1 /*
   2  * Copyright (c) 1999, 2022, 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.EnhancedForLoopTree;
  38 import com.sun.source.tree.IdentifierTree;
  39 import com.sun.source.tree.MemberReferenceTree.ReferenceMode;
  40 import com.sun.source.tree.MemberSelectTree;
  41 import com.sun.source.tree.TreeVisitor;
  42 import com.sun.source.util.SimpleTreeVisitor;
  43 import com.sun.tools.javac.code.*;
  44 import com.sun.tools.javac.code.Lint.LintCategory;
  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.TypeMetadata.Annotations;
  50 import com.sun.tools.javac.code.Types.FunctionDescriptorLookupError;
  51 import com.sun.tools.javac.comp.ArgumentAttr.LocalCacheContext;
  52 import com.sun.tools.javac.comp.Check.CheckContext;
  53 import com.sun.tools.javac.comp.DeferredAttr.AttrMode;
  54 import com.sun.tools.javac.comp.MatchBindingsComputer.MatchBindings;
  55 import com.sun.tools.javac.jvm.*;
  56 
  57 import static com.sun.tools.javac.resources.CompilerProperties.Fragments.Diamond;
  58 import static com.sun.tools.javac.resources.CompilerProperties.Fragments.DiamondInvalidArg;
  59 import static com.sun.tools.javac.resources.CompilerProperties.Fragments.DiamondInvalidArgs;
  60 
  61 import com.sun.tools.javac.resources.CompilerProperties.Errors;
  62 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
  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 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticFlag;
  84 
  85 /** This is the main context-dependent analysis phase in GJC. It
  86  *  encompasses name resolution, type checking and constant folding as
  87  *  subtasks. Some subtasks involve auxiliary classes.
  88  *  @see Check
  89  *  @see Resolve
  90  *  @see ConstFold
  91  *  @see Infer
  92  *
  93  *  <p><b>This is NOT part of any supported API.
  94  *  If you write code that depends on this, you do so at your own risk.
  95  *  This code and its internal interfaces are subject to change or
  96  *  deletion without notice.</b>
  97  */
  98 public class Attr extends JCTree.Visitor {
  99     protected static final Context.Key<Attr> attrKey = new Context.Key<>();
 100 
 101     final Names names;
 102     final Log log;
 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 DeferredLintHandler deferredLintHandler;
 122     final TypeEnvs typeEnvs;
 123     final Dependencies dependencies;
 124     final Annotate annotate;
 125     final ArgumentAttr argumentAttr;
 126     final MatchBindingsComputer matchBindingsComputer;
 127     final AttrRecover attrRecover;
 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     protected Attr(Context context) {
 137         context.put(attrKey, this);
 138 
 139         names = Names.instance(context);
 140         log = Log.instance(context);
 141         syms = Symtab.instance(context);
 142         rs = Resolve.instance(context);
 143         operators = Operators.instance(context);
 144         chk = Check.instance(context);
 145         flow = Flow.instance(context);
 146         memberEnter = MemberEnter.instance(context);
 147         typeEnter = TypeEnter.instance(context);
 148         make = TreeMaker.instance(context);
 149         enter = Enter.instance(context);
 150         infer = Infer.instance(context);
 151         analyzer = Analyzer.instance(context);
 152         deferredAttr = DeferredAttr.instance(context);
 153         cfolder = ConstFold.instance(context);
 154         target = Target.instance(context);
 155         types = Types.instance(context);
 156         preview = Preview.instance(context);
 157         diags = JCDiagnostic.Factory.instance(context);
 158         annotate = Annotate.instance(context);
 159         typeAnnotations = TypeAnnotations.instance(context);
 160         deferredLintHandler = DeferredLintHandler.instance(context);
 161         typeEnvs = TypeEnvs.instance(context);
 162         dependencies = Dependencies.instance(context);
 163         argumentAttr = ArgumentAttr.instance(context);
 164         matchBindingsComputer = MatchBindingsComputer.instance(context);
 165         attrRecover = AttrRecover.instance(context);
 166 
 167         Options options = Options.instance(context);
 168 
 169         Source source = Source.instance(context);
 170         allowReifiableTypesInInstanceof = Feature.REIFIABLE_TYPES_INSTANCEOF.allowedInSource(source);
 171         allowRecords = Feature.RECORDS.allowedInSource(source);
 172         allowPatternSwitch = (preview.isEnabled() || !preview.isPreview(Feature.PATTERN_SWITCH)) &&
 173                              Feature.PATTERN_SWITCH.allowedInSource(source);
 174         allowUnconditionalPatternsInstanceOf = (preview.isEnabled() || !preview.isPreview(Feature.UNCONDITIONAL_PATTERN_IN_INSTANCEOF)) &&
 175                                      Feature.UNCONDITIONAL_PATTERN_IN_INSTANCEOF.allowedInSource(source);
 176         sourceName = source.name;
 177         useBeforeDeclarationWarning = options.isSet("useBeforeDeclarationWarning");
 178 
 179         statInfo = new ResultInfo(KindSelector.NIL, Type.noType);
 180         varAssignmentInfo = new ResultInfo(KindSelector.ASG, Type.noType);
 181         unknownExprInfo = new ResultInfo(KindSelector.VAL, Type.noType);
 182         methodAttrInfo = new MethodAttrInfo();
 183         unknownTypeInfo = new ResultInfo(KindSelector.TYP, Type.noType);
 184         unknownTypeExprInfo = new ResultInfo(KindSelector.VAL_TYP, Type.noType);
 185         recoveryInfo = new RecoveryInfo(deferredAttr.emptyDeferredAttrContext);
 186     }
 187 
 188     /** Switch: reifiable types in instanceof enabled?
 189      */
 190     boolean allowReifiableTypesInInstanceof;
 191 
 192     /** Are records allowed
 193      */
 194     private final boolean allowRecords;
 195 
 196     /** Are patterns in switch allowed
 197      */
 198     private final boolean allowPatternSwitch;
 199 
 200     /** Are unconditional patterns in instanceof allowed
 201      */
 202     private final boolean allowUnconditionalPatternsInstanceOf;
 203 
 204     /**
 205      * Switch: warn about use of variable before declaration?
 206      * RFE: 6425594
 207      */
 208     boolean useBeforeDeclarationWarning;
 209 
 210     /**
 211      * Switch: name of source level; used for error reporting.
 212      */
 213     String sourceName;
 214 
 215     /** Check kind and type of given tree against protokind and prototype.
 216      *  If check succeeds, store type in tree and return it.
 217      *  If check fails, store errType in tree and return it.
 218      *  No checks are performed if the prototype is a method type.
 219      *  It is not necessary in this case since we know that kind and type
 220      *  are correct.
 221      *
 222      *  @param tree     The tree whose kind and type is checked
 223      *  @param found    The computed type of the tree
 224      *  @param ownkind  The computed kind of the tree
 225      *  @param resultInfo  The expected result of the tree
 226      */
 227     Type check(final JCTree tree,
 228                final Type found,
 229                final KindSelector ownkind,
 230                final ResultInfo resultInfo) {
 231         InferenceContext inferenceContext = resultInfo.checkContext.inferenceContext();
 232         Type owntype;
 233         boolean shouldCheck = !found.hasTag(ERROR) &&
 234                 !resultInfo.pt.hasTag(METHOD) &&
 235                 !resultInfo.pt.hasTag(FORALL);
 236         if (shouldCheck && !ownkind.subset(resultInfo.pkind)) {
 237             log.error(tree.pos(),
 238                       Errors.UnexpectedType(resultInfo.pkind.kindNames(),
 239                                             ownkind.kindNames()));
 240             owntype = types.createErrorType(found);
 241         } else if (inferenceContext.free(found)) {
 242             //delay the check if there are inference variables in the found type
 243             //this means we are dealing with a partially inferred poly expression
 244             owntype = shouldCheck ? resultInfo.pt : found;
 245             if (resultInfo.checkMode.installPostInferenceHook()) {
 246                 inferenceContext.addFreeTypeListener(List.of(found),
 247                         instantiatedContext -> {
 248                             ResultInfo pendingResult =
 249                                     resultInfo.dup(inferenceContext.asInstType(resultInfo.pt));
 250                             check(tree, inferenceContext.asInstType(found), ownkind, pendingResult);
 251                         });
 252             }
 253         } else {
 254             owntype = shouldCheck ?
 255             resultInfo.check(tree, found) :
 256             found;
 257         }
 258         if (resultInfo.checkMode.updateTreeType()) {
 259             tree.type = owntype;
 260         }
 261         return owntype;
 262     }
 263 
 264     /** Is given blank final variable assignable, i.e. in a scope where it
 265      *  may be assigned to even though it is final?
 266      *  @param v      The blank final variable.
 267      *  @param env    The current environment.
 268      */
 269     boolean isAssignableAsBlankFinal(VarSymbol v, Env<AttrContext> env) {
 270         Symbol owner = env.info.scope.owner;
 271            // owner refers to the innermost variable, method or
 272            // initializer block declaration at this point.
 273         boolean isAssignable =
 274             v.owner == owner
 275             ||
 276             ((owner.name == names.init ||    // i.e. we are in a constructor
 277               owner.kind == VAR ||           // i.e. we are in a variable initializer
 278               (owner.flags() & BLOCK) != 0)  // i.e. we are in an initializer block
 279              &&
 280              v.owner == owner.owner
 281              &&
 282              ((v.flags() & STATIC) != 0) == Resolve.isStatic(env));
 283         boolean insideCompactConstructor = env.enclMethod != null && TreeInfo.isCompactConstructor(env.enclMethod);
 284         return isAssignable & !insideCompactConstructor;
 285     }
 286 
 287     /** Check that variable can be assigned to.
 288      *  @param pos    The current source code position.
 289      *  @param v      The assigned variable
 290      *  @param base   If the variable is referred to in a Select, the part
 291      *                to the left of the `.', null otherwise.
 292      *  @param env    The current environment.
 293      */
 294     void checkAssignable(DiagnosticPosition pos, VarSymbol v, JCTree base, Env<AttrContext> env) {
 295         if (v.name == names._this) {
 296             log.error(pos, Errors.CantAssignValToThis);
 297         } else if ((v.flags() & FINAL) != 0 &&
 298             ((v.flags() & HASINIT) != 0
 299              ||
 300              !((base == null ||
 301                TreeInfo.isThisQualifier(base)) &&
 302                isAssignableAsBlankFinal(v, env)))) {
 303             if (v.isResourceVariable()) { //TWR resource
 304                 log.error(pos, Errors.TryResourceMayNotBeAssigned(v));
 305             } else {
 306                 log.error(pos, Errors.CantAssignValToFinalVar(v));
 307             }
 308         }
 309     }
 310 
 311     /** Does tree represent a static reference to an identifier?
 312      *  It is assumed that tree is either a SELECT or an IDENT.
 313      *  We have to weed out selects from non-type names here.
 314      *  @param tree    The candidate tree.
 315      */
 316     boolean isStaticReference(JCTree tree) {
 317         if (tree.hasTag(SELECT)) {
 318             Symbol lsym = TreeInfo.symbol(((JCFieldAccess) tree).selected);
 319             if (lsym == null || lsym.kind != TYP) {
 320                 return false;
 321             }
 322         }
 323         return true;
 324     }
 325 
 326     /** Is this symbol a type?
 327      */
 328     static boolean isType(Symbol sym) {
 329         return sym != null && sym.kind == TYP;
 330     }
 331 
 332     /** The current `this' symbol.
 333      *  @param env    The current environment.
 334      */
 335     Symbol thisSym(DiagnosticPosition pos, Env<AttrContext> env) {
 336         return rs.resolveSelf(pos, env, env.enclClass.sym, names._this);
 337     }
 338 
 339     /** Attribute a parsed identifier.
 340      * @param tree Parsed identifier name
 341      * @param topLevel The toplevel to use
 342      */
 343     public Symbol attribIdent(JCTree tree, JCCompilationUnit topLevel) {
 344         Env<AttrContext> localEnv = enter.topLevelEnv(topLevel);
 345         localEnv.enclClass = make.ClassDef(make.Modifiers(0),
 346                                            syms.errSymbol.name,
 347                                            null, null, null, null);
 348         localEnv.enclClass.sym = syms.errSymbol;
 349         return attribIdent(tree, localEnv);
 350     }
 351 
 352     /** Attribute a parsed identifier.
 353      * @param tree Parsed identifier name
 354      * @param env The env to use
 355      */
 356     public Symbol attribIdent(JCTree tree, Env<AttrContext> env) {
 357         return tree.accept(identAttributer, env);
 358     }
 359     // where
 360         private TreeVisitor<Symbol,Env<AttrContext>> identAttributer = new IdentAttributer();
 361         private class IdentAttributer extends SimpleTreeVisitor<Symbol,Env<AttrContext>> {
 362             @Override @DefinedBy(Api.COMPILER_TREE)
 363             public Symbol visitMemberSelect(MemberSelectTree node, Env<AttrContext> env) {
 364                 Symbol site = visit(node.getExpression(), env);
 365                 if (site.kind == ERR || site.kind == ABSENT_TYP || site.kind == HIDDEN)
 366                     return site;
 367                 Name name = (Name)node.getIdentifier();
 368                 if (site.kind == PCK) {
 369                     env.toplevel.packge = (PackageSymbol)site;
 370                     return rs.findIdentInPackage(null, env, (TypeSymbol)site, name,
 371                             KindSelector.TYP_PCK);
 372                 } else {
 373                     env.enclClass.sym = (ClassSymbol)site;
 374                     return rs.findMemberType(env, site.asType(), name, (TypeSymbol)site);
 375                 }
 376             }
 377 
 378             @Override @DefinedBy(Api.COMPILER_TREE)
 379             public Symbol visitIdentifier(IdentifierTree node, Env<AttrContext> env) {
 380                 return rs.findIdent(null, env, (Name)node.getName(), KindSelector.TYP_PCK);
 381             }
 382         }
 383 
 384     public Type coerce(Type etype, Type ttype) {
 385         return cfolder.coerce(etype, ttype);
 386     }
 387 
 388     public Type attribType(JCTree node, TypeSymbol sym) {
 389         Env<AttrContext> env = typeEnvs.get(sym);
 390         Env<AttrContext> localEnv = env.dup(node, env.info.dup());
 391         return attribTree(node, localEnv, unknownTypeInfo);
 392     }
 393 
 394     public Type attribImportQualifier(JCImport tree, Env<AttrContext> env) {
 395         // Attribute qualifying package or class.
 396         JCFieldAccess s = (JCFieldAccess)tree.qualid;
 397         return attribTree(s.selected, env,
 398                           new ResultInfo(tree.staticImport ?
 399                                          KindSelector.TYP : KindSelector.TYP_PCK,
 400                        Type.noType));
 401     }
 402 
 403     public Env<AttrContext> attribExprToTree(JCTree expr, Env<AttrContext> env, JCTree tree) {
 404         return attribToTree(expr, env, tree, unknownExprInfo);
 405     }
 406 
 407     public Env<AttrContext> attribStatToTree(JCTree stmt, Env<AttrContext> env, JCTree tree) {
 408         return attribToTree(stmt, env, tree, statInfo);
 409     }
 410 
 411     private Env<AttrContext> attribToTree(JCTree root, Env<AttrContext> env, JCTree tree, ResultInfo resultInfo) {
 412         breakTree = tree;
 413         JavaFileObject prev = log.useSource(env.toplevel.sourcefile);
 414         try {
 415             deferredAttr.attribSpeculative(root, env, resultInfo,
 416                     null, DeferredAttr.AttributionMode.ATTRIB_TO_TREE,
 417                     argumentAttr.withLocalCacheContext());
 418             attrRecover.doRecovery();
 419         } catch (BreakAttr b) {
 420             return b.env;
 421         } catch (AssertionError ae) {
 422             if (ae.getCause() instanceof BreakAttr breakAttr) {
 423                 return breakAttr.env;
 424             } else {
 425                 throw ae;
 426             }
 427         } finally {
 428             breakTree = null;
 429             log.useSource(prev);
 430         }
 431         return env;
 432     }
 433 
 434     private JCTree breakTree = null;
 435 
 436     private static class BreakAttr extends RuntimeException {
 437         static final long serialVersionUID = -6924771130405446405L;
 438         private transient Env<AttrContext> env;
 439         private BreakAttr(Env<AttrContext> env) {
 440             this.env = env;
 441         }
 442     }
 443 
 444     /**
 445      * Mode controlling behavior of Attr.Check
 446      */
 447     enum CheckMode {
 448 
 449         NORMAL,
 450 
 451         /**
 452          * Mode signalling 'fake check' - skip tree update. A side-effect of this mode is
 453          * that the captured var cache in {@code InferenceContext} will be used in read-only
 454          * mode when performing inference checks.
 455          */
 456         NO_TREE_UPDATE {
 457             @Override
 458             public boolean updateTreeType() {
 459                 return false;
 460             }
 461         },
 462         /**
 463          * Mode signalling that caller will manage free types in tree decorations.
 464          */
 465         NO_INFERENCE_HOOK {
 466             @Override
 467             public boolean installPostInferenceHook() {
 468                 return false;
 469             }
 470         };
 471 
 472         public boolean updateTreeType() {
 473             return true;
 474         }
 475         public boolean installPostInferenceHook() {
 476             return true;
 477         }
 478     }
 479 
 480 
 481     class ResultInfo {
 482         final KindSelector pkind;
 483         final Type pt;
 484         final CheckContext checkContext;
 485         final CheckMode checkMode;
 486 
 487         ResultInfo(KindSelector pkind, Type pt) {
 488             this(pkind, pt, chk.basicHandler, CheckMode.NORMAL);
 489         }
 490 
 491         ResultInfo(KindSelector pkind, Type pt, CheckMode checkMode) {
 492             this(pkind, pt, chk.basicHandler, checkMode);
 493         }
 494 
 495         protected ResultInfo(KindSelector pkind,
 496                              Type pt, CheckContext checkContext) {
 497             this(pkind, pt, checkContext, CheckMode.NORMAL);
 498         }
 499 
 500         protected ResultInfo(KindSelector pkind,
 501                              Type pt, CheckContext checkContext, CheckMode checkMode) {
 502             this.pkind = pkind;
 503             this.pt = pt;
 504             this.checkContext = checkContext;
 505             this.checkMode = checkMode;
 506         }
 507 
 508         /**
 509          * Should {@link Attr#attribTree} use the {@ArgumentAttr} visitor instead of this one?
 510          * @param tree The tree to be type-checked.
 511          * @return true if {@ArgumentAttr} should be used.
 512          */
 513         protected boolean needsArgumentAttr(JCTree tree) { return false; }
 514 
 515         protected Type check(final DiagnosticPosition pos, final Type found) {
 516             return chk.checkType(pos, found, pt, checkContext);
 517         }
 518 
 519         protected ResultInfo dup(Type newPt) {
 520             return new ResultInfo(pkind, newPt, checkContext, checkMode);
 521         }
 522 
 523         protected ResultInfo dup(CheckContext newContext) {
 524             return new ResultInfo(pkind, pt, newContext, checkMode);
 525         }
 526 
 527         protected ResultInfo dup(Type newPt, CheckContext newContext) {
 528             return new ResultInfo(pkind, newPt, newContext, checkMode);
 529         }
 530 
 531         protected ResultInfo dup(Type newPt, CheckContext newContext, CheckMode newMode) {
 532             return new ResultInfo(pkind, newPt, newContext, newMode);
 533         }
 534 
 535         protected ResultInfo dup(CheckMode newMode) {
 536             return new ResultInfo(pkind, pt, checkContext, newMode);
 537         }
 538 
 539         @Override
 540         public String toString() {
 541             if (pt != null) {
 542                 return pt.toString();
 543             } else {
 544                 return "";
 545             }
 546         }
 547     }
 548 
 549     class MethodAttrInfo extends ResultInfo {
 550         public MethodAttrInfo() {
 551             this(chk.basicHandler);
 552         }
 553 
 554         public MethodAttrInfo(CheckContext checkContext) {
 555             super(KindSelector.VAL, Infer.anyPoly, checkContext);
 556         }
 557 
 558         @Override
 559         protected boolean needsArgumentAttr(JCTree tree) {
 560             return true;
 561         }
 562 
 563         protected ResultInfo dup(Type newPt) {
 564             throw new IllegalStateException();
 565         }
 566 
 567         protected ResultInfo dup(CheckContext newContext) {
 568             return new MethodAttrInfo(newContext);
 569         }
 570 
 571         protected ResultInfo dup(Type newPt, CheckContext newContext) {
 572             throw new IllegalStateException();
 573         }
 574 
 575         protected ResultInfo dup(Type newPt, CheckContext newContext, CheckMode newMode) {
 576             throw new IllegalStateException();
 577         }
 578 
 579         protected ResultInfo dup(CheckMode newMode) {
 580             throw new IllegalStateException();
 581         }
 582     }
 583 
 584     class RecoveryInfo extends ResultInfo {
 585 
 586         public RecoveryInfo(final DeferredAttr.DeferredAttrContext deferredAttrContext) {
 587             this(deferredAttrContext, Type.recoveryType);
 588         }
 589 
 590         public RecoveryInfo(final DeferredAttr.DeferredAttrContext deferredAttrContext, Type pt) {
 591             super(KindSelector.VAL, pt, new Check.NestedCheckContext(chk.basicHandler) {
 592                 @Override
 593                 public DeferredAttr.DeferredAttrContext deferredAttrContext() {
 594                     return deferredAttrContext;
 595                 }
 596                 @Override
 597                 public boolean compatible(Type found, Type req, Warner warn) {
 598                     return true;
 599                 }
 600                 @Override
 601                 public void report(DiagnosticPosition pos, JCDiagnostic details) {
 602                     boolean needsReport = pt == Type.recoveryType ||
 603                             (details.getDiagnosticPosition() != null &&
 604                             details.getDiagnosticPosition().getTree().hasTag(LAMBDA));
 605                     if (needsReport) {
 606                         chk.basicHandler.report(pos, details);
 607                     }
 608                 }
 609             });
 610         }
 611     }
 612 
 613     final ResultInfo statInfo;
 614     final ResultInfo varAssignmentInfo;
 615     final ResultInfo methodAttrInfo;
 616     final ResultInfo unknownExprInfo;
 617     final ResultInfo unknownTypeInfo;
 618     final ResultInfo unknownTypeExprInfo;
 619     final ResultInfo recoveryInfo;
 620 
 621     Type pt() {
 622         return resultInfo.pt;
 623     }
 624 
 625     KindSelector pkind() {
 626         return resultInfo.pkind;
 627     }
 628 
 629 /* ************************************************************************
 630  * Visitor methods
 631  *************************************************************************/
 632 
 633     /** Visitor argument: the current environment.
 634      */
 635     Env<AttrContext> env;
 636 
 637     /** Visitor argument: the currently expected attribution result.
 638      */
 639     ResultInfo resultInfo;
 640 
 641     /** Visitor result: the computed type.
 642      */
 643     Type result;
 644 
 645     MatchBindings matchBindings = MatchBindingsComputer.EMPTY;
 646 
 647     /** Visitor method: attribute a tree, catching any completion failure
 648      *  exceptions. Return the tree's type.
 649      *
 650      *  @param tree    The tree to be visited.
 651      *  @param env     The environment visitor argument.
 652      *  @param resultInfo   The result info visitor argument.
 653      */
 654     Type attribTree(JCTree tree, Env<AttrContext> env, ResultInfo resultInfo) {
 655         Env<AttrContext> prevEnv = this.env;
 656         ResultInfo prevResult = this.resultInfo;
 657         try {
 658             this.env = env;
 659             this.resultInfo = resultInfo;
 660             if (resultInfo.needsArgumentAttr(tree)) {
 661                 result = argumentAttr.attribArg(tree, env);
 662             } else {
 663                 tree.accept(this);
 664             }
 665             matchBindings = matchBindingsComputer.finishBindings(tree,
 666                                                                  matchBindings);
 667             if (tree == breakTree &&
 668                     resultInfo.checkContext.deferredAttrContext().mode == AttrMode.CHECK) {
 669                 breakTreeFound(copyEnv(env));
 670             }
 671             return result;
 672         } catch (CompletionFailure ex) {
 673             tree.type = syms.errType;
 674             return chk.completionError(tree.pos(), ex);
 675         } finally {
 676             this.env = prevEnv;
 677             this.resultInfo = prevResult;
 678         }
 679     }
 680 
 681     protected void breakTreeFound(Env<AttrContext> env) {
 682         throw new BreakAttr(env);
 683     }
 684 
 685     Env<AttrContext> copyEnv(Env<AttrContext> env) {
 686         Env<AttrContext> newEnv =
 687                 env.dup(env.tree, env.info.dup(copyScope(env.info.scope)));
 688         if (newEnv.outer != null) {
 689             newEnv.outer = copyEnv(newEnv.outer);
 690         }
 691         return newEnv;
 692     }
 693 
 694     WriteableScope copyScope(WriteableScope sc) {
 695         WriteableScope newScope = WriteableScope.create(sc.owner);
 696         List<Symbol> elemsList = List.nil();
 697         for (Symbol sym : sc.getSymbols()) {
 698             elemsList = elemsList.prepend(sym);
 699         }
 700         for (Symbol s : elemsList) {
 701             newScope.enter(s);
 702         }
 703         return newScope;
 704     }
 705 
 706     /** Derived visitor method: attribute an expression tree.
 707      */
 708     public Type attribExpr(JCTree tree, Env<AttrContext> env, Type pt) {
 709         return attribTree(tree, env, new ResultInfo(KindSelector.VAL, !pt.hasTag(ERROR) ? pt : Type.noType));
 710     }
 711 
 712     /** Derived visitor method: attribute an expression tree with
 713      *  no constraints on the computed type.
 714      */
 715     public Type attribExpr(JCTree tree, Env<AttrContext> env) {
 716         return attribTree(tree, env, unknownExprInfo);
 717     }
 718 
 719     /** Derived visitor method: attribute a type tree.
 720      */
 721     public Type attribType(JCTree tree, Env<AttrContext> env) {
 722         Type result = attribType(tree, env, Type.noType);
 723         return result;
 724     }
 725 
 726     /** Derived visitor method: attribute a type tree.
 727      */
 728     Type attribType(JCTree tree, Env<AttrContext> env, Type pt) {
 729         Type result = attribTree(tree, env, new ResultInfo(KindSelector.TYP, pt));
 730         return result;
 731     }
 732 
 733     /** Derived visitor method: attribute a statement or definition tree.
 734      */
 735     public Type attribStat(JCTree tree, Env<AttrContext> env) {
 736         Env<AttrContext> analyzeEnv = analyzer.copyEnvIfNeeded(tree, env);
 737         Type result = attribTree(tree, env, statInfo);
 738         analyzer.analyzeIfNeeded(tree, analyzeEnv);
 739         attrRecover.doRecovery();
 740         return result;
 741     }
 742 
 743     /** Attribute a list of expressions, returning a list of types.
 744      */
 745     List<Type> attribExprs(List<JCExpression> trees, Env<AttrContext> env, Type pt) {
 746         ListBuffer<Type> ts = new ListBuffer<>();
 747         for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail)
 748             ts.append(attribExpr(l.head, env, pt));
 749         return ts.toList();
 750     }
 751 
 752     /** Attribute a list of statements, returning nothing.
 753      */
 754     <T extends JCTree> void attribStats(List<T> trees, Env<AttrContext> env) {
 755         for (List<T> l = trees; l.nonEmpty(); l = l.tail)
 756             attribStat(l.head, env);
 757     }
 758 
 759     /** Attribute the arguments in a method call, returning the method kind.
 760      */
 761     KindSelector attribArgs(KindSelector initialKind, List<JCExpression> trees, Env<AttrContext> env, ListBuffer<Type> argtypes) {
 762         KindSelector kind = initialKind;
 763         for (JCExpression arg : trees) {
 764             Type argtype = chk.checkNonVoid(arg, attribTree(arg, env, methodAttrInfo));
 765             if (argtype.hasTag(DEFERRED)) {
 766                 kind = KindSelector.of(KindSelector.POLY, kind);
 767             }
 768             argtypes.append(argtype);
 769         }
 770         return kind;
 771     }
 772 
 773     /** Attribute a type argument list, returning a list of types.
 774      *  Caller is responsible for calling checkRefTypes.
 775      */
 776     List<Type> attribAnyTypes(List<JCExpression> trees, Env<AttrContext> env) {
 777         ListBuffer<Type> argtypes = new ListBuffer<>();
 778         for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail)
 779             argtypes.append(attribType(l.head, env));
 780         return argtypes.toList();
 781     }
 782 
 783     /** Attribute a type argument list, returning a list of types.
 784      *  Check that all the types are references.
 785      */
 786     List<Type> attribTypes(List<JCExpression> trees, Env<AttrContext> env) {
 787         List<Type> types = attribAnyTypes(trees, env);
 788         return chk.checkRefTypes(trees, types);
 789     }
 790 
 791     /**
 792      * Attribute type variables (of generic classes or methods).
 793      * Compound types are attributed later in attribBounds.
 794      * @param typarams the type variables to enter
 795      * @param env      the current environment
 796      */
 797     void attribTypeVariables(List<JCTypeParameter> typarams, Env<AttrContext> env, boolean checkCyclic) {
 798         for (JCTypeParameter tvar : typarams) {
 799             TypeVar a = (TypeVar)tvar.type;
 800             a.tsym.flags_field |= UNATTRIBUTED;
 801             a.setUpperBound(Type.noType);
 802             if (!tvar.bounds.isEmpty()) {
 803                 List<Type> bounds = List.of(attribType(tvar.bounds.head, env));
 804                 for (JCExpression bound : tvar.bounds.tail)
 805                     bounds = bounds.prepend(attribType(bound, env));
 806                 types.setBounds(a, bounds.reverse());
 807             } else {
 808                 // if no bounds are given, assume a single bound of
 809                 // java.lang.Object.
 810                 types.setBounds(a, List.of(syms.objectType));
 811             }
 812             a.tsym.flags_field &= ~UNATTRIBUTED;
 813         }
 814         if (checkCyclic) {
 815             for (JCTypeParameter tvar : typarams) {
 816                 chk.checkNonCyclic(tvar.pos(), (TypeVar)tvar.type);
 817             }
 818         }
 819     }
 820 
 821     /**
 822      * Attribute the type references in a list of annotations.
 823      */
 824     void attribAnnotationTypes(List<JCAnnotation> annotations,
 825                                Env<AttrContext> env) {
 826         for (List<JCAnnotation> al = annotations; al.nonEmpty(); al = al.tail) {
 827             JCAnnotation a = al.head;
 828             attribType(a.annotationType, env);
 829         }
 830     }
 831 
 832     /**
 833      * Attribute a "lazy constant value".
 834      *  @param env         The env for the const value
 835      *  @param variable    The initializer for the const value
 836      *  @param type        The expected type, or null
 837      *  @see VarSymbol#setLazyConstValue
 838      */
 839     public Object attribLazyConstantValue(Env<AttrContext> env,
 840                                       JCVariableDecl variable,
 841                                       Type type) {
 842 
 843         DiagnosticPosition prevLintPos
 844                 = deferredLintHandler.setPos(variable.pos());
 845 
 846         final JavaFileObject prevSource = log.useSource(env.toplevel.sourcefile);
 847         try {
 848             Type itype = attribExpr(variable.init, env, type);
 849             if (variable.isImplicitlyTyped()) {
 850                 //fixup local variable type
 851                 type = variable.type = variable.sym.type = chk.checkLocalVarType(variable, itype, variable.name);
 852             }
 853             if (itype.constValue() != null) {
 854                 return coerce(itype, type).constValue();
 855             } else {
 856                 return null;
 857             }
 858         } finally {
 859             log.useSource(prevSource);
 860             deferredLintHandler.setPos(prevLintPos);
 861         }
 862     }
 863 
 864     /** Attribute type reference in an `extends' or `implements' clause.
 865      *  Supertypes of anonymous inner classes are usually already attributed.
 866      *
 867      *  @param tree              The tree making up the type reference.
 868      *  @param env               The environment current at the reference.
 869      *  @param classExpected     true if only a class is expected here.
 870      *  @param interfaceExpected true if only an interface is expected here.
 871      */
 872     Type attribBase(JCTree tree,
 873                     Env<AttrContext> env,
 874                     boolean classExpected,
 875                     boolean interfaceExpected,
 876                     boolean checkExtensible) {
 877         Type t = tree.type != null ?
 878             tree.type :
 879             attribType(tree, env);
 880         try {
 881             return checkBase(t, tree, env, classExpected, interfaceExpected, checkExtensible);
 882         } catch (CompletionFailure ex) {
 883             chk.completionError(tree.pos(), ex);
 884             return t;
 885         }
 886     }
 887     Type checkBase(Type t,
 888                    JCTree tree,
 889                    Env<AttrContext> env,
 890                    boolean classExpected,
 891                    boolean interfaceExpected,
 892                    boolean checkExtensible) {
 893         final DiagnosticPosition pos = tree.hasTag(TYPEAPPLY) ?
