831                     JCLambda lambda = (JCLambda)tree;
3832                     List<Type> argtypes = List.nil();
3833                     for (JCVariableDecl param : lambda.params) {
3834                         argtypes = param.vartype != null && param.vartype.type != null ?
3835                                 argtypes.append(param.vartype.type) :
3836                                 argtypes.append(syms.errType);
3837                     }
3838                     return new MethodType(argtypes, Type.recoveryType,
3839                             List.of(syms.throwableType), syms.methodClass);
3840                 case REFERENCE:
3841                     return new MethodType(List.nil(), Type.recoveryType,
3842                             List.of(syms.throwableType), syms.methodClass);
3843                 default:
3844                     Assert.error("Cannot get here!");
3845             }
3846             return null;
3847         }
3848 
3849         private void checkAccessibleTypes(final DiagnosticPosition pos, final Env<AttrContext> env,
3850                 final InferenceContext inferenceContext, final Type... ts) {
3851             checkAccessibleTypes(pos, env, inferenceContext, List.from(ts));
3852         }
3853 
3854         private void checkAccessibleTypes(final DiagnosticPosition pos, final Env<AttrContext> env,
3855                 final InferenceContext inferenceContext, final List<Type> ts) {
3856             if (inferenceContext.free(ts)) {
3857                 inferenceContext.addFreeTypeListener(ts,
3858                         solvedContext -> checkAccessibleTypes(pos, env, solvedContext, solvedContext.asInstTypes(ts)));
3859             } else {
3860                 for (Type t : ts) {
3861                     rs.checkAccessibleType(env, t);
3862                 }
3863             }
3864         }
3865 
3866         /**
3867          * Lambda/method reference have a special check context that ensures
3868          * that i.e. a lambda return type is compatible with the expected
3869          * type according to both the inherited context and the assignment
3870          * context.
3871          */
3872         class FunctionalReturnContext extends Check.NestedCheckContext {
3873 
3874             FunctionalReturnContext(CheckContext enclosingContext) {
3875                 super(enclosingContext);
3876             }
3877 
3878             @Override
3879             public boolean compatible(Type found, Type req, Warner warn) {
3880                 //return type must be compatible in both current context and assignment context
3881                 return chk.basicHandler.compatible(inferenceContext().asUndetVar(found), inferenceContext().asUndetVar(req), warn);
3882             }
3883 
3884             @Override
3885             public void report(DiagnosticPosition pos, JCDiagnostic details) {
3886                 enclosingContext.report(pos, diags.fragment(Fragments.IncompatibleRetTypeInLambda(details)));
3887             }
3888         }
3889 
3890         class ExpressionLambdaReturnContext extends FunctionalReturnContext {
3891 
3892             JCExpression expr;
3893             boolean expStmtExpected;
3894 
3895             ExpressionLambdaReturnContext(JCExpression expr, CheckContext enclosingContext) {
3896                 super(enclosingContext);
3897                 this.expr = expr;
3898             }
3899 
3900             @Override
3901             public void report(DiagnosticPosition pos, JCDiagnostic details) {
3902                 if (expStmtExpected) {
3903                     enclosingContext.report(pos, diags.fragment(Fragments.StatExprExpected));
3904                 } else {
3905                     super.report(pos, details);
3906                 }
3907             }
3908 
3909             @Override
3910             public boolean compatible(Type found, Type req, Warner warn) {
3911                 //a void return is compatible with an expression statement lambda
3912                 if (req.hasTag(VOID)) {
3913                     expStmtExpected = true;
3914                     return TreeInfo.isExpressionStatement(expr);
3915                 } else {
3916                     return super.compatible(found, req, warn);
3917                 }
3918             }
3919         }
3920 
3921         ResultInfo lambdaBodyResult(JCLambda that, Type descriptor, ResultInfo resultInfo) {
3922             FunctionalReturnContext funcContext = that.getBodyKind() == JCLambda.BodyKind.EXPRESSION ?
3923                     new ExpressionLambdaReturnContext((JCExpression)that.getBody(), resultInfo.checkContext) :
3924                     new FunctionalReturnContext(resultInfo.checkContext);
3925 
3926             return descriptor.getReturnType() == Type.recoveryType ?
3927                     recoveryInfo :
3928                     new ResultInfo(KindSelector.VAL,
3929                             descriptor.getReturnType(), funcContext);
3930         }
3931 
3932         /**
3933         * Lambda compatibility. Check that given return types, thrown types, parameter types
3934         * are compatible with the expected functional interface descriptor. This means that:
3935         * (i) parameter types must be identical to those of the target descriptor; (ii) return
3936         * types must be compatible with the return type of the expected descriptor.
3937         */
3938         void checkLambdaCompatible(JCLambda tree, Type descriptor, CheckContext checkContext) {
3939             Type returnType = checkContext.inferenceContext().asUndetVar(descriptor.getReturnType());
3940 
3941             //return values have already been checked - but if lambda has no return
3942             //values, we must ensure that void/value compatibility is correct;
3943             //this amounts at checking that, if a lambda body can complete normally,
3944             //the descriptor's return type must be void
3945             if (tree.getBodyKind() == JCLambda.BodyKind.STATEMENT && tree.canCompleteNormally &&
3946                     !returnType.hasTag(VOID) && returnType != Type.recoveryType) {
3947                 Fragment msg =
3948                         Fragments.IncompatibleRetTypeInLambda(Fragments.MissingRetVal(returnType));
3949                 checkContext.report(tree,
3950                                     diags.fragment(msg));
3951             }
3952 
3953             List<Type> argTypes = checkContext.inferenceContext().asUndetVars(descriptor.getParameterTypes());
3954             if (!types.isSameTypes(argTypes, TreeInfo.types(tree.params))) {
3955                 checkContext.report(tree, diags.fragment(Fragments.IncompatibleArgTypesInLambda));
3956             }
3957         }
3958 
3959         /* This method returns an environment to be used to attribute a lambda
3960          * expression.
3961          *
3962          * The owner of this environment is a method symbol. If the current owner
3963          * is not a method (e.g. if the lambda occurs in a field initializer), then
3964          * a synthetic method symbol owner is created.
3965          */
3966         public Env<AttrContext> lambdaEnv(JCLambda that, Env<AttrContext> env) {
3967             Env<AttrContext> lambdaEnv;
3968             Symbol owner = env.info.scope.owner;
3969             if (owner.kind == VAR && owner.owner.kind == TYP) {
3970                 // If the lambda is nested in a field initializer, we need to create a fake init method.
3971                 // Uniqueness of this symbol is not important (as e.g. annotations will be added on the
3972                 // init symbol's owner).
3973                 ClassSymbol enclClass = owner.enclClass();
3974                 Name initName = owner.isStatic() ? names.clinit : names.init;
3975                 MethodSymbol initSym = new MethodSymbol(BLOCK | (owner.isStatic() ? STATIC : 0) | SYNTHETIC | PRIVATE,
3976                         initName, initBlockType, enclClass);
3977                 initSym.params = List.nil();
3978                 lambdaEnv = env.dup(that, env.info.dup(env.info.scope.dupUnshared(initSym)));
3979             } else {
3980                 lambdaEnv = env.dup(that, env.info.dup(env.info.scope.dup()));
3981             }
3982             lambdaEnv.info.yieldResult = null;
3983             lambdaEnv.info.isLambda = true;
3984             return lambdaEnv;
3985         }
3986 
3987     @Override
3988     public void visitReference(final JCMemberReference that) {
3989         if (pt().isErroneous() || (pt().hasTag(NONE) && pt() != Type.recoveryType)) {
3990             if (pt().hasTag(NONE) && (env.info.enclVar == null || !env.info.enclVar.type.isErroneous())) {
3991                 //method reference only allowed in assignment or method invocation/cast context
3992                 log.error(that.pos(), Errors.UnexpectedMref);
3993             }
3994             result = that.type = types.createErrorType(pt());
3995             return;
3996         }
3997         final Env<AttrContext> localEnv = env.dup(that);
3998         try {
3999             //attribute member reference qualifier - if this is a constructor
4000             //reference, the expected kind must be a type
4001             Type exprType = attribTree(that.expr, env, memberReferenceQualifierResult(that));
4002 
4003             if (that.getMode() == JCMemberReference.ReferenceMode.NEW) {
4004                 exprType = chk.checkConstructorRefType(that.expr, exprType);
4005                 if (!exprType.isErroneous() &&
4006                     exprType.isRaw() &&
4007                     that.typeargs != null) {
4008                     log.error(that.expr.pos(),
4009                               Errors.InvalidMref(Kinds.kindName(that.getMode()),
4010                                                  Fragments.MrefInferAndExplicitParams));
4011                     exprType = types.createErrorType(exprType);
4012                 }
4013             }
4014 
4015             if (exprType.isErroneous()) {
4016                 //if the qualifier expression contains problems,
4017                 //give up attribution of method reference
4018                 result = that.type = exprType;
4019                 return;
4020             }
4021 
4022             if (TreeInfo.isStaticSelector(that.expr, names)) {
4023                 //if the qualifier is a type, validate it; raw warning check is
4024                 //omitted as we don't know at this stage as to whether this is a
4025                 //raw selector (because of inference)
4026                 chk.validate(that.expr, env, false);
4027             } else {
4028                 Symbol lhsSym = TreeInfo.symbol(that.expr);
4029                 localEnv.info.selectSuper = lhsSym != null && lhsSym.name == names._super;
4030             }
4031             //attrib type-arguments
4032             List<Type> typeargtypes = List.nil();
4033             if (that.typeargs != null) {
4034                 typeargtypes = attribTypes(that.typeargs, localEnv);
4035             }
4036 
4037             boolean isTargetSerializable =
4038                     resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.CHECK &&
4039                     rs.isSerializable(pt());
4040             TargetInfo targetInfo = getTargetInfo(that, resultInfo, null);
4041             Type currentTarget = targetInfo.target;
4042             Type desc = targetInfo.descriptor;
4043 
4044             setFunctionalInfo(localEnv, that, pt(), desc, currentTarget, resultInfo.checkContext);
4045             List<Type> argtypes = desc.getParameterTypes();
4046             Resolve.MethodCheck referenceCheck = rs.resolveMethodCheck;
4047 
4048             if (resultInfo.checkContext.inferenceContext().free(argtypes)) {
4049                 referenceCheck = rs.new MethodReferenceCheck(resultInfo.checkContext.inferenceContext());
4050             }
4051 
4052             Pair<Symbol, Resolve.ReferenceLookupHelper> refResult = null;
4053             List<Type> saved_undet = resultInfo.checkContext.inferenceContext().save();
4054             try {
4055                 refResult = rs.resolveMemberReference(localEnv, that, that.expr.type,
4056                         that.name, argtypes, typeargtypes, targetInfo.descriptor, referenceCheck,
4057                         resultInfo.checkContext.inferenceContext(), rs.basicReferenceChooser);
4058             } finally {
4059                 resultInfo.checkContext.inferenceContext().rollback(saved_undet);
4060             }
4061 
4062             Symbol refSym = refResult.fst;
4063             Resolve.ReferenceLookupHelper lookupHelper = refResult.snd;
4064 
4065             /** this switch will need to go away and be replaced by the new RESOLUTION_TARGET testing
4066              *  JDK-8075541
4067              */
4068             if (refSym.kind != MTH) {
4069                 boolean targetError;
4070                 switch (refSym.kind) {
4071                     case ABSENT_MTH:
4072                         targetError = false;
4073                         break;
4074                     case WRONG_MTH:
4075                     case WRONG_MTHS:
4076                     case AMBIGUOUS:
4077                     case HIDDEN:
4078                     case STATICERR:
4079                         targetError = true;
4080                         break;
4081                     default:
4082                         Assert.error("unexpected result kind " + refSym.kind);
4083                         targetError = false;
4084                 }
4085 
4086                 JCDiagnostic detailsDiag = ((Resolve.ResolveError)refSym.baseSymbol())
4087                         .getDiagnostic(JCDiagnostic.DiagnosticType.FRAGMENT,
4088                                 that, exprType.tsym, exprType, that.name, argtypes, typeargtypes);
4089 
4090                 JCDiagnostic diag = diags.create(log.currentSource(), that,
4091                         targetError ?
4092                             Fragments.InvalidMref(Kinds.kindName(that.getMode()), detailsDiag) :
4093                             Errors.InvalidMref(Kinds.kindName(that.getMode()), detailsDiag));
4094 
4095                 if (targetError && currentTarget == Type.recoveryType) {
4096                     //a target error doesn't make sense during recovery stage
4097                     //as we don't know what actual parameter types are
4098                     result = that.type = currentTarget;
4099                     return;
4100                 } else {
4101                     if (targetError) {
4102                         resultInfo.checkContext.report(that, diag);
4103                     } else {
4104                         log.report(diag);
4105                     }
4106                     result = that.type = types.createErrorType(currentTarget);
4107                     return;
4108                 }
4109             }
4110 
4111             that.sym = refSym.isConstructor() ? refSym.baseSymbol() : refSym;
4112             that.kind = lookupHelper.referenceKind(that.sym);
4113             that.ownerAccessible = rs.isAccessible(localEnv, that.sym.enclClass());
4114 
4115             if (desc.getReturnType() == Type.recoveryType) {
4116                 // stop here
4117                 result = that.type = currentTarget;
4118                 return;
4119             }
4120 
4121             if (!env.info.attributionMode.isSpeculative && that.getMode() == JCMemberReference.ReferenceMode.NEW) {
4122                 checkNewInnerClass(that.pos(), env, exprType, false);
4123             }
4124 
4125             if (resultInfo.checkContext.deferredAttrContext().mode == AttrMode.CHECK) {
4126 
4127                 if (that.getMode() == ReferenceMode.INVOKE &&
4128                         TreeInfo.isStaticSelector(that.expr, names) &&
4129                         that.kind.isUnbound() &&
4130                         lookupHelper.site.isRaw()) {
4131                     chk.checkRaw(that.expr, localEnv);
4132                 }
4133 
4134                 if (that.sym.isStatic() && TreeInfo.isStaticSelector(that.expr, names) &&
4135                         exprType.getTypeArguments().nonEmpty()) {
4136                     //static ref with class type-args
4137                     log.error(that.expr.pos(),
4138                               Errors.InvalidMref(Kinds.kindName(that.getMode()),
4139                                                  Fragments.StaticMrefWithTargs));
4140                     result = that.type = types.createErrorType(currentTarget);
4141                     return;
4142                 }
4143 
4144                 if (!refSym.isStatic() && that.kind == JCMemberReference.ReferenceKind.SUPER) {
4145                     // Check that super-qualified symbols are not abstract (JLS)
4146                     rs.checkNonAbstract(that.pos(), that.sym);
4147                 }
4148 
4149                 if (isTargetSerializable) {
4150                     chk.checkAccessFromSerializableElement(that, true);
4151                 }
4152             }
4153 
4154             ResultInfo checkInfo =
4155                     resultInfo.dup(newMethodTemplate(
4156                         desc.getReturnType().hasTag(VOID) ? Type.noType : desc.getReturnType(),
4157                         that.kind.isUnbound() ? argtypes.tail : argtypes, typeargtypes),
4158                         new FunctionalReturnContext(resultInfo.checkContext), CheckMode.NO_TREE_UPDATE);
4159 
4160             Type refType = checkId(that, lookupHelper.site, refSym, localEnv, checkInfo);
4161 
4162             if (that.kind.isUnbound() &&
4163                     resultInfo.checkContext.inferenceContext().free(argtypes.head)) {
4164                 //re-generate inference constraints for unbound receiver
4165                 if (!types.isSubtype(resultInfo.checkContext.inferenceContext().asUndetVar(argtypes.head), exprType)) {
4166                     //cannot happen as this has already been checked - we just need
4167                     //to regenerate the inference constraints, as that has been lost
4168                     //as a result of the call to inferenceContext.save()
4169                     Assert.error("Can't get here");
4170                 }
4171             }
4172 
4173             if (!refType.isErroneous()) {
4174                 refType = types.createMethodTypeWithReturn(refType,
4175                         adjustMethodReturnType(refSym, lookupHelper.site, that.name, checkInfo.pt.getParameterTypes(), refType.getReturnType()));
4176             }
4177 
4178             //go ahead with standard method reference compatibility check - note that param check
4179             //is a no-op (as this has been taken care during method applicability)
4180             boolean isSpeculativeRound =
4181                     resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.SPECULATIVE;
4182 
4183             that.type = currentTarget; //avoids recovery at this stage
4184             checkReferenceCompatible(that, desc, refType, resultInfo.checkContext, isSpeculativeRound);
4185             if (!isSpeculativeRound) {
4186                 checkAccessibleTypes(that, localEnv, resultInfo.checkContext.inferenceContext(), desc, currentTarget);
4187             }
4188             chk.checkRequiresIdentity(that, localEnv.info.lint);
4189             result = check(that, currentTarget, KindSelector.VAL, resultInfo);
4190         } catch (Types.FunctionDescriptorLookupError ex) {
4191             JCDiagnostic cause = ex.getDiagnostic();
4192             resultInfo.checkContext.report(that, cause);
4193             result = that.type = types.createErrorType(pt());
4194             return;
4195         }
4196     }
4197     //where
4198         ResultInfo memberReferenceQualifierResult(JCMemberReference tree) {
4199             //if this is a constructor reference, the expected kind must be a type
4200             return new ResultInfo(tree.getMode() == ReferenceMode.INVOKE ?
