1 /*
2 * Copyright (c) 2015, 2017, 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 com.sun.tools.javac.code.Flags;
29 import com.sun.tools.javac.code.Symbol;
30 import com.sun.tools.javac.code.Symtab;
31 import com.sun.tools.javac.code.Type;
32 import com.sun.tools.javac.code.Types.FunctionDescriptorLookupError;
33 import com.sun.tools.javac.comp.Attr.ResultInfo;
34 import com.sun.tools.javac.comp.Attr.TargetInfo;
35 import com.sun.tools.javac.comp.Check.CheckContext;
36 import com.sun.tools.javac.comp.DeferredAttr.AttrMode;
37 import com.sun.tools.javac.comp.DeferredAttr.DeferredAttrContext;
38 import com.sun.tools.javac.comp.DeferredAttr.DeferredType;
39 import com.sun.tools.javac.comp.DeferredAttr.DeferredTypeCompleter;
40 import com.sun.tools.javac.comp.DeferredAttr.LambdaReturnScanner;
41 import com.sun.tools.javac.comp.DeferredAttr.SwitchExpressionScanner;
42 import com.sun.tools.javac.comp.Infer.PartiallyInferredMethodType;
43 import com.sun.tools.javac.comp.Resolve.MethodResolutionPhase;
44 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
45 import com.sun.tools.javac.tree.JCTree;
46 import com.sun.tools.javac.tree.JCTree.JCBreak;
47 import com.sun.tools.javac.tree.JCTree.JCConditional;
48 import com.sun.tools.javac.tree.JCTree.JCExpression;
49 import com.sun.tools.javac.tree.JCTree.JCLambda;
50 import com.sun.tools.javac.tree.JCTree.JCLambda.ParameterKind;
51 import com.sun.tools.javac.tree.JCTree.JCMemberReference;
52 import com.sun.tools.javac.tree.JCTree.JCMethodInvocation;
53 import com.sun.tools.javac.tree.JCTree.JCNewClass;
54 import com.sun.tools.javac.tree.JCTree.JCParens;
55 import com.sun.tools.javac.tree.JCTree.JCReturn;
56 import com.sun.tools.javac.tree.JCTree.JCSwitchExpression;
57 import com.sun.tools.javac.tree.TreeCopier;
58 import com.sun.tools.javac.tree.TreeInfo;
59 import com.sun.tools.javac.util.Assert;
60 import com.sun.tools.javac.util.Context;
61 import com.sun.tools.javac.util.DiagnosticSource;
62 import com.sun.tools.javac.util.JCDiagnostic;
63 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
64 import com.sun.tools.javac.util.List;
65 import com.sun.tools.javac.util.ListBuffer;
66 import com.sun.tools.javac.util.Log;
67
68 import java.util.HashMap;
69 import java.util.LinkedHashMap;
70 import java.util.Map;
71 import java.util.Optional;
72 import java.util.function.Function;
73 import java.util.function.Supplier;
74
75 import static com.sun.tools.javac.code.TypeTag.ARRAY;
76 import static com.sun.tools.javac.code.TypeTag.DEFERRED;
77 import static com.sun.tools.javac.code.TypeTag.FORALL;
78 import static com.sun.tools.javac.code.TypeTag.METHOD;
79 import static com.sun.tools.javac.code.TypeTag.VOID;
80
81 /**
82 * This class performs attribution of method/constructor arguments when target-typing is enabled
83 * (source >= 8); for each argument that is potentially a poly expression, this class builds
84 * a rich representation (see {@link ArgumentType} which can then be used for performing fast overload
85 * checks without requiring multiple attribution passes over the same code.
86 *
87 * The attribution strategy for a given method/constructor argument A is as follows:
88 *
89 * - if A is potentially a poly expression (i.e. diamond instance creation expression), a speculative
90 * pass over A is performed; the results of such speculative attribution are then saved in a special
91 * type, so that enclosing overload resolution can be carried by simply checking compatibility against the
92 * type determined during this speculative pass.
93 *
94 * - if A is a standalone expression, regular atributtion takes place.
95 *
96 * To minimize the speculative work, a cache is used, so that already computed argument types
97 * associated with a given unique source location are never recomputed multiple times.
