1 /*
2 * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.tools.javac.code;
27
28 import java.lang.ref.SoftReference;
29 import java.util.HashSet;
30 import java.util.HashMap;
31 import java.util.Locale;
32 import java.util.Map;
33 import java.util.Optional;
34 import java.util.Set;
35 import java.util.WeakHashMap;
36 import java.util.function.BiPredicate;
37 import java.util.function.Function;
38 import java.util.function.Predicate;
39 import java.util.stream.Collector;
40
41 import javax.tools.JavaFileObject;
42
43 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
44 import com.sun.tools.javac.code.Lint.LintCategory;
45 import com.sun.tools.javac.code.Source.Feature;
46 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
47 import com.sun.tools.javac.code.TypeMetadata.Annotations;
48 import com.sun.tools.javac.comp.AttrContext;
49 import com.sun.tools.javac.comp.Check;
50 import com.sun.tools.javac.comp.Enter;
51 import com.sun.tools.javac.comp.Env;
52 import com.sun.tools.javac.comp.LambdaToMethod;
53 import com.sun.tools.javac.jvm.ClassFile;
54 import com.sun.tools.javac.util.*;
55
56 import static com.sun.tools.javac.code.BoundKind.*;
57 import static com.sun.tools.javac.code.Flags.*;
58 import static com.sun.tools.javac.code.Kinds.Kind.*;
59 import static com.sun.tools.javac.code.Scope.*;
60 import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
61 import static com.sun.tools.javac.code.Symbol.*;
62 import static com.sun.tools.javac.code.Type.*;
63 import static com.sun.tools.javac.code.TypeTag.*;
64 import static com.sun.tools.javac.jvm.ClassFile.externalize;
65 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
66
67 /**
68 * Utility class containing various operations on types.
69 *
70 * <p>Unless other names are more illustrative, the following naming
71 * conventions should be observed in this file:
72 *
73 * <dl>
74 * <dt>t</dt>
75 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
76 * <dt>s</dt>
77 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
78 * <dt>ts</dt>
79 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
80 * <dt>ss</dt>
81 * <dd>A second list of types should be named ss.</dd>
82 * </dl>
83 *
84 * <p><b>This is NOT part of any supported API.
85 * If you write code that depends on this, you do so at your own risk.
86 * This code and its internal interfaces are subject to change or
87 * deletion without notice.</b>
88 */
89 public class Types {
90 protected static final Context.Key<Types> typesKey = new Context.Key<>();
91
92 final Symtab syms;
93 final JavacMessages messages;
94 final Names names;
95 final Check chk;
96 final Enter enter;
97 JCDiagnostic.Factory diags;
98 List<Warner> warnStack = List.nil();
99 final Name capturedName;
100
101 public final Warner noWarnings;
102
103 // <editor-fold defaultstate="collapsed" desc="Instantiating">
104 public static Types instance(Context context) {
105 Types instance = context.get(typesKey);
106 if (instance == null)
107 instance = new Types(context);
108 return instance;
109 }
110
111 @SuppressWarnings("this-escape")
112 protected Types(Context context) {
113 context.put(typesKey, this);
114 syms = Symtab.instance(context);
115 names = Names.instance(context);
116 Source source = Source.instance(context);
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.getUpperBound();
136 else
137 return wildUpperBound(w.type);
138 }
139 else return t;
140 }
141
142 /**
143 * Get a capture variable's upper bound, returning other types unchanged.
144 * @param t a type
145 */
146 public Type cvarUpperBound(Type t) {
147 if (t.hasTag(TYPEVAR)) {
148 TypeVar v = (TypeVar) t;
149 return v.isCaptured() ? cvarUpperBound(v.getUpperBound()) : v;
150 }
151 else return t;
152 }
153
154 /**
155 * Get a wildcard's lower bound, returning non-wildcards unchanged.
156 * @param t a type argument, either a wildcard or a type
157 */
158 public Type wildLowerBound(Type t) {
159 if (t.hasTag(WILDCARD)) {
160 WildcardType w = (WildcardType) t;
161 return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type);
162 }
163 else return t;
164 }
165
166 /**
167 * Get a capture variable's lower bound, returning other types unchanged.
168 * @param t a type
169 */
170 public Type cvarLowerBound(Type t) {
171 if (t.hasTag(TYPEVAR) && ((TypeVar) t).isCaptured()) {
172 return cvarLowerBound(t.getLowerBound());
173 }
174 else return t;
175 }
176
177 /**
178 * Recursively skip type-variables until a class/array type is found; capture conversion is then
179 * (optionally) applied to the resulting type. This is useful for i.e. computing a site that is
180 * suitable for a method lookup.
181 */
182 public Type skipTypeVars(Type site, boolean capture) {
183 while (site.hasTag(TYPEVAR)) {
184 site = site.getUpperBound();
185 }
186 return capture ? capture(site) : site;
187 }
188 // </editor-fold>
189
190 // <editor-fold defaultstate="collapsed" desc="projections">
191
192 /**
193 * A projection kind. See {@link TypeProjection}
194 */
195 enum ProjectionKind {
196 UPWARDS() {
197 @Override
198 ProjectionKind complement() {
199 return DOWNWARDS;
200 }
201 },
202 DOWNWARDS() {
203 @Override
204 ProjectionKind complement() {
205 return UPWARDS;
206 }
207 };
208
209 abstract ProjectionKind complement();
210 }
211
212 /**
213 * This visitor performs upwards and downwards projections on types.
214 *
215 * A projection is defined as a function that takes a type T, a set of type variables V and that
216 * produces another type S.
