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