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 boolean captureMRefReturnType;
 128 
 129     public static Attr instance(Context context) {
 130         Attr instance = context.get(attrKey);
 131         if (instance == null)
 132             instance = new Attr(context);
 133         return instance;
 134     }
 135 
 136     @SuppressWarnings("this-escape")
 137     protected Attr(Context context) {
 138         context.put(attrKey, this);
 139 
 140         names = Names.instance(context);
 141         log = Log.instance(context);
 142         lintMapper = LintMapper.instance(context);
 143         syms = Symtab.instance(context);
 144         rs = Resolve.instance(context);
 145         operators = Operators.instance(context);
 146         chk = Check.instance(context);
 147         flow = Flow.instance(context);
 148         memberEnter = MemberEnter.instance(context);
 149         typeEnter = TypeEnter.instance(context);
 150         make = TreeMaker.instance(context);
 151         enter = Enter.instance(context);
 152         infer = Infer.instance(context);
 153         analyzer = Analyzer.instance(context);
 154         deferredAttr = DeferredAttr.instance(context);
 155         cfolder = ConstFold.instance(context);
 156         target = Target.instance(context);
 157         types = Types.instance(context);
 158         preview = Preview.instance(context);
 159         diags = JCDiagnostic.Factory.instance(context);
 160         annotate = Annotate.instance(context);
 161         typeAnnotations = TypeAnnotations.instance(context);
 162         typeEnvs = TypeEnvs.instance(context);
 163         dependencies = Dependencies.instance(context);
 164         argumentAttr = ArgumentAttr.instance(context);
 165         matchBindingsComputer = MatchBindingsComputer.instance(context);
 166         attrRecover = AttrRecover.instance(context);
 167 
 168         Options options = Options.instance(context);
 169 
 170         Source source = Source.instance(context);
 171         allowReifiableTypesInInstanceof = Feature.REIFIABLE_TYPES_INSTANCEOF.allowedInSource(source);
 172         allowRecords = Feature.RECORDS.allowedInSource(source);
 173         allowPatternSwitch = (preview.isEnabled() || !preview.isPreview(Feature.PATTERN_SWITCH)) &&
 174                              Feature.PATTERN_SWITCH.allowedInSource(source);
 175         allowUnconditionalPatternsInstanceOf =
 176                              Feature.UNCONDITIONAL_PATTERN_IN_INSTANCEOF.allowedInSource(source);
 177         sourceName = source.name;
 178         useBeforeDeclarationWarning = options.isSet("useBeforeDeclarationWarning");
 179         captureMRefReturnType = Source.Feature.CAPTURE_MREF_RETURN_TYPE.allowedInSource(source);
 180 
 181         statInfo = new ResultInfo(KindSelector.NIL, Type.noType);
 182         varAssignmentInfo = new ResultInfo(KindSelector.ASG, Type.noType);
 183         varAssignmentOpInfo = new ResultInfo(KindSelector.of(KindSelector.VAL, KindSelector.ASG), Type.noType);
 184         unknownExprInfo = new ResultInfo(KindSelector.VAL, Type.noType);
 185         methodAttrInfo = new MethodAttrInfo();
 186         unknownTypeInfo = new ResultInfo(KindSelector.TYP, Type.noType);
 187         unknownTypeExprInfo = new ResultInfo(KindSelector.VAL_TYP, Type.noType);
 188         recoveryInfo = new RecoveryInfo(deferredAttr.emptyDeferredAttrContext);
 189         initBlockType = new MethodType(List.nil(), syms.voidType, List.nil(), syms.methodClass);
 190         allowValueClasses = preview.isEnabled() && Feature.VALUE_CLASSES.allowedInSource(source);
 191     }
 192 
 193     /** Switch: reifiable types in instanceof enabled?
 194      */
 195     boolean allowReifiableTypesInInstanceof;
 196 
 197     /** Are records allowed
 198      */
 199     private final boolean allowRecords;
 200 
 201     /** Are patterns in switch allowed
 202      */
 203     private final boolean allowPatternSwitch;
 204 
 205     /** Are unconditional patterns in instanceof allowed
 206      */
 207     private final boolean allowUnconditionalPatternsInstanceOf;
 208 
 209     /** Are value classes allowed
 210      */
 211     private final boolean allowValueClasses;
 212 
 213     /**
 214      * Switch: warn about use of variable before declaration?