 894                 (((JCTypeApply) tree).clazz).pos() : tree.pos();
 895         if (t.tsym.isAnonymous()) {
 896             log.error(pos, Errors.CantInheritFromAnon);
 897             return types.createErrorType(t);
 898         }
 899         if (t.isErroneous())
 900             return t;
 901         if (t.hasTag(TYPEVAR) && !classExpected && !interfaceExpected) {
 902             // check that type variable is already visible
 903             if (t.getUpperBound() == null) {
 904                 log.error(pos, Errors.IllegalForwardRef);
 905                 return types.createErrorType(t);
 906             }
 907         } else {
 908             t = chk.checkClassType(pos, t, checkExtensible);
 909         }
 910         if (interfaceExpected && (t.tsym.flags() & INTERFACE) == 0) {
 911             log.error(pos, Errors.IntfExpectedHere);
 912             // return errType is necessary since otherwise there might
 913             // be undetected cycles which cause attribution to loop
 914             return types.createErrorType(t);
 915         } else if (checkExtensible &&
 916                    classExpected &&
 917                    (t.tsym.flags() & INTERFACE) != 0) {
 918             log.error(pos, Errors.NoIntfExpectedHere);
 919             return types.createErrorType(t);
 920         }
 921         if (checkExtensible &&
 922             ((t.tsym.flags() & FINAL) != 0)) {
 923             log.error(pos,
 924                       Errors.CantInheritFromFinal(t.tsym));
 925         }
 926         chk.checkNonCyclic(pos, t);
 927         return t;
 928     }
 929 
 930     Type attribIdentAsEnumType(Env<AttrContext> env, JCIdent id) {
 931         Assert.check((env.enclClass.sym.flags() & ENUM) != 0);
 932         id.type = env.info.scope.owner.enclClass().type;
 933         id.sym = env.info.scope.owner.enclClass();
 934         return id.type;
 935     }
 936 
 937     public void visitClassDef(JCClassDecl tree) {
 938         Optional<ArgumentAttr.LocalCacheContext> localCacheContext =
 939                 Optional.ofNullable(env.info.attributionMode.isSpeculative ?
 940                         argumentAttr.withLocalCacheContext() : null);
 941         try {
 942             // Local and anonymous classes have not been entered yet, so we need to
 943             // do it now.
 944             if (env.info.scope.owner.kind.matches(KindSelector.VAL_MTH)) {
 945                 enter.classEnter(tree, env);
 946             } else {
 947                 // If this class declaration is part of a class level annotation,
 948                 // as in @MyAnno(new Object() {}) class MyClass {}, enter it in
 949                 // order to simplify later steps and allow for sensible error
 950                 // messages.
 951                 if (env.tree.hasTag(NEWCLASS) && TreeInfo.isInAnnotation(env, tree))
 952                     enter.classEnter(tree, env);
 953             }
 954 
 955             ClassSymbol c = tree.sym;
 956             if (c == null) {
 957                 // exit in case something drastic went wrong during enter.
 958                 result = null;
 959             } else {
 960                 // make sure class has been completed:
 961                 c.complete();
 962 
 963                 // If this class appears as an anonymous class
 964                 // in a superclass constructor call
 965                 // disable implicit outer instance from being passed.
 966                 // (This would be an illegal access to "this before super").
 967                 if (env.info.isSelfCall &&
 968                         env.tree.hasTag(NEWCLASS)) {
 969                     c.flags_field |= NOOUTERTHIS;
 970                 }
 971                 attribClass(tree.pos(), c);
 972                 result = tree.type = c.type;
 973             }
 974         } finally {
 975             localCacheContext.ifPresent(LocalCacheContext::leave);
 976         }
 977     }
 978 
 979     public void visitMethodDef(JCMethodDecl tree) {
 980         MethodSymbol m = tree.sym;
 981         boolean isDefaultMethod = (m.flags() & DEFAULT) != 0;
 982 
 983         Lint lint = env.info.lint.augment(m);
 984         Lint prevLint = chk.setLint(lint);
 985         MethodSymbol prevMethod = chk.setMethod(m);
 986         try {
 987             deferredLintHandler.flush(tree.pos());
 988             chk.checkDeprecatedAnnotation(tree.pos(), m);
 989 
 990 
 991             // Create a new environment with local scope
 992             // for attributing the method.
 993             Env<AttrContext> localEnv = memberEnter.methodEnv(tree, env);
 994             localEnv.info.lint = lint;
 995 
 996             attribStats(tree.typarams, localEnv);
 997 
 998             // If we override any other methods, check that we do so properly.
 999             // JLS ???
1000             if (m.isStatic()) {
1001                 chk.checkHideClashes(tree.pos(), env.enclClass.type, m);
1002             } else {
1003                 chk.checkOverrideClashes(tree.pos(), env.enclClass.type, m);
1004             }
1005             chk.checkOverride(env, tree, m);
1006 
1007             if (isDefaultMethod && types.overridesObjectMethod(m.enclClass(), m)) {
1008                 log.error(tree, Errors.DefaultOverridesObjectMember(m.name, Kinds.kindName(m.location()), m.location()));
1009             }
1010 
1011             // Enter all type parameters into the local method scope.
1012             for (List<JCTypeParameter> l = tree.typarams; l.nonEmpty(); l = l.tail)
1013                 localEnv.info.scope.enterIfAbsent(l.head.type.tsym);
1014 
1015             ClassSymbol owner = env.enclClass.sym;
1016             if ((owner.flags() & ANNOTATION) != 0 &&
1017                     (tree.params.nonEmpty() ||
1018                     tree.recvparam != null))
1019                 log.error(tree.params.nonEmpty() ?
1020                         tree.params.head.pos() :
1021                         tree.recvparam.pos(),
1022                         Errors.IntfAnnotationMembersCantHaveParams);
1023 
1024             // Attribute all value parameters.
1025             for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
1026                 attribStat(l.head, localEnv);
1027             }
1028 
1029             chk.checkVarargsMethodDecl(localEnv, tree);
1030 
1031             // Check that type parameters are well-formed.
1032             chk.validate(tree.typarams, localEnv);
1033 
1034             // Check that result type is well-formed.
1035             if (tree.restype != null && !tree.restype.type.hasTag(VOID))
1036                 chk.validate(tree.restype, localEnv);
1037 
1038             // Check that receiver type is well-formed.
1039             if (tree.recvparam != null) {
1040                 // Use a new environment to check the receiver parameter.
1041                 // Otherwise I get "might not have been initialized" errors.
1042                 // Is there a better way?
1043                 Env<AttrContext> newEnv = memberEnter.methodEnv(tree, env);
1044                 attribType(tree.recvparam, newEnv);
1045                 chk.validate(tree.recvparam, newEnv);
1046             }
1047 
1048             if (env.enclClass.sym.isRecord() && tree.sym.owner.kind == TYP) {
1049                 // lets find if this method is an accessor
1050                 Optional<? extends RecordComponent> recordComponent = env.enclClass.sym.getRecordComponents().stream()
1051                         .filter(rc -> rc.accessor == tree.sym && (rc.accessor.flags_field & GENERATED_MEMBER) == 0).findFirst();
1052                 if (recordComponent.isPresent()) {
1053                     // the method is a user defined accessor lets check that everything is fine
1054                     if (!tree.sym.isPublic()) {
1055                         log.error(tree, Errors.InvalidAccessorMethodInRecord(env.enclClass.sym, Fragments.MethodMustBePublic));
1056                     }
1057                     if (!types.isSameType(tree.sym.type.getReturnType(), recordComponent.get().type)) {
1058                         log.error(tree, Errors.InvalidAccessorMethodInRecord(env.enclClass.sym,
1059                                 Fragments.AccessorReturnTypeDoesntMatch(tree.sym, recordComponent.get())));
1060                     }
1061                     if (tree.sym.type.asMethodType().thrown != null && !tree.sym.type.asMethodType().thrown.isEmpty()) {
1062                         log.error(tree,
1063                                 Errors.InvalidAccessorMethodInRecord(env.enclClass.sym, Fragments.AccessorMethodCantThrowException));
1064                     }
1065                     if (!tree.typarams.isEmpty()) {
1066                         log.error(tree,
1067                                 Errors.InvalidAccessorMethodInRecord(env.enclClass.sym, Fragments.AccessorMethodMustNotBeGeneric));
1068                     }
1069                     if (tree.sym.isStatic()) {
1070                         log.error(tree,
1071                                 Errors.InvalidAccessorMethodInRecord(env.enclClass.sym, Fragments.AccessorMethodMustNotBeStatic));
1072                     }
1073                 }
1074 
1075                 if (tree.name == names.init) {
1076                     // if this a constructor other than the canonical one
1077                     if ((tree.sym.flags_field & RECORD) == 0) {
1078                         JCMethodInvocation app = TreeInfo.firstConstructorCall(tree);
1079                         if (app == null ||
1080                                 TreeInfo.name(app.meth) != names._this ||
1081                                 !checkFirstConstructorStat(app, tree, false)) {
1082                             log.error(tree, Errors.FirstStatementMustBeCallToAnotherConstructor(env.enclClass.sym));
1083                         }
1084                     } else {
1085                         // but if it is the canonical:
1086 
1087                         /* if user generated, then it shouldn't:
1088                          *     - have an accessibility stricter than that of the record type
1089                          *     - explicitly invoke any other constructor
1090                          */
1091                         if ((tree.sym.flags_field & GENERATEDCONSTR) == 0) {
1092                             if (Check.protection(m.flags()) > Check.protection(env.enclClass.sym.flags())) {
1093                                 log.error(tree,
1094                                         (env.enclClass.sym.flags() & AccessFlags) == 0 ?
1095                                             Errors.InvalidCanonicalConstructorInRecord(
1096                                                 Fragments.Canonical,
1097                                                 env.enclClass.sym.name,
1098                                                 Fragments.CanonicalMustNotHaveStrongerAccess("package")
1099                                             ) :
1100                                             Errors.InvalidCanonicalConstructorInRecord(
1101                                                     Fragments.Canonical,
1102                                                     env.enclClass.sym.name,
1103                                                     Fragments.CanonicalMustNotHaveStrongerAccess(asFlagSet(env.enclClass.sym.flags() & AccessFlags))
1104                                             )
1105                                 );
1106                             }
1107 
1108                             JCMethodInvocation app = TreeInfo.firstConstructorCall(tree);
1109                             if (app != null &&
1110                                     (TreeInfo.name(app.meth) == names._this ||
1111                                             TreeInfo.name(app.meth) == names._super) &&
1112                                     checkFirstConstructorStat(app, tree, false)) {
1113                                 log.error(tree, Errors.InvalidCanonicalConstructorInRecord(
1114                                         Fragments.Canonical, env.enclClass.sym.name,
1115                                         Fragments.CanonicalMustNotContainExplicitConstructorInvocation));
1116                             }
1117                         }
1118 
1119                         // also we want to check that no type variables have been defined
1120                         if (!tree.typarams.isEmpty()) {
1121                             log.error(tree, Errors.InvalidCanonicalConstructorInRecord(
1122                                     Fragments.Canonical, env.enclClass.sym.name, Fragments.CanonicalMustNotDeclareTypeVariables));
1123                         }
1124 
1125                         /* and now we need to check that the constructor's arguments are exactly the same as those of the
1126                          * record components
1127                          */
1128                         List<? extends RecordComponent> recordComponents = env.enclClass.sym.getRecordComponents();
1129                         List<Type> recordFieldTypes = TreeInfo.recordFields(env.enclClass).map(vd -> vd.sym.type);
1130                         for (JCVariableDecl param: tree.params) {
1131                             boolean paramIsVarArgs = (param.sym.flags_field & VARARGS) != 0;
1132                             if (!types.isSameType(param.type, recordFieldTypes.head) ||
1133                                     (recordComponents.head.isVarargs() != paramIsVarArgs)) {
1134                                 log.error(param, Errors.InvalidCanonicalConstructorInRecord(
1135                                         Fragments.Canonical, env.enclClass.sym.name,
1136                                         Fragments.TypeMustBeIdenticalToCorrespondingRecordComponentType));
1137                             }
1138                             recordComponents = recordComponents.tail;
1139                             recordFieldTypes = recordFieldTypes.tail;
1140                         }
1141                     }
1142                 }
1143             }
1144 
1145             // annotation method checks
1146             if ((owner.flags() & ANNOTATION) != 0) {
1147                 // annotation method cannot have throws clause
1148                 if (tree.thrown.nonEmpty()) {
1149                     log.error(tree.thrown.head.pos(),
1150                               Errors.ThrowsNotAllowedInIntfAnnotation);
1151                 }
1152                 // annotation method cannot declare type-parameters
1153                 if (tree.typarams.nonEmpty()) {
1154                     log.error(tree.typarams.head.pos(),
1155                               Errors.IntfAnnotationMembersCantHaveTypeParams);
1156                 }
1157                 // validate annotation method's return type (could be an annotation type)
1158                 chk.validateAnnotationType(tree.restype);
1159                 // ensure that annotation method does not clash with members of Object/Annotation
1160                 chk.validateAnnotationMethod(tree.pos(), m);
1161             }
1162 
1163             for (List<JCExpression> l = tree.thrown; l.nonEmpty(); l = l.tail)
1164                 chk.checkType(l.head.pos(), l.head.type, syms.throwableType);
1165 
1166             if (tree.body == null) {
1167                 // Empty bodies are only allowed for
1168                 // abstract, native, or interface methods, or for methods
1169                 // in a retrofit signature class.
1170                 if (tree.defaultValue != null) {
1171                     if ((owner.flags() & ANNOTATION) == 0)
1172                         log.error(tree.pos(),
1173                                   Errors.DefaultAllowedInIntfAnnotationMember);
1174                 }
1175                 if (isDefaultMethod || (tree.sym.flags() & (ABSTRACT | NATIVE)) == 0)
1176                     log.error(tree.pos(), Errors.MissingMethBodyOrDeclAbstract);
1177             } else {
1178                 if ((tree.sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
1179                     if ((owner.flags() & INTERFACE) != 0) {
1180                         log.error(tree.body.pos(), Errors.IntfMethCantHaveBody);
1181                     } else {
1182                         log.error(tree.pos(), Errors.AbstractMethCantHaveBody);
1183                     }
1184                 } else if ((tree.mods.flags & NATIVE) != 0) {
1185                     log.error(tree.pos(), Errors.NativeMethCantHaveBody);
1186                 }
1187                 // Add an implicit super() call unless an explicit call to
1188                 // super(...) or this(...) is given
1189                 // or we are compiling class java.lang.Object.
1190                 if (tree.name == names.init && owner.type != syms.objectType) {
1191                     JCBlock body = tree.body;
1192                     if (body.stats.isEmpty() ||
1193                             TreeInfo.getConstructorInvocationName(body.stats, names) == names.empty) {
1194                         JCStatement supCall = make.at(body.pos).Exec(make.Apply(List.nil(),
1195                                 make.Ident(names._super), make.Idents(List.nil())));
1196                         body.stats = body.stats.prepend(supCall);
1197                     } else if ((env.enclClass.sym.flags() & ENUM) != 0 &&
1198                             (tree.mods.flags & GENERATEDCONSTR) == 0 &&
1199                             TreeInfo.isSuperCall(body.stats.head)) {
1200                         // enum constructors are not allowed to call super
1201                         // directly, so make sure there aren't any super calls
1202                         // in enum constructors, except in the compiler
1203                         // generated one.
1204                         log.error(tree.body.stats.head.pos(),
1205                                   Errors.CallToSuperNotAllowedInEnumCtor(env.enclClass.sym));
1206                     }
1207                     if (env.enclClass.sym.isRecord() && (tree.sym.flags_field & RECORD) != 0) { // we are seeing the canonical constructor
1208                         List<Name> recordComponentNames = TreeInfo.recordFields(env.enclClass).map(vd -> vd.sym.name);
1209                         List<Name> initParamNames = tree.sym.params.map(p -> p.name);
1210                         if (!initParamNames.equals(recordComponentNames)) {
1211                             log.error(tree, Errors.InvalidCanonicalConstructorInRecord(
1212                                     Fragments.Canonical, env.enclClass.sym.name, Fragments.CanonicalWithNameMismatch));
1213                         }
1214                         if (tree.sym.type.asMethodType().thrown != null && !tree.sym.type.asMethodType().thrown.isEmpty()) {
1215                             log.error(tree,
1216                                     Errors.InvalidCanonicalConstructorInRecord(
1217                                             TreeInfo.isCompactConstructor(tree) ? Fragments.Compact : Fragments.Canonical,
1218                                             env.enclClass.sym.name,
1219                                             Fragments.ThrowsClauseNotAllowedForCanonicalConstructor(
1220                                                     TreeInfo.isCompactConstructor(tree) ? Fragments.Compact : Fragments.Canonical)));
1221                         }
1222                     }
1223                 }
1224 
1225                 // Attribute all type annotations in the body
1226                 annotate.queueScanTreeAndTypeAnnotate(tree.body, localEnv, m, null);
1227                 annotate.flush();
1228 
1229                 // Attribute method body.
1230                 attribStat(tree.body, localEnv);
1231             }
1232 
1233             localEnv.info.scope.leave();
1234             result = tree.type = m.type;
1235         } finally {
1236             chk.setLint(prevLint);
1237             chk.setMethod(prevMethod);
1238         }
1239     }
1240 
1241     public void visitVarDef(JCVariableDecl tree) {
1242         // Local variables have not been entered yet, so we need to do it now:
1243         if (env.info.scope.owner.kind == MTH || env.info.scope.owner.kind == VAR) {
1244             if (tree.sym != null) {
1245                 // parameters have already been entered
1246                 env.info.scope.enter(tree.sym);
1247             } else {
1248                 if (tree.isImplicitlyTyped() && (tree.getModifiers().flags & PARAMETER) == 0) {
1249                     if (tree.init == null) {
1250                         //cannot use 'var' without initializer
1251                         log.error(tree, Errors.CantInferLocalVarType(tree.name, Fragments.LocalMissingInit));
1252                         tree.vartype = make.Erroneous();
1253                     } else {
1254                         Fragment msg = canInferLocalVarType(tree);
1255                         if (msg != null) {
1256                             //cannot use 'var' with initializer which require an explicit target
1257                             //(e.g. lambda, method reference, array initializer).
1258                             log.error(tree, Errors.CantInferLocalVarType(tree.name, msg));
1259                             tree.vartype = make.Erroneous();
1260                         }
1261                     }
1262                 }
1263                 try {
1264                     annotate.blockAnnotations();
1265                     memberEnter.memberEnter(tree, env);
1266                 } finally {
1267                     annotate.unblockAnnotations();
1268                 }
1269             }
1270         } else {
1271             if (tree.init != null) {
1272                 // Field initializer expression need to be entered.
1273                 annotate.queueScanTreeAndTypeAnnotate(tree.init, env, tree.sym, tree.pos());
1274                 annotate.flush();
1275             }
1276         }
1277 
1278         VarSymbol v = tree.sym;
1279         Lint lint = env.info.lint.augment(v);
1280         Lint prevLint = chk.setLint(lint);
1281 
1282         // Check that the variable's declared type is well-formed.
1283         boolean isImplicitLambdaParameter = env.tree.hasTag(LAMBDA) &&
1284                 ((JCLambda)env.tree).paramKind == JCLambda.ParameterKind.IMPLICIT &&
1285                 (tree.sym.flags() & PARAMETER) != 0;
1286         chk.validate(tree.vartype, env, !isImplicitLambdaParameter && !tree.isImplicitlyTyped());
1287 
1288         try {
1289             v.getConstValue(); // ensure compile-time constant initializer is evaluated
1290             deferredLintHandler.flush(tree.pos());
1291             chk.checkDeprecatedAnnotation(tree.pos(), v);
1292 
1293             if (tree.init != null) {
1294                 if ((v.flags_field & FINAL) == 0 ||
1295                     !memberEnter.needsLazyConstValue(tree.init)) {
1296                     // Not a compile-time constant
1297                     // Attribute initializer in a new environment
1298                     // with the declared variable as owner.
1299                     // Check that initializer conforms to variable's declared type.
1300                     Env<AttrContext> initEnv = memberEnter.initEnv(tree, env);
1301                     initEnv.info.lint = lint;
1302                     // In order to catch self-references, we set the variable's
1303                     // declaration position to maximal possible value, effectively
1304                     // marking the variable as undefined.
1305                     initEnv.info.enclVar = v;
1306                     attribExpr(tree.init, initEnv, v.type);
1307                     if (tree.isImplicitlyTyped()) {
1308                         //fixup local variable type
1309                         v.type = chk.checkLocalVarType(tree, tree.init.type, tree.name);
1310                     }
1311                 }
1312                 if (tree.isImplicitlyTyped()) {
1313                     setSyntheticVariableType(tree, v.type);
1314                 }
1315             }
1316             result = tree.type = v.type;
1317             if (env.enclClass.sym.isRecord() && tree.sym.owner.kind == TYP && !v.isStatic()) {
1318                 if (isNonArgsMethodInObject(v.name)) {
1319                     log.error(tree, Errors.IllegalRecordComponentName(v));
1320                 }
1321             }
1322         }
1323         finally {
1324             chk.setLint(prevLint);
1325         }
1326     }
1327 
1328     private boolean isNonArgsMethodInObject(Name name) {
1329         for (Symbol s : syms.objectType.tsym.members().getSymbolsByName(name, s -> s.kind == MTH)) {
1330             if (s.type.getParameterTypes().isEmpty()) {
1331                 return true;
1332             }
1333         }
1334         return false;
1335     }
1336 
1337     Fragment canInferLocalVarType(JCVariableDecl tree) {
1338         LocalInitScanner lis = new LocalInitScanner();
1339         lis.scan(tree.init);
1340         return lis.badInferenceMsg;
1341     }
1342 
1343     static class LocalInitScanner extends TreeScanner {
1344         Fragment badInferenceMsg = null;
1345         boolean needsTarget = true;
1346 
1347         @Override
1348         public void visitNewArray(JCNewArray tree) {
1349             if (tree.elemtype == null && needsTarget) {
1350                 badInferenceMsg = Fragments.LocalArrayMissingTarget;
1351             }
1352         }
1353 
1354         @Override
1355         public void visitLambda(JCLambda tree) {
1356             if (needsTarget) {
1357                 badInferenceMsg = Fragments.LocalLambdaMissingTarget;
1358             }
1359         }
1360 
1361         @Override
1362         public void visitTypeCast(JCTypeCast tree) {
1363             boolean prevNeedsTarget = needsTarget;
1364             try {
1365                 needsTarget = false;
1366                 super.visitTypeCast(tree);
1367             } finally {
1368                 needsTarget = prevNeedsTarget;
1369             }
1370         }
1371 
1372         @Override
1373         public void visitReference(JCMemberReference tree) {
1374             if (needsTarget) {
1375                 badInferenceMsg = Fragments.LocalMrefMissingTarget;
1376             }
1377         }
1378 
1379         @Override
1380         public void visitNewClass(JCNewClass tree) {
1381             boolean prevNeedsTarget = needsTarget;
1382             try {
1383                 needsTarget = false;
1384                 super.visitNewClass(tree);
1385             } finally {
1386                 needsTarget = prevNeedsTarget;
1387             }
1388         }
1389 
1390         @Override
1391         public void visitApply(JCMethodInvocation tree) {
1392             boolean prevNeedsTarget = needsTarget;
1393             try {
1394                 needsTarget = false;
1395                 super.visitApply(tree);
1396             } finally {
1397                 needsTarget = prevNeedsTarget;
1398             }
1399         }
1400     }
1401 
1402     public void visitSkip(JCSkip tree) {
1403         result = null;
1404     }
1405 
1406     public void visitBlock(JCBlock tree) {
1407         if (env.info.scope.owner.kind == TYP || env.info.scope.owner.kind == ERR) {
1408             // Block is a static or instance initializer;
1409             // let the owner of the environment be a freshly
1410             // created BLOCK-method.
1411             Symbol fakeOwner =
1412                 new MethodSymbol(tree.flags | BLOCK |
1413                     env.info.scope.owner.flags() & STRICTFP, names.empty, null,
1414                     env.info.scope.owner);
1415             final Env<AttrContext> localEnv =
1416                 env.dup(tree, env.info.dup(env.info.scope.dupUnshared(fakeOwner)));
1417 
1418             if ((tree.flags & STATIC) != 0) localEnv.info.staticLevel++;
1419             // Attribute all type annotations in the block
1420             annotate.queueScanTreeAndTypeAnnotate(tree, localEnv, localEnv.info.scope.owner, null);
1421             annotate.flush();
1422             attribStats(tree.stats, localEnv);
1423 
1424             {
1425                 // Store init and clinit type annotations with the ClassSymbol
1426                 // to allow output in Gen.normalizeDefs.
1427                 ClassSymbol cs = (ClassSymbol)env.info.scope.owner;
1428                 List<Attribute.TypeCompound> tas = localEnv.info.scope.owner.getRawTypeAttributes();
1429                 if ((tree.flags & STATIC) != 0) {
1430                     cs.appendClassInitTypeAttributes(tas);
1431                 } else {
1432                     cs.appendInitTypeAttributes(tas);
1433                 }
1434             }
1435         } else {
1436             // Create a new local environment with a local scope.
1437             Env<AttrContext> localEnv =
1438                 env.dup(tree, env.info.dup(env.info.scope.dup()));
1439             try {
1440                 attribStats(tree.stats, localEnv);
1441             } finally {
1442                 localEnv.info.scope.leave();
1443             }
1444         }
1445         result = null;
1446     }
1447 
1448     public void visitDoLoop(JCDoWhileLoop tree) {
1449         attribStat(tree.body, env.dup(tree));
1450         attribExpr(tree.cond, env, syms.booleanType);
1451         if (!breaksOutOf(tree, tree.body)) {
1452             //include condition's body when false after the while, if cannot get out of the loop
1453             MatchBindings condBindings = matchBindings;
1454             condBindings.bindingsWhenFalse.forEach(env.info.scope::enter);
1455             condBindings.bindingsWhenFalse.forEach(BindingSymbol::preserveBinding);
1456         }
1457         result = null;
1458     }
1459 
1460     public void visitWhileLoop(JCWhileLoop tree) {
1461         attribExpr(tree.cond, env, syms.booleanType);
1462         MatchBindings condBindings = matchBindings;
1463         // include condition's bindings when true in the body:
1464         Env<AttrContext> whileEnv = bindingEnv(env, condBindings.bindingsWhenTrue);
1465         try {
1466             attribStat(tree.body, whileEnv.dup(tree));
1467         } finally {
1468             whileEnv.info.scope.leave();
1469         }
1470         if (!breaksOutOf(tree, tree.body)) {
1471             //include condition's bindings when false after the while, if cannot get out of the loop
1472             condBindings.bindingsWhenFalse.forEach(env.info.scope::enter);
1473             condBindings.bindingsWhenFalse.forEach(BindingSymbol::preserveBinding);
1474         }
1475         result = null;
1476     }
1477 
1478     private boolean breaksOutOf(JCTree loop, JCTree body) {
1479         preFlow(body);
1480         return flow.breaksOutOf(env, loop, body, make);
1481     }
1482 
1483     public void visitForLoop(JCForLoop tree) {
1484         Env<AttrContext> loopEnv =
1485             env.dup(env.tree, env.info.dup(env.info.scope.dup()));
1486         MatchBindings condBindings = MatchBindingsComputer.EMPTY;
1487         try {
1488             attribStats(tree.init, loopEnv);
1489             if (tree.cond != null) {
1490                 attribExpr(tree.cond, loopEnv, syms.booleanType);
1491                 // include condition's bindings when true in the body and step:
1492                 condBindings = matchBindings;
1493             }
1494             Env<AttrContext> bodyEnv = bindingEnv(loopEnv, condBindings.bindingsWhenTrue);
1495             try {
1496                 bodyEnv.tree = tree; // before, we were not in loop!
1497                 attribStats(tree.step, bodyEnv);
1498                 attribStat(tree.body, bodyEnv);
1499             } finally {
1500                 bodyEnv.info.scope.leave();
1501             }
1502             result = null;
1503         }
1504         finally {
1505             loopEnv.info.scope.leave();
1506         }
1507         if (!breaksOutOf(tree, tree.body)) {
1508             //include condition's body when false after the while, if cannot get out of the loop
1509             condBindings.bindingsWhenFalse.forEach(env.info.scope::enter);
1510             condBindings.bindingsWhenFalse.forEach(BindingSymbol::preserveBinding);
1511         }
1512     }
1513 
1514     public void visitForeachLoop(JCEnhancedForLoop tree) {
1515         Env<AttrContext> loopEnv =
1516             env.dup(env.tree, env.info.dup(env.info.scope.dup()));
1517 
1518         try {
1519             //the Formal Parameter of a for-each loop is not in the scope when
1520             //attributing the for-each expression; we mimic this by attributing
1521             //the for-each expression first (against original scope).
1522             Type exprType = types.cvarUpperBound(attribExpr(tree.expr, loopEnv));
1523             chk.checkNonVoid(tree.pos(), exprType);
1524             tree.elementType = types.elemtype(exprType); // perhaps expr is an array?
1525             if (tree.elementType == null) {
1526                 // or perhaps expr implements Iterable<T>?
1527                 Type base = types.asSuper(exprType, syms.iterableType.tsym);
1528                 if (base == null) {
1529                     log.error(tree.expr.pos(),
1530                               Errors.ForeachNotApplicableToType(exprType,
1531                                                                 Fragments.TypeReqArrayOrIterable));
1532                     tree.elementType = types.createErrorType(exprType);
1533                 } else {
1534                     List<Type> iterableParams = base.allparams();
1535                     tree.elementType = iterableParams.isEmpty()
1536                         ? syms.objectType
1537                         : types.wildUpperBound(iterableParams.head);
1538 
1539                     // Check the return type of the method iterator().
1540                     // This is the bare minimum we need to verify to make sure code generation doesn't crash.
1541                     Symbol iterSymbol = rs.resolveInternalMethod(tree.pos(),
1542                             loopEnv, types.skipTypeVars(exprType, false), names.iterator, List.nil(), List.nil());
1543                     if (types.asSuper(iterSymbol.type.getReturnType(), syms.iteratorType.tsym) == null) {
1544                         log.error(tree.pos(),
1545                                 Errors.ForeachNotApplicableToType(exprType, Fragments.TypeReqArrayOrIterable));
1546                     }
1547                 }
1548             }
1549             if (tree.varOrRecordPattern instanceof JCVariableDecl jcVariableDecl) {
1550                 if (jcVariableDecl.isImplicitlyTyped()) {
1551                     Type inferredType = chk.checkLocalVarType(jcVariableDecl, tree.elementType, jcVariableDecl.name);
1552                     setSyntheticVariableType(jcVariableDecl, inferredType);
1553                 }
1554                 attribStat(jcVariableDecl, loopEnv);
1555                 chk.checkType(tree.expr.pos(), tree.elementType, jcVariableDecl.sym.type);
1556 
1557                 loopEnv.tree = tree; // before, we were not in loop!
1558                 attribStat(tree.body, loopEnv);
1559             } else {
1560                 Assert.check(tree.getDeclarationKind() == EnhancedForLoopTree.DeclarationKind.PATTERN);
1561                 JCRecordPattern jcRecordPattern = (JCRecordPattern) tree.varOrRecordPattern;
1562 
1563                 attribExpr(jcRecordPattern, loopEnv, tree.elementType);
1564 
1565                 // for(<pattern> x : xs) { y }
1566                 // we include x's bindings when true in y
1567                 // we don't do anything with x's bindings when false
1568 
1569                 MatchBindings forWithRecordPatternBindings = matchBindings;
1570                 Env<AttrContext> recordPatternEnv = bindingEnv(loopEnv, forWithRecordPatternBindings.bindingsWhenTrue);
1571 
1572                 Type clazztype = jcRecordPattern.type;
1573 
1574                 checkCastablePattern(tree.expr.pos(), tree.elementType, clazztype);
1575 
1576                 recordPatternEnv.tree = tree; // before, we were not in loop!
1577                 try {
1578                     attribStat(tree.body, recordPatternEnv);
1579                 } finally {
1580                     recordPatternEnv.info.scope.leave();
1581                 }
1582             }
1583             result = null;
1584         }
1585         finally {
1586             loopEnv.info.scope.leave();
1587         }
1588     }
1589 
1590     public void visitLabelled(JCLabeledStatement tree) {
1591         // Check that label is not used in an enclosing statement
1592         Env<AttrContext> env1 = env;
1593         while (env1 != null && !env1.tree.hasTag(CLASSDEF)) {
1594             if (env1.tree.hasTag(LABELLED) &&
1595                 ((JCLabeledStatement) env1.tree).label == tree.label) {
1596                 log.error(tree.pos(),
1597                           Errors.LabelAlreadyInUse(tree.label));
1598                 break;
1599             }
1600             env1 = env1.next;
1601         }
1602 
1603         attribStat(tree.body, env.dup(tree));
1604         result = null;
1605     }
1606 
1607     public void visitSwitch(JCSwitch tree) {
1608         handleSwitch(tree, tree.selector, tree.cases, (c, caseEnv) -> {
1609             attribStats(c.stats, caseEnv);
1610         });
1611         result = null;
1612     }
1613 
1614     public void visitSwitchExpression(JCSwitchExpression tree) {
1615         tree.polyKind = (pt().hasTag(NONE) && pt() != Type.recoveryType && pt() != Infer.anyPoly) ?