98 */
99 public class ArgumentAttr extends JCTree.Visitor {
100
101 protected static final Context.Key<ArgumentAttr> methodAttrKey = new Context.Key<>();
102
103 private final DeferredAttr deferredAttr;
104 private final JCDiagnostic.Factory diags;
105 private final Attr attr;
106 private final Symtab syms;
107 private final Log log;
108
109 /** Attribution environment to be used. */
110 private Env<AttrContext> env;
111
112 /** Result of method attribution. */
113 Type result;
114
115 /** Cache for argument types; behavior is influences by the currrently selected cache policy. */
116 Map<UniquePos, ArgumentType<?>> argumentTypeCache = new LinkedHashMap<>();
117
118 public static ArgumentAttr instance(Context context) {
119 ArgumentAttr instance = context.get(methodAttrKey);
120 if (instance == null)
121 instance = new ArgumentAttr(context);
122 return instance;
123 }
124
125 protected ArgumentAttr(Context context) {
126 context.put(methodAttrKey, this);
127 deferredAttr = DeferredAttr.instance(context);
128 diags = JCDiagnostic.Factory.instance(context);
129 attr = Attr.instance(context);
130 syms = Symtab.instance(context);
131 log = Log.instance(context);
132 }
133
134 /**
135 * Set the results of method attribution.
136 */
137 void setResult(JCExpression tree, Type type) {
138 result = type;
139 if (env.info.isSpeculative) {
140 //if we are in a speculative branch we can save the type in the tree itself
141 //as there's no risk of polluting the original tree.
142 tree.type = result;
143 }
144 }
145
146 /**
147 * Checks a type in the speculative tree against a given result; the type can be either a plain
148 * type or an argument type,in which case a more complex check is required.
149 */
150 Type checkSpeculative(JCTree expr, ResultInfo resultInfo) {
151 return checkSpeculative(expr, expr.type, resultInfo);
152 }
153
154 /**
155 * Checks a type in the speculative tree against a given result; the type can be either a plain
156 * type or an argument type,in which case a more complex check is required.
157 */
158 Type checkSpeculative(DiagnosticPosition pos, Type t, ResultInfo resultInfo) {
159 if (t.hasTag(DEFERRED)) {
160 return ((DeferredType)t).check(resultInfo);
161 } else {
162 return resultInfo.check(pos, t);
163 }
164 }
165
166 /**
167 * Returns a local caching context in which argument types can safely be cached without
168 * the risk of polluting enclosing contexts. This is useful when attempting speculative
169 * attribution of potentially erroneous expressions, which could end up polluting the cache.
170 */
171 LocalCacheContext withLocalCacheContext() {
172 return new LocalCacheContext();
173 }
174
175 /**
176 * Local cache context; this class keeps track of the previous cache and reverts to it
177 * when the {@link LocalCacheContext#leave()} method is called.
178 */
179 class LocalCacheContext {
180 Map<UniquePos, ArgumentType<?>> prevCache;
181
182 public LocalCacheContext() {
183 this.prevCache = argumentTypeCache;
184 argumentTypeCache = new HashMap<>();
185 }
186
187 public void leave() {
188 argumentTypeCache = prevCache;
189 }
190 }
191
192 /**
193 * Main entry point for attributing an argument with given tree and attribution environment.
194 */
195 Type attribArg(JCTree tree, Env<AttrContext> env) {
196 Env<AttrContext> prevEnv = this.env;
197 try {
198 this.env = env;
199 tree.accept(this);
200 return result;
201 } finally {
202 this.env = prevEnv;
203 }
204 }
205
206 @Override
207 public void visitTree(JCTree that) {
208 //delegates to Attr
209 that.accept(attr);
210 result = attr.result;
211 }
212
213 /**
214 * Process a method argument; this method takes care of performing a speculative pass over the
215 * argument tree and calling a well-defined entry point to build the argument type associated
216 * with such tree.
217 */
218 @SuppressWarnings("unchecked")
219 <T extends JCExpression, Z extends ArgumentType<T>> void processArg(T that, Function<T, Z> argumentTypeFactory) {
220 UniquePos pos = new UniquePos(that);
221 processArg(that, () -> {
222 T speculativeTree = (T)deferredAttr.attribSpeculative(that, env, attr.new MethodAttrInfo() {
223 @Override
224 protected boolean needsArgumentAttr(JCTree tree) {
225 return !new UniquePos(tree).equals(pos);
226 }
227 });
228 return argumentTypeFactory.apply(speculativeTree);
229 });
230 }
231
232 /**
233 * Process a method argument; this method allows the caller to specify a custom speculative attribution
234 * logic (this is used e.g. for lambdas).
