1 /*
2 * Copyright (c) 2003, 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.code;
27
28 import java.lang.ref.SoftReference;
29 import java.util.HashSet;
30 import java.util.HashMap;
31 import java.util.Locale;
32 import java.util.Map;
33 import java.util.Optional;
34 import java.util.Set;
35 import java.util.WeakHashMap;
36 import java.util.function.BiPredicate;
37 import java.util.function.Function;
38 import java.util.function.Predicate;
39 import java.util.stream.Collector;
40
41 import javax.tools.JavaFileObject;
42
43 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
44 import com.sun.tools.javac.code.Lint.LintCategory;
45 import com.sun.tools.javac.code.Source.Feature;
46 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
47 import com.sun.tools.javac.code.TypeMetadata.Entry.Kind;
48 import com.sun.tools.javac.comp.AttrContext;
49 import com.sun.tools.javac.comp.Check;
50 import com.sun.tools.javac.comp.Enter;
51 import com.sun.tools.javac.comp.Env;
52 import com.sun.tools.javac.comp.LambdaToMethod;
53 import com.sun.tools.javac.jvm.ClassFile;
54 import com.sun.tools.javac.util.*;
55
56 import static com.sun.tools.javac.code.BoundKind.*;
57 import static com.sun.tools.javac.code.Flags.*;
58 import static com.sun.tools.javac.code.Kinds.Kind.*;
59 import static com.sun.tools.javac.code.Scope.*;
60 import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
61 import static com.sun.tools.javac.code.Symbol.*;
62 import static com.sun.tools.javac.code.Type.*;
63 import static com.sun.tools.javac.code.TypeTag.*;
64 import static com.sun.tools.javac.jvm.ClassFile.externalize;
65 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
66
67 /**
68 * Utility class containing various operations on types.
69 *
70 * <p>Unless other names are more illustrative, the following naming
71 * conventions should be observed in this file:
72 *
73 * <dl>
74 * <dt>t</dt>
75 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
76 * <dt>s</dt>
77 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
78 * <dt>ts</dt>
79 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
80 * <dt>ss</dt>
81 * <dd>A second list of types should be named ss.</dd>
82 * </dl>
83 *
84 * <p><b>This is NOT part of any supported API.
85 * If you write code that depends on this, you do so at your own risk.
86 * This code and its internal interfaces are subject to change or
87 * deletion without notice.</b>
88 */
89 public class Types {
90 protected static final Context.Key<Types> typesKey = new Context.Key<>();
91
92 final Symtab syms;
93 final JavacMessages messages;
94 final Names names;
95 final Check chk;
96 final Enter enter;
97 JCDiagnostic.Factory diags;
98 List<Warner> warnStack = List.nil();
99 final Name capturedName;
100
101 public final Warner noWarnings;
102
103 // <editor-fold defaultstate="collapsed" desc="Instantiating">
104 public static Types instance(Context context) {
105 Types instance = context.get(typesKey);
106 if (instance == null)
107 instance = new Types(context);
108 return instance;
109 }
110
111 protected Types(Context context) {
112 context.put(typesKey, this);
113 syms = Symtab.instance(context);
114 names = Names.instance(context);
115 Source source = Source.instance(context);
116 chk = Check.instance(context);
117 enter = Enter.instance(context);
118 capturedName = names.fromString("<captured wildcard>");
119 messages = JavacMessages.instance(context);
120 diags = JCDiagnostic.Factory.instance(context);
121 noWarnings = new Warner(null);
122 qualifiedSymbolCache = new HashMap<>();
123 }
124 // </editor-fold>
125
126 // <editor-fold defaultstate="collapsed" desc="bounds">
127 /**
128 * Get a wildcard's upper bound, returning non-wildcards unchanged.
129 * @param t a type argument, either a wildcard or a type
130 */
131 public Type wildUpperBound(Type t) {
132 if (t.hasTag(WILDCARD)) {
133 WildcardType w = (WildcardType) t;
134 if (w.isSuperBound())
135 return w.bound == null ? syms.objectType : w.bound.getUpperBound();
136 else
137 return wildUpperBound(w.type);
138 }
139 else return t;
140 }
141
142 /**
143 * Get a capture variable's upper bound, returning other types unchanged.
144 * @param t a type
145 */
146 public Type cvarUpperBound(Type t) {
147 if (t.hasTag(TYPEVAR)) {
148 TypeVar v = (TypeVar) t;
149 return v.isCaptured() ? cvarUpperBound(v.getUpperBound()) : v;
150 }
151 else return t;
152 }
153
154 /**
155 * Get a wildcard's lower bound, returning non-wildcards unchanged.
156 * @param t a type argument, either a wildcard or a type
157 */
158 public Type wildLowerBound(Type t) {
159 if (t.hasTag(WILDCARD)) {
160 WildcardType w = (WildcardType) t;
161 return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type);
162 }
163 else return t;
164 }
165
166 /**
167 * Get a capture variable's lower bound, returning other types unchanged.
168 * @param t a type
169 */
170 public Type cvarLowerBound(Type t) {
171 if (t.hasTag(TYPEVAR) && ((TypeVar) t).isCaptured()) {
172 return cvarLowerBound(t.getLowerBound());
173 }
174 else return t;
175 }
176
177 /**
178 * Recursively skip type-variables until a class/array type is found; capture conversion is then
179 * (optionally) applied to the resulting type. This is useful for i.e. computing a site that is
180 * suitable for a method lookup.
181 */
182 public Type skipTypeVars(Type site, boolean capture) {
183 while (site.hasTag(TYPEVAR)) {
184 site = site.getUpperBound();
185 }
186 return capture ? capture(site) : site;
187 }
188 // </editor-fold>
189
190 // <editor-fold defaultstate="collapsed" desc="projections">
191
192 /**
193 * A projection kind. See {@link TypeProjection}
194 */
195 enum ProjectionKind {
196 UPWARDS() {
197 @Override
198 ProjectionKind complement() {
199 return DOWNWARDS;
200 }
201 },
202 DOWNWARDS() {
203 @Override
204 ProjectionKind complement() {
205 return UPWARDS;
206 }
207 };
208
209 abstract ProjectionKind complement();
210 }
211
212 /**
213 * This visitor performs upwards and downwards projections on types.
214 *
215 * A projection is defined as a function that takes a type T, a set of type variables V and that
216 * produces another type S.
217 *
218 * An upwards projection maps a type T into a type S such that (i) T has no variables in V,
219 * and (ii) S is an upper bound of T.
220 *
221 * A downwards projection maps a type T into a type S such that (i) T has no variables in V,
222 * and (ii) S is a lower bound of T.
223 *
224 * Note that projections are only allowed to touch variables in V. Therefore, it is possible for
225 * a projection to leave its input type unchanged if it does not contain any variables in V.
226 *
227 * Moreover, note that while an upwards projection is always defined (every type as an upper bound),
228 * a downwards projection is not always defined.
229 *
230 * Examples:
231 *
232 * {@code upwards(List<#CAP1>, [#CAP1]) = List<? extends String>, where #CAP1 <: String }
233 * {@code downwards(List<#CAP2>, [#CAP2]) = List<? super String>, where #CAP2 :> String }
234 * {@code upwards(List<#CAP1>, [#CAP2]) = List<#CAP1> }
235 * {@code downwards(List<#CAP1>, [#CAP1]) = not defined }
236 */
237 class TypeProjection extends TypeMapping<ProjectionKind> {
238
239 List<Type> vars;
240 Set<Type> seen = new HashSet<>();
241
242 public TypeProjection(List<Type> vars) {
243 this.vars = vars;
244 }
245
246 @Override
247 public Type visitClassType(ClassType t, ProjectionKind pkind) {
248 if (t.isCompound()) {
249 List<Type> components = directSupertypes(t);
250 List<Type> components1 = components.map(c -> c.map(this, pkind));
251 if (components == components1) return t;
252 else return makeIntersectionType(components1);
253 } else {
254 Type outer = t.getEnclosingType();
255 Type outer1 = visit(outer, pkind);
256 List<Type> typarams = t.getTypeArguments();
257 List<Type> formals = t.tsym.type.getTypeArguments();
258 ListBuffer<Type> typarams1 = new ListBuffer<>();
259 boolean changed = false;
260 for (Type actual : typarams) {
261 Type t2 = mapTypeArgument(t, formals.head.getUpperBound(), actual, pkind);
262 if (t2.hasTag(BOT)) {
263 //not defined
264 return syms.botType;
265 }
266 typarams1.add(t2);
267 changed |= actual != t2;
268 formals = formals.tail;
269 }
270 if (outer1 == outer && !changed) return t;
271 else return new ClassType(outer1, typarams1.toList(), t.tsym, t.getMetadata()) {
272 @Override
273 protected boolean needsStripping() {
274 return true;
275 }
276 };
277 }
278 }
279
280 @Override
281 public Type visitArrayType(ArrayType t, ProjectionKind s) {
282 Type elemtype = t.elemtype;
283 Type elemtype1 = visit(elemtype, s);
284 if (elemtype1 == elemtype) {
285 return t;
286 } else if (elemtype1.hasTag(BOT)) {
287 //undefined
288 return syms.botType;
289 } else {
290 return new ArrayType(elemtype1, t.tsym, t.metadata) {
291 @Override
292 protected boolean needsStripping() {
293 return true;
294 }
295 };
296 }
297 }
298
299 @Override
300 public Type visitTypeVar(TypeVar t, ProjectionKind pkind) {
301 if (vars.contains(t)) {
302 if (seen.add(t)) {
303 try {
304 final Type bound;
305 switch (pkind) {
306 case UPWARDS:
307 bound = t.getUpperBound();
308 break;
309 case DOWNWARDS:
310 bound = (t.getLowerBound() == null) ?
311 syms.botType :
312 t.getLowerBound();
313 break;
314 default:
315 Assert.error();
316 return null;
317 }
318 return bound.map(this, pkind);
319 } finally {
320 seen.remove(t);
321 }
322 } else {
323 //cycle
324 return pkind == ProjectionKind.UPWARDS ?
325 syms.objectType : syms.botType;
326 }
327 } else {
328 return t;
329 }
330 }
331
332 private Type mapTypeArgument(Type site, Type declaredBound, Type t, ProjectionKind pkind) {
333 return t.containsAny(vars) ?
334 t.map(new TypeArgumentProjection(site, declaredBound), pkind) :
335 t;
336 }
337
338 class TypeArgumentProjection extends TypeMapping<ProjectionKind> {
339
340 Type site;
341 Type declaredBound;
342
343 TypeArgumentProjection(Type site, Type declaredBound) {
344 this.site = site;
345 this.declaredBound = declaredBound;
346 }
347
348 @Override
349 public Type visitType(Type t, ProjectionKind pkind) {
350 //type argument is some type containing restricted vars
351 if (pkind == ProjectionKind.DOWNWARDS) {
352 //not defined
353 return syms.botType;
354 }
355 Type upper = t.map(TypeProjection.this, ProjectionKind.UPWARDS);
356 Type lower = t.map(TypeProjection.this, ProjectionKind.DOWNWARDS);
357 List<Type> formals = site.tsym.type.getTypeArguments();
358 BoundKind bk;
359 Type bound;
360 if (!isSameType(upper, syms.objectType) &&
361 (declaredBound.containsAny(formals) ||
362 !isSubtype(declaredBound, upper))) {
363 bound = upper;
364 bk = EXTENDS;
365 } else if (!lower.hasTag(BOT)) {
366 bound = lower;
367 bk = SUPER;
368 } else {
369 bound = syms.objectType;
370 bk = UNBOUND;
371 }
372 return makeWildcard(bound, bk);
373 }
374
375 @Override
376 public Type visitWildcardType(WildcardType wt, ProjectionKind pkind) {
377 //type argument is some wildcard whose bound contains restricted vars
378 Type bound = syms.botType;
379 BoundKind bk = wt.kind;
380 switch (wt.kind) {
381 case EXTENDS:
382 bound = wt.type.map(TypeProjection.this, pkind);
383 if (bound.hasTag(BOT)) {
384 return syms.botType;
385 }
386 break;
387 case SUPER:
388 bound = wt.type.map(TypeProjection.this, pkind.complement());
389 if (bound.hasTag(BOT)) {
390 bound = syms.objectType;
391 bk = UNBOUND;
392 }
393 break;
394 }
395 return makeWildcard(bound, bk);
396 }
397
398 private Type makeWildcard(Type bound, BoundKind bk) {
399 return new WildcardType(bound, bk, syms.boundClass) {
400 @Override
401 protected boolean needsStripping() {
402 return true;
403 }
404 };
405 }
406 }
407 }
408
409 /**
410 * Computes an upward projection of given type, and vars. See {@link TypeProjection}.
411 *
412 * @param t the type to be projected
413 * @param vars the set of type variables to be mapped
414 * @return the type obtained as result of the projection
415 */
416 public Type upward(Type t, List<Type> vars) {
417 return t.map(new TypeProjection(vars), ProjectionKind.UPWARDS);
418 }
419
420 /**
421 * Computes the set of captured variables mentioned in a given type. See {@link CaptureScanner}.
422 * This routine is typically used to computed the input set of variables to be used during
423 * an upwards projection (see {@link Types#upward(Type, List)}).
424 *
425 * @param t the type where occurrences of captured variables have to be found
426 * @return the set of captured variables found in t
427 */
428 public List<Type> captures(Type t) {
429 CaptureScanner cs = new CaptureScanner();
430 Set<Type> captures = new HashSet<>();
431 cs.visit(t, captures);
432 return List.from(captures);
433 }
434
435 /**
436 * This visitor scans a type recursively looking for occurrences of captured type variables.
437 */
438 class CaptureScanner extends SimpleVisitor<Void, Set<Type>> {
439
440 @Override
441 public Void visitType(Type t, Set<Type> types) {
442 return null;
443 }
444
445 @Override
446 public Void visitClassType(ClassType t, Set<Type> seen) {
447 if (t.isCompound()) {
448 directSupertypes(t).forEach(s -> visit(s, seen));
449 } else {
450 t.allparams().forEach(ta -> visit(ta, seen));
451 }
452 return null;
453 }
454
455 @Override
456 public Void visitArrayType(ArrayType t, Set<Type> seen) {
457 return visit(t.elemtype, seen);
458 }
459
460 @Override
461 public Void visitWildcardType(WildcardType t, Set<Type> seen) {
462 visit(t.type, seen);
463 return null;
464 }
465
466 @Override
467 public Void visitTypeVar(TypeVar t, Set<Type> seen) {
468 if ((t.tsym.flags() & Flags.SYNTHETIC) != 0 && seen.add(t)) {
469 visit(t.getUpperBound(), seen);
470 }
471 return null;
472 }
473
474 @Override
475 public Void visitCapturedType(CapturedType t, Set<Type> seen) {
476 if (seen.add(t)) {
477 visit(t.getUpperBound(), seen);
478 visit(t.getLowerBound(), seen);
479 }
480 return null;
481 }
482 }
483
484 // </editor-fold>
485
486 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
487 /**
488 * Checks that all the arguments to a class are unbounded
489 * wildcards or something else that doesn't make any restrictions
490 * on the arguments. If a class isUnbounded, a raw super- or
491 * subclass can be cast to it without a warning.
492 * @param t a type
493 * @return true iff the given type is unbounded or raw
494 */
495 public boolean isUnbounded(Type t) {
496 return isUnbounded.visit(t);
497 }
498 // where
499 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
500
501 public Boolean visitType(Type t, Void ignored) {
502 return true;
503 }
504
505 @Override
506 public Boolean visitClassType(ClassType t, Void ignored) {
507 List<Type> parms = t.tsym.type.allparams();
508 List<Type> args = t.allparams();
509 while (parms.nonEmpty()) {
510 WildcardType unb = new WildcardType(syms.objectType,
511 BoundKind.UNBOUND,
512 syms.boundClass,
513 (TypeVar)parms.head);
514 if (!containsType(args.head, unb))
515 return false;
516 parms = parms.tail;
517 args = args.tail;
518 }
519 return true;
520 }
521 };
522 // </editor-fold>
523
524 // <editor-fold defaultstate="collapsed" desc="asSub">
525 /**
526 * Return the least specific subtype of t that starts with symbol
527 * sym. If none exists, return null. The least specific subtype
528 * is determined as follows:
529 *
530 * <p>If there is exactly one parameterized instance of sym that is a
531 * subtype of t, that parameterized instance is returned.<br>
532 * Otherwise, if the plain type or raw type `sym' is a subtype of
533 * type t, the type `sym' itself is returned. Otherwise, null is
534 * returned.
535 */
536 public Type asSub(Type t, Symbol sym) {
537 return asSub.visit(t, sym);
538 }
539 // where
540 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
541
542 public Type visitType(Type t, Symbol sym) {
543 return null;
544 }
545
546 @Override
547 public Type visitClassType(ClassType t, Symbol sym) {
548 if (t.tsym == sym)
549 return t;
550 Type base = asSuper(sym.type, t.tsym);
551 if (base == null)
552 return null;
553 ListBuffer<Type> from = new ListBuffer<>();
554 ListBuffer<Type> to = new ListBuffer<>();
555 try {
556 adapt(base, t, from, to);
557 } catch (AdaptFailure ex) {
558 return null;
559 }
560 Type res = subst(sym.type, from.toList(), to.toList());
561 if (!isSubtype(res, t))
562 return null;
563 ListBuffer<Type> openVars = new ListBuffer<>();
564 for (List<Type> l = sym.type.allparams();
565 l.nonEmpty(); l = l.tail)
566 if (res.contains(l.head) && !t.contains(l.head))
567 openVars.append(l.head);
568 if (openVars.nonEmpty()) {
569 if (t.isRaw()) {
570 // The subtype of a raw type is raw
571 res = erasure(res);
572 } else {
573 // Unbound type arguments default to ?
574 List<Type> opens = openVars.toList();
575 ListBuffer<Type> qs = new ListBuffer<>();
576 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
577 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND,
578 syms.boundClass, (TypeVar) iter.head));
579 }
580 res = subst(res, opens, qs.toList());
581 }
582 }
583 return res;
584 }
585
586 @Override
587 public Type visitErrorType(ErrorType t, Symbol sym) {
588 return t;
589 }
590 };
591 // </editor-fold>
592
593 // <editor-fold defaultstate="collapsed" desc="isConvertible">
594 /**
595 * Is t a subtype of or convertible via boxing/unboxing
596 * conversion to s?
597 */
598 public boolean isConvertible(Type t, Type s, Warner warn) {
599 if (t.hasTag(ERROR)) {
600 return true;
601 }
602 boolean tPrimitive = t.isPrimitive();
603 boolean sPrimitive = s.isPrimitive();
604 if (tPrimitive == sPrimitive) {
605 return isSubtypeUnchecked(t, s, warn);
606 }
607 boolean tUndet = t.hasTag(UNDETVAR);
608 boolean sUndet = s.hasTag(UNDETVAR);
609
610 if (tUndet || sUndet) {
611 return tUndet ?
612 isSubtype(t, boxedTypeOrType(s)) :
613 isSubtype(boxedTypeOrType(t), s);
614 }
615
616 return tPrimitive
617 ? isSubtype(boxedClass(t).type, s)
618 : isSubtype(unboxedType(t), s);
619 }
620
621 /**
622 * Is t a subtype of or convertible via boxing/unboxing
623 * conversions to s?
624 */
625 public boolean isConvertible(Type t, Type s) {
626 return isConvertible(t, s, noWarnings);
627 }
628 // </editor-fold>
629
630 // <editor-fold defaultstate="collapsed" desc="findSam">
631
632 /**
633 * Exception used to report a function descriptor lookup failure. The exception
634 * wraps a diagnostic that can be used to generate more details error
635 * messages.
636 */
637 public static class FunctionDescriptorLookupError extends RuntimeException {
638 private static final long serialVersionUID = 0;
639
640 transient JCDiagnostic diagnostic;
641
642 FunctionDescriptorLookupError() {
643 this.diagnostic = null;
644 }
645
646 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
647 this.diagnostic = diag;
648 return this;
649 }
650
651 public JCDiagnostic getDiagnostic() {
652 return diagnostic;
653 }
654
655 @Override
656 public Throwable fillInStackTrace() {
657 // This is an internal exception; the stack trace is irrelevant.
658 return this;
659 }
660 }
661
662 /**
663 * A cache that keeps track of function descriptors associated with given
664 * functional interfaces.