4201                                   KindSelector.VAL_TYP : KindSelector.TYP,
4202                                   Type.noType);
4203         }
4204 
4205 
4206     @SuppressWarnings("fallthrough")
4207     void checkReferenceCompatible(JCMemberReference tree, Type descriptor, Type refType, CheckContext checkContext, boolean speculativeAttr) {
4208         InferenceContext inferenceContext = checkContext.inferenceContext();
4209         Type returnType = inferenceContext.asUndetVar(descriptor.getReturnType());
4210 
4211         Type resType;
4212         switch (tree.getMode()) {
4213             case NEW:
4214                 if (!tree.expr.type.isRaw()) {
4215                     resType = tree.expr.type;
4216                     break;
4217                 }
4218             default:
4219                 resType = refType.getReturnType();
4220         }
4221 
4222         Type incompatibleReturnType = resType;
4223 
4224         if (returnType.hasTag(VOID)) {
4225             incompatibleReturnType = null;
4226         }
4227 
4228         if (!returnType.hasTag(VOID) && !resType.hasTag(VOID)) {
4229             Type capturedResType = captureMRefReturnType ? types.capture(resType) : resType;
4230             if (resType.isErroneous() ||
4231                     new FunctionalReturnContext(checkContext).compatible(capturedResType, returnType,
4232                             checkContext.checkWarner(tree, capturedResType, returnType))) {
4233                 incompatibleReturnType = null;
4234             }
4235         }
4236 
4237         if (incompatibleReturnType != null) {
4238             Fragment msg =
4239                     Fragments.IncompatibleRetTypeInMref(Fragments.InconvertibleTypes(resType, descriptor.getReturnType()));
4240             checkContext.report(tree, diags.fragment(msg));
4241         } else {
4242             if (inferenceContext.free(refType)) {
4243                 // we need to wait for inference to finish and then replace inference vars in the referent type
4244                 inferenceContext.addFreeTypeListener(List.of(refType),
4245                         instantiatedContext -> {
4246                             tree.referentType = instantiatedContext.asInstType(refType);
4247                         });
4248             } else {
4249                 tree.referentType = refType;
4250             }
4251         }
4252 
4253         if (!speculativeAttr) {
4254             if (!checkExConstraints(refType.getThrownTypes(), descriptor.getThrownTypes(), inferenceContext)) {
4255                 log.error(tree, Errors.IncompatibleThrownTypesInMref(refType.getThrownTypes()));
4256             }
4257         }
4258     }
4259 
4260     boolean checkExConstraints(
4261             List<Type> thrownByFuncExpr,
4262             List<Type> thrownAtFuncType,
4263             InferenceContext inferenceContext) {
4264         /** 18.2.5: Otherwise, let E1, ..., En be the types in the function type's throws clause that
4265          *  are not proper types
4266          */
4267         List<Type> nonProperList = thrownAtFuncType.stream()
4268                 .filter(e -> inferenceContext.free(e)).collect(List.collector());
4269         List<Type> properList = thrownAtFuncType.diff(nonProperList);
4270 
4271         /** Let X1,...,Xm be the checked exception types that the lambda body can throw or
4272          *  in the throws clause of the invocation type of the method reference's compile-time
4273          *  declaration
4274          */
4275         List<Type> checkedList = thrownByFuncExpr.stream()
4276                 .filter(e -> chk.isChecked(e)).collect(List.collector());
4277 
4278         /** If n = 0 (the function type's throws clause consists only of proper types), then
4279          *  if there exists some i (1 <= i <= m) such that Xi is not a subtype of any proper type
4280          *  in the throws clause, the constraint reduces to false; otherwise, the constraint
4281          *  reduces to true
4282          */
4283         ListBuffer<Type> uncaughtByProperTypes = new ListBuffer<>();
4284         for (Type checked : checkedList) {
4285             boolean isSubtype = false;
4286             for (Type proper : properList) {
4287                 if (types.isSubtype(checked, proper)) {
4288                     isSubtype = true;
4289                     break;
4290                 }
4291             }
4292             if (!isSubtype) {
4293                 uncaughtByProperTypes.add(checked);
4294             }
4295         }
4296 
4297         if (nonProperList.isEmpty() && !uncaughtByProperTypes.isEmpty()) {
4298             return false;
4299         }
4300 
4301         /** If n > 0, the constraint reduces to a set of subtyping constraints:
4302          *  for all i (1 <= i <= m), if Xi is not a subtype of any proper type in the
4303          *  throws clause, then the constraints include, for all j (1 <= j <= n), <Xi <: Ej>
4304          */
4305         List<Type> nonProperAsUndet = inferenceContext.asUndetVars(nonProperList);
4306         uncaughtByProperTypes.forEach(checkedEx -> {
4307             nonProperAsUndet.forEach(nonProper -> {
4308                 types.isSubtype(checkedEx, nonProper);
4309             });
4310         });
4311 
4312         /** In addition, for all j (1 <= j <= n), the constraint reduces to the bound throws Ej
4313          */
4314         nonProperAsUndet.stream()
4315                 .filter(t -> t.hasTag(UNDETVAR))
4316                 .forEach(t -> ((UndetVar)t).setThrow());
4317         return true;
4318     }
4319 
4320     /**
4321      * Set functional type info on the underlying AST. Note: as the target descriptor
4322      * might contain inference variables, we might need to register an hook in the
4323      * current inference context.
4324      */
4325     private void setFunctionalInfo(final Env<AttrContext> env, final JCFunctionalExpression fExpr,
4326             final Type pt, final Type descriptorType, final Type primaryTarget, final CheckContext checkContext) {
4327         if (checkContext.inferenceContext().free(descriptorType)) {
4328             checkContext.inferenceContext().addFreeTypeListener(List.of(pt, descriptorType),
4329                     inferenceContext -> setFunctionalInfo(env, fExpr, pt, inferenceContext.asInstType(descriptorType),
4330                     inferenceContext.asInstType(primaryTarget), checkContext));
4331         } else {
4332             fExpr.owner = env.info.scope.owner;
4333             if (pt.hasTag(CLASS)) {
4334                 fExpr.target = primaryTarget;
4335             }
4336             if (checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.CHECK &&
4337                     pt != Type.recoveryType) {
4338                 //check that functional interface class is well-formed
4339                 try {
4340                     /* Types.makeFunctionalInterfaceClass() may throw an exception
4341                      * when it's executed post-inference. See the listener code
4342                      * above.
4343                      */
4344                     ClassSymbol csym = types.makeFunctionalInterfaceClass(env,
4345                             names.empty, fExpr.target, ABSTRACT);
4346                     if (csym != null) {
4347                         chk.checkImplementations(env.tree, csym, csym);
4348                         try {
4349                             //perform an additional functional interface check on the synthetic class,
4350                             //as there may be spurious errors for raw targets - because of existing issues
4351                             //with membership and inheritance (see JDK-8074570).
4352                             csym.flags_field |= INTERFACE;
4353                             types.findDescriptorType(csym.type);
4354                         } catch (FunctionDescriptorLookupError err) {
4355                             resultInfo.checkContext.report(fExpr,
4356                                     diags.fragment(Fragments.NoSuitableFunctionalIntfInst(fExpr.target)));
4357                         }
4358                     }
4359                 } catch (Types.FunctionDescriptorLookupError ex) {
4360                     JCDiagnostic cause = ex.getDiagnostic();
4361                     resultInfo.checkContext.report(env.tree, cause);
4362                 }
4363             }
4364         }
4365     }
4366 
4367     public void visitParens(JCParens tree) {
4368         Type owntype = attribTree(tree.expr, env, resultInfo);
4369         result = check(tree, owntype, pkind(), resultInfo);
4370         Symbol sym = TreeInfo.symbol(tree);
4371         if (sym != null && sym.kind.matches(KindSelector.TYP_PCK) && sym.kind != Kind.ERR)
4372             log.error(tree.pos(), Errors.IllegalParenthesizedExpression);
4373     }
4374 
4375     public void visitAssign(JCAssign tree) {
4376         Type owntype = attribTree(tree.lhs, env.dup(tree), varAssignmentInfo);
4377         Type capturedType = capture(owntype);
4378         attribExpr(tree.rhs, env, owntype);
4379         result = check(tree, capturedType, KindSelector.VAL, resultInfo);
4380     }
4381 
4382     public void visitAssignop(JCAssignOp tree) {
4383         // Attribute arguments.
4384         Type owntype = attribTree(tree.lhs, env, varAssignmentInfo);
4385         Type operand = attribExpr(tree.rhs, env);
4386         // Find operator.
4387         Symbol operator = tree.operator = operators.resolveBinary(tree, tree.getTag().noAssignOp(), owntype, operand);
4388         if (operator != operators.noOpSymbol &&
4389                 !owntype.isErroneous() &&
4390                 !operand.isErroneous()) {
4391             chk.checkDivZero(tree.rhs.pos(), operator, operand);
4392             chk.checkCastable(tree.rhs.pos(),
4393                               operator.type.getReturnType(),
4394                               owntype);
4395             chk.checkLossOfPrecision(tree.rhs.pos(), operand, owntype);
4396             chk.checkOutOfRangeShift(tree.rhs.pos(), operator, operand);
4397         }
4398         result = check(tree, owntype, KindSelector.VAL, resultInfo);
4399     }
4400 
4401     public void visitUnary(JCUnary tree) {
4402         // Attribute arguments.
4403         Type argtype = (tree.getTag().isIncOrDecUnaryOp())
4404             ? attribTree(tree.arg, env, varAssignmentInfo)
4405             : chk.checkNonVoid(tree.arg.pos(), attribExpr(tree.arg, env));
4406 
4407         // Find operator.
4408         OperatorSymbol operator = tree.operator = operators.resolveUnary(tree, tree.getTag(), argtype);
4409         Type owntype = types.createErrorType(tree.type);
4410         if (operator != operators.noOpSymbol &&
4411                 !argtype.isErroneous()) {
4412             owntype = (tree.getTag().isIncOrDecUnaryOp())
4413                 ? tree.arg.type
4414                 : operator.type.getReturnType();
4415             int opc = operator.opcode;
4416 
4417             // If the argument is constant, fold it.
4418             if (argtype.constValue() != null) {
4419                 Type ctype = cfolder.fold1(opc, argtype);
4420                 if (ctype != null) {
4421                     owntype = cfolder.coerce(ctype, owntype);
4422                 }
4423             }
4424         }
4425         result = check(tree, owntype, KindSelector.VAL, resultInfo);
4426         matchBindings = matchBindingsComputer.unary(tree, matchBindings);
4427     }
4428 
4429     public void visitBinary(JCBinary tree) {
4430         // Attribute arguments.
4431         Type left = chk.checkNonVoid(tree.lhs.pos(), attribExpr(tree.lhs, env));
4432         // x && y
4433         // include x's bindings when true in y
4434 
4435         // x || y
4436         // include x's bindings when false in y
4437 
4438         MatchBindings lhsBindings = matchBindings;
4439         List<BindingSymbol> propagatedBindings;
4440         switch (tree.getTag()) {
4441             case AND:
4442                 propagatedBindings = lhsBindings.bindingsWhenTrue;
4443                 break;
4444             case OR:
4445                 propagatedBindings = lhsBindings.bindingsWhenFalse;
4446                 break;
4447             default:
4448                 propagatedBindings = List.nil();
4449                 break;
4450         }
4451         Env<AttrContext> rhsEnv = bindingEnv(env, propagatedBindings);
4452         Type right;
4453         try {
4454             right = chk.checkNonVoid(tree.rhs.pos(), attribExpr(tree.rhs, rhsEnv));
4455         } finally {
4456             rhsEnv.info.scope.leave();
4457         }
4458 
4459         matchBindings = matchBindingsComputer.binary(tree, lhsBindings, matchBindings);
4460 
4461         // Find operator.
4462         OperatorSymbol operator = tree.operator = operators.resolveBinary(tree, tree.getTag(), left, right);
4463         Type owntype = types.createErrorType(tree.type);
4464         if (operator != operators.noOpSymbol &&
4465                 !left.isErroneous() &&
4466                 !right.isErroneous()) {
4467             owntype = operator.type.getReturnType();
4468             int opc = operator.opcode;
4469             // If both arguments are constants, fold them.
4470             if (left.constValue() != null && right.constValue() != null) {
4471                 Type ctype = cfolder.fold2(opc, left, right);
4472                 if (ctype != null) {
4473                     owntype = cfolder.coerce(ctype, owntype);
4474                 }
4475             }
4476 
4477             // Check that argument types of a reference ==, != are
4478             // castable to each other, (JLS 15.21).  Note: unboxing
4479             // comparisons will not have an acmp* opc at this point.
4480             if ((opc == ByteCodes.if_acmpeq || opc == ByteCodes.if_acmpne)) {
4481                 if (!types.isCastable(left, right, new Warner(tree.pos()))) {
4482                     log.error(tree.pos(), Errors.IncomparableTypes(left, right));
4483                 }
4484             }
4485 
4486             chk.checkDivZero(tree.rhs.pos(), operator, right);
4487             chk.checkOutOfRangeShift(tree.rhs.pos(), operator, right);
4488         }
4489         result = check(tree, owntype, KindSelector.VAL, resultInfo);
4490     }
4491 
4492     public void visitTypeCast(final JCTypeCast tree) {
4493         Type clazztype = attribType(tree.clazz, env);
4494         chk.validate(tree.clazz, env, false);
4495         chk.checkRequiresIdentity(tree, env.info.lint);
4496         //a fresh environment is required for 292 inference to work properly ---
4497         //see Infer.instantiatePolymorphicSignatureInstance()
4498         Env<AttrContext> localEnv = env.dup(tree);
4499         //should we propagate the target type?