235 */
236 @SuppressWarnings("unchecked")
237 <T extends JCExpression, Z extends ArgumentType<T>> void processArg(T that, Supplier<Z> argumentTypeFactory) {
238 UniquePos pos = new UniquePos(that);
239 Z cached = (Z)argumentTypeCache.get(pos);
240 if (cached != null) {
241 //dup existing speculative type
242 setResult(that, cached.dup(that, env));
243 } else {
244 Z res = argumentTypeFactory.get();
245 argumentTypeCache.put(pos, res);
246 setResult(that, res);
247 }
248 }
249
250 @Override
251 public void visitParens(JCParens that) {
252 processArg(that, speculativeTree -> new ParensType(that, env, speculativeTree));
253 }
254
255 @Override
256 public void visitConditional(JCConditional that) {
257 processArg(that, speculativeTree -> new ConditionalType(that, env, speculativeTree));
258 }
259
260 @Override
261 public void visitSwitchExpression(JCSwitchExpression that) {
262 processArg(that, speculativeTree -> new SwitchExpressionType(that, env, speculativeTree));
263 }
264
265 @Override
266 public void visitReference(JCMemberReference tree) {
267 //perform arity-based check
268 Env<AttrContext> localEnv = env.dup(tree);
269 JCExpression exprTree;
270 exprTree = (JCExpression)deferredAttr.attribSpeculative(tree.getQualifierExpression(), localEnv,
271 attr.memberReferenceQualifierResult(tree),
272 withLocalCacheContext());
273 JCMemberReference mref2 = new TreeCopier<Void>(attr.make).copy(tree);
274 mref2.expr = exprTree;
275 Symbol lhsSym = TreeInfo.symbol(exprTree);
276 localEnv.info.selectSuper = lhsSym != null && lhsSym.name == lhsSym.name.table.names._super;
277 Symbol res =
278 attr.rs.getMemberReference(tree, localEnv, mref2,
279 exprTree.type, tree.name);
280 if (!res.kind.isResolutionError()) {
281 tree.sym = res;
282 }
283 if (res.kind.isResolutionTargetError() ||
284 res.type != null && res.type.hasTag(FORALL) ||
285 (res.flags() & Flags.VARARGS) != 0 ||
286 (TreeInfo.isStaticSelector(exprTree, tree.name.table.names) &&
287 exprTree.type.isRaw() && !exprTree.type.hasTag(ARRAY))) {
288 tree.setOverloadKind(JCMemberReference.OverloadKind.OVERLOADED);
289 } else {
290 tree.setOverloadKind(JCMemberReference.OverloadKind.UNOVERLOADED);
291 }
292 //return a plain old deferred type for this
293 setResult(tree, deferredAttr.new DeferredType(tree, env));
294 }
295
296 @Override
297 public void visitLambda(JCLambda that) {
298 if (that.paramKind == ParameterKind.EXPLICIT) {
299 //if lambda is explicit, we can save info in the corresponding argument type
300 processArg(that, () -> {
301 JCLambda speculativeLambda =
302 deferredAttr.attribSpeculativeLambda(that, env, attr.methodAttrInfo);
303 return new ExplicitLambdaType(that, env, speculativeLambda);
304 });
305 } else {
306 //otherwise just use a deferred type
307 setResult(that, deferredAttr.new DeferredType(that, env));
308 }
309 }
310
311 @Override
312 public void visitApply(JCMethodInvocation that) {
313 if (that.getTypeArguments().isEmpty()) {
314 processArg(that, speculativeTree -> new ResolvedMethodType(that, env, speculativeTree));
315 } else {
316 //not a poly expression, just call Attr
317 setResult(that, attr.attribTree(that, env, attr.unknownExprInfo));
318 }
319 }
320
321 @Override
322 public void visitNewClass(JCNewClass that) {
323 if (TreeInfo.isDiamond(that)) {
324 processArg(that, speculativeTree -> new ResolvedConstructorType(that, env, speculativeTree));
325 } else {
326 //not a poly expression, just call Attr
327 setResult(that, attr.attribTree(that, env, attr.unknownExprInfo));
328 }
329 }
330
331 /**
332 * An argument type is similar to a plain deferred type; the most important difference is that
333 * the completion logic associated with argument types allows speculative attribution to be skipped
334 * during overload resolution - that is, an argument type always has enough information to
335 * perform an overload check without the need of calling back to Attr. This extra information
336 * is typically stored in the form of a speculative tree.