665 */
666 class DescriptorCache {
667
668 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<>();
669
670 class FunctionDescriptor {
671 Symbol descSym;
672
673 FunctionDescriptor(Symbol descSym) {
674 this.descSym = descSym;
675 }
676
677 public Symbol getSymbol() {
678 return descSym;
679 }
680
681 public Type getType(Type site) {
682 site = removeWildcards(site);
683 if (site.isIntersection()) {
684 IntersectionClassType ict = (IntersectionClassType)site;
685 for (Type component : ict.getExplicitComponents()) {
686 if (!chk.checkValidGenericType(component)) {
687 //if the inferred functional interface type is not well-formed,
688 //or if it's not a subtype of the original target, issue an error
689 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
690 }
691 }
692 } else {
693 if (!chk.checkValidGenericType(site)) {
694 //if the inferred functional interface type is not well-formed,
695 //or if it's not a subtype of the original target, issue an error
696 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
697 }
698 }
699 return memberType(site, descSym);
700 }
701 }
702
703 class Entry {
704 final FunctionDescriptor cachedDescRes;
705 final int prevMark;
706
707 public Entry(FunctionDescriptor cachedDescRes,
708 int prevMark) {
709 this.cachedDescRes = cachedDescRes;
710 this.prevMark = prevMark;
711 }
712
713 boolean matches(int mark) {
714 return this.prevMark == mark;
715 }
716 }
717
718 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
719 Entry e = _map.get(origin);
720 CompoundScope members = membersClosure(origin.type, false);
721 if (e == null ||
722 !e.matches(members.getMark())) {
723 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
724 _map.put(origin, new Entry(descRes, members.getMark()));
725 return descRes;
726 }
727 else {
728 return e.cachedDescRes;
729 }
730 }
731
732 /**
733 * Compute the function descriptor associated with a given functional interface
734 */
735 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin,
736 CompoundScope membersCache) throws FunctionDescriptorLookupError {
737 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0 || origin.isSealed()) {
738 //t must be an interface
739 throw failure("not.a.functional.intf", origin);
740 }
741
742 final ListBuffer<Symbol> abstracts = new ListBuffer<>();
743 for (Symbol sym : membersCache.getSymbols(new DescriptorFilter(origin))) {
744 Type mtype = memberType(origin.type, sym);
745 if (abstracts.isEmpty()) {
746 abstracts.append(sym);
747 } else if ((sym.name == abstracts.first().name &&
748 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
749 if (!abstracts.stream().filter(msym -> msym.owner.isSubClass(sym.enclClass(), Types.this))
750 .map(msym -> memberType(origin.type, msym))
751 .anyMatch(abstractMType -> isSubSignature(abstractMType, mtype))) {
752 abstracts.append(sym);
753 }
754 } else {
755 //the target method(s) should be the only abstract members of t
756 throw failure("not.a.functional.intf.1", origin,
757 diags.fragment(Fragments.IncompatibleAbstracts(Kinds.kindName(origin), origin)));
758 }
759 }
760 if (abstracts.isEmpty()) {
761 //t must define a suitable non-generic method
762 throw failure("not.a.functional.intf.1", origin,
763 diags.fragment(Fragments.NoAbstracts(Kinds.kindName(origin), origin)));
764 } else if (abstracts.size() == 1) {
765 return new FunctionDescriptor(abstracts.first());
766 } else { // size > 1
767 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
768 if (descRes == null) {
769 //we can get here if the functional interface is ill-formed
770 ListBuffer<JCDiagnostic> descriptors = new ListBuffer<>();
771 for (Symbol desc : abstracts) {
772 String key = desc.type.getThrownTypes().nonEmpty() ?
773 "descriptor.throws" : "descriptor";
774 descriptors.append(diags.fragment(key, desc.name,
775 desc.type.getParameterTypes(),
776 desc.type.getReturnType(),
777 desc.type.getThrownTypes()));
778 }
779 JCDiagnostic msg =
780 diags.fragment(Fragments.IncompatibleDescsInFunctionalIntf(Kinds.kindName(origin),
781 origin));
782 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
783 new JCDiagnostic.MultilineDiagnostic(msg, descriptors.toList());
784 throw failure(incompatibleDescriptors);
785 }
786 return descRes;
787 }
788 }
789
790 /**
791 * Compute a synthetic type for the target descriptor given a list
792 * of override-equivalent methods in the functional interface type.
793 * The resulting method type is a method type that is override-equivalent
794 * and return-type substitutable with each method in the original list.
795 */
796 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
797 return mergeAbstracts(methodSyms, origin.type, false)
798 .map(bestSoFar -> new FunctionDescriptor(bestSoFar.baseSymbol()) {
799 @Override
800 public Type getType(Type origin) {
801 Type mt = memberType(origin, getSymbol());
802 return createMethodTypeWithThrown(mt, bestSoFar.type.getThrownTypes());
803 }
804 }).orElse(null);
805 }
806
807 FunctionDescriptorLookupError failure(String msg, Object... args) {
808 return failure(diags.fragment(msg, args));
809 }
810
811 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
812 return new FunctionDescriptorLookupError().setMessage(diag);
813 }
814 }
815
816 private DescriptorCache descCache = new DescriptorCache();
817
818 /**
819 * Find the method descriptor associated to this class symbol - if the
820 * symbol 'origin' is not a functional interface, an exception is thrown.
821 */
822 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
823 return descCache.get(origin).getSymbol();
824 }
825
826 /**
827 * Find the type of the method descriptor associated to this class symbol -
828 * if the symbol 'origin' is not a functional interface, an exception is thrown.
829 */
830 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
831 return descCache.get(origin.tsym).getType(origin);
832 }
833
834 /**
835 * Is given type a functional interface?
836 */
837 public boolean isFunctionalInterface(TypeSymbol tsym) {
838 try {
839 findDescriptorSymbol(tsym);
840 return true;
841 } catch (FunctionDescriptorLookupError ex) {
842 return false;
843 }
844 }
845
846 public boolean isFunctionalInterface(Type site) {
847 try {
848 findDescriptorType(site);
849 return true;
850 } catch (FunctionDescriptorLookupError ex) {
851 return false;
852 }
853 }
854
855 public Type removeWildcards(Type site) {
856 if (site.getTypeArguments().stream().anyMatch(t -> t.hasTag(WILDCARD))) {
857 //compute non-wildcard parameterization - JLS 9.9
858 List<Type> actuals = site.getTypeArguments();
859 List<Type> formals = site.tsym.type.getTypeArguments();
860 ListBuffer<Type> targs = new ListBuffer<>();
861 for (Type formal : formals) {
862 Type actual = actuals.head;
863 Type bound = formal.getUpperBound();
864 if (actuals.head.hasTag(WILDCARD)) {
865 WildcardType wt = (WildcardType)actual;
866 //check that bound does not contain other formals
867 if (bound.containsAny(formals)) {
868 targs.add(wt.type);
869 } else {
870 //compute new type-argument based on declared bound and wildcard bound
871 switch (wt.kind) {
872 case UNBOUND:
873 targs.add(bound);
874 break;
875 case EXTENDS:
876 targs.add(glb(bound, wt.type));
877 break;
878 case SUPER:
879 targs.add(wt.type);
880 break;
881 default:
882 Assert.error("Cannot get here!");
883 }
884 }
885 } else {
886 //not a wildcard - the new type argument remains unchanged
887 targs.add(actual);
888 }
889 actuals = actuals.tail;
890 }
891 return subst(site.tsym.type, formals, targs.toList());
892 } else {
893 return site;
894 }
895 }
896
897 /**
898 * Create a symbol for a class that implements a given functional interface
899 * and overrides its functional descriptor. This routine is used for two
900 * main purposes: (i) checking well-formedness of a functional interface;
901 * (ii) perform functional interface bridge calculation.
902 */
903 public ClassSymbol makeFunctionalInterfaceClass(Env<AttrContext> env, Name name, Type target, long cflags) {
904 if (target == null || target == syms.unknownType) {
905 return null;
906 }
907 Symbol descSym = findDescriptorSymbol(target.tsym);
908 Type descType = findDescriptorType(target);
909 ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass());
910 csym.completer = Completer.NULL_COMPLETER;
911 csym.members_field = WriteableScope.create(csym);
912 MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym);
913 csym.members_field.enter(instDescSym);
914 Type.ClassType ctype = new Type.ClassType(Type.noType, List.nil(), csym);
915 ctype.supertype_field = syms.objectType;
916 ctype.interfaces_field = target.isIntersection() ?
917 directSupertypes(target) :
918 List.of(target);
919 csym.type = ctype;
920 csym.sourcefile = ((ClassSymbol)csym.owner).sourcefile;
921 return csym;
922 }
923
924 /**
925 * Find the minimal set of methods that are overridden by the functional
926 * descriptor in 'origin'. All returned methods are assumed to have different
927 * erased signatures.
928 */
929 public List<Symbol> functionalInterfaceBridges(TypeSymbol origin) {
930 Assert.check(isFunctionalInterface(origin));
931 Symbol descSym = findDescriptorSymbol(origin);
932 CompoundScope members = membersClosure(origin.type, false);
933 ListBuffer<Symbol> overridden = new ListBuffer<>();
934 outer: for (Symbol m2 : members.getSymbolsByName(descSym.name, bridgeFilter)) {
935 if (m2 == descSym) continue;
936 else if (descSym.overrides(m2, origin, Types.this, false)) {
937 for (Symbol m3 : overridden) {
938 if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) ||
939 (m3.overrides(m2, origin, Types.this, false) &&
940 (pendingBridges((ClassSymbol)origin, m3.enclClass()) ||
941 (((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) {
942 continue outer;
943 }
944 }
945 overridden.add(m2);
946 }
947 }
948 return overridden.toList();
949 }
950 //where
951 // Use anonymous class instead of lambda expression intentionally,
952 // because the variable `names` has modifier: final.
953 private Predicate<Symbol> bridgeFilter = new Predicate<Symbol>() {
954 public boolean test(Symbol t) {
955 return t.kind == MTH &&
956 t.name != names.init &&
957 t.name != names.clinit &&
958 (t.flags() & SYNTHETIC) == 0;
959 }
960 };
961
962 private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) {
963 //a symbol will be completed from a classfile if (a) symbol has
964 //an associated file object with CLASS kind and (b) the symbol has
965 //not been entered
966 if (origin.classfile != null &&
967 origin.classfile.getKind() == JavaFileObject.Kind.CLASS &&
968 enter.getEnv(origin) == null) {
969 return false;
970 }
971 if (origin == s) {
972 return true;
973 }
974 for (Type t : interfaces(origin.type)) {
975 if (pendingBridges((ClassSymbol)t.tsym, s)) {
976 return true;
977 }
978 }
979 return false;
980 }
981 // </editor-fold>
982
983 /**
984 * Scope filter used to skip methods that should be ignored (such as methods
985 * overridden by j.l.Object) during function interface conversion interface check
986 */
987 class DescriptorFilter implements Predicate<Symbol> {
988
989 TypeSymbol origin;
990
991 DescriptorFilter(TypeSymbol origin) {
992 this.origin = origin;
993 }
994
995 @Override
996 public boolean test(Symbol sym) {
997 return sym.kind == MTH &&
998 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
999 !overridesObjectMethod(origin, sym) &&
1000 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
1001 }
1002 }
1003
1004 // <editor-fold defaultstate="collapsed" desc="isSubtype">
1005 /**
1006 * Is t an unchecked subtype of s?
1007 */
1008 public boolean isSubtypeUnchecked(Type t, Type s) {
1009 return isSubtypeUnchecked(t, s, noWarnings);
1010 }
1011 /**
1012 * Is t an unchecked subtype of s?
1013 */
1014 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
1015 boolean result = isSubtypeUncheckedInternal(t, s, true, warn);
1016 if (result) {
1017 checkUnsafeVarargsConversion(t, s, warn);
1018 }
1019 return result;
1020 }
1021 //where
1022 private boolean isSubtypeUncheckedInternal(Type t, Type s, boolean capture, Warner warn) {
1023 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
1024 if (((ArrayType)t).elemtype.isPrimitive()) {
1025 return isSameType(elemtype(t), elemtype(s));
1026 } else {
1027 return isSubtypeUncheckedInternal(elemtype(t), elemtype(s), false, warn);
1028 }
1029 } else if (isSubtype(t, s, capture)) {
1030 return true;
1031 } else if (t.hasTag(TYPEVAR)) {
1032 return isSubtypeUncheckedInternal(t.getUpperBound(), s, false, warn);
1033 } else if (!s.isRaw()) {
1034 Type t2 = asSuper(t, s.tsym);
1035 if (t2 != null && t2.isRaw()) {
1036 if (isReifiable(s)) {
1037 warn.silentWarn(LintCategory.UNCHECKED);
1038 } else {
1039 warn.warn(LintCategory.UNCHECKED);
1040 }
1041 return true;
1042 }
1043 }
1044 return false;
1045 }
1046
1047 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
1048 if (!t.hasTag(ARRAY) || isReifiable(t)) {
1049 return;
1050 }
1051 ArrayType from = (ArrayType)t;
1052 boolean shouldWarn = false;
1053 switch (s.getTag()) {
1054 case ARRAY:
1055 ArrayType to = (ArrayType)s;
1056 shouldWarn = from.isVarargs() &&
1057 !to.isVarargs() &&
1058 !isReifiable(from);
1059 break;
1060 case CLASS:
1061 shouldWarn = from.isVarargs();
1062 break;
1063 }
1064 if (shouldWarn) {
1065 warn.warn(LintCategory.VARARGS);
1066 }
1067 }
1068
1069 /**
1070 * Is t a subtype of s?<br>
1071 * (not defined for Method and ForAll types)
1072 */
1073 public final boolean isSubtype(Type t, Type s) {
1074 return isSubtype(t, s, true);
1075 }
1076 public final boolean isSubtypeNoCapture(Type t, Type s) {
1077 return isSubtype(t, s, false);
1078 }
1079 public boolean isSubtype(Type t, Type s, boolean capture) {
1080 if (t.equalsIgnoreMetadata(s))
1081 return true;
1082 if (s.isPartial())
1083 return isSuperType(s, t);
1084
1085 if (s.isCompound()) {
1086 for (Type s2 : interfaces(s).prepend(supertype(s))) {
1087 if (!isSubtype(t, s2, capture))
1088 return false;
1089 }
1090 return true;
1091 }
1092
1093 // Generally, if 's' is a lower-bounded type variable, recur on lower bound; but
1094 // for inference variables and intersections, we need to keep 's'
1095 // (see JLS 4.10.2 for intersections and 18.2.3 for inference vars)
1096 if (!t.hasTag(UNDETVAR) && !t.isCompound()) {
1097 // TODO: JDK-8039198, bounds checking sometimes passes in a wildcard as s
1098 Type lower = cvarLowerBound(wildLowerBound(s));
1099 if (s != lower && !lower.hasTag(BOT))
1100 return isSubtype(capture ? capture(t) : t, lower, false);
1101 }
1102
1103 return isSubtype.visit(capture ? capture(t) : t, s);
1104 }
1105 // where
1106 private TypeRelation isSubtype = new TypeRelation()
1107 {
1108 @Override
1109 public Boolean visitType(Type t, Type s) {
1110 switch (t.getTag()) {
1111 case BYTE:
1112 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
1113 case CHAR:
1114 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
1115 case SHORT: case INT: case LONG:
1116 case FLOAT: case DOUBLE:
1117 return t.getTag().isSubRangeOf(s.getTag());
1118 case BOOLEAN: case VOID:
1119 return t.hasTag(s.getTag());
1120 case TYPEVAR:
1121 return isSubtypeNoCapture(t.getUpperBound(), s);
1122 case BOT:
1123 return
1124 s.hasTag(BOT) || s.hasTag(CLASS) ||
1125 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
1126 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
1127 case NONE:
1128 return false;
1129 default:
1130 throw new AssertionError("isSubtype " + t.getTag());
1131 }
1132 }
1133
1134 private Set<TypePair> cache = new HashSet<>();
1135
1136 private boolean containsTypeRecursive(Type t, Type s) {
1137 TypePair pair = new TypePair(t, s);
1138 if (cache.add(pair)) {
1139 try {
1140 return containsType(t.getTypeArguments(),
1141 s.getTypeArguments());
1142 } finally {
1143 cache.remove(pair);
1144 }
1145 } else {
1146 return containsType(t.getTypeArguments(),
1147 rewriteSupers(s).getTypeArguments());
1148 }
1149 }
1150
1151 private Type rewriteSupers(Type t) {
1152 if (!t.isParameterized())
1153 return t;
1154 ListBuffer<Type> from = new ListBuffer<>();
1155 ListBuffer<Type> to = new ListBuffer<>();
1156 adaptSelf(t, from, to);
1157 if (from.isEmpty())
1158 return t;
1159 ListBuffer<Type> rewrite = new ListBuffer<>();
1160 boolean changed = false;
1161 for (Type orig : to.toList()) {
1162 Type s = rewriteSupers(orig);
1163 if (s.isSuperBound() && !s.isExtendsBound()) {
1164 s = new WildcardType(syms.objectType,
1165 BoundKind.UNBOUND,
1166 syms.boundClass,
1167 s.getMetadata());
1168 changed = true;
1169 } else if (s != orig) {
1170 s = new WildcardType(wildUpperBound(s),
1171 BoundKind.EXTENDS,
1172 syms.boundClass,
1173 s.getMetadata());
1174 changed = true;
1175 }
1176 rewrite.append(s);
1177 }
1178 if (changed)
1179 return subst(t.tsym.type, from.toList(), rewrite.toList());
1180 else
1181 return t;
1182 }
1183
1184 @Override
1185 public Boolean visitClassType(ClassType t, Type s) {
1186 Type sup = asSuper(t, s.tsym);
1187 if (sup == null) return false;
1188 // If t is an intersection, sup might not be a class type
1189 if (!sup.hasTag(CLASS)) return isSubtypeNoCapture(sup, s);
1190 return sup.tsym == s.tsym
1191 // Check type variable containment
1192 && (!s.isParameterized() || containsTypeRecursive(s, sup))
1193 && isSubtypeNoCapture(sup.getEnclosingType(),
1194 s.getEnclosingType());
1195 }
1196
1197 @Override
1198 public Boolean visitArrayType(ArrayType t, Type s) {
1199 if (s.hasTag(ARRAY)) {
1200 if (t.elemtype.isPrimitive())
1201 return isSameType(t.elemtype, elemtype(s));
1202 else
1203 return isSubtypeNoCapture(t.elemtype, elemtype(s));
1204 }
1205
1206 if (s.hasTag(CLASS)) {
1207 Name sname = s.tsym.getQualifiedName();
1208 return sname == names.java_lang_Object
1209 || sname == names.java_lang_Cloneable
1210 || sname == names.java_io_Serializable;
1211 }
1212
1213 return false;
1214 }
1215
1216 @Override
1217 public Boolean visitUndetVar(UndetVar t, Type s) {
1218 //todo: test against origin needed? or replace with substitution?
1219 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
1220 return true;
1221 } else if (s.hasTag(BOT)) {
1222 //if 's' is 'null' there's no instantiated type U for which
1223 //U <: s (but 'null' itself, which is not a valid type)
1224 return false;
1225 }
1226
1227 t.addBound(InferenceBound.UPPER, s, Types.this);
1228 return true;
1229 }
1230
1231 @Override
1232 public Boolean visitErrorType(ErrorType t, Type s) {
1233 return true;
1234 }
1235 };
1236
1237 /**
1238 * Is t a subtype of every type in given list `ts'?<br>
1239 * (not defined for Method and ForAll types)<br>
1240 * Allows unchecked conversions.
1241 */
1242 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
1243 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
1244 if (!isSubtypeUnchecked(t, l.head, warn))
1245 return false;
1246 return true;
1247 }
1248
1249 /**
1250 * Are corresponding elements of ts subtypes of ss? If lists are
1251 * of different length, return false.
1252 */
1253 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
1254 while (ts.tail != null && ss.tail != null
1255 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1256 isSubtype(ts.head, ss.head)) {
1257 ts = ts.tail;
1258 ss = ss.tail;
1259 }
1260 return ts.tail == null && ss.tail == null;
1261 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1262 }
1263
1264 /**
1265 * Are corresponding elements of ts subtypes of ss, allowing
1266 * unchecked conversions? If lists are of different length,
1267 * return false.
1268 **/
1269 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
1270 while (ts.tail != null && ss.tail != null
1271 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1272 isSubtypeUnchecked(ts.head, ss.head, warn)) {
1273 ts = ts.tail;
1274 ss = ss.tail;
1275 }
1276 return ts.tail == null && ss.tail == null;
1277 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1278 }
1279 // </editor-fold>
1280
1281 // <editor-fold defaultstate="collapsed" desc="isSuperType">
1282 /**
1283 * Is t a supertype of s?
1284 */
1285 public boolean isSuperType(Type t, Type s) {
1286 switch (t.getTag()) {
1287 case ERROR:
1288 return true;
1289 case UNDETVAR: {
1290 UndetVar undet = (UndetVar)t;
1291 if (t == s ||
1292 undet.qtype == s ||
1293 s.hasTag(ERROR) ||
1294 s.hasTag(BOT)) {
1295 return true;
1296 }
1297 undet.addBound(InferenceBound.LOWER, s, this);
1298 return true;
1299 }
1300 default:
1301 return isSubtype(s, t);
1302 }
1303 }
1304 // </editor-fold>
1305
1306 // <editor-fold defaultstate="collapsed" desc="isSameType">
1307 /**
1308 * Are corresponding elements of the lists the same type? If
1309 * lists are of different length, return false.