4500         final ResultInfo castInfo;
4501         JCExpression expr = TreeInfo.skipParens(tree.expr);
4502         boolean isPoly = (expr.hasTag(LAMBDA) || expr.hasTag(REFERENCE));
4503         if (isPoly) {
4504             //expression is a poly - we need to propagate target type info
4505             castInfo = new ResultInfo(KindSelector.VAL, clazztype,
4506                                       new Check.NestedCheckContext(resultInfo.checkContext) {
4507                 @Override
4508                 public boolean compatible(Type found, Type req, Warner warn) {
4509                     return types.isCastable(found, req, warn);
4510                 }
4511             });
4512         } else {
4513             //standalone cast - target-type info is not propagated
4514             castInfo = unknownExprInfo;
4515         }
4516         Type exprtype = attribTree(tree.expr, localEnv, castInfo);
4517         Type owntype = isPoly ? clazztype : chk.checkCastable(tree.expr.pos(), exprtype, clazztype);
4518         if (exprtype.constValue() != null)
4519             owntype = cfolder.coerce(exprtype, owntype);
4520         result = check(tree, capture(owntype), KindSelector.VAL, resultInfo);
4521         if (!isPoly)
4522             chk.checkRedundantCast(localEnv, tree);
4523     }
4524 
4525     public void visitTypeTest(JCInstanceOf tree) {
4526         Type exprtype = attribExpr(tree.expr, env);
4527         if (exprtype.isPrimitive()) {
4528             preview.checkSourceLevel(tree.expr.pos(), Feature.PRIMITIVE_PATTERNS);
4529         } else {
4530             exprtype = chk.checkNullOrRefType(
4531                     tree.expr.pos(), exprtype);
4532         }
4533         Type clazztype;
4534         JCTree typeTree;
4535         if (tree.pattern.getTag() == BINDINGPATTERN ||
4536             tree.pattern.getTag() == RECORDPATTERN) {
4537             attribExpr(tree.pattern, env, exprtype);
4538             clazztype = tree.pattern.type;
4539             if (types.isSubtype(exprtype, clazztype) &&
4540                 !exprtype.isErroneous() && !clazztype.isErroneous() &&
4541                 tree.pattern.getTag() != RECORDPATTERN) {
4542                 if (!allowUnconditionalPatternsInstanceOf) {
4543                     log.error(tree.pos(), Feature.UNCONDITIONAL_PATTERN_IN_INSTANCEOF.error(this.sourceName));
4544                 }
4545             }
4546             typeTree = TreeInfo.primaryPatternTypeTree((JCPattern) tree.pattern);
4547         } else {
4548             clazztype = attribType(tree.pattern, env);
4549             typeTree = tree.pattern;
4550             chk.validate(typeTree, env, false);
4551         }
4552         if (clazztype.isPrimitive()) {
4553             preview.checkSourceLevel(tree.pattern.pos(), Feature.PRIMITIVE_PATTERNS);
4554         } else {
4555             if (!clazztype.hasTag(TYPEVAR)) {
4556                 clazztype = chk.checkClassOrArrayType(typeTree.pos(), clazztype);
4557             }
4558             if (!clazztype.isErroneous() && !types.isReifiable(clazztype)) {
4559                 boolean valid = false;
4560                 if (allowReifiableTypesInInstanceof) {
4561                     valid = checkCastablePattern(tree.expr.pos(), exprtype, clazztype);
4562                 } else {
4563                     log.error(tree.pos(), Feature.REIFIABLE_TYPES_INSTANCEOF.error(this.sourceName));
4564                     allowReifiableTypesInInstanceof = true;
4565                 }
4566                 if (!valid) {
4567                     clazztype = types.createErrorType(clazztype);
4568                 }
4569             }
4570         }
4571         chk.checkCastable(tree.expr.pos(), exprtype, clazztype);
4572         result = check(tree, syms.booleanType, KindSelector.VAL, resultInfo);
4573     }
4574 
4575     private boolean checkCastablePattern(DiagnosticPosition pos,
4576                                          Type exprType,
4577                                          Type pattType) {
4578         Warner warner = new Warner();
4579         // if any type is erroneous, the problem is reported elsewhere
4580         if (exprType.isErroneous() || pattType.isErroneous()) {
4581             return false;
4582         }
4583         if (!types.isCastable(exprType, pattType, warner)) {
4584             chk.basicHandler.report(pos,
4585                     diags.fragment(Fragments.InconvertibleTypes(exprType, pattType)));
4586             return false;
4587         } else if ((exprType.isPrimitive() || pattType.isPrimitive()) &&
4588                 (!exprType.isPrimitive() || !pattType.isPrimitive() || !types.isSameType(exprType, pattType))) {
4589             preview.checkSourceLevel(pos, Feature.PRIMITIVE_PATTERNS);
4590             return true;
4591         } else if (warner.hasLint(LintCategory.UNCHECKED)) {
4592             log.error(pos,
4593                     Errors.InstanceofReifiableNotSafe(exprType, pattType));
4594             return false;
4595         } else {
4596             return true;
4597         }
4598     }
4599 
4600     @Override
4601     public void visitAnyPattern(JCAnyPattern tree) {
4602         result = tree.type = resultInfo.pt;
4603     }
4604 
4605     public void visitBindingPattern(JCBindingPattern tree) {
4606         Type type;
4607         if (tree.var.vartype != null) {
4608             type = attribType(tree.var.vartype, env);
4609         } else {
4610             type = resultInfo.pt;
4611         }
4612         tree.type = tree.var.type = type;
4613         BindingSymbol v = new BindingSymbol(tree.var.mods.flags, tree.var.name, type, env.info.scope.owner);
4614         v.pos = tree.pos;
4615         tree.var.sym = v;
4616         if (chk.checkUnique(tree.var.pos(), v, env.info.scope)) {
4617             chk.checkTransparentVar(tree.var.pos(), v, env.info.scope);
4618         }
4619         chk.validate(tree.var.vartype, env, true);
4620         if (tree.var.isImplicitlyTyped()) {
4621             setSyntheticVariableType(tree.var, type == Type.noType ? syms.errType
4622                                                                    : type);
4623         }
4624         annotate.annotateLater(tree.var.mods.annotations, env, v);
4625         if (!tree.var.isImplicitlyTyped()) {
4626             annotate.queueScanTreeAndTypeAnnotate(tree.var.vartype, env, v);
4627         }
4628         annotate.flush();
4629         result = tree.type;
4630         if (v.isUnnamedVariable()) {
4631             matchBindings = MatchBindingsComputer.EMPTY;
4632         } else {
4633             matchBindings = new MatchBindings(List.of(v), List.nil());
4634         }
4635         chk.checkRequiresIdentity(tree, env.info.lint);
4636     }
4637 
4638     @Override
4639     public void visitRecordPattern(JCRecordPattern tree) {
4640         Type site;
4641 
4642         if (tree.deconstructor == null) {
4643             log.error(tree.pos(), Errors.DeconstructionPatternVarNotAllowed);
4644             tree.record = syms.errSymbol;
4645             site = tree.type = types.createErrorType(tree.record.type);
4646         } else {
4647             Type type = attribType(tree.deconstructor, env);
4648             if (type.isRaw() && type.tsym.getTypeParameters().nonEmpty()) {
4649                 Type inferred = infer.instantiatePatternType(resultInfo.pt, type.tsym);
4650                 if (inferred == null) {
4651                     log.error(tree.pos(), Errors.PatternTypeCannotInfer);
4652                 } else {
4653                     type = inferred;
4654                 }
4655             }
4656             tree.type = tree.deconstructor.type = type;
4657             site = types.capture(tree.type);
4658         }
4659 
4660         List<Type> expectedRecordTypes;
4661         if (site.tsym.kind == Kind.TYP && ((ClassSymbol) site.tsym).isRecord()) {
4662             ClassSymbol record = (ClassSymbol) site.tsym;
4663             expectedRecordTypes = record.getRecordComponents()
4664                                         .stream()
4665                                         .map(rc -> types.memberType(site, rc))
4666                                         .map(t -> types.upward(t, types.captures(t)).baseType())
4667                                         .collect(List.collector());
4668             tree.record = record;
4669         } else {
4670             log.error(tree.pos(), Errors.DeconstructionPatternOnlyRecords(site.tsym));
4671             expectedRecordTypes = Stream.generate(() -> types.createErrorType(tree.type))
4672                                 .limit(tree.nested.size())
4673                                 .collect(List.collector());
4674             tree.record = syms.errSymbol;
4675         }
4676         ListBuffer<BindingSymbol> outBindings = new ListBuffer<>();
4677         List<Type> recordTypes = expectedRecordTypes;
4678         List<JCPattern> nestedPatterns = tree.nested;
4679         Env<AttrContext> localEnv = env.dup(tree, env.info.dup(env.info.scope.dup()));
4680         try {
4681             while (recordTypes.nonEmpty() && nestedPatterns.nonEmpty()) {
4682                 attribExpr(nestedPatterns.head, localEnv, recordTypes.head);
4683                 checkCastablePattern(nestedPatterns.head.pos(), recordTypes.head, nestedPatterns.head.type);
4684                 outBindings.addAll(matchBindings.bindingsWhenTrue);
4685                 matchBindings.bindingsWhenTrue.forEach(localEnv.info.scope::enter);
4686                 nestedPatterns = nestedPatterns.tail;
4687                 recordTypes = recordTypes.tail;
4688             }
4689             if (recordTypes.nonEmpty() || nestedPatterns.nonEmpty()) {
4690                 while (nestedPatterns.nonEmpty()) {
4691                     attribExpr(nestedPatterns.head, localEnv, Type.noType);
4692                     nestedPatterns = nestedPatterns.tail;
4693                 }
4694                 List<Type> nestedTypes =
4695                         tree.nested.stream().map(p -> p.type).collect(List.collector());
4696                 log.error(tree.pos(),
4697                           Errors.IncorrectNumberOfNestedPatterns(expectedRecordTypes,
4698                                                                  nestedTypes));
4699             }
4700         } finally {
4701             localEnv.info.scope.leave();
4702         }
4703         chk.validate(tree.deconstructor, env, true);
4704         result = tree.type;
4705         matchBindings = new MatchBindings(outBindings.toList(), List.nil());
4706     }
4707 
4708     public void visitIndexed(JCArrayAccess tree) {
4709         Type owntype = types.createErrorType(tree.type);
4710         Type atype = attribExpr(tree.indexed, env);
4711         attribExpr(tree.index, env, syms.intType);
4712         if (types.isArray(atype))
4713             owntype = types.elemtype(atype);
4714         else if (!atype.hasTag(ERROR))
4715             log.error(tree.pos(), Errors.ArrayReqButFound(atype));
4716         if (!pkind().contains(KindSelector.VAL))
4717             owntype = capture(owntype);
4718         result = check(tree, owntype, KindSelector.VAR, resultInfo);
4719     }
4720 
4721     public void visitIdent(JCIdent tree) {
4722         Symbol sym;
4723 
4724         // Find symbol
4725         if (pt().hasTag(METHOD) || pt().hasTag(FORALL)) {
4726             // If we are looking for a method, the prototype `pt' will be a
4727             // method type with the type of the call's arguments as parameters.
4728             env.info.pendingResolutionPhase = null;
4729             sym = rs.resolveMethod(tree.pos(), env, tree.name, pt().getParameterTypes(), pt().getTypeArguments());
4730         } else if (tree.sym != null && tree.sym.kind != VAR) {
4731             sym = tree.sym;
4732         } else {
4733             sym = rs.resolveIdent(tree.pos(), env, tree.name, pkind());
4734         }
4735         tree.sym = sym;
4736 
4737         // Also find the environment current for the class where
4738         // sym is defined (`symEnv').
4739         Env<AttrContext> symEnv = env;
4740         if (env.enclClass.sym.owner.kind != PCK && // we are in an inner class
4741             sym.kind.matches(KindSelector.VAL_MTH) &&
4742             sym.owner.kind == TYP &&
4743             tree.name != names._this && tree.name != names._super) {
4744 
4745             // Find environment in which identifier is defined.
4746             while (symEnv.outer != null &&
4747                    !sym.isMemberOf(symEnv.enclClass.sym, types)) {
4748                 symEnv = symEnv.outer;
4749             }
4750         }
4751 
4752         // If symbol is a variable, ...
4753         if (sym.kind == VAR) {
4754             VarSymbol v = (VarSymbol)sym;
4755 
4756             // ..., evaluate its initializer, if it has one, and check for
4757             // illegal forward reference.
4758             checkInit(tree, env, v, false);
4759 
4760             // If we are expecting a variable (as opposed to a value), check
4761             // that the variable is assignable in the current environment.
4762             if (KindSelector.ASG.subset(pkind()))
4763                 checkAssignable(tree.pos(), v, null, env);
4764         }
4765 
4766         Env<AttrContext> env1 = env;
4767         if (sym.kind != ERR && sym.kind != TYP &&
4768             sym.owner != null && sym.owner != env1.enclClass.sym) {
4769             // If the found symbol is inaccessible, then it is
4770             // accessed through an enclosing instance.  Locate this
4771             // enclosing instance:
4772             while (env1.outer != null && !rs.isAccessible(env, env1.enclClass.sym.type, sym))
4773                 env1 = env1.outer;
4774         }
4775 
4776         if (env.info.isSerializable) {
4777             chk.checkAccessFromSerializableElement(tree, env.info.isSerializableLambda);
4778         }
4779 
4780         result = checkId(tree, env1.enclClass.sym.type, sym, env, resultInfo);
4781     }
4782 
4783     public void visitSelect(JCFieldAccess tree) {
4784         // Determine the expected kind of the qualifier expression.
4785         KindSelector skind = KindSelector.NIL;
4786         if (tree.name == names._this || tree.name == names._super ||
4787                 tree.name == names._class)
4788         {
4789             skind = KindSelector.TYP;
4790         } else {
4791             if (pkind().contains(KindSelector.PCK))
4792                 skind = KindSelector.of(skind, KindSelector.PCK);
4793             if (pkind().contains(KindSelector.TYP))
4794                 skind = KindSelector.of(skind, KindSelector.TYP, KindSelector.PCK);
4795             if (pkind().contains(KindSelector.VAL_MTH))
4796                 skind = KindSelector.of(skind, KindSelector.VAL, KindSelector.TYP);
4797         }
4798 
4799         // Attribute the qualifier expression, and determine its symbol (if any).
4800         Type site = attribTree(tree.selected, env, new ResultInfo(skind, Type.noType));
4801         Assert.check(site == tree.selected.type);
4802         if (!pkind().contains(KindSelector.TYP_PCK))
4803             site = capture(site); // Capture field access
4804 
4805         // don't allow T.class T[].class, etc
4806         if (skind == KindSelector.TYP) {
4807             Type elt = site;
4808             while (elt.hasTag(ARRAY))
4809                 elt = ((ArrayType)elt).elemtype;
4810             if (elt.hasTag(TYPEVAR)) {
4811                 log.error(tree.pos(), Errors.TypeVarCantBeDeref);
4812                 result = tree.type = types.createErrorType(tree.name, site.tsym, site);
4813                 tree.sym = tree.type.tsym;
4814                 return ;
4815             }
4816         }
4817 
4818         // If qualifier symbol is a type or `super', assert `selectSuper'
4819         // for the selection. This is relevant for determining whether
4820         // protected symbols are accessible.