337 */
338 abstract class ArgumentType<T extends JCExpression> extends DeferredType implements DeferredTypeCompleter {
339
340 /** The speculative tree carrying type information. */
341 T speculativeTree;
342
343 /** Types associated with this argument (one type per possible target result). */
344 Map<ResultInfo, Type> speculativeTypes;
345
346 public ArgumentType(JCExpression tree, Env<AttrContext> env, T speculativeTree, Map<ResultInfo, Type> speculativeTypes) {
347 deferredAttr.super(tree, env);
348 this.speculativeTree = speculativeTree;
349 this.speculativeTypes = speculativeTypes;
350 }
351
352 @Override
353 final DeferredTypeCompleter completer() {
354 return this;
355 }
356
357 @Override
358 final public Type complete(DeferredType dt, ResultInfo resultInfo, DeferredAttrContext deferredAttrContext) {
359 Assert.check(dt == this);
360 if (deferredAttrContext.mode == AttrMode.SPECULATIVE) {
361 Type t = (resultInfo.pt == Type.recoveryType) ?
362 deferredAttr.basicCompleter.complete(dt, resultInfo, deferredAttrContext) :
363 overloadCheck(resultInfo, deferredAttrContext);
364 speculativeTypes.put(resultInfo, t);
365 return t;
366 } else {
367 if (!env.info.isSpeculative) {
368 argumentTypeCache.remove(new UniquePos(dt.tree));
369 }
370 return deferredAttr.basicCompleter.complete(dt, resultInfo, deferredAttrContext);
371 }
372 }
373
374 @Override
375 Type speculativeType(Symbol msym, MethodResolutionPhase phase) {
376 if (notPertinentToApplicability.contains(msym)) {
377 return super.speculativeType(msym, phase);
378 } else {
379 for (Map.Entry<ResultInfo, Type> _entry : speculativeTypes.entrySet()) {
380 DeferredAttrContext deferredAttrContext = _entry.getKey().checkContext.deferredAttrContext();
381 if (deferredAttrContext.phase == phase && deferredAttrContext.msym == msym) {
382 return _entry.getValue();
383 }
384 }
385 return Type.noType;
386 }
387 }
388
389 @Override
390 JCTree speculativeTree(DeferredAttrContext deferredAttrContext) {
391 return notPertinentToApplicability.contains(deferredAttrContext.msym) ?
392 super.speculativeTree(deferredAttrContext) :
393 speculativeTree;
394 }
395
396 /**
397 * Performs an overload check against a given target result.
398 */
399 abstract Type overloadCheck(ResultInfo resultInfo, DeferredAttrContext deferredAttrContext);
400
401 /**
402 * Creates a copy of this argument type with given tree and environment.
403 */
404 abstract ArgumentType<T> dup(T tree, Env<AttrContext> env);
405 }
406
407 /**
408 * Argument type for parenthesized expression.
409 */
410 class ParensType extends ArgumentType<JCParens> {
411 ParensType(JCExpression tree, Env<AttrContext> env, JCParens speculativeParens) {
412 this(tree, env, speculativeParens, new HashMap<>());
413 }
414
415 ParensType(JCExpression tree, Env<AttrContext> env, JCParens speculativeParens, Map<ResultInfo, Type> speculativeTypes) {
416 super(tree, env, speculativeParens, speculativeTypes);
417 }
418
419 @Override
420 Type overloadCheck(ResultInfo resultInfo, DeferredAttrContext deferredAttrContext) {
421 return checkSpeculative(speculativeTree.expr, resultInfo);
422 }
423
424 @Override
425 ArgumentType<JCParens> dup(JCParens tree, Env<AttrContext> env) {
426 return new ParensType(tree, env, speculativeTree, speculativeTypes);
427 }
428 }
429
430 /**
431 * Argument type for conditionals.