1310 */
1311 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
1312 while (ts.tail != null && ss.tail != null
1313 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1314 isSameType(ts.head, ss.head)) {
1315 ts = ts.tail;
1316 ss = ss.tail;
1317 }
1318 return ts.tail == null && ss.tail == null;
1319 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1320 }
1321
1322 /**
1323 * A polymorphic signature method (JLS 15.12.3) is a method that
1324 * (i) is declared in the java.lang.invoke.MethodHandle/VarHandle classes;
1325 * (ii) takes a single variable arity parameter;
1326 * (iii) whose declared type is Object[];
1327 * (iv) has any return type, Object signifying a polymorphic return type; and
1328 * (v) is native.
1329 */
1330 public boolean isSignaturePolymorphic(MethodSymbol msym) {
1331 List<Type> argtypes = msym.type.getParameterTypes();
1332 return (msym.flags_field & NATIVE) != 0 &&
1333 (msym.owner == syms.methodHandleType.tsym || msym.owner == syms.varHandleType.tsym) &&
1334 argtypes.length() == 1 &&
1335 argtypes.head.hasTag(TypeTag.ARRAY) &&
1336 ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym;
1337 }
1338
1339 /**
1340 * Is t the same type as s?
1341 */
1342 public boolean isSameType(Type t, Type s) {
1343 return isSameTypeVisitor.visit(t, s);
1344 }
1345 // where
1346
1347 /**
1348 * Type-equality relation - type variables are considered
1349 * equals if they share the same object identity.
1350 */
1351 TypeRelation isSameTypeVisitor = new TypeRelation() {
1352
1353 public Boolean visitType(Type t, Type s) {
1354 if (t.equalsIgnoreMetadata(s))
1355 return true;
1356
1357 if (s.isPartial())
1358 return visit(s, t);
1359
1360 switch (t.getTag()) {
1361 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1362 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
1363 return t.hasTag(s.getTag());
1364 case TYPEVAR: {
1365 if (s.hasTag(TYPEVAR)) {
1366 //type-substitution does not preserve type-var types
1367 //check that type var symbols and bounds are indeed the same
1368 return t == s;
1369 }
1370 else {
1371 //special case for s == ? super X, where upper(s) = u
1372 //check that u == t, where u has been set by Type.withTypeVar
1373 return s.isSuperBound() &&
1374 !s.isExtendsBound() &&
1375 visit(t, wildUpperBound(s));
1376 }
1377 }
1378 default:
1379 throw new AssertionError("isSameType " + t.getTag());
1380 }
1381 }
1382
1383 @Override
1384 public Boolean visitWildcardType(WildcardType t, Type s) {
1385 if (!s.hasTag(WILDCARD)) {
1386 return false;
1387 } else {
1388 WildcardType t2 = (WildcardType)s;
1389 return (t.kind == t2.kind || (t.isExtendsBound() && s.isExtendsBound())) &&
1390 isSameType(t.type, t2.type);
1391 }
1392 }
1393
1394 @Override
1395 public Boolean visitClassType(ClassType t, Type s) {
1396 if (t == s)
1397 return true;
1398
1399 if (s.isPartial())
1400 return visit(s, t);
1401
1402 if (s.isSuperBound() && !s.isExtendsBound())
1403 return visit(t, wildUpperBound(s)) && visit(t, wildLowerBound(s));
1404
1405 if (t.isCompound() && s.isCompound()) {
1406 if (!visit(supertype(t), supertype(s)))
1407 return false;
1408
1409 Map<Symbol,Type> tMap = new HashMap<>();
1410 for (Type ti : interfaces(t)) {
1411 if (tMap.containsKey(ti)) {
1412 throw new AssertionError("Malformed intersection");
1413 }
1414 tMap.put(ti.tsym, ti);
1415 }
1416 for (Type si : interfaces(s)) {
1417 if (!tMap.containsKey(si.tsym))
1418 return false;
1419 Type ti = tMap.remove(si.tsym);
1420 if (!visit(ti, si))
1421 return false;
1422 }
1423 return tMap.isEmpty();
1424 }
1425 return t.tsym == s.tsym
1426 && visit(t.getEnclosingType(), s.getEnclosingType())
1427 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
1428 }
1429
1430 @Override
1431 public Boolean visitArrayType(ArrayType t, Type s) {
1432 if (t == s)
1433 return true;
1434
1435 if (s.isPartial())
1436 return visit(s, t);
1437
1438 return s.hasTag(ARRAY)
1439 && containsTypeEquivalent(t.elemtype, elemtype(s));
1440 }
1441
1442 @Override
1443 public Boolean visitMethodType(MethodType t, Type s) {
1444 // isSameType for methods does not take thrown
1445 // exceptions into account!
1446 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
1447 }
1448
1449 @Override
1450 public Boolean visitPackageType(PackageType t, Type s) {
1451 return t == s;
1452 }
1453
1454 @Override
1455 public Boolean visitForAll(ForAll t, Type s) {
1456 if (!s.hasTag(FORALL)) {
1457 return false;
1458 }
1459
1460 ForAll forAll = (ForAll)s;
1461 return hasSameBounds(t, forAll)
1462 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1463 }
1464
1465 @Override
1466 public Boolean visitUndetVar(UndetVar t, Type s) {
1467 if (s.hasTag(WILDCARD)) {
1468 // FIXME, this might be leftovers from before capture conversion
1469 return false;
1470 }
1471
1472 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
1473 return true;
1474 }
1475
1476 t.addBound(InferenceBound.EQ, s, Types.this);
1477
1478 return true;
1479 }
1480
1481 @Override
1482 public Boolean visitErrorType(ErrorType t, Type s) {
1483 return true;
1484 }
1485 };
1486
1487 // </editor-fold>
1488
1489 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1490 public boolean containedBy(Type t, Type s) {
1491 switch (t.getTag()) {
1492 case UNDETVAR:
1493 if (s.hasTag(WILDCARD)) {
1494 UndetVar undetvar = (UndetVar)t;
1495 WildcardType wt = (WildcardType)s;
1496 switch(wt.kind) {
1497 case UNBOUND:
1498 break;
1499 case EXTENDS: {
1500 Type bound = wildUpperBound(s);
1501 undetvar.addBound(InferenceBound.UPPER, bound, this);
1502 break;
1503 }
1504 case SUPER: {
1505 Type bound = wildLowerBound(s);
1506 undetvar.addBound(InferenceBound.LOWER, bound, this);
1507 break;
1508 }
1509 }
1510 return true;
1511 } else {
1512 return isSameType(t, s);
1513 }
1514 case ERROR:
1515 return true;
1516 default:
1517 return containsType(s, t);
1518 }
1519 }
1520
1521 boolean containsType(List<Type> ts, List<Type> ss) {
1522 while (ts.nonEmpty() && ss.nonEmpty()
1523 && containsType(ts.head, ss.head)) {
1524 ts = ts.tail;
1525 ss = ss.tail;
1526 }
1527 return ts.isEmpty() && ss.isEmpty();
1528 }
1529
1530 /**
1531 * Check if t contains s.
1532 *
1533 * <p>T contains S if:
1534 *
1535 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1536 *
1537 * <p>This relation is only used by ClassType.isSubtype(), that
1538 * is,
1539 *
1540 * <p>{@code C<S> <: C<T> if T contains S.}
1541 *
1542 * <p>Because of F-bounds, this relation can lead to infinite
1543 * recursion. Thus we must somehow break that recursion. Notice
1544 * that containsType() is only called from ClassType.isSubtype().
1545 * Since the arguments have already been checked against their
1546 * bounds, we know:
1547 *
1548 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1549 *
1550 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1551 *
1552 * @param t a type
1553 * @param s a type
1554 */
1555 public boolean containsType(Type t, Type s) {
1556 return containsType.visit(t, s);
1557 }
1558 // where
1559 private TypeRelation containsType = new TypeRelation() {
1560
1561 public Boolean visitType(Type t, Type s) {
1562 if (s.isPartial())
1563 return containedBy(s, t);
1564 else
1565 return isSameType(t, s);
1566 }
1567
1568 // void debugContainsType(WildcardType t, Type s) {
1569 // System.err.println();
1570 // System.err.format(" does %s contain %s?%n", t, s);
1571 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1572 // wildUpperBound(s), s, t, wildUpperBound(t),
1573 // t.isSuperBound()
1574 // || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t)));
1575 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1576 // wildLowerBound(t), t, s, wildLowerBound(s),
1577 // t.isExtendsBound()
1578 // || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s)));
1579 // System.err.println();
1580 // }
1581
1582 @Override
1583 public Boolean visitWildcardType(WildcardType t, Type s) {
1584 if (s.isPartial())
1585 return containedBy(s, t);
1586 else {
1587 // debugContainsType(t, s);
1588 return isSameWildcard(t, s)
1589 || isCaptureOf(s, t)
1590 || ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))) &&
1591 (t.isSuperBound() || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t))));
1592 }
1593 }
1594
1595 @Override
1596 public Boolean visitUndetVar(UndetVar t, Type s) {
1597 if (!s.hasTag(WILDCARD)) {
1598 return isSameType(t, s);
1599 } else {
1600 return false;
1601 }
1602 }
1603
1604 @Override
1605 public Boolean visitErrorType(ErrorType t, Type s) {
1606 return true;
1607 }
1608 };
1609
1610 public boolean isCaptureOf(Type s, WildcardType t) {
1611 if (!s.hasTag(TYPEVAR) || !((TypeVar)s).isCaptured())
1612 return false;
1613 return isSameWildcard(t, ((CapturedType)s).wildcard);
1614 }
1615
1616 public boolean isSameWildcard(WildcardType t, Type s) {
1617 if (!s.hasTag(WILDCARD))
1618 return false;
1619 WildcardType w = (WildcardType)s;
1620 return w.kind == t.kind && w.type == t.type;
1621 }
1622
1623 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1624 while (ts.nonEmpty() && ss.nonEmpty()
1625 && containsTypeEquivalent(ts.head, ss.head)) {
1626 ts = ts.tail;
1627 ss = ss.tail;
1628 }
1629 return ts.isEmpty() && ss.isEmpty();
1630 }
1631 // </editor-fold>
1632
1633 // <editor-fold defaultstate="collapsed" desc="isCastable">
1634 public boolean isCastable(Type t, Type s) {
1635 return isCastable(t, s, noWarnings);
1636 }
1637
1638 /**
1639 * Is t castable to s?<br>
1640 * s is assumed to be an erased type.<br>
1641 * (not defined for Method and ForAll types).
1642 */
1643 public boolean isCastable(Type t, Type s, Warner warn) {
1644 // if same type
1645 if (t == s)
1646 return true;
1647 // if one of the types is primitive
1648 if (t.isPrimitive() != s.isPrimitive()) {
1649 t = skipTypeVars(t, false);
1650 return (isConvertible(t, s, warn)
1651 || (s.isPrimitive() &&
1652 isSubtype(boxedClass(s).type, t)));
1653 }
1654 boolean result;
1655 if (warn != warnStack.head) {
1656 try {
1657 warnStack = warnStack.prepend(warn);
1658 checkUnsafeVarargsConversion(t, s, warn);
1659 result = isCastable.visit(t,s);
1660 } finally {
1661 warnStack = warnStack.tail;
1662 }
1663 } else {
1664 result = isCastable.visit(t,s);
1665 }
1666 if (result && t.hasTag(CLASS) && t.tsym.kind.matches(Kinds.KindSelector.TYP)
1667 && s.hasTag(CLASS) && s.tsym.kind.matches(Kinds.KindSelector.TYP)
1668 && (t.tsym.isSealed() || s.tsym.isSealed())) {
1669 return (t.isCompound() || s.isCompound()) ?
1670 true :
1671 !areDisjoint((ClassSymbol)t.tsym, (ClassSymbol)s.tsym);
1672 }
1673 return result;
1674 }
1675 // where
1676 private boolean areDisjoint(ClassSymbol ts, ClassSymbol ss) {
1677 if (isSubtype(erasure(ts.type), erasure(ss.type))) {
1678 return false;
1679 }
1680 // if both are classes or both are interfaces, shortcut
1681 if (ts.isInterface() == ss.isInterface() && isSubtype(erasure(ss.type), erasure(ts.type))) {
1682 return false;
1683 }
1684 if (ts.isInterface() && !ss.isInterface()) {
1685 /* so ts is interface but ss is a class
1686 * an interface is disjoint from a class if the class is disjoint form the interface
1687 */
1688 return areDisjoint(ss, ts);
1689 }
1690 // a final class that is not subtype of ss is disjoint
1691 if (!ts.isInterface() && ts.isFinal()) {
1692 return true;
1693 }
1694 // if at least one is sealed
1695 if (ts.isSealed() || ss.isSealed()) {
1696 // permitted subtypes have to be disjoint with the other symbol
1697 ClassSymbol sealedOne = ts.isSealed() ? ts : ss;
1698 ClassSymbol other = sealedOne == ts ? ss : ts;
1699 return sealedOne.permitted.stream().allMatch(sym -> areDisjoint((ClassSymbol)sym, other));
1700 }
1701 return false;
1702 }
1703
1704 private TypeRelation isCastable = new TypeRelation() {
1705
1706 public Boolean visitType(Type t, Type s) {
1707 if (s.hasTag(ERROR) || t.hasTag(NONE))
1708 return true;
1709
1710 switch (t.getTag()) {
1711 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1712 case DOUBLE:
1713 return s.isNumeric();
1714 case BOOLEAN:
1715 return s.hasTag(BOOLEAN);
1716 case VOID:
1717 return false;
1718 case BOT:
1719 return isSubtype(t, s);
1720 default:
1721 throw new AssertionError();
1722 }
1723 }
1724
1725 @Override
1726 public Boolean visitWildcardType(WildcardType t, Type s) {
1727 return isCastable(wildUpperBound(t), s, warnStack.head);
1728 }
1729
1730 @Override
1731 public Boolean visitClassType(ClassType t, Type s) {
1732 if (s.hasTag(ERROR) || s.hasTag(BOT))
1733 return true;
1734
1735 if (s.hasTag(TYPEVAR)) {
1736 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1737 warnStack.head.warn(LintCategory.UNCHECKED);
1738 return true;
1739 } else {
1740 return false;
1741 }
1742 }
1743
1744 if (t.isCompound() || s.isCompound()) {
1745 return !t.isCompound() ?
1746 visitCompoundType((ClassType)s, t, true) :
1747 visitCompoundType(t, s, false);
1748 }
1749
1750 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) {
1751 boolean upcast;
1752 if ((upcast = isSubtype(erasure(t), erasure(s)))
1753 || isSubtype(erasure(s), erasure(t))) {
1754 if (!upcast && s.hasTag(ARRAY)) {
1755 if (!isReifiable(s))
1756 warnStack.head.warn(LintCategory.UNCHECKED);
1757 return true;
1758 } else if (s.isRaw()) {
1759 return true;
1760 } else if (t.isRaw()) {
1761 if (!isUnbounded(s))
1762 warnStack.head.warn(LintCategory.UNCHECKED);
1763 return true;
1764 }
1765 // Assume |a| <: |b|
1766 final Type a = upcast ? t : s;
1767 final Type b = upcast ? s : t;
1768 final boolean HIGH = true;
1769 final boolean LOW = false;
1770 final boolean DONT_REWRITE_TYPEVARS = false;
1771 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1772 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1773 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1774 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1775 Type lowSub = asSub(bLow, aLow.tsym);
1776 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1777 if (highSub == null) {
1778 final boolean REWRITE_TYPEVARS = true;
1779 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1780 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1781 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1782 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1783 lowSub = asSub(bLow, aLow.tsym);
1784 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1785 }
1786 if (highSub != null) {
1787 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1788 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1789 }
1790 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1791 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1792 && !disjointTypes(aLow.allparams(), highSub.allparams())
1793 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1794 if (upcast ? giveWarning(a, b) :
1795 giveWarning(b, a))
1796 warnStack.head.warn(LintCategory.UNCHECKED);
1797 return true;
1798 }
1799 }
1800 if (isReifiable(s))
1801 return isSubtypeUnchecked(a, b);
1802 else
1803 return isSubtypeUnchecked(a, b, warnStack.head);
1804 }
1805
1806 // Sidecast
1807 if (s.hasTag(CLASS)) {
1808 if ((s.tsym.flags() & INTERFACE) != 0) {
1809 return ((t.tsym.flags() & FINAL) == 0)
1810 ? sideCast(t, s, warnStack.head)
1811 : sideCastFinal(t, s, warnStack.head);
1812 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1813 return ((s.tsym.flags() & FINAL) == 0)
1814 ? sideCast(t, s, warnStack.head)
1815 : sideCastFinal(t, s, warnStack.head);
1816 } else {
1817 // unrelated class types
1818 return false;
1819 }
1820 }
1821 }
1822 return false;
1823 }
1824
1825 boolean visitCompoundType(ClassType ct, Type s, boolean reverse) {
1826 Warner warn = noWarnings;
1827 for (Type c : directSupertypes(ct)) {
1828 warn.clear();
1829 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1830 return false;
1831 }
1832 if (warn.hasLint(LintCategory.UNCHECKED))
1833 warnStack.head.warn(LintCategory.UNCHECKED);
1834 return true;
1835 }
1836
1837 @Override
1838 public Boolean visitArrayType(ArrayType t, Type s) {
1839 switch (s.getTag()) {
1840 case ERROR:
1841 case BOT:
1842 return true;
1843 case TYPEVAR:
1844 if (isCastable(s, t, noWarnings)) {
1845 warnStack.head.warn(LintCategory.UNCHECKED);
1846 return true;
1847 } else {
1848 return false;
1849 }
1850 case CLASS:
1851 return isSubtype(t, s);
1852 case ARRAY:
1853 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1854 return elemtype(t).hasTag(elemtype(s).getTag());
1855 } else {
1856 return isCastable(elemtype(t), elemtype(s), warnStack.head);
1857 }
1858 default:
1859 return false;
1860 }
1861 }
1862
1863 @Override
1864 public Boolean visitTypeVar(TypeVar t, Type s) {
1865 switch (s.getTag()) {
1866 case ERROR:
1867 case BOT:
1868 return true;
1869 case TYPEVAR:
1870 if (isSubtype(t, s)) {
1871 return true;
1872 } else if (isCastable(t.getUpperBound(), s, noWarnings)) {
1873 warnStack.head.warn(LintCategory.UNCHECKED);
1874 return true;
1875 } else {
1876 return false;
1877 }
1878 default:
1879 return isCastable(t.getUpperBound(), s, warnStack.head);
1880 }
1881 }
1882
1883 @Override
1884 public Boolean visitErrorType(ErrorType t, Type s) {
1885 return true;
1886 }
1887 };
1888 // </editor-fold>
1889
1890 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1891 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1892 while (ts.tail != null && ss.tail != null) {
1893 if (disjointType(ts.head, ss.head)) return true;
1894 ts = ts.tail;
1895 ss = ss.tail;
1896 }
1897 return false;
1898 }
1899
1900 /**
1901 * Two types or wildcards are considered disjoint if it can be
1902 * proven that no type can be contained in both. It is
1903 * conservative in that it is allowed to say that two types are
1904 * not disjoint, even though they actually are.
1905 *
1906 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1907 * {@code X} and {@code Y} are not disjoint.
1908 */
1909 public boolean disjointType(Type t, Type s) {
1910 return disjointType.visit(t, s);
1911 }
1912 // where
1913 private TypeRelation disjointType = new TypeRelation() {
1914
1915 private Set<TypePair> cache = new HashSet<>();
1916
1917 @Override
1918 public Boolean visitType(Type t, Type s) {
1919 if (s.hasTag(WILDCARD))
1920 return visit(s, t);
1921 else
1922 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1923 }
1924
1925 private boolean isCastableRecursive(Type t, Type s) {
1926 TypePair pair = new TypePair(t, s);
1927 if (cache.add(pair)) {
1928 try {
1929 return Types.this.isCastable(t, s);
1930 } finally {
1931 cache.remove(pair);
1932 }
1933 } else {
1934 return true;
1935 }
1936 }
1937
1938 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1939 TypePair pair = new TypePair(t, s);
1940 if (cache.add(pair)) {
1941 try {
1942 return Types.this.notSoftSubtype(t, s);
1943 } finally {
1944 cache.remove(pair);
1945 }
1946 } else {
1947 return false;
1948 }
1949 }
1950
1951 @Override
1952 public Boolean visitWildcardType(WildcardType t, Type s) {
1953 if (t.isUnbound())
1954 return false;
1955
1956 if (!s.hasTag(WILDCARD)) {
1957 if (t.isExtendsBound())
1958 return notSoftSubtypeRecursive(s, t.type);
1959 else
1960 return notSoftSubtypeRecursive(t.type, s);
1961 }
1962
1963 if (s.isUnbound())
1964 return false;
1965
1966 if (t.isExtendsBound()) {
1967 if (s.isExtendsBound())
1968 return !isCastableRecursive(t.type, wildUpperBound(s));
1969 else if (s.isSuperBound())
1970 return notSoftSubtypeRecursive(wildLowerBound(s), t.type);
1971 } else if (t.isSuperBound()) {
1972 if (s.isExtendsBound())
1973 return notSoftSubtypeRecursive(t.type, wildUpperBound(s));
1974 }
1975 return false;
1976 }
1977 };
1978 // </editor-fold>
1979
1980 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds">
1981 public List<Type> cvarLowerBounds(List<Type> ts) {
1982 return ts.map(cvarLowerBoundMapping);
1983 }
1984 private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() {
1985 @Override
1986 public Type visitCapturedType(CapturedType t, Void _unused) {
1987 return cvarLowerBound(t);
1988 }
1989 };
1990 // </editor-fold>
1991
1992 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1993 /**
1994 * This relation answers the question: is impossible that
1995 * something of type `t' can be a subtype of `s'? This is
1996 * different from the question "is `t' not a subtype of `s'?"