217 *
218 * An upwards projection maps a type T into a type S such that (i) T has no variables in V,
219 * and (ii) S is an upper bound of T.
220 *
221 * A downwards projection maps a type T into a type S such that (i) T has no variables in V,
222 * and (ii) S is a lower bound of T.
223 *
224 * Note that projections are only allowed to touch variables in V. Therefore, it is possible for
225 * a projection to leave its input type unchanged if it does not contain any variables in V.
226 *
227 * Moreover, note that while an upwards projection is always defined (every type as an upper bound),
228 * a downwards projection is not always defined.
229 *
230 * Examples:
231 *
232 * {@code upwards(List<#CAP1>, [#CAP1]) = List<? extends String>, where #CAP1 <: String }
233 * {@code downwards(List<#CAP2>, [#CAP2]) = List<? super String>, where #CAP2 :> String }
234 * {@code upwards(List<#CAP1>, [#CAP2]) = List<#CAP1> }
235 * {@code downwards(List<#CAP1>, [#CAP1]) = not defined }
236 */
237 class TypeProjection extends TypeMapping<ProjectionKind> {
238
239 List<Type> vars;
240 Set<Type> seen = new HashSet<>();
241
242 public TypeProjection(List<Type> vars) {
243 this.vars = vars;
244 }
245
246 @Override
247 public Type visitClassType(ClassType t, ProjectionKind pkind) {
248 if (t.isCompound()) {
249 List<Type> components = directSupertypes(t);
250 List<Type> components1 = components.map(c -> c.map(this, pkind));
251 if (components == components1) return t;
252 else return makeIntersectionType(components1);
253 } else {
254 Type outer = t.getEnclosingType();
255 Type outer1 = visit(outer, pkind);
256 List<Type> typarams = t.getTypeArguments();
257 List<Type> formals = t.tsym.type.getTypeArguments();
258 ListBuffer<Type> typarams1 = new ListBuffer<>();
259 boolean changed = false;
260 for (Type actual : typarams) {
261 Type t2 = mapTypeArgument(t, formals.head.getUpperBound(), actual, pkind);
262 if (t2.hasTag(BOT)) {
263 //not defined
264 return syms.botType;
265 }
266 typarams1.add(t2);
267 changed |= actual != t2;
268 formals = formals.tail;
269 }
270 if (outer1 == outer && !changed) return t;
271 else return new ClassType(outer1, typarams1.toList(), t.tsym, t.getMetadata()) {
272 @Override
273 protected boolean needsStripping() {
274 return true;
275 }
276 };
277 }
278 }
279
280 @Override
281 public Type visitArrayType(ArrayType t, ProjectionKind s) {
282 Type elemtype = t.elemtype;
283 Type elemtype1 = visit(elemtype, s);
284 if (elemtype1 == elemtype) {
285 return t;
286 } else if (elemtype1.hasTag(BOT)) {
287 //undefined
288 return syms.botType;
289 } else {
290 return new ArrayType(elemtype1, t.tsym, t.metadata) {
291 @Override
292 protected boolean needsStripping() {
293 return true;
294 }
295 };
296 }
297 }
298
299 @Override
300 public Type visitTypeVar(TypeVar t, ProjectionKind pkind) {
301 if (vars.contains(t)) {
302 if (seen.add(t)) {
303 try {
304 final Type bound;
305 switch (pkind) {
306 case UPWARDS:
307 bound = t.getUpperBound();
308 break;
309 case DOWNWARDS:
310 bound = (t.getLowerBound() == null) ?
311 syms.botType :
312 t.getLowerBound();
313 break;
314 default:
315 Assert.error();
316 return null;
317 }
318 return bound.map(this, pkind);
319 } finally {
320 seen.remove(t);
321 }
322 } else {
323 //cycle
324 return pkind == ProjectionKind.UPWARDS ?
325 syms.objectType : syms.botType;
326 }
327 } else {
328 return t;
329 }
330 }
331
332 private Type mapTypeArgument(Type site, Type declaredBound, Type t, ProjectionKind pkind) {
333 return t.containsAny(vars) ?
334 t.map(new TypeArgumentProjection(site, declaredBound), pkind) :
335 t;
336 }
337
338 class TypeArgumentProjection extends TypeMapping<ProjectionKind> {
339
340 Type site;
341 Type declaredBound;
342
343 TypeArgumentProjection(Type site, Type declaredBound) {
344 this.site = site;
345 this.declaredBound = declaredBound;
346 }
347
348 @Override
349 public Type visitType(Type t, ProjectionKind pkind) {
350 //type argument is some type containing restricted vars
351 if (pkind == ProjectionKind.DOWNWARDS) {
352 //not defined
353 return syms.botType;
354 }
355 Type upper = t.map(TypeProjection.this, ProjectionKind.UPWARDS);
356 Type lower = t.map(TypeProjection.this, ProjectionKind.DOWNWARDS);
357 List<Type> formals = site.tsym.type.getTypeArguments();
358 BoundKind bk;
359 Type bound;
360 if (!isSameType(upper, syms.objectType) &&
361 (declaredBound.containsAny(formals) ||
362 !isSubtype(declaredBound, upper))) {
363 bound = upper;
364 bk = EXTENDS;
365 } else if (!lower.hasTag(BOT)) {
366 bound = lower;
367 bk = SUPER;
368 } else {
369 bound = syms.objectType;
370 bk = UNBOUND;
371 }
372 return makeWildcard(bound, bk);
373 }
374
375 @Override
376 public Type visitWildcardType(WildcardType wt, ProjectionKind pkind) {
377 //type argument is some wildcard whose bound contains restricted vars
378 Type bound = syms.botType;
379 BoundKind bk = wt.kind;
380 switch (wt.kind) {
381 case EXTENDS:
382 bound = wt.type.map(TypeProjection.this, pkind);
383 if (bound.hasTag(BOT)) {
384 return syms.botType;
385 }
386 break;
387 case SUPER:
388 bound = wt.type.map(TypeProjection.this, pkind.complement());
389 if (bound.hasTag(BOT)) {
390 bound = syms.objectType;
391 bk = UNBOUND;
392 }
393 break;
394 }
395 return makeWildcard(bound, bk);
396 }
397
398 private Type makeWildcard(Type bound, BoundKind bk) {
399 return new WildcardType(bound, bk, syms.boundClass) {
400 @Override
401 protected boolean needsStripping() {
402 return true;
403 }
404 };
405 }
406 }
407 }
408
409 /**
410 * Computes an upward projection of given type, and vars. See {@link TypeProjection}.