1616                 PolyKind.STANDALONE : PolyKind.POLY;
1617 
1618         if (tree.polyKind == PolyKind.POLY && resultInfo.pt.hasTag(VOID)) {
1619             //this means we are returning a poly conditional from void-compatible lambda expression
1620             resultInfo.checkContext.report(tree, diags.fragment(Fragments.SwitchExpressionTargetCantBeVoid));
1621             result = tree.type = types.createErrorType(resultInfo.pt);
1622             return;
1623         }
1624 
1625         ResultInfo condInfo = tree.polyKind == PolyKind.STANDALONE ?
1626                 unknownExprInfo :
1627                 resultInfo.dup(switchExpressionContext(resultInfo.checkContext));
1628 
1629         ListBuffer<DiagnosticPosition> caseTypePositions = new ListBuffer<>();
1630         ListBuffer<Type> caseTypes = new ListBuffer<>();
1631 
1632         handleSwitch(tree, tree.selector, tree.cases, (c, caseEnv) -> {
1633             caseEnv.info.yieldResult = condInfo;
1634             attribStats(c.stats, caseEnv);
1635             new TreeScanner() {
1636                 @Override
1637                 public void visitYield(JCYield brk) {
1638                     if (brk.target == tree) {
1639                         caseTypePositions.append(brk.value != null ? brk.value.pos() : brk.pos());
1640                         caseTypes.append(brk.value != null ? brk.value.type : syms.errType);
1641                     }
1642                     super.visitYield(brk);
1643                 }
1644 
1645                 @Override public void visitClassDef(JCClassDecl tree) {}
1646                 @Override public void visitLambda(JCLambda tree) {}
1647             }.scan(c.stats);
1648         });
1649 
1650         if (tree.cases.isEmpty()) {
1651             log.error(tree.pos(),
1652                       Errors.SwitchExpressionEmpty);
1653         } else if (caseTypes.isEmpty()) {
1654             log.error(tree.pos(),
1655                       Errors.SwitchExpressionNoResultExpressions);
1656         }
1657 
1658         Type owntype = (tree.polyKind == PolyKind.STANDALONE) ? condType(caseTypePositions.toList(), caseTypes.toList()) : pt();
1659 
1660         result = tree.type = check(tree, owntype, KindSelector.VAL, resultInfo);
1661     }
1662     //where:
1663         CheckContext switchExpressionContext(CheckContext checkContext) {
1664             return new Check.NestedCheckContext(checkContext) {
1665                 //this will use enclosing check context to check compatibility of
1666                 //subexpression against target type; if we are in a method check context,
1667                 //depending on whether boxing is allowed, we could have incompatibilities
1668                 @Override
1669                 public void report(DiagnosticPosition pos, JCDiagnostic details) {
1670                     enclosingContext.report(pos, diags.fragment(Fragments.IncompatibleTypeInSwitchExpression(details)));
1671                 }
1672             };
1673         }
1674 
1675     private void handleSwitch(JCTree switchTree,
1676                               JCExpression selector,
1677                               List<JCCase> cases,
1678                               BiConsumer<JCCase, Env<AttrContext>> attribCase) {
1679         Type seltype = attribExpr(selector, env);
1680 
1681         Env<AttrContext> switchEnv =
1682             env.dup(switchTree, env.info.dup(env.info.scope.dup()));
1683 
1684         try {
1685             boolean enumSwitch = (seltype.tsym.flags() & Flags.ENUM) != 0;
1686             boolean stringSwitch = types.isSameType(seltype, syms.stringType);
1687             boolean errorEnumSwitch = TreeInfo.isErrorEnumSwitch(selector, cases);
1688             boolean patternSwitch;
1689             if (!enumSwitch && !stringSwitch && !errorEnumSwitch &&
1690                 !types.isAssignable(seltype, syms.intType)) {
1691                 preview.checkSourceLevel(selector.pos(), Feature.PATTERN_SWITCH);
1692                 patternSwitch = true;
1693             } else {
1694                 patternSwitch = cases.stream()
1695                                      .flatMap(c -> c.labels.stream())
1696                                      .anyMatch(l -> l.hasTag(PATTERNCASELABEL) ||
1697                                                     TreeInfo.isNullCaseLabel(l));
1698             }
1699 
1700             // Attribute all cases and
1701             // check that there are no duplicate case labels or default clauses.
1702             Set<Object> constants = new HashSet<>(); // The set of case constants.
1703             boolean hasDefault = false;           // Is there a default label?
1704             boolean hasUnconditionalPattern = false; // Is there a unconditional pattern?
1705             boolean lastPatternErroneous = false; // Has the last pattern erroneous type?
1706             boolean hasNullPattern = false;       // Is there a null pattern?
1707             CaseTree.CaseKind caseKind = null;
1708             boolean wasError = false;
1709             for (List<JCCase> l = cases; l.nonEmpty(); l = l.tail) {
1710                 JCCase c = l.head;
1711                 if (caseKind == null) {
1712                     caseKind = c.caseKind;
1713                 } else if (caseKind != c.caseKind && !wasError) {
1714                     log.error(c.pos(),
1715                               Errors.SwitchMixingCaseTypes);
1716                     wasError = true;
1717                 }
1718                 MatchBindings currentBindings = null;
1719                 boolean wasUnconditionalPattern = hasUnconditionalPattern;
1720                 for (JCCaseLabel label : c.labels) {
1721                     if (label instanceof JCConstantCaseLabel constLabel) {
1722                         JCExpression expr = constLabel.expr;
1723                         if (TreeInfo.isNull(expr)) {
1724                             preview.checkSourceLevel(expr.pos(), Feature.CASE_NULL);
1725                             if (hasNullPattern) {
1726                                 log.error(label.pos(), Errors.DuplicateCaseLabel);
1727                             }
1728                             hasNullPattern = true;
1729                             attribExpr(expr, switchEnv, seltype);
1730                             matchBindings = new MatchBindings(matchBindings.bindingsWhenTrue, matchBindings.bindingsWhenFalse, true);
1731                         } else if (enumSwitch) {
1732                             Symbol sym = enumConstant(expr, seltype);
1733                             if (sym == null) {
1734                                 log.error(expr.pos(), Errors.EnumLabelMustBeUnqualifiedEnum);
1735                             } else if (!constants.add(sym)) {
1736                                 log.error(label.pos(), Errors.DuplicateCaseLabel);
1737                             }
1738                         } else if (errorEnumSwitch) {
1739                             //error recovery: the selector is erroneous, and all the case labels
1740                             //are identifiers. This could be an enum switch - don't report resolve
1741                             //error for the case label:
1742                             var prevResolveHelper = rs.basicLogResolveHelper;
1743                             try {
1744                                 rs.basicLogResolveHelper = rs.silentLogResolveHelper;
1745                                 attribExpr(expr, switchEnv, seltype);
1746                             } finally {
1747                                 rs.basicLogResolveHelper = prevResolveHelper;
1748                             }
1749                         } else {
1750                             ResultInfo valTypInfo = new ResultInfo(KindSelector.VAL_TYP,
1751                                                                    !seltype.hasTag(ERROR) ? seltype
1752                                                                                           : Type.noType);
1753                             Type pattype = attribTree(expr, switchEnv, valTypInfo);
1754                             if (!pattype.hasTag(ERROR)) {
1755                                 if (pattype.constValue() == null) {
1756                                     Symbol s = TreeInfo.symbol(expr);
1757                                     if (s != null && s.kind == TYP && allowPatternSwitch) {
1758                                         log.error(expr.pos(),
1759                                                   Errors.PatternExpected);
1760                                     } else {
1761                                         log.error(expr.pos(),
1762                                                   (stringSwitch ? Errors.StringConstReq : Errors.ConstExprReq));
1763                                     }
1764                                 } else if (!stringSwitch && !types.isAssignable(seltype, syms.intType)) {
1765                                     log.error(label.pos(), Errors.ConstantLabelNotCompatible(pattype, seltype));
1766                                 } else if (!constants.add(pattype.constValue())) {
1767                                     log.error(c.pos(), Errors.DuplicateCaseLabel);
1768                                 }
1769                             }
1770                         }
1771                     } else if (label instanceof JCDefaultCaseLabel def) {
1772                         if (hasDefault) {
1773                             log.error(label.pos(), Errors.DuplicateDefaultLabel);
1774                         } else if (hasUnconditionalPattern) {
1775                             log.error(label.pos(), Errors.UnconditionalPatternAndDefault);
1776                         }
1777                         hasDefault = true;
1778                         matchBindings = MatchBindingsComputer.EMPTY;
1779                     } else if (label instanceof JCPatternCaseLabel patternlabel) {
1780                         //pattern
1781                         JCPattern pat = patternlabel.pat;
1782                         attribExpr(pat, switchEnv, seltype);
1783                         Type primaryType = TreeInfo.primaryPatternType(pat);
1784                         if (!primaryType.hasTag(TYPEVAR)) {
1785                             primaryType = chk.checkClassOrArrayType(pat.pos(), primaryType);
1786                         }
1787                         checkCastablePattern(pat.pos(), seltype, primaryType);
1788                         Type patternType = types.erasure(primaryType);
1789                         JCExpression guard = patternlabel.guard;
1790                         if (guard != null) {
1791                             MatchBindings afterPattern = matchBindings;
1792                             Env<AttrContext> bodyEnv = bindingEnv(switchEnv, matchBindings.bindingsWhenTrue);
1793                             try {
1794                                 attribExpr(guard, bodyEnv, syms.booleanType);
1795                             } finally {
1796                                 bodyEnv.info.scope.leave();
1797                             }
1798                             matchBindings = matchBindingsComputer.caseGuard(c, afterPattern, matchBindings);
1799 
1800                             if (TreeInfo.isBooleanWithValue(guard, 0)) {
1801                                 log.error(guard.pos(), Errors.GuardHasConstantExpressionFalse);
1802                             }
1803                         }
1804                         boolean unguarded = TreeInfo.unguardedCaseLabel(label) && !pat.hasTag(RECORDPATTERN);
1805                         boolean unconditional =
1806                                 unguarded &&
1807                                 !patternType.isErroneous() &&
1808                                 types.isSubtype(types.boxedTypeOrType(types.erasure(seltype)),
1809                                                 patternType);
1810                         if (unconditional) {
1811                             if (hasUnconditionalPattern) {
1812                                 log.error(pat.pos(), Errors.DuplicateUnconditionalPattern);
1813                             } else if (hasDefault) {
1814                                 log.error(pat.pos(), Errors.UnconditionalPatternAndDefault);
1815                             }
1816                             hasUnconditionalPattern = true;
1817                         }
1818                         lastPatternErroneous = patternType.isErroneous();
1819                     } else {
1820                         Assert.error();
1821                     }
1822                     currentBindings = matchBindingsComputer.switchCase(label, currentBindings, matchBindings);
1823                 }
1824 
1825                 Env<AttrContext> caseEnv =
1826                         bindingEnv(switchEnv, c, currentBindings.bindingsWhenTrue);
1827                 try {
1828                     attribCase.accept(c, caseEnv);
1829                 } finally {
1830                     caseEnv.info.scope.leave();
1831                 }
1832                 addVars(c.stats, switchEnv.info.scope);
1833 
1834                 preFlow(c);
1835                 c.completesNormally = flow.aliveAfter(caseEnv, c, make);
1836             }
1837             if (patternSwitch) {
1838                 chk.checkSwitchCaseStructure(cases);
1839                 chk.checkSwitchCaseLabelDominated(cases);
1840             }
1841             if (switchTree.hasTag(SWITCH)) {
1842                 ((JCSwitch) switchTree).hasUnconditionalPattern =
1843                         hasDefault || hasUnconditionalPattern || lastPatternErroneous;
1844                 ((JCSwitch) switchTree).patternSwitch = patternSwitch;
1845             } else if (switchTree.hasTag(SWITCH_EXPRESSION)) {
1846                 ((JCSwitchExpression) switchTree).hasUnconditionalPattern =
1847                         hasDefault || hasUnconditionalPattern || lastPatternErroneous;
1848                 ((JCSwitchExpression) switchTree).patternSwitch = patternSwitch;
1849             } else {
1850                 Assert.error(switchTree.getTag().name());
1851             }
1852         } finally {
1853             switchEnv.info.scope.leave();
1854         }
1855     }
1856     // where
1857         /** Add any variables defined in stats to the switch scope. */
1858         private static void addVars(List<JCStatement> stats, WriteableScope switchScope) {
1859             for (;stats.nonEmpty(); stats = stats.tail) {
1860                 JCTree stat = stats.head;
1861                 if (stat.hasTag(VARDEF))
1862                     switchScope.enter(((JCVariableDecl) stat).sym);
1863             }
1864         }
1865     // where
1866     /** Return the selected enumeration constant symbol, or null. */
1867     private Symbol enumConstant(JCTree tree, Type enumType) {
1868         if (tree.hasTag(IDENT)) {
1869             JCIdent ident = (JCIdent)tree;
1870             Name name = ident.name;
1871             for (Symbol sym : enumType.tsym.members().getSymbolsByName(name)) {
1872                 if (sym.kind == VAR) {
1873                     Symbol s = ident.sym = sym;
1874                     ((VarSymbol)s).getConstValue(); // ensure initializer is evaluated
1875                     ident.type = s.type;
1876                     return ((s.flags_field & Flags.ENUM) == 0)
1877                         ? null : s;
1878                 }
1879             }
1880         }
1881         return null;
1882     }
1883 
1884     public void visitSynchronized(JCSynchronized tree) {
1885         chk.checkRefType(tree.pos(), attribExpr(tree.lock, env));
1886         if (env.info.lint.isEnabled(LintCategory.SYNCHRONIZATION) && isValueBased(tree.lock.type)) {
1887             log.warning(LintCategory.SYNCHRONIZATION, tree.pos(), Warnings.AttemptToSynchronizeOnInstanceOfValueBasedClass);
1888         }
1889         attribStat(tree.body, env);
1890         result = null;
1891     }
1892         // where
1893         private boolean isValueBased(Type t) {
1894             return t != null && t.tsym != null && (t.tsym.flags() & VALUE_BASED) != 0;
1895         }
1896 
1897 
1898     public void visitTry(JCTry tree) {
1899         // Create a new local environment with a local
1900         Env<AttrContext> localEnv = env.dup(tree, env.info.dup(env.info.scope.dup()));
1901         try {
1902             boolean isTryWithResource = tree.resources.nonEmpty();
1903             // Create a nested environment for attributing the try block if needed
1904             Env<AttrContext> tryEnv = isTryWithResource ?
1905                 env.dup(tree, localEnv.info.dup(localEnv.info.scope.dup())) :
1906                 localEnv;
1907             try {
1908                 // Attribute resource declarations
1909                 for (JCTree resource : tree.resources) {
1910                     CheckContext twrContext = new Check.NestedCheckContext(resultInfo.checkContext) {
1911                         @Override
1912                         public void report(DiagnosticPosition pos, JCDiagnostic details) {
1913                             chk.basicHandler.report(pos, diags.fragment(Fragments.TryNotApplicableToType(details)));
1914                         }
1915                     };
1916                     ResultInfo twrResult =
1917                         new ResultInfo(KindSelector.VAR,
1918                                        syms.autoCloseableType,
1919                                        twrContext);
1920                     if (resource.hasTag(VARDEF)) {
1921                         attribStat(resource, tryEnv);
1922                         twrResult.check(resource, resource.type);
1923 
1924                         //check that resource type cannot throw InterruptedException
1925                         checkAutoCloseable(resource.pos(), localEnv, resource.type);
1926 
1927                         VarSymbol var = ((JCVariableDecl) resource).sym;
1928 
1929                         var.flags_field |= Flags.FINAL;
1930                         var.setData(ElementKind.RESOURCE_VARIABLE);
1931                     } else {
1932                         attribTree(resource, tryEnv, twrResult);
1933                     }
1934                 }
1935                 // Attribute body
1936                 attribStat(tree.body, tryEnv);
1937             } finally {
1938                 if (isTryWithResource)
1939                     tryEnv.info.scope.leave();
1940             }
1941 
1942             // Attribute catch clauses
1943             for (List<JCCatch> l = tree.catchers; l.nonEmpty(); l = l.tail) {
1944                 JCCatch c = l.head;
1945                 Env<AttrContext> catchEnv =
1946                     localEnv.dup(c, localEnv.info.dup(localEnv.info.scope.dup()));
1947                 try {
1948                     Type ctype = attribStat(c.param, catchEnv);
1949                     if (TreeInfo.isMultiCatch(c)) {
1950                         //multi-catch parameter is implicitly marked as final
1951                         c.param.sym.flags_field |= FINAL | UNION;
1952                     }
1953                     if (c.param.sym.kind == VAR) {
1954                         c.param.sym.setData(ElementKind.EXCEPTION_PARAMETER);
1955                     }
1956                     chk.checkType(c.param.vartype.pos(),
1957                                   chk.checkClassType(c.param.vartype.pos(), ctype),
1958                                   syms.throwableType);
1959                     attribStat(c.body, catchEnv);
1960                 } finally {
1961                     catchEnv.info.scope.leave();
1962                 }
1963             }
1964 
1965             // Attribute finalizer
1966             if (tree.finalizer != null) attribStat(tree.finalizer, localEnv);
1967             result = null;
1968         }
1969         finally {
1970             localEnv.info.scope.leave();
1971         }
1972     }
1973 
1974     void checkAutoCloseable(DiagnosticPosition pos, Env<AttrContext> env, Type resource) {
1975         if (!resource.isErroneous() &&
1976             types.asSuper(resource, syms.autoCloseableType.tsym) != null &&
1977             !types.isSameType(resource, syms.autoCloseableType)) { // Don't emit warning for AutoCloseable itself
1978             Symbol close = syms.noSymbol;
1979             Log.DiagnosticHandler discardHandler = new Log.DiscardDiagnosticHandler(log);
1980             try {
1981                 close = rs.resolveQualifiedMethod(pos,
1982                         env,
1983                         types.skipTypeVars(resource, false),
1984                         names.close,
1985                         List.nil(),
1986                         List.nil());
1987             }
1988             finally {
1989                 log.popDiagnosticHandler(discardHandler);
1990             }
1991             if (close.kind == MTH &&
1992                     close.overrides(syms.autoCloseableClose, resource.tsym, types, true) &&
1993                     chk.isHandled(syms.interruptedExceptionType, types.memberType(resource, close).getThrownTypes()) &&
1994                     env.info.lint.isEnabled(LintCategory.TRY)) {
1995                 log.warning(LintCategory.TRY, pos, Warnings.TryResourceThrowsInterruptedExc(resource));
1996             }
1997         }
1998     }
1999 
2000     public void visitConditional(JCConditional tree) {
2001         Type condtype = attribExpr(tree.cond, env, syms.booleanType);
2002         MatchBindings condBindings = matchBindings;
2003 
2004         tree.polyKind = (pt().hasTag(NONE) && pt() != Type.recoveryType && pt() != Infer.anyPoly ||
2005                 isBooleanOrNumeric(env, tree)) ?
2006                 PolyKind.STANDALONE : PolyKind.POLY;
2007 
2008         if (tree.polyKind == PolyKind.POLY && resultInfo.pt.hasTag(VOID)) {
2009             //this means we are returning a poly conditional from void-compatible lambda expression
2010             resultInfo.checkContext.report(tree, diags.fragment(Fragments.ConditionalTargetCantBeVoid));
2011             result = tree.type = types.createErrorType(resultInfo.pt);
2012             return;
2013         }
2014 
2015         ResultInfo condInfo = tree.polyKind == PolyKind.STANDALONE ?
2016                 unknownExprInfo :
2017                 resultInfo.dup(conditionalContext(resultInfo.checkContext));
2018 
2019 
2020         // x ? y : z
2021         // include x's bindings when true in y
2022         // include x's bindings when false in z
2023 
2024         Type truetype;
2025         Env<AttrContext> trueEnv = bindingEnv(env, condBindings.bindingsWhenTrue);
2026         try {
2027             truetype = attribTree(tree.truepart, trueEnv, condInfo);
2028         } finally {
2029             trueEnv.info.scope.leave();
2030         }
2031 
2032         MatchBindings trueBindings = matchBindings;
2033 
2034         Type falsetype;
2035         Env<AttrContext> falseEnv = bindingEnv(env, condBindings.bindingsWhenFalse);
2036         try {
2037             falsetype = attribTree(tree.falsepart, falseEnv, condInfo);
2038         } finally {
2039             falseEnv.info.scope.leave();
2040         }
2041 
2042         MatchBindings falseBindings = matchBindings;
2043 
2044         Type owntype = (tree.polyKind == PolyKind.STANDALONE) ?
2045                 condType(List.of(tree.truepart.pos(), tree.falsepart.pos()),
2046                          List.of(truetype, falsetype)) : pt();
2047         if (condtype.constValue() != null &&
2048                 truetype.constValue() != null &&
2049                 falsetype.constValue() != null &&
2050                 !owntype.hasTag(NONE)) {
2051             //constant folding
2052             owntype = cfolder.coerce(condtype.isTrue() ? truetype : falsetype, owntype);
2053         }
2054         result = check(tree, owntype, KindSelector.VAL, resultInfo);
2055         matchBindings = matchBindingsComputer.conditional(tree, condBindings, trueBindings, falseBindings);
2056     }
2057     //where
2058         private boolean isBooleanOrNumeric(Env<AttrContext> env, JCExpression tree) {
2059             switch (tree.getTag()) {
2060                 case LITERAL: return ((JCLiteral)tree).typetag.isSubRangeOf(DOUBLE) ||
2061                               ((JCLiteral)tree).typetag == BOOLEAN ||
2062                               ((JCLiteral)tree).typetag == BOT;
2063                 case LAMBDA: case REFERENCE: return false;
2064                 case PARENS: return isBooleanOrNumeric(env, ((JCParens)tree).expr);
2065                 case CONDEXPR:
2066                     JCConditional condTree = (JCConditional)tree;
2067                     return isBooleanOrNumeric(env, condTree.truepart) &&
2068                             isBooleanOrNumeric(env, condTree.falsepart);
2069                 case APPLY:
2070                     JCMethodInvocation speculativeMethodTree =
2071                             (JCMethodInvocation)deferredAttr.attribSpeculative(
2072                                     tree, env, unknownExprInfo,
2073                                     argumentAttr.withLocalCacheContext());
2074                     Symbol msym = TreeInfo.symbol(speculativeMethodTree.meth);
2075                     Type receiverType = speculativeMethodTree.meth.hasTag(IDENT) ?
2076                             env.enclClass.type :
2077                             ((JCFieldAccess)speculativeMethodTree.meth).selected.type;
2078                     Type owntype = types.memberType(receiverType, msym).getReturnType();
2079                     return primitiveOrBoxed(owntype);
2080                 case NEWCLASS:
2081                     JCExpression className =
2082                             removeClassParams.translate(((JCNewClass)tree).clazz);
2083                     JCExpression speculativeNewClassTree =
2084                             (JCExpression)deferredAttr.attribSpeculative(
2085                                     className, env, unknownTypeInfo,
2086                                     argumentAttr.withLocalCacheContext());
2087                     return primitiveOrBoxed(speculativeNewClassTree.type);
2088                 default:
2089                     Type speculativeType = deferredAttr.attribSpeculative(tree, env, unknownExprInfo,
2090                             argumentAttr.withLocalCacheContext()).type;
2091                     return primitiveOrBoxed(speculativeType);
2092             }
2093         }
2094         //where
2095             boolean primitiveOrBoxed(Type t) {
2096                 return (!t.hasTag(TYPEVAR) && !t.isErroneous() && types.unboxedTypeOrType(t).isPrimitive());
2097             }
2098 
2099             TreeTranslator removeClassParams = new TreeTranslator() {
2100                 @Override
2101                 public void visitTypeApply(JCTypeApply tree) {
2102                     result = translate(tree.clazz);
2103                 }
2104             };
2105 
2106         CheckContext conditionalContext(CheckContext checkContext) {
2107             return new Check.NestedCheckContext(checkContext) {
2108                 //this will use enclosing check context to check compatibility of
2109                 //subexpression against target type; if we are in a method check context,
2110                 //depending on whether boxing is allowed, we could have incompatibilities
2111                 @Override
2112                 public void report(DiagnosticPosition pos, JCDiagnostic details) {
2113                     enclosingContext.report(pos, diags.fragment(Fragments.IncompatibleTypeInConditional(details)));
2114                 }
2115             };
2116         }
2117 
2118         /** Compute the type of a conditional expression, after
2119          *  checking that it exists.  See JLS 15.25. Does not take into
2120          *  account the special case where condition and both arms
2121          *  are constants.
2122          *
2123          *  @param pos      The source position to be used for error
2124          *                  diagnostics.
2125          *  @param thentype The type of the expression's then-part.
2126          *  @param elsetype The type of the expression's else-part.
2127          */
2128         Type condType(List<DiagnosticPosition> positions, List<Type> condTypes) {
2129             if (condTypes.isEmpty()) {
2130                 return syms.objectType; //TODO: how to handle?
2131             }
2132             Type first = condTypes.head;
2133             // If same type, that is the result
2134             if (condTypes.tail.stream().allMatch(t -> types.isSameType(first, t)))
2135                 return first.baseType();
2136 
2137             List<Type> unboxedTypes = condTypes.stream()
2138                                                .map(t -> t.isPrimitive() ? t : types.unboxedType(t))
2139                                                .collect(List.collector());
2140 
2141             // Otherwise, if both arms can be converted to a numeric
2142             // type, return the least numeric type that fits both arms
2143             // (i.e. return larger of the two, or return int if one
2144             // arm is short, the other is char).
2145             if (unboxedTypes.stream().allMatch(t -> t.isPrimitive())) {
2146                 // If one arm has an integer subrange type (i.e., byte,
2147                 // short, or char), and the other is an integer constant
2148                 // that fits into the subrange, return the subrange type.
2149                 for (Type type : unboxedTypes) {
2150                     if (!type.getTag().isStrictSubRangeOf(INT)) {
2151                         continue;
2152                     }
2153                     if (unboxedTypes.stream().filter(t -> t != type).allMatch(t -> t.hasTag(INT) && types.isAssignable(t, type)))
2154                         return type.baseType();
2155                 }
2156 
2157                 for (TypeTag tag : primitiveTags) {
2158                     Type candidate = syms.typeOfTag[tag.ordinal()];
2159                     if (unboxedTypes.stream().allMatch(t -> types.isSubtype(t, candidate))) {
2160                         return candidate;
2161                     }
2162                 }
2163             }
2164 
2165             // Those were all the cases that could result in a primitive
2166             condTypes = condTypes.stream()
2167                                  .map(t -> t.isPrimitive() ? types.boxedClass(t).type : t)
2168                                  .collect(List.collector());
2169 
2170             for (Type type : condTypes) {
2171                 if (condTypes.stream().filter(t -> t != type).allMatch(t -> types.isAssignable(t, type)))
2172                     return type.baseType();
2173             }
2174 
2175             Iterator<DiagnosticPosition> posIt = positions.iterator();
2176 
2177             condTypes = condTypes.stream()
2178                                  .map(t -> chk.checkNonVoid(posIt.next(), t))
2179                                  .collect(List.collector());
2180 
2181             // both are known to be reference types.  The result is
2182             // lub(thentype,elsetype). This cannot fail, as it will
2183             // always be possible to infer "Object" if nothing better.
2184             return types.lub(condTypes.stream()
2185                         .map(t -> t.baseType())
2186                         .filter(t -> !t.hasTag(BOT))
2187                         .collect(List.collector()));
2188         }
2189 
2190     static final TypeTag[] primitiveTags = new TypeTag[]{
2191         BYTE,
2192         CHAR,
2193         SHORT,
2194         INT,
2195         LONG,
2196         FLOAT,
2197         DOUBLE,
2198         BOOLEAN,
2199     };
2200 
2201     Env<AttrContext> bindingEnv(Env<AttrContext> env, List<BindingSymbol> bindings) {
2202         return bindingEnv(env, env.tree, bindings);
2203     }
2204 
2205     Env<AttrContext> bindingEnv(Env<AttrContext> env, JCTree newTree, List<BindingSymbol> bindings) {
2206         Env<AttrContext> env1 = env.dup(newTree, env.info.dup(env.info.scope.dup()));
2207         bindings.forEach(env1.info.scope::enter);
2208         return env1;
2209     }
2210 
2211     public void visitIf(JCIf tree) {
2212         attribExpr(tree.cond, env, syms.booleanType);
2213 
2214         // if (x) { y } [ else z ]
2215         // include x's bindings when true in y
2216         // include x's bindings when false in z
2217 
2218         MatchBindings condBindings = matchBindings;
2219         Env<AttrContext> thenEnv = bindingEnv(env, condBindings.bindingsWhenTrue);
2220 
2221         try {
2222             attribStat(tree.thenpart, thenEnv);
2223         } finally {
2224             thenEnv.info.scope.leave();
2225         }
2226 
2227         preFlow(tree.thenpart);
2228         boolean aliveAfterThen = flow.aliveAfter(env, tree.thenpart, make);
2229         boolean aliveAfterElse;
2230 
2231         if (tree.elsepart != null) {
2232             Env<AttrContext> elseEnv = bindingEnv(env, condBindings.bindingsWhenFalse);
2233             try {
2234                 attribStat(tree.elsepart, elseEnv);
2235             } finally {
2236                 elseEnv.info.scope.leave();
2237             }
2238             preFlow(tree.elsepart);
2239             aliveAfterElse = flow.aliveAfter(env, tree.elsepart, make);
2240         } else {
2241             aliveAfterElse = true;
2242         }
2243 
2244         chk.checkEmptyIf(tree);
2245 
2246         List<BindingSymbol> afterIfBindings = List.nil();
2247 
2248         if (aliveAfterThen && !aliveAfterElse) {
2249             afterIfBindings = condBindings.bindingsWhenTrue;
2250         } else if (aliveAfterElse && !aliveAfterThen) {
2251             afterIfBindings = condBindings.bindingsWhenFalse;
2252         }
2253 
2254         afterIfBindings.forEach(env.info.scope::enter);
2255         afterIfBindings.forEach(BindingSymbol::preserveBinding);
2256 
2257         result = null;
2258     }
2259 
2260         void preFlow(JCTree tree) {
2261             attrRecover.doRecovery();
2262             new PostAttrAnalyzer() {
2263                 @Override
2264                 public void scan(JCTree tree) {
2265                     if (tree == null ||
2266                             (tree.type != null &&
2267                             tree.type == Type.stuckType)) {
2268                         //don't touch stuck expressions!
2269                         return;
2270                     }
2271                     super.scan(tree);
2272                 }
2273 
2274                 @Override
2275                 public void visitClassDef(JCClassDecl that) {
2276                     if (that.sym != null) {
2277                         // Method preFlow shouldn't visit class definitions
2278                         // that have not been entered and attributed.
2279                         // See JDK-8254557 and JDK-8203277 for more details.
2280                         super.visitClassDef(that);
2281                     }
2282                 }
2283 
2284                 @Override
2285                 public void visitLambda(JCLambda that) {
2286                     if (that.type != null) {
2287                         // Method preFlow shouldn't visit lambda expressions
2288                         // that have not been entered and attributed.
2289                         // See JDK-8254557 and JDK-8203277 for more details.
2290                         super.visitLambda(that);
2291                     }
2292                 }
2293             }.scan(tree);
2294         }
2295 
2296     public void visitExec(JCExpressionStatement tree) {
2297         //a fresh environment is required for 292 inference to work properly ---
2298         //see Infer.instantiatePolymorphicSignatureInstance()
2299         Env<AttrContext> localEnv = env.dup(tree);
2300         attribExpr(tree.expr, localEnv);
2301         result = null;
2302     }
2303 
2304     public void visitBreak(JCBreak tree) {
2305         tree.target = findJumpTarget(tree.pos(), tree.getTag(), tree.label, env);
2306         result = null;
2307     }
2308 
2309     public void visitYield(JCYield tree) {
2310         if (env.info.yieldResult != null) {
2311             attribTree(tree.value, env, env.info.yieldResult);
2312             tree.target = findJumpTarget(tree.pos(), tree.getTag(), names.empty, env);
2313         } else {
2314             log.error(tree.pos(), tree.value.hasTag(PARENS)
2315                     ? Errors.NoSwitchExpressionQualify
2316                     : Errors.NoSwitchExpression);
2317             attribTree(tree.value, env, unknownExprInfo);
2318         }
2319         result = null;
2320     }
2321 
2322     public void visitContinue(JCContinue tree) {
2323         tree.target = findJumpTarget(tree.pos(), tree.getTag(), tree.label, env);
2324         result = null;
2325     }
2326     //where
2327         /** Return the target of a break, continue or yield statement,
2328          *  if it exists, report an error if not.
2329          *  Note: The target of a labelled break or continue is the
2330          *  (non-labelled) statement tree referred to by the label,
2331          *  not the tree representing the labelled statement itself.
2332          *
2333          *  @param pos     The position to be used for error diagnostics
2334          *  @param tag     The tag of the jump statement. This is either
2335          *                 Tree.BREAK or Tree.CONTINUE.
2336          *  @param label   The label of the jump statement, or null if no
2337          *                 label is given.
2338          *  @param env     The environment current at the jump statement.
2339          */
2340         private JCTree findJumpTarget(DiagnosticPosition pos,
2341                                                    JCTree.Tag tag,
2342                                                    Name label,
2343                                                    Env<AttrContext> env) {
2344             Pair<JCTree, Error> jumpTarget = findJumpTargetNoError(tag, label, env);
2345 
2346             if (jumpTarget.snd != null) {
2347                 log.error(pos, jumpTarget.snd);
2348             }
2349 
2350             return jumpTarget.fst;
2351         }
2352         /** Return the target of a break or continue statement, if it exists,
2353          *  report an error if not.