1997 * when type variables are involved: Integer is not a subtype of T
1998 * where {@code <T extends Number>} but it is not true that Integer cannot
1999 * possibly be a subtype of T.
2000 */
2001 public boolean notSoftSubtype(Type t, Type s) {
2002 if (t == s) return false;
2003 if (t.hasTag(TYPEVAR)) {
2004 TypeVar tv = (TypeVar) t;
2005 return !isCastable(tv.getUpperBound(),
2006 relaxBound(s),
2007 noWarnings);
2008 }
2009 if (!s.hasTag(WILDCARD))
2010 s = cvarUpperBound(s);
2011
2012 return !isSubtype(t, relaxBound(s));
2013 }
2014
2015 private Type relaxBound(Type t) {
2016 return (t.hasTag(TYPEVAR)) ?
2017 rewriteQuantifiers(skipTypeVars(t, false), true, true) :
2018 t;
2019 }
2020 // </editor-fold>
2021
2022 // <editor-fold defaultstate="collapsed" desc="isReifiable">
2023 public boolean isReifiable(Type t) {
2024 return isReifiable.visit(t);
2025 }
2026 // where
2027 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
2028
2029 public Boolean visitType(Type t, Void ignored) {
2030 return true;
2031 }
2032
2033 @Override
2034 public Boolean visitClassType(ClassType t, Void ignored) {
2035 if (t.isCompound())
2036 return false;
2037 else {
2038 if (!t.isParameterized())
2039 return true;
2040
2041 for (Type param : t.allparams()) {
2042 if (!param.isUnbound())
2043 return false;
2044 }
2045 return true;
2046 }
2047 }
2048
2049 @Override
2050 public Boolean visitArrayType(ArrayType t, Void ignored) {
2051 return visit(t.elemtype);
2052 }
2053
2054 @Override
2055 public Boolean visitTypeVar(TypeVar t, Void ignored) {
2056 return false;
2057 }
2058 };
2059 // </editor-fold>
2060
2061 // <editor-fold defaultstate="collapsed" desc="Array Utils">
2062 public boolean isArray(Type t) {
2063 while (t.hasTag(WILDCARD))
2064 t = wildUpperBound(t);
2065 return t.hasTag(ARRAY);
2066 }
2067
2068 /**
2069 * The element type of an array.
2070 */
2071 public Type elemtype(Type t) {
2072 switch (t.getTag()) {
2073 case WILDCARD:
2074 return elemtype(wildUpperBound(t));
2075 case ARRAY:
2076 return ((ArrayType)t).elemtype;
2077 case FORALL:
2078 return elemtype(((ForAll)t).qtype);
2079 case ERROR:
2080 return t;
2081 default:
2082 return null;
2083 }
2084 }
2085
2086 public Type elemtypeOrType(Type t) {
2087 Type elemtype = elemtype(t);
2088 return elemtype != null ?
2089 elemtype :
2090 t;
2091 }
2092
2093 /**
2094 * Mapping to take element type of an arraytype
2095 */
2096 private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() {
2097 @Override
2098 public Type visitArrayType(ArrayType t, Void _unused) {
2099 return t.elemtype;
2100 }
2101
2102 @Override
2103 public Type visitTypeVar(TypeVar t, Void _unused) {
2104 return visit(skipTypeVars(t, false));
2105 }
2106 };
2107
2108 /**
2109 * The number of dimensions of an array type.
2110 */
2111 public int dimensions(Type t) {
2112 int result = 0;
2113 while (t.hasTag(ARRAY)) {
2114 result++;
2115 t = elemtype(t);
2116 }
2117 return result;
2118 }
2119
2120 /**
2121 * Returns an ArrayType with the component type t
2122 *
2123 * @param t The component type of the ArrayType
2124 * @return the ArrayType for the given component
2125 */
2126 public ArrayType makeArrayType(Type t) {
2127 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) {
2128 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
2129 }
2130 return new ArrayType(t, syms.arrayClass);
2131 }
2132 // </editor-fold>
2133
2134 // <editor-fold defaultstate="collapsed" desc="asSuper">
2135 /**
2136 * Return the (most specific) base type of t that starts with the
2137 * given symbol. If none exists, return null.
2138 *
2139 * Caveat Emptor: Since javac represents the class of all arrays with a singleton
2140 * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant,
2141 * this method could yield surprising answers when invoked on arrays. For example when
2142 * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null.
2143 *
2144 * @param t a type
2145 * @param sym a symbol
2146 */
2147 public Type asSuper(Type t, Symbol sym) {
2148 /* Some examples:
2149 *
2150 * (Enum<E>, Comparable) => Comparable<E>
2151 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind>
2152 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree
2153 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) =>
2154 * Iterable<capture#160 of ? extends c.s.s.d.DocTree>
2155 */
2156 if (sym.type == syms.objectType) { //optimization
2157 return syms.objectType;
2158 }
2159 return asSuper.visit(t, sym);
2160 }
2161 // where
2162 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
2163
2164 private Set<Symbol> seenTypes = new HashSet<>();
2165
2166 public Type visitType(Type t, Symbol sym) {
2167 return null;
2168 }
2169
2170 @Override
2171 public Type visitClassType(ClassType t, Symbol sym) {
2172 if (t.tsym == sym)
2173 return t;
2174
2175 Symbol c = t.tsym;
2176 if (!seenTypes.add(c)) {
2177 return null;
2178 }
2179 try {
2180 Type st = supertype(t);
2181 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) {
2182 Type x = asSuper(st, sym);
2183 if (x != null)
2184 return x;
2185 }
2186 if ((sym.flags() & INTERFACE) != 0) {
2187 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
2188 if (!l.head.hasTag(ERROR)) {
2189 Type x = asSuper(l.head, sym);
2190 if (x != null)
2191 return x;
2192 }
2193 }
2194 }
2195 return null;
2196 } finally {
2197 seenTypes.remove(c);
2198 }
2199 }
2200
2201 @Override
2202 public Type visitArrayType(ArrayType t, Symbol sym) {
2203 return isSubtype(t, sym.type) ? sym.type : null;
2204 }
2205
2206 @Override
2207 public Type visitTypeVar(TypeVar t, Symbol sym) {
2208 if (t.tsym == sym)
2209 return t;
2210 else
2211 return asSuper(t.getUpperBound(), sym);
2212 }
2213
2214 @Override
2215 public Type visitErrorType(ErrorType t, Symbol sym) {
2216 return t;
2217 }
2218 };
2219
2220 /**
2221 * Return the base type of t or any of its outer types that starts
2222 * with the given symbol. If none exists, return null.
2223 *
2224 * @param t a type
2225 * @param sym a symbol
2226 */
2227 public Type asOuterSuper(Type t, Symbol sym) {
2228 switch (t.getTag()) {
2229 case CLASS:
2230 do {
2231 Type s = asSuper(t, sym);
2232 if (s != null) return s;
2233 t = t.getEnclosingType();
2234 } while (t.hasTag(CLASS));
2235 return null;
2236 case ARRAY:
2237 return isSubtype(t, sym.type) ? sym.type : null;
2238 case TYPEVAR:
2239 return asSuper(t, sym);
2240 case ERROR:
2241 return t;
2242 default:
2243 return null;
2244 }
2245 }
2246
2247 /**
2248 * Return the base type of t or any of its enclosing types that
2249 * starts with the given symbol. If none exists, return null.
2250 *
2251 * @param t a type
2252 * @param sym a symbol
2253 */
2254 public Type asEnclosingSuper(Type t, Symbol sym) {
2255 switch (t.getTag()) {
2256 case CLASS:
2257 do {
2258 Type s = asSuper(t, sym);
2259 if (s != null) return s;
2260 Type outer = t.getEnclosingType();
2261 t = (outer.hasTag(CLASS)) ? outer :
2262 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
2263 Type.noType;
2264 } while (t.hasTag(CLASS));
2265 return null;
2266 case ARRAY:
2267 return isSubtype(t, sym.type) ? sym.type : null;
2268 case TYPEVAR:
2269 return asSuper(t, sym);
2270 case ERROR:
2271 return t;
2272 default:
2273 return null;
2274 }
2275 }
2276 // </editor-fold>
2277
2278 // <editor-fold defaultstate="collapsed" desc="memberType">
2279 /**
2280 * The type of given symbol, seen as a member of t.
2281 *
2282 * @param t a type
2283 * @param sym a symbol
2284 */
2285 public Type memberType(Type t, Symbol sym) {
2286 return (sym.flags() & STATIC) != 0
2287 ? sym.type
2288 : memberType.visit(t, sym);
2289 }
2290 // where
2291 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
2292
2293 public Type visitType(Type t, Symbol sym) {
2294 return sym.type;
2295 }
2296
2297 @Override
2298 public Type visitWildcardType(WildcardType t, Symbol sym) {
2299 return memberType(wildUpperBound(t), sym);
2300 }
2301
2302 @Override
2303 public Type visitClassType(ClassType t, Symbol sym) {
2304 Symbol owner = sym.owner;
2305 long flags = sym.flags();
2306 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
2307 Type base = asOuterSuper(t, owner);
2308 //if t is an intersection type T = CT & I1 & I2 ... & In
2309 //its supertypes CT, I1, ... In might contain wildcards
2310 //so we need to go through capture conversion
2311 base = t.isCompound() ? capture(base) : base;
2312 if (base != null) {
2313 List<Type> ownerParams = owner.type.allparams();
2314 List<Type> baseParams = base.allparams();
2315 if (ownerParams.nonEmpty()) {
2316 if (baseParams.isEmpty()) {
2317 // then base is a raw type
2318 return erasure(sym.type);
2319 } else {
2320 return subst(sym.type, ownerParams, baseParams);
2321 }
2322 }
2323 }
2324 }
2325 return sym.type;
2326 }
2327
2328 @Override
2329 public Type visitTypeVar(TypeVar t, Symbol sym) {
2330 return memberType(t.getUpperBound(), sym);
2331 }
2332
2333 @Override
2334 public Type visitErrorType(ErrorType t, Symbol sym) {
2335 return t;
2336 }
2337 };
2338 // </editor-fold>
2339
2340 // <editor-fold defaultstate="collapsed" desc="isAssignable">
2341 public boolean isAssignable(Type t, Type s) {
2342 return isAssignable(t, s, noWarnings);
2343 }
2344
2345 /**
2346 * Is t assignable to s?<br>
2347 * Equivalent to subtype except for constant values and raw
2348 * types.<br>
2349 * (not defined for Method and ForAll types)
2350 */
2351 public boolean isAssignable(Type t, Type s, Warner warn) {
2352 if (t.hasTag(ERROR))
2353 return true;
2354 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) {
2355 int value = ((Number)t.constValue()).intValue();
2356 switch (s.getTag()) {
2357 case BYTE:
2358 case CHAR:
2359 case SHORT:
2360 case INT:
2361 if (s.getTag().checkRange(value))
2362 return true;
2363 break;
2364 case CLASS:
2365 switch (unboxedType(s).getTag()) {
2366 case BYTE:
2367 case CHAR:
2368 case SHORT:
2369 return isAssignable(t, unboxedType(s), warn);
2370 }
2371 break;
2372 }
2373 }
2374 return isConvertible(t, s, warn);
2375 }
2376 // </editor-fold>
2377
2378 // <editor-fold defaultstate="collapsed" desc="erasure">
2379 /**
2380 * The erasure of t {@code |t|} -- the type that results when all
2381 * type parameters in t are deleted.
2382 */
2383 public Type erasure(Type t) {
2384 return eraseNotNeeded(t) ? t : erasure(t, false);
2385 }
2386 //where
2387 private boolean eraseNotNeeded(Type t) {
2388 // We don't want to erase primitive types and String type as that
2389 // operation is idempotent. Also, erasing these could result in loss
2390 // of information such as constant values attached to such types.
2391 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2392 }
2393
2394 private Type erasure(Type t, boolean recurse) {
2395 if (t.isPrimitive()) {
2396 return t; /* fast special case */
2397 } else {
2398 Type out = erasure.visit(t, recurse);
2399 return out;
2400 }
2401 }
2402 // where
2403 private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() {
2404 private Type combineMetadata(final Type s,
2405 final Type t) {
2406 if (t.getMetadata() != TypeMetadata.EMPTY) {
2407 switch (s.getKind()) {
2408 case OTHER:
2409 case UNION:
2410 case INTERSECTION:
2411 case PACKAGE:
2412 case EXECUTABLE:
2413 case NONE:
2414 case VOID:
2415 case ERROR:
2416 return s;
2417 default: return s.cloneWithMetadata(s.getMetadata().without(Kind.ANNOTATIONS));
2418 }
2419 } else {
2420 return s;
2421 }
2422 }
2423
2424 public Type visitType(Type t, Boolean recurse) {
2425 if (t.isPrimitive())
2426 return t; /*fast special case*/
2427 else {
2428 //other cases already handled
2429 return combineMetadata(t, t);
2430 }
2431 }
2432
2433 @Override
2434 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2435 Type erased = erasure(wildUpperBound(t), recurse);
2436 return combineMetadata(erased, t);
2437 }
2438
2439 @Override
2440 public Type visitClassType(ClassType t, Boolean recurse) {
2441 Type erased = t.tsym.erasure(Types.this);
2442 if (recurse) {
2443 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym,
2444 t.getMetadata().without(Kind.ANNOTATIONS));
2445 return erased;
2446 } else {
2447 return combineMetadata(erased, t);
2448 }
2449 }
2450
2451 @Override
2452 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2453 Type erased = erasure(t.getUpperBound(), recurse);
2454 return combineMetadata(erased, t);
2455 }
2456 };
2457
2458 public List<Type> erasure(List<Type> ts) {
2459 return erasure.visit(ts, false);
2460 }
2461
2462 public Type erasureRecursive(Type t) {
2463 return erasure(t, true);
2464 }
2465
2466 public List<Type> erasureRecursive(List<Type> ts) {
2467 return erasure.visit(ts, true);
2468 }
2469 // </editor-fold>
2470
2471 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType">
2472 /**
2473 * Make an intersection type from non-empty list of types. The list should be ordered according to
2474 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion.
2475 * Hence, this version of makeIntersectionType may not be called during a classfile read.
2476 *
2477 * @param bounds the types from which the intersection type is formed
2478 */
2479 public IntersectionClassType makeIntersectionType(List<Type> bounds) {
2480 return makeIntersectionType(bounds, bounds.head.tsym.isInterface());
2481 }
2482
2483 /**
2484 * Make an intersection type from non-empty list of types. The list should be ordered according to
2485 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as
2486 * an extra parameter indicates as to whether all bounds are interfaces - in which case the
2487 * supertype is implicitly assumed to be 'Object'.
2488 *
2489 * @param bounds the types from which the intersection type is formed
2490 * @param allInterfaces are all bounds interface types?
2491 */
2492 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) {
2493 Assert.check(bounds.nonEmpty());
2494 Type firstExplicitBound = bounds.head;
2495 if (allInterfaces) {
2496 bounds = bounds.prepend(syms.objectType);
2497 }
2498 ClassSymbol bc =
2499 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2500 Type.moreInfo
2501 ? names.fromString(bounds.toString())
2502 : names.empty,
2503 null,
2504 syms.noSymbol);
2505 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces);
2506 bc.type = intersectionType;
2507 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
2508 syms.objectType : // error condition, recover
2509 erasure(firstExplicitBound);
2510 bc.members_field = WriteableScope.create(bc);
2511 return intersectionType;
2512 }
2513 // </editor-fold>
2514
2515 // <editor-fold defaultstate="collapsed" desc="supertype">
2516 public Type supertype(Type t) {
2517 return supertype.visit(t);
2518 }
2519 // where
2520 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2521
2522 public Type visitType(Type t, Void ignored) {
2523 // A note on wildcards: there is no good way to
2524 // determine a supertype for a lower-bounded wildcard.
2525 return Type.noType;
2526 }
2527
2528 @Override
2529 public Type visitClassType(ClassType t, Void ignored) {
2530 if (t.supertype_field == null) {
2531 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2532 // An interface has no superclass; its supertype is Object.
2533 if (t.isInterface())
2534 supertype = ((ClassType)t.tsym.type).supertype_field;
2535 if (t.supertype_field == null) {
2536 List<Type> actuals = classBound(t).allparams();
2537 List<Type> formals = t.tsym.type.allparams();
2538 if (t.hasErasedSupertypes()) {
2539 t.supertype_field = erasureRecursive(supertype);
2540 } else if (formals.nonEmpty()) {
2541 t.supertype_field = subst(supertype, formals, actuals);
2542 }
2543 else {
2544 t.supertype_field = supertype;
2545 }
2546 }
2547 }
2548 return t.supertype_field;
2549 }
2550
2551 /**
2552 * The supertype is always a class type. If the type
2553 * variable's bounds start with a class type, this is also
2554 * the supertype. Otherwise, the supertype is
2555 * java.lang.Object.
2556 */
2557 @Override
2558 public Type visitTypeVar(TypeVar t, Void ignored) {
2559 if (t.getUpperBound().hasTag(TYPEVAR) ||
2560 (!t.getUpperBound().isCompound() && !t.getUpperBound().isInterface())) {
2561 return t.getUpperBound();
2562 } else {
2563 return supertype(t.getUpperBound());
2564 }
2565 }
2566
2567 @Override
2568 public Type visitArrayType(ArrayType t, Void ignored) {
2569 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2570 return arraySuperType();
2571 else
2572 return new ArrayType(supertype(t.elemtype), t.tsym);
2573 }
2574
2575 @Override
2576 public Type visitErrorType(ErrorType t, Void ignored) {
2577 return Type.noType;
2578 }
2579 };
2580 // </editor-fold>
2581
2582 // <editor-fold defaultstate="collapsed" desc="interfaces">
2583 /**
2584 * Return the interfaces implemented by this class.
2585 */
2586 public List<Type> interfaces(Type t) {
2587 return interfaces.visit(t);
2588 }
2589 // where
2590 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2591
2592 public List<Type> visitType(Type t, Void ignored) {
2593 return List.nil();
2594 }
2595
2596 @Override
2597 public List<Type> visitClassType(ClassType t, Void ignored) {
2598 if (t.interfaces_field == null) {
2599 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2600 if (t.interfaces_field == null) {
2601 // If t.interfaces_field is null, then t must
2602 // be a parameterized type (not to be confused
2603 // with a generic type declaration).
2604 // Terminology:
2605 // Parameterized type: List<String>
2606 // Generic type declaration: class List<E> { ... }
2607 // So t corresponds to List<String> and
2608 // t.tsym.type corresponds to List<E>.
2609 // The reason t must be parameterized type is
2610 // that completion will happen as a side
2611 // effect of calling
2612 // ClassSymbol.getInterfaces. Since
2613 // t.interfaces_field is null after
2614 // completion, we can assume that t is not the
2615 // type of a class/interface declaration.