4821         Symbol sitesym = TreeInfo.symbol(tree.selected);
4822         boolean selectSuperPrev = env.info.selectSuper;
4823         env.info.selectSuper =
4824             sitesym != null &&
4825             sitesym.name == names._super;
4826 
4827         // Determine the symbol represented by the selection.
4828         env.info.pendingResolutionPhase = null;
4829         Symbol sym = selectSym(tree, sitesym, site, env, resultInfo);
4830         if (sym.kind == VAR && sym.name != names._super && env.info.defaultSuperCallSite != null) {
4831             log.error(tree.selected.pos(), Errors.NotEnclClass(site.tsym));
4832             sym = syms.errSymbol;
4833         }
4834         if (sym.exists() && !isType(sym) && pkind().contains(KindSelector.TYP_PCK)) {
4835             site = capture(site);
4836             sym = selectSym(tree, sitesym, site, env, resultInfo);
4837         }
4838         boolean varArgs = env.info.lastResolveVarargs();
4839         tree.sym = sym;
4840 
4841         if (site.hasTag(TYPEVAR) && !isType(sym) && sym.kind != ERR) {
4842             site = types.skipTypeVars(site, true);
4843         }
4844 
4845         // If that symbol is a variable, ...
4846         if (sym.kind == VAR) {
4847             VarSymbol v = (VarSymbol)sym;
4848 
4849             // ..., evaluate its initializer, if it has one, and check for
4850             // illegal forward reference.
4851             checkInit(tree, env, v, true);
4852 
4853             // If we are expecting a variable (as opposed to a value), check
4854             // that the variable is assignable in the current environment.
4855             if (KindSelector.ASG.subset(pkind()))
4856                 checkAssignable(tree.pos(), v, tree.selected, env);
4857         }
4858 
4859         if (sitesym != null &&
4860                 sitesym.kind == VAR &&
4861                 ((VarSymbol)sitesym).isResourceVariable() &&
4862                 sym.kind == MTH &&
4863                 sym.name.equals(names.close) &&
4864                 sym.overrides(syms.autoCloseableClose, sitesym.type.tsym, types, true)) {
4865             log.warning(tree, LintWarnings.TryExplicitCloseCall);
4866         }
4867 
4868         // Disallow selecting a type from an expression
4869         if (isType(sym) && (sitesym == null || !sitesym.kind.matches(KindSelector.TYP_PCK))) {
4870             tree.type = check(tree.selected, pt(),
4871                               sitesym == null ?
4872                                       KindSelector.VAL : sitesym.kind.toSelector(),
4873                               new ResultInfo(KindSelector.TYP_PCK, pt()));
4874         }
4875 
4876         if (isType(sitesym)) {
4877             if (sym.name != names._this && sym.name != names._super) {
4878                 // Check if type-qualified fields or methods are static (JLS)
4879                 if ((sym.flags() & STATIC) == 0 &&
4880                     sym.name != names._super &&
4881                     (sym.kind == VAR || sym.kind == MTH)) {
4882                     rs.accessBase(rs.new StaticError(sym),
4883                               tree.pos(), site, sym.name, true);
4884                 }
4885             }
4886         } else if (sym.kind != ERR &&
4887                    (sym.flags() & STATIC) != 0 &&
4888                    sym.name != names._class) {
4889             // If the qualified item is not a type and the selected item is static, report
4890             // a warning. Make allowance for the class of an array type e.g. Object[].class)
4891             if (!sym.owner.isAnonymous()) {
4892                 log.warning(tree, LintWarnings.StaticNotQualifiedByType(sym.kind.kindName(), sym.owner));
4893             } else {
4894                 log.warning(tree, LintWarnings.StaticNotQualifiedByType2(sym.kind.kindName()));
4895             }
4896         }
4897 
4898         // If we are selecting an instance member via a `super', ...
4899         if (env.info.selectSuper && (sym.flags() & STATIC) == 0) {
4900 
4901             // Check that super-qualified symbols are not abstract (JLS)
4902             rs.checkNonAbstract(tree.pos(), sym);
4903 
4904             if (site.isRaw()) {
4905                 // Determine argument types for site.
4906                 Type site1 = types.asSuper(env.enclClass.sym.type, site.tsym);
4907                 if (site1 != null) site = site1;
4908             }
4909         }
4910 
4911         if (env.info.isSerializable) {
4912             chk.checkAccessFromSerializableElement(tree, env.info.isSerializableLambda);
4913         }
4914 
4915         env.info.selectSuper = selectSuperPrev;
4916         result = checkId(tree, site, sym, env, resultInfo);
4917     }
4918     //where
4919         /** Determine symbol referenced by a Select expression,
4920          *
4921          *  @param tree   The select tree.
4922          *  @param site   The type of the selected expression,
4923          *  @param env    The current environment.
4924          *  @param resultInfo The current result.
4925          */
4926         private Symbol selectSym(JCFieldAccess tree,
4927                                  Symbol location,
4928                                  Type site,
4929                                  Env<AttrContext> env,
4930                                  ResultInfo resultInfo) {
4931             DiagnosticPosition pos = tree.pos();
4932             Name name = tree.name;
4933             switch (site.getTag()) {
4934             case PACKAGE:
4935                 return rs.accessBase(
4936                     rs.findIdentInPackage(pos, env, site.tsym, name, resultInfo.pkind),
4937                     pos, location, site, name, true);
4938             case ARRAY:
4939             case CLASS:
4940                 if (resultInfo.pt.hasTag(METHOD) || resultInfo.pt.hasTag(FORALL)) {
4941                     return rs.resolveQualifiedMethod(
4942                         pos, env, location, site, name, resultInfo.pt.getParameterTypes(), resultInfo.pt.getTypeArguments());
4943                 } else if (name == names._this || name == names._super) {
4944                     return rs.resolveSelf(pos, env, site.tsym, tree);
4945                 } else if (name == names._class) {
4946                     // In this case, we have already made sure in
4947                     // visitSelect that qualifier expression is a type.
4948                     return syms.getClassField(site, types);
4949                 } else {
4950                     // We are seeing a plain identifier as selector.
4951                     Symbol sym = rs.findIdentInType(pos, env, site, name, resultInfo.pkind);
4952                         sym = rs.accessBase(sym, pos, location, site, name, true);
4953                     return sym;
4954                 }
4955             case WILDCARD:
4956                 throw new AssertionError(tree);
4957             case TYPEVAR:
4958                 // Normally, site.getUpperBound() shouldn't be null.
4959                 // It should only happen during memberEnter/attribBase
4960                 // when determining the supertype which *must* be
4961                 // done before attributing the type variables.  In
4962                 // other words, we are seeing this illegal program:
4963                 // class B<T> extends A<T.foo> {}
4964                 Symbol sym = (site.getUpperBound() != null)
4965                     ? selectSym(tree, location, capture(site.getUpperBound()), env, resultInfo)
4966                     : null;
4967                 if (sym == null) {
4968                     log.error(pos, Errors.TypeVarCantBeDeref);
4969                     return syms.errSymbol;
4970                 } else {
4971                     // JLS 4.9 specifies the members are derived by inheritance.
4972                     // We skip inducing a whole class by filtering members that
4973                     // can never be inherited:
4974                     Symbol sym2;
4975                     if (sym.isPrivate()) {
4976                         // Private members
4977                         sym2 = rs.new AccessError(env, site, sym);
4978                     } else if (sym.owner.isInterface() && sym.kind == MTH && (sym.flags() & STATIC) != 0) {
4979                         // Interface static methods
4980                         sym2 = rs.new SymbolNotFoundError(ABSENT_MTH);
4981                     } else {
4982                         sym2 = sym;
4983                     }
4984                     rs.accessBase(sym2, pos, location, site, name, true);
4985                     return sym;
4986                 }
4987             case ERROR:
4988                 // preserve identifier names through errors
4989                 return types.createErrorType(name, site.tsym, site).tsym;
4990             default:
4991                 // The qualifier expression is of a primitive type -- only
4992                 // .class is allowed for these.
4993                 if (name == names._class) {
4994                     // In this case, we have already made sure in Select that
4995                     // qualifier expression is a type.
4996                     return syms.getClassField(site, types);
4997                 } else {
4998                     log.error(pos, Errors.CantDeref(site));
4999                     return syms.errSymbol;
5000                 }
5001             }
5002         }
5003 
5004         /** Determine type of identifier or select expression and check that
5005          *  (1) the referenced symbol is not deprecated
5006          *  (2) the symbol's type is safe (@see checkSafe)
5007          *  (3) if symbol is a variable, check that its type and kind are
5008          *      compatible with the prototype and protokind.
5009          *  (4) if symbol is an instance field of a raw type,
5010          *      which is being assigned to, issue an unchecked warning if its
5011          *      type changes under erasure.
5012          *  (5) if symbol is an instance method of a raw type, issue an
5013          *      unchecked warning if its argument types change under erasure.
5014          *  If checks succeed:
5015          *    If symbol is a constant, return its constant type
5016          *    else if symbol is a method, return its result type
5017          *    otherwise return its type.
5018          *  Otherwise return errType.
5019          *
5020          *  @param tree       The syntax tree representing the identifier
5021          *  @param site       If this is a select, the type of the selected
5022          *                    expression, otherwise the type of the current class.
5023          *  @param sym        The symbol representing the identifier.
5024          *  @param env        The current environment.
5025          *  @param resultInfo    The expected result
5026          */
5027         Type checkId(JCTree tree,
5028                      Type site,
5029                      Symbol sym,
5030                      Env<AttrContext> env,
5031                      ResultInfo resultInfo) {
5032             return (resultInfo.pt.hasTag(FORALL) || resultInfo.pt.hasTag(METHOD)) ?
5033                     checkMethodIdInternal(tree, site, sym, env, resultInfo) :
5034                     checkIdInternal(tree, site, sym, resultInfo.pt, env, resultInfo);
5035         }
5036 
5037         Type checkMethodIdInternal(JCTree tree,
5038                      Type site,
5039                      Symbol sym,
5040                      Env<AttrContext> env,
5041                      ResultInfo resultInfo) {
5042             if (resultInfo.pkind.contains(KindSelector.POLY)) {
5043                 return attrRecover.recoverMethodInvocation(tree, site, sym, env, resultInfo);
5044             } else {
5045                 return checkIdInternal(tree, site, sym, resultInfo.pt, env, resultInfo);
5046             }
5047         }
5048 
5049         Type checkIdInternal(JCTree tree,
5050                      Type site,
5051                      Symbol sym,
5052                      Type pt,
5053                      Env<AttrContext> env,
5054                      ResultInfo resultInfo) {
5055             Type owntype; // The computed type of this identifier occurrence.
5056             switch (sym.kind) {
5057             case TYP:
5058                 // For types, the computed type equals the symbol's type,
5059                 // except for two situations:
5060                 owntype = sym.type;
5061                 if (owntype.hasTag(CLASS)) {
5062                     chk.checkForBadAuxiliaryClassAccess(tree.pos(), env, (ClassSymbol)sym);
5063                     Type ownOuter = owntype.getEnclosingType();
5064 
5065                     // (a) If the symbol's type is parameterized, erase it
5066                     // because no type parameters were given.
5067                     // We recover generic outer type later in visitTypeApply.
5068                     if (owntype.tsym.type.getTypeArguments().nonEmpty()) {
5069                         owntype = types.erasure(owntype);
5070                     }
5071 
5072                     // (b) If the symbol's type is an inner class, then
5073                     // we have to interpret its outer type as a superclass
5074                     // of the site type. Example:
5075                     //
5076                     // class Tree<A> { class Visitor { ... } }
5077                     // class PointTree extends Tree<Point> { ... }
5078                     // ...PointTree.Visitor...
5079                     //
5080                     // Then the type of the last expression above is
5081                     // Tree<Point>.Visitor.
5082                     else if ((ownOuter.hasTag(CLASS) || ownOuter.hasTag(TYPEVAR)) && site != ownOuter) {
5083                         Type normOuter = types.asEnclosingSuper(site, ownOuter.tsym);
5084                         if (normOuter == null) // perhaps from an import
5085                             normOuter = types.erasure(ownOuter);
5086                         if (normOuter != ownOuter)
5087                             owntype = new ClassType(
5088                                 normOuter, List.nil(), owntype.tsym,
5089                                 owntype.getMetadata());
5090                     }
5091                 }
5092                 break;
5093             case VAR:
5094                 VarSymbol v = (VarSymbol)sym;
5095 
5096                 if (env.info.enclVar != null
5097                         && v.type.hasTag(NONE)) {
5098                     //self reference to implicitly typed variable declaration
5099                     log.error(TreeInfo.positionFor(v, env.enclClass), Errors.CantInferLocalVarType(v.name, Fragments.LocalSelfRef));
5100                     return tree.type = v.type = types.createErrorType(v.type);
5101                 }
5102 
5103                 // Test (4): if symbol is an instance field of a raw type,
5104                 // which is being assigned to, issue an unchecked warning if
5105                 // its type changes under erasure.
5106                 if (KindSelector.ASG.subset(pkind()) &&
5107                     v.owner.kind == TYP &&
5108                     (v.flags() & STATIC) == 0 &&
5109                     (site.hasTag(CLASS) || site.hasTag(TYPEVAR))) {
5110                     Type s = types.asOuterSuper(site, v.owner);
5111                     if (s != null &&
5112                         s.isRaw() &&
5113                         !types.isSameType(v.type, v.erasure(types))) {
5114                         chk.warnUnchecked(tree.pos(), LintWarnings.UncheckedAssignToVar(v, s));
5115                     }
5116                 }
5117                 // The computed type of a variable is the type of the
5118                 // variable symbol, taken as a member of the site type.
5119                 owntype = (sym.owner.kind == TYP &&
5120                            sym.name != names._this && sym.name != names._super)
5121                     ? types.memberType(site, sym)
5122                     : sym.type;
5123 
5124                 // If the variable is a constant, record constant value in
5125                 // computed type.
5126                 if (v.getConstValue() != null && isStaticReference(tree))
5127                     owntype = owntype.constType(v.getConstValue());
5128 
5129                 if (resultInfo.pkind == KindSelector.VAL) {
5130                     owntype = capture(owntype); // capture "names as expressions"
5131                 }
5132                 break;
5133             case MTH: {
5134                 owntype = checkMethod(site, sym,
5135                         new ResultInfo(resultInfo.pkind, resultInfo.pt.getReturnType(), resultInfo.checkContext, resultInfo.checkMode),
5136                         env, TreeInfo.args(env.tree), resultInfo.pt.getParameterTypes(),
5137                         resultInfo.pt.getTypeArguments());
5138                 chk.checkRestricted(tree.pos(), sym);
5139                 break;
5140             }
5141             case PCK: case ERR:
5142                 owntype = sym.type;
5143                 break;
5144             default:
5145                 throw new AssertionError("unexpected kind: " + sym.kind +
5146                                          " in tree " + tree);
5147             }
5148 
5149             // Emit a `deprecation' warning if symbol is deprecated.