2354          *  Note: The target of a labelled break or continue is the
2355          *  (non-labelled) statement tree referred to by the label,
2356          *  not the tree representing the labelled statement itself.
2357          *
2358          *  @param tag     The tag of the jump statement. This is either
2359          *                 Tree.BREAK or Tree.CONTINUE.
2360          *  @param label   The label of the jump statement, or null if no
2361          *                 label is given.
2362          *  @param env     The environment current at the jump statement.
2363          */
2364         private Pair<JCTree, JCDiagnostic.Error> findJumpTargetNoError(JCTree.Tag tag,
2365                                                                        Name label,
2366                                                                        Env<AttrContext> env) {
2367             // Search environments outwards from the point of jump.
2368             Env<AttrContext> env1 = env;
2369             JCDiagnostic.Error pendingError = null;
2370             LOOP:
2371             while (env1 != null) {
2372                 switch (env1.tree.getTag()) {
2373                     case LABELLED:
2374                         JCLabeledStatement labelled = (JCLabeledStatement)env1.tree;
2375                         if (label == labelled.label) {
2376                             // If jump is a continue, check that target is a loop.
2377                             if (tag == CONTINUE) {
2378                                 if (!labelled.body.hasTag(DOLOOP) &&
2379                                         !labelled.body.hasTag(WHILELOOP) &&
2380                                         !labelled.body.hasTag(FORLOOP) &&
2381                                         !labelled.body.hasTag(FOREACHLOOP)) {
2382                                     pendingError = Errors.NotLoopLabel(label);
2383                                 }
2384                                 // Found labelled statement target, now go inwards
2385                                 // to next non-labelled tree.
2386                                 return Pair.of(TreeInfo.referencedStatement(labelled), pendingError);
2387                             } else {
2388                                 return Pair.of(labelled, pendingError);
2389                             }
2390                         }
2391                         break;
2392                     case DOLOOP:
2393                     case WHILELOOP:
2394                     case FORLOOP:
2395                     case FOREACHLOOP:
2396                         if (label == null) return Pair.of(env1.tree, pendingError);
2397                         break;
2398                     case SWITCH:
2399                         if (label == null && tag == BREAK) return Pair.of(env1.tree, null);
2400                         break;
2401                     case SWITCH_EXPRESSION:
2402                         if (tag == YIELD) {
2403                             return Pair.of(env1.tree, null);
2404                         } else if (tag == BREAK) {
2405                             pendingError = Errors.BreakOutsideSwitchExpression;
2406                         } else {
2407                             pendingError = Errors.ContinueOutsideSwitchExpression;
2408                         }
2409                         break;
2410                     case LAMBDA:
2411                     case METHODDEF:
2412                     case CLASSDEF:
2413                         break LOOP;
2414                     default:
2415                 }
2416                 env1 = env1.next;
2417             }
2418             if (label != null)
2419                 return Pair.of(null, Errors.UndefLabel(label));
2420             else if (pendingError != null)
2421                 return Pair.of(null, pendingError);
2422             else if (tag == CONTINUE)
2423                 return Pair.of(null, Errors.ContOutsideLoop);
2424             else
2425                 return Pair.of(null, Errors.BreakOutsideSwitchLoop);
2426         }
2427 
2428     public void visitReturn(JCReturn tree) {
2429         // Check that there is an enclosing method which is
2430         // nested within than the enclosing class.
2431         if (env.info.returnResult == null) {
2432             log.error(tree.pos(), Errors.RetOutsideMeth);
2433         } else if (env.info.yieldResult != null) {
2434             log.error(tree.pos(), Errors.ReturnOutsideSwitchExpression);
2435         } else if (!env.info.isLambda &&
2436                 !env.info.isNewClass &&
2437                 env.enclMethod != null &&
2438                 TreeInfo.isCompactConstructor(env.enclMethod)) {
2439             log.error(env.enclMethod,
2440                     Errors.InvalidCanonicalConstructorInRecord(Fragments.Compact, env.enclMethod.sym.name, Fragments.CanonicalCantHaveReturnStatement));
2441         } else {
2442             // Attribute return expression, if it exists, and check that
2443             // it conforms to result type of enclosing method.
2444             if (tree.expr != null) {
2445                 if (env.info.returnResult.pt.hasTag(VOID)) {
2446                     env.info.returnResult.checkContext.report(tree.expr.pos(),
2447                               diags.fragment(Fragments.UnexpectedRetVal));
2448                 }
2449                 attribTree(tree.expr, env, env.info.returnResult);
2450             } else if (!env.info.returnResult.pt.hasTag(VOID) &&
2451                     !env.info.returnResult.pt.hasTag(NONE)) {
2452                 env.info.returnResult.checkContext.report(tree.pos(),
2453                               diags.fragment(Fragments.MissingRetVal(env.info.returnResult.pt)));
2454             }
2455         }
2456         result = null;
2457     }
2458 
2459     public void visitThrow(JCThrow tree) {
2460         Type owntype = attribExpr(tree.expr, env, Type.noType);
2461         chk.checkType(tree, owntype, syms.throwableType);
2462         result = null;
2463     }
2464 
2465     public void visitAssert(JCAssert tree) {
2466         attribExpr(tree.cond, env, syms.booleanType);
2467         if (tree.detail != null) {
2468             chk.checkNonVoid(tree.detail.pos(), attribExpr(tree.detail, env));
2469         }
2470         result = null;
2471     }
2472 
2473      /** Visitor method for method invocations.
2474      *  NOTE: The method part of an application will have in its type field
2475      *        the return type of the method, not the method's type itself!
2476      */
2477     public void visitApply(JCMethodInvocation tree) {
2478         // The local environment of a method application is
2479         // a new environment nested in the current one.
2480         Env<AttrContext> localEnv = env.dup(tree, env.info.dup());
2481 
2482         // The types of the actual method arguments.
2483         List<Type> argtypes;
2484 
2485         // The types of the actual method type arguments.
2486         List<Type> typeargtypes = null;
2487 
2488         Name methName = TreeInfo.name(tree.meth);
2489 
2490         boolean isConstructorCall =
2491             methName == names._this || methName == names._super;
2492 
2493         ListBuffer<Type> argtypesBuf = new ListBuffer<>();
2494         if (isConstructorCall) {
2495             // We are seeing a ...this(...) or ...super(...) call.
2496             // Check that this is the first statement in a constructor.
2497             checkFirstConstructorStat(tree, env.enclMethod, true);
2498 
2499             // Record the fact
2500             // that this is a constructor call (using isSelfCall).
2501             localEnv.info.isSelfCall = true;
2502 
2503             // Attribute arguments, yielding list of argument types.
2504             localEnv.info.constructorArgs = true;
2505             KindSelector kind = attribArgs(KindSelector.MTH, tree.args, localEnv, argtypesBuf);
2506             localEnv.info.constructorArgs = false;
2507             argtypes = argtypesBuf.toList();
2508             typeargtypes = attribTypes(tree.typeargs, localEnv);
2509 
2510             // Variable `site' points to the class in which the called
2511             // constructor is defined.
2512             Type site = env.enclClass.sym.type;
2513             if (methName == names._super) {
2514                 if (site == syms.objectType) {
2515                     log.error(tree.meth.pos(), Errors.NoSuperclass(site));
2516                     site = types.createErrorType(syms.objectType);
2517                 } else {
2518                     site = types.supertype(site);
2519                 }
2520             }
2521 
2522             if (site.hasTag(CLASS)) {
2523                 Type encl = site.getEnclosingType();
2524                 while (encl != null && encl.hasTag(TYPEVAR))
2525                     encl = encl.getUpperBound();
2526                 if (encl.hasTag(CLASS)) {
2527                     // we are calling a nested class
2528 
2529                     if (tree.meth.hasTag(SELECT)) {
2530                         JCTree qualifier = ((JCFieldAccess) tree.meth).selected;
2531 
2532                         // We are seeing a prefixed call, of the form
2533                         //     <expr>.super(...).
2534                         // Check that the prefix expression conforms
2535                         // to the outer instance type of the class.
2536                         chk.checkRefType(qualifier.pos(),
2537                                          attribExpr(qualifier, localEnv,
2538                                                     encl));
2539                     } else if (methName == names._super) {
2540                         // qualifier omitted; check for existence
2541                         // of an appropriate implicit qualifier.
2542                         rs.resolveImplicitThis(tree.meth.pos(),
2543                                                localEnv, site, true);
2544                     }
2545                 } else if (tree.meth.hasTag(SELECT)) {
2546                     log.error(tree.meth.pos(),
2547                               Errors.IllegalQualNotIcls(site.tsym));
2548                     attribExpr(((JCFieldAccess) tree.meth).selected, localEnv, site);
2549                 }
2550 
2551                 // if we're calling a java.lang.Enum constructor,
2552                 // prefix the implicit String and int parameters
2553                 if (site.tsym == syms.enumSym)
2554                     argtypes = argtypes.prepend(syms.intType).prepend(syms.stringType);
2555 
2556                 // Resolve the called constructor under the assumption
2557                 // that we are referring to a superclass instance of the
2558                 // current instance (JLS ???).
2559                 boolean selectSuperPrev = localEnv.info.selectSuper;
2560                 localEnv.info.selectSuper = true;
2561                 localEnv.info.pendingResolutionPhase = null;
2562                 Symbol sym = rs.resolveConstructor(
2563                     tree.meth.pos(), localEnv, site, argtypes, typeargtypes);
2564                 localEnv.info.selectSuper = selectSuperPrev;
2565 
2566                 // Set method symbol to resolved constructor...
2567                 TreeInfo.setSymbol(tree.meth, sym);
2568 
2569                 // ...and check that it is legal in the current context.
2570                 // (this will also set the tree's type)
2571                 Type mpt = newMethodTemplate(resultInfo.pt, argtypes, typeargtypes);
2572                 checkId(tree.meth, site, sym, localEnv,
2573                         new ResultInfo(kind, mpt));
2574             } else if (site.hasTag(ERROR) && tree.meth.hasTag(SELECT)) {
2575                 attribExpr(((JCFieldAccess) tree.meth).selected, localEnv, site);
2576             }
2577             // Otherwise, `site' is an error type and we do nothing
2578             result = tree.type = syms.voidType;
2579         } else {
2580             // Otherwise, we are seeing a regular method call.
2581             // Attribute the arguments, yielding list of argument types, ...
2582             KindSelector kind = attribArgs(KindSelector.VAL, tree.args, localEnv, argtypesBuf);
2583             argtypes = argtypesBuf.toList();
2584             typeargtypes = attribAnyTypes(tree.typeargs, localEnv);
2585 
2586             // ... and attribute the method using as a prototype a methodtype
2587             // whose formal argument types is exactly the list of actual
2588             // arguments (this will also set the method symbol).
2589             Type mpt = newMethodTemplate(resultInfo.pt, argtypes, typeargtypes);
2590             localEnv.info.pendingResolutionPhase = null;
2591             Type mtype = attribTree(tree.meth, localEnv, new ResultInfo(kind, mpt, resultInfo.checkContext));
2592 
2593             // Compute the result type.
2594             Type restype = mtype.getReturnType();
2595             if (restype.hasTag(WILDCARD))
2596                 throw new AssertionError(mtype);
2597 
2598             Type qualifier = (tree.meth.hasTag(SELECT))
2599                     ? ((JCFieldAccess) tree.meth).selected.type
2600                     : env.enclClass.sym.type;
2601             Symbol msym = TreeInfo.symbol(tree.meth);
2602             restype = adjustMethodReturnType(msym, qualifier, methName, argtypes, restype);
2603 
2604             chk.checkRefTypes(tree.typeargs, typeargtypes);
2605 
2606             // Check that value of resulting type is admissible in the
2607             // current context.  Also, capture the return type
2608             Type capturedRes = resultInfo.checkContext.inferenceContext().cachedCapture(tree, restype, true);
2609             result = check(tree, capturedRes, KindSelector.VAL, resultInfo);
2610         }
2611         chk.validate(tree.typeargs, localEnv);
2612     }
2613     //where
2614         Type adjustMethodReturnType(Symbol msym, Type qualifierType, Name methodName, List<Type> argtypes, Type restype) {
2615             if (msym != null &&
2616                     (msym.owner == syms.objectType.tsym || msym.owner.isInterface()) &&
2617                     methodName == names.getClass &&
2618                     argtypes.isEmpty()) {
2619                 // as a special case, x.getClass() has type Class<? extends |X|>
2620                 return new ClassType(restype.getEnclosingType(),
2621                         List.of(new WildcardType(types.erasure(qualifierType.baseType()),
2622                                 BoundKind.EXTENDS,
2623                                 syms.boundClass)),
2624                         restype.tsym,
2625                         restype.getMetadata());
2626             } else if (msym != null &&
2627                     msym.owner == syms.arrayClass &&
2628                     methodName == names.clone &&
2629                     types.isArray(qualifierType)) {
2630                 // as a special case, array.clone() has a result that is
2631                 // the same as static type of the array being cloned
2632                 return qualifierType;
2633             } else {
2634                 return restype;
2635             }
2636         }
2637 
2638         /** Check that given application node appears as first statement
2639          *  in a constructor call.
2640          *  @param tree          The application node
2641          *  @param enclMethod    The enclosing method of the application.
2642          *  @param error         Should an error be issued?
2643          */
2644         boolean checkFirstConstructorStat(JCMethodInvocation tree, JCMethodDecl enclMethod, boolean error) {
2645             if (enclMethod != null && enclMethod.name == names.init) {
2646                 JCBlock body = enclMethod.body;
2647                 if (body.stats.head.hasTag(EXEC) &&
2648                     ((JCExpressionStatement) body.stats.head).expr == tree)
2649                     return true;
2650             }
2651             if (error) {
2652                 log.error(tree.pos(),
2653                         Errors.CallMustBeFirstStmtInCtor(TreeInfo.name(tree.meth)));
2654             }
2655             return false;
2656         }
2657 
2658         /** Obtain a method type with given argument types.
2659          */
2660         Type newMethodTemplate(Type restype, List<Type> argtypes, List<Type> typeargtypes) {
2661             MethodType mt = new MethodType(argtypes, restype, List.nil(), syms.methodClass);
2662             return (typeargtypes == null) ? mt : (Type)new ForAll(typeargtypes, mt);
2663         }
2664 
2665     public void visitNewClass(final JCNewClass tree) {
2666         Type owntype = types.createErrorType(tree.type);
2667 
2668         // The local environment of a class creation is
2669         // a new environment nested in the current one.
2670         Env<AttrContext> localEnv = env.dup(tree, env.info.dup());
2671 
2672         // The anonymous inner class definition of the new expression,
2673         // if one is defined by it.
2674         JCClassDecl cdef = tree.def;
2675 
2676         // If enclosing class is given, attribute it, and
2677         // complete class name to be fully qualified
2678         JCExpression clazz = tree.clazz; // Class field following new
2679         JCExpression clazzid;            // Identifier in class field
2680         JCAnnotatedType annoclazzid;     // Annotated type enclosing clazzid
2681         annoclazzid = null;
2682 
2683         if (clazz.hasTag(TYPEAPPLY)) {
2684             clazzid = ((JCTypeApply) clazz).clazz;
2685             if (clazzid.hasTag(ANNOTATED_TYPE)) {
2686                 annoclazzid = (JCAnnotatedType) clazzid;
2687                 clazzid = annoclazzid.underlyingType;
2688             }
2689         } else {
2690             if (clazz.hasTag(ANNOTATED_TYPE)) {
2691                 annoclazzid = (JCAnnotatedType) clazz;
2692                 clazzid = annoclazzid.underlyingType;
2693             } else {
2694                 clazzid = clazz;
2695             }
2696         }
2697 
2698         JCExpression clazzid1 = clazzid; // The same in fully qualified form
2699 
2700         if (tree.encl != null) {
2701             // We are seeing a qualified new, of the form
2702             //    <expr>.new C <...> (...) ...
2703             // In this case, we let clazz stand for the name of the
2704             // allocated class C prefixed with the type of the qualifier
2705             // expression, so that we can
2706             // resolve it with standard techniques later. I.e., if
2707             // <expr> has type T, then <expr>.new C <...> (...)
2708             // yields a clazz T.C.
2709             Type encltype = chk.checkRefType(tree.encl.pos(),
2710                                              attribExpr(tree.encl, env));
2711             // TODO 308: in <expr>.new C, do we also want to add the type annotations
2712             // from expr to the combined type, or not? Yes, do this.
2713             clazzid1 = make.at(clazz.pos).Select(make.Type(encltype),
2714                                                  ((JCIdent) clazzid).name);
2715 
2716             EndPosTable endPosTable = this.env.toplevel.endPositions;
2717             endPosTable.storeEnd(clazzid1, clazzid.getEndPosition(endPosTable));
2718             if (clazz.hasTag(ANNOTATED_TYPE)) {
2719                 JCAnnotatedType annoType = (JCAnnotatedType) clazz;
2720                 List<JCAnnotation> annos = annoType.annotations;
2721 
2722                 if (annoType.underlyingType.hasTag(TYPEAPPLY)) {
2723                     clazzid1 = make.at(tree.pos).
2724                         TypeApply(clazzid1,
2725                                   ((JCTypeApply) clazz).arguments);
2726                 }
2727 
2728                 clazzid1 = make.at(tree.pos).
2729                     AnnotatedType(annos, clazzid1);
2730             } else if (clazz.hasTag(TYPEAPPLY)) {
2731                 clazzid1 = make.at(tree.pos).
2732                     TypeApply(clazzid1,
2733                               ((JCTypeApply) clazz).arguments);
2734             }
2735 
2736             clazz = clazzid1;
2737         }
2738 
2739         // Attribute clazz expression and store
2740         // symbol + type back into the attributed tree.
2741         Type clazztype;
2742 
2743         try {
2744             env.info.isNewClass = true;
2745             clazztype = TreeInfo.isEnumInit(env.tree) ?
2746                 attribIdentAsEnumType(env, (JCIdent)clazz) :
2747                 attribType(clazz, env);
2748         } finally {
2749             env.info.isNewClass = false;
2750         }
2751 
2752         clazztype = chk.checkDiamond(tree, clazztype);
2753         chk.validate(clazz, localEnv);
2754         if (tree.encl != null) {
2755             // We have to work in this case to store
2756             // symbol + type back into the attributed tree.
2757             tree.clazz.type = clazztype;
2758             TreeInfo.setSymbol(clazzid, TreeInfo.symbol(clazzid1));
2759             clazzid.type = ((JCIdent) clazzid).sym.type;
2760             if (annoclazzid != null) {
2761                 annoclazzid.type = clazzid.type;
2762             }
2763             if (!clazztype.isErroneous()) {
2764                 if (cdef != null && clazztype.tsym.isInterface()) {
2765                     log.error(tree.encl.pos(), Errors.AnonClassImplIntfNoQualForNew);
2766                 } else if (clazztype.tsym.isStatic()) {
2767                     log.error(tree.encl.pos(), Errors.QualifiedNewOfStaticClass(clazztype.tsym));
2768                 }
2769             }
2770         } else if (!clazztype.tsym.isInterface() &&
2771                    clazztype.getEnclosingType().hasTag(CLASS)) {
2772             // Check for the existence of an apropos outer instance
2773             rs.resolveImplicitThis(tree.pos(), env, clazztype);
2774         }
2775 
2776         // Attribute constructor arguments.
2777         ListBuffer<Type> argtypesBuf = new ListBuffer<>();
2778         final KindSelector pkind =
2779             attribArgs(KindSelector.VAL, tree.args, localEnv, argtypesBuf);
2780         List<Type> argtypes = argtypesBuf.toList();
2781         List<Type> typeargtypes = attribTypes(tree.typeargs, localEnv);
2782 
2783         if (clazztype.hasTag(CLASS) || clazztype.hasTag(ERROR)) {
2784             // Enums may not be instantiated except implicitly
2785             if ((clazztype.tsym.flags_field & Flags.ENUM) != 0 &&
2786                 (!env.tree.hasTag(VARDEF) ||
2787                  (((JCVariableDecl) env.tree).mods.flags & Flags.ENUM) == 0 ||
2788                  ((JCVariableDecl) env.tree).init != tree))
2789                 log.error(tree.pos(), Errors.EnumCantBeInstantiated);
2790 
2791             boolean isSpeculativeDiamondInferenceRound = TreeInfo.isDiamond(tree) &&
2792                     resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.SPECULATIVE;
2793             boolean skipNonDiamondPath = false;
2794             // Check that class is not abstract
2795             if (cdef == null && !isSpeculativeDiamondInferenceRound && // class body may be nulled out in speculative tree copy
2796                 (clazztype.tsym.flags() & (ABSTRACT | INTERFACE)) != 0) {
2797                 log.error(tree.pos(),
2798                           Errors.AbstractCantBeInstantiated(clazztype.tsym));
2799                 skipNonDiamondPath = true;
2800             } else if (cdef != null && clazztype.tsym.isInterface()) {
2801                 // Check that no constructor arguments are given to
2802                 // anonymous classes implementing an interface
2803                 if (!argtypes.isEmpty())
2804                     log.error(tree.args.head.pos(), Errors.AnonClassImplIntfNoArgs);
2805 
2806                 if (!typeargtypes.isEmpty())
2807                     log.error(tree.typeargs.head.pos(), Errors.AnonClassImplIntfNoTypeargs);
2808 
2809                 // Error recovery: pretend no arguments were supplied.
2810                 argtypes = List.nil();
2811                 typeargtypes = List.nil();
2812                 skipNonDiamondPath = true;
2813             }
2814             if (TreeInfo.isDiamond(tree)) {
2815                 ClassType site = new ClassType(clazztype.getEnclosingType(),
2816                             clazztype.tsym.type.getTypeArguments(),
2817                                                clazztype.tsym,
2818                                                clazztype.getMetadata());
2819 
2820                 Env<AttrContext> diamondEnv = localEnv.dup(tree);
2821                 diamondEnv.info.selectSuper = cdef != null || tree.classDeclRemoved();
2822                 diamondEnv.info.pendingResolutionPhase = null;
2823 
2824                 //if the type of the instance creation expression is a class type
2825                 //apply method resolution inference (JLS 15.12.2.7). The return type
2826                 //of the resolved constructor will be a partially instantiated type
2827                 Symbol constructor = rs.resolveDiamond(tree.pos(),
2828                             diamondEnv,
2829                             site,
2830                             argtypes,
2831                             typeargtypes);
2832                 tree.constructor = constructor.baseSymbol();
2833 
2834                 final TypeSymbol csym = clazztype.tsym;
2835                 ResultInfo diamondResult = new ResultInfo(pkind, newMethodTemplate(resultInfo.pt, argtypes, typeargtypes),
2836                         diamondContext(tree, csym, resultInfo.checkContext), CheckMode.NO_TREE_UPDATE);
2837                 Type constructorType = tree.constructorType = types.createErrorType(clazztype);
2838                 constructorType = checkId(tree, site,
2839                         constructor,
2840                         diamondEnv,
2841                         diamondResult);
2842 
2843                 tree.clazz.type = types.createErrorType(clazztype);
2844                 if (!constructorType.isErroneous()) {
2845                     tree.clazz.type = clazz.type = constructorType.getReturnType();
2846                     tree.constructorType = types.createMethodTypeWithReturn(constructorType, syms.voidType);
2847                 }
2848                 clazztype = chk.checkClassType(tree.clazz, tree.clazz.type, true);
2849             }
2850 
2851             // Resolve the called constructor under the assumption
2852             // that we are referring to a superclass instance of the
2853             // current instance (JLS ???).
2854             else if (!skipNonDiamondPath) {
2855                 //the following code alters some of the fields in the current
2856                 //AttrContext - hence, the current context must be dup'ed in
2857                 //order to avoid downstream failures
2858                 Env<AttrContext> rsEnv = localEnv.dup(tree);
2859                 rsEnv.info.selectSuper = cdef != null;
2860                 rsEnv.info.pendingResolutionPhase = null;
2861                 tree.constructor = rs.resolveConstructor(
2862                     tree.pos(), rsEnv, clazztype, argtypes, typeargtypes);
2863                 if (cdef == null) { //do not check twice!
2864                     tree.constructorType = checkId(tree,
2865                             clazztype,
2866                             tree.constructor,
2867                             rsEnv,
2868                             new ResultInfo(pkind, newMethodTemplate(syms.voidType, argtypes, typeargtypes), CheckMode.NO_TREE_UPDATE));
2869                     if (rsEnv.info.lastResolveVarargs())
2870                         Assert.check(tree.constructorType.isErroneous() || tree.varargsElement != null);
2871                 }
2872             }
2873 
2874             if (cdef != null) {
2875                 visitAnonymousClassDefinition(tree, clazz, clazztype, cdef, localEnv, argtypes, typeargtypes, pkind);
2876                 return;
2877             }
2878 
2879             if (tree.constructor != null && tree.constructor.kind == MTH)
2880                 owntype = clazztype;
2881         }
2882         result = check(tree, owntype, KindSelector.VAL, resultInfo);
2883         InferenceContext inferenceContext = resultInfo.checkContext.inferenceContext();
2884         if (tree.constructorType != null && inferenceContext.free(tree.constructorType)) {
2885             //we need to wait for inference to finish and then replace inference vars in the constructor type
2886             inferenceContext.addFreeTypeListener(List.of(tree.constructorType),
2887                     instantiatedContext -> {
2888                         tree.constructorType = instantiatedContext.asInstType(tree.constructorType);
2889                     });
2890         }
2891         chk.validate(tree.typeargs, localEnv);
2892     }
2893 
2894         // where
2895         private void visitAnonymousClassDefinition(JCNewClass tree, JCExpression clazz, Type clazztype,
2896                                                    JCClassDecl cdef, Env<AttrContext> localEnv,
2897                                                    List<Type> argtypes, List<Type> typeargtypes,
2898                                                    KindSelector pkind) {
2899             // We are seeing an anonymous class instance creation.
2900             // In this case, the class instance creation
2901             // expression
2902             //
2903             //    E.new <typeargs1>C<typargs2>(args) { ... }
2904             //
2905             // is represented internally as
2906             //
2907             //    E . new <typeargs1>C<typargs2>(args) ( class <empty-name> { ... } )  .
2908             //
2909             // This expression is then *transformed* as follows:
2910             //
2911             // (1) add an extends or implements clause
2912             // (2) add a constructor.
2913             //
2914             // For instance, if C is a class, and ET is the type of E,
2915             // the expression
2916             //
2917             //    E.new <typeargs1>C<typargs2>(args) { ... }
2918             //
2919             // is translated to (where X is a fresh name and typarams is the
2920             // parameter list of the super constructor):
2921             //
2922             //   new <typeargs1>X(<*nullchk*>E, args) where
2923             //     X extends C<typargs2> {
2924             //       <typarams> X(ET e, args) {
2925             //         e.<typeargs1>super(args)
2926             //       }
2927             //       ...
2928             //     }
2929             InferenceContext inferenceContext = resultInfo.checkContext.inferenceContext();
2930             Type enclType = clazztype.getEnclosingType();
2931             if (enclType != null &&
2932                     enclType.hasTag(CLASS) &&
2933                     !chk.checkDenotable((ClassType)enclType)) {
2934                 log.error(tree.encl, Errors.EnclosingClassTypeNonDenotable(enclType));
2935             }
2936             final boolean isDiamond = TreeInfo.isDiamond(tree);
2937             if (isDiamond
2938                     && ((tree.constructorType != null && inferenceContext.free(tree.constructorType))
2939                     || (tree.clazz.type != null && inferenceContext.free(tree.clazz.type)))) {
2940                 final ResultInfo resultInfoForClassDefinition = this.resultInfo;
2941                 Env<AttrContext> dupLocalEnv = copyEnv(localEnv);
2942                 inferenceContext.addFreeTypeListener(List.of(tree.constructorType, tree.clazz.type),
2943                         instantiatedContext -> {
2944                             tree.constructorType = instantiatedContext.asInstType(tree.constructorType);
2945                             tree.clazz.type = clazz.type = instantiatedContext.asInstType(clazz.type);
2946                             ResultInfo prevResult = this.resultInfo;
2947                             try {
2948                                 this.resultInfo = resultInfoForClassDefinition;
2949                                 visitAnonymousClassDefinition(tree, clazz, clazz.type, cdef,
2950                                         dupLocalEnv, argtypes, typeargtypes, pkind);
2951                             } finally {
2952                                 this.resultInfo = prevResult;
2953                             }
2954                         });
2955             } else {
2956                 if (isDiamond && clazztype.hasTag(CLASS)) {
2957                     List<Type> invalidDiamondArgs = chk.checkDiamondDenotable((ClassType)clazztype);
2958                     if (!clazztype.isErroneous() && invalidDiamondArgs.nonEmpty()) {
2959                         // One or more types inferred in the previous steps is non-denotable.
2960                         Fragment fragment = Diamond(clazztype.tsym);
2961                         log.error(tree.clazz.pos(),
2962                                 Errors.CantApplyDiamond1(
2963                                         fragment,
2964                                         invalidDiamondArgs.size() > 1 ?
2965                                                 DiamondInvalidArgs(invalidDiamondArgs, fragment) :
2966                                                 DiamondInvalidArg(invalidDiamondArgs, fragment)));
2967                     }
2968                     // For <>(){}, inferred types must also be accessible.
2969                     for (Type t : clazztype.getTypeArguments()) {
2970                         rs.checkAccessibleType(env, t);
2971                     }
2972                 }
2973 
2974                 // If we already errored, be careful to avoid a further avalanche. ErrorType answers
2975                 // false for isInterface call even when the original type is an interface.
2976                 boolean implementing = clazztype.tsym.isInterface() ||
2977                         clazztype.isErroneous() && !clazztype.getOriginalType().hasTag(NONE) &&
2978                         clazztype.getOriginalType().tsym.isInterface();
2979 
2980                 if (implementing) {
2981                     cdef.implementing = List.of(clazz);
2982                 } else {
2983                     cdef.extending = clazz;
2984                 }
2985 
2986                 if (resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.CHECK &&
2987                     rs.isSerializable(clazztype)) {
2988                     localEnv.info.isSerializable = true;
2989                 }
2990 
2991                 attribStat(cdef, localEnv);
2992 
2993                 List<Type> finalargtypes;
2994                 // If an outer instance is given,
2995                 // prefix it to the constructor arguments
2996                 // and delete it from the new expression
2997                 if (tree.encl != null && !clazztype.tsym.isInterface()) {
2998                     finalargtypes = argtypes.prepend(tree.encl.type);
2999                 } else {
3000                     finalargtypes = argtypes;
3001                 }
3002 
3003                 // Reassign clazztype and recompute constructor. As this necessarily involves
3004                 // another attribution pass for deferred types in the case of <>, replicate
3005                 // them. Original arguments have right decorations already.
3006                 if (isDiamond && pkind.contains(KindSelector.POLY)) {
3007                     finalargtypes = finalargtypes.map(deferredAttr.deferredCopier);
3008                 }
3009 
3010                 clazztype = clazztype.hasTag(ERROR) ? types.createErrorType(cdef.sym.type)
3011                                                     : cdef.sym.type;
3012                 Symbol sym = tree.constructor = rs.resolveConstructor(
3013                         tree.pos(), localEnv, clazztype, finalargtypes, typeargtypes);
3014                 Assert.check(!sym.kind.isResolutionError());
3015                 tree.constructor = sym;
3016                 tree.constructorType = checkId(tree,
3017                         clazztype,
3018                         tree.constructor,
3019                         localEnv,
3020                         new ResultInfo(pkind, newMethodTemplate(syms.voidType, finalargtypes, typeargtypes), CheckMode.NO_TREE_UPDATE));
3021             }
3022             Type owntype = (tree.constructor != null && tree.constructor.kind == MTH) ?
3023                                 clazztype : types.createErrorType(tree.type);
3024             result = check(tree, owntype, KindSelector.VAL, resultInfo.dup(CheckMode.NO_INFERENCE_HOOK));
3025             chk.validate(tree.typeargs, localEnv);
3026         }
3027 
3028         CheckContext diamondContext(JCNewClass clazz, TypeSymbol tsym, CheckContext checkContext) {
3029             return new Check.NestedCheckContext(checkContext) {
3030                 @Override
3031                 public void report(DiagnosticPosition _unused, JCDiagnostic details) {
3032                     enclosingContext.report(clazz.clazz,
3033                             diags.fragment(Fragments.CantApplyDiamond1(Fragments.Diamond(tsym), details)));
3034                 }
3035             };
3036         }
3037 
3038     /** Make an attributed null check tree.