432 */
433 class ConditionalType extends ArgumentType<JCConditional> {
434 ConditionalType(JCExpression tree, Env<AttrContext> env, JCConditional speculativeCond) {
435 this(tree, env, speculativeCond, new HashMap<>());
436 }
437
438 ConditionalType(JCExpression tree, Env<AttrContext> env, JCConditional speculativeCond, Map<ResultInfo, Type> speculativeTypes) {
439 super(tree, env, speculativeCond, speculativeTypes);
440 }
441
442 @Override
443 Type overloadCheck(ResultInfo resultInfo, DeferredAttrContext deferredAttrContext) {
444 ResultInfo localInfo = resultInfo.dup(attr.conditionalContext(resultInfo.checkContext));
445 if (speculativeTree.isStandalone()) {
446 return localInfo.check(speculativeTree, speculativeTree.type);
447 } else if (resultInfo.pt.hasTag(VOID)) {
448 //this means we are returning a poly conditional from void-compatible lambda expression
449 resultInfo.checkContext.report(tree, attr.diags.fragment(Fragments.ConditionalTargetCantBeVoid));
450 return attr.types.createErrorType(resultInfo.pt);
451 } else {
452 //poly
453 checkSpeculative(speculativeTree.truepart, localInfo);
454 checkSpeculative(speculativeTree.falsepart, localInfo);
455 return localInfo.pt;
456 }
457 }
458
459 @Override
460 ArgumentType<JCConditional> dup(JCConditional tree, Env<AttrContext> env) {
461 return new ConditionalType(tree, env, speculativeTree, speculativeTypes);
462 }
463 }
464
465 /**
466 * Argument type for switch expressions.
467 */
468 class SwitchExpressionType extends ArgumentType<JCSwitchExpression> {
469 /** List of break expressions (lazily populated). */
470 Optional<List<JCBreak>> breakExpressions = Optional.empty();
471
472 SwitchExpressionType(JCExpression tree, Env<AttrContext> env, JCSwitchExpression speculativeCond) {
473 this(tree, env, speculativeCond, new HashMap<>());
474 }
475
476 SwitchExpressionType(JCExpression tree, Env<AttrContext> env, JCSwitchExpression speculativeCond, Map<ResultInfo, Type> speculativeTypes) {
477 super(tree, env, speculativeCond, speculativeTypes);
478 }
479
480 @Override
481 Type overloadCheck(ResultInfo resultInfo, DeferredAttrContext deferredAttrContext) {
482 ResultInfo localInfo = resultInfo.dup(attr.conditionalContext(resultInfo.checkContext));
483 if (resultInfo.pt.hasTag(VOID)) {
484 //this means we are returning a poly switch expression from void-compatible lambda expression
485 resultInfo.checkContext.report(tree, attr.diags.fragment(Fragments.SwitchExpressionTargetCantBeVoid));
486 return attr.types.createErrorType(resultInfo.pt);
487 } else {
488 //poly
489 for (JCBreak brk : breakExpressions()) {
490 checkSpeculative(brk.value, brk.value.type, resultInfo);
491 }
492 return localInfo.pt;
493 }
494 }
495
496 /** Compute return expressions (if needed). */
497 List<JCBreak> breakExpressions() {
498 return breakExpressions.orElseGet(() -> {
499 final List<JCBreak> res;
500 ListBuffer<JCBreak> buf = new ListBuffer<>();
501 new SwitchExpressionScanner() {
502 @Override
503 public void visitBreak(JCBreak tree) {
504 if (tree.target == speculativeTree)
505 buf.add(tree);
506 }
507 }.scan(speculativeTree.cases);
508 res = buf.toList();
509 breakExpressions = Optional.of(res);
510 return res;
511 });
512 }
513
514 @Override
515 ArgumentType<JCSwitchExpression> dup(JCSwitchExpression tree, Env<AttrContext> env) {
516 return new SwitchExpressionType(tree, env, speculativeTree, speculativeTypes);
517 }
518 }
519
520 /**
521 * Argument type for explicit lambdas.