2616 Assert.check(t != t.tsym.type, t);
2617 List<Type> actuals = t.allparams();
2618 List<Type> formals = t.tsym.type.allparams();
2619 if (t.hasErasedSupertypes()) {
2620 t.interfaces_field = erasureRecursive(interfaces);
2621 } else if (formals.nonEmpty()) {
2622 t.interfaces_field = subst(interfaces, formals, actuals);
2623 }
2624 else {
2625 t.interfaces_field = interfaces;
2626 }
2627 }
2628 }
2629 return t.interfaces_field;
2630 }
2631
2632 @Override
2633 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2634 if (t.getUpperBound().isCompound())
2635 return interfaces(t.getUpperBound());
2636
2637 if (t.getUpperBound().isInterface())
2638 return List.of(t.getUpperBound());
2639
2640 return List.nil();
2641 }
2642 };
2643
2644 public List<Type> directSupertypes(Type t) {
2645 return directSupertypes.visit(t);
2646 }
2647 // where
2648 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() {
2649
2650 public List<Type> visitType(final Type type, final Void ignored) {
2651 if (!type.isIntersection()) {
2652 final Type sup = supertype(type);
2653 return (sup == Type.noType || sup == type || sup == null)
2654 ? interfaces(type)
2655 : interfaces(type).prepend(sup);
2656 } else {
2657 return ((IntersectionClassType)type).getExplicitComponents();
2658 }
2659 }
2660 };
2661
2662 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2663 for (Type i2 : interfaces(origin.type)) {
2664 if (isym == i2.tsym) return true;
2665 }
2666 return false;
2667 }
2668 // </editor-fold>
2669
2670 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2671 Map<Type,Boolean> isDerivedRawCache = new HashMap<>();
2672
2673 public boolean isDerivedRaw(Type t) {
2674 Boolean result = isDerivedRawCache.get(t);
2675 if (result == null) {
2676 result = isDerivedRawInternal(t);
2677 isDerivedRawCache.put(t, result);
2678 }
2679 return result;
2680 }
2681
2682 public boolean isDerivedRawInternal(Type t) {
2683 if (t.isErroneous())
2684 return false;
2685 return
2686 t.isRaw() ||
2687 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) ||
2688 isDerivedRaw(interfaces(t));
2689 }
2690
2691 public boolean isDerivedRaw(List<Type> ts) {
2692 List<Type> l = ts;
2693 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2694 return l.nonEmpty();
2695 }
2696 // </editor-fold>
2697
2698 // <editor-fold defaultstate="collapsed" desc="setBounds">
2699 /**
2700 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly,
2701 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise
2702 * the supertype is simply left null (in this case, the supertype is assumed to be the head of
2703 * the bound list passed as second argument). Note that this check might cause a symbol completion.
2704 * Hence, this version of setBounds may not be called during a classfile read.
2705 *
2706 * @param t a type variable
2707 * @param bounds the bounds, must be nonempty
2708 */
2709 public void setBounds(TypeVar t, List<Type> bounds) {
2710 setBounds(t, bounds, bounds.head.tsym.isInterface());
2711 }
2712
2713 /**
2714 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds.
2715 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds
2716 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'.
2717 *
2718 * @param t a type variable
2719 * @param bounds the bounds, must be nonempty
2720 * @param allInterfaces are all bounds interface types?
2721 */
2722 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2723 t.setUpperBound( bounds.tail.isEmpty() ?
2724 bounds.head :
2725 makeIntersectionType(bounds, allInterfaces) );
2726 t.rank_field = -1;
2727 }
2728 // </editor-fold>
2729
2730 // <editor-fold defaultstate="collapsed" desc="getBounds">
2731 /**
2732 * Return list of bounds of the given type variable.
2733 */
2734 public List<Type> getBounds(TypeVar t) {
2735 if (t.getUpperBound().hasTag(NONE))
2736 return List.nil();
2737 else if (t.getUpperBound().isErroneous() || !t.getUpperBound().isCompound())
2738 return List.of(t.getUpperBound());
2739 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2740 return interfaces(t).prepend(supertype(t));
2741 else
2742 // No superclass was given in bounds.
2743 // In this case, supertype is Object, erasure is first interface.
2744 return interfaces(t);
2745 }
2746 // </editor-fold>
2747
2748 // <editor-fold defaultstate="collapsed" desc="classBound">
2749 /**
2750 * If the given type is a (possibly selected) type variable,
2751 * return the bounding class of this type, otherwise return the
2752 * type itself.
2753 */
2754 public Type classBound(Type t) {
2755 return classBound.visit(t);
2756 }
2757 // where
2758 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2759
2760 public Type visitType(Type t, Void ignored) {
2761 return t;
2762 }
2763
2764 @Override
2765 public Type visitClassType(ClassType t, Void ignored) {
2766 Type outer1 = classBound(t.getEnclosingType());
2767 if (outer1 != t.getEnclosingType())
2768 return new ClassType(outer1, t.getTypeArguments(), t.tsym,
2769 t.getMetadata());
2770 else
2771 return t;
2772 }
2773
2774 @Override
2775 public Type visitTypeVar(TypeVar t, Void ignored) {
2776 return classBound(supertype(t));
2777 }
2778
2779 @Override
2780 public Type visitErrorType(ErrorType t, Void ignored) {
2781 return t;
2782 }
2783 };
2784 // </editor-fold>
2785
2786 // <editor-fold defaultstate="collapsed" desc="subsignature / override equivalence">
2787 /**
2788 * Returns true iff the first signature is a <em>subsignature</em>
2789 * of the other. This is <b>not</b> an equivalence
2790 * relation.
2791 *
2792 * @jls 8.4.2 Method Signature
2793 * @see #overrideEquivalent(Type t, Type s)
2794 * @param t first signature (possibly raw).
2795 * @param s second signature (could be subjected to erasure).
2796 * @return true if t is a subsignature of s.
2797 */
2798 public boolean isSubSignature(Type t, Type s) {
2799 return hasSameArgs(t, s, true) || hasSameArgs(t, erasure(s), true);
2800 }
2801
2802 /**
2803 * Returns true iff these signatures are related by <em>override
2804 * equivalence</em>. This is the natural extension of
2805 * isSubSignature to an equivalence relation.
2806 *
2807 * @jls 8.4.2 Method Signature
2808 * @see #isSubSignature(Type t, Type s)
2809 * @param t a signature (possible raw, could be subjected to
2810 * erasure).
2811 * @param s a signature (possible raw, could be subjected to
2812 * erasure).
2813 * @return true if either argument is a subsignature of the other.
2814 */
2815 public boolean overrideEquivalent(Type t, Type s) {
2816 return hasSameArgs(t, s) ||
2817 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2818 }
2819
2820 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2821 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) {
2822 if (msym.overrides(sym, origin, Types.this, true)) {
2823 return true;
2824 }
2825 }
2826 return false;
2827 }
2828
2829 /**
2830 * This enum defines the strategy for implementing most specific return type check
2831 * during the most specific and functional interface checks.
2832 */
2833 public enum MostSpecificReturnCheck {
2834 /**
2835 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling
2836 * method type variables (if either method is generic) and (ii) subtyping should be replaced
2837 * by type-equivalence for primitives. This is essentially an inlined version of
2838 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been
2839 * replaced with a strict subtyping check.
2840 */
2841 BASIC() {
2842 @Override
2843 public boolean test(Type mt1, Type mt2, Types types) {
2844 List<Type> tvars = mt1.getTypeArguments();
2845 List<Type> svars = mt2.getTypeArguments();
2846 Type t = mt1.getReturnType();
2847 Type s = types.subst(mt2.getReturnType(), svars, tvars);
2848 return types.isSameType(t, s) ||
2849 !t.isPrimitive() &&
2850 !s.isPrimitive() &&
2851 types.isSubtype(t, s);
2852 }
2853 },
2854 /**
2855 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2.
2856 */
2857 RTS() {
2858 @Override
2859 public boolean test(Type mt1, Type mt2, Types types) {
2860 return types.returnTypeSubstitutable(mt1, mt2);
2861 }
2862 };
2863
2864 public abstract boolean test(Type mt1, Type mt2, Types types);
2865 }
2866
2867 /**
2868 * Merge multiple abstract methods. The preferred method is a method that is a subsignature
2869 * of all the other signatures and whose return type is more specific {@see MostSpecificReturnCheck}.
2870 * The resulting preferred method has a thrown clause that is the intersection of the merged
2871 * methods' clauses.
2872 */
2873 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) {
2874 //first check for preconditions
2875 boolean shouldErase = false;
2876 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes();
2877 for (Symbol s : ambiguousInOrder) {
2878 if ((s.flags() & ABSTRACT) == 0 ||
2879 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) {
2880 return Optional.empty();
2881 } else if (s.type.hasTag(FORALL)) {
2882 shouldErase = true;
2883 }
2884 }
2885 //then merge abstracts
2886 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) {
2887 outer: for (Symbol s : ambiguousInOrder) {
2888 Type mt = memberType(site, s);
2889 List<Type> allThrown = mt.getThrownTypes();
2890 for (Symbol s2 : ambiguousInOrder) {
2891 if (s != s2) {
2892 Type mt2 = memberType(site, s2);
2893 if (!isSubSignature(mt, mt2) ||
2894 !mostSpecificReturnCheck.test(mt, mt2, this)) {
2895 //ambiguity cannot be resolved
2896 continue outer;
2897 } else {
2898 List<Type> thrownTypes2 = mt2.getThrownTypes();
2899 if (!mt.hasTag(FORALL) && shouldErase) {
2900 thrownTypes2 = erasure(thrownTypes2);
2901 } else if (mt.hasTag(FORALL)) {
2902 //subsignature implies that if most specific is generic, then all other
2903 //methods are too
2904 Assert.check(mt2.hasTag(FORALL));
2905 // if both are generic methods, adjust thrown types ahead of intersection computation
2906 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments());
2907 }
2908 allThrown = chk.intersect(allThrown, thrownTypes2);
2909 }
2910 }
2911 }
2912 return (allThrown == mt.getThrownTypes()) ?
2913 Optional.of(s) :
2914 Optional.of(new MethodSymbol(
2915 s.flags(),
2916 s.name,
2917 createMethodTypeWithThrown(s.type, allThrown),
2918 s.owner) {
2919 @Override
2920 public Symbol baseSymbol() {
2921 return s;
2922 }
2923 });
2924 }
2925 }
2926 return Optional.empty();
2927 }
2928
2929 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2930 class ImplementationCache {
2931
2932 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>();
2933
2934 class Entry {
2935 final MethodSymbol cachedImpl;
2936 final Predicate<Symbol> implFilter;
2937 final boolean checkResult;
2938 final int prevMark;
2939
2940 public Entry(MethodSymbol cachedImpl,
2941 Predicate<Symbol> scopeFilter,
2942 boolean checkResult,
2943 int prevMark) {
2944 this.cachedImpl = cachedImpl;
2945 this.implFilter = scopeFilter;
2946 this.checkResult = checkResult;
2947 this.prevMark = prevMark;
2948 }
2949
2950 boolean matches(Predicate<Symbol> scopeFilter, boolean checkResult, int mark) {
2951 return this.implFilter == scopeFilter &&
2952 this.checkResult == checkResult &&
2953 this.prevMark == mark;
2954 }
2955 }
2956
2957 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2958 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2959 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2960 if (cache == null) {
2961 cache = new HashMap<>();
2962 _map.put(ms, new SoftReference<>(cache));
2963 }
2964 Entry e = cache.get(origin);
2965 CompoundScope members = membersClosure(origin.type, true);
2966 if (e == null ||
2967 !e.matches(implFilter, checkResult, members.getMark())) {
2968 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2969 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2970 return impl;
2971 }
2972 else {
2973 return e.cachedImpl;
2974 }
2975 }
2976
2977 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2978 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
2979 t = skipTypeVars(t, false);
2980 TypeSymbol c = t.tsym;
2981 Symbol bestSoFar = null;
2982 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) {
2983 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) {
2984 bestSoFar = sym;
2985 if ((sym.flags() & ABSTRACT) == 0) {
2986 //if concrete impl is found, exit immediately
2987 break;
2988 }
2989 }
2990 }
2991 if (bestSoFar != null) {
2992 //return either the (only) concrete implementation or the first abstract one
2993 return (MethodSymbol)bestSoFar;
2994 }
2995 }
2996 return null;
2997 }
2998 }
2999
3000 private ImplementationCache implCache = new ImplementationCache();
3001
3002 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
3003 return implCache.get(ms, origin, checkResult, implFilter);
3004 }
3005 // </editor-fold>
3006
3007 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
3008 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> {
3009
3010 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>();
3011
3012 Set<TypeSymbol> seenTypes = new HashSet<>();
3013
3014 class MembersScope extends CompoundScope {
3015
3016 CompoundScope scope;
3017
3018 public MembersScope(CompoundScope scope) {
3019 super(scope.owner);
3020 this.scope = scope;
3021 }
3022
3023 Predicate<Symbol> combine(Predicate<Symbol> sf) {
3024 return s -> !s.owner.isInterface() && (sf == null || sf.test(s));
3025 }
3026
3027 @Override
3028 public Iterable<Symbol> getSymbols(Predicate<Symbol> sf, LookupKind lookupKind) {
3029 return scope.getSymbols(combine(sf), lookupKind);
3030 }
3031
3032 @Override
3033 public Iterable<Symbol> getSymbolsByName(Name name, Predicate<Symbol> sf, LookupKind lookupKind) {
3034 return scope.getSymbolsByName(name, combine(sf), lookupKind);
3035 }
3036
3037 @Override
3038 public int getMark() {
3039 return scope.getMark();
3040 }
3041 }
3042
3043 CompoundScope nilScope;
3044
3045 /** members closure visitor methods **/
3046
3047 public CompoundScope visitType(Type t, Void _unused) {
3048 if (nilScope == null) {
3049 nilScope = new CompoundScope(syms.noSymbol);
3050 }
3051 return nilScope;
3052 }
3053
3054 @Override
3055 public CompoundScope visitClassType(ClassType t, Void _unused) {
3056 if (!seenTypes.add(t.tsym)) {
3057 //this is possible when an interface is implemented in multiple
3058 //superclasses, or when a class hierarchy is circular - in such
3059 //cases we don't need to recurse (empty scope is returned)
3060 return new CompoundScope(t.tsym);
3061 }
3062 try {
3063 seenTypes.add(t.tsym);
3064 ClassSymbol csym = (ClassSymbol)t.tsym;
3065 CompoundScope membersClosure = _map.get(csym);
3066 if (membersClosure == null) {
3067 membersClosure = new CompoundScope(csym);
3068 for (Type i : interfaces(t)) {
3069 membersClosure.prependSubScope(visit(i, null));
3070 }
3071 membersClosure.prependSubScope(visit(supertype(t), null));
3072 membersClosure.prependSubScope(csym.members());
3073 _map.put(csym, membersClosure);
3074 }
3075 return membersClosure;
3076 }
3077 finally {
3078 seenTypes.remove(t.tsym);
3079 }
3080 }
3081
3082 @Override
3083 public CompoundScope visitTypeVar(TypeVar t, Void _unused) {
3084 return visit(t.getUpperBound(), null);
3085 }
3086 }
3087
3088 private MembersClosureCache membersCache = new MembersClosureCache();
3089
3090 public CompoundScope membersClosure(Type site, boolean skipInterface) {
3091 CompoundScope cs = membersCache.visit(site, null);
3092 Assert.checkNonNull(cs, () -> "type " + site);
3093 return skipInterface ? membersCache.new MembersScope(cs) : cs;
3094 }
3095 // </editor-fold>
3096
3097
3098 /** Return first abstract member of class `sym'.
3099 */
3100 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) {
3101 try {
3102 return firstUnimplementedAbstractImpl(sym, sym);
3103 } catch (CompletionFailure ex) {
3104 chk.completionError(enter.getEnv(sym).tree.pos(), ex);
3105 return null;
3106 }
3107 }
3108 //where:
3109 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) {
3110 MethodSymbol undef = null;
3111 // Do not bother to search in classes that are not abstract,
3112 // since they cannot have abstract members.
3113 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
3114 Scope s = c.members();
3115 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
3116 if (sym.kind == MTH &&
3117 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
3118 MethodSymbol absmeth = (MethodSymbol)sym;
3119 MethodSymbol implmeth = absmeth.implementation(impl, this, true);
3120 if (implmeth == null || implmeth == absmeth) {
3121 //look for default implementations
3122 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head;
3123 if (prov != null && prov.overrides(absmeth, impl, this, true)) {
3124 implmeth = prov;
3125 }
3126 }
3127 if (implmeth == null || implmeth == absmeth) {
3128 undef = absmeth;
3129 break;
3130 }
3131 }
3132 }
3133 if (undef == null) {
3134 Type st = supertype(c.type);
3135 if (st.hasTag(CLASS))
3136 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym);
3137 }
3138 for (List<Type> l = interfaces(c.type);
3139 undef == null && l.nonEmpty();
3140 l = l.tail) {
3141 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym);
3142 }
3143 }
3144 return undef;
3145 }
3146
3147 public class CandidatesCache {
3148 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>();
3149
3150 class Entry {
3151 Type site;
3152 MethodSymbol msym;
3153
3154 Entry(Type site, MethodSymbol msym) {
3155 this.site = site;
3156 this.msym = msym;
3157 }
3158
3159 @Override
3160 public boolean equals(Object obj) {
3161 return (obj instanceof Entry entry)
3162 && entry.msym == msym
3163 && isSameType(site, entry.site);
3164 }
3165
3166 @Override
3167 public int hashCode() {
3168 return Types.this.hashCode(site) & ~msym.hashCode();
3169 }
3170 }
3171
3172 public List<MethodSymbol> get(Entry e) {
3173 return cache.get(e);
3174 }
3175
3176 public void put(Entry e, List<MethodSymbol> msymbols) {
3177 cache.put(e, msymbols);
3178 }
3179 }
3180
3181 public CandidatesCache candidatesCache = new CandidatesCache();
3182
3183 //where
3184 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
3185 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms);
3186 List<MethodSymbol> candidates = candidatesCache.get(e);
3187 if (candidates == null) {
3188 Predicate<Symbol> filter = new MethodFilter(ms, site);
3189 List<MethodSymbol> candidates2 = List.nil();
3190 for (Symbol s : membersClosure(site, false).getSymbols(filter)) {
3191 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
3192 return List.of((MethodSymbol)s);
3193 } else if (!candidates2.contains(s)) {
3194 candidates2 = candidates2.prepend((MethodSymbol)s);
3195 }
3196 }
3197 candidates = prune(candidates2);
3198 candidatesCache.put(e, candidates);
3199 }
3200 return candidates;
3201 }
3202
3203 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
3204 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>();
3205 for (MethodSymbol m1 : methods) {
3206 boolean isMin_m1 = true;
3207 for (MethodSymbol m2 : methods) {
3208 if (m1 == m2) continue;
3209 if (m2.owner != m1.owner &&
3210 asSuper(m2.owner.type, m1.owner) != null) {
3211 isMin_m1 = false;
3212 break;
3213 }
3214 }
3215 if (isMin_m1)
3216 methodsMin.append(m1);
3217 }
3218 return methodsMin.toList();
3219 }
3220 // where
3221 private class MethodFilter implements Predicate<Symbol> {
3222
3223 Symbol msym;
3224 Type site;
3225
3226 MethodFilter(Symbol msym, Type site) {
3227 this.msym = msym;
3228 this.site = site;
3229 }
3230
3231 @Override
3232 public boolean test(Symbol s) {
3233 return s.kind == MTH &&
3234 s.name == msym.name &&
3235 (s.flags() & SYNTHETIC) == 0 &&
3236 s.isInheritedIn(site.tsym, Types.this) &&
3237 overrideEquivalent(memberType(site, s), memberType(site, msym));
3238 }
3239 }
3240 // </editor-fold>
3241
3242 /**
3243 * Does t have the same arguments as s? It is assumed that both
3244 * types are (possibly polymorphic) method types. Monomorphic
3245 * method types "have the same arguments", if their argument lists
3246 * are equal. Polymorphic method types "have the same arguments",
3247 * if they have the same arguments after renaming all type
3248 * variables of one to corresponding type variables in the other,
3249 * where correspondence is by position in the type parameter list.
3250 */
3251 public boolean hasSameArgs(Type t, Type s) {
3252 return hasSameArgs(t, s, true);
3253 }
3254
3255 public boolean hasSameArgs(Type t, Type s, boolean strict) {
3256 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
3257 }
3258
3259 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
3260 return hasSameArgs.visit(t, s);
3261 }
3262 // where
3263 private class HasSameArgs extends TypeRelation {
3264
3265 boolean strict;
3266
3267 public HasSameArgs(boolean strict) {
3268 this.strict = strict;
3269 }
3270
3271 public Boolean visitType(Type t, Type s) {
3272 throw new AssertionError();
3273 }
3274
3275 @Override
3276 public Boolean visitMethodType(MethodType t, Type s) {
3277 return s.hasTag(METHOD)
3278 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
3279 }
3280
3281 @Override
3282 public Boolean visitForAll(ForAll t, Type s) {
3283 if (!s.hasTag(FORALL))
3284 return strict ? false : visitMethodType(t.asMethodType(), s);
3285
3286 ForAll forAll = (ForAll)s;
3287 return hasSameBounds(t, forAll)
3288 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
3289 }
3290
3291 @Override
3292 public Boolean visitErrorType(ErrorType t, Type s) {
3293 return false;
3294 }
3295 }
3296
3297 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
3298 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
3299
3300 // </editor-fold>
3301
3302 // <editor-fold defaultstate="collapsed" desc="subst">
3303 public List<Type> subst(List<Type> ts,
3304 List<Type> from,
3305 List<Type> to) {
3306 return ts.map(new Subst(from, to));
3307 }
3308
3309 /**
3310 * Substitute all occurrences of a type in `from' with the
3311 * corresponding type in `to' in 't'. Match lists `from' and `to'
3312 * from the right: If lists have different length, discard leading
3313 * elements of the longer list.