3039      */
3040     public JCExpression makeNullCheck(JCExpression arg) {
3041         // optimization: new Outer() can never be null; skip null check
3042         if (arg.getTag() == NEWCLASS)
3043             return arg;
3044         // optimization: X.this is never null; skip null check
3045         Name name = TreeInfo.name(arg);
3046         if (name == names._this || name == names._super) return arg;
3047 
3048         JCTree.Tag optag = NULLCHK;
3049         JCUnary tree = make.at(arg.pos).Unary(optag, arg);
3050         tree.operator = operators.resolveUnary(arg, optag, arg.type);
3051         tree.type = arg.type;
3052         return tree;
3053     }
3054 
3055     public void visitNewArray(JCNewArray tree) {
3056         Type owntype = types.createErrorType(tree.type);
3057         Env<AttrContext> localEnv = env.dup(tree);
3058         Type elemtype;
3059         if (tree.elemtype != null) {
3060             elemtype = attribType(tree.elemtype, localEnv);
3061             chk.validate(tree.elemtype, localEnv);
3062             owntype = elemtype;
3063             for (List<JCExpression> l = tree.dims; l.nonEmpty(); l = l.tail) {
3064                 attribExpr(l.head, localEnv, syms.intType);
3065                 owntype = new ArrayType(owntype, syms.arrayClass);
3066             }
3067         } else {
3068             // we are seeing an untyped aggregate { ... }
3069             // this is allowed only if the prototype is an array
3070             if (pt().hasTag(ARRAY)) {
3071                 elemtype = types.elemtype(pt());
3072             } else {
3073                 if (!pt().hasTag(ERROR) &&
3074                         (env.info.enclVar == null || !env.info.enclVar.type.isErroneous())) {
3075                     log.error(tree.pos(),
3076                               Errors.IllegalInitializerForType(pt()));
3077                 }
3078                 elemtype = types.createErrorType(pt());
3079             }
3080         }
3081         if (tree.elems != null) {
3082             attribExprs(tree.elems, localEnv, elemtype);
3083             owntype = new ArrayType(elemtype, syms.arrayClass);
3084         }
3085         if (!types.isReifiable(elemtype))
3086             log.error(tree.pos(), Errors.GenericArrayCreation);
3087         result = check(tree, owntype, KindSelector.VAL, resultInfo);
3088     }
3089 
3090     /*
3091      * A lambda expression can only be attributed when a target-type is available.
3092      * In addition, if the target-type is that of a functional interface whose
3093      * descriptor contains inference variables in argument position the lambda expression
3094      * is 'stuck' (see DeferredAttr).
3095      */
3096     @Override
3097     public void visitLambda(final JCLambda that) {
3098         boolean wrongContext = false;
3099         if (pt().isErroneous() || (pt().hasTag(NONE) && pt() != Type.recoveryType)) {
3100             if (pt().hasTag(NONE) && (env.info.enclVar == null || !env.info.enclVar.type.isErroneous())) {
3101                 //lambda only allowed in assignment or method invocation/cast context
3102                 log.error(that.pos(), Errors.UnexpectedLambda);
3103             }
3104             resultInfo = recoveryInfo;
3105             wrongContext = true;
3106         }
3107         //create an environment for attribution of the lambda expression
3108         final Env<AttrContext> localEnv = lambdaEnv(that, env);
3109         boolean needsRecovery =
3110                 resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.CHECK;
3111         try {
3112             if (needsRecovery && rs.isSerializable(pt())) {
3113                 localEnv.info.isSerializable = true;
3114                 localEnv.info.isSerializableLambda = true;
3115             }
3116             List<Type> explicitParamTypes = null;
3117             if (that.paramKind == JCLambda.ParameterKind.EXPLICIT) {
3118                 //attribute lambda parameters
3119                 attribStats(that.params, localEnv);
3120                 explicitParamTypes = TreeInfo.types(that.params);
3121             }
3122 
3123             TargetInfo targetInfo = getTargetInfo(that, resultInfo, explicitParamTypes);
3124             Type currentTarget = targetInfo.target;
3125             Type lambdaType = targetInfo.descriptor;
3126 
3127             if (currentTarget.isErroneous()) {
3128                 result = that.type = currentTarget;
3129                 return;
3130             }
3131 
3132             setFunctionalInfo(localEnv, that, pt(), lambdaType, currentTarget, resultInfo.checkContext);
3133 
3134             if (lambdaType.hasTag(FORALL)) {
3135                 //lambda expression target desc cannot be a generic method
3136                 Fragment msg = Fragments.InvalidGenericLambdaTarget(lambdaType,
3137                                                                     kindName(currentTarget.tsym),
3138                                                                     currentTarget.tsym);
3139                 resultInfo.checkContext.report(that, diags.fragment(msg));
3140                 result = that.type = types.createErrorType(pt());
3141                 return;
3142             }
3143 
3144             if (that.paramKind == JCLambda.ParameterKind.IMPLICIT) {
3145                 //add param type info in the AST
3146                 List<Type> actuals = lambdaType.getParameterTypes();
3147                 List<JCVariableDecl> params = that.params;
3148 
3149                 boolean arityMismatch = false;
3150 
3151                 while (params.nonEmpty()) {
3152                     if (actuals.isEmpty()) {
3153                         //not enough actuals to perform lambda parameter inference
3154                         arityMismatch = true;
3155                     }
3156                     //reset previously set info
3157                     Type argType = arityMismatch ?
3158                             syms.errType :
3159                             actuals.head;
3160                     if (params.head.isImplicitlyTyped()) {
3161                         setSyntheticVariableType(params.head, argType);
3162                     }
3163                     params.head.sym = null;
3164                     actuals = actuals.isEmpty() ?
3165                             actuals :
3166                             actuals.tail;
3167                     params = params.tail;
3168                 }
3169 
3170                 //attribute lambda parameters
3171                 attribStats(that.params, localEnv);
3172 
3173                 if (arityMismatch) {
3174                     resultInfo.checkContext.report(that, diags.fragment(Fragments.IncompatibleArgTypesInLambda));
3175                         result = that.type = types.createErrorType(currentTarget);
3176                         return;
3177                 }
3178             }
3179 
3180             //from this point on, no recovery is needed; if we are in assignment context
3181             //we will be able to attribute the whole lambda body, regardless of errors;
3182             //if we are in a 'check' method context, and the lambda is not compatible
3183             //with the target-type, it will be recovered anyway in Attr.checkId
3184             needsRecovery = false;
3185 
3186             ResultInfo bodyResultInfo = localEnv.info.returnResult =
3187                     lambdaBodyResult(that, lambdaType, resultInfo);
3188 
3189             if (that.getBodyKind() == JCLambda.BodyKind.EXPRESSION) {
3190                 attribTree(that.getBody(), localEnv, bodyResultInfo);
3191             } else {
3192                 JCBlock body = (JCBlock)that.body;
3193                 if (body == breakTree &&
3194                         resultInfo.checkContext.deferredAttrContext().mode == AttrMode.CHECK) {
3195                     breakTreeFound(copyEnv(localEnv));
3196                 }
3197                 attribStats(body.stats, localEnv);
3198             }
3199 
3200             result = check(that, currentTarget, KindSelector.VAL, resultInfo);
3201 
3202             boolean isSpeculativeRound =
3203                     resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.SPECULATIVE;
3204 
3205             preFlow(that);
3206             flow.analyzeLambda(env, that, make, isSpeculativeRound);
3207 
3208             that.type = currentTarget; //avoids recovery at this stage
3209             checkLambdaCompatible(that, lambdaType, resultInfo.checkContext);
3210 
3211             if (!isSpeculativeRound) {
3212                 //add thrown types as bounds to the thrown types free variables if needed:
3213                 if (resultInfo.checkContext.inferenceContext().free(lambdaType.getThrownTypes())) {
3214                     List<Type> inferredThrownTypes = flow.analyzeLambdaThrownTypes(env, that, make);
3215                     if(!checkExConstraints(inferredThrownTypes, lambdaType.getThrownTypes(), resultInfo.checkContext.inferenceContext())) {
3216                         log.error(that, Errors.IncompatibleThrownTypesInMref(lambdaType.getThrownTypes()));
3217                     }
3218                 }
3219 
3220                 checkAccessibleTypes(that, localEnv, resultInfo.checkContext.inferenceContext(), lambdaType, currentTarget);
3221             }
3222             result = wrongContext ? that.type = types.createErrorType(pt())
3223                                   : check(that, currentTarget, KindSelector.VAL, resultInfo);
3224         } catch (Types.FunctionDescriptorLookupError ex) {
3225             JCDiagnostic cause = ex.getDiagnostic();
3226             resultInfo.checkContext.report(that, cause);
3227             result = that.type = types.createErrorType(pt());
3228             return;
3229         } catch (CompletionFailure cf) {
3230             chk.completionError(that.pos(), cf);
3231         } catch (Throwable t) {
3232             //when an unexpected exception happens, avoid attempts to attribute the same tree again
3233             //as that would likely cause the same exception again.
3234             needsRecovery = false;
3235             throw t;
3236         } finally {
3237             localEnv.info.scope.leave();
3238             if (needsRecovery) {
3239                 Type prevResult = result;
3240                 try {
3241                     attribTree(that, env, recoveryInfo);
3242                 } finally {
3243                     if (result == Type.recoveryType) {
3244                         result = prevResult;
3245                     }
3246                 }
3247             }
3248         }
3249     }
3250     //where
3251         class TargetInfo {
3252             Type target;
3253             Type descriptor;
3254 
3255             public TargetInfo(Type target, Type descriptor) {
3256                 this.target = target;
3257                 this.descriptor = descriptor;
3258             }
3259         }
3260 
3261         TargetInfo getTargetInfo(JCPolyExpression that, ResultInfo resultInfo, List<Type> explicitParamTypes) {
3262             Type lambdaType;
3263             Type currentTarget = resultInfo.pt;
3264             if (resultInfo.pt != Type.recoveryType) {
3265                 /* We need to adjust the target. If the target is an
3266                  * intersection type, for example: SAM & I1 & I2 ...
3267                  * the target will be updated to SAM
3268                  */
3269                 currentTarget = targetChecker.visit(currentTarget, that);
3270                 if (!currentTarget.isIntersection()) {
3271                     if (explicitParamTypes != null) {
3272                         currentTarget = infer.instantiateFunctionalInterface(that,
3273                                 currentTarget, explicitParamTypes, resultInfo.checkContext);
3274                     }
3275                     currentTarget = types.removeWildcards(currentTarget);
3276                     lambdaType = types.findDescriptorType(currentTarget);
3277                 } else {
3278                     IntersectionClassType ict = (IntersectionClassType)currentTarget;
3279                     ListBuffer<Type> components = new ListBuffer<>();
3280                     for (Type bound : ict.getExplicitComponents()) {
3281                         if (explicitParamTypes != null) {
3282                             try {
3283                                 bound = infer.instantiateFunctionalInterface(that,
3284                                         bound, explicitParamTypes, resultInfo.checkContext);
3285                             } catch (FunctionDescriptorLookupError t) {
3286                                 // do nothing
3287                             }
3288                         }
3289                         bound = types.removeWildcards(bound);
3290                         components.add(bound);
3291                     }
3292                     currentTarget = types.makeIntersectionType(components.toList());
3293                     currentTarget.tsym.flags_field |= INTERFACE;
3294                     lambdaType = types.findDescriptorType(currentTarget);
3295                 }
3296 
3297             } else {
3298                 currentTarget = Type.recoveryType;
3299                 lambdaType = fallbackDescriptorType(that);
3300             }
3301             if (that.hasTag(LAMBDA) && lambdaType.hasTag(FORALL)) {
3302                 //lambda expression target desc cannot be a generic method
3303                 Fragment msg = Fragments.InvalidGenericLambdaTarget(lambdaType,
3304                                                                     kindName(currentTarget.tsym),
3305                                                                     currentTarget.tsym);
3306                 resultInfo.checkContext.report(that, diags.fragment(msg));
3307                 currentTarget = types.createErrorType(pt());
3308             }
3309             return new TargetInfo(currentTarget, lambdaType);
3310         }
3311 
3312         void preFlow(JCLambda tree) {
3313             attrRecover.doRecovery();
3314             new PostAttrAnalyzer() {
3315                 @Override
3316                 public void scan(JCTree tree) {
3317                     if (tree == null ||
3318                             (tree.type != null &&
3319                             tree.type == Type.stuckType)) {
3320                         //don't touch stuck expressions!
3321                         return;
3322                     }
3323                     super.scan(tree);
3324                 }
3325 
3326                 @Override
3327                 public void visitClassDef(JCClassDecl that) {
3328                     // or class declaration trees!
3329                 }
3330 
3331                 public void visitLambda(JCLambda that) {
3332                     // or lambda expressions!
3333                 }
3334             }.scan(tree.body);
3335         }
3336 
3337         Types.MapVisitor<DiagnosticPosition> targetChecker = new Types.MapVisitor<DiagnosticPosition>() {
3338 
3339             @Override
3340             public Type visitClassType(ClassType t, DiagnosticPosition pos) {
3341                 return t.isIntersection() ?
3342                         visitIntersectionClassType((IntersectionClassType)t, pos) : t;
3343             }
3344 
3345             public Type visitIntersectionClassType(IntersectionClassType ict, DiagnosticPosition pos) {
3346                 types.findDescriptorSymbol(makeNotionalInterface(ict, pos));
3347                 return ict;
3348             }
3349 
3350             private TypeSymbol makeNotionalInterface(IntersectionClassType ict, DiagnosticPosition pos) {
3351                 ListBuffer<Type> targs = new ListBuffer<>();
3352                 ListBuffer<Type> supertypes = new ListBuffer<>();
3353                 for (Type i : ict.interfaces_field) {
3354                     if (i.isParameterized()) {
3355                         targs.appendList(i.tsym.type.allparams());
3356                     }
3357                     supertypes.append(i.tsym.type);
3358                 }
3359                 IntersectionClassType notionalIntf = types.makeIntersectionType(supertypes.toList());
3360                 notionalIntf.allparams_field = targs.toList();
3361                 notionalIntf.tsym.flags_field |= INTERFACE;
3362                 return notionalIntf.tsym;
3363             }
3364         };
3365 
3366         private Type fallbackDescriptorType(JCExpression tree) {
3367             switch (tree.getTag()) {
3368                 case LAMBDA:
3369                     JCLambda lambda = (JCLambda)tree;
3370                     List<Type> argtypes = List.nil();
3371                     for (JCVariableDecl param : lambda.params) {
3372                         argtypes = param.vartype != null && param.vartype.type != null ?
3373                                 argtypes.append(param.vartype.type) :
3374                                 argtypes.append(syms.errType);
3375                     }
3376                     return new MethodType(argtypes, Type.recoveryType,
3377                             List.of(syms.throwableType), syms.methodClass);
3378                 case REFERENCE:
3379                     return new MethodType(List.nil(), Type.recoveryType,
3380                             List.of(syms.throwableType), syms.methodClass);
3381                 default:
3382                     Assert.error("Cannot get here!");
3383             }
3384             return null;
3385         }
3386 
3387         private void checkAccessibleTypes(final DiagnosticPosition pos, final Env<AttrContext> env,
3388                 final InferenceContext inferenceContext, final Type... ts) {
3389             checkAccessibleTypes(pos, env, inferenceContext, List.from(ts));
3390         }
3391 
3392         private void checkAccessibleTypes(final DiagnosticPosition pos, final Env<AttrContext> env,
3393                 final InferenceContext inferenceContext, final List<Type> ts) {
3394             if (inferenceContext.free(ts)) {
3395                 inferenceContext.addFreeTypeListener(ts,
3396                         solvedContext -> checkAccessibleTypes(pos, env, solvedContext, solvedContext.asInstTypes(ts)));
3397             } else {
3398                 for (Type t : ts) {
3399                     rs.checkAccessibleType(env, t);
3400                 }
3401             }
3402         }
3403 
3404         /**
3405          * Lambda/method reference have a special check context that ensures
3406          * that i.e. a lambda return type is compatible with the expected
3407          * type according to both the inherited context and the assignment
3408          * context.
3409          */
3410         class FunctionalReturnContext extends Check.NestedCheckContext {
3411 
3412             FunctionalReturnContext(CheckContext enclosingContext) {
3413                 super(enclosingContext);
3414             }
3415 
3416             @Override
3417             public boolean compatible(Type found, Type req, Warner warn) {
3418                 //return type must be compatible in both current context and assignment context
3419                 return chk.basicHandler.compatible(inferenceContext().asUndetVar(found), inferenceContext().asUndetVar(req), warn);
3420             }
3421 
3422             @Override
3423             public void report(DiagnosticPosition pos, JCDiagnostic details) {
3424                 enclosingContext.report(pos, diags.fragment(Fragments.IncompatibleRetTypeInLambda(details)));
3425             }
3426         }
3427 
3428         class ExpressionLambdaReturnContext extends FunctionalReturnContext {
3429 
3430             JCExpression expr;
3431             boolean expStmtExpected;
3432 
3433             ExpressionLambdaReturnContext(JCExpression expr, CheckContext enclosingContext) {
3434                 super(enclosingContext);
3435                 this.expr = expr;
3436             }
3437 
3438             @Override
3439             public void report(DiagnosticPosition pos, JCDiagnostic details) {
3440                 if (expStmtExpected) {
3441                     enclosingContext.report(pos, diags.fragment(Fragments.StatExprExpected));
3442                 } else {
3443                     super.report(pos, details);
3444                 }
3445             }
3446 
3447             @Override
3448             public boolean compatible(Type found, Type req, Warner warn) {
3449                 //a void return is compatible with an expression statement lambda
3450                 if (req.hasTag(VOID)) {
3451                     expStmtExpected = true;
3452                     return TreeInfo.isExpressionStatement(expr);
3453                 } else {
3454                     return super.compatible(found, req, warn);
3455                 }
3456             }
3457         }
3458 
3459         ResultInfo lambdaBodyResult(JCLambda that, Type descriptor, ResultInfo resultInfo) {
3460             FunctionalReturnContext funcContext = that.getBodyKind() == JCLambda.BodyKind.EXPRESSION ?
3461                     new ExpressionLambdaReturnContext((JCExpression)that.getBody(), resultInfo.checkContext) :
3462                     new FunctionalReturnContext(resultInfo.checkContext);
3463 
3464             return descriptor.getReturnType() == Type.recoveryType ?
3465                     recoveryInfo :
3466                     new ResultInfo(KindSelector.VAL,
3467                             descriptor.getReturnType(), funcContext);
3468         }
3469 
3470         /**
3471         * Lambda compatibility. Check that given return types, thrown types, parameter types
3472         * are compatible with the expected functional interface descriptor. This means that:
3473         * (i) parameter types must be identical to those of the target descriptor; (ii) return
3474         * types must be compatible with the return type of the expected descriptor.
3475         */
3476         void checkLambdaCompatible(JCLambda tree, Type descriptor, CheckContext checkContext) {
3477             Type returnType = checkContext.inferenceContext().asUndetVar(descriptor.getReturnType());
3478 
3479             //return values have already been checked - but if lambda has no return
3480             //values, we must ensure that void/value compatibility is correct;
3481             //this amounts at checking that, if a lambda body can complete normally,
3482             //the descriptor's return type must be void
3483             if (tree.getBodyKind() == JCLambda.BodyKind.STATEMENT && tree.canCompleteNormally &&
3484                     !returnType.hasTag(VOID) && returnType != Type.recoveryType) {
3485                 Fragment msg =
3486                         Fragments.IncompatibleRetTypeInLambda(Fragments.MissingRetVal(returnType));
3487                 checkContext.report(tree,
3488                                     diags.fragment(msg));
3489             }
3490 
3491             List<Type> argTypes = checkContext.inferenceContext().asUndetVars(descriptor.getParameterTypes());
3492             if (!types.isSameTypes(argTypes, TreeInfo.types(tree.params))) {
3493                 checkContext.report(tree, diags.fragment(Fragments.IncompatibleArgTypesInLambda));
3494             }
3495         }
3496 
3497         /* Map to hold 'fake' clinit methods. If a lambda is used to initialize a
3498          * static field and that lambda has type annotations, these annotations will
3499          * also be stored at these fake clinit methods.
3500          *
3501          * LambdaToMethod also use fake clinit methods so they can be reused.
3502          * Also as LTM is a phase subsequent to attribution, the methods from
3503          * clinits can be safely removed by LTM to save memory.
3504          */
3505         private Map<ClassSymbol, MethodSymbol> clinits = new HashMap<>();
3506 
3507         public MethodSymbol removeClinit(ClassSymbol sym) {
3508             return clinits.remove(sym);
3509         }
3510 
3511         /* This method returns an environment to be used to attribute a lambda
3512          * expression.
3513          *
3514          * The owner of this environment is a method symbol. If the current owner
3515          * is not a method, for example if the lambda is used to initialize
3516          * a field, then if the field is:
3517          *
3518          * - an instance field, we use the first constructor.
3519          * - a static field, we create a fake clinit method.
3520          */
3521         public Env<AttrContext> lambdaEnv(JCLambda that, Env<AttrContext> env) {
3522             Env<AttrContext> lambdaEnv;
3523             Symbol owner = env.info.scope.owner;
3524             if (owner.kind == VAR && owner.owner.kind == TYP) {
3525                 //field initializer
3526                 ClassSymbol enclClass = owner.enclClass();
3527                 Symbol newScopeOwner = env.info.scope.owner;
3528                 /* if the field isn't static, then we can get the first constructor
3529                  * and use it as the owner of the environment. This is what
3530                  * LTM code is doing to look for type annotations so we are fine.
3531                  */
3532                 if ((owner.flags() & STATIC) == 0) {
3533                     for (Symbol s : enclClass.members_field.getSymbolsByName(names.init)) {
3534                         newScopeOwner = s;
3535                         break;
3536                     }
3537                 } else {
3538                     /* if the field is static then we need to create a fake clinit
3539                      * method, this method can later be reused by LTM.
3540                      */
3541                     MethodSymbol clinit = clinits.get(enclClass);
3542                     if (clinit == null) {
3543                         Type clinitType = new MethodType(List.nil(),
3544                                 syms.voidType, List.nil(), syms.methodClass);
3545                         clinit = new MethodSymbol(STATIC | SYNTHETIC | PRIVATE,
3546                                 names.clinit, clinitType, enclClass);
3547                         clinit.params = List.nil();
3548                         clinits.put(enclClass, clinit);
3549                     }
3550                     newScopeOwner = clinit;
3551                 }
3552                 lambdaEnv = env.dup(that, env.info.dup(env.info.scope.dupUnshared(newScopeOwner)));
3553             } else {
3554                 lambdaEnv = env.dup(that, env.info.dup(env.info.scope.dup()));
3555             }
3556             lambdaEnv.info.yieldResult = null;
3557             lambdaEnv.info.isLambda = true;
3558             return lambdaEnv;
3559         }
3560 
3561     @Override
3562     public void visitReference(final JCMemberReference that) {
3563         if (pt().isErroneous() || (pt().hasTag(NONE) && pt() != Type.recoveryType)) {
3564             if (pt().hasTag(NONE) && (env.info.enclVar == null || !env.info.enclVar.type.isErroneous())) {
3565                 //method reference only allowed in assignment or method invocation/cast context
3566                 log.error(that.pos(), Errors.UnexpectedMref);
3567             }
3568             result = that.type = types.createErrorType(pt());
3569             return;
3570         }
3571         final Env<AttrContext> localEnv = env.dup(that);
3572         try {
3573             //attribute member reference qualifier - if this is a constructor
3574             //reference, the expected kind must be a type
3575             Type exprType = attribTree(that.expr, env, memberReferenceQualifierResult(that));
3576 
3577             if (that.getMode() == JCMemberReference.ReferenceMode.NEW) {
3578                 exprType = chk.checkConstructorRefType(that.expr, exprType);
3579                 if (!exprType.isErroneous() &&
3580                     exprType.isRaw() &&
3581                     that.typeargs != null) {
3582                     log.error(that.expr.pos(),
3583                               Errors.InvalidMref(Kinds.kindName(that.getMode()),
3584                                                  Fragments.MrefInferAndExplicitParams));
3585                     exprType = types.createErrorType(exprType);
3586                 }
3587             }
3588 
3589             if (exprType.isErroneous()) {
3590                 //if the qualifier expression contains problems,
3591                 //give up attribution of method reference
3592                 result = that.type = exprType;
3593                 return;
3594             }
3595 
3596             if (TreeInfo.isStaticSelector(that.expr, names)) {
3597                 //if the qualifier is a type, validate it; raw warning check is
3598                 //omitted as we don't know at this stage as to whether this is a
3599                 //raw selector (because of inference)
3600                 chk.validate(that.expr, env, false);
3601             } else {
3602                 Symbol lhsSym = TreeInfo.symbol(that.expr);
3603                 localEnv.info.selectSuper = lhsSym != null && lhsSym.name == names._super;
3604             }
3605             //attrib type-arguments
3606             List<Type> typeargtypes = List.nil();
3607             if (that.typeargs != null) {
3608                 typeargtypes = attribTypes(that.typeargs, localEnv);
3609             }
3610 
3611             boolean isTargetSerializable =
3612                     resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.CHECK &&
3613                     rs.isSerializable(pt());
3614             TargetInfo targetInfo = getTargetInfo(that, resultInfo, null);
3615             Type currentTarget = targetInfo.target;
3616             Type desc = targetInfo.descriptor;
3617 
3618             setFunctionalInfo(localEnv, that, pt(), desc, currentTarget, resultInfo.checkContext);
3619             List<Type> argtypes = desc.getParameterTypes();
3620             Resolve.MethodCheck referenceCheck = rs.resolveMethodCheck;
3621 
3622             if (resultInfo.checkContext.inferenceContext().free(argtypes)) {
3623                 referenceCheck = rs.new MethodReferenceCheck(resultInfo.checkContext.inferenceContext());
3624             }
3625 
3626             Pair<Symbol, Resolve.ReferenceLookupHelper> refResult = null;
3627             List<Type> saved_undet = resultInfo.checkContext.inferenceContext().save();
3628             try {
3629                 refResult = rs.resolveMemberReference(localEnv, that, that.expr.type,
3630                         that.name, argtypes, typeargtypes, targetInfo.descriptor, referenceCheck,
3631                         resultInfo.checkContext.inferenceContext(), rs.basicReferenceChooser);
3632             } finally {
3633                 resultInfo.checkContext.inferenceContext().rollback(saved_undet);
3634             }
3635 
3636             Symbol refSym = refResult.fst;
3637             Resolve.ReferenceLookupHelper lookupHelper = refResult.snd;
3638 
3639             /** this switch will need to go away and be replaced by the new RESOLUTION_TARGET testing
3640              *  JDK-8075541
3641              */
3642             if (refSym.kind != MTH) {
3643                 boolean targetError;
3644                 switch (refSym.kind) {
3645                     case ABSENT_MTH:
3646                     case MISSING_ENCL:
3647                         targetError = false;
3648                         break;
3649                     case WRONG_MTH:
3650                     case WRONG_MTHS:
3651                     case AMBIGUOUS:
3652                     case HIDDEN:
3653                     case STATICERR:
3654                         targetError = true;
3655                         break;
3656                     default:
3657                         Assert.error("unexpected result kind " + refSym.kind);
3658                         targetError = false;
3659                 }
3660 
3661                 JCDiagnostic detailsDiag = ((Resolve.ResolveError)refSym.baseSymbol())
3662                         .getDiagnostic(JCDiagnostic.DiagnosticType.FRAGMENT,
3663                                 that, exprType.tsym, exprType, that.name, argtypes, typeargtypes);
3664 
3665                 JCDiagnostic diag = diags.create(log.currentSource(), that,
3666                         targetError ?
3667                             Fragments.InvalidMref(Kinds.kindName(that.getMode()), detailsDiag) :
3668                             Errors.InvalidMref(Kinds.kindName(that.getMode()), detailsDiag));
3669 
3670                 if (targetError && currentTarget == Type.recoveryType) {
3671                     //a target error doesn't make sense during recovery stage
3672                     //as we don't know what actual parameter types are
3673                     result = that.type = currentTarget;
3674                     return;
3675                 } else {
3676                     if (targetError) {
3677                         resultInfo.checkContext.report(that, diag);
3678                     } else {
3679                         log.report(diag);
3680                     }
3681                     result = that.type = types.createErrorType(currentTarget);
3682                     return;
3683                 }
3684             }
3685 
3686             that.sym = refSym.isConstructor() ? refSym.baseSymbol() : refSym;
3687             that.kind = lookupHelper.referenceKind(that.sym);
3688             that.ownerAccessible = rs.isAccessible(localEnv, that.sym.enclClass());
3689 
3690             if (desc.getReturnType() == Type.recoveryType) {
3691                 // stop here
3692                 result = that.type = currentTarget;
3693                 return;
3694             }
3695 
3696             if (!env.info.attributionMode.isSpeculative && that.getMode() == JCMemberReference.ReferenceMode.NEW) {
3697                 Type enclosingType = exprType.getEnclosingType();
3698                 if (enclosingType != null && enclosingType.hasTag(CLASS)) {
3699                     // Check for the existence of an appropriate outer instance
3700                     rs.resolveImplicitThis(that.pos(), env, exprType);
3701                 }
3702             }
3703 
3704             if (resultInfo.checkContext.deferredAttrContext().mode == AttrMode.CHECK) {
3705 
3706                 if (that.getMode() == ReferenceMode.INVOKE &&
3707                         TreeInfo.isStaticSelector(that.expr, names) &&
3708                         that.kind.isUnbound() &&
3709                         lookupHelper.site.isRaw()) {
3710                     chk.checkRaw(that.expr, localEnv);
3711                 }
3712 
3713                 if (that.sym.isStatic() && TreeInfo.isStaticSelector(that.expr, names) &&
3714                         exprType.getTypeArguments().nonEmpty()) {
3715                     //static ref with class type-args
3716                     log.error(that.expr.pos(),
3717                               Errors.InvalidMref(Kinds.kindName(that.getMode()),
3718                                                  Fragments.StaticMrefWithTargs));
3719                     result = that.type = types.createErrorType(currentTarget);
3720                     return;
3721                 }
3722 
3723                 if (!refSym.isStatic() && that.kind == JCMemberReference.ReferenceKind.SUPER) {
3724                     // Check that super-qualified symbols are not abstract (JLS)
3725                     rs.checkNonAbstract(that.pos(), that.sym);
3726                 }
3727 
3728                 if (isTargetSerializable) {
3729                     chk.checkAccessFromSerializableElement(that, true);
3730                 }
3731             }
3732 
3733             ResultInfo checkInfo =
3734                     resultInfo.dup(newMethodTemplate(
3735                         desc.getReturnType().hasTag(VOID) ? Type.noType : desc.getReturnType(),
3736                         that.kind.isUnbound() ? argtypes.tail : argtypes, typeargtypes),
3737                         new FunctionalReturnContext(resultInfo.checkContext), CheckMode.NO_TREE_UPDATE);
3738 
3739             Type refType = checkId(that, lookupHelper.site, refSym, localEnv, checkInfo);
3740 
3741             if (that.kind.isUnbound() &&
3742                     resultInfo.checkContext.inferenceContext().free(argtypes.head)) {
3743                 //re-generate inference constraints for unbound receiver
3744                 if (!types.isSubtype(resultInfo.checkContext.inferenceContext().asUndetVar(argtypes.head), exprType)) {
3745                     //cannot happen as this has already been checked - we just need
3746                     //to regenerate the inference constraints, as that has been lost
3747                     //as a result of the call to inferenceContext.save()
3748                     Assert.error("Can't get here");
3749                 }
3750             }
3751 
3752             if (!refType.isErroneous()) {
3753                 refType = types.createMethodTypeWithReturn(refType,
3754                         adjustMethodReturnType(refSym, lookupHelper.site, that.name, checkInfo.pt.getParameterTypes(), refType.getReturnType()));
3755             }
3756 
3757             //go ahead with standard method reference compatibility check - note that param check
3758             //is a no-op (as this has been taken care during method applicability)
3759             boolean isSpeculativeRound =
3760                     resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.SPECULATIVE;
3761 
3762             that.type = currentTarget; //avoids recovery at this stage
3763             checkReferenceCompatible(that, desc, refType, resultInfo.checkContext, isSpeculativeRound);
3764             if (!isSpeculativeRound) {
3765                 checkAccessibleTypes(that, localEnv, resultInfo.checkContext.inferenceContext(), desc, currentTarget);
3766             }
3767             result = check(that, currentTarget, KindSelector.VAL, resultInfo);
3768         } catch (Types.FunctionDescriptorLookupError ex) {
3769             JCDiagnostic cause = ex.getDiagnostic();
3770             resultInfo.checkContext.report(that, cause);
3771             result = that.type = types.createErrorType(pt());
3772             return;
3773         }
3774     }
3775     //where
3776         ResultInfo memberReferenceQualifierResult(JCMemberReference tree) {
3777             //if this is a constructor reference, the expected kind must be a type
3778             return new ResultInfo(tree.getMode() == ReferenceMode.INVOKE ?