522 */
523 class ExplicitLambdaType extends ArgumentType<JCLambda> {
524
525 /** List of argument types (lazily populated). */
526 Optional<List<Type>> argtypes = Optional.empty();
527
528 /** List of return expressions (lazily populated). */
529 Optional<List<JCReturn>> returnExpressions = Optional.empty();
530
531 ExplicitLambdaType(JCLambda originalLambda, Env<AttrContext> env, JCLambda speculativeLambda) {
532 this(originalLambda, env, speculativeLambda, new HashMap<>());
533 }
534
535 ExplicitLambdaType(JCLambda originalLambda, Env<AttrContext> env, JCLambda speculativeLambda, Map<ResultInfo, Type> speculativeTypes) {
536 super(originalLambda, env, speculativeLambda, speculativeTypes);
537 }
538
539 /** Compute argument types (if needed). */
540 List<Type> argtypes() {
541 return argtypes.orElseGet(() -> {
542 List<Type> res = TreeInfo.types(speculativeTree.params);
543 argtypes = Optional.of(res);
544 return res;
545 });
546 }
547
548 /** Compute return expressions (if needed). */
549 List<JCReturn> returnExpressions() {
550 return returnExpressions.orElseGet(() -> {
551 final List<JCReturn> res;
552 ListBuffer<JCReturn> buf = new ListBuffer<>();
553 new LambdaReturnScanner() {
554 @Override
555 public void visitReturn(JCReturn tree) {
556 buf.add(tree);
557 }
558 }.scan(speculativeTree.body);
559 res = buf.toList();
560 returnExpressions = Optional.of(res);
561 return res;
562 });
563 }
564
565 @Override
566 Type overloadCheck(ResultInfo resultInfo, DeferredAttrContext deferredAttrContext) {
567 try {
568 //compute target-type; this logic could be shared with Attr
569 TargetInfo targetInfo = attr.getTargetInfo(speculativeTree, resultInfo, argtypes());
570 Type lambdaType = targetInfo.descriptor;
571 Type currentTarget = targetInfo.target;
572 //check compatibility
573 checkLambdaCompatible(lambdaType, resultInfo);
574 return currentTarget;
575 } catch (FunctionDescriptorLookupError ex) {
576 resultInfo.checkContext.report(null, ex.getDiagnostic());
577 return null; //cannot get here
578 }
579 }
580
581 /** Check lambda against given target result */
582 private void checkLambdaCompatible(Type descriptor, ResultInfo resultInfo) {
583 CheckContext checkContext = resultInfo.checkContext;
584 ResultInfo bodyResultInfo = attr.lambdaBodyResult(speculativeTree, descriptor, resultInfo);
585 switch (speculativeTree.getBodyKind()) {
586 case EXPRESSION:
587 checkSpeculative(speculativeTree.body, speculativeTree.body.type, bodyResultInfo);
588 break;
589 case STATEMENT:
590 for (JCReturn ret : returnExpressions()) {
591 checkReturnInStatementLambda(ret, bodyResultInfo);
592 }
593 break;
594 }
595
596 attr.checkLambdaCompatible(speculativeTree, descriptor, checkContext);
597 }
598
599 /**
600 * This is an inlined version of {@link Attr#visitReturn(JCReturn)}.
601 */
602 void checkReturnInStatementLambda(JCReturn ret, ResultInfo resultInfo) {
603 if (resultInfo.pt.hasTag(VOID) && ret.expr != null) {
604 //fail - if the function type's result is void, the lambda body must be a void-compatible block.
605 resultInfo.checkContext.report(speculativeTree.pos(),
606 diags.fragment("unexpected.ret.val"));
607 } else if (!resultInfo.pt.hasTag(VOID)) {
608 if (ret.expr == null) {
609 //fail - if the function type's result is non-void, the lambda body must be a value-compatible block.
610 resultInfo.checkContext.report(speculativeTree.pos(),
611 diags.fragment("missing.ret.val"));
612 }
613 checkSpeculative(ret.expr, ret.expr.type, resultInfo);
614 }
615 }
616
617 /** Get the type associated with given return expression. */
618 Type getReturnType(JCReturn ret) {
619 if (ret.expr == null) {
620 return syms.voidType;
621 } else {
622 return ret.expr.type;
623 }
624 }
625
626 @Override
627 ArgumentType<JCLambda> dup(JCLambda tree, Env<AttrContext> env) {
628 return new ExplicitLambdaType(tree, env, speculativeTree, speculativeTypes);
629 }
630 }
631
632 /**
633 * Argument type for methods/constructors.