5150             // (for constructors (but not for constructor references), the error
5151             // was given when the constructor was resolved)
5152 
5153             if (sym.name != names.init || tree.hasTag(REFERENCE)) {
5154                 chk.checkDeprecated(tree.pos(), env.info.scope.owner, sym);
5155                 chk.checkSunAPI(tree.pos(), sym);
5156                 chk.checkProfile(tree.pos(), sym);
5157                 chk.checkPreview(tree.pos(), env.info.scope.owner, site, sym);
5158             }
5159 
5160             if (pt.isErroneous()) {
5161                 owntype = types.createErrorType(owntype);
5162             }
5163 
5164             // If symbol is a variable, check that its type and
5165             // kind are compatible with the prototype and protokind.
5166             return check(tree, owntype, sym.kind.toSelector(), resultInfo);
5167         }
5168 
5169         /** Check that variable is initialized and evaluate the variable's
5170          *  initializer, if not yet done. Also check that variable is not
5171          *  referenced before it is defined.
5172          *  @param tree    The tree making up the variable reference.
5173          *  @param env     The current environment.
5174          *  @param v       The variable's symbol.
5175          */
5176         private void checkInit(JCTree tree,
5177                                Env<AttrContext> env,
5178                                VarSymbol v,
5179                                boolean onlyWarning) {
5180             // A forward reference is diagnosed if the declaration position
5181             // of the variable is greater than the current tree position
5182             // and the tree and variable definition occur in the same class
5183             // definition.  Note that writes don't count as references.
5184             // This check applies only to class and instance
5185             // variables.  Local variables follow different scope rules,
5186             // and are subject to definite assignment checking.
5187             Env<AttrContext> initEnv = enclosingInitEnv(env);
5188             if (initEnv != null &&
5189                 (initEnv.info.enclVar == v || v.pos > tree.pos) &&
5190                 v.owner.kind == TYP &&
5191                 v.owner == env.info.scope.owner.enclClass() &&
5192                 ((v.flags() & STATIC) != 0) == Resolve.isStatic(env) &&
5193                 (!env.tree.hasTag(ASSIGN) ||
5194                  TreeInfo.skipParens(((JCAssign) env.tree).lhs) != tree)) {
5195                 if (!onlyWarning || isStaticEnumField(v)) {
5196                     Error errkey = (initEnv.info.enclVar == v) ?
5197                                 Errors.IllegalSelfRef : Errors.IllegalForwardRef;
5198                     log.error(tree.pos(), errkey);
5199                 } else if (useBeforeDeclarationWarning) {
5200                     Warning warnkey = (initEnv.info.enclVar == v) ?
5201                                 Warnings.SelfRef(v) : Warnings.ForwardRef(v);
5202                     log.warning(tree.pos(), warnkey);
5203                 }
5204             }
5205 
5206             v.getConstValue(); // ensure initializer is evaluated
5207 
5208             checkEnumInitializer(tree, env, v);
5209         }
5210 
5211         /**
5212          * Returns the enclosing init environment associated with this env (if any). An init env
5213          * can be either a field declaration env or a static/instance initializer env.
5214          */
5215         Env<AttrContext> enclosingInitEnv(Env<AttrContext> env) {
5216             while (true) {
5217                 switch (env.tree.getTag()) {
5218                     case VARDEF:
5219                         JCVariableDecl vdecl = (JCVariableDecl)env.tree;
5220                         if (vdecl.sym.owner.kind == TYP) {
5221                             //field
5222                             return env;
5223                         }
5224                         break;
5225                     case BLOCK:
5226                         if (env.next.tree.hasTag(CLASSDEF)) {
5227                             //instance/static initializer
5228                             return env;
5229                         }
5230                         break;
5231                     case METHODDEF:
5232                     case CLASSDEF:
5233                     case TOPLEVEL:
5234                         return null;
5235                 }
5236                 Assert.checkNonNull(env.next);
5237                 env = env.next;
5238             }
5239         }
5240 
5241         /**
5242          * Check for illegal references to static members of enum.  In
5243          * an enum type, constructors and initializers may not
5244          * reference its static members unless they are constant.
5245          *
5246          * @param tree    The tree making up the variable reference.
5247          * @param env     The current environment.
5248          * @param v       The variable's symbol.
5249          * @jls 8.9 Enum Types
5250          */
5251         private void checkEnumInitializer(JCTree tree, Env<AttrContext> env, VarSymbol v) {
5252             // JLS:
5253             //
5254             // "It is a compile-time error to reference a static field
5255             // of an enum type that is not a compile-time constant
5256             // (15.28) from constructors, instance initializer blocks,
5257             // or instance variable initializer expressions of that
5258             // type. It is a compile-time error for the constructors,
5259             // instance initializer blocks, or instance variable
5260             // initializer expressions of an enum constant e to refer
5261             // to itself or to an enum constant of the same type that
5262             // is declared to the right of e."
5263             if (isStaticEnumField(v)) {
5264                 ClassSymbol enclClass = env.info.scope.owner.enclClass();
5265 
5266                 if (enclClass == null || enclClass.owner == null)
5267                     return;
5268 
5269                 // See if the enclosing class is the enum (or a
5270                 // subclass thereof) declaring v.  If not, this
5271                 // reference is OK.
5272                 if (v.owner != enclClass && !types.isSubtype(enclClass.type, v.owner.type))
5273                     return;
5274 
5275                 // If the reference isn't from an initializer, then
5276                 // the reference is OK.
5277                 if (!Resolve.isInitializer(env))
5278                     return;
5279 
5280                 log.error(tree.pos(), Errors.IllegalEnumStaticRef);
5281             }
5282         }
5283 
5284         /** Is the given symbol a static, non-constant field of an Enum?
5285          *  Note: enum literals should not be regarded as such
5286          */
5287         private boolean isStaticEnumField(VarSymbol v) {
5288             return Flags.isEnum(v.owner) &&
5289                    Flags.isStatic(v) &&
5290                    !Flags.isConstant(v) &&
5291                    v.name != names._class;
5292         }
5293 
5294     /**
5295      * Check that method arguments conform to its instantiation.
5296      **/
5297     public Type checkMethod(Type site,
5298                             final Symbol sym,
5299                             ResultInfo resultInfo,
5300                             Env<AttrContext> env,
5301                             final List<JCExpression> argtrees,
5302                             List<Type> argtypes,
5303                             List<Type> typeargtypes) {
5304         // Test (5): if symbol is an instance method of a raw type, issue
5305         // an unchecked warning if its argument types change under erasure.
5306         if ((sym.flags() & STATIC) == 0 &&
5307             (site.hasTag(CLASS) || site.hasTag(TYPEVAR))) {
5308             Type s = types.asOuterSuper(site, sym.owner);
5309             if (s != null && s.isRaw() &&
5310                 !types.isSameTypes(sym.type.getParameterTypes(),
5311                                    sym.erasure(types).getParameterTypes())) {
5312                 chk.warnUnchecked(env.tree.pos(), LintWarnings.UncheckedCallMbrOfRawType(sym, s));
5313             }
5314         }
5315 
5316         if (env.info.defaultSuperCallSite != null) {
5317             for (Type sup : types.interfaces(env.enclClass.type).prepend(types.supertype((env.enclClass.type)))) {
5318                 if (!sup.tsym.isSubClass(sym.enclClass(), types) ||
5319                         types.isSameType(sup, env.info.defaultSuperCallSite)) continue;
5320                 List<MethodSymbol> icand_sup =
5321                         types.interfaceCandidates(sup, (MethodSymbol)sym);
5322                 if (icand_sup.nonEmpty() &&
5323                         icand_sup.head != sym &&
5324                         icand_sup.head.overrides(sym, icand_sup.head.enclClass(), types, true)) {
5325                     log.error(env.tree.pos(),
5326                               Errors.IllegalDefaultSuperCall(env.info.defaultSuperCallSite, Fragments.OverriddenDefault(sym, sup)));
5327                     break;
5328                 }
5329             }
5330             env.info.defaultSuperCallSite = null;
5331         }
5332 
5333         if (sym.isStatic() && site.isInterface() && env.tree.hasTag(APPLY)) {
5334             JCMethodInvocation app = (JCMethodInvocation)env.tree;
5335             if (app.meth.hasTag(SELECT) &&
5336                     !TreeInfo.isStaticSelector(((JCFieldAccess)app.meth).selected, names)) {
5337                 log.error(env.tree.pos(), Errors.IllegalStaticIntfMethCall(site));
5338             }
5339         }
5340 
5341         // Compute the identifier's instantiated type.
5342         // For methods, we need to compute the instance type by
5343         // Resolve.instantiate from the symbol's type as well as
5344         // any type arguments and value arguments.
5345         Warner noteWarner = new Warner();
5346         try {
5347             Type owntype = rs.checkMethod(
5348                     env,
5349                     site,
5350                     sym,
5351                     resultInfo,
5352                     argtypes,
5353                     typeargtypes,
5354                     noteWarner);
5355 
5356             DeferredAttr.DeferredTypeMap<Void> checkDeferredMap =
5357                 deferredAttr.new DeferredTypeMap<>(DeferredAttr.AttrMode.CHECK, sym, env.info.pendingResolutionPhase);
5358 
5359             argtypes = argtypes.map(checkDeferredMap);
5360 
5361             if (noteWarner.hasNonSilentLint(LintCategory.UNCHECKED)) {
5362                 chk.warnUnchecked(env.tree.pos(), LintWarnings.UncheckedMethInvocationApplied(kindName(sym),
5363                         sym.name,
5364                         rs.methodArguments(sym.type.getParameterTypes()),
5365                         rs.methodArguments(argtypes.map(checkDeferredMap)),
5366                         kindName(sym.location()),
5367                         sym.location()));
5368                 if (resultInfo.pt != Infer.anyPoly ||
5369                         !owntype.hasTag(METHOD) ||
5370                         !owntype.isPartial()) {
5371                     //if this is not a partially inferred method type, erase return type. Otherwise,
5372                     //erasure is carried out in PartiallyInferredMethodType.check().
5373                     owntype = new MethodType(owntype.getParameterTypes(),
5374                             types.erasure(owntype.getReturnType()),
5375                             types.erasure(owntype.getThrownTypes()),
5376                             syms.methodClass);
5377                 }
5378             }
5379 
5380             PolyKind pkind = (sym.type.hasTag(FORALL) &&
5381                  sym.type.getReturnType().containsAny(((ForAll)sym.type).tvars)) ?
5382                  PolyKind.POLY : PolyKind.STANDALONE;
5383             TreeInfo.setPolyKind(env.tree, pkind);
5384 
5385             return (resultInfo.pt == Infer.anyPoly) ?
5386                     owntype :
5387                     chk.checkMethod(owntype, sym, env, argtrees, argtypes, env.info.lastResolveVarargs(),
5388                             resultInfo.checkContext.inferenceContext());
5389         } catch (Infer.InferenceException ex) {
5390             //invalid target type - propagate exception outwards or report error
5391             //depending on the current check context
5392             resultInfo.checkContext.report(env.tree.pos(), ex.getDiagnostic());
5393             return types.createErrorType(site);
5394         } catch (Resolve.InapplicableMethodException ex) {
5395             final JCDiagnostic diag = ex.getDiagnostic();
5396             Resolve.InapplicableSymbolError errSym = rs.new InapplicableSymbolError(null) {
5397                 @Override
5398                 protected Pair<Symbol, JCDiagnostic> errCandidate() {
5399                     return new Pair<>(sym, diag);
5400                 }
5401             };
5402             List<Type> argtypes2 = argtypes.map(
5403                     rs.new ResolveDeferredRecoveryMap(AttrMode.CHECK, sym, env.info.pendingResolutionPhase));
5404             JCDiagnostic errDiag = errSym.getDiagnostic(JCDiagnostic.DiagnosticType.ERROR,
5405                     env.tree, sym, site, sym.name, argtypes2, typeargtypes);
5406             log.report(errDiag);
5407             return types.createErrorType(site);
5408         }
5409     }
5410 
5411     public void visitLiteral(JCLiteral tree) {
5412         result = check(tree, litType(tree.typetag).constType(tree.value),
5413                 KindSelector.VAL, resultInfo);
5414     }
5415     //where
5416     /** Return the type of a literal with given type tag.
5417      */
5418     Type litType(TypeTag tag) {
5419         return (tag == CLASS) ? syms.stringType : syms.typeOfTag[tag.ordinal()];
5420     }
5421 
5422     public void visitTypeIdent(JCPrimitiveTypeTree tree) {
5423         result = check(tree, syms.typeOfTag[tree.typetag.ordinal()], KindSelector.TYP, resultInfo);
5424     }
5425 
5426     public void visitTypeArray(JCArrayTypeTree tree) {
5427         Type etype = attribType(tree.elemtype, env);
5428         Type type = new ArrayType(etype, syms.arrayClass);
5429         result = check(tree, type, KindSelector.TYP, resultInfo);
5430     }
5431 
5432     /** Visitor method for parameterized types.
5433      *  Bound checking is left until later, since types are attributed
5434      *  before supertype structure is completely known
5435      */
5436     public void visitTypeApply(JCTypeApply tree) {
5437         Type owntype = types.createErrorType(tree.type);
5438 
5439         // Attribute functor part of application and make sure it's a class.