411 *
412 * @param t the type to be projected
413 * @param vars the set of type variables to be mapped
414 * @return the type obtained as result of the projection
415 */
416 public Type upward(Type t, List<Type> vars) {
417 return t.map(new TypeProjection(vars), ProjectionKind.UPWARDS);
418 }
419
420 /**
421 * Computes the set of captured variables mentioned in a given type. See {@link CaptureScanner}.
422 * This routine is typically used to computed the input set of variables to be used during
423 * an upwards projection (see {@link Types#upward(Type, List)}).
424 *
425 * @param t the type where occurrences of captured variables have to be found
426 * @return the set of captured variables found in t
427 */
428 public List<Type> captures(Type t) {
429 CaptureScanner cs = new CaptureScanner();
430 Set<Type> captures = new HashSet<>();
431 cs.visit(t, captures);
432 return List.from(captures);
433 }
434
435 /**
436 * This visitor scans a type recursively looking for occurrences of captured type variables.
437 */
438 class CaptureScanner extends SimpleVisitor<Void, Set<Type>> {
439
440 @Override
441 public Void visitType(Type t, Set<Type> types) {
442 return null;
443 }
444
445 @Override
446 public Void visitClassType(ClassType t, Set<Type> seen) {
447 if (t.isCompound()) {
448 directSupertypes(t).forEach(s -> visit(s, seen));
449 } else {
450 t.allparams().forEach(ta -> visit(ta, seen));
451 }
452 return null;
453 }
454
455 @Override
456 public Void visitArrayType(ArrayType t, Set<Type> seen) {
457 return visit(t.elemtype, seen);
458 }
459
460 @Override
461 public Void visitWildcardType(WildcardType t, Set<Type> seen) {
462 visit(t.type, seen);
463 return null;
464 }
465
466 @Override
467 public Void visitTypeVar(TypeVar t, Set<Type> seen) {
468 if ((t.tsym.flags() & Flags.SYNTHETIC) != 0 && seen.add(t)) {
469 visit(t.getUpperBound(), seen);
470 }
471 return null;
472 }
473
474 @Override
475 public Void visitCapturedType(CapturedType t, Set<Type> seen) {
476 if (seen.add(t)) {
477 visit(t.getUpperBound(), seen);
478 visit(t.getLowerBound(), seen);
479 }
480 return null;
481 }
482 }
483
484 // </editor-fold>
485
486 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
487 /**
488 * Checks that all the arguments to a class are unbounded
489 * wildcards or something else that doesn't make any restrictions
490 * on the arguments. If a class isUnbounded, a raw super- or
491 * subclass can be cast to it without a warning.
492 * @param t a type
493 * @return true iff the given type is unbounded or raw
494 */
495 public boolean isUnbounded(Type t) {
496 return isUnbounded.visit(t);
497 }
498 // where
499 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
500
501 public Boolean visitType(Type t, Void ignored) {
502 return true;
503 }
504
505 @Override
506 public Boolean visitClassType(ClassType t, Void ignored) {
507 List<Type> parms = t.tsym.type.allparams();
508 List<Type> args = t.allparams();
509 while (parms.nonEmpty()) {
510 WildcardType unb = new WildcardType(syms.objectType,
511 BoundKind.UNBOUND,
512 syms.boundClass,
513 (TypeVar)parms.head);
514 if (!containsType(args.head, unb))
515 return false;
516 parms = parms.tail;
517 args = args.tail;
518 }
519 return true;
520 }
521 };
522 // </editor-fold>
523
524 // <editor-fold defaultstate="collapsed" desc="asSub">
525 /**
526 * Return the least specific subtype of t that starts with symbol
527 * sym. If none exists, return null. The least specific subtype
528 * is determined as follows:
529 *
530 * <p>If there is exactly one parameterized instance of sym that is a
531 * subtype of t, that parameterized instance is returned.<br>
532 * Otherwise, if the plain type or raw type `sym' is a subtype of
533 * type t, the type `sym' itself is returned. Otherwise, null is
534 * returned.