3314 */
3315 public Type subst(Type t, List<Type> from, List<Type> to) {
3316 return t.map(new Subst(from, to));
3317 }
3318
3319 private class Subst extends StructuralTypeMapping<Void> {
3320 List<Type> from;
3321 List<Type> to;
3322
3323 public Subst(List<Type> from, List<Type> to) {
3324 int fromLength = from.length();
3325 int toLength = to.length();
3326 while (fromLength > toLength) {
3327 fromLength--;
3328 from = from.tail;
3329 }
3330 while (fromLength < toLength) {
3331 toLength--;
3332 to = to.tail;
3333 }
3334 this.from = from;
3335 this.to = to;
3336 }
3337
3338 @Override
3339 public Type visitTypeVar(TypeVar t, Void ignored) {
3340 for (List<Type> from = this.from, to = this.to;
3341 from.nonEmpty();
3342 from = from.tail, to = to.tail) {
3343 if (t.equalsIgnoreMetadata(from.head)) {
3344 return to.head.withTypeVar(t);
3345 }
3346 }
3347 return t;
3348 }
3349
3350 @Override
3351 public Type visitClassType(ClassType t, Void ignored) {
3352 if (!t.isCompound()) {
3353 return super.visitClassType(t, ignored);
3354 } else {
3355 Type st = visit(supertype(t));
3356 List<Type> is = visit(interfaces(t), ignored);
3357 if (st == supertype(t) && is == interfaces(t))
3358 return t;
3359 else
3360 return makeIntersectionType(is.prepend(st));
3361 }
3362 }
3363
3364 @Override
3365 public Type visitWildcardType(WildcardType t, Void ignored) {
3366 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored);
3367 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) {
3368 t2.type = wildUpperBound(t2.type);
3369 }
3370 return t2;
3371 }
3372
3373 @Override
3374 public Type visitForAll(ForAll t, Void ignored) {
3375 if (Type.containsAny(to, t.tvars)) {
3376 //perform alpha-renaming of free-variables in 't'
3377 //if 'to' types contain variables that are free in 't'
3378 List<Type> freevars = newInstances(t.tvars);
3379 t = new ForAll(freevars,
3380 Types.this.subst(t.qtype, t.tvars, freevars));
3381 }
3382 List<Type> tvars1 = substBounds(t.tvars, from, to);
3383 Type qtype1 = visit(t.qtype);
3384 if (tvars1 == t.tvars && qtype1 == t.qtype) {
3385 return t;
3386 } else if (tvars1 == t.tvars) {
3387 return new ForAll(tvars1, qtype1) {
3388 @Override
3389 public boolean needsStripping() {
3390 return true;
3391 }
3392 };
3393 } else {
3394 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) {
3395 @Override
3396 public boolean needsStripping() {
3397 return true;
3398 }
3399 };
3400 }
3401 }
3402 }
3403
3404 public List<Type> substBounds(List<Type> tvars,
3405 List<Type> from,
3406 List<Type> to) {
3407 if (tvars.isEmpty())
3408 return tvars;
3409 ListBuffer<Type> newBoundsBuf = new ListBuffer<>();
3410 boolean changed = false;
3411 // calculate new bounds
3412 for (Type t : tvars) {
3413 TypeVar tv = (TypeVar) t;
3414 Type bound = subst(tv.getUpperBound(), from, to);
3415 if (bound != tv.getUpperBound())
3416 changed = true;
3417 newBoundsBuf.append(bound);
3418 }
3419 if (!changed)
3420 return tvars;
3421 ListBuffer<Type> newTvars = new ListBuffer<>();
3422 // create new type variables without bounds
3423 for (Type t : tvars) {
3424 newTvars.append(new TypeVar(t.tsym, null, syms.botType,
3425 t.getMetadata()));
3426 }
3427 // the new bounds should use the new type variables in place
3428 // of the old
3429 List<Type> newBounds = newBoundsBuf.toList();
3430 from = tvars;
3431 to = newTvars.toList();
3432 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
3433 newBounds.head = subst(newBounds.head, from, to);
3434 }
3435 newBounds = newBoundsBuf.toList();
3436 // set the bounds of new type variables to the new bounds
3437 for (Type t : newTvars.toList()) {
3438 TypeVar tv = (TypeVar) t;
3439 tv.setUpperBound( newBounds.head );
3440 newBounds = newBounds.tail;
3441 }
3442 return newTvars.toList();
3443 }
3444
3445 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
3446 Type bound1 = subst(t.getUpperBound(), from, to);
3447 if (bound1 == t.getUpperBound())
3448 return t;
3449 else {
3450 // create new type variable without bounds
3451 TypeVar tv = new TypeVar(t.tsym, null, syms.botType,
3452 t.getMetadata());
3453 // the new bound should use the new type variable in place
3454 // of the old
3455 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) );
3456 return tv;
3457 }
3458 }
3459 // </editor-fold>
3460
3461 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
3462 /**
3463 * Does t have the same bounds for quantified variables as s?
3464 */
3465 public boolean hasSameBounds(ForAll t, ForAll s) {
3466 List<Type> l1 = t.tvars;
3467 List<Type> l2 = s.tvars;
3468 while (l1.nonEmpty() && l2.nonEmpty() &&
3469 isSameType(l1.head.getUpperBound(),
3470 subst(l2.head.getUpperBound(),
3471 s.tvars,
3472 t.tvars))) {
3473 l1 = l1.tail;
3474 l2 = l2.tail;
3475 }
3476 return l1.isEmpty() && l2.isEmpty();
3477 }
3478 // </editor-fold>
3479
3480 // <editor-fold defaultstate="collapsed" desc="newInstances">
3481 /** Create new vector of type variables from list of variables
3482 * changing all recursive bounds from old to new list.
3483 */
3484 public List<Type> newInstances(List<Type> tvars) {
3485 List<Type> tvars1 = tvars.map(newInstanceFun);
3486 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
3487 TypeVar tv = (TypeVar) l.head;
3488 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) );
3489 }
3490 return tvars1;
3491 }
3492 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() {
3493 @Override
3494 public TypeVar visitTypeVar(TypeVar t, Void _unused) {
3495 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata());
3496 }
3497 };
3498 // </editor-fold>
3499
3500 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
3501 return original.accept(methodWithParameters, newParams);
3502 }
3503 // where
3504 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
3505 public Type visitType(Type t, List<Type> newParams) {
3506 throw new IllegalArgumentException("Not a method type: " + t);
3507 }
3508 public Type visitMethodType(MethodType t, List<Type> newParams) {
3509 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
3510 }
3511 public Type visitForAll(ForAll t, List<Type> newParams) {
3512 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
3513 }
3514 };
3515
3516 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
3517 return original.accept(methodWithThrown, newThrown);
3518 }
3519 // where
3520 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
3521 public Type visitType(Type t, List<Type> newThrown) {
3522 throw new IllegalArgumentException("Not a method type: " + t);
3523 }
3524 public Type visitMethodType(MethodType t, List<Type> newThrown) {
3525 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
3526 }
3527 public Type visitForAll(ForAll t, List<Type> newThrown) {
3528 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
3529 }
3530 };
3531
3532 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
3533 return original.accept(methodWithReturn, newReturn);
3534 }
3535 // where
3536 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
3537 public Type visitType(Type t, Type newReturn) {
3538 throw new IllegalArgumentException("Not a method type: " + t);
3539 }
3540 public Type visitMethodType(MethodType t, Type newReturn) {
3541 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) {
3542 @Override
3543 public Type baseType() {
3544 return t;
3545 }
3546 };
3547 }
3548 public Type visitForAll(ForAll t, Type newReturn) {
3549 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) {
3550 @Override
3551 public Type baseType() {
3552 return t;
3553 }
3554 };
3555 }
3556 };
3557
3558 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3559 public Type createErrorType(Type originalType) {
3560 return new ErrorType(originalType, syms.errSymbol);
3561 }
3562
3563 public Type createErrorType(ClassSymbol c, Type originalType) {
3564 return new ErrorType(c, originalType);
3565 }
3566
3567 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3568 return new ErrorType(name, container, originalType);
3569 }
3570 // </editor-fold>
3571
3572 // <editor-fold defaultstate="collapsed" desc="rank">
3573 /**
3574 * The rank of a class is the length of the longest path between
3575 * the class and java.lang.Object in the class inheritance
3576 * graph. Undefined for all but reference types.
3577 */
3578 public int rank(Type t) {
3579 switch(t.getTag()) {
3580 case CLASS: {
3581 ClassType cls = (ClassType)t;
3582 if (cls.rank_field < 0) {
3583 Name fullname = cls.tsym.getQualifiedName();
3584 if (fullname == names.java_lang_Object)
3585 cls.rank_field = 0;
3586 else {
3587 int r = rank(supertype(cls));
3588 for (List<Type> l = interfaces(cls);
3589 l.nonEmpty();
3590 l = l.tail) {
3591 if (rank(l.head) > r)
3592 r = rank(l.head);
3593 }
3594 cls.rank_field = r + 1;
3595 }
3596 }
3597 return cls.rank_field;
3598 }
3599 case TYPEVAR: {
3600 TypeVar tvar = (TypeVar)t;
3601 if (tvar.rank_field < 0) {
3602 int r = rank(supertype(tvar));
3603 for (List<Type> l = interfaces(tvar);
3604 l.nonEmpty();
3605 l = l.tail) {
3606 if (rank(l.head) > r) r = rank(l.head);
3607 }
3608 tvar.rank_field = r + 1;
3609 }
3610 return tvar.rank_field;
3611 }
3612 case ERROR:
3613 case NONE:
3614 return 0;
3615 default:
3616 throw new AssertionError();
3617 }
3618 }
3619 // </editor-fold>
3620
3621 /** Cache the symbol to reflect the qualifying type.
3622 * key: corresponding type
3623 * value: qualified symbol
3624 */
3625 private Map<Type, Symbol> qualifiedSymbolCache;
3626
3627 public void clearQualifiedSymbolCache() {
3628 qualifiedSymbolCache.clear();
3629 }
3630
3631 /** Construct a symbol to reflect the qualifying type that should
3632 * appear in the byte code as per JLS 13.1.
3633 *
3634 * For {@literal target >= 1.2}: Clone a method with the qualifier as owner (except
3635 * for those cases where we need to work around VM bugs).
3636 *
3637 * For {@literal target <= 1.1}: If qualified variable or method is defined in a
3638 * non-accessible class, clone it with the qualifier class as owner.
3639 *
3640 * @param sym The accessed symbol
3641 * @param site The qualifier's type.
3642 */
3643 public Symbol binaryQualifier(Symbol sym, Type site) {
3644
3645 if (site.hasTag(ARRAY)) {
3646 if (sym == syms.lengthVar ||
3647 sym.owner != syms.arrayClass)
3648 return sym;
3649 // array clone can be qualified by the array type in later targets
3650 Symbol qualifier;
3651 if ((qualifier = qualifiedSymbolCache.get(site)) == null) {
3652 qualifier = new ClassSymbol(Flags.PUBLIC, site.tsym.name, site, syms.noSymbol);
3653 qualifiedSymbolCache.put(site, qualifier);
3654 }
3655 return sym.clone(qualifier);
3656 }
3657
3658 if (sym.owner == site.tsym ||
3659 (sym.flags() & (STATIC | SYNTHETIC)) == (STATIC | SYNTHETIC)) {
3660 return sym;
3661 }
3662
3663 // leave alone methods inherited from Object
3664 // JLS 13.1.
3665 if (sym.owner == syms.objectType.tsym)
3666 return sym;
3667
3668 return sym.clone(site.tsym);
3669 }
3670
3671 /**
3672 * Helper method for generating a string representation of a given type
3673 * accordingly to a given locale
3674 */
3675 public String toString(Type t, Locale locale) {
3676 return Printer.createStandardPrinter(messages).visit(t, locale);
3677 }
3678
3679 /**
3680 * Helper method for generating a string representation of a given type
3681 * accordingly to a given locale
3682 */
3683 public String toString(Symbol t, Locale locale) {
3684 return Printer.createStandardPrinter(messages).visit(t, locale);
3685 }
3686
3687 // <editor-fold defaultstate="collapsed" desc="toString">
3688 /**
3689 * This toString is slightly more descriptive than the one on Type.
3690 *
3691 * @deprecated Types.toString(Type t, Locale l) provides better support
3692 * for localization
3693 */
3694 @Deprecated
3695 public String toString(Type t) {
3696 if (t.hasTag(FORALL)) {
3697 ForAll forAll = (ForAll)t;
3698 return typaramsString(forAll.tvars) + forAll.qtype;
3699 }
3700 return "" + t;
3701 }
3702 // where
3703 private String typaramsString(List<Type> tvars) {
3704 StringBuilder s = new StringBuilder();
3705 s.append('<');
3706 boolean first = true;
3707 for (Type t : tvars) {
3708 if (!first) s.append(", ");
3709 first = false;
3710 appendTyparamString(((TypeVar)t), s);
3711 }
3712 s.append('>');
3713 return s.toString();
3714 }
3715 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3716 buf.append(t);
3717 if (t.getUpperBound() == null ||
3718 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object)
3719 return;
3720 buf.append(" extends "); // Java syntax; no need for i18n
3721 Type bound = t.getUpperBound();
3722 if (!bound.isCompound()) {
3723 buf.append(bound);
3724 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3725 buf.append(supertype(t));
3726 for (Type intf : interfaces(t)) {
3727 buf.append('&');
3728 buf.append(intf);
3729 }
3730 } else {
3731 // No superclass was given in bounds.
3732 // In this case, supertype is Object, erasure is first interface.
3733 boolean first = true;
3734 for (Type intf : interfaces(t)) {
3735 if (!first) buf.append('&');
3736 first = false;
3737 buf.append(intf);
3738 }
3739 }
3740 }
3741 // </editor-fold>
3742
3743 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3744 /**
3745 * A cache for closures.
3746 *
3747 * <p>A closure is a list of all the supertypes and interfaces of
3748 * a class or interface type, ordered by ClassSymbol.precedes
3749 * (that is, subclasses come first, arbitrary but fixed
3750 * otherwise).
3751 */
3752 private Map<Type,List<Type>> closureCache = new HashMap<>();
3753
3754 /**
3755 * Returns the closure of a class or interface type.
3756 */
3757 public List<Type> closure(Type t) {
3758 List<Type> cl = closureCache.get(t);
3759 if (cl == null) {
3760 Type st = supertype(t);
3761 if (!t.isCompound()) {
3762 if (st.hasTag(CLASS)) {
3763 cl = insert(closure(st), t);
3764 } else if (st.hasTag(TYPEVAR)) {
3765 cl = closure(st).prepend(t);
3766 } else {
3767 cl = List.of(t);
3768 }
3769 } else {
3770 cl = closure(supertype(t));
3771 }
3772 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3773 cl = union(cl, closure(l.head));
3774 closureCache.put(t, cl);
3775 }
3776 return cl;
3777 }
3778
3779 /**
3780 * Collect types into a new closure (using a @code{ClosureHolder})
3781 */
3782 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3783 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip),
3784 ClosureHolder::add,
3785 ClosureHolder::merge,
3786 ClosureHolder::closure);
3787 }
3788 //where
3789 class ClosureHolder {
3790 List<Type> closure;
3791 final boolean minClosure;
3792 final BiPredicate<Type, Type> shouldSkip;
3793
3794 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3795 this.closure = List.nil();
3796 this.minClosure = minClosure;
3797 this.shouldSkip = shouldSkip;
3798 }
3799
3800 void add(Type type) {
3801 closure = insert(closure, type, shouldSkip);
3802 }
3803
3804 ClosureHolder merge(ClosureHolder other) {
3805 closure = union(closure, other.closure, shouldSkip);
3806 return this;
3807 }
3808
3809 List<Type> closure() {
3810 return minClosure ? closureMin(closure) : closure;
3811 }
3812 }
3813
3814 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym;
3815
3816 /**
3817 * Insert a type in a closure
3818 */
3819 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) {
3820 if (cl.isEmpty()) {
3821 return cl.prepend(t);
3822 } else if (shouldSkip.test(t, cl.head)) {
3823 return cl;
3824 } else if (t.tsym.precedes(cl.head.tsym, this)) {
3825 return cl.prepend(t);
3826 } else {
3827 // t comes after head, or the two are unrelated
3828 return insert(cl.tail, t, shouldSkip).prepend(cl.head);
3829 }
3830 }
3831
3832 public List<Type> insert(List<Type> cl, Type t) {
3833 return insert(cl, t, basicClosureSkip);
3834 }
3835
3836 /**
3837 * Form the union of two closures
3838 */
3839 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) {
3840 if (cl1.isEmpty()) {
3841 return cl2;
3842 } else if (cl2.isEmpty()) {
3843 return cl1;
3844 } else if (shouldSkip.test(cl1.head, cl2.head)) {
3845 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
3846 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3847 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
3848 } else {
3849 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
3850 }
3851 }
3852
3853 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3854 return union(cl1, cl2, basicClosureSkip);
3855 }
3856
3857 /**
3858 * Intersect two closures
3859 */
3860 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3861 if (cl1 == cl2)
3862 return cl1;
3863 if (cl1.isEmpty() || cl2.isEmpty())
3864 return List.nil();
3865 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3866 return intersect(cl1.tail, cl2);
3867 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3868 return intersect(cl1, cl2.tail);
3869 if (isSameType(cl1.head, cl2.head))
3870 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3871 if (cl1.head.tsym == cl2.head.tsym &&
3872 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) {
3873 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3874 Type merge = merge(cl1.head,cl2.head);
3875 return intersect(cl1.tail, cl2.tail).prepend(merge);
3876 }
3877 if (cl1.head.isRaw() || cl2.head.isRaw())
3878 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3879 }
3880 return intersect(cl1.tail, cl2.tail);
3881 }
3882 // where
3883 class TypePair {
3884 final Type t1;
3885 final Type t2;;
3886
3887 TypePair(Type t1, Type t2) {
3888 this.t1 = t1;
3889 this.t2 = t2;
3890 }
3891 @Override
3892 public int hashCode() {
3893 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3894 }
3895 @Override
3896 public boolean equals(Object obj) {
3897 return (obj instanceof TypePair typePair)
3898 && isSameType(t1, typePair.t1)
3899 && isSameType(t2, typePair.t2);
3900 }
3901 }
3902 Set<TypePair> mergeCache = new HashSet<>();
3903 private Type merge(Type c1, Type c2) {
3904 ClassType class1 = (ClassType) c1;
3905 List<Type> act1 = class1.getTypeArguments();
3906 ClassType class2 = (ClassType) c2;
3907 List<Type> act2 = class2.getTypeArguments();
3908 ListBuffer<Type> merged = new ListBuffer<>();
3909 List<Type> typarams = class1.tsym.type.getTypeArguments();
3910
3911 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3912 if (containsType(act1.head, act2.head)) {
3913 merged.append(act1.head);
3914 } else if (containsType(act2.head, act1.head)) {
3915 merged.append(act2.head);
3916 } else {
3917 TypePair pair = new TypePair(c1, c2);
3918 Type m;
3919 if (mergeCache.add(pair)) {
3920 m = new WildcardType(lub(wildUpperBound(act1.head),
3921 wildUpperBound(act2.head)),
3922 BoundKind.EXTENDS,
3923 syms.boundClass);
3924 mergeCache.remove(pair);
3925 } else {
3926 m = new WildcardType(syms.objectType,
3927 BoundKind.UNBOUND,
3928 syms.boundClass);
3929 }
3930 merged.append(m.withTypeVar(typarams.head));
3931 }
3932 act1 = act1.tail;
3933 act2 = act2.tail;
3934 typarams = typarams.tail;
3935 }
3936 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3937 // There is no spec detailing how type annotations are to
3938 // be inherited. So set it to noAnnotations for now
3939 return new ClassType(class1.getEnclosingType(), merged.toList(),
3940 class1.tsym);
3941 }
3942
3943 /**
3944 * Return the minimum type of a closure, a compound type if no
3945 * unique minimum exists.
3946 */
3947 private Type compoundMin(List<Type> cl) {
3948 if (cl.isEmpty()) return syms.objectType;
3949 List<Type> compound = closureMin(cl);
3950 if (compound.isEmpty())
3951 return null;
3952 else if (compound.tail.isEmpty())
3953 return compound.head;
3954 else
3955 return makeIntersectionType(compound);
3956 }
3957
3958 /**
3959 * Return the minimum types of a closure, suitable for computing
3960 * compoundMin or glb.