5440         Type clazztype = chk.checkClassType(tree.clazz.pos(), attribType(tree.clazz, env));
5441 
5442         // Attribute type parameters
5443         List<Type> actuals = attribTypes(tree.arguments, env);
5444 
5445         if (clazztype.hasTag(CLASS)) {
5446             List<Type> formals = clazztype.tsym.type.getTypeArguments();
5447             if (actuals.isEmpty()) //diamond
5448                 actuals = formals;
5449 
5450             if (actuals.length() == formals.length()) {
5451                 List<Type> a = actuals;
5452                 List<Type> f = formals;
5453                 while (a.nonEmpty()) {
5454                     a.head = a.head.withTypeVar(f.head);
5455                     a = a.tail;
5456                     f = f.tail;
5457                 }
5458                 // Compute the proper generic outer
5459                 Type clazzOuter = clazztype.getEnclosingType();
5460                 if (clazzOuter.hasTag(CLASS)) {
5461                     Type site;
5462                     JCExpression clazz = TreeInfo.typeIn(tree.clazz);
5463                     if (clazz.hasTag(IDENT)) {
5464                         site = env.enclClass.sym.type;
5465                     } else if (clazz.hasTag(SELECT)) {
5466                         site = ((JCFieldAccess) clazz).selected.type;
5467                     } else throw new AssertionError(""+tree);
5468                     if (clazzOuter.hasTag(CLASS) && site != clazzOuter) {
5469                         if (site.hasTag(CLASS) || site.hasTag(TYPEVAR))
5470                             site = types.asEnclosingSuper(site, clazzOuter.tsym);
5471                         if (site == null)
5472                             site = types.erasure(clazzOuter);
5473                         clazzOuter = site;
5474                     }
5475                 }
5476                 owntype = new ClassType(clazzOuter, actuals, clazztype.tsym,
5477                                         clazztype.getMetadata());
5478             } else {
5479                 if (formals.length() != 0) {
5480                     log.error(tree.pos(),
5481                               Errors.WrongNumberTypeArgs(Integer.toString(formals.length())));
5482                 } else {
5483                     log.error(tree.pos(), Errors.TypeDoesntTakeParams(clazztype.tsym));
5484                 }
5485                 owntype = types.createErrorType(tree.type);
5486             }
5487         } else if (clazztype.hasTag(ERROR)) {
5488             ErrorType parameterizedErroneous =
5489                     new ErrorType(clazztype.getOriginalType(),
5490                                   clazztype.tsym,
5491                                   clazztype.getMetadata());
5492 
5493             parameterizedErroneous.typarams_field = actuals;
5494             owntype = parameterizedErroneous;
5495         }
5496         result = check(tree, owntype, KindSelector.TYP, resultInfo);
5497     }
5498 
5499     public void visitTypeUnion(JCTypeUnion tree) {
5500         ListBuffer<Type> multicatchTypes = new ListBuffer<>();
5501         ListBuffer<Type> all_multicatchTypes = null; // lazy, only if needed
5502         for (JCExpression typeTree : tree.alternatives) {
5503             Type ctype = attribType(typeTree, env);
5504             ctype = chk.checkType(typeTree.pos(),
5505                           chk.checkClassType(typeTree.pos(), ctype),
5506                           syms.throwableType);
5507             if (!ctype.isErroneous()) {
5508                 //check that alternatives of a union type are pairwise
5509                 //unrelated w.r.t. subtyping
5510                 if (chk.intersects(ctype,  multicatchTypes.toList())) {
5511                     for (Type t : multicatchTypes) {
5512                         boolean sub = types.isSubtype(ctype, t);
5513                         boolean sup = types.isSubtype(t, ctype);
5514                         if (sub || sup) {
5515                             //assume 'a' <: 'b'
5516                             Type a = sub ? ctype : t;
5517                             Type b = sub ? t : ctype;
5518                             log.error(typeTree.pos(), Errors.MulticatchTypesMustBeDisjoint(a, b));
5519                         }
5520                     }
5521                 }
5522                 multicatchTypes.append(ctype);
5523                 if (all_multicatchTypes != null)
5524                     all_multicatchTypes.append(ctype);
5525             } else {
5526                 if (all_multicatchTypes == null) {
5527                     all_multicatchTypes = new ListBuffer<>();
5528                     all_multicatchTypes.appendList(multicatchTypes);
5529                 }
5530                 all_multicatchTypes.append(ctype);
5531             }
5532         }
5533         Type t = check(tree, types.lub(multicatchTypes.toList()),
5534                 KindSelector.TYP, resultInfo.dup(CheckMode.NO_TREE_UPDATE));
5535         if (t.hasTag(CLASS)) {
5536             List<Type> alternatives =
5537                 ((all_multicatchTypes == null) ? multicatchTypes : all_multicatchTypes).toList();
5538             t = new UnionClassType((ClassType) t, alternatives);
5539         }
5540         tree.type = result = t;
5541     }
5542 
5543     public void visitTypeIntersection(JCTypeIntersection tree) {
5544         attribTypes(tree.bounds, env);
5545         tree.type = result = checkIntersection(tree, tree.bounds);
5546     }
5547 
5548     public void visitTypeParameter(JCTypeParameter tree) {
5549         TypeVar typeVar = (TypeVar) tree.type;
5550 
5551         if (tree.annotations != null && tree.annotations.nonEmpty()) {
5552             annotate.annotateTypeParameterSecondStage(tree, tree.annotations);
5553         }
5554 
5555         if (!typeVar.getUpperBound().isErroneous()) {
5556             //fixup type-parameter bound computed in 'attribTypeVariables'
5557             typeVar.setUpperBound(checkIntersection(tree, tree.bounds));
5558         }
5559     }
5560 
5561     Type checkIntersection(JCTree tree, List<JCExpression> bounds) {
5562         Set<Symbol> boundSet = new HashSet<>();
5563         if (bounds.nonEmpty()) {
5564             // accept class or interface or typevar as first bound.
5565             bounds.head.type = checkBase(bounds.head.type, bounds.head, env, false, false, false);
5566             boundSet.add(types.erasure(bounds.head.type).tsym);
5567             if (bounds.head.type.isErroneous()) {
5568                 return bounds.head.type;
5569             }
5570             else if (bounds.head.type.hasTag(TYPEVAR)) {
5571                 // if first bound was a typevar, do not accept further bounds.
5572                 if (bounds.tail.nonEmpty()) {
5573                     log.error(bounds.tail.head.pos(),
5574                               Errors.TypeVarMayNotBeFollowedByOtherBounds);
5575                     return bounds.head.type;
5576                 }
5577             } else {
5578                 // if first bound was a class or interface, accept only interfaces
5579                 // as further bounds.
5580                 for (JCExpression bound : bounds.tail) {
5581                     bound.type = checkBase(bound.type, bound, env, false, true, false);
5582                     if (bound.type.isErroneous()) {
5583                         bounds = List.of(bound);
5584                     }
5585                     else if (bound.type.hasTag(CLASS)) {
5586                         chk.checkNotRepeated(bound.pos(), types.erasure(bound.type), boundSet);
5587                     }
5588                 }
5589             }
5590         }
5591 
5592         if (bounds.length() == 0) {
5593             return syms.objectType;
5594         } else if (bounds.length() == 1) {
5595             return bounds.head.type;
5596         } else {
5597             Type owntype = types.makeIntersectionType(TreeInfo.types(bounds));
5598             // ... the variable's bound is a class type flagged COMPOUND
5599             // (see comment for TypeVar.bound).
5600             // In this case, generate a class tree that represents the
5601             // bound class, ...
5602             JCExpression extending;
5603             List<JCExpression> implementing;
5604             if (!bounds.head.type.isInterface()) {
5605                 extending = bounds.head;
5606                 implementing = bounds.tail;
5607             } else {
5608                 extending = null;
5609                 implementing = bounds;
5610             }
5611             JCClassDecl cd = make.at(tree).ClassDef(
5612                 make.Modifiers(PUBLIC | ABSTRACT),
5613                 names.empty, List.nil(),
5614                 extending, implementing, List.nil());
5615 
5616             ClassSymbol c = (ClassSymbol)owntype.tsym;
5617             Assert.check((c.flags() & COMPOUND) != 0);
5618             cd.sym = c;
5619             c.sourcefile = env.toplevel.sourcefile;
5620 
5621             // ... and attribute the bound class
5622             c.flags_field |= UNATTRIBUTED;
5623             Env<AttrContext> cenv = enter.classEnv(cd, env);
5624             typeEnvs.put(c, cenv);
5625             attribClass(c);
5626             return owntype;
5627         }
5628     }
5629 
5630     public void visitWildcard(JCWildcard tree) {
5631         //- System.err.println("visitWildcard("+tree+");");//DEBUG
5632         Type type = (tree.kind.kind == BoundKind.UNBOUND)
5633             ? syms.objectType
5634             : attribType(tree.inner, env);
5635         result = check(tree, new WildcardType(chk.checkRefType(tree.pos(), type),
5636                                               tree.kind.kind,
5637                                               syms.boundClass),
5638                 KindSelector.TYP, resultInfo);
5639     }
5640 
5641     public void visitAnnotation(JCAnnotation tree) {
5642         Assert.error("should be handled in annotate");
5643     }
5644 
5645     @Override
5646     public void visitModifiers(JCModifiers tree) {
5647         //error recovery only:
5648         Assert.check(resultInfo.pkind == KindSelector.ERR);
5649 
5650         attribAnnotationTypes(tree.annotations, env);
5651     }
5652 
5653     public void visitAnnotatedType(JCAnnotatedType tree) {
5654         attribAnnotationTypes(tree.annotations, env);
5655         Type underlyingType = attribType(tree.underlyingType, env);
5656         Type annotatedType = underlyingType.preannotatedType();
5657 
5658         annotate.annotateTypeSecondStage(tree, tree.annotations, annotatedType);
5659         result = tree.type = annotatedType;
5660     }
5661 
5662     public void visitErroneous(JCErroneous tree) {
5663         if (tree.errs != null) {
5664             WriteableScope newScope = env.info.scope;
5665 
5666             if (env.tree instanceof JCClassDecl) {
5667                 Symbol fakeOwner =
5668                     new MethodSymbol(BLOCK, names.empty, null,
5669                         env.info.scope.owner);
5670                 newScope = newScope.dupUnshared(fakeOwner);
5671             }
5672 
5673             Env<AttrContext> errEnv =
5674                     env.dup(env.tree,
5675                             env.info.dup(newScope));
5676             errEnv.info.returnResult = unknownExprInfo;
5677             for (JCTree err : tree.errs)
5678                 attribTree(err, errEnv, new ResultInfo(KindSelector.ERR, pt()));
5679         }
5680         result = tree.type = syms.errType;
5681     }
5682 
5683     /** Default visitor method for all other trees.
5684      */
5685     public void visitTree(JCTree tree) {
5686         throw new AssertionError();
5687     }
5688 
5689     /**
5690      * Attribute an env for either a top level tree or class or module declaration.
5691      */
5692     public void attrib(Env<AttrContext> env) {
5693         switch (env.tree.getTag()) {
5694             case MODULEDEF:
5695                 attribModule(env.tree.pos(), ((JCModuleDecl)env.tree).sym);
5696                 break;
5697             case PACKAGEDEF:
5698                 attribPackage(env.tree.pos(), ((JCPackageDecl) env.tree).packge);
5699                 break;
5700             default:
5701                 attribClass(env.tree.pos(), env.enclClass.sym);
5702         }
5703 
5704         annotate.flush();
5705 
5706         // Now that this tree is attributed, we can calculate the Lint configuration everywhere within it
5707         lintMapper.calculateLints(env.toplevel.sourcefile, env.tree, env.toplevel.endPositions);
5708     }
5709 
5710     public void attribPackage(DiagnosticPosition pos, PackageSymbol p) {
5711         try {
5712             annotate.flush();
5713             attribPackage(p);
5714         } catch (CompletionFailure ex) {
5715             chk.completionError(pos, ex);
5716         }
5717     }
5718 
5719     void attribPackage(PackageSymbol p) {
5720         attribWithLint(p,
5721                        env -> chk.checkDeprecatedAnnotation(((JCPackageDecl) env.tree).pid.pos(), p));
5722     }
5723 
5724     public void attribModule(DiagnosticPosition pos, ModuleSymbol m) {
5725         try {
5726             annotate.flush();
5727             attribModule(m);
5728         } catch (CompletionFailure ex) {
5729             chk.completionError(pos, ex);
5730         }
5731     }
5732 
5733     void attribModule(ModuleSymbol m) {
5734         attribWithLint(m, env -> attribStat(env.tree, env));
5735     }
5736 
5737     private void attribWithLint(TypeSymbol sym, Consumer<Env<AttrContext>> attrib) {
5738         Env<AttrContext> env = typeEnvs.get(sym);
5739 
5740         Env<AttrContext> lintEnv = env;
5741         while (lintEnv.info.lint == null)
5742             lintEnv = lintEnv.next;
5743 
5744         Lint lint = lintEnv.info.lint.augment(sym);
5745 
5746         Lint prevLint = chk.setLint(lint);
5747         JavaFileObject prev = log.useSource(env.toplevel.sourcefile);
5748 
5749         try {
5750             attrib.accept(env);
5751         } finally {
5752             log.useSource(prev);
5753             chk.setLint(prevLint);
5754         }
5755     }
5756 
5757     /** Main method: attribute class definition associated with given class symbol.
5758      *  reporting completion failures at the given position.
5759      *  @param pos The source position at which completion errors are to be
5760      *             reported.
5761      *  @param c   The class symbol whose definition will be attributed.
5762      */
5763     public void attribClass(DiagnosticPosition pos, ClassSymbol c) {
5764         try {
5765             annotate.flush();
5766             attribClass(c);
5767         } catch (CompletionFailure ex) {
5768             chk.completionError(pos, ex);
5769         }
5770     }
5771 
5772     /** Attribute class definition associated with given class symbol.
5773      *  @param c   The class symbol whose definition will be attributed.
5774      */
5775     void attribClass(ClassSymbol c) throws CompletionFailure {
5776         if (c.type.hasTag(ERROR)) return;
5777 
5778         // Check for cycles in the inheritance graph, which can arise from
5779         // ill-formed class files.
5780         chk.checkNonCyclic(null, c.type);
5781 
5782         Type st = types.supertype(c.type);
5783         if ((c.flags_field & Flags.COMPOUND) == 0 &&
5784             (c.flags_field & Flags.SUPER_OWNER_ATTRIBUTED) == 0) {
5785             // First, attribute superclass.
5786             if (st.hasTag(CLASS))
5787                 attribClass((ClassSymbol)st.tsym);
5788 
5789             // Next attribute owner, if it is a class.
5790             if (c.owner.kind == TYP && c.owner.type.hasTag(CLASS))
5791                 attribClass((ClassSymbol)c.owner);
5792 
5793             c.flags_field |= Flags.SUPER_OWNER_ATTRIBUTED;
5794         }
5795 
5796         // The previous operations might have attributed the current class
5797         // if there was a cycle. So we test first whether the class is still
5798         // UNATTRIBUTED.
5799         if ((c.flags_field & UNATTRIBUTED) != 0) {
5800             c.flags_field &= ~UNATTRIBUTED;
5801 
5802             // Get environment current at the point of class definition.
5803             Env<AttrContext> env = typeEnvs.get(c);
5804 
5805             // The info.lint field in the envs stored in typeEnvs is deliberately uninitialized,
5806             // because the annotations were not available at the time the env was created. Therefore,
5807             // we look up the environment chain for the first enclosing environment for which the
5808             // lint value is set. Typically, this is the parent env, but might be further if there
5809             // are any envs created as a result of TypeParameter nodes.
5810             Env<AttrContext> lintEnv = env;
5811             while (lintEnv.info.lint == null)
5812                 lintEnv = lintEnv.next;
5813 
5814             // Having found the enclosing lint value, we can initialize the lint value for this class
5815             env.info.lint = lintEnv.info.lint.augment(c);
5816 
5817             Lint prevLint = chk.setLint(env.info.lint);
5818             JavaFileObject prev = log.useSource(c.sourcefile);
5819             ResultInfo prevReturnRes = env.info.returnResult;
5820 
5821             try {
5822                 if (c.isSealed() &&
5823                         !c.isEnum() &&
5824                         !c.isPermittedExplicit &&
5825                         c.getPermittedSubclasses().isEmpty()) {
5826                     log.error(TreeInfo.diagnosticPositionFor(c, env.tree), Errors.SealedClassMustHaveSubclasses);
5827                 }
5828 
5829                 if (c.isSealed()) {
5830                     Set<Symbol> permittedTypes = new HashSet<>();
5831                     boolean sealedInUnnamed = c.packge().modle == syms.unnamedModule || c.packge().modle == syms.noModule;
5832                     for (Type subType : c.getPermittedSubclasses()) {
5833                         if (subType.isErroneous()) {
5834                             // the type already caused errors, don't produce more potentially misleading errors
5835                             continue;
5836                         }
5837                         boolean isTypeVar = false;
5838                         if (subType.getTag() == TYPEVAR) {
5839                             isTypeVar = true; //error recovery
5840                             log.error(TreeInfo.diagnosticPositionFor(subType.tsym, env.tree),
5841                                     Errors.InvalidPermitsClause(Fragments.IsATypeVariable(subType)));
5842                         }
5843                         if (subType.tsym.isAnonymous() && !c.isEnum()) {
5844                             log.error(TreeInfo.diagnosticPositionFor(subType.tsym, env.tree),  Errors.LocalClassesCantExtendSealed(Fragments.Anonymous));
5845                         }
5846                         if (permittedTypes.contains(subType.tsym)) {
5847                             DiagnosticPosition pos =
5848                                     env.enclClass.permitting.stream()
5849                                             .filter(permittedExpr -> TreeInfo.diagnosticPositionFor(subType.tsym, permittedExpr, true) != null)
5850                                             .limit(2).collect(List.collector()).get(1);
5851                             log.error(pos, Errors.InvalidPermitsClause(Fragments.IsDuplicated(subType)));
5852                         } else {
5853                             permittedTypes.add(subType.tsym);
5854                         }
5855                         if (sealedInUnnamed) {
5856                             if (subType.tsym.packge() != c.packge()) {
5857                                 log.error(TreeInfo.diagnosticPositionFor(subType.tsym, env.tree),
5858                                         Errors.ClassInUnnamedModuleCantExtendSealedInDiffPackage(c)
5859                                 );
5860                             }
5861                         } else if (subType.tsym.packge().modle != c.packge().modle) {
5862                             log.error(TreeInfo.diagnosticPositionFor(subType.tsym, env.tree),
5863                                     Errors.ClassInModuleCantExtendSealedInDiffModule(c, c.packge().modle)
5864                             );
5865                         }
5866                         if (subType.tsym == c.type.tsym || types.isSuperType(subType, c.type)) {
5867                             log.error(TreeInfo.diagnosticPositionFor(subType.tsym, ((JCClassDecl)env.tree).permitting),
5868                                     Errors.InvalidPermitsClause(
5869                                             subType.tsym == c.type.tsym ?