535 */
536 public Type asSub(Type t, Symbol sym) {
537 return asSub.visit(t, sym);
538 }
539 // where
540 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
541
542 public Type visitType(Type t, Symbol sym) {
543 return null;
544 }
545
546 @Override
547 public Type visitClassType(ClassType t, Symbol sym) {
548 if (t.tsym == sym)
549 return t;
550 Type base = asSuper(sym.type, t.tsym);
551 if (base == null)
552 return null;
553 ListBuffer<Type> from = new ListBuffer<>();
554 ListBuffer<Type> to = new ListBuffer<>();
555 try {
556 adapt(base, t, from, to);
557 } catch (AdaptFailure ex) {
558 return null;
559 }
560 Type res = subst(sym.type, from.toList(), to.toList());
561 if (!isSubtype(res, t))
562 return null;
563 ListBuffer<Type> openVars = new ListBuffer<>();
564 for (List<Type> l = sym.type.allparams();
565 l.nonEmpty(); l = l.tail)
566 if (res.contains(l.head) && !t.contains(l.head))
567 openVars.append(l.head);
568 if (openVars.nonEmpty()) {
569 if (t.isRaw()) {
570 // The subtype of a raw type is raw
571 res = erasure(res);
572 } else {
573 // Unbound type arguments default to ?
574 List<Type> opens = openVars.toList();
575 ListBuffer<Type> qs = new ListBuffer<>();
576 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
577 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND,
578 syms.boundClass, (TypeVar) iter.head));
579 }
580 res = subst(res, opens, qs.toList());
581 }
582 }
583 return res;
584 }
585
586 @Override
587 public Type visitErrorType(ErrorType t, Symbol sym) {
588 return t;
589 }
590 };
591 // </editor-fold>
592
593 // <editor-fold defaultstate="collapsed" desc="isConvertible">
594 /**
595 * Is t a subtype of or convertible via boxing/unboxing
596 * conversion to s?
597 */
598 public boolean isConvertible(Type t, Type s, Warner warn) {
599 if (t.hasTag(ERROR)) {
600 return true;
601 }
602 boolean tPrimitive = t.isPrimitive();
603 boolean sPrimitive = s.isPrimitive();
604 if (tPrimitive == sPrimitive) {
605 return isSubtypeUnchecked(t, s, warn);
606 }
607 boolean tUndet = t.hasTag(UNDETVAR);
608 boolean sUndet = s.hasTag(UNDETVAR);
609
610 if (tUndet || sUndet) {
611 return tUndet ?
612 isSubtype(t, boxedTypeOrType(s)) :
613 isSubtype(boxedTypeOrType(t), s);
614 }
615
616 return tPrimitive
617 ? isSubtype(boxedClass(t).type, s)
618 : isSubtype(unboxedType(t), s);
619 }
620
621 /**
622 * Is t a subtype of or convertible via boxing/unboxing
623 * conversions to s?
624 */
625 public boolean isConvertible(Type t, Type s) {
626 return isConvertible(t, s, noWarnings);
627 }
628 // </editor-fold>
629
630 // <editor-fold defaultstate="collapsed" desc="findSam">
631
632 /**
633 * Exception used to report a function descriptor lookup failure. The exception
634 * wraps a diagnostic that can be used to generate more details error
635 * messages.
636 */
637 public static class FunctionDescriptorLookupError extends RuntimeException {
638 private static final long serialVersionUID = 0;
639
640 transient JCDiagnostic diagnostic;
641
642 FunctionDescriptorLookupError() {
643 this.diagnostic = null;
644 }
645
646 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
647 this.diagnostic = diag;
648 return this;
649 }
650
651 public JCDiagnostic getDiagnostic() {
652 return diagnostic;
653 }
654
655 @Override
656 public Throwable fillInStackTrace() {
657 // This is an internal exception; the stack trace is irrelevant.
658 return this;
659 }
660 }
661
662 /**
663 * A cache that keeps track of function descriptors associated with given
664 * functional interfaces.
665 */
666 class DescriptorCache {
667
668 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<>();
669
670 class FunctionDescriptor {
671 Symbol descSym;
672
673 FunctionDescriptor(Symbol descSym) {
674 this.descSym = descSym;
675 }
676
677 public Symbol getSymbol() {
678 return descSym;
679 }
680
681 public Type getType(Type site) {
682 site = removeWildcards(site);
683 if (site.isIntersection()) {
684 IntersectionClassType ict = (IntersectionClassType)site;
685 for (Type component : ict.getExplicitComponents()) {
686 if (!chk.checkValidGenericType(component)) {
687 //if the inferred functional interface type is not well-formed,
688 //or if it's not a subtype of the original target, issue an error
689 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
690 }
691 }
692 } else {
693 if (!chk.checkValidGenericType(site)) {
694 //if the inferred functional interface type is not well-formed,
695 //or if it's not a subtype of the original target, issue an error
696 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
697 }
698 }
699 return memberType(site, descSym);
700 }
701 }
702
703 class Entry {
704 final FunctionDescriptor cachedDescRes;
705 final int prevMark;
706
707 public Entry(FunctionDescriptor cachedDescRes,
708 int prevMark) {
709 this.cachedDescRes = cachedDescRes;
710 this.prevMark = prevMark;
711 }
712
713 boolean matches(int mark) {
714 return this.prevMark == mark;
715 }
716 }
717
718 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
719 Entry e = _map.get(origin);
720 CompoundScope members = membersClosure(origin.type, false);
721 if (e == null ||
722 !e.matches(members.getMark())) {
723 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
724 _map.put(origin, new Entry(descRes, members.getMark()));
725 return descRes;
726 }
727 else {
728 return e.cachedDescRes;
729 }
730 }
731
732 /**
733 * Compute the function descriptor associated with a given functional interface
734 */
735 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin,
736 CompoundScope membersCache) throws FunctionDescriptorLookupError {
737 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0 || origin.isSealed()) {
738 //t must be an interface
739 throw failure("not.a.functional.intf", origin);
740 }
741
742 final ListBuffer<Symbol> abstracts = new ListBuffer<>();
743 for (Symbol sym : membersCache.getSymbols(new DescriptorFilter(origin))) {
744 Type mtype = memberType(origin.type, sym);
745 if (abstracts.isEmpty()) {
746 abstracts.append(sym);
747 } else if ((sym.name == abstracts.first().name &&
748 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
749 if (!abstracts.stream().filter(msym -> msym.owner.isSubClass(sym.enclClass(), Types.this))
750 .map(msym -> memberType(origin.type, msym))
751 .anyMatch(abstractMType -> isSubSignature(abstractMType, mtype))) {
752 abstracts.append(sym);
753 }
754 } else {
755 //the target method(s) should be the only abstract members of t
756 throw failure("not.a.functional.intf.1", origin,
757 diags.fragment(Fragments.IncompatibleAbstracts(Kinds.kindName(origin), origin)));
758 }
759 }
760 if (abstracts.isEmpty()) {
761 //t must define a suitable non-generic method
762 throw failure("not.a.functional.intf.1", origin,
763 diags.fragment(Fragments.NoAbstracts(Kinds.kindName(origin), origin)));
764 } else if (abstracts.size() == 1) {
765 return new FunctionDescriptor(abstracts.first());