3779                                   KindSelector.VAL_TYP : KindSelector.TYP,
3780                                   Type.noType);
3781         }
3782 
3783 
3784     @SuppressWarnings("fallthrough")
3785     void checkReferenceCompatible(JCMemberReference tree, Type descriptor, Type refType, CheckContext checkContext, boolean speculativeAttr) {
3786         InferenceContext inferenceContext = checkContext.inferenceContext();
3787         Type returnType = inferenceContext.asUndetVar(descriptor.getReturnType());
3788 
3789         Type resType;
3790         switch (tree.getMode()) {
3791             case NEW:
3792                 if (!tree.expr.type.isRaw()) {
3793                     resType = tree.expr.type;
3794                     break;
3795                 }
3796             default:
3797                 resType = refType.getReturnType();
3798         }
3799 
3800         Type incompatibleReturnType = resType;
3801 
3802         if (returnType.hasTag(VOID)) {
3803             incompatibleReturnType = null;
3804         }
3805 
3806         if (!returnType.hasTag(VOID) && !resType.hasTag(VOID)) {
3807             if (resType.isErroneous() ||
3808                     new FunctionalReturnContext(checkContext).compatible(resType, returnType,
3809                             checkContext.checkWarner(tree, resType, returnType))) {
3810                 incompatibleReturnType = null;
3811             }
3812         }
3813 
3814         if (incompatibleReturnType != null) {
3815             Fragment msg =
3816                     Fragments.IncompatibleRetTypeInMref(Fragments.InconvertibleTypes(resType, descriptor.getReturnType()));
3817             checkContext.report(tree, diags.fragment(msg));
3818         } else {
3819             if (inferenceContext.free(refType)) {
3820                 // we need to wait for inference to finish and then replace inference vars in the referent type
3821                 inferenceContext.addFreeTypeListener(List.of(refType),
3822                         instantiatedContext -> {
3823                             tree.referentType = instantiatedContext.asInstType(refType);
3824                         });
3825             } else {
3826                 tree.referentType = refType;
3827             }
3828         }
3829 
3830         if (!speculativeAttr) {
3831             if (!checkExConstraints(refType.getThrownTypes(), descriptor.getThrownTypes(), inferenceContext)) {
3832                 log.error(tree, Errors.IncompatibleThrownTypesInMref(refType.getThrownTypes()));
3833             }
3834         }
3835     }
3836 
3837     boolean checkExConstraints(
3838             List<Type> thrownByFuncExpr,
3839             List<Type> thrownAtFuncType,
3840             InferenceContext inferenceContext) {
3841         /** 18.2.5: Otherwise, let E1, ..., En be the types in the function type's throws clause that
3842          *  are not proper types
3843          */
3844         List<Type> nonProperList = thrownAtFuncType.stream()
3845                 .filter(e -> inferenceContext.free(e)).collect(List.collector());
3846         List<Type> properList = thrownAtFuncType.diff(nonProperList);
3847 
3848         /** Let X1,...,Xm be the checked exception types that the lambda body can throw or
3849          *  in the throws clause of the invocation type of the method reference's compile-time
3850          *  declaration
3851          */
3852         List<Type> checkedList = thrownByFuncExpr.stream()
3853                 .filter(e -> chk.isChecked(e)).collect(List.collector());
3854 
3855         /** If n = 0 (the function type's throws clause consists only of proper types), then
3856          *  if there exists some i (1 <= i <= m) such that Xi is not a subtype of any proper type
3857          *  in the throws clause, the constraint reduces to false; otherwise, the constraint
3858          *  reduces to true
3859          */
3860         ListBuffer<Type> uncaughtByProperTypes = new ListBuffer<>();
3861         for (Type checked : checkedList) {
3862             boolean isSubtype = false;
3863             for (Type proper : properList) {
3864                 if (types.isSubtype(checked, proper)) {
3865                     isSubtype = true;
3866                     break;
3867                 }
3868             }
3869             if (!isSubtype) {
3870                 uncaughtByProperTypes.add(checked);
3871             }
3872         }
3873 
3874         if (nonProperList.isEmpty() && !uncaughtByProperTypes.isEmpty()) {
3875             return false;
3876         }
3877 
3878         /** If n > 0, the constraint reduces to a set of subtyping constraints:
3879          *  for all i (1 <= i <= m), if Xi is not a subtype of any proper type in the
3880          *  throws clause, then the constraints include, for all j (1 <= j <= n), <Xi <: Ej>
3881          */
3882         List<Type> nonProperAsUndet = inferenceContext.asUndetVars(nonProperList);
3883         uncaughtByProperTypes.forEach(checkedEx -> {
3884             nonProperAsUndet.forEach(nonProper -> {
3885                 types.isSubtype(checkedEx, nonProper);
3886             });
3887         });
3888 
3889         /** In addition, for all j (1 <= j <= n), the constraint reduces to the bound throws Ej
3890          */
3891         nonProperAsUndet.stream()
3892                 .filter(t -> t.hasTag(UNDETVAR))
3893                 .forEach(t -> ((UndetVar)t).setThrow());
3894         return true;
3895     }
3896 
3897     /**
3898      * Set functional type info on the underlying AST. Note: as the target descriptor
3899      * might contain inference variables, we might need to register an hook in the
3900      * current inference context.
3901      */
3902     private void setFunctionalInfo(final Env<AttrContext> env, final JCFunctionalExpression fExpr,
3903             final Type pt, final Type descriptorType, final Type primaryTarget, final CheckContext checkContext) {
3904         if (checkContext.inferenceContext().free(descriptorType)) {
3905             checkContext.inferenceContext().addFreeTypeListener(List.of(pt, descriptorType),
3906                     inferenceContext -> setFunctionalInfo(env, fExpr, pt, inferenceContext.asInstType(descriptorType),
3907                     inferenceContext.asInstType(primaryTarget), checkContext));
3908         } else {
3909             if (pt.hasTag(CLASS)) {
3910                 fExpr.target = primaryTarget;
3911             }
3912             if (checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.CHECK &&
3913                     pt != Type.recoveryType) {
3914                 //check that functional interface class is well-formed
3915                 try {
3916                     /* Types.makeFunctionalInterfaceClass() may throw an exception
3917                      * when it's executed post-inference. See the listener code
3918                      * above.
3919                      */
3920                     ClassSymbol csym = types.makeFunctionalInterfaceClass(env,
3921                             names.empty, fExpr.target, ABSTRACT);
3922                     if (csym != null) {
3923                         chk.checkImplementations(env.tree, csym, csym);
3924                         try {
3925                             //perform an additional functional interface check on the synthetic class,
3926                             //as there may be spurious errors for raw targets - because of existing issues
3927                             //with membership and inheritance (see JDK-8074570).
3928                             csym.flags_field |= INTERFACE;
3929                             types.findDescriptorType(csym.type);
3930                         } catch (FunctionDescriptorLookupError err) {
3931                             resultInfo.checkContext.report(fExpr,
3932                                     diags.fragment(Fragments.NoSuitableFunctionalIntfInst(fExpr.target)));
3933                         }
3934                     }
3935                 } catch (Types.FunctionDescriptorLookupError ex) {
3936                     JCDiagnostic cause = ex.getDiagnostic();
3937                     resultInfo.checkContext.report(env.tree, cause);
3938                 }
3939             }
3940         }
3941     }
3942 
3943     public void visitParens(JCParens tree) {
3944         Type owntype = attribTree(tree.expr, env, resultInfo);
3945         result = check(tree, owntype, pkind(), resultInfo);
3946         Symbol sym = TreeInfo.symbol(tree);
3947         if (sym != null && sym.kind.matches(KindSelector.TYP_PCK) && sym.kind != Kind.ERR)
3948             log.error(tree.pos(), Errors.IllegalParenthesizedExpression);
3949     }
3950 
3951     public void visitAssign(JCAssign tree) {
3952         Type owntype = attribTree(tree.lhs, env.dup(tree), varAssignmentInfo);
3953         Type capturedType = capture(owntype);
3954         attribExpr(tree.rhs, env, owntype);
3955         result = check(tree, capturedType, KindSelector.VAL, resultInfo);
3956     }
3957 
3958     public void visitAssignop(JCAssignOp tree) {
3959         // Attribute arguments.
3960         Type owntype = attribTree(tree.lhs, env, varAssignmentInfo);
3961         Type operand = attribExpr(tree.rhs, env);
3962         // Find operator.
3963         Symbol operator = tree.operator = operators.resolveBinary(tree, tree.getTag().noAssignOp(), owntype, operand);
3964         if (operator != operators.noOpSymbol &&
3965                 !owntype.isErroneous() &&
3966                 !operand.isErroneous()) {
3967             chk.checkDivZero(tree.rhs.pos(), operator, operand);
3968             chk.checkCastable(tree.rhs.pos(),
3969                               operator.type.getReturnType(),
3970                               owntype);
3971             chk.checkLossOfPrecision(tree.rhs.pos(), operand, owntype);
3972         }
3973         result = check(tree, owntype, KindSelector.VAL, resultInfo);
3974     }
3975 
3976     public void visitUnary(JCUnary tree) {
3977         // Attribute arguments.
3978         Type argtype = (tree.getTag().isIncOrDecUnaryOp())
3979             ? attribTree(tree.arg, env, varAssignmentInfo)
3980             : chk.checkNonVoid(tree.arg.pos(), attribExpr(tree.arg, env));
3981 
3982         // Find operator.
3983         OperatorSymbol operator = tree.operator = operators.resolveUnary(tree, tree.getTag(), argtype);
3984         Type owntype = types.createErrorType(tree.type);
3985         if (operator != operators.noOpSymbol &&
3986                 !argtype.isErroneous()) {
3987             owntype = (tree.getTag().isIncOrDecUnaryOp())
3988                 ? tree.arg.type
3989                 : operator.type.getReturnType();
3990             int opc = operator.opcode;
3991 
3992             // If the argument is constant, fold it.
3993             if (argtype.constValue() != null) {
3994                 Type ctype = cfolder.fold1(opc, argtype);
3995                 if (ctype != null) {
3996                     owntype = cfolder.coerce(ctype, owntype);
3997                 }
3998             }
3999         }
4000         result = check(tree, owntype, KindSelector.VAL, resultInfo);
4001         matchBindings = matchBindingsComputer.unary(tree, matchBindings);
4002     }
4003 
4004     public void visitBinary(JCBinary tree) {
4005         // Attribute arguments.
4006         Type left = chk.checkNonVoid(tree.lhs.pos(), attribExpr(tree.lhs, env));
4007         // x && y
4008         // include x's bindings when true in y
4009 
4010         // x || y
4011         // include x's bindings when false in y
4012 
4013         MatchBindings lhsBindings = matchBindings;
4014         List<BindingSymbol> propagatedBindings;
4015         switch (tree.getTag()) {
4016             case AND:
4017                 propagatedBindings = lhsBindings.bindingsWhenTrue;
4018                 break;
4019             case OR:
4020                 propagatedBindings = lhsBindings.bindingsWhenFalse;
4021                 break;
4022             default:
4023                 propagatedBindings = List.nil();
4024                 break;
4025         }
4026         Env<AttrContext> rhsEnv = bindingEnv(env, propagatedBindings);
4027         Type right;
4028         try {
4029             right = chk.checkNonVoid(tree.rhs.pos(), attribExpr(tree.rhs, rhsEnv));
4030         } finally {
4031             rhsEnv.info.scope.leave();
4032         }
4033 
4034         matchBindings = matchBindingsComputer.binary(tree, lhsBindings, matchBindings);
4035 
4036         // Find operator.
4037         OperatorSymbol operator = tree.operator = operators.resolveBinary(tree, tree.getTag(), left, right);
4038         Type owntype = types.createErrorType(tree.type);
4039         if (operator != operators.noOpSymbol &&
4040                 !left.isErroneous() &&
4041                 !right.isErroneous()) {
4042             owntype = operator.type.getReturnType();
4043             int opc = operator.opcode;
4044             // If both arguments are constants, fold them.
4045             if (left.constValue() != null && right.constValue() != null) {
4046                 Type ctype = cfolder.fold2(opc, left, right);
4047                 if (ctype != null) {
4048                     owntype = cfolder.coerce(ctype, owntype);
4049                 }
4050             }
4051 
4052             // Check that argument types of a reference ==, != are
4053             // castable to each other, (JLS 15.21).  Note: unboxing
4054             // comparisons will not have an acmp* opc at this point.
4055             if ((opc == ByteCodes.if_acmpeq || opc == ByteCodes.if_acmpne)) {
4056                 if (!types.isCastable(left, right, new Warner(tree.pos()))) {
4057                     log.error(tree.pos(), Errors.IncomparableTypes(left, right));
4058                 }
4059             }
4060 
4061             chk.checkDivZero(tree.rhs.pos(), operator, right);
4062         }
4063         result = check(tree, owntype, KindSelector.VAL, resultInfo);
4064     }
4065 
4066     public void visitTypeCast(final JCTypeCast tree) {
4067         Type clazztype = attribType(tree.clazz, env);
4068         chk.validate(tree.clazz, env, false);
4069         //a fresh environment is required for 292 inference to work properly ---
4070         //see Infer.instantiatePolymorphicSignatureInstance()
4071         Env<AttrContext> localEnv = env.dup(tree);
4072         //should we propagate the target type?
4073         final ResultInfo castInfo;
4074         JCExpression expr = TreeInfo.skipParens(tree.expr);
4075         boolean isPoly = (expr.hasTag(LAMBDA) || expr.hasTag(REFERENCE));
4076         if (isPoly) {
4077             //expression is a poly - we need to propagate target type info
4078             castInfo = new ResultInfo(KindSelector.VAL, clazztype,
4079                                       new Check.NestedCheckContext(resultInfo.checkContext) {
4080                 @Override
4081                 public boolean compatible(Type found, Type req, Warner warn) {
4082                     return types.isCastable(found, req, warn);
4083                 }
4084             });
4085         } else {
4086             //standalone cast - target-type info is not propagated
4087             castInfo = unknownExprInfo;
4088         }
4089         Type exprtype = attribTree(tree.expr, localEnv, castInfo);
4090         Type owntype = isPoly ? clazztype : chk.checkCastable(tree.expr.pos(), exprtype, clazztype);
4091         if (exprtype.constValue() != null)
4092             owntype = cfolder.coerce(exprtype, owntype);
4093         result = check(tree, capture(owntype), KindSelector.VAL, resultInfo);
4094         if (!isPoly)
4095             chk.checkRedundantCast(localEnv, tree);
4096     }
4097 
4098     public void visitTypeTest(JCInstanceOf tree) {
4099         Type exprtype = chk.checkNullOrRefType(
4100                 tree.expr.pos(), attribExpr(tree.expr, env));
4101         Type clazztype;
4102         JCTree typeTree;
4103         if (tree.pattern.getTag() == BINDINGPATTERN ||
4104             tree.pattern.getTag() == PARENTHESIZEDPATTERN ||
4105             tree.pattern.getTag() == RECORDPATTERN) {
4106             attribExpr(tree.pattern, env, exprtype);
4107             clazztype = tree.pattern.type;
4108             if (types.isSubtype(exprtype, clazztype) &&
4109                 !exprtype.isErroneous() && !clazztype.isErroneous() &&
4110                 tree.pattern.getTag() != RECORDPATTERN) {
4111                 if (!allowUnconditionalPatternsInstanceOf) {
4112                     log.error(tree.pos(), Errors.InstanceofPatternNoSubtype(exprtype, clazztype));
4113                 } else if (preview.isPreview(Feature.UNCONDITIONAL_PATTERN_IN_INSTANCEOF)) {
4114                     preview.warnPreview(tree.pattern.pos(), Feature.UNCONDITIONAL_PATTERN_IN_INSTANCEOF);
4115                 }
4116             }
4117             typeTree = TreeInfo.primaryPatternTypeTree((JCPattern) tree.pattern);
4118         } else {
4119             clazztype = attribType(tree.pattern, env);
4120             typeTree = tree.pattern;
4121             chk.validate(typeTree, env, false);
4122         }
4123         if (!clazztype.hasTag(TYPEVAR)) {
4124             clazztype = chk.checkClassOrArrayType(typeTree.pos(), clazztype);
4125         }
4126         if (!clazztype.isErroneous() && !types.isReifiable(clazztype)) {
4127             boolean valid = false;
4128             if (allowReifiableTypesInInstanceof) {
4129                 valid = checkCastablePattern(tree.expr.pos(), exprtype, clazztype);
4130             } else {
4131                 log.error(DiagnosticFlag.SOURCE_LEVEL, tree.pos(),
4132                           Feature.REIFIABLE_TYPES_INSTANCEOF.error(this.sourceName));
4133                 allowReifiableTypesInInstanceof = true;
4134             }
4135             if (!valid) {
4136                 clazztype = types.createErrorType(clazztype);
4137             }
4138         }
4139         chk.checkCastable(tree.expr.pos(), exprtype, clazztype);
4140         result = check(tree, syms.booleanType, KindSelector.VAL, resultInfo);
4141     }
4142 
4143     private boolean checkCastablePattern(DiagnosticPosition pos,
4144                                          Type exprType,
4145                                          Type pattType) {
4146         Warner warner = new Warner();
4147         // if any type is erroneous, the problem is reported elsewhere
4148         if (exprType.isErroneous() || pattType.isErroneous()) {
4149             return false;
4150         }
4151         if (!types.isCastable(exprType, pattType, warner)) {
4152             chk.basicHandler.report(pos,
4153                     diags.fragment(Fragments.InconvertibleTypes(exprType, pattType)));
4154             return false;
4155         } else if ((exprType.isPrimitive() || pattType.isPrimitive()) &&
4156                    (!exprType.isPrimitive() ||
4157                     !pattType.isPrimitive() ||
4158                     !types.isSameType(exprType, pattType))) {
4159             chk.basicHandler.report(pos,
4160                     diags.fragment(Fragments.NotApplicableTypes(exprType, pattType)));
4161             return false;
4162         } else if (warner.hasLint(LintCategory.UNCHECKED)) {
4163             log.error(pos,
4164                     Errors.InstanceofReifiableNotSafe(exprType, pattType));
4165             return false;
4166         } else {
4167             return true;
4168         }
4169     }
4170 
4171     public void visitBindingPattern(JCBindingPattern tree) {
4172         Type type;
4173         if (tree.var.vartype != null) {
4174             type = attribType(tree.var.vartype, env);
4175         } else {
4176             type = resultInfo.pt;
4177         }
4178         tree.type = tree.var.type = type;
4179         BindingSymbol v = new BindingSymbol(tree.var.mods.flags, tree.var.name, type, env.info.scope.owner);
4180         v.pos = tree.pos;
4181         tree.var.sym = v;
4182         if (chk.checkUnique(tree.var.pos(), v, env.info.scope)) {
4183             chk.checkTransparentVar(tree.var.pos(), v, env.info.scope);
4184         }
4185         if (tree.var.vartype != null) {
4186             annotate.annotateLater(tree.var.mods.annotations, env, v, tree.pos());
4187             annotate.queueScanTreeAndTypeAnnotate(tree.var.vartype, env, v, tree.var.pos());
4188             annotate.flush();
4189         }
4190         chk.validate(tree.var.vartype, env, true);
4191         result = tree.type;
4192         matchBindings = new MatchBindings(List.of(v), List.nil());
4193     }
4194 
4195     @Override
4196     public void visitRecordPattern(JCRecordPattern tree) {
4197         Type type = attribType(tree.deconstructor, env);
4198         if (type.isRaw() && type.tsym.getTypeParameters().nonEmpty()) {
4199             Type inferred = infer.instantiatePatternType(resultInfo.pt, type.tsym);
4200             if (inferred == null) {
4201                 log.error(tree.pos(), Errors.PatternTypeCannotInfer);
4202             } else {
4203                 type = inferred;
4204             }
4205         }
4206         tree.type = tree.deconstructor.type = type;
4207         Type site = types.capture(tree.type);
4208         List<Type> expectedRecordTypes;
4209         if (site.tsym.kind == Kind.TYP && ((ClassSymbol) site.tsym).isRecord()) {
4210             ClassSymbol record = (ClassSymbol) site.tsym;
4211             expectedRecordTypes = record.getRecordComponents()
4212                                         .stream()
4213                                         .map(rc -> types.memberType(site, rc))
4214                                         .map(t -> types.upward(t, types.captures(t)).baseType())
4215                                         .collect(List.collector());
4216             tree.record = record;
4217         } else {
4218             log.error(tree.pos(), Errors.DeconstructionPatternOnlyRecords(site.tsym));
4219             expectedRecordTypes = Stream.generate(() -> types.createErrorType(tree.type))
4220                                 .limit(tree.nested.size())
4221                                 .collect(List.collector());
4222             tree.record = syms.errSymbol;
4223         }
4224         ListBuffer<BindingSymbol> outBindings = new ListBuffer<>();
4225         List<Type> recordTypes = expectedRecordTypes;
4226         List<JCPattern> nestedPatterns = tree.nested;
4227         Env<AttrContext> localEnv = env.dup(tree, env.info.dup(env.info.scope.dup()));
4228         try {
4229             while (recordTypes.nonEmpty() && nestedPatterns.nonEmpty()) {
4230                 attribExpr(nestedPatterns.head, localEnv, recordTypes.head);
4231                 checkCastablePattern(nestedPatterns.head.pos(), recordTypes.head, nestedPatterns.head.type);
4232                 outBindings.addAll(matchBindings.bindingsWhenTrue);
4233                 matchBindings.bindingsWhenTrue.forEach(localEnv.info.scope::enter);
4234                 nestedPatterns = nestedPatterns.tail;
4235                 recordTypes = recordTypes.tail;
4236             }
4237             if (recordTypes.nonEmpty() || nestedPatterns.nonEmpty()) {
4238                 while (nestedPatterns.nonEmpty()) {
4239                     attribExpr(nestedPatterns.head, localEnv, Type.noType);
4240                     nestedPatterns = nestedPatterns.tail;
4241                 }
4242                 List<Type> nestedTypes =
4243                         tree.nested.stream().map(p -> p.type).collect(List.collector());
4244                 log.error(tree.pos(),
4245                           Errors.IncorrectNumberOfNestedPatterns(expectedRecordTypes,
4246                                                                  nestedTypes));
4247             }
4248         } finally {
4249             localEnv.info.scope.leave();
4250         }
4251         chk.validate(tree.deconstructor, env, true);
4252         result = tree.type;
4253         matchBindings = new MatchBindings(outBindings.toList(), List.nil());
4254     }
4255 
4256     public void visitParenthesizedPattern(JCParenthesizedPattern tree) {
4257         attribExpr(tree.pattern, env);
4258         result = tree.type = tree.pattern.type;
4259     }
4260 
4261     public void visitIndexed(JCArrayAccess tree) {
4262         Type owntype = types.createErrorType(tree.type);
4263         Type atype = attribExpr(tree.indexed, env);
4264         attribExpr(tree.index, env, syms.intType);
4265         if (types.isArray(atype))
4266             owntype = types.elemtype(atype);
4267         else if (!atype.hasTag(ERROR))
4268             log.error(tree.pos(), Errors.ArrayReqButFound(atype));
4269         if (!pkind().contains(KindSelector.VAL))
4270             owntype = capture(owntype);
4271         result = check(tree, owntype, KindSelector.VAR, resultInfo);
4272     }
4273 
4274     public void visitIdent(JCIdent tree) {
4275         Symbol sym;
4276 
4277         // Find symbol
4278         if (pt().hasTag(METHOD) || pt().hasTag(FORALL)) {
4279             // If we are looking for a method, the prototype `pt' will be a
4280             // method type with the type of the call's arguments as parameters.
4281             env.info.pendingResolutionPhase = null;
4282             sym = rs.resolveMethod(tree.pos(), env, tree.name, pt().getParameterTypes(), pt().getTypeArguments());
4283         } else if (tree.sym != null && tree.sym.kind != VAR) {
4284             sym = tree.sym;
4285         } else {
4286             sym = rs.resolveIdent(tree.pos(), env, tree.name, pkind());
4287         }
4288         tree.sym = sym;
4289 
4290         // Also find the environment current for the class where
4291         // sym is defined (`symEnv').
4292         Env<AttrContext> symEnv = env;
4293         if (env.enclClass.sym.owner.kind != PCK && // we are in an inner class
4294             sym.kind.matches(KindSelector.VAL_MTH) &&
4295             sym.owner.kind == TYP &&
4296             tree.name != names._this && tree.name != names._super) {
4297 
4298             // Find environment in which identifier is defined.
4299             while (symEnv.outer != null &&
4300                    !sym.isMemberOf(symEnv.enclClass.sym, types)) {
4301                 symEnv = symEnv.outer;
4302             }
4303         }
4304 
4305         // If symbol is a variable, ...
4306         if (sym.kind == VAR) {
4307             VarSymbol v = (VarSymbol)sym;
4308 
4309             // ..., evaluate its initializer, if it has one, and check for
4310             // illegal forward reference.
4311             checkInit(tree, env, v, false);
4312 
4313             // If we are expecting a variable (as opposed to a value), check
4314             // that the variable is assignable in the current environment.
4315             if (KindSelector.ASG.subset(pkind()))
4316                 checkAssignable(tree.pos(), v, null, env);
4317         }
4318 
4319         // In a constructor body,
4320         // if symbol is a field or instance method, check that it is
4321         // not accessed before the supertype constructor is called.
4322         if (symEnv.info.isSelfCall &&
4323             sym.kind.matches(KindSelector.VAL_MTH) &&
4324             sym.owner.kind == TYP &&
4325             (sym.flags() & STATIC) == 0) {
4326             chk.earlyRefError(tree.pos(), sym.kind == VAR ?
4327                                           sym : thisSym(tree.pos(), env));
4328         }
4329         Env<AttrContext> env1 = env;
4330         if (sym.kind != ERR && sym.kind != TYP &&
4331             sym.owner != null && sym.owner != env1.enclClass.sym) {
4332             // If the found symbol is inaccessible, then it is
4333             // accessed through an enclosing instance.  Locate this
4334             // enclosing instance:
4335             while (env1.outer != null && !rs.isAccessible(env, env1.enclClass.sym.type, sym))
4336                 env1 = env1.outer;
4337         }
4338 
4339         if (env.info.isSerializable) {
4340             chk.checkAccessFromSerializableElement(tree, env.info.isSerializableLambda);
4341         }
4342 
4343         result = checkId(tree, env1.enclClass.sym.type, sym, env, resultInfo);
4344     }
4345 
4346     public void visitSelect(JCFieldAccess tree) {
4347         // Determine the expected kind of the qualifier expression.
4348         KindSelector skind = KindSelector.NIL;
4349         if (tree.name == names._this || tree.name == names._super ||
4350                 tree.name == names._class)
4351         {
4352             skind = KindSelector.TYP;
4353         } else {
4354             if (pkind().contains(KindSelector.PCK))
4355                 skind = KindSelector.of(skind, KindSelector.PCK);
4356             if (pkind().contains(KindSelector.TYP))
4357                 skind = KindSelector.of(skind, KindSelector.TYP, KindSelector.PCK);
4358             if (pkind().contains(KindSelector.VAL_MTH))
4359                 skind = KindSelector.of(skind, KindSelector.VAL, KindSelector.TYP);
4360         }
4361 
4362         // Attribute the qualifier expression, and determine its symbol (if any).
4363         Type site = attribTree(tree.selected, env, new ResultInfo(skind, Type.noType));
4364         if (!pkind().contains(KindSelector.TYP_PCK))
4365             site = capture(site); // Capture field access
4366 
4367         // don't allow T.class T[].class, etc
4368         if (skind == KindSelector.TYP) {
4369             Type elt = site;
4370             while (elt.hasTag(ARRAY))
4371                 elt = ((ArrayType)elt).elemtype;
4372             if (elt.hasTag(TYPEVAR)) {
4373                 log.error(tree.pos(), Errors.TypeVarCantBeDeref);
4374                 result = tree.type = types.createErrorType(tree.name, site.tsym, site);
4375                 tree.sym = tree.type.tsym;
4376                 return ;
4377             }
4378         }
4379 
4380         // If qualifier symbol is a type or `super', assert `selectSuper'
4381         // for the selection. This is relevant for determining whether
4382         // protected symbols are accessible.
4383         Symbol sitesym = TreeInfo.symbol(tree.selected);
4384         boolean selectSuperPrev = env.info.selectSuper;
4385         env.info.selectSuper =
4386             sitesym != null &&
4387             sitesym.name == names._super;
4388 
4389         // Determine the symbol represented by the selection.
4390         env.info.pendingResolutionPhase = null;
4391         Symbol sym = selectSym(tree, sitesym, site, env, resultInfo);
4392         if (sym.kind == VAR && sym.name != names._super && env.info.defaultSuperCallSite != null) {
4393             log.error(tree.selected.pos(), Errors.NotEnclClass(site.tsym));
4394             sym = syms.errSymbol;
4395         }
4396         if (sym.exists() && !isType(sym) && pkind().contains(KindSelector.TYP_PCK)) {
4397             site = capture(site);
4398             sym = selectSym(tree, sitesym, site, env, resultInfo);
4399         }
4400         boolean varArgs = env.info.lastResolveVarargs();
4401         tree.sym = sym;
4402 
4403         if (site.hasTag(TYPEVAR) && !isType(sym) && sym.kind != ERR) {
4404             site = types.skipTypeVars(site, true);
4405         }
4406 
4407         // If that symbol is a variable, ...
4408         if (sym.kind == VAR) {
4409             VarSymbol v = (VarSymbol)sym;
4410 
4411             // ..., evaluate its initializer, if it has one, and check for
4412             // illegal forward reference.
4413             checkInit(tree, env, v, true);
4414 
4415             // If we are expecting a variable (as opposed to a value), check
4416             // that the variable is assignable in the current environment.
4417             if (KindSelector.ASG.subset(pkind()))
4418                 checkAssignable(tree.pos(), v, tree.selected, env);
4419         }
4420 
4421         if (sitesym != null &&
4422                 sitesym.kind == VAR &&
4423                 ((VarSymbol)sitesym).isResourceVariable() &&
4424                 sym.kind == MTH &&
4425                 sym.name.equals(names.close) &&
4426                 sym.overrides(syms.autoCloseableClose, sitesym.type.tsym, types, true) &&
4427                 env.info.lint.isEnabled(LintCategory.TRY)) {
4428             log.warning(LintCategory.TRY, tree, Warnings.TryExplicitCloseCall);
4429         }
4430 
4431         // Disallow selecting a type from an expression
4432         if (isType(sym) && (sitesym == null || !sitesym.kind.matches(KindSelector.TYP_PCK))) {
4433             tree.type = check(tree.selected, pt(),
4434                               sitesym == null ?
4435                                       KindSelector.VAL : sitesym.kind.toSelector(),
4436                               new ResultInfo(KindSelector.TYP_PCK, pt()));
4437         }
4438 
4439         if (isType(sitesym)) {
4440             if (sym.name == names._this || sym.name == names._super) {
4441                 // If `C' is the currently compiled class, check that
4442                 // `C.this' does not appear in an explicit call to a constructor
4443                 // also make sure that `super` is not used in constructor invocations
4444                 if (env.info.isSelfCall &&
4445                         ((sym.name == names._this &&
4446                         site.tsym == env.enclClass.sym) ||
4447                         sym.name == names._super && env.info.constructorArgs &&
4448                         (sitesym.isInterface() || site.tsym == env.enclClass.sym))) {
4449                     chk.earlyRefError(tree.pos(), sym);
4450                 }
4451             } else {
4452                 // Check if type-qualified fields or methods are static (JLS)
4453                 if ((sym.flags() & STATIC) == 0 &&
4454                     sym.name != names._super &&
4455                     (sym.kind == VAR || sym.kind == MTH)) {
4456                     rs.accessBase(rs.new StaticError(sym),
4457                               tree.pos(), site, sym.name, true);
4458                 }
4459             }
4460         } else if (sym.kind != ERR &&
4461                    (sym.flags() & STATIC) != 0 &&
4462                    sym.name != names._class) {
4463             // If the qualified item is not a type and the selected item is static, report
4464             // a warning. Make allowance for the class of an array type e.g. Object[].class)
4465             if (!sym.owner.isAnonymous()) {
4466                 chk.warnStatic(tree, Warnings.StaticNotQualifiedByType(sym.kind.kindName(), sym.owner));
4467             } else {
4468                 chk.warnStatic(tree, Warnings.StaticNotQualifiedByType2(sym.kind.kindName()));
4469             }
4470         }
4471 
4472         // If we are selecting an instance member via a `super', ...
4473         if (env.info.selectSuper && (sym.flags() & STATIC) == 0) {
4474 
4475             // Check that super-qualified symbols are not abstract (JLS)
4476             rs.checkNonAbstract(tree.pos(), sym);
4477 
4478             if (site.isRaw()) {
4479                 // Determine argument types for site.
4480                 Type site1 = types.asSuper(env.enclClass.sym.type, site.tsym);
4481                 if (site1 != null) site = site1;
4482             }
4483         }
4484 
4485         if (env.info.isSerializable) {
4486             chk.checkAccessFromSerializableElement(tree, env.info.isSerializableLambda);
4487         }
4488 
4489         env.info.selectSuper = selectSuperPrev;
4490         result = checkId(tree, site, sym, env, resultInfo);
4491     }
4492     //where
4493         /** Determine symbol referenced by a Select expression,
4494          *
4495          *  @param tree   The select tree.
4496          *  @param site   The type of the selected expression,
4497          *  @param env    The current environment.
4498          *  @param resultInfo The current result.
4499          */
4500         private Symbol selectSym(JCFieldAccess tree,
4501                                  Symbol location,
4502                                  Type site,
4503                                  Env<AttrContext> env,
4504                                  ResultInfo resultInfo) {
4505             DiagnosticPosition pos = tree.pos();
4506             Name name = tree.name;
4507             switch (site.getTag()) {
4508             case PACKAGE:
4509                 return rs.accessBase(
4510                     rs.findIdentInPackage(pos, env, site.tsym, name, resultInfo.pkind),
4511                     pos, location, site, name, true);
4512             case ARRAY:
4513             case CLASS:
4514                 if (resultInfo.pt.hasTag(METHOD) || resultInfo.pt.hasTag(FORALL)) {
4515                     return rs.resolveQualifiedMethod(
4516                         pos, env, location, site, name, resultInfo.pt.getParameterTypes(), resultInfo.pt.getTypeArguments());
4517                 } else if (name == names._this || name == names._super) {
4518                     return rs.resolveSelf(pos, env, site.tsym, name);
4519                 } else if (name == names._class) {
4520                     // In this case, we have already made sure in
4521                     // visitSelect that qualifier expression is a type.