5870                                                     Fragments.MustNotBeSameClass :
5871                                                     Fragments.MustNotBeSupertype(subType)
5872                                     )
5873                             );
5874                         } else if (!isTypeVar) {
5875                             boolean thisIsASuper = types.directSupertypes(subType)
5876                                                         .stream()
5877                                                         .anyMatch(d -> d.tsym == c);
5878                             if (!thisIsASuper) {
5879                                 if(c.isInterface()) {
5880                                     log.error(TreeInfo.diagnosticPositionFor(subType.tsym, env.tree),
5881                                             Errors.InvalidPermitsClause(Fragments.DoesntImplementSealed(kindName(subType.tsym), subType)));
5882                                 } else {
5883                                     log.error(TreeInfo.diagnosticPositionFor(subType.tsym, env.tree),
5884                                             Errors.InvalidPermitsClause(Fragments.DoesntExtendSealed(subType)));
5885                                 }
5886                             }
5887                         }
5888                     }
5889                 }
5890 
5891                 List<ClassSymbol> sealedSupers = types.directSupertypes(c.type)
5892                                                       .stream()
5893                                                       .filter(s -> s.tsym.isSealed())
5894                                                       .map(s -> (ClassSymbol) s.tsym)
5895                                                       .collect(List.collector());
5896 
5897                 if (sealedSupers.isEmpty()) {
5898                     if ((c.flags_field & Flags.NON_SEALED) != 0) {
5899                         boolean hasErrorSuper = false;
5900 
5901                         hasErrorSuper |= types.directSupertypes(c.type)
5902                                               .stream()
5903                                               .anyMatch(s -> s.tsym.kind == Kind.ERR);
5904 
5905                         ClassType ct = (ClassType) c.type;
5906 
5907                         hasErrorSuper |= !ct.isCompound() && ct.interfaces_field != ct.all_interfaces_field;
5908 
5909                         if (!hasErrorSuper) {
5910                             log.error(TreeInfo.diagnosticPositionFor(c, env.tree), Errors.NonSealedWithNoSealedSupertype(c));
5911                         }
5912                     }
5913                 } else if ((c.flags_field & Flags.COMPOUND) == 0) {
5914                     if (c.isDirectlyOrIndirectlyLocal() && !c.isEnum()) {
5915                         log.error(TreeInfo.diagnosticPositionFor(c, env.tree), Errors.LocalClassesCantExtendSealed(c.isAnonymous() ? Fragments.Anonymous : Fragments.Local));
5916                     }
5917 
5918                     if (!c.type.isCompound()) {
5919                         for (ClassSymbol supertypeSym : sealedSupers) {
5920                             if (!supertypeSym.isPermittedSubclass(c.type.tsym)) {
5921                                 log.error(TreeInfo.diagnosticPositionFor(c.type.tsym, env.tree), Errors.CantInheritFromSealed(supertypeSym));
5922                             }
5923                         }
5924                         if (!c.isNonSealed() && !c.isFinal() && !c.isSealed()) {
5925                             log.error(TreeInfo.diagnosticPositionFor(c, env.tree),
5926                                     c.isInterface() ?
5927                                             Errors.NonSealedOrSealedExpected :
5928                                             Errors.NonSealedSealedOrFinalExpected);
5929                         }
5930                     }
5931                 }
5932 
5933                 env.info.returnResult = null;
5934                 // java.lang.Enum may not be subclassed by a non-enum
5935                 if (st.tsym == syms.enumSym &&
5936                     ((c.flags_field & (Flags.ENUM|Flags.COMPOUND)) == 0))
5937                     log.error(env.tree.pos(), Errors.EnumNoSubclassing);
5938 
5939                 // Enums may not be extended by source-level classes
5940                 if (st.tsym != null &&
5941                     ((st.tsym.flags_field & Flags.ENUM) != 0) &&
5942                     ((c.flags_field & (Flags.ENUM | Flags.COMPOUND)) == 0)) {
5943                     log.error(env.tree.pos(), Errors.EnumTypesNotExtensible);
5944                 }
5945 
5946                 if (rs.isSerializable(c.type)) {
5947                     env.info.isSerializable = true;
5948                 }
5949 
5950                 if (c.isValueClass()) {
5951                     Assert.check(env.tree.hasTag(CLASSDEF));
5952                     chk.checkConstraintsOfValueClass((JCClassDecl) env.tree, c);
5953                 }
5954 
5955                 attribClassBody(env, c);
5956 
5957                 chk.checkDeprecatedAnnotation(env.tree.pos(), c);
5958                 chk.checkClassOverrideEqualsAndHashIfNeeded(env.tree.pos(), c);
5959                 chk.checkFunctionalInterface((JCClassDecl) env.tree, c);
5960                 chk.checkLeaksNotAccessible(env, (JCClassDecl) env.tree);
5961 
5962                 if (c.isImplicit()) {
5963                     chk.checkHasMain(env.tree.pos(), c);
5964                 }
5965             } finally {
5966                 env.info.returnResult = prevReturnRes;
5967                 log.useSource(prev);
5968                 chk.setLint(prevLint);
5969             }
5970 
5971         }
5972     }
5973 
5974     public void visitImport(JCImport tree) {
5975         // nothing to do
5976     }
5977 
5978     public void visitModuleDef(JCModuleDecl tree) {
5979         tree.sym.completeUsesProvides();
5980         ModuleSymbol msym = tree.sym;
5981         Lint lint = env.outer.info.lint = env.outer.info.lint.augment(msym);
5982         Lint prevLint = chk.setLint(lint);
5983         try {
5984             chk.checkModuleName(tree);
5985             chk.checkDeprecatedAnnotation(tree, msym);
5986         } finally {
5987             chk.setLint(prevLint);
5988         }
5989     }
5990 
5991     /** Finish the attribution of a class. */
5992     private void attribClassBody(Env<AttrContext> env, ClassSymbol c) {
5993         JCClassDecl tree = (JCClassDecl)env.tree;
5994         Assert.check(c == tree.sym);
5995 
5996         // Validate type parameters, supertype and interfaces.
5997         attribStats(tree.typarams, env);
5998         if (!c.isAnonymous()) {
5999             //already checked if anonymous
6000             chk.validate(tree.typarams, env);
6001             chk.validate(tree.extending, env);
6002             chk.validate(tree.implementing, env);
6003         }
6004 
6005         chk.checkRequiresIdentity(tree, env.info.lint);
6006 
6007         c.markAbstractIfNeeded(types);
6008 
6009         // If this is a non-abstract class, check that it has no abstract
6010         // methods or unimplemented methods of an implemented interface.
6011         if ((c.flags() & (ABSTRACT | INTERFACE)) == 0) {
6012             chk.checkAllDefined(tree.pos(), c);
6013         }
6014 
6015         if ((c.flags() & ANNOTATION) != 0) {
6016             if (tree.implementing.nonEmpty())
6017                 log.error(tree.implementing.head.pos(),
6018                           Errors.CantExtendIntfAnnotation);
6019             if (tree.typarams.nonEmpty()) {
6020                 log.error(tree.typarams.head.pos(),
6021                           Errors.IntfAnnotationCantHaveTypeParams(c));
6022             }
6023 
6024             // If this annotation type has a @Repeatable, validate
6025             Attribute.Compound repeatable = c.getAnnotationTypeMetadata().getRepeatable();
6026             // If this annotation type has a @Repeatable, validate
6027             if (repeatable != null) {
6028                 // get diagnostic position for error reporting
6029                 DiagnosticPosition cbPos = getDiagnosticPosition(tree, repeatable.type);
6030                 Assert.checkNonNull(cbPos);
6031 
6032                 chk.validateRepeatable(c, repeatable, cbPos);
6033             }
6034         } else {
6035             try {
6036                 // Check that all extended classes and interfaces
6037                 // are compatible (i.e. no two define methods with same arguments
6038                 // yet different return types).  (JLS 8.4.8.3)
6039                 chk.checkCompatibleSupertypes(tree.pos(), c.type);
6040                 chk.checkDefaultMethodClashes(tree.pos(), c.type);
6041                 chk.checkPotentiallyAmbiguousOverloads(tree, c.type);
6042             } catch (CompletionFailure cf) {
6043                 chk.completionError(tree.pos(), cf);
6044             }
6045         }
6046 
6047         // Check that class does not import the same parameterized interface
6048         // with two different argument lists.
6049         chk.checkClassBounds(tree.pos(), c.type);
6050 
6051         tree.type = c.type;
6052 
6053         for (List<JCTypeParameter> l = tree.typarams;
6054              l.nonEmpty(); l = l.tail) {
6055              Assert.checkNonNull(env.info.scope.findFirst(l.head.name));
6056         }
6057 
6058         // Check that a generic class doesn't extend Throwable
6059         if (!c.type.allparams().isEmpty() && types.isSubtype(c.type, syms.throwableType))
6060             log.error(tree.extending.pos(), Errors.GenericThrowable);
6061 
6062         // Check that all methods which implement some
6063         // method conform to the method they implement.
6064         chk.checkImplementations(tree);
6065 
6066         //check that a resource implementing AutoCloseable cannot throw InterruptedException
6067         checkAutoCloseable(env, tree, false);
6068 
6069         for (List<JCTree> l = tree.defs; l.nonEmpty(); l = l.tail) {
6070             // Attribute declaration
6071             attribStat(l.head, env);
6072             // Check that declarations in inner classes are not static (JLS 8.1.2)
6073             // Make an exception for static constants.
6074             if (!allowRecords &&
6075                     c.owner.kind != PCK &&
6076                     ((c.flags() & STATIC) == 0 || c.name == names.empty) &&
6077                     (TreeInfo.flags(l.head) & (STATIC | INTERFACE)) != 0) {
6078                 VarSymbol sym = null;
6079                 if (l.head.hasTag(VARDEF)) sym = ((JCVariableDecl) l.head).sym;
6080                 if (sym == null ||
6081                         sym.kind != VAR ||
6082                         sym.getConstValue() == null)
6083                     log.error(l.head.pos(), Errors.IclsCantHaveStaticDecl(c));
6084             }
6085         }
6086 
6087         // Check for proper placement of super()/this() calls.
6088         chk.checkSuperInitCalls(tree);
6089 
6090         // Check for cycles among non-initial constructors.
6091         chk.checkCyclicConstructors(tree);
6092 
6093         // Check for cycles among annotation elements.
6094         chk.checkNonCyclicElements(tree);
6095 
6096         // Check for proper use of serialVersionUID and other
6097         // serialization-related fields and methods
6098         if (env.info.lint.isEnabled(LintCategory.SERIAL)
6099                 && rs.isSerializable(c.type)
6100                 && !c.isAnonymous()) {
6101             chk.checkSerialStructure(env, tree, c);
6102         }
6103         // Correctly organize the positions of the type annotations
6104         typeAnnotations.organizeTypeAnnotationsBodies(tree);
6105 
6106         // Check type annotations applicability rules
6107         validateTypeAnnotations(tree, false);
6108     }
6109         // where
6110         /** get a diagnostic position for an attribute of Type t, or null if attribute missing */
6111         private DiagnosticPosition getDiagnosticPosition(JCClassDecl tree, Type t) {
6112             for(List<JCAnnotation> al = tree.mods.annotations; !al.isEmpty(); al = al.tail) {
6113                 if (types.isSameType(al.head.annotationType.type, t))
6114                     return al.head.pos();
6115             }
6116 
6117             return null;
6118         }
6119 
6120     private Type capture(Type type) {
6121         return types.capture(type);
6122     }
6123 
6124     private void setSyntheticVariableType(JCVariableDecl tree, Type type) {
6125         if (type.isErroneous()) {
6126             tree.vartype = make.at(tree.pos()).Erroneous();
6127         } else if (tree.declaredUsingVar()) {
6128             Assert.check(tree.typePos != Position.NOPOS);
6129             tree.vartype = make.at(tree.typePos).Type(type);
6130         } else {
6131             tree.vartype = make.at(tree.pos()).Type(type);
6132         }
6133     }
6134 
6135     public void validateTypeAnnotations(JCTree tree, boolean sigOnly) {
6136         tree.accept(new TypeAnnotationsValidator(sigOnly));
6137     }
6138     //where
6139     private final class TypeAnnotationsValidator extends TreeScanner {
6140 
6141         private final boolean sigOnly;
6142         public TypeAnnotationsValidator(boolean sigOnly) {
6143             this.sigOnly = sigOnly;
6144         }
6145 
6146         public void visitAnnotation(JCAnnotation tree) {
6147             chk.validateTypeAnnotation(tree, null, false);
6148             super.visitAnnotation(tree);
6149         }
6150         public void visitAnnotatedType(JCAnnotatedType tree) {
6151             if (!tree.underlyingType.type.isErroneous()) {
6152                 super.visitAnnotatedType(tree);
6153             }
6154         }
6155         public void visitTypeParameter(JCTypeParameter tree) {
6156             chk.validateTypeAnnotations(tree.annotations, tree.type.tsym, true);
6157             scan(tree.bounds);
6158             // Don't call super.
6159             // This is needed because above we call validateTypeAnnotation with
6160             // false, which would forbid annotations on type parameters.