766 } else { // size > 1
767 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
768 if (descRes == null) {
769 //we can get here if the functional interface is ill-formed
770 ListBuffer<JCDiagnostic> descriptors = new ListBuffer<>();
771 for (Symbol desc : abstracts) {
772 String key = desc.type.getThrownTypes().nonEmpty() ?
773 "descriptor.throws" : "descriptor";
774 descriptors.append(diags.fragment(key, desc.name,
775 desc.type.getParameterTypes(),
776 desc.type.getReturnType(),
777 desc.type.getThrownTypes()));
778 }
779 JCDiagnostic msg =
780 diags.fragment(Fragments.IncompatibleDescsInFunctionalIntf(Kinds.kindName(origin),
781 origin));
782 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
783 new JCDiagnostic.MultilineDiagnostic(msg, descriptors.toList());
784 throw failure(incompatibleDescriptors);
785 }
786 return descRes;
787 }
788 }
789
790 /**
791 * Compute a synthetic type for the target descriptor given a list
792 * of override-equivalent methods in the functional interface type.
793 * The resulting method type is a method type that is override-equivalent
794 * and return-type substitutable with each method in the original list.
795 */
796 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
797 return mergeAbstracts(methodSyms, origin.type, false)
798 .map(bestSoFar -> new FunctionDescriptor(bestSoFar.baseSymbol()) {
799 @Override
800 public Type getType(Type origin) {
801 Type mt = memberType(origin, getSymbol());
802 return createMethodTypeWithThrown(mt, bestSoFar.type.getThrownTypes());
803 }
804 }).orElse(null);
805 }
806
807 FunctionDescriptorLookupError failure(String msg, Object... args) {
808 return failure(diags.fragment(msg, args));
809 }
810
811 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
812 return new FunctionDescriptorLookupError().setMessage(diag);
813 }
814 }
815
816 private DescriptorCache descCache = new DescriptorCache();
817
818 /**
819 * Find the method descriptor associated to this class symbol - if the
820 * symbol 'origin' is not a functional interface, an exception is thrown.
821 */
822 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
823 return descCache.get(origin).getSymbol();
824 }
825
826 /**
827 * Find the type of the method descriptor associated to this class symbol -
828 * if the symbol 'origin' is not a functional interface, an exception is thrown.
829 */
830 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
831 return descCache.get(origin.tsym).getType(origin);
832 }
833
834 /**
835 * Is given type a functional interface?
836 */
837 public boolean isFunctionalInterface(TypeSymbol tsym) {
838 try {
839 findDescriptorSymbol(tsym);
840 return true;
841 } catch (FunctionDescriptorLookupError ex) {
842 return false;
843 }
844 }
845
846 public boolean isFunctionalInterface(Type site) {
847 try {
848 findDescriptorType(site);
849 return true;
850 } catch (FunctionDescriptorLookupError ex) {
851 return false;
852 }
853 }
854
855 public Type removeWildcards(Type site) {
856 if (site.getTypeArguments().stream().anyMatch(t -> t.hasTag(WILDCARD))) {
857 //compute non-wildcard parameterization - JLS 9.9
858 List<Type> actuals = site.getTypeArguments();
859 List<Type> formals = site.tsym.type.getTypeArguments();
860 ListBuffer<Type> targs = new ListBuffer<>();
861 for (Type formal : formals) {
862 Type actual = actuals.head;
863 Type bound = formal.getUpperBound();
864 if (actuals.head.hasTag(WILDCARD)) {
865 WildcardType wt = (WildcardType)actual;
866 //check that bound does not contain other formals
867 if (bound.containsAny(formals)) {
868 targs.add(wt.type);
869 } else {
870 //compute new type-argument based on declared bound and wildcard bound
871 switch (wt.kind) {
872 case UNBOUND:
873 targs.add(bound);
874 break;
875 case EXTENDS:
876 targs.add(glb(bound, wt.type));
877 break;
878 case SUPER:
879 targs.add(wt.type);
880 break;
881 default:
882 Assert.error("Cannot get here!");
883 }
884 }
885 } else {
886 //not a wildcard - the new type argument remains unchanged
887 targs.add(actual);
888 }
889 actuals = actuals.tail;
890 }
891 return subst(site.tsym.type, formals, targs.toList());
892 } else {
893 return site;
894 }
895 }
896
897 /**
898 * Create a symbol for a class that implements a given functional interface
899 * and overrides its functional descriptor. This routine is used for two
900 * main purposes: (i) checking well-formedness of a functional interface;
901 * (ii) perform functional interface bridge calculation.