3961 */
3962 private List<Type> closureMin(List<Type> cl) {
3963 ListBuffer<Type> classes = new ListBuffer<>();
3964 ListBuffer<Type> interfaces = new ListBuffer<>();
3965 Set<Type> toSkip = new HashSet<>();
3966 while (!cl.isEmpty()) {
3967 Type current = cl.head;
3968 boolean keep = !toSkip.contains(current);
3969 if (keep && current.hasTag(TYPEVAR)) {
3970 // skip lower-bounded variables with a subtype in cl.tail
3971 for (Type t : cl.tail) {
3972 if (isSubtypeNoCapture(t, current)) {
3973 keep = false;
3974 break;
3975 }
3976 }
3977 }
3978 if (keep) {
3979 if (current.isInterface())
3980 interfaces.append(current);
3981 else
3982 classes.append(current);
3983 for (Type t : cl.tail) {
3984 // skip supertypes of 'current' in cl.tail
3985 if (isSubtypeNoCapture(current, t))
3986 toSkip.add(t);
3987 }
3988 }
3989 cl = cl.tail;
3990 }
3991 return classes.appendList(interfaces).toList();
3992 }
3993
3994 /**
3995 * Return the least upper bound of list of types. if the lub does
3996 * not exist return null.
3997 */
3998 public Type lub(List<Type> ts) {
3999 return lub(ts.toArray(new Type[ts.length()]));
4000 }
4001
4002 /**
4003 * Return the least upper bound (lub) of set of types. If the lub
4004 * does not exist return the type of null (bottom).
4005 */
4006 public Type lub(Type... ts) {
4007 final int UNKNOWN_BOUND = 0;
4008 final int ARRAY_BOUND = 1;
4009 final int CLASS_BOUND = 2;
4010
4011 int[] kinds = new int[ts.length];
4012
4013 int boundkind = UNKNOWN_BOUND;
4014 for (int i = 0 ; i < ts.length ; i++) {
4015 Type t = ts[i];
4016 switch (t.getTag()) {
4017 case CLASS:
4018 boundkind |= kinds[i] = CLASS_BOUND;
4019 break;
4020 case ARRAY:
4021 boundkind |= kinds[i] = ARRAY_BOUND;
4022 break;
4023 case TYPEVAR:
4024 do {
4025 t = t.getUpperBound();
4026 } while (t.hasTag(TYPEVAR));
4027 if (t.hasTag(ARRAY)) {
4028 boundkind |= kinds[i] = ARRAY_BOUND;
4029 } else {
4030 boundkind |= kinds[i] = CLASS_BOUND;
4031 }
4032 break;
4033 default:
4034 kinds[i] = UNKNOWN_BOUND;
4035 if (t.isPrimitive())
4036 return syms.errType;
4037 }
4038 }
4039 switch (boundkind) {
4040 case 0:
4041 return syms.botType;
4042
4043 case ARRAY_BOUND:
4044 // calculate lub(A[], B[])
4045 Type[] elements = new Type[ts.length];
4046 for (int i = 0 ; i < ts.length ; i++) {
4047 Type elem = elements[i] = elemTypeFun.apply(ts[i]);
4048 if (elem.isPrimitive()) {
4049 // if a primitive type is found, then return
4050 // arraySuperType unless all the types are the
4051 // same
4052 Type first = ts[0];
4053 for (int j = 1 ; j < ts.length ; j++) {
4054 if (!isSameType(first, ts[j])) {
4055 // lub(int[], B[]) is Cloneable & Serializable
4056 return arraySuperType();
4057 }
4058 }
4059 // all the array types are the same, return one
4060 // lub(int[], int[]) is int[]
4061 return first;
4062 }
4063 }
4064 // lub(A[], B[]) is lub(A, B)[]
4065 return new ArrayType(lub(elements), syms.arrayClass);
4066
4067 case CLASS_BOUND:
4068 // calculate lub(A, B)
4069 int startIdx = 0;
4070 for (int i = 0; i < ts.length ; i++) {
4071 Type t = ts[i];
4072 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) {
4073 break;
4074 } else {
4075 startIdx++;
4076 }
4077 }
4078 Assert.check(startIdx < ts.length);
4079 //step 1 - compute erased candidate set (EC)
4080 List<Type> cl = erasedSupertypes(ts[startIdx]);
4081 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4082 Type t = ts[i];
4083 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
4084 cl = intersect(cl, erasedSupertypes(t));
4085 }
4086 //step 2 - compute minimal erased candidate set (MEC)
4087 List<Type> mec = closureMin(cl);
4088 //step 3 - for each element G in MEC, compute lci(Inv(G))
4089 List<Type> candidates = List.nil();
4090 for (Type erasedSupertype : mec) {
4091 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
4092 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4093 Type superType = asSuper(ts[i], erasedSupertype.tsym);
4094 lci = intersect(lci, superType != null ? List.of(superType) : List.nil());
4095 }
4096 candidates = candidates.appendList(lci);
4097 }
4098 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
4099 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
4100 return compoundMin(candidates);
4101
4102 default:
4103 // calculate lub(A, B[])
4104 List<Type> classes = List.of(arraySuperType());
4105 for (int i = 0 ; i < ts.length ; i++) {
4106 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays
4107 classes = classes.prepend(ts[i]);
4108 }
4109 // lub(A, B[]) is lub(A, arraySuperType)
4110 return lub(classes);
4111 }
4112 }
4113 // where
4114 List<Type> erasedSupertypes(Type t) {
4115 ListBuffer<Type> buf = new ListBuffer<>();
4116 for (Type sup : closure(t)) {
4117 if (sup.hasTag(TYPEVAR)) {
4118 buf.append(sup);
4119 } else {
4120 buf.append(erasure(sup));
4121 }
4122 }
4123 return buf.toList();
4124 }
4125
4126 private Type arraySuperType;
4127 private Type arraySuperType() {
4128 // initialized lazily to avoid problems during compiler startup
4129 if (arraySuperType == null) {
4130 // JLS 10.8: all arrays implement Cloneable and Serializable.
4131 arraySuperType = makeIntersectionType(List.of(syms.serializableType,
4132 syms.cloneableType), true);
4133 }
4134 return arraySuperType;
4135 }
4136 // </editor-fold>
4137
4138 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
4139 public Type glb(List<Type> ts) {
4140 Type t1 = ts.head;
4141 for (Type t2 : ts.tail) {
4142 if (t1.isErroneous())
4143 return t1;
4144 t1 = glb(t1, t2);
4145 }
4146 return t1;
4147 }
4148 //where
4149 public Type glb(Type t, Type s) {
4150 if (s == null)
4151 return t;
4152 else if (t.isPrimitive() || s.isPrimitive())
4153 return syms.errType;
4154 else if (isSubtypeNoCapture(t, s))
4155 return t;
4156 else if (isSubtypeNoCapture(s, t))
4157 return s;
4158
4159 List<Type> closure = union(closure(t), closure(s));
4160 return glbFlattened(closure, t);
4161 }
4162 //where
4163 /**
4164 * Perform glb for a list of non-primitive, non-error, non-compound types;
4165 * redundant elements are removed. Bounds should be ordered according to
4166 * {@link Symbol#precedes(TypeSymbol,Types)}.
4167 *
4168 * @param flatBounds List of type to glb
4169 * @param errT Original type to use if the result is an error type
4170 */
4171 private Type glbFlattened(List<Type> flatBounds, Type errT) {
4172 List<Type> bounds = closureMin(flatBounds);
4173
4174 if (bounds.isEmpty()) { // length == 0
4175 return syms.objectType;
4176 } else if (bounds.tail.isEmpty()) { // length == 1
4177 return bounds.head;
4178 } else { // length > 1
4179 int classCount = 0;
4180 List<Type> cvars = List.nil();
4181 List<Type> lowers = List.nil();
4182 for (Type bound : bounds) {
4183 if (!bound.isInterface()) {
4184 classCount++;
4185 Type lower = cvarLowerBound(bound);
4186 if (bound != lower && !lower.hasTag(BOT)) {
4187 cvars = cvars.append(bound);
4188 lowers = lowers.append(lower);
4189 }
4190 }
4191 }
4192 if (classCount > 1) {
4193 if (lowers.isEmpty()) {
4194 return createErrorType(errT);
4195 } else {
4196 // try again with lower bounds included instead of capture variables
4197 List<Type> newBounds = bounds.diff(cvars).appendList(lowers);
4198 return glb(newBounds);
4199 }
4200 }
4201 }
4202 return makeIntersectionType(bounds);
4203 }
4204 // </editor-fold>
4205
4206 // <editor-fold defaultstate="collapsed" desc="hashCode">
4207 /**
4208 * Compute a hash code on a type.
4209 */
4210 public int hashCode(Type t) {
4211 return hashCode(t, false);
4212 }
4213
4214 public int hashCode(Type t, boolean strict) {
4215 return strict ?
4216 hashCodeStrictVisitor.visit(t) :
4217 hashCodeVisitor.visit(t);
4218 }
4219 // where
4220 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor();
4221 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() {
4222 @Override
4223 public Integer visitTypeVar(TypeVar t, Void ignored) {
4224 return System.identityHashCode(t);
4225 }
4226 };
4227
4228 private static class HashCodeVisitor extends UnaryVisitor<Integer> {
4229 public Integer visitType(Type t, Void ignored) {
4230 return t.getTag().ordinal();
4231 }
4232
4233 @Override
4234 public Integer visitClassType(ClassType t, Void ignored) {
4235 int result = visit(t.getEnclosingType());
4236 result *= 127;
4237 result += t.tsym.flatName().hashCode();
4238 for (Type s : t.getTypeArguments()) {
4239 result *= 127;
4240 result += visit(s);
4241 }
4242 return result;
4243 }
4244
4245 @Override
4246 public Integer visitMethodType(MethodType t, Void ignored) {
4247 int h = METHOD.ordinal();
4248 for (List<Type> thisargs = t.argtypes;
4249 thisargs.tail != null;
4250 thisargs = thisargs.tail)
4251 h = (h << 5) + visit(thisargs.head);
4252 return (h << 5) + visit(t.restype);
4253 }
4254
4255 @Override
4256 public Integer visitWildcardType(WildcardType t, Void ignored) {
4257 int result = t.kind.hashCode();
4258 if (t.type != null) {
4259 result *= 127;
4260 result += visit(t.type);
4261 }
4262 return result;
4263 }
4264
4265 @Override
4266 public Integer visitArrayType(ArrayType t, Void ignored) {
4267 return visit(t.elemtype) + 12;
4268 }
4269
4270 @Override
4271 public Integer visitTypeVar(TypeVar t, Void ignored) {
4272 return System.identityHashCode(t);
4273 }
4274
4275 @Override
4276 public Integer visitUndetVar(UndetVar t, Void ignored) {
4277 return System.identityHashCode(t);
4278 }
4279
4280 @Override
4281 public Integer visitErrorType(ErrorType t, Void ignored) {
4282 return 0;
4283 }
4284 }
4285 // </editor-fold>
4286
4287 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
4288 /**
4289 * Does t have a result that is a subtype of the result type of s,
4290 * suitable for covariant returns? It is assumed that both types
4291 * are (possibly polymorphic) method types. Monomorphic method
4292 * types are handled in the obvious way. Polymorphic method types
4293 * require renaming all type variables of one to corresponding
4294 * type variables in the other, where correspondence is by
4295 * position in the type parameter list. */
4296 public boolean resultSubtype(Type t, Type s, Warner warner) {
4297 List<Type> tvars = t.getTypeArguments();
4298 List<Type> svars = s.getTypeArguments();
4299 Type tres = t.getReturnType();
4300 Type sres = subst(s.getReturnType(), svars, tvars);
4301 return covariantReturnType(tres, sres, warner);
4302 }
4303
4304 /**
4305 * Return-Type-Substitutable.
4306 * @jls 8.4.5 Method Result
4307 */
4308 public boolean returnTypeSubstitutable(Type r1, Type r2) {
4309 if (hasSameArgs(r1, r2))
4310 return resultSubtype(r1, r2, noWarnings);
4311 else
4312 return covariantReturnType(r1.getReturnType(),
4313 erasure(r2.getReturnType()),
4314 noWarnings);
4315 }
4316
4317 public boolean returnTypeSubstitutable(Type r1,
4318 Type r2, Type r2res,
4319 Warner warner) {
4320 if (isSameType(r1.getReturnType(), r2res))
4321 return true;
4322 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
4323 return false;
4324
4325 if (hasSameArgs(r1, r2))
4326 return covariantReturnType(r1.getReturnType(), r2res, warner);
4327 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
4328 return true;
4329 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
4330 return false;
4331 warner.warn(LintCategory.UNCHECKED);
4332 return true;
4333 }
4334
4335 /**
4336 * Is t an appropriate return type in an overrider for a
4337 * method that returns s?
4338 */
4339 public boolean covariantReturnType(Type t, Type s, Warner warner) {
4340 return
4341 isSameType(t, s) ||
4342 !t.isPrimitive() &&
4343 !s.isPrimitive() &&
4344 isAssignable(t, s, warner);
4345 }
4346 // </editor-fold>
4347
4348 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
4349 /**
4350 * Return the class that boxes the given primitive.
4351 */
4352 public ClassSymbol boxedClass(Type t) {
4353 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]);
4354 }
4355
4356 /**
4357 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
4358 */
4359 public Type boxedTypeOrType(Type t) {
4360 return t.isPrimitive() ?
4361 boxedClass(t).type :
4362 t;
4363 }
4364
4365 /**
4366 * Return the primitive type corresponding to a boxed type.
4367 */
4368 public Type unboxedType(Type t) {
4369 if (t.hasTag(ERROR))
4370 return Type.noType;
4371 for (int i=0; i<syms.boxedName.length; i++) {
4372 Name box = syms.boxedName[i];
4373 if (box != null &&
4374 asSuper(t, syms.enterClass(syms.java_base, box)) != null)
4375 return syms.typeOfTag[i];
4376 }
4377 return Type.noType;
4378 }
4379
4380 /**
4381 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
4382 */
4383 public Type unboxedTypeOrType(Type t) {
4384 Type unboxedType = unboxedType(t);
4385 return unboxedType.hasTag(NONE) ? t : unboxedType;
4386 }
4387 // </editor-fold>
4388
4389 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
4390 /*
4391 * JLS 5.1.10 Capture Conversion:
4392 *
4393 * Let G name a generic type declaration with n formal type
4394 * parameters A1 ... An with corresponding bounds U1 ... Un. There
4395 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
4396 * where, for 1 <= i <= n:
4397 *
4398 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
4399 * Si is a fresh type variable whose upper bound is
4400 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
4401 * type.
4402 *
4403 * + If Ti is a wildcard type argument of the form ? extends Bi,
4404 * then Si is a fresh type variable whose upper bound is
4405 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
4406 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
4407 * a compile-time error if for any two classes (not interfaces)
4408 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
4409 *
4410 * + If Ti is a wildcard type argument of the form ? super Bi,
4411 * then Si is a fresh type variable whose upper bound is
4412 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
4413 *
4414 * + Otherwise, Si = Ti.
4415 *
4416 * Capture conversion on any type other than a parameterized type
4417 * (4.5) acts as an identity conversion (5.1.1). Capture
4418 * conversions never require a special action at run time and
4419 * therefore never throw an exception at run time.
4420 *
4421 * Capture conversion is not applied recursively.
4422 */
4423 /**
4424 * Capture conversion as specified by the JLS.
4425 */
4426
4427 public List<Type> capture(List<Type> ts) {
4428 List<Type> buf = List.nil();
4429 for (Type t : ts) {
4430 buf = buf.prepend(capture(t));
4431 }
4432 return buf.reverse();
4433 }
4434
4435 public Type capture(Type t) {
4436 if (!t.hasTag(CLASS)) {
4437 return t;
4438 }
4439 if (t.getEnclosingType() != Type.noType) {
4440 Type capturedEncl = capture(t.getEnclosingType());
4441 if (capturedEncl != t.getEnclosingType()) {
4442 Type type1 = memberType(capturedEncl, t.tsym);
4443 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
4444 }
4445 }
4446 ClassType cls = (ClassType)t;
4447 if (cls.isRaw() || !cls.isParameterized())
4448 return cls;
4449
4450 ClassType G = (ClassType)cls.asElement().asType();
4451 List<Type> A = G.getTypeArguments();
4452 List<Type> T = cls.getTypeArguments();
4453 List<Type> S = freshTypeVariables(T);
4454
4455 List<Type> currentA = A;
4456 List<Type> currentT = T;
4457 List<Type> currentS = S;
4458 boolean captured = false;
4459 while (!currentA.isEmpty() &&
4460 !currentT.isEmpty() &&
4461 !currentS.isEmpty()) {
4462 if (currentS.head != currentT.head) {
4463 captured = true;
4464 WildcardType Ti = (WildcardType)currentT.head;
4465 Type Ui = currentA.head.getUpperBound();
4466 CapturedType Si = (CapturedType)currentS.head;
4467 if (Ui == null)
4468 Ui = syms.objectType;
4469 switch (Ti.kind) {
4470 case UNBOUND:
4471 Si.setUpperBound( subst(Ui, A, S) );
4472 Si.lower = syms.botType;
4473 break;
4474 case EXTENDS:
4475 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) );
4476 Si.lower = syms.botType;
4477 break;
4478 case SUPER:
4479 Si.setUpperBound( subst(Ui, A, S) );
4480 Si.lower = Ti.getSuperBound();
4481 break;
4482 }
4483 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound();
4484 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower;
4485 if (!Si.getUpperBound().hasTag(ERROR) &&
4486 !Si.lower.hasTag(ERROR) &&
4487 isSameType(tmpBound, tmpLower)) {
4488 currentS.head = Si.getUpperBound();
4489 }
4490 }
4491 currentA = currentA.tail;
4492 currentT = currentT.tail;
4493 currentS = currentS.tail;
4494 }
4495 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
4496 return erasure(t); // some "rare" type involved
4497
4498 if (captured)
4499 return new ClassType(cls.getEnclosingType(), S, cls.tsym,
4500 cls.getMetadata());
4501 else
4502 return t;
4503 }
4504 // where
4505 public List<Type> freshTypeVariables(List<Type> types) {
4506 ListBuffer<Type> result = new ListBuffer<>();
4507 for (Type t : types) {
4508 if (t.hasTag(WILDCARD)) {
4509 Type bound = ((WildcardType)t).getExtendsBound();
4510 if (bound == null)
4511 bound = syms.objectType;
4512 result.append(new CapturedType(capturedName,
4513 syms.noSymbol,
4514 bound,
4515 syms.botType,
4516 (WildcardType)t));
4517 } else {
4518 result.append(t);
4519 }
4520 }
4521 return result.toList();
4522 }
4523 // </editor-fold>
4524
4525 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
4526 private boolean sideCast(Type from, Type to, Warner warn) {
4527 // We are casting from type $from$ to type $to$, which are
4528 // non-final unrelated types. This method
4529 // tries to reject a cast by transferring type parameters
4530 // from $to$ to $from$ by common superinterfaces.
4531 boolean reverse = false;
4532 Type target = to;
4533 if ((to.tsym.flags() & INTERFACE) == 0) {
4534 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4535 reverse = true;
4536 to = from;
4537 from = target;
4538 }
4539 List<Type> commonSupers = superClosure(to, erasure(from));
4540 boolean giveWarning = commonSupers.isEmpty();
4541 // The arguments to the supers could be unified here to
4542 // get a more accurate analysis
4543 while (commonSupers.nonEmpty()) {
4544 Type t1 = asSuper(from, commonSupers.head.tsym);
4545 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
4546 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4547 return false;
4548 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
4549 commonSupers = commonSupers.tail;
4550 }
4551 if (giveWarning && !isReifiable(reverse ? from : to))
4552 warn.warn(LintCategory.UNCHECKED);
4553 return true;
4554 }
4555
4556 private boolean sideCastFinal(Type from, Type to, Warner warn) {
4557 // We are casting from type $from$ to type $to$, which are
4558 // unrelated types one of which is final and the other of
4559 // which is an interface. This method
4560 // tries to reject a cast by transferring type parameters
4561 // from the final class to the interface.
4562 boolean reverse = false;
4563 Type target = to;
4564 if ((to.tsym.flags() & INTERFACE) == 0) {
4565 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4566 reverse = true;
4567 to = from;
4568 from = target;
4569 }
4570 Assert.check((from.tsym.flags() & FINAL) != 0);
4571 Type t1 = asSuper(from, to.tsym);
4572 if (t1 == null) return false;
4573 Type t2 = to;
4574 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4575 return false;
4576 if (!isReifiable(target) &&
4577 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
4578 warn.warn(LintCategory.UNCHECKED);
4579 return true;
4580 }
4581
4582 private boolean giveWarning(Type from, Type to) {
4583 List<Type> bounds = to.isCompound() ?
4584 directSupertypes(to) : List.of(to);
4585 for (Type b : bounds) {
4586 Type subFrom = asSub(from, b.tsym);
4587 if (b.isParameterized() &&
4588 (!(isUnbounded(b) ||
4589 isSubtype(from, b) ||
4590 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
4591 return true;
4592 }
4593 }
4594 return false;
4595 }
4596
4597 private List<Type> superClosure(Type t, Type s) {
4598 List<Type> cl = List.nil();
4599 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
4600 if (isSubtype(s, erasure(l.head))) {
4601 cl = insert(cl, l.head);
4602 } else {
4603 cl = union(cl, superClosure(l.head, s));
4604 }
4605 }
4606 return cl;
4607 }
4608
4609 private boolean containsTypeEquivalent(Type t, Type s) {
4610 return isSameType(t, s) || // shortcut
4611 containsType(t, s) && containsType(s, t);
4612 }
4613
4614 // <editor-fold defaultstate="collapsed" desc="adapt">
4615 /**
4616 * Adapt a type by computing a substitution which maps a source
4617 * type to a target type.