6161             // super.visitTypeParameter(tree);
6162         }
6163         public void visitMethodDef(JCMethodDecl tree) {
6164             if (tree.recvparam != null &&
6165                     !tree.recvparam.vartype.type.isErroneous()) {
6166                 checkForDeclarationAnnotations(tree.recvparam.mods.annotations, tree.recvparam.sym);
6167             }
6168             if (tree.restype != null && tree.restype.type != null) {
6169                 validateAnnotatedType(tree.restype, tree.restype.type);
6170             }
6171             if (sigOnly) {
6172                 scan(tree.mods);
6173                 scan(tree.restype);
6174                 scan(tree.typarams);
6175                 scan(tree.recvparam);
6176                 scan(tree.params);
6177                 scan(tree.thrown);
6178             } else {
6179                 scan(tree.defaultValue);
6180                 scan(tree.body);
6181             }
6182         }
6183         public void visitVarDef(final JCVariableDecl tree) {
6184             //System.err.println("validateTypeAnnotations.visitVarDef " + tree);
6185             if (tree.sym != null && tree.sym.type != null && !tree.isImplicitlyTyped())
6186                 validateAnnotatedType(tree.vartype, tree.sym.type);
6187             scan(tree.mods);
6188             scan(tree.vartype);
6189             if (!sigOnly) {
6190                 scan(tree.init);
6191             }
6192         }
6193         public void visitTypeCast(JCTypeCast tree) {
6194             if (tree.clazz != null && tree.clazz.type != null)
6195                 validateAnnotatedType(tree.clazz, tree.clazz.type);
6196             super.visitTypeCast(tree);
6197         }
6198         public void visitTypeTest(JCInstanceOf tree) {
6199             if (tree.pattern != null && !(tree.pattern instanceof JCPattern) && tree.pattern.type != null)
6200                 validateAnnotatedType(tree.pattern, tree.pattern.type);
6201             super.visitTypeTest(tree);
6202         }
6203         public void visitNewClass(JCNewClass tree) {
6204             if (tree.clazz != null && tree.clazz.type != null) {
6205                 if (tree.clazz.hasTag(ANNOTATED_TYPE)) {
6206                     checkForDeclarationAnnotations(((JCAnnotatedType) tree.clazz).annotations,
6207                             tree.clazz.type.tsym);
6208                 }
6209                 if (tree.def != null) {
6210                     checkForDeclarationAnnotations(tree.def.mods.annotations, tree.clazz.type.tsym);
6211                 }
6212 
6213                 validateAnnotatedType(tree.clazz, tree.clazz.type);
6214             }
6215             super.visitNewClass(tree);
6216         }
6217         public void visitNewArray(JCNewArray tree) {
6218             if (tree.elemtype != null && tree.elemtype.type != null) {
6219                 if (tree.elemtype.hasTag(ANNOTATED_TYPE)) {
6220                     checkForDeclarationAnnotations(((JCAnnotatedType) tree.elemtype).annotations,
6221                             tree.elemtype.type.tsym);
6222                 }
6223                 validateAnnotatedType(tree.elemtype, tree.elemtype.type);
6224             }
6225             super.visitNewArray(tree);
6226         }
6227         public void visitClassDef(JCClassDecl tree) {
6228             //System.err.println("validateTypeAnnotations.visitClassDef " + tree);
6229             if (sigOnly) {
6230                 scan(tree.mods);
6231                 scan(tree.typarams);
6232                 scan(tree.extending);
6233                 scan(tree.implementing);
6234             }
6235             for (JCTree member : tree.defs) {
6236                 if (member.hasTag(Tag.CLASSDEF)) {
6237                     continue;
6238                 }
6239                 scan(member);
6240             }
6241         }
6242         public void visitBlock(JCBlock tree) {
6243             if (!sigOnly) {
6244                 scan(tree.stats);
6245             }
6246         }
6247 
6248         /* I would want to model this after
6249          * com.sun.tools.javac.comp.Check.Validator.visitSelectInternal(JCFieldAccess)
6250          * and override visitSelect and visitTypeApply.
6251          * However, we only set the annotated type in the top-level type
6252          * of the symbol.
6253          * Therefore, we need to override each individual location where a type
6254          * can occur.
6255          */
6256         private void validateAnnotatedType(final JCTree errtree, final Type type) {
6257             //System.err.println("Attr.validateAnnotatedType: " + errtree + " type: " + type);
6258 
6259             if (type.isPrimitiveOrVoid()) {
6260                 return;
6261             }
6262 
6263             JCTree enclTr = errtree;
6264             Type enclTy = type;
6265 
6266             boolean repeat = true;
6267             while (repeat) {
6268                 if (enclTr.hasTag(TYPEAPPLY)) {
6269                     List<Type> tyargs = enclTy.getTypeArguments();
6270                     List<JCExpression> trargs = ((JCTypeApply)enclTr).getTypeArguments();
6271                     if (trargs.length() > 0) {
6272                         // Nothing to do for diamonds
6273                         if (tyargs.length() == trargs.length()) {
6274                             for (int i = 0; i < tyargs.length(); ++i) {
6275                                 validateAnnotatedType(trargs.get(i), tyargs.get(i));
6276                             }
6277                         }
6278                         // If the lengths don't match, it's either a diamond
6279                         // or some nested type that redundantly provides
6280                         // type arguments in the tree.
6281                     }
6282 
6283                     // Look at the clazz part of a generic type
6284                     enclTr = ((JCTree.JCTypeApply)enclTr).clazz;
6285                 }
6286 
6287                 if (enclTr.hasTag(SELECT)) {
6288                     enclTr = ((JCTree.JCFieldAccess)enclTr).getExpression();
6289                     if (enclTy != null &&
6290                             !enclTy.hasTag(NONE)) {
6291                         enclTy = enclTy.getEnclosingType();
6292                     }
6293                 } else if (enclTr.hasTag(ANNOTATED_TYPE)) {
6294                     JCAnnotatedType at = (JCTree.JCAnnotatedType) enclTr;
6295                     if (enclTy == null || enclTy.hasTag(NONE)) {
6296                         ListBuffer<Attribute.TypeCompound> onlyTypeAnnotationsBuf = new ListBuffer<>();
6297                         for (JCAnnotation an : at.getAnnotations()) {
6298                             if (chk.isTypeAnnotation(an, false)) {
6299                                 onlyTypeAnnotationsBuf.add((Attribute.TypeCompound) an.attribute);
6300                             }
6301                         }
6302                         List<Attribute.TypeCompound> onlyTypeAnnotations = onlyTypeAnnotationsBuf.toList();
6303                         if (!onlyTypeAnnotations.isEmpty()) {
6304                             Fragment annotationFragment = onlyTypeAnnotations.size() == 1 ?
6305                                     Fragments.TypeAnnotation1(onlyTypeAnnotations.head) :
6306                                     Fragments.TypeAnnotation(onlyTypeAnnotations);
6307                             JCDiagnostic.AnnotatedType annotatedType = new JCDiagnostic.AnnotatedType(
6308                                     type.stripMetadata().annotatedType(onlyTypeAnnotations));
6309                             log.error(at.underlyingType.pos(), Errors.TypeAnnotationInadmissible(annotationFragment,
6310                                     type.tsym.owner, annotatedType));
6311                         }
6312                         repeat = false;
6313                     }
6314                     enclTr = at.underlyingType;
6315                     // enclTy doesn't need to be changed
6316                 } else if (enclTr.hasTag(IDENT)) {
6317                     repeat = false;
6318                 } else if (enclTr.hasTag(JCTree.Tag.WILDCARD)) {
6319                     JCWildcard wc = (JCWildcard) enclTr;
6320                     if (wc.getKind() == JCTree.Kind.EXTENDS_WILDCARD ||
6321                             wc.getKind() == JCTree.Kind.SUPER_WILDCARD) {
6322                         validateAnnotatedType(wc.getBound(), wc.getBound().type);
6323                     } else {
6324                         // Nothing to do for UNBOUND
6325                     }
6326                     repeat = false;
6327                 } else if (enclTr.hasTag(TYPEARRAY)) {
6328                     JCArrayTypeTree art = (JCArrayTypeTree) enclTr;
6329                     validateAnnotatedType(art.getType(), art.elemtype.type);
6330                     repeat = false;
6331                 } else if (enclTr.hasTag(TYPEUNION)) {
6332                     JCTypeUnion ut = (JCTypeUnion) enclTr;
6333                     for (JCTree t : ut.getTypeAlternatives()) {
6334                         validateAnnotatedType(t, t.type);
6335                     }
6336                     repeat = false;
6337                 } else if (enclTr.hasTag(TYPEINTERSECTION)) {
6338                     JCTypeIntersection it = (JCTypeIntersection) enclTr;
6339                     for (JCTree t : it.getBounds()) {
6340                         validateAnnotatedType(t, t.type);
6341                     }
6342                     repeat = false;
6343                 } else if (enclTr.getKind() == JCTree.Kind.PRIMITIVE_TYPE ||
6344                            enclTr.getKind() == JCTree.Kind.ERRONEOUS) {
6345                     repeat = false;
6346                 } else {
6347                     Assert.error("Unexpected tree: " + enclTr + " with kind: " + enclTr.getKind() +
6348                             " within: "+ errtree + " with kind: " + errtree.getKind());
6349                 }
6350             }
6351         }
6352 
6353         private void checkForDeclarationAnnotations(List<? extends JCAnnotation> annotations,
6354                 Symbol sym) {
6355             // Ensure that no declaration annotations are present.
6356             // Note that a tree type might be an AnnotatedType with
6357             // empty annotations, if only declaration annotations were given.
6358             // This method will raise an error for such a type.
6359             for (JCAnnotation ai : annotations) {
6360                 if (!ai.type.isErroneous() &&
6361                         typeAnnotations.annotationTargetType(ai, ai.attribute, sym) == TypeAnnotations.AnnotationType.DECLARATION) {
6362                     log.error(ai.pos(), Errors.AnnotationTypeNotApplicableToType(ai.type));
6363                 }
6364             }
6365         }
6366     }
6367 
6368     // <editor-fold desc="post-attribution visitor">
6369 
6370     /**
6371      * Handle missing types/symbols in an AST. This routine is useful when
6372      * the compiler has encountered some errors (which might have ended up
6373      * terminating attribution abruptly); if the compiler is used in fail-over
6374      * mode (e.g. by an IDE) and the AST contains semantic errors, this routine
6375      * prevents NPE to be propagated during subsequent compilation steps.
6376      */
6377     public void postAttr(JCTree tree) {
6378         new PostAttrAnalyzer().scan(tree);
6379     }
6380 
6381     class PostAttrAnalyzer extends TreeScanner {
6382 
6383         private void initTypeIfNeeded(JCTree that) {
6384             if (that.type == null) {
6385                 if (that.hasTag(METHODDEF)) {
6386                     that.type = dummyMethodType((JCMethodDecl)that);
6387                 } else {
6388                     that.type = syms.unknownType;
6389                 }
6390             }
6391         }
6392 
6393         /* Construct a dummy method type. If we have a method declaration,
6394          * and the declared return type is void, then use that return type
6395          * instead of UNKNOWN to avoid spurious error messages in lambda
6396          * bodies (see:JDK-8041704).
6397          */
6398         private Type dummyMethodType(JCMethodDecl md) {
6399             Type restype = syms.unknownType;
6400             if (md != null && md.restype != null && md.restype.hasTag(TYPEIDENT)) {
6401                 JCPrimitiveTypeTree prim = (JCPrimitiveTypeTree)md.restype;
6402                 if (prim.typetag == VOID)
6403                     restype = syms.voidType;
6404             }
6405             return new MethodType(List.nil(), restype,
6406                                   List.nil(), syms.methodClass);
6407         }
6408         private Type dummyMethodType() {
6409             return dummyMethodType(null);
6410         }
6411 
6412         @Override
6413         public void scan(JCTree tree) {
6414             if (tree == null) return;
6415             if (tree instanceof JCExpression) {
6416                 initTypeIfNeeded(tree);
6417             }
6418             super.scan(tree);
6419         }
6420 
6421         @Override
6422         public void visitIdent(JCIdent that) {
6423             if (that.sym == null) {
6424                 that.sym = syms.unknownSymbol;
6425             }
6426         }
6427 
6428         @Override
6429         public void visitSelect(JCFieldAccess that) {
6430             if (that.sym == null) {
6431                 that.sym = syms.unknownSymbol;
6432             }
6433             super.visitSelect(that);
6434         }
6435 
6436         @Override
6437         public void visitClassDef(JCClassDecl that) {
6438             initTypeIfNeeded(that);
6439             if (that.sym == null) {
6440                 that.sym = new ClassSymbol(0, that.name, that.type, syms.noSymbol);
6441             }
6442             super.visitClassDef(that);
6443         }
6444 
6445         @Override
6446         public void visitMethodDef(JCMethodDecl that) {
6447             initTypeIfNeeded(that);
6448             if (that.sym == null) {
6449                 that.sym = new MethodSymbol(0, that.name, that.type, syms.noSymbol);
6450             }
6451             super.visitMethodDef(that);
6452         }
6453 
6454         @Override
6455         public void visitVarDef(JCVariableDecl that) {
6456             initTypeIfNeeded(that);
6457             if (that.sym == null) {
6458                 that.sym = new VarSymbol(0, that.name, that.type, syms.noSymbol);
6459                 that.sym.adr = 0;
6460             }
6461             if (that.vartype == null) {
6462                 that.vartype = make.at(Position.NOPOS).Erroneous();
6463             }
6464             super.visitVarDef(that);
6465         }
6466 
6467         @Override
6468         public void visitBindingPattern(JCBindingPattern that) {
6469             initTypeIfNeeded(that);
6470             initTypeIfNeeded(that.var);
6471             if (that.var.sym == null) {
6472                 that.var.sym = new BindingSymbol(0, that.var.name, that.var.type, syms.noSymbol);
6473                 that.var.sym.adr = 0;
6474             }
6475             super.visitBindingPattern(that);
6476         }
6477 
6478         @Override
6479         public void visitRecordPattern(JCRecordPattern that) {
6480             initTypeIfNeeded(that);
6481             if (that.record == null) {
6482                 that.record = new ClassSymbol(0, TreeInfo.name(that.deconstructor),
6483                                               that.type, syms.noSymbol);
6484             }
6485             if (that.fullComponentTypes == null) {
6486                 that.fullComponentTypes = List.nil();
6487             }
6488             super.visitRecordPattern(that);
6489         }
6490 
6491         @Override
6492         public void visitNewClass(JCNewClass that) {
6493             if (that.constructor == null) {
6494                 that.constructor = new MethodSymbol(0, names.init,
6495                         dummyMethodType(), syms.noSymbol);
6496             }
6497             if (that.constructorType == null) {
6498                 that.constructorType = syms.unknownType;
6499             }
6500             super.visitNewClass(that);
6501         }
6502 
6503         @Override
6504         public void visitAssignop(JCAssignOp that) {
6505             if (that.operator == null) {
6506                 that.operator = new OperatorSymbol(names.empty, dummyMethodType(),
6507                         -1, syms.noSymbol);
6508             }
6509             super.visitAssignop(that);
6510         }
6511 
6512         @Override
6513         public void visitBinary(JCBinary that) {
6514             if (that.operator == null) {
6515                 that.operator = new OperatorSymbol(names.empty, dummyMethodType(),
6516                         -1, syms.noSymbol);
6517             }
6518             super.visitBinary(that);
6519         }
6520 
6521         @Override
6522         public void visitUnary(JCUnary that) {
6523             if (that.operator == null) {
6524                 that.operator = new OperatorSymbol(names.empty, dummyMethodType(),
6525                         -1, syms.noSymbol);
6526             }
6527             super.visitUnary(that);
6528         }
6529 
6530         @Override
6531         public void visitReference(JCMemberReference that) {
6532             super.visitReference(that);
6533             if (that.sym == null) {
6534                 that.sym = new MethodSymbol(0, names.empty, dummyMethodType(),
6535                         syms.noSymbol);
6536             }
6537         }
6538     }
6539     // </editor-fold>
6540 
6541     public void setPackageSymbols(JCExpression pid, Symbol pkg) {
6542         new TreeScanner() {
6543             Symbol packge = pkg;
6544             @Override
6545             public void visitIdent(JCIdent that) {
6546                 that.sym = packge;
6547             }
6548 
6549             @Override
6550             public void visitSelect(JCFieldAccess that) {
6551                 that.sym = packge;
6552                 packge = packge.owner;
6553                 super.visitSelect(that);
6554             }
6555         }.scan(pid);
6556     }
6557 
6558 }