902 */
903 public ClassSymbol makeFunctionalInterfaceClass(Env<AttrContext> env, Name name, Type target, long cflags) {
904 if (target == null || target == syms.unknownType) {
905 return null;
906 }
907 Symbol descSym = findDescriptorSymbol(target.tsym);
908 Type descType = findDescriptorType(target);
909 ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass());
910 csym.completer = Completer.NULL_COMPLETER;
911 csym.members_field = WriteableScope.create(csym);
912 MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym);
913 csym.members_field.enter(instDescSym);
914 Type.ClassType ctype = new Type.ClassType(Type.noType, List.nil(), csym);
915 ctype.supertype_field = syms.objectType;
916 ctype.interfaces_field = target.isIntersection() ?
917 directSupertypes(target) :
918 List.of(target);
919 csym.type = ctype;
920 csym.sourcefile = ((ClassSymbol)csym.owner).sourcefile;
921 return csym;
922 }
923
924 /**
925 * Find the minimal set of methods that are overridden by the functional
926 * descriptor in 'origin'. All returned methods are assumed to have different
927 * erased signatures.
928 */
929 public List<Symbol> functionalInterfaceBridges(TypeSymbol origin) {
930 Assert.check(isFunctionalInterface(origin));
931 Symbol descSym = findDescriptorSymbol(origin);
932 CompoundScope members = membersClosure(origin.type, false);
933 ListBuffer<Symbol> overridden = new ListBuffer<>();
934 outer: for (Symbol m2 : members.getSymbolsByName(descSym.name, bridgeFilter)) {
935 if (m2 == descSym) continue;
936 else if (descSym.overrides(m2, origin, Types.this, false)) {
937 for (Symbol m3 : overridden) {
938 if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) ||
939 (m3.overrides(m2, origin, Types.this, false) &&
940 (pendingBridges((ClassSymbol)origin, m3.enclClass()) ||
941 (((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) {
942 continue outer;
943 }
944 }
945 overridden.add(m2);
946 }
947 }
948 return overridden.toList();
949 }
950 //where
951 // Use anonymous class instead of lambda expression intentionally,
952 // because the variable `names` has modifier: final.
953 private Predicate<Symbol> bridgeFilter = new Predicate<Symbol>() {
954 public boolean test(Symbol t) {
955 return t.kind == MTH &&
956 t.name != names.init &&
957 t.name != names.clinit &&
958 (t.flags() & SYNTHETIC) == 0;
959 }
960 };
961
962 private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) {
963 //a symbol will be completed from a classfile if (a) symbol has
964 //an associated file object with CLASS kind and (b) the symbol has
965 //not been entered
966 if (origin.classfile != null &&
967 origin.classfile.getKind() == JavaFileObject.Kind.CLASS &&
968 enter.getEnv(origin) == null) {
969 return false;
970 }
971 if (origin == s) {
972 return true;
973 }
974 for (Type t : interfaces(origin.type)) {
975 if (pendingBridges((ClassSymbol)t.tsym, s)) {
976 return true;
977 }
978 }
979 return false;
980 }
981 // </editor-fold>
982
983 /**
984 * Scope filter used to skip methods that should be ignored (such as methods
985 * overridden by j.l.Object) during function interface conversion interface check
986 */
987 class DescriptorFilter implements Predicate<Symbol> {
988
989 TypeSymbol origin;
990
991 DescriptorFilter(TypeSymbol origin) {
992 this.origin = origin;
993 }
994
995 @Override
996 public boolean test(Symbol sym) {
997 return sym.kind == MTH &&
998 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
999 !overridesObjectMethod(origin, sym) &&
1000 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
1001 }
1002 }
1003
1004 // <editor-fold defaultstate="collapsed" desc="isSubtype">
1005 /**
1006 * Is t an unchecked subtype of s?
1007 */
1008 public boolean isSubtypeUnchecked(Type t, Type s) {
1009 return isSubtypeUnchecked(t, s, noWarnings);
1010 }
1011 /**
1012 * Is t an unchecked subtype of s?