4618 *
4619 * @param source the source type
4620 * @param target the target type
4621 * @param from the type variables of the computed substitution
4622 * @param to the types of the computed substitution.
4623 */
4624 public void adapt(Type source,
4625 Type target,
4626 ListBuffer<Type> from,
4627 ListBuffer<Type> to) throws AdaptFailure {
4628 new Adapter(from, to).adapt(source, target);
4629 }
4630
4631 class Adapter extends SimpleVisitor<Void, Type> {
4632
4633 ListBuffer<Type> from;
4634 ListBuffer<Type> to;
4635 Map<Symbol,Type> mapping;
4636
4637 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
4638 this.from = from;
4639 this.to = to;
4640 mapping = new HashMap<>();
4641 }
4642
4643 public void adapt(Type source, Type target) throws AdaptFailure {
4644 visit(source, target);
4645 List<Type> fromList = from.toList();
4646 List<Type> toList = to.toList();
4647 while (!fromList.isEmpty()) {
4648 Type val = mapping.get(fromList.head.tsym);
4649 if (toList.head != val)
4650 toList.head = val;
4651 fromList = fromList.tail;
4652 toList = toList.tail;
4653 }
4654 }
4655
4656 @Override
4657 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
4658 if (target.hasTag(CLASS))
4659 adaptRecursive(source.allparams(), target.allparams());
4660 return null;
4661 }
4662
4663 @Override
4664 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
4665 if (target.hasTag(ARRAY))
4666 adaptRecursive(elemtype(source), elemtype(target));
4667 return null;
4668 }
4669
4670 @Override
4671 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
4672 if (source.isExtendsBound())
4673 adaptRecursive(wildUpperBound(source), wildUpperBound(target));
4674 else if (source.isSuperBound())
4675 adaptRecursive(wildLowerBound(source), wildLowerBound(target));
4676 return null;
4677 }
4678
4679 @Override
4680 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
4681 // Check to see if there is
4682 // already a mapping for $source$, in which case
4683 // the old mapping will be merged with the new
4684 Type val = mapping.get(source.tsym);
4685 if (val != null) {
4686 if (val.isSuperBound() && target.isSuperBound()) {
4687 val = isSubtype(wildLowerBound(val), wildLowerBound(target))
4688 ? target : val;
4689 } else if (val.isExtendsBound() && target.isExtendsBound()) {
4690 val = isSubtype(wildUpperBound(val), wildUpperBound(target))
4691 ? val : target;
4692 } else if (!isSameType(val, target)) {
4693 throw new AdaptFailure();
4694 }
4695 } else {
4696 val = target;
4697 from.append(source);
4698 to.append(target);
4699 }
4700 mapping.put(source.tsym, val);
4701 return null;
4702 }
4703
4704 @Override
4705 public Void visitType(Type source, Type target) {
4706 return null;
4707 }
4708
4709 private Set<TypePair> cache = new HashSet<>();
4710
4711 private void adaptRecursive(Type source, Type target) {
4712 TypePair pair = new TypePair(source, target);
4713 if (cache.add(pair)) {
4714 try {
4715 visit(source, target);
4716 } finally {
4717 cache.remove(pair);
4718 }
4719 }
4720 }
4721
4722 private void adaptRecursive(List<Type> source, List<Type> target) {
4723 if (source.length() == target.length()) {
4724 while (source.nonEmpty()) {
4725 adaptRecursive(source.head, target.head);
4726 source = source.tail;
4727 target = target.tail;
4728 }
4729 }
4730 }
4731 }
4732
4733 public static class AdaptFailure extends RuntimeException {
4734 static final long serialVersionUID = -7490231548272701566L;
4735 }
4736
4737 private void adaptSelf(Type t,
4738 ListBuffer<Type> from,
4739 ListBuffer<Type> to) {
4740 try {
4741 //if (t.tsym.type != t)
4742 adapt(t.tsym.type, t, from, to);
4743 } catch (AdaptFailure ex) {
4744 // Adapt should never fail calculating a mapping from
4745 // t.tsym.type to t as there can be no merge problem.
4746 throw new AssertionError(ex);
4747 }
4748 }
4749 // </editor-fold>
4750
4751 /**
4752 * Rewrite all type variables (universal quantifiers) in the given
4753 * type to wildcards (existential quantifiers). This is used to
4754 * determine if a cast is allowed. For example, if high is true
4755 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4756 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4757 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4758 * List<Integer>} with a warning.
4759 * @param t a type
4760 * @param high if true return an upper bound; otherwise a lower
4761 * bound
4762 * @param rewriteTypeVars only rewrite captured wildcards if false;
4763 * otherwise rewrite all type variables
4764 * @return the type rewritten with wildcards (existential
4765 * quantifiers) only
4766 */
4767 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4768 return new Rewriter(high, rewriteTypeVars).visit(t);
4769 }
4770
4771 class Rewriter extends UnaryVisitor<Type> {
4772
4773 boolean high;
4774 boolean rewriteTypeVars;
4775
4776 Rewriter(boolean high, boolean rewriteTypeVars) {
4777 this.high = high;
4778 this.rewriteTypeVars = rewriteTypeVars;
4779 }
4780
4781 @Override
4782 public Type visitClassType(ClassType t, Void s) {
4783 ListBuffer<Type> rewritten = new ListBuffer<>();
4784 boolean changed = false;
4785 for (Type arg : t.allparams()) {
4786 Type bound = visit(arg);
4787 if (arg != bound) {
4788 changed = true;
4789 }
4790 rewritten.append(bound);
4791 }
4792 if (changed)
4793 return subst(t.tsym.type,
4794 t.tsym.type.allparams(),
4795 rewritten.toList());
4796 else
4797 return t;
4798 }
4799
4800 public Type visitType(Type t, Void s) {
4801 return t;
4802 }
4803
4804 @Override
4805 public Type visitCapturedType(CapturedType t, Void s) {
4806 Type w_bound = t.wildcard.type;
4807 Type bound = w_bound.contains(t) ?
4808 erasure(w_bound) :
4809 visit(w_bound);
4810 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4811 }
4812
4813 @Override
4814 public Type visitTypeVar(TypeVar t, Void s) {
4815 if (rewriteTypeVars) {
4816 Type bound = t.getUpperBound().contains(t) ?
4817 erasure(t.getUpperBound()) :
4818 visit(t.getUpperBound());
4819 return rewriteAsWildcardType(bound, t, EXTENDS);
4820 } else {
4821 return t;
4822 }
4823 }
4824
4825 @Override
4826 public Type visitWildcardType(WildcardType t, Void s) {
4827 Type bound2 = visit(t.type);
4828 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4829 }
4830
4831 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4832 switch (bk) {
4833 case EXTENDS: return high ?
4834 makeExtendsWildcard(B(bound), formal) :
4835 makeExtendsWildcard(syms.objectType, formal);
4836 case SUPER: return high ?
4837 makeSuperWildcard(syms.botType, formal) :
4838 makeSuperWildcard(B(bound), formal);
4839 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4840 default:
4841 Assert.error("Invalid bound kind " + bk);
4842 return null;
4843 }
4844 }
4845
4846 Type B(Type t) {
4847 while (t.hasTag(WILDCARD)) {
4848 WildcardType w = (WildcardType)t;
4849 t = high ?
4850 w.getExtendsBound() :
4851 w.getSuperBound();
4852 if (t == null) {
4853 t = high ? syms.objectType : syms.botType;
4854 }
4855 }
4856 return t;
4857 }
4858 }
4859
4860
4861 /**
4862 * Create a wildcard with the given upper (extends) bound; create
4863 * an unbounded wildcard if bound is Object.
4864 *
4865 * @param bound the upper bound
4866 * @param formal the formal type parameter that will be
4867 * substituted by the wildcard
4868 */
4869 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4870 if (bound == syms.objectType) {
4871 return new WildcardType(syms.objectType,
4872 BoundKind.UNBOUND,
4873 syms.boundClass,
4874 formal);
4875 } else {
4876 return new WildcardType(bound,
4877 BoundKind.EXTENDS,
4878 syms.boundClass,
4879 formal);
4880 }
4881 }
4882
4883 /**
4884 * Create a wildcard with the given lower (super) bound; create an
4885 * unbounded wildcard if bound is bottom (type of {@code null}).
4886 *
4887 * @param bound the lower bound
4888 * @param formal the formal type parameter that will be
4889 * substituted by the wildcard
4890 */
4891 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4892 if (bound.hasTag(BOT)) {
4893 return new WildcardType(syms.objectType,
4894 BoundKind.UNBOUND,
4895 syms.boundClass,
4896 formal);
4897 } else {
4898 return new WildcardType(bound,
4899 BoundKind.SUPER,
4900 syms.boundClass,
4901 formal);
4902 }
4903 }
4904
4905 /**
4906 * A wrapper for a type that allows use in sets.
4907 */
4908 public static class UniqueType {
4909 public final Type type;
4910 final Types types;
4911
4912 public UniqueType(Type type, Types types) {
4913 this.type = type;
4914 this.types = types;
4915 }
4916
4917 public int hashCode() {
4918 return types.hashCode(type);
4919 }
4920
4921 public boolean equals(Object obj) {
4922 return (obj instanceof UniqueType uniqueType) &&
4923 types.isSameType(type, uniqueType.type);
4924 }
4925
4926 public String toString() {
4927 return type.toString();
4928 }
4929
4930 }
4931 // </editor-fold>
4932
4933 // <editor-fold defaultstate="collapsed" desc="Visitors">
4934 /**
4935 * A default visitor for types. All visitor methods except
4936 * visitType are implemented by delegating to visitType. Concrete
4937 * subclasses must provide an implementation of visitType and can
4938 * override other methods as needed.
4939 *
4940 * @param <R> the return type of the operation implemented by this
4941 * visitor; use Void if no return type is needed.
4942 * @param <S> the type of the second argument (the first being the
4943 * type itself) of the operation implemented by this visitor; use
4944 * Void if a second argument is not needed.
4945 */
4946 public abstract static class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4947 public final R visit(Type t, S s) { return t.accept(this, s); }
4948 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4949 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4950 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4951 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4952 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4953 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); }
4954 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4955 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4956 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4957 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4958 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4959 }
4960
4961 /**
4962 * A default visitor for symbols. All visitor methods except
4963 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4964 * subclasses must provide an implementation of visitSymbol and can
4965 * override other methods as needed.
4966 *
4967 * @param <R> the return type of the operation implemented by this
4968 * visitor; use Void if no return type is needed.
4969 * @param <S> the type of the second argument (the first being the
4970 * symbol itself) of the operation implemented by this visitor; use
4971 * Void if a second argument is not needed.
4972 */
4973 public abstract static class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4974 public final R visit(Symbol s, S arg) { return s.accept(this, arg); }
4975 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4976 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4977 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4978 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4979 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4980 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4981 }
4982
4983 /**
4984 * A <em>simple</em> visitor for types. This visitor is simple as
4985 * captured wildcards, for-all types (generic methods), and
4986 * undetermined type variables (part of inference) are hidden.
4987 * Captured wildcards are hidden by treating them as type
4988 * variables and the rest are hidden by visiting their qtypes.
4989 *
4990 * @param <R> the return type of the operation implemented by this
4991 * visitor; use Void if no return type is needed.
4992 * @param <S> the type of the second argument (the first being the
4993 * type itself) of the operation implemented by this visitor; use
4994 * Void if a second argument is not needed.
4995 */
4996 public abstract static class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4997 @Override
4998 public R visitCapturedType(CapturedType t, S s) {
4999 return visitTypeVar(t, s);
5000 }
5001 @Override
5002 public R visitForAll(ForAll t, S s) {
5003 return visit(t.qtype, s);
5004 }
5005 @Override
5006 public R visitUndetVar(UndetVar t, S s) {
5007 return visit(t.qtype, s);
5008 }
5009 }
5010
5011 /**
5012 * A plain relation on types. That is a 2-ary function on the
5013 * form Type × Type → Boolean.
5014 * <!-- In plain text: Type x Type -> Boolean -->
5015 */
5016 public abstract static class TypeRelation extends SimpleVisitor<Boolean,Type> {}
5017
5018 /**
5019 * A convenience visitor for implementing operations that only
5020 * require one argument (the type itself), that is, unary
5021 * operations.
5022 *
5023 * @param <R> the return type of the operation implemented by this
5024 * visitor; use Void if no return type is needed.
5025 */
5026 public abstract static class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
5027 public final R visit(Type t) { return t.accept(this, null); }
5028 }
5029
5030 /**
5031 * A visitor for implementing a mapping from types to types. The
5032 * default behavior of this class is to implement the identity
5033 * mapping (mapping a type to itself). This can be overridden in
5034 * subclasses.
5035 *
5036 * @param <S> the type of the second argument (the first being the
5037 * type itself) of this mapping; use Void if a second argument is
5038 * not needed.
5039 */
5040 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
5041 public final Type visit(Type t) { return t.accept(this, null); }
5042 public Type visitType(Type t, S s) { return t; }
5043 }
5044
5045 /**
5046 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}.
5047 * This class implements the functional interface {@code Function}, that allows it to be used
5048 * fluently in stream-like processing.
5049 */
5050 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> {
5051 @Override
5052 public Type apply(Type type) { return visit(type); }
5053
5054 List<Type> visit(List<Type> ts, S s) {
5055 return ts.map(t -> visit(t, s));
5056 }
5057
5058 @Override
5059 public Type visitCapturedType(CapturedType t, S s) {
5060 return visitTypeVar(t, s);
5061 }
5062 }
5063 // </editor-fold>
5064
5065
5066 // <editor-fold defaultstate="collapsed" desc="Annotation support">
5067
5068 public RetentionPolicy getRetention(Attribute.Compound a) {
5069 return getRetention(a.type.tsym);
5070 }
5071
5072 public RetentionPolicy getRetention(TypeSymbol sym) {
5073 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
5074 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
5075 if (c != null) {
5076 Attribute value = c.member(names.value);
5077 if (value != null && value instanceof Attribute.Enum attributeEnum) {
5078 Name levelName = attributeEnum.value.name;
5079 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
5080 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
5081 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
5082 else ;// /* fail soft */ throw new AssertionError(levelName);
5083 }
5084 }
5085 return vis;
5086 }
5087 // </editor-fold>
5088
5089 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
5090
5091 public abstract static class SignatureGenerator {
5092
5093 public static class InvalidSignatureException extends RuntimeException {
5094 private static final long serialVersionUID = 0;
5095
5096 private final transient Type type;
5097
5098 InvalidSignatureException(Type type) {
5099 this.type = type;
5100 }
5101
5102 public Type type() {
5103 return type;
5104 }
5105
5106 @Override
5107 public Throwable fillInStackTrace() {
5108 // This is an internal exception; the stack trace is irrelevant.
5109 return this;
5110 }
5111 }
5112
5113 private final Types types;
5114
5115 protected abstract void append(char ch);
5116 protected abstract void append(byte[] ba);
5117 protected abstract void append(Name name);
5118 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
5119
5120 protected SignatureGenerator(Types types) {
5121 this.types = types;
5122 }
5123
5124 protected void reportIllegalSignature(Type t) {
5125 throw new InvalidSignatureException(t);
5126 }
5127
5128 /**
5129 * Assemble signature of given type in string buffer.
5130 */
5131 public void assembleSig(Type type) {
5132 switch (type.getTag()) {
5133 case BYTE:
5134 append('B');
5135 break;
5136 case SHORT:
5137 append('S');
5138 break;
5139 case CHAR:
5140 append('C');
5141 break;
5142 case INT:
5143 append('I');
5144 break;
5145 case LONG:
5146 append('J');
5147 break;
5148 case FLOAT:
5149 append('F');
5150 break;
5151 case DOUBLE:
5152 append('D');
5153 break;
5154 case BOOLEAN:
5155 append('Z');
5156 break;
5157 case VOID:
5158 append('V');
5159 break;
5160 case CLASS:
5161 if (type.isCompound()) {
5162 reportIllegalSignature(type);
5163 }
5164 append('L');
5165 assembleClassSig(type);
5166 append(';');
5167 break;
5168 case ARRAY:
5169 ArrayType at = (ArrayType) type;
5170 append('[');
5171 assembleSig(at.elemtype);
5172 break;
5173 case METHOD:
5174 MethodType mt = (MethodType) type;
5175 append('(');
5176 assembleSig(mt.argtypes);
5177 append(')');
5178 assembleSig(mt.restype);
5179 if (hasTypeVar(mt.thrown)) {
5180 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
5181 append('^');
5182 assembleSig(l.head);
5183 }
5184 }
5185 break;
5186 case WILDCARD: {
5187 Type.WildcardType ta = (Type.WildcardType) type;
5188 switch (ta.kind) {
5189 case SUPER:
5190 append('-');
5191 assembleSig(ta.type);
5192 break;
5193 case EXTENDS:
5194 append('+');
5195 assembleSig(ta.type);
5196 break;
5197 case UNBOUND:
5198 append('*');
5199 break;
5200 default:
5201 throw new AssertionError(ta.kind);
5202 }
5203 break;
5204 }
5205 case TYPEVAR:
5206 if (((TypeVar)type).isCaptured()) {
5207 reportIllegalSignature(type);
5208 }
5209 append('T');
5210 append(type.tsym.name);
5211 append(';');
5212 break;
5213 case FORALL:
5214 Type.ForAll ft = (Type.ForAll) type;
5215 assembleParamsSig(ft.tvars);
5216 assembleSig(ft.qtype);
5217 break;
5218 default:
5219 throw new AssertionError("typeSig " + type.getTag());
5220 }
5221 }
5222
5223 public boolean hasTypeVar(List<Type> l) {
5224 while (l.nonEmpty()) {
5225 if (l.head.hasTag(TypeTag.TYPEVAR)) {
5226 return true;
5227 }
5228 l = l.tail;
5229 }
5230 return false;
5231 }
5232
5233 public void assembleClassSig(Type type) {
5234 ClassType ct = (ClassType) type;
5235 ClassSymbol c = (ClassSymbol) ct.tsym;
5236 classReference(c);
5237 Type outer = ct.getEnclosingType();
5238 if (outer.allparams().nonEmpty()) {
5239 boolean rawOuter =
5240 c.owner.kind == MTH || // either a local class
5241 c.name == types.names.empty; // or anonymous
5242 assembleClassSig(rawOuter
5243 ? types.erasure(outer)
5244 : outer);
5245 append(rawOuter ? '$' : '.');
5246 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
5247 append(rawOuter
5248 ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength())
5249 : c.name);
5250 } else {
5251 append(externalize(c.flatname));
5252 }
5253 if (ct.getTypeArguments().nonEmpty()) {
5254 append('<');
5255 assembleSig(ct.getTypeArguments());
5256 append('>');
5257 }
5258 }
5259
5260 public void assembleParamsSig(List<Type> typarams) {
5261 append('<');
5262 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
5263 Type.TypeVar tvar = (Type.TypeVar) ts.head;
5264 append(tvar.tsym.name);
5265 List<Type> bounds = types.getBounds(tvar);
5266 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
5267 append(':');
5268 }
5269 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
5270 append(':');
5271 assembleSig(l.head);
5272 }
5273 }
5274 append('>');
5275 }
5276
5277 public void assembleSig(List<Type> types) {
5278 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
5279 assembleSig(ts.head);
5280 }
5281 }
5282 }
5283
5284 public Type constantType(LoadableConstant c) {
5285 switch (c.poolTag()) {
5286 case ClassFile.CONSTANT_Class:
5287 return syms.classType;
5288 case ClassFile.CONSTANT_String:
5289 return syms.stringType;
5290 case ClassFile.CONSTANT_Integer:
5291 return syms.intType;
5292 case ClassFile.CONSTANT_Float:
5293 return syms.floatType;
5294 case ClassFile.CONSTANT_Long:
5295 return syms.longType;
5296 case ClassFile.CONSTANT_Double:
5297 return syms.doubleType;
5298 case ClassFile.CONSTANT_MethodHandle:
5299 return syms.methodHandleType;
5300 case ClassFile.CONSTANT_MethodType:
5301 return syms.methodTypeType;
5302 case ClassFile.CONSTANT_Dynamic:
5303 return ((DynamicVarSymbol)c).type;
5304 default:
5305 throw new AssertionError("Not a loadable constant: " + c.poolTag());
5306 }
5307 }
5308 // </editor-fold>
5309
5310 public void newRound() {
5311 descCache._map.clear();
5312 isDerivedRawCache.clear();
5313 implCache._map.clear();
5314 membersCache._map.clear();
5315 closureCache.clear();
5316 }
5317 }