4522                     return syms.getClassField(site, types);
4523                 } else {
4524                     // We are seeing a plain identifier as selector.
4525                     Symbol sym = rs.findIdentInType(pos, env, site, name, resultInfo.pkind);
4526                         sym = rs.accessBase(sym, pos, location, site, name, true);
4527                     return sym;
4528                 }
4529             case WILDCARD:
4530                 throw new AssertionError(tree);
4531             case TYPEVAR:
4532                 // Normally, site.getUpperBound() shouldn't be null.
4533                 // It should only happen during memberEnter/attribBase
4534                 // when determining the supertype which *must* be
4535                 // done before attributing the type variables.  In
4536                 // other words, we are seeing this illegal program:
4537                 // class B<T> extends A<T.foo> {}
4538                 Symbol sym = (site.getUpperBound() != null)
4539                     ? selectSym(tree, location, capture(site.getUpperBound()), env, resultInfo)
4540                     : null;
4541                 if (sym == null) {
4542                     log.error(pos, Errors.TypeVarCantBeDeref);
4543                     return syms.errSymbol;
4544                 } else {
4545                     Symbol sym2 = (sym.flags() & Flags.PRIVATE) != 0 ?
4546                         rs.new AccessError(env, site, sym) :
4547                                 sym;
4548                     rs.accessBase(sym2, pos, location, site, name, true);
4549                     return sym;
4550                 }
4551             case ERROR:
4552                 // preserve identifier names through errors
4553                 return types.createErrorType(name, site.tsym, site).tsym;
4554             default:
4555                 // The qualifier expression is of a primitive type -- only
4556                 // .class is allowed for these.
4557                 if (name == names._class) {
4558                     // In this case, we have already made sure in Select that
4559                     // qualifier expression is a type.
4560                     return syms.getClassField(site, types);
4561                 } else {
4562                     log.error(pos, Errors.CantDeref(site));
4563                     return syms.errSymbol;
4564                 }
4565             }
4566         }
4567 
4568         /** Determine type of identifier or select expression and check that
4569          *  (1) the referenced symbol is not deprecated
4570          *  (2) the symbol's type is safe (@see checkSafe)
4571          *  (3) if symbol is a variable, check that its type and kind are
4572          *      compatible with the prototype and protokind.
4573          *  (4) if symbol is an instance field of a raw type,
4574          *      which is being assigned to, issue an unchecked warning if its
4575          *      type changes under erasure.
4576          *  (5) if symbol is an instance method of a raw type, issue an
4577          *      unchecked warning if its argument types change under erasure.
4578          *  If checks succeed:
4579          *    If symbol is a constant, return its constant type
4580          *    else if symbol is a method, return its result type
4581          *    otherwise return its type.
4582          *  Otherwise return errType.
4583          *
4584          *  @param tree       The syntax tree representing the identifier
4585          *  @param site       If this is a select, the type of the selected
4586          *                    expression, otherwise the type of the current class.
4587          *  @param sym        The symbol representing the identifier.
4588          *  @param env        The current environment.
4589          *  @param resultInfo    The expected result
4590          */
4591         Type checkId(JCTree tree,
4592                      Type site,
4593                      Symbol sym,
4594                      Env<AttrContext> env,
4595                      ResultInfo resultInfo) {
4596             return (resultInfo.pt.hasTag(FORALL) || resultInfo.pt.hasTag(METHOD)) ?
4597                     checkMethodIdInternal(tree, site, sym, env, resultInfo) :
4598                     checkIdInternal(tree, site, sym, resultInfo.pt, env, resultInfo);
4599         }
4600 
4601         Type checkMethodIdInternal(JCTree tree,
4602                      Type site,
4603                      Symbol sym,
4604                      Env<AttrContext> env,
4605                      ResultInfo resultInfo) {
4606             if (resultInfo.pkind.contains(KindSelector.POLY)) {
4607                 return attrRecover.recoverMethodInvocation(tree, site, sym, env, resultInfo);
4608             } else {
4609                 return checkIdInternal(tree, site, sym, resultInfo.pt, env, resultInfo);
4610             }
4611         }
4612 
4613         Type checkIdInternal(JCTree tree,
4614                      Type site,
4615                      Symbol sym,
4616                      Type pt,
4617                      Env<AttrContext> env,
4618                      ResultInfo resultInfo) {
4619             if (pt.isErroneous()) {
4620                 return types.createErrorType(site);
4621             }
4622             Type owntype; // The computed type of this identifier occurrence.
4623             switch (sym.kind) {
4624             case TYP:
4625                 // For types, the computed type equals the symbol's type,
4626                 // except for two situations:
4627                 owntype = sym.type;
4628                 if (owntype.hasTag(CLASS)) {
4629                     chk.checkForBadAuxiliaryClassAccess(tree.pos(), env, (ClassSymbol)sym);
4630                     Type ownOuter = owntype.getEnclosingType();
4631 
4632                     // (a) If the symbol's type is parameterized, erase it
4633                     // because no type parameters were given.
4634                     // We recover generic outer type later in visitTypeApply.
4635                     if (owntype.tsym.type.getTypeArguments().nonEmpty()) {
4636                         owntype = types.erasure(owntype);
4637                     }
4638 
4639                     // (b) If the symbol's type is an inner class, then
4640                     // we have to interpret its outer type as a superclass
4641                     // of the site type. Example:
4642                     //
4643                     // class Tree<A> { class Visitor { ... } }
4644                     // class PointTree extends Tree<Point> { ... }
4645                     // ...PointTree.Visitor...
4646                     //
4647                     // Then the type of the last expression above is
4648                     // Tree<Point>.Visitor.
4649                     else if (ownOuter.hasTag(CLASS) && site != ownOuter) {
4650                         Type normOuter = site;
4651                         if (normOuter.hasTag(CLASS)) {
4652                             normOuter = types.asEnclosingSuper(site, ownOuter.tsym);
4653                         }
4654                         if (normOuter == null) // perhaps from an import
4655                             normOuter = types.erasure(ownOuter);
4656                         if (normOuter != ownOuter)
4657                             owntype = new ClassType(
4658                                 normOuter, List.nil(), owntype.tsym,
4659                                 owntype.getMetadata());
4660                     }
4661                 }
4662                 break;
4663             case VAR:
4664                 VarSymbol v = (VarSymbol)sym;
4665 
4666                 if (env.info.enclVar != null
4667                         && v.type.hasTag(NONE)) {
4668                     //self reference to implicitly typed variable declaration
4669                     log.error(TreeInfo.positionFor(v, env.enclClass), Errors.CantInferLocalVarType(v.name, Fragments.LocalSelfRef));
4670                     return tree.type = v.type = types.createErrorType(v.type);
4671                 }
4672 
4673                 // Test (4): if symbol is an instance field of a raw type,
4674                 // which is being assigned to, issue an unchecked warning if
4675                 // its type changes under erasure.
4676                 if (KindSelector.ASG.subset(pkind()) &&
4677                     v.owner.kind == TYP &&
4678                     (v.flags() & STATIC) == 0 &&
4679                     (site.hasTag(CLASS) || site.hasTag(TYPEVAR))) {
4680                     Type s = types.asOuterSuper(site, v.owner);
4681                     if (s != null &&
4682                         s.isRaw() &&
4683                         !types.isSameType(v.type, v.erasure(types))) {
4684                         chk.warnUnchecked(tree.pos(), Warnings.UncheckedAssignToVar(v, s));
4685                     }
4686                 }
4687                 // The computed type of a variable is the type of the
4688                 // variable symbol, taken as a member of the site type.
4689                 owntype = (sym.owner.kind == TYP &&
4690                            sym.name != names._this && sym.name != names._super)
4691                     ? types.memberType(site, sym)
4692                     : sym.type;
4693 
4694                 // If the variable is a constant, record constant value in
4695                 // computed type.
4696                 if (v.getConstValue() != null && isStaticReference(tree))
4697                     owntype = owntype.constType(v.getConstValue());
4698 
4699                 if (resultInfo.pkind == KindSelector.VAL) {
4700                     owntype = capture(owntype); // capture "names as expressions"
4701                 }
4702                 break;
4703             case MTH: {
4704                 owntype = checkMethod(site, sym,
4705                         new ResultInfo(resultInfo.pkind, resultInfo.pt.getReturnType(), resultInfo.checkContext, resultInfo.checkMode),
4706                         env, TreeInfo.args(env.tree), resultInfo.pt.getParameterTypes(),
4707                         resultInfo.pt.getTypeArguments());
4708                 break;
4709             }
4710             case PCK: case ERR:
4711                 owntype = sym.type;
4712                 break;
4713             default:
4714                 throw new AssertionError("unexpected kind: " + sym.kind +
4715                                          " in tree " + tree);
4716             }
4717 
4718             // Emit a `deprecation' warning if symbol is deprecated.
4719             // (for constructors (but not for constructor references), the error
4720             // was given when the constructor was resolved)
4721 
4722             if (sym.name != names.init || tree.hasTag(REFERENCE)) {
4723                 chk.checkDeprecated(tree.pos(), env.info.scope.owner, sym);
4724                 chk.checkSunAPI(tree.pos(), sym);
4725                 chk.checkProfile(tree.pos(), sym);
4726                 chk.checkPreview(tree.pos(), env.info.scope.owner, sym);
4727             }
4728 
4729             // If symbol is a variable, check that its type and
4730             // kind are compatible with the prototype and protokind.
4731             return check(tree, owntype, sym.kind.toSelector(), resultInfo);
4732         }
4733 
4734         /** Check that variable is initialized and evaluate the variable's
4735          *  initializer, if not yet done. Also check that variable is not
4736          *  referenced before it is defined.
4737          *  @param tree    The tree making up the variable reference.
4738          *  @param env     The current environment.
4739          *  @param v       The variable's symbol.
4740          */
4741         private void checkInit(JCTree tree,
4742                                Env<AttrContext> env,
4743                                VarSymbol v,
4744                                boolean onlyWarning) {
4745             // A forward reference is diagnosed if the declaration position
4746             // of the variable is greater than the current tree position
4747             // and the tree and variable definition occur in the same class
4748             // definition.  Note that writes don't count as references.
4749             // This check applies only to class and instance
4750             // variables.  Local variables follow different scope rules,
4751             // and are subject to definite assignment checking.
4752             Env<AttrContext> initEnv = enclosingInitEnv(env);
4753             if (initEnv != null &&
4754                 (initEnv.info.enclVar == v || v.pos > tree.pos) &&
4755                 v.owner.kind == TYP &&
4756                 v.owner == env.info.scope.owner.enclClass() &&
4757                 ((v.flags() & STATIC) != 0) == Resolve.isStatic(env) &&
4758                 (!env.tree.hasTag(ASSIGN) ||
4759                  TreeInfo.skipParens(((JCAssign) env.tree).lhs) != tree)) {
4760                 if (!onlyWarning || isStaticEnumField(v)) {
4761                     Error errkey = (initEnv.info.enclVar == v) ?
4762                                 Errors.IllegalSelfRef : Errors.IllegalForwardRef;
4763                     log.error(tree.pos(), errkey);
4764                 } else if (useBeforeDeclarationWarning) {
4765                     Warning warnkey = (initEnv.info.enclVar == v) ?
4766                                 Warnings.SelfRef(v) : Warnings.ForwardRef(v);
4767                     log.warning(tree.pos(), warnkey);
4768                 }
4769             }
4770 
4771             v.getConstValue(); // ensure initializer is evaluated
4772 
4773             checkEnumInitializer(tree, env, v);
4774         }
4775 
4776         /**
4777          * Returns the enclosing init environment associated with this env (if any). An init env
4778          * can be either a field declaration env or a static/instance initializer env.
4779          */
4780         Env<AttrContext> enclosingInitEnv(Env<AttrContext> env) {
4781             while (true) {
4782                 switch (env.tree.getTag()) {
4783                     case VARDEF:
4784                         JCVariableDecl vdecl = (JCVariableDecl)env.tree;
4785                         if (vdecl.sym.owner.kind == TYP) {
4786                             //field
4787                             return env;
4788                         }
4789                         break;
4790                     case BLOCK:
4791                         if (env.next.tree.hasTag(CLASSDEF)) {
4792                             //instance/static initializer
4793                             return env;
4794                         }
4795                         break;
4796                     case METHODDEF:
4797                     case CLASSDEF:
4798                     case TOPLEVEL:
4799                         return null;
4800                 }
4801                 Assert.checkNonNull(env.next);
4802                 env = env.next;
4803             }
4804         }
4805 
4806         /**
4807          * Check for illegal references to static members of enum.  In
4808          * an enum type, constructors and initializers may not
4809          * reference its static members unless they are constant.
4810          *
4811          * @param tree    The tree making up the variable reference.
4812          * @param env     The current environment.
4813          * @param v       The variable's symbol.
4814          * @jls 8.9 Enum Types
4815          */
4816         private void checkEnumInitializer(JCTree tree, Env<AttrContext> env, VarSymbol v) {
4817             // JLS:
4818             //
4819             // "It is a compile-time error to reference a static field
4820             // of an enum type that is not a compile-time constant
4821             // (15.28) from constructors, instance initializer blocks,
4822             // or instance variable initializer expressions of that
4823             // type. It is a compile-time error for the constructors,
4824             // instance initializer blocks, or instance variable
4825             // initializer expressions of an enum constant e to refer
4826             // to itself or to an enum constant of the same type that
4827             // is declared to the right of e."
4828             if (isStaticEnumField(v)) {
4829                 ClassSymbol enclClass = env.info.scope.owner.enclClass();
4830 
4831                 if (enclClass == null || enclClass.owner == null)
4832                     return;
4833 
4834                 // See if the enclosing class is the enum (or a
4835                 // subclass thereof) declaring v.  If not, this
4836                 // reference is OK.
4837                 if (v.owner != enclClass && !types.isSubtype(enclClass.type, v.owner.type))
4838                     return;
4839 
4840                 // If the reference isn't from an initializer, then
4841                 // the reference is OK.
4842                 if (!Resolve.isInitializer(env))
4843                     return;
4844 
4845                 log.error(tree.pos(), Errors.IllegalEnumStaticRef);
4846             }
4847         }
4848 
4849         /** Is the given symbol a static, non-constant field of an Enum?
4850          *  Note: enum literals should not be regarded as such
4851          */
4852         private boolean isStaticEnumField(VarSymbol v) {
4853             return Flags.isEnum(v.owner) &&
4854                    Flags.isStatic(v) &&
4855                    !Flags.isConstant(v) &&
4856                    v.name != names._class;
4857         }
4858 
4859     /**
4860      * Check that method arguments conform to its instantiation.
4861      **/
4862     public Type checkMethod(Type site,
4863                             final Symbol sym,
4864                             ResultInfo resultInfo,
4865                             Env<AttrContext> env,
4866                             final List<JCExpression> argtrees,
4867                             List<Type> argtypes,
4868                             List<Type> typeargtypes) {
4869         // Test (5): if symbol is an instance method of a raw type, issue
4870         // an unchecked warning if its argument types change under erasure.
4871         if ((sym.flags() & STATIC) == 0 &&
4872             (site.hasTag(CLASS) || site.hasTag(TYPEVAR))) {
4873             Type s = types.asOuterSuper(site, sym.owner);
4874             if (s != null && s.isRaw() &&
4875                 !types.isSameTypes(sym.type.getParameterTypes(),
4876                                    sym.erasure(types).getParameterTypes())) {
4877                 chk.warnUnchecked(env.tree.pos(), Warnings.UncheckedCallMbrOfRawType(sym, s));
4878             }
4879         }
4880 
4881         if (env.info.defaultSuperCallSite != null) {
4882             for (Type sup : types.interfaces(env.enclClass.type).prepend(types.supertype((env.enclClass.type)))) {
4883                 if (!sup.tsym.isSubClass(sym.enclClass(), types) ||
4884                         types.isSameType(sup, env.info.defaultSuperCallSite)) continue;
4885                 List<MethodSymbol> icand_sup =
4886                         types.interfaceCandidates(sup, (MethodSymbol)sym);
4887                 if (icand_sup.nonEmpty() &&
4888                         icand_sup.head != sym &&
4889                         icand_sup.head.overrides(sym, icand_sup.head.enclClass(), types, true)) {
4890                     log.error(env.tree.pos(),
4891                               Errors.IllegalDefaultSuperCall(env.info.defaultSuperCallSite, Fragments.OverriddenDefault(sym, sup)));
4892                     break;
4893                 }
4894             }
4895             env.info.defaultSuperCallSite = null;
4896         }
4897 
4898         if (sym.isStatic() && site.isInterface() && env.tree.hasTag(APPLY)) {
4899             JCMethodInvocation app = (JCMethodInvocation)env.tree;
4900             if (app.meth.hasTag(SELECT) &&
4901                     !TreeInfo.isStaticSelector(((JCFieldAccess)app.meth).selected, names)) {
4902                 log.error(env.tree.pos(), Errors.IllegalStaticIntfMethCall(site));
4903             }
4904         }
4905 
4906         // Compute the identifier's instantiated type.
4907         // For methods, we need to compute the instance type by
4908         // Resolve.instantiate from the symbol's type as well as
4909         // any type arguments and value arguments.
4910         Warner noteWarner = new Warner();
4911         try {
4912             Type owntype = rs.checkMethod(
4913                     env,
4914                     site,
4915                     sym,
4916                     resultInfo,
4917                     argtypes,
4918                     typeargtypes,
4919                     noteWarner);
4920 
4921             DeferredAttr.DeferredTypeMap<Void> checkDeferredMap =
4922                 deferredAttr.new DeferredTypeMap<>(DeferredAttr.AttrMode.CHECK, sym, env.info.pendingResolutionPhase);
4923 
4924             argtypes = argtypes.map(checkDeferredMap);
4925 
4926             if (noteWarner.hasNonSilentLint(LintCategory.UNCHECKED)) {
4927                 chk.warnUnchecked(env.tree.pos(), Warnings.UncheckedMethInvocationApplied(kindName(sym),
4928                         sym.name,
4929                         rs.methodArguments(sym.type.getParameterTypes()),
4930                         rs.methodArguments(argtypes.map(checkDeferredMap)),
4931                         kindName(sym.location()),
4932                         sym.location()));
4933                 if (resultInfo.pt != Infer.anyPoly ||
4934                         !owntype.hasTag(METHOD) ||
4935                         !owntype.isPartial()) {
4936                     //if this is not a partially inferred method type, erase return type. Otherwise,
4937                     //erasure is carried out in PartiallyInferredMethodType.check().
4938                     owntype = new MethodType(owntype.getParameterTypes(),
4939                             types.erasure(owntype.getReturnType()),
4940                             types.erasure(owntype.getThrownTypes()),
4941                             syms.methodClass);
4942                 }
4943             }
4944 
4945             PolyKind pkind = (sym.type.hasTag(FORALL) &&
4946                  sym.type.getReturnType().containsAny(((ForAll)sym.type).tvars)) ?
4947                  PolyKind.POLY : PolyKind.STANDALONE;
4948             TreeInfo.setPolyKind(env.tree, pkind);
4949 
4950             return (resultInfo.pt == Infer.anyPoly) ?
4951                     owntype :
4952                     chk.checkMethod(owntype, sym, env, argtrees, argtypes, env.info.lastResolveVarargs(),
4953                             resultInfo.checkContext.inferenceContext());
4954         } catch (Infer.InferenceException ex) {
4955             //invalid target type - propagate exception outwards or report error
4956             //depending on the current check context
4957             resultInfo.checkContext.report(env.tree.pos(), ex.getDiagnostic());
4958             return types.createErrorType(site);
4959         } catch (Resolve.InapplicableMethodException ex) {
4960             final JCDiagnostic diag = ex.getDiagnostic();
4961             Resolve.InapplicableSymbolError errSym = rs.new InapplicableSymbolError(null) {
4962                 @Override
4963                 protected Pair<Symbol, JCDiagnostic> errCandidate() {
4964                     return new Pair<>(sym, diag);
4965                 }
4966             };
4967             List<Type> argtypes2 = argtypes.map(
4968                     rs.new ResolveDeferredRecoveryMap(AttrMode.CHECK, sym, env.info.pendingResolutionPhase));
4969             JCDiagnostic errDiag = errSym.getDiagnostic(JCDiagnostic.DiagnosticType.ERROR,
4970                     env.tree, sym, site, sym.name, argtypes2, typeargtypes);
4971             log.report(errDiag);
4972             return types.createErrorType(site);
4973         }
4974     }
4975 
4976     public void visitLiteral(JCLiteral tree) {
4977         result = check(tree, litType(tree.typetag).constType(tree.value),
4978                 KindSelector.VAL, resultInfo);
4979     }
4980     //where
4981     /** Return the type of a literal with given type tag.
4982      */
4983     Type litType(TypeTag tag) {
4984         return (tag == CLASS) ? syms.stringType : syms.typeOfTag[tag.ordinal()];
4985     }
4986 
4987     public void visitTypeIdent(JCPrimitiveTypeTree tree) {
4988         result = check(tree, syms.typeOfTag[tree.typetag.ordinal()], KindSelector.TYP, resultInfo);
4989     }
4990 
4991     public void visitTypeArray(JCArrayTypeTree tree) {
4992         Type etype = attribType(tree.elemtype, env);
4993         Type type = new ArrayType(etype, syms.arrayClass);
4994         result = check(tree, type, KindSelector.TYP, resultInfo);
4995     }
4996 
4997     /** Visitor method for parameterized types.
4998      *  Bound checking is left until later, since types are attributed
4999      *  before supertype structure is completely known
5000      */
5001     public void visitTypeApply(JCTypeApply tree) {
5002         Type owntype = types.createErrorType(tree.type);
5003 
5004         // Attribute functor part of application and make sure it's a class.
5005         Type clazztype = chk.checkClassType(tree.clazz.pos(), attribType(tree.clazz, env));
5006 
5007         // Attribute type parameters
5008         List<Type> actuals = attribTypes(tree.arguments, env);
5009 
5010         if (clazztype.hasTag(CLASS)) {
5011             List<Type> formals = clazztype.tsym.type.getTypeArguments();
5012             if (actuals.isEmpty()) //diamond
5013                 actuals = formals;
5014 
5015             if (actuals.length() == formals.length()) {
5016                 List<Type> a = actuals;
5017                 List<Type> f = formals;
5018                 while (a.nonEmpty()) {
5019                     a.head = a.head.withTypeVar(f.head);
5020                     a = a.tail;
5021                     f = f.tail;
5022                 }
5023                 // Compute the proper generic outer
5024                 Type clazzOuter = clazztype.getEnclosingType();
5025                 if (clazzOuter.hasTag(CLASS)) {
5026                     Type site;
5027                     JCExpression clazz = TreeInfo.typeIn(tree.clazz);
5028                     if (clazz.hasTag(IDENT)) {
5029                         site = env.enclClass.sym.type;
5030                     } else if (clazz.hasTag(SELECT)) {
5031                         site = ((JCFieldAccess) clazz).selected.type;
5032                     } else throw new AssertionError(""+tree);
5033                     if (clazzOuter.hasTag(CLASS) && site != clazzOuter) {
5034                         if (site.hasTag(CLASS))
5035                             site = types.asOuterSuper(site, clazzOuter.tsym);
5036                         if (site == null)
5037                             site = types.erasure(clazzOuter);
5038                         clazzOuter = site;
5039                     }
5040                 }
5041                 owntype = new ClassType(clazzOuter, actuals, clazztype.tsym,
5042                                         clazztype.getMetadata());
5043             } else {
5044                 if (formals.length() != 0) {
5045                     log.error(tree.pos(),
5046                               Errors.WrongNumberTypeArgs(Integer.toString(formals.length())));
5047                 } else {
5048                     log.error(tree.pos(), Errors.TypeDoesntTakeParams(clazztype.tsym));
5049                 }
5050                 owntype = types.createErrorType(tree.type);
5051             }
5052         }
5053         result = check(tree, owntype, KindSelector.TYP, resultInfo);
5054     }
5055 
5056     public void visitTypeUnion(JCTypeUnion tree) {
5057         ListBuffer<Type> multicatchTypes = new ListBuffer<>();
5058         ListBuffer<Type> all_multicatchTypes = null; // lazy, only if needed
5059         for (JCExpression typeTree : tree.alternatives) {
5060             Type ctype = attribType(typeTree, env);
5061             ctype = chk.checkType(typeTree.pos(),
5062                           chk.checkClassType(typeTree.pos(), ctype),
5063                           syms.throwableType);
5064             if (!ctype.isErroneous()) {
5065                 //check that alternatives of a union type are pairwise
5066                 //unrelated w.r.t. subtyping
5067                 if (chk.intersects(ctype,  multicatchTypes.toList())) {
5068                     for (Type t : multicatchTypes) {
5069                         boolean sub = types.isSubtype(ctype, t);
5070                         boolean sup = types.isSubtype(t, ctype);
5071                         if (sub || sup) {
5072                             //assume 'a' <: 'b'
5073                             Type a = sub ? ctype : t;
5074                             Type b = sub ? t : ctype;
5075                             log.error(typeTree.pos(), Errors.MulticatchTypesMustBeDisjoint(a, b));
5076                         }
5077                     }
5078                 }
5079                 multicatchTypes.append(ctype);
5080                 if (all_multicatchTypes != null)
5081                     all_multicatchTypes.append(ctype);
5082             } else {
5083                 if (all_multicatchTypes == null) {
5084                     all_multicatchTypes = new ListBuffer<>();
5085                     all_multicatchTypes.appendList(multicatchTypes);
5086                 }
5087                 all_multicatchTypes.append(ctype);
5088             }
5089         }
5090         Type t = check(tree, types.lub(multicatchTypes.toList()),
5091                 KindSelector.TYP, resultInfo.dup(CheckMode.NO_TREE_UPDATE));
5092         if (t.hasTag(CLASS)) {
5093             List<Type> alternatives =
5094                 ((all_multicatchTypes == null) ? multicatchTypes : all_multicatchTypes).toList();
5095             t = new UnionClassType((ClassType) t, alternatives);
5096         }
5097         tree.type = result = t;
5098     }
5099 
5100     public void visitTypeIntersection(JCTypeIntersection tree) {
5101         attribTypes(tree.bounds, env);
5102         tree.type = result = checkIntersection(tree, tree.bounds);
5103     }
5104 
5105     public void visitTypeParameter(JCTypeParameter tree) {
5106         TypeVar typeVar = (TypeVar) tree.type;
5107 
5108         if (tree.annotations != null && tree.annotations.nonEmpty()) {
5109             annotate.annotateTypeParameterSecondStage(tree, tree.annotations);
5110         }
5111 
5112         if (!typeVar.getUpperBound().isErroneous()) {
5113             //fixup type-parameter bound computed in 'attribTypeVariables'
5114             typeVar.setUpperBound(checkIntersection(tree, tree.bounds));
5115         }
5116     }
5117 
5118     Type checkIntersection(JCTree tree, List<JCExpression> bounds) {
5119         Set<Type> boundSet = new HashSet<>();
5120         if (bounds.nonEmpty()) {
5121             // accept class or interface or typevar as first bound.
5122             bounds.head.type = checkBase(bounds.head.type, bounds.head, env, false, false, false);
5123             boundSet.add(types.erasure(bounds.head.type));
5124             if (bounds.head.type.isErroneous()) {
5125                 return bounds.head.type;
5126             }
5127             else if (bounds.head.type.hasTag(TYPEVAR)) {
5128                 // if first bound was a typevar, do not accept further bounds.
5129                 if (bounds.tail.nonEmpty()) {
5130                     log.error(bounds.tail.head.pos(),
5131                               Errors.TypeVarMayNotBeFollowedByOtherBounds);
5132                     return bounds.head.type;
5133                 }
5134             } else {
5135                 // if first bound was a class or interface, accept only interfaces
5136                 // as further bounds.
5137                 for (JCExpression bound : bounds.tail) {
5138                     bound.type = checkBase(bound.type, bound, env, false, true, false);
5139                     if (bound.type.isErroneous()) {
5140                         bounds = List.of(bound);
5141                     }
5142                     else if (bound.type.hasTag(CLASS)) {
5143                         chk.checkNotRepeated(bound.pos(), types.erasure(bound.type), boundSet);
5144                     }
5145                 }
5146             }
5147         }
5148 
5149         if (bounds.length() == 0) {
5150             return syms.objectType;
5151         } else if (bounds.length() == 1) {
5152             return bounds.head.type;
5153         } else {
5154             Type owntype = types.makeIntersectionType(TreeInfo.types(bounds));
5155             // ... the variable's bound is a class type flagged COMPOUND
5156             // (see comment for TypeVar.bound).
5157             // In this case, generate a class tree that represents the
5158             // bound class, ...
5159             JCExpression extending;
5160             List<JCExpression> implementing;
5161             if (!bounds.head.type.isInterface()) {
5162                 extending = bounds.head;
5163                 implementing = bounds.tail;
5164             } else {
5165                 extending = null;
5166                 implementing = bounds;
5167             }
5168             JCClassDecl cd = make.at(tree).ClassDef(
5169                 make.Modifiers(PUBLIC | ABSTRACT),
5170                 names.empty, List.nil(),
5171                 extending, implementing, List.nil());
5172 
5173             ClassSymbol c = (ClassSymbol)owntype.tsym;
5174             Assert.check((c.flags() & COMPOUND) != 0);
5175             cd.sym = c;
5176             c.sourcefile = env.toplevel.sourcefile;
5177 
5178             // ... and attribute the bound class
5179             c.flags_field |= UNATTRIBUTED;
5180             Env<AttrContext> cenv = enter.classEnv(cd, env);
5181             typeEnvs.put(c, cenv);
5182             attribClass(c);
5183             return owntype;
5184         }
5185     }
5186 
5187     public void visitWildcard(JCWildcard tree) {
5188         //- System.err.println("visitWildcard("+tree+");");//DEBUG
5189         Type type = (tree.kind.kind == BoundKind.UNBOUND)
5190             ? syms.objectType
5191             : attribType(tree.inner, env);
5192         result = check(tree, new WildcardType(chk.checkRefType(tree.pos(), type),
5193                                               tree.kind.kind,
5194                                               syms.boundClass),
5195                 KindSelector.TYP, resultInfo);
5196     }
5197 
5198     public void visitAnnotation(JCAnnotation tree) {
5199         Assert.error("should be handled in annotate");
5200     }
5201 
5202     @Override
5203     public void visitModifiers(JCModifiers tree) {
5204         //error recovery only:
5205         Assert.check(resultInfo.pkind == KindSelector.ERR);
5206 
5207         attribAnnotationTypes(tree.annotations, env);
5208     }
5209 
5210     public void visitAnnotatedType(JCAnnotatedType tree) {
5211         attribAnnotationTypes(tree.annotations, env);
5212         Type underlyingType = attribType(tree.underlyingType, env);
5213         Type annotatedType = underlyingType.annotatedType(Annotations.TO_BE_SET);
5214 
5215         if (!env.info.isNewClass)
5216             annotate.annotateTypeSecondStage(tree, tree.annotations, annotatedType);
5217         result = tree.type = annotatedType;
5218     }
5219 
5220     public void visitErroneous(JCErroneous tree) {
5221         if (tree.errs != null) {
5222             Env<AttrContext> errEnv = env.dup(env.tree);
5223             errEnv.info.returnResult = unknownExprInfo;
5224             for (JCTree err : tree.errs)
5225                 attribTree(err, errEnv, new ResultInfo(KindSelector.ERR, pt()));
5226         }
5227         result = tree.type = syms.errType;
5228     }
5229 
5230     /** Default visitor method for all other trees.
5231      */
5232     public void visitTree(JCTree tree) {
5233         throw new AssertionError();
5234     }
5235 
5236     /**
5237      * Attribute an env for either a top level tree or class or module declaration.
5238      */
5239     public void attrib(Env<AttrContext> env) {
5240         switch (env.tree.getTag()) {
5241             case MODULEDEF:
5242                 attribModule(env.tree.pos(), ((JCModuleDecl)env.tree).sym);
5243                 break;
5244             case PACKAGEDEF:
5245                 attribPackage(env.tree.pos(), ((JCPackageDecl) env.tree).packge);
5246                 break;
5247             default:
5248                 attribClass(env.tree.pos(), env.enclClass.sym);
5249         }
5250     }
5251 
5252     public void attribPackage(DiagnosticPosition pos, PackageSymbol p) {
5253         try {
5254             annotate.flush();
5255             attribPackage(p);
5256         } catch (CompletionFailure ex) {
5257             chk.completionError(pos, ex);
5258         }
5259     }
5260 
5261     void attribPackage(PackageSymbol p) {
5262         attribWithLint(p,
5263                        env -> chk.checkDeprecatedAnnotation(((JCPackageDecl) env.tree).pid.pos(), p));
5264     }
5265 
5266     public void attribModule(DiagnosticPosition pos, ModuleSymbol m) {
5267         try {
5268             annotate.flush();
5269             attribModule(m);
5270         } catch (CompletionFailure ex) {
5271             chk.completionError(pos, ex);
5272         }
5273     }
5274 
5275     void attribModule(ModuleSymbol m) {
5276         attribWithLint(m, env -> attribStat(env.tree, env));
5277     }
5278 
5279     private void attribWithLint(TypeSymbol sym, Consumer<Env<AttrContext>> attrib) {
5280         Env<AttrContext> env = typeEnvs.get(sym);
5281 
5282         Env<AttrContext> lintEnv = env;
5283         while (lintEnv.info.lint == null)
5284             lintEnv = lintEnv.next;
5285 
5286         Lint lint = lintEnv.info.lint.augment(sym);
5287 
5288         Lint prevLint = chk.setLint(lint);
5289         JavaFileObject prev = log.useSource(env.toplevel.sourcefile);
5290 
5291         try {
5292             deferredLintHandler.flush(env.tree.pos());
5293             attrib.accept(env);
5294         } finally {
5295             log.useSource(prev);
5296             chk.setLint(prevLint);
5297         }
5298     }
5299 
5300     /** Main method: attribute class definition associated with given class symbol.