1013 */
1014 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
1015 boolean result = isSubtypeUncheckedInternal(t, s, true, warn);
1016 if (result) {
1017 checkUnsafeVarargsConversion(t, s, warn);
1018 }
1019 return result;
1020 }
1021 //where
1022 private boolean isSubtypeUncheckedInternal(Type t, Type s, boolean capture, Warner warn) {
1023 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
1024 if (((ArrayType)t).elemtype.isPrimitive()) {
1025 return isSameType(elemtype(t), elemtype(s));
1026 } else {
1027 return isSubtypeUncheckedInternal(elemtype(t), elemtype(s), false, warn);
1028 }
1029 } else if (isSubtype(t, s, capture)) {
1030 return true;
1031 } else if (t.hasTag(TYPEVAR)) {
1032 return isSubtypeUncheckedInternal(t.getUpperBound(), s, false, warn);
1033 } else if (!s.isRaw()) {
1034 Type t2 = asSuper(t, s.tsym);
1035 if (t2 != null && t2.isRaw()) {
1036 if (isReifiable(s)) {
1037 warn.silentWarn(LintCategory.UNCHECKED);
1038 } else {
1039 warn.warn(LintCategory.UNCHECKED);
1040 }
1041 return true;
1042 }
1043 }
1044 return false;
1045 }
1046
1047 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
1048 if (!t.hasTag(ARRAY) || isReifiable(t)) {
1049 return;
1050 }
1051 ArrayType from = (ArrayType)t;
1052 boolean shouldWarn = false;
1053 switch (s.getTag()) {
1054 case ARRAY:
1055 ArrayType to = (ArrayType)s;
1056 shouldWarn = from.isVarargs() &&
1057 !to.isVarargs() &&
1058 !isReifiable(from);
1059 break;
1060 case CLASS:
1061 shouldWarn = from.isVarargs();
1062 break;
1063 }
1064 if (shouldWarn) {
1065 warn.warn(LintCategory.VARARGS);
1066 }
1067 }
1068
1069 /**
1070 * Is t a subtype of s?<br>
1071 * (not defined for Method and ForAll types)
1072 */
1073 public final boolean isSubtype(Type t, Type s) {
1074 return isSubtype(t, s, true);
1075 }
1076 public final boolean isSubtypeNoCapture(Type t, Type s) {
1077 return isSubtype(t, s, false);
1078 }
1079 public boolean isSubtype(Type t, Type s, boolean capture) {
1080 if (t.equalsIgnoreMetadata(s))
1081 return true;
1082 if (s.isPartial())
1083 return isSuperType(s, t);
1084
1085 if (s.isCompound()) {
1086 for (Type s2 : interfaces(s).prepend(supertype(s))) {
1087 if (!isSubtype(t, s2, capture))
1088 return false;
1089 }
1090 return true;
1091 }
1092
1093 // Generally, if 's' is a lower-bounded type variable, recur on lower bound; but
1094 // for inference variables and intersections, we need to keep 's'
1095 // (see JLS 4.10.2 for intersections and 18.2.3 for inference vars)
1096 if (!t.hasTag(UNDETVAR) && !t.isCompound()) {
1097 // TODO: JDK-8039198, bounds checking sometimes passes in a wildcard as s
1098 Type lower = cvarLowerBound(wildLowerBound(s));
1099 if (s != lower && !lower.hasTag(BOT))
1100 return isSubtype(capture ? capture(t) : t, lower, false);
1101 }
1102
1103 return isSubtype.visit(capture ? capture(t) : t, s);
1104 }
1105 // where
1106 private TypeRelation isSubtype = new TypeRelation()
1107 {
1108 @Override
1109 public Boolean visitType(Type t, Type s) {
1110 switch (t.getTag()) {
1111 case BYTE:
1112 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
1113 case CHAR:
1114 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
1115 case SHORT: case INT: case LONG:
1116 case FLOAT: case DOUBLE:
1117 return t.getTag().isSubRangeOf(s.getTag());
1118 case BOOLEAN: case VOID:
1119 return t.hasTag(s.getTag());
1120 case TYPEVAR:
1121 return isSubtypeNoCapture(t.getUpperBound(), s);
1122 case BOT:
1123 return
1124 s.hasTag(BOT) || s.hasTag(CLASS) ||
1125 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
1126 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
1127 case NONE:
1128 return false;
1129 default:
1130 throw new AssertionError("isSubtype " + t.getTag());
1131 }
1132 }
1133
1134 private Set<TypePair> cache = new HashSet<>();
1135
1136 private boolean containsTypeRecursive(Type t, Type s) {
1137 TypePair pair = new TypePair(t, s);
1138 if (cache.add(pair)) {
1139 try {
1140 return containsType(t.getTypeArguments(),
1141 s.getTypeArguments());
1142 } finally {
1143 cache.remove(pair);
1144 }
1145 } else {
1146 return containsType(t.getTypeArguments(),
1147 rewriteSupers(s).getTypeArguments());
1148 }
1149 }
1150
1151 private Type rewriteSupers(Type t) {
1152 if (!t.isParameterized())
1153 return t;
1154 ListBuffer<Type> from = new ListBuffer<>();
1155 ListBuffer<Type> to = new ListBuffer<>();
1156 adaptSelf(t, from, to);
1157 if (from.isEmpty())
1158 return t;
1159 ListBuffer<Type> rewrite = new ListBuffer<>();
1160 boolean changed = false;
1161 for (Type orig : to.toList()) {
1162 Type s = rewriteSupers(orig);
1163 if (s.isSuperBound() && !s.isExtendsBound()) {
1164 s = new WildcardType(syms.objectType,
1165 BoundKind.UNBOUND,
1166 syms.boundClass,
1167 s.getMetadata());
1168 changed = true;
1169 } else if (s != orig) {
1170 s = new WildcardType(wildUpperBound(s),
1171 BoundKind.EXTENDS,
1172 syms.boundClass,
1173 s.getMetadata());
1174 changed = true;
1175 }
1176 rewrite.append(s);
1177 }
1178 if (changed)
1179 return subst(t.tsym.type, from.toList(), rewrite.toList());
1180 else
1181 return t;
1182 }
1183
1184 @Override
1185 public Boolean visitClassType(ClassType t, Type s) {
1186 Type sup = asSuper(t, s.tsym);
1187 if (sup == null) return false;
1188 // If t is an intersection, sup might not be a class type
1189 if (!sup.hasTag(CLASS)) return isSubtypeNoCapture(sup, s);
1190 return sup.tsym == s.tsym
1191 // Check type variable containment
1192 && (!s.isParameterized() || containsTypeRecursive(s, sup))
1193 && isSubtypeNoCapture(sup.getEnclosingType(),
1194 s.getEnclosingType());
1195 }
1196
1197 @Override
1198 public Boolean visitArrayType(ArrayType t, Type s) {
1199 if (s.hasTag(ARRAY)) {
1200 if (t.elemtype.isPrimitive())
1201 return isSameType(t.elemtype, elemtype(s));
1202 else
1203 return isSubtypeNoCapture(t.elemtype, elemtype(s));
1204 }
1205
1206 if (s.hasTag(CLASS)) {
1207 Name sname = s.tsym.getQualifiedName();
1208 return sname == names.java_lang_Object
1209 || sname == names.java_lang_Cloneable
1210 || sname == names.java_io_Serializable;
1211 }
1212
1213 return false;
1214 }
1215
1216 @Override
1217 public Boolean visitUndetVar(UndetVar t, Type s) {
1218 //todo: test against origin needed? or replace with substitution?