 215      * RFE: 6425594
 216      */
 217     boolean useBeforeDeclarationWarning;
 218 
 219     /**
 220      * Switch: name of source level; used for error reporting.
 221      */
 222     String sourceName;
 223 
 224     /** Check kind and type of given tree against protokind and prototype.
 225      *  If check succeeds, store type in tree and return it.
 226      *  If check fails, store errType in tree and return it.
 227      *  No checks are performed if the prototype is a method type.
 228      *  It is not necessary in this case since we know that kind and type
 229      *  are correct.
 230      *
 231      *  @param tree     The tree whose kind and type is checked
 232      *  @param found    The computed type of the tree
 233      *  @param ownkind  The computed kind of the tree
 234      *  @param resultInfo  The expected result of the tree
 235      */
 236     Type check(final JCTree tree,
 237                final Type found,
 238                final KindSelector ownkind,
 239                final ResultInfo resultInfo) {
 240         InferenceContext inferenceContext = resultInfo.checkContext.inferenceContext();
 241         Type owntype;
 242         boolean shouldCheck = !found.hasTag(ERROR) &&
 243                 !resultInfo.pt.hasTag(METHOD) &&
 244                 !resultInfo.pt.hasTag(FORALL);
 245         if (shouldCheck && !ownkind.subset(resultInfo.pkind)) {
 246             log.error(tree.pos(),
 247                       Errors.UnexpectedType(resultInfo.pkind.kindNames(),
 248                                             ownkind.kindNames()));
 249             owntype = types.createErrorType(found);
 250         } else if (inferenceContext.free(found)) {
 251             //delay the check if there are inference variables in the found type
 252             //this means we are dealing with a partially inferred poly expression
 253             owntype = shouldCheck ? resultInfo.pt : found;
 254             if (resultInfo.checkMode.installPostInferenceHook()) {
 255                 inferenceContext.addFreeTypeListener(List.of(found),
 256                         instantiatedContext -> {
 257                             ResultInfo pendingResult =
 258                                     resultInfo.dup(inferenceContext.asInstType(resultInfo.pt));
 259                             check(tree, inferenceContext.asInstType(found), ownkind, pendingResult);
 260                         });
 261             }
 262         } else {
 263             owntype = shouldCheck ?
 264             resultInfo.check(tree, found) :
 265             found;
 266         }
 267         if (resultInfo.checkMode.updateTreeType()) {
 268             tree.type = owntype;
 269         }
 270         return owntype;
 271     }
 272 
 273     /** Is given blank final variable assignable, i.e. in a scope where it
 274      *  may be assigned to even though it is final?
 275      *  @param v      The blank final variable.
 276      *  @param env    The current environment.
 277      */
 278     boolean isAssignableAsBlankFinal(VarSymbol v, Env<AttrContext> env) {
 279         Symbol owner = env.info.scope.owner;
 280            // owner refers to the innermost variable, method or
 281            // initializer block declaration at this point.
 282         boolean isAssignable =
 283             v.owner == owner
 284             ||
 285             ((owner.name == names.init ||    // i.e. we are in a constructor
 286               owner.kind == VAR ||           // i.e. we are in a variable initializer
 287               (owner.flags() & BLOCK) != 0)  // i.e. we are in an initializer block
 288              &&
 289              v.owner == owner.owner
 290              &&
 291              ((v.flags() & STATIC) != 0) == Resolve.isStatic(env));
 292         boolean insideCompactConstructor = env.enclMethod != null && TreeInfo.isCompactConstructor(env.enclMethod);
 293         return isAssignable & !insideCompactConstructor;
 294     }
 295 
 296     /** Check that variable can be assigned to.
 297      *  @param pos    The current source code position.
 298      *  @param v      The assigned variable
 299      *  @param base   If the variable is referred to in a Select, the part
 300      *                to the left of the `.', null otherwise.
 301      *  @param env    The current environment.
 302      */
 303     void checkAssignable(DiagnosticPosition pos, VarSymbol v, JCTree base, Env<AttrContext> env) {
 304         if (v.name == names._this) {
 305             log.error(pos, Errors.CantAssignValToThis);
 306             return;
 307         }
 308         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             return;
 320         }
















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