634 */
635 abstract class ResolvedMemberType<E extends JCExpression> extends ArgumentType<E> {
636
637 public ResolvedMemberType(JCExpression tree, Env<AttrContext> env, E speculativeMethod, Map<ResultInfo, Type> speculativeTypes) {
638 super(tree, env, speculativeMethod, speculativeTypes);
639 }
640
641 @Override
642 Type overloadCheck(ResultInfo resultInfo, DeferredAttrContext deferredAttrContext) {
643 Type mtype = methodType();
644 ResultInfo localInfo = resultInfo(resultInfo);
645 Type t;
646 if (mtype != null && mtype.hasTag(METHOD) && mtype.isPartial()) {
647 //poly invocation
648 t = ((PartiallyInferredMethodType)mtype).check(localInfo);
649 } else {
650 //standalone invocation
651 t = localInfo.check(tree.pos(), speculativeTree.type);
652 }
653 speculativeTypes.put(localInfo, t);
654 return t;
655 }
656
657 /**
658 * Get the result info to be used for performing an overload check.
659 */
660 abstract ResultInfo resultInfo(ResultInfo resultInfo);
661
662 /**
663 * Get the method type to be used for performing an overload check.
664 */
665 abstract Type methodType();
666 }
667
668 /**
669 * Argument type for methods.
670 */
671 class ResolvedMethodType extends ResolvedMemberType<JCMethodInvocation> {
672
673 public ResolvedMethodType(JCExpression tree, Env<AttrContext> env, JCMethodInvocation speculativeTree) {
674 this(tree, env, speculativeTree, new HashMap<>());
675 }
676
677 public ResolvedMethodType(JCExpression tree, Env<AttrContext> env, JCMethodInvocation speculativeTree, Map<ResultInfo, Type> speculativeTypes) {
678 super(tree, env, speculativeTree, speculativeTypes);
679 }
680
681 @Override
682 ResultInfo resultInfo(ResultInfo resultInfo) {
683 return resultInfo;
684 }
685
686 @Override
687 Type methodType() {
688 return speculativeTree.meth.type;
689 }
690
691 @Override
692 ArgumentType<JCMethodInvocation> dup(JCMethodInvocation tree, Env<AttrContext> env) {
693 return new ResolvedMethodType(tree, env, speculativeTree, speculativeTypes);
694 }
695 }
696
697 /**
698 * Argument type for constructors.
699 */
700 class ResolvedConstructorType extends ResolvedMemberType<JCNewClass> {
701
702 public ResolvedConstructorType(JCExpression tree, Env<AttrContext> env, JCNewClass speculativeTree) {
703 this(tree, env, speculativeTree, new HashMap<>());
704 }
705
706 public ResolvedConstructorType(JCExpression tree, Env<AttrContext> env, JCNewClass speculativeTree, Map<ResultInfo, Type> speculativeTypes) {
707 super(tree, env, speculativeTree, speculativeTypes);
708 }
709
710 @Override
711 ResultInfo resultInfo(ResultInfo resultInfo) {
712 return resultInfo.dup(attr.diamondContext(speculativeTree, speculativeTree.clazz.type.tsym, resultInfo.checkContext));
713 }
714
715 @Override
716 Type methodType() {
717 return (speculativeTree.constructorType != null) ?
718 speculativeTree.constructorType.baseType() : syms.errType;
719 }
720
721 @Override
722 ArgumentType<JCNewClass> dup(JCNewClass tree, Env<AttrContext> env) {
723 return new ResolvedConstructorType(tree, env, speculativeTree, speculativeTypes);
724 }
725 }
726
727 /**
728 * An instance of this class represents a unique position in a compilation unit. A unique
729 * position is made up of (i) a unique position in a source file (char offset) and (ii)
730 * a source file info.
731 */
732 class UniquePos {
733
734 /** Char offset. */
735 int pos;
736
737 /** Source info. */
738 DiagnosticSource source;
739
740 UniquePos(JCTree tree) {
741 this.pos = tree.pos;
742 this.source = log.currentSource();
743 }
744
745 @Override
746 public int hashCode() {
747 return pos << 16 + source.hashCode();
748 }
749
750 @Override
751 public boolean equals(Object obj) {
752 if (obj instanceof UniquePos) {
753 UniquePos that = (UniquePos)obj;
754 return pos == that.pos && source == that.source;
755 } else {
756 return false;
757 }
758 }
759
760 @Override
761 public String toString() {
762 return source.getFile().getName() + " @ " + source.getLineNumber(pos);
763 }
764 }
765 }