5301      *  reporting completion failures at the given position.
5302      *  @param pos The source position at which completion errors are to be
5303      *             reported.
5304      *  @param c   The class symbol whose definition will be attributed.
5305      */
5306     public void attribClass(DiagnosticPosition pos, ClassSymbol c) {
5307         try {
5308             annotate.flush();
5309             attribClass(c);
5310         } catch (CompletionFailure ex) {
5311             chk.completionError(pos, ex);
5312         }
5313     }
5314 
5315     /** Attribute class definition associated with given class symbol.
5316      *  @param c   The class symbol whose definition will be attributed.
5317      */
5318     void attribClass(ClassSymbol c) throws CompletionFailure {
5319         if (c.type.hasTag(ERROR)) return;
5320 
5321         // Check for cycles in the inheritance graph, which can arise from
5322         // ill-formed class files.
5323         chk.checkNonCyclic(null, c.type);
5324 
5325         Type st = types.supertype(c.type);
5326         if ((c.flags_field & Flags.COMPOUND) == 0 &&
5327             (c.flags_field & Flags.SUPER_OWNER_ATTRIBUTED) == 0) {
5328             // First, attribute superclass.
5329             if (st.hasTag(CLASS))
5330                 attribClass((ClassSymbol)st.tsym);
5331 
5332             // Next attribute owner, if it is a class.
5333             if (c.owner.kind == TYP && c.owner.type.hasTag(CLASS))
5334                 attribClass((ClassSymbol)c.owner);
5335 
5336             c.flags_field |= Flags.SUPER_OWNER_ATTRIBUTED;
5337         }
5338 
5339         // The previous operations might have attributed the current class
5340         // if there was a cycle. So we test first whether the class is still
5341         // UNATTRIBUTED.
5342         if ((c.flags_field & UNATTRIBUTED) != 0) {
5343             c.flags_field &= ~UNATTRIBUTED;
5344 
5345             // Get environment current at the point of class definition.
5346             Env<AttrContext> env = typeEnvs.get(c);
5347 
5348             if (c.isSealed() &&
5349                     !c.isEnum() &&
5350                     !c.isPermittedExplicit &&
5351                     c.permitted.isEmpty()) {
5352                 log.error(TreeInfo.diagnosticPositionFor(c, env.tree), Errors.SealedClassMustHaveSubclasses);
5353             }
5354 
5355             if (c.isSealed()) {
5356                 Set<Symbol> permittedTypes = new HashSet<>();
5357                 boolean sealedInUnnamed = c.packge().modle == syms.unnamedModule || c.packge().modle == syms.noModule;
5358                 for (Symbol subTypeSym : c.permitted) {
5359                     boolean isTypeVar = false;
5360                     if (subTypeSym.type.getTag() == TYPEVAR) {
5361                         isTypeVar = true; //error recovery
5362                         log.error(TreeInfo.diagnosticPositionFor(subTypeSym, env.tree),
5363                                 Errors.InvalidPermitsClause(Fragments.IsATypeVariable(subTypeSym.type)));
5364                     }
5365                     if (subTypeSym.isAnonymous() && !c.isEnum()) {
5366                         log.error(TreeInfo.diagnosticPositionFor(subTypeSym, env.tree),  Errors.LocalClassesCantExtendSealed(Fragments.Anonymous));
5367                     }
5368                     if (permittedTypes.contains(subTypeSym)) {
5369                         DiagnosticPosition pos =
5370                                 env.enclClass.permitting.stream()
5371                                         .filter(permittedExpr -> TreeInfo.diagnosticPositionFor(subTypeSym, permittedExpr, true) != null)
5372                                         .limit(2).collect(List.collector()).get(1);
5373                         log.error(pos, Errors.InvalidPermitsClause(Fragments.IsDuplicated(subTypeSym.type)));
5374                     } else {
5375                         permittedTypes.add(subTypeSym);
5376                     }
5377                     if (sealedInUnnamed) {
5378                         if (subTypeSym.packge() != c.packge()) {
5379                             log.error(TreeInfo.diagnosticPositionFor(subTypeSym, env.tree),
5380                                     Errors.ClassInUnnamedModuleCantExtendSealedInDiffPackage(c)
5381                             );
5382                         }
5383                     } else if (subTypeSym.packge().modle != c.packge().modle) {
5384                         log.error(TreeInfo.diagnosticPositionFor(subTypeSym, env.tree),
5385                                 Errors.ClassInModuleCantExtendSealedInDiffModule(c, c.packge().modle)
5386                         );
5387                     }
5388                     if (subTypeSym == c.type.tsym || types.isSuperType(subTypeSym.type, c.type)) {
5389                         log.error(TreeInfo.diagnosticPositionFor(subTypeSym, ((JCClassDecl)env.tree).permitting),
5390                                 Errors.InvalidPermitsClause(
5391                                         subTypeSym == c.type.tsym ?
5392                                                 Fragments.MustNotBeSameClass :
5393                                                 Fragments.MustNotBeSupertype(subTypeSym.type)
5394                                 )
5395                         );
5396                     } else if (!isTypeVar) {
5397                         boolean thisIsASuper = types.directSupertypes(subTypeSym.type)
5398                                                     .stream()
5399                                                     .anyMatch(d -> d.tsym == c);
5400                         if (!thisIsASuper) {
5401                             log.error(TreeInfo.diagnosticPositionFor(subTypeSym, env.tree),
5402                                     Errors.InvalidPermitsClause(Fragments.DoesntExtendSealed(subTypeSym.type)));
5403                         }
5404                     }
5405                 }
5406             }
5407 
5408             List<ClassSymbol> sealedSupers = types.directSupertypes(c.type)
5409                                                   .stream()
5410                                                   .filter(s -> s.tsym.isSealed())
5411                                                   .map(s -> (ClassSymbol) s.tsym)
5412                                                   .collect(List.collector());
5413 
5414             if (sealedSupers.isEmpty()) {
5415                 if ((c.flags_field & Flags.NON_SEALED) != 0) {
5416                     boolean hasErrorSuper = false;
5417 
5418                     hasErrorSuper |= types.directSupertypes(c.type)
5419                                           .stream()
5420                                           .anyMatch(s -> s.tsym.kind == Kind.ERR);
5421 
5422                     ClassType ct = (ClassType) c.type;
5423 
5424                     hasErrorSuper |= !ct.isCompound() && ct.interfaces_field != ct.all_interfaces_field;
5425 
5426                     if (!hasErrorSuper) {
5427                         log.error(TreeInfo.diagnosticPositionFor(c, env.tree), Errors.NonSealedWithNoSealedSupertype(c));
5428                     }
5429                 }
5430             } else {
5431                 if (c.isDirectlyOrIndirectlyLocal() && !c.isEnum()) {
5432                     log.error(TreeInfo.diagnosticPositionFor(c, env.tree), Errors.LocalClassesCantExtendSealed(c.isAnonymous() ? Fragments.Anonymous : Fragments.Local));
5433                 }
5434 
5435                 if (!c.type.isCompound()) {
5436                     for (ClassSymbol supertypeSym : sealedSupers) {
5437                         if (!supertypeSym.permitted.contains(c.type.tsym)) {
5438                             log.error(TreeInfo.diagnosticPositionFor(c.type.tsym, env.tree), Errors.CantInheritFromSealed(supertypeSym));
5439                         }
5440                     }
5441                     if (!c.isNonSealed() && !c.isFinal() && !c.isSealed()) {
5442                         log.error(TreeInfo.diagnosticPositionFor(c, env.tree),
5443                                 c.isInterface() ?
5444                                         Errors.NonSealedOrSealedExpected :
5445                                         Errors.NonSealedSealedOrFinalExpected);
5446                     }
5447                 }
5448             }
5449 
5450             // The info.lint field in the envs stored in typeEnvs is deliberately uninitialized,
5451             // because the annotations were not available at the time the env was created. Therefore,
5452             // we look up the environment chain for the first enclosing environment for which the
5453             // lint value is set. Typically, this is the parent env, but might be further if there
5454             // are any envs created as a result of TypeParameter nodes.
5455             Env<AttrContext> lintEnv = env;
5456             while (lintEnv.info.lint == null)
5457                 lintEnv = lintEnv.next;
5458 
5459             // Having found the enclosing lint value, we can initialize the lint value for this class
5460             env.info.lint = lintEnv.info.lint.augment(c);
5461 
5462             Lint prevLint = chk.setLint(env.info.lint);
5463             JavaFileObject prev = log.useSource(c.sourcefile);
5464             ResultInfo prevReturnRes = env.info.returnResult;
5465 
5466             try {
5467                 deferredLintHandler.flush(env.tree);
5468                 env.info.returnResult = null;
5469                 // java.lang.Enum may not be subclassed by a non-enum
5470                 if (st.tsym == syms.enumSym &&
5471                     ((c.flags_field & (Flags.ENUM|Flags.COMPOUND)) == 0))
5472                     log.error(env.tree.pos(), Errors.EnumNoSubclassing);
5473 
5474                 // Enums may not be extended by source-level classes
5475                 if (st.tsym != null &&
5476                     ((st.tsym.flags_field & Flags.ENUM) != 0) &&
5477                     ((c.flags_field & (Flags.ENUM | Flags.COMPOUND)) == 0)) {
5478                     log.error(env.tree.pos(), Errors.EnumTypesNotExtensible);
5479                 }
5480 
5481                 if (rs.isSerializable(c.type)) {
5482                     env.info.isSerializable = true;
5483                 }
5484 
5485                 attribClassBody(env, c);
5486 
5487                 chk.checkDeprecatedAnnotation(env.tree.pos(), c);
5488                 chk.checkClassOverrideEqualsAndHashIfNeeded(env.tree.pos(), c);
5489                 chk.checkFunctionalInterface((JCClassDecl) env.tree, c);
5490                 chk.checkLeaksNotAccessible(env, (JCClassDecl) env.tree);
5491             } finally {
5492                 env.info.returnResult = prevReturnRes;
5493                 log.useSource(prev);
5494                 chk.setLint(prevLint);
5495             }
5496 
5497         }
5498     }
5499 
5500     public void visitImport(JCImport tree) {
5501         // nothing to do
5502     }
5503 
5504     public void visitModuleDef(JCModuleDecl tree) {
5505         tree.sym.completeUsesProvides();
5506         ModuleSymbol msym = tree.sym;
5507         Lint lint = env.outer.info.lint = env.outer.info.lint.augment(msym);
5508         Lint prevLint = chk.setLint(lint);
5509         chk.checkModuleName(tree);
5510         chk.checkDeprecatedAnnotation(tree, msym);
5511 
5512         try {
5513             deferredLintHandler.flush(tree.pos());
5514         } finally {
5515             chk.setLint(prevLint);
5516         }
5517     }
5518 
5519     /** Finish the attribution of a class. */
5520     private void attribClassBody(Env<AttrContext> env, ClassSymbol c) {
5521         JCClassDecl tree = (JCClassDecl)env.tree;
5522         Assert.check(c == tree.sym);
5523 
5524         // Validate type parameters, supertype and interfaces.
5525         attribStats(tree.typarams, env);
5526         if (!c.isAnonymous()) {
5527             //already checked if anonymous
5528             chk.validate(tree.typarams, env);
5529             chk.validate(tree.extending, env);
5530             chk.validate(tree.implementing, env);
5531         }
5532 
5533         c.markAbstractIfNeeded(types);
5534 
5535         // If this is a non-abstract class, check that it has no abstract
5536         // methods or unimplemented methods of an implemented interface.
5537         if ((c.flags() & (ABSTRACT | INTERFACE)) == 0) {
5538             chk.checkAllDefined(tree.pos(), c);
5539         }
5540 
5541         if ((c.flags() & ANNOTATION) != 0) {
5542             if (tree.implementing.nonEmpty())
5543                 log.error(tree.implementing.head.pos(),
5544                           Errors.CantExtendIntfAnnotation);
5545             if (tree.typarams.nonEmpty()) {
5546                 log.error(tree.typarams.head.pos(),
5547                           Errors.IntfAnnotationCantHaveTypeParams(c));
5548             }
5549 
5550             // If this annotation type has a @Repeatable, validate
5551             Attribute.Compound repeatable = c.getAnnotationTypeMetadata().getRepeatable();
5552             // If this annotation type has a @Repeatable, validate
5553             if (repeatable != null) {
5554                 // get diagnostic position for error reporting
5555                 DiagnosticPosition cbPos = getDiagnosticPosition(tree, repeatable.type);
5556                 Assert.checkNonNull(cbPos);
5557 
5558                 chk.validateRepeatable(c, repeatable, cbPos);
5559             }
5560         } else {
5561             // Check that all extended classes and interfaces
5562             // are compatible (i.e. no two define methods with same arguments
5563             // yet different return types).  (JLS 8.4.8.3)
5564             chk.checkCompatibleSupertypes(tree.pos(), c.type);
5565             chk.checkDefaultMethodClashes(tree.pos(), c.type);
5566         }
5567 
5568         // Check that class does not import the same parameterized interface
5569         // with two different argument lists.
5570         chk.checkClassBounds(tree.pos(), c.type);
5571 
5572         tree.type = c.type;
5573 
5574         for (List<JCTypeParameter> l = tree.typarams;
5575              l.nonEmpty(); l = l.tail) {
5576              Assert.checkNonNull(env.info.scope.findFirst(l.head.name));
5577         }
5578 
5579         // Check that a generic class doesn't extend Throwable
5580         if (!c.type.allparams().isEmpty() && types.isSubtype(c.type, syms.throwableType))
5581             log.error(tree.extending.pos(), Errors.GenericThrowable);
5582 
5583         // Check that all methods which implement some
5584         // method conform to the method they implement.
5585         chk.checkImplementations(tree);
5586 
5587         //check that a resource implementing AutoCloseable cannot throw InterruptedException
5588         checkAutoCloseable(tree.pos(), env, c.type);
5589 
5590         for (List<JCTree> l = tree.defs; l.nonEmpty(); l = l.tail) {
5591             // Attribute declaration
5592             attribStat(l.head, env);
5593             // Check that declarations in inner classes are not static (JLS 8.1.2)
5594             // Make an exception for static constants.
5595             if (!allowRecords &&
5596                     c.owner.kind != PCK &&
5597                     ((c.flags() & STATIC) == 0 || c.name == names.empty) &&
5598                     (TreeInfo.flags(l.head) & (STATIC | INTERFACE)) != 0) {
5599                 VarSymbol sym = null;
5600                 if (l.head.hasTag(VARDEF)) sym = ((JCVariableDecl) l.head).sym;
5601                 if (sym == null ||
5602                         sym.kind != VAR ||
5603                         sym.getConstValue() == null)
5604                     log.error(l.head.pos(), Errors.IclsCantHaveStaticDecl(c));
5605             }
5606         }
5607 
5608         // Check for cycles among non-initial constructors.
5609         chk.checkCyclicConstructors(tree);
5610 
5611         // Check for cycles among annotation elements.
5612         chk.checkNonCyclicElements(tree);
5613 
5614         // Check for proper use of serialVersionUID and other
5615         // serialization-related fields and methods
5616         if (env.info.lint.isEnabled(LintCategory.SERIAL)
5617                 && rs.isSerializable(c.type)
5618                 && !c.isAnonymous()) {
5619             chk.checkSerialStructure(tree, c);
5620         }
5621         // Correctly organize the positions of the type annotations
5622         typeAnnotations.organizeTypeAnnotationsBodies(tree);
5623 
5624         // Check type annotations applicability rules
5625         validateTypeAnnotations(tree, false);
5626     }
5627         // where
5628         /** get a diagnostic position for an attribute of Type t, or null if attribute missing */
5629         private DiagnosticPosition getDiagnosticPosition(JCClassDecl tree, Type t) {
5630             for(List<JCAnnotation> al = tree.mods.annotations; !al.isEmpty(); al = al.tail) {
5631                 if (types.isSameType(al.head.annotationType.type, t))
5632                     return al.head.pos();
5633             }
5634 
5635             return null;
5636         }
5637 
5638     private Type capture(Type type) {
5639         return types.capture(type);
5640     }
5641 
5642     private void setSyntheticVariableType(JCVariableDecl tree, Type type) {
5643         if (type.isErroneous()) {
5644             tree.vartype = make.at(Position.NOPOS).Erroneous();
5645         } else {
5646             tree.vartype = make.at(Position.NOPOS).Type(type);
5647         }
5648     }
5649 
5650     public void validateTypeAnnotations(JCTree tree, boolean sigOnly) {
5651         tree.accept(new TypeAnnotationsValidator(sigOnly));
5652     }
5653     //where
5654     private final class TypeAnnotationsValidator extends TreeScanner {
5655 
5656         private final boolean sigOnly;
5657         public TypeAnnotationsValidator(boolean sigOnly) {
5658             this.sigOnly = sigOnly;
5659         }
5660 
5661         public void visitAnnotation(JCAnnotation tree) {
5662             chk.validateTypeAnnotation(tree, false);
5663             super.visitAnnotation(tree);
5664         }
5665         public void visitAnnotatedType(JCAnnotatedType tree) {
5666             if (!tree.underlyingType.type.isErroneous()) {
5667                 super.visitAnnotatedType(tree);
5668             }
5669         }
5670         public void visitTypeParameter(JCTypeParameter tree) {
5671             chk.validateTypeAnnotations(tree.annotations, true);
5672             scan(tree.bounds);
5673             // Don't call super.
5674             // This is needed because above we call validateTypeAnnotation with
5675             // false, which would forbid annotations on type parameters.
5676             // super.visitTypeParameter(tree);
5677         }
5678         public void visitMethodDef(JCMethodDecl tree) {
5679             if (tree.recvparam != null &&
5680                     !tree.recvparam.vartype.type.isErroneous()) {
5681                 checkForDeclarationAnnotations(tree.recvparam.mods.annotations, tree.recvparam.sym);
5682             }
5683             if (tree.restype != null && tree.restype.type != null) {
5684                 validateAnnotatedType(tree.restype, tree.restype.type);
5685             }
5686             if (sigOnly) {
5687                 scan(tree.mods);
5688                 scan(tree.restype);
5689                 scan(tree.typarams);
5690                 scan(tree.recvparam);
5691                 scan(tree.params);
5692                 scan(tree.thrown);
5693             } else {
5694                 scan(tree.defaultValue);
5695                 scan(tree.body);
5696             }
5697         }
5698         public void visitVarDef(final JCVariableDecl tree) {
5699             //System.err.println("validateTypeAnnotations.visitVarDef " + tree);
5700             if (tree.sym != null && tree.sym.type != null && !tree.isImplicitlyTyped())
5701                 validateAnnotatedType(tree.vartype, tree.sym.type);
5702             scan(tree.mods);
5703             scan(tree.vartype);
5704             if (!sigOnly) {
5705                 scan(tree.init);
5706             }
5707         }
5708         public void visitTypeCast(JCTypeCast tree) {
5709             if (tree.clazz != null && tree.clazz.type != null)
5710                 validateAnnotatedType(tree.clazz, tree.clazz.type);
5711             super.visitTypeCast(tree);
5712         }
5713         public void visitTypeTest(JCInstanceOf tree) {
5714             if (tree.pattern != null && !(tree.pattern instanceof JCPattern) && tree.pattern.type != null)
5715                 validateAnnotatedType(tree.pattern, tree.pattern.type);
5716             super.visitTypeTest(tree);
5717         }
5718         public void visitNewClass(JCNewClass tree) {
5719             if (tree.clazz != null && tree.clazz.type != null) {
5720                 if (tree.clazz.hasTag(ANNOTATED_TYPE)) {
5721                     checkForDeclarationAnnotations(((JCAnnotatedType) tree.clazz).annotations,
5722                             tree.clazz.type.tsym);
5723                 }
5724                 if (tree.def != null) {
5725                     checkForDeclarationAnnotations(tree.def.mods.annotations, tree.clazz.type.tsym);
5726                 }
5727 
5728                 validateAnnotatedType(tree.clazz, tree.clazz.type);
5729             }
5730             super.visitNewClass(tree);
5731         }
5732         public void visitNewArray(JCNewArray tree) {
5733             if (tree.elemtype != null && tree.elemtype.type != null) {
5734                 if (tree.elemtype.hasTag(ANNOTATED_TYPE)) {
5735                     checkForDeclarationAnnotations(((JCAnnotatedType) tree.elemtype).annotations,
5736                             tree.elemtype.type.tsym);
5737                 }
5738                 validateAnnotatedType(tree.elemtype, tree.elemtype.type);
5739             }
5740             super.visitNewArray(tree);
5741         }
5742         public void visitClassDef(JCClassDecl tree) {
5743             //System.err.println("validateTypeAnnotations.visitClassDef " + tree);
5744             if (sigOnly) {
5745                 scan(tree.mods);
5746                 scan(tree.typarams);
5747                 scan(tree.extending);
5748                 scan(tree.implementing);
5749             }
5750             for (JCTree member : tree.defs) {
5751                 if (member.hasTag(Tag.CLASSDEF)) {
5752                     continue;
5753                 }
5754                 scan(member);
5755             }
5756         }
5757         public void visitBlock(JCBlock tree) {
5758             if (!sigOnly) {
5759                 scan(tree.stats);
5760             }
5761         }
5762 
5763         /* I would want to model this after
5764          * com.sun.tools.javac.comp.Check.Validator.visitSelectInternal(JCFieldAccess)
5765          * and override visitSelect and visitTypeApply.
5766          * However, we only set the annotated type in the top-level type
5767          * of the symbol.
5768          * Therefore, we need to override each individual location where a type
5769          * can occur.
5770          */
5771         private void validateAnnotatedType(final JCTree errtree, final Type type) {
5772             //System.err.println("Attr.validateAnnotatedType: " + errtree + " type: " + type);
5773 
5774             if (type.isPrimitiveOrVoid()) {
5775                 return;
5776             }
5777 
5778             JCTree enclTr = errtree;
5779             Type enclTy = type;
5780 
5781             boolean repeat = true;
5782             while (repeat) {
5783                 if (enclTr.hasTag(TYPEAPPLY)) {
5784                     List<Type> tyargs = enclTy.getTypeArguments();
5785                     List<JCExpression> trargs = ((JCTypeApply)enclTr).getTypeArguments();
5786                     if (trargs.length() > 0) {
5787                         // Nothing to do for diamonds
5788                         if (tyargs.length() == trargs.length()) {
5789                             for (int i = 0; i < tyargs.length(); ++i) {
5790                                 validateAnnotatedType(trargs.get(i), tyargs.get(i));
5791                             }
5792                         }
5793                         // If the lengths don't match, it's either a diamond
5794                         // or some nested type that redundantly provides
5795                         // type arguments in the tree.
5796                     }
5797 
5798                     // Look at the clazz part of a generic type
5799                     enclTr = ((JCTree.JCTypeApply)enclTr).clazz;
5800                 }
5801 
5802                 if (enclTr.hasTag(SELECT)) {
5803                     enclTr = ((JCTree.JCFieldAccess)enclTr).getExpression();
5804                     if (enclTy != null &&
5805                             !enclTy.hasTag(NONE)) {
5806                         enclTy = enclTy.getEnclosingType();
5807                     }
5808                 } else if (enclTr.hasTag(ANNOTATED_TYPE)) {
5809                     JCAnnotatedType at = (JCTree.JCAnnotatedType) enclTr;
5810                     if (enclTy == null || enclTy.hasTag(NONE)) {
5811                         if (at.getAnnotations().size() == 1) {
5812                             log.error(at.underlyingType.pos(), Errors.CantTypeAnnotateScoping1(at.getAnnotations().head.attribute));
5813                         } else {
5814                             ListBuffer<Attribute.Compound> comps = new ListBuffer<>();
5815                             for (JCAnnotation an : at.getAnnotations()) {
5816                                 comps.add(an.attribute);
5817                             }
5818                             log.error(at.underlyingType.pos(), Errors.CantTypeAnnotateScoping(comps.toList()));
5819                         }
5820                         repeat = false;
5821                     }
5822                     enclTr = at.underlyingType;
5823                     // enclTy doesn't need to be changed
5824                 } else if (enclTr.hasTag(IDENT)) {
5825                     repeat = false;
5826                 } else if (enclTr.hasTag(JCTree.Tag.WILDCARD)) {
5827                     JCWildcard wc = (JCWildcard) enclTr;
5828                     if (wc.getKind() == JCTree.Kind.EXTENDS_WILDCARD ||
5829                             wc.getKind() == JCTree.Kind.SUPER_WILDCARD) {
5830                         validateAnnotatedType(wc.getBound(), wc.getBound().type);
5831                     } else {
5832                         // Nothing to do for UNBOUND
5833                     }
5834                     repeat = false;
5835                 } else if (enclTr.hasTag(TYPEARRAY)) {
5836                     JCArrayTypeTree art = (JCArrayTypeTree) enclTr;
5837                     validateAnnotatedType(art.getType(), art.elemtype.type);
5838                     repeat = false;
5839                 } else if (enclTr.hasTag(TYPEUNION)) {
5840                     JCTypeUnion ut = (JCTypeUnion) enclTr;
5841                     for (JCTree t : ut.getTypeAlternatives()) {
5842                         validateAnnotatedType(t, t.type);
5843                     }
5844                     repeat = false;
5845                 } else if (enclTr.hasTag(TYPEINTERSECTION)) {
5846                     JCTypeIntersection it = (JCTypeIntersection) enclTr;
5847                     for (JCTree t : it.getBounds()) {
5848                         validateAnnotatedType(t, t.type);
5849                     }
5850                     repeat = false;
5851                 } else if (enclTr.getKind() == JCTree.Kind.PRIMITIVE_TYPE ||
5852                            enclTr.getKind() == JCTree.Kind.ERRONEOUS) {
5853                     repeat = false;
5854                 } else {
5855                     Assert.error("Unexpected tree: " + enclTr + " with kind: " + enclTr.getKind() +
5856                             " within: "+ errtree + " with kind: " + errtree.getKind());
5857                 }
5858             }
5859         }
5860 
5861         private void checkForDeclarationAnnotations(List<? extends JCAnnotation> annotations,
5862                 Symbol sym) {
5863             // Ensure that no declaration annotations are present.
5864             // Note that a tree type might be an AnnotatedType with
5865             // empty annotations, if only declaration annotations were given.
5866             // This method will raise an error for such a type.
5867             for (JCAnnotation ai : annotations) {
5868                 if (!ai.type.isErroneous() &&
5869                         typeAnnotations.annotationTargetType(ai.attribute, sym) == TypeAnnotations.AnnotationType.DECLARATION) {
5870                     log.error(ai.pos(), Errors.AnnotationTypeNotApplicableToType(ai.type));
5871                 }
5872             }
5873         }
5874     }
5875 
5876     // <editor-fold desc="post-attribution visitor">
5877 
5878     /**
5879      * Handle missing types/symbols in an AST. This routine is useful when
5880      * the compiler has encountered some errors (which might have ended up
5881      * terminating attribution abruptly); if the compiler is used in fail-over
5882      * mode (e.g. by an IDE) and the AST contains semantic errors, this routine
5883      * prevents NPE to be propagated during subsequent compilation steps.
5884      */
5885     public void postAttr(JCTree tree) {
5886         new PostAttrAnalyzer().scan(tree);
5887     }
5888 
5889     class PostAttrAnalyzer extends TreeScanner {
5890 
5891         private void initTypeIfNeeded(JCTree that) {
5892             if (that.type == null) {
5893                 if (that.hasTag(METHODDEF)) {
5894                     that.type = dummyMethodType((JCMethodDecl)that);
5895                 } else {
5896                     that.type = syms.unknownType;
5897                 }
5898             }
5899         }
5900 
5901         /* Construct a dummy method type. If we have a method declaration,
5902          * and the declared return type is void, then use that return type
5903          * instead of UNKNOWN to avoid spurious error messages in lambda
5904          * bodies (see:JDK-8041704).
5905          */
5906         private Type dummyMethodType(JCMethodDecl md) {
5907             Type restype = syms.unknownType;
5908             if (md != null && md.restype != null && md.restype.hasTag(TYPEIDENT)) {
5909                 JCPrimitiveTypeTree prim = (JCPrimitiveTypeTree)md.restype;
5910                 if (prim.typetag == VOID)
5911                     restype = syms.voidType;
5912             }
5913             return new MethodType(List.nil(), restype,
5914                                   List.nil(), syms.methodClass);
5915         }
5916         private Type dummyMethodType() {
5917             return dummyMethodType(null);
5918         }
5919 
5920         @Override
5921         public void scan(JCTree tree) {
5922             if (tree == null) return;
5923             if (tree instanceof JCExpression) {
5924                 initTypeIfNeeded(tree);
5925             }
5926             super.scan(tree);
5927         }
5928 
5929         @Override
5930         public void visitIdent(JCIdent that) {
5931             if (that.sym == null) {
5932                 that.sym = syms.unknownSymbol;
5933             }
5934         }
5935 
5936         @Override
5937         public void visitSelect(JCFieldAccess that) {
5938             if (that.sym == null) {
5939                 that.sym = syms.unknownSymbol;
5940             }
5941             super.visitSelect(that);
5942         }
5943 
5944         @Override
5945         public void visitClassDef(JCClassDecl that) {
5946             initTypeIfNeeded(that);
5947             if (that.sym == null) {
5948                 that.sym = new ClassSymbol(0, that.name, that.type, syms.noSymbol);
5949             }
5950             super.visitClassDef(that);
5951         }
5952 
5953         @Override
5954         public void visitMethodDef(JCMethodDecl that) {
5955             initTypeIfNeeded(that);
5956             if (that.sym == null) {
5957                 that.sym = new MethodSymbol(0, that.name, that.type, syms.noSymbol);
5958             }
5959             super.visitMethodDef(that);
5960         }
5961 
5962         @Override
5963         public void visitVarDef(JCVariableDecl that) {
5964             initTypeIfNeeded(that);
5965             if (that.sym == null) {
5966                 that.sym = new VarSymbol(0, that.name, that.type, syms.noSymbol);
5967                 that.sym.adr = 0;
5968             }
5969             if (that.vartype == null) {
5970                 that.vartype = make.at(Position.NOPOS).Erroneous();
5971             }
5972             super.visitVarDef(that);
5973         }
5974 
5975         @Override
5976         public void visitBindingPattern(JCBindingPattern that) {
5977             initTypeIfNeeded(that);
5978             initTypeIfNeeded(that.var);
5979             if (that.var.sym == null) {
5980                 that.var.sym = new BindingSymbol(0, that.var.name, that.var.type, syms.noSymbol);
5981                 that.var.sym.adr = 0;
5982             }
5983             super.visitBindingPattern(that);
5984         }
5985 
5986         @Override
5987         public void visitNewClass(JCNewClass that) {
5988             if (that.constructor == null) {
5989                 that.constructor = new MethodSymbol(0, names.init,
5990                         dummyMethodType(), syms.noSymbol);
5991             }
5992             if (that.constructorType == null) {
5993                 that.constructorType = syms.unknownType;
5994             }
5995             super.visitNewClass(that);
5996         }
5997 
5998         @Override
5999         public void visitAssignop(JCAssignOp that) {
6000             if (that.operator == null) {
6001                 that.operator = new OperatorSymbol(names.empty, dummyMethodType(),
6002                         -1, syms.noSymbol);
6003             }
6004             super.visitAssignop(that);
6005         }
6006 
6007         @Override
6008         public void visitBinary(JCBinary that) {
6009             if (that.operator == null) {
6010                 that.operator = new OperatorSymbol(names.empty, dummyMethodType(),
6011                         -1, syms.noSymbol);
6012             }
6013             super.visitBinary(that);
6014         }
6015 
6016         @Override
6017         public void visitUnary(JCUnary that) {
6018             if (that.operator == null) {
6019                 that.operator = new OperatorSymbol(names.empty, dummyMethodType(),
6020                         -1, syms.noSymbol);
6021             }
6022             super.visitUnary(that);
6023         }
6024 
6025         @Override
6026         public void visitReference(JCMemberReference that) {
6027             super.visitReference(that);
6028             if (that.sym == null) {
6029                 that.sym = new MethodSymbol(0, names.empty, dummyMethodType(),
6030                         syms.noSymbol);
6031             }
6032         }
6033     }
6034     // </editor-fold>
6035 
6036     public void setPackageSymbols(JCExpression pid, Symbol pkg) {
6037         new TreeScanner() {
6038             Symbol packge = pkg;
6039             @Override
6040             public void visitIdent(JCIdent that) {
6041                 that.sym = packge;
6042             }
6043 
6044             @Override
6045             public void visitSelect(JCFieldAccess that) {
6046                 that.sym = packge;
6047                 packge = packge.owner;
6048                 super.visitSelect(that);
6049             }
6050         }.scan(pid);
6051     }
6052 
6053 }