1219 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
1220 return true;
1221 } else if (s.hasTag(BOT)) {
1222 //if 's' is 'null' there's no instantiated type U for which
1223 //U <: s (but 'null' itself, which is not a valid type)
1224 return false;
1225 }
1226
1227 t.addBound(InferenceBound.UPPER, s, Types.this);
1228 return true;
1229 }
1230
1231 @Override
1232 public Boolean visitErrorType(ErrorType t, Type s) {
1233 return true;
1234 }
1235 };
1236
1237 /**
1238 * Is t a subtype of every type in given list `ts'?<br>
1239 * (not defined for Method and ForAll types)<br>
1240 * Allows unchecked conversions.
1241 */
1242 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
1243 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
1244 if (!isSubtypeUnchecked(t, l.head, warn))
1245 return false;
1246 return true;
1247 }
1248
1249 /**
1250 * Are corresponding elements of ts subtypes of ss? If lists are
1251 * of different length, return false.
1252 */
1253 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
1254 while (ts.tail != null && ss.tail != null
1255 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1256 isSubtype(ts.head, ss.head)) {
1257 ts = ts.tail;
1258 ss = ss.tail;
1259 }
1260 return ts.tail == null && ss.tail == null;
1261 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1262 }
1263
1264 /**
1265 * Are corresponding elements of ts subtypes of ss, allowing
1266 * unchecked conversions? If lists are of different length,
1267 * return false.
1268 **/
1269 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
1270 while (ts.tail != null && ss.tail != null
1271 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1272 isSubtypeUnchecked(ts.head, ss.head, warn)) {
1273 ts = ts.tail;
1274 ss = ss.tail;
1275 }
1276 return ts.tail == null && ss.tail == null;
1277 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1278 }
1279 // </editor-fold>
1280
1281 // <editor-fold defaultstate="collapsed" desc="isSuperType">
1282 /**
1283 * Is t a supertype of s?
1284 */
1285 public boolean isSuperType(Type t, Type s) {
1286 switch (t.getTag()) {
1287 case ERROR:
1288 return true;
1289 case UNDETVAR: {
1290 UndetVar undet = (UndetVar)t;
1291 if (t == s ||
1292 undet.qtype == s ||
1293 s.hasTag(ERROR) ||
1294 s.hasTag(BOT)) {
1295 return true;
1296 }
1297 undet.addBound(InferenceBound.LOWER, s, this);
1298 return true;
1299 }
1300 default:
1301 return isSubtype(s, t);
1302 }
1303 }
1304 // </editor-fold>
1305
1306 // <editor-fold defaultstate="collapsed" desc="isSameType">
1307 /**
1308 * Are corresponding elements of the lists the same type? If
1309 * lists are of different length, return false.
1310 */
1311 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
1312 while (ts.tail != null && ss.tail != null
1313 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1314 isSameType(ts.head, ss.head)) {
1315 ts = ts.tail;
1316 ss = ss.tail;
1317 }
1318 return ts.tail == null && ss.tail == null;
1319 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1320 }
1321
1322 /**
1323 * A polymorphic signature method (JLS 15.12.3) is a method that
1324 * (i) is declared in the java.lang.invoke.MethodHandle/VarHandle classes;
1325 * (ii) takes a single variable arity parameter;
1326 * (iii) whose declared type is Object[];
1327 * (iv) has any return type, Object signifying a polymorphic return type; and
1328 * (v) is native.
1329 */
1330 public boolean isSignaturePolymorphic(MethodSymbol msym) {
1331 List<Type> argtypes = msym.type.getParameterTypes();
1332 return (msym.flags_field & NATIVE) != 0 &&
1333 (msym.owner == syms.methodHandleType.tsym || msym.owner == syms.varHandleType.tsym) &&
1334 argtypes.length() == 1 &&
1335 argtypes.head.hasTag(TypeTag.ARRAY) &&
1336 ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym;
1337 }
1338
1339 /**
1340 * Is t the same type as s?
1341 */
1342 public boolean isSameType(Type t, Type s) {
1343 return isSameTypeVisitor.visit(t, s);
1344 }
1345 // where
1346
1347 /**
1348 * Type-equality relation - type variables are considered
1349 * equals if they share the same object identity.
1350 */
1351 TypeRelation isSameTypeVisitor = new TypeRelation() {
1352
1353 public Boolean visitType(Type t, Type s) {
1354 if (t.equalsIgnoreMetadata(s))
1355 return true;
1356
1357 if (s.isPartial())
1358 return visit(s, t);
1359
1360 switch (t.getTag()) {
1361 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1362 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
1363 return t.hasTag(s.getTag());
1364 case TYPEVAR: {
1365 if (s.hasTag(TYPEVAR)) {
1366 //type-substitution does not preserve type-var types
1367 //check that type var symbols and bounds are indeed the same
1368 return t == s;
1369 }
1370 else {
1371 //special case for s == ? super X, where upper(s) = u
1372 //check that u == t, where u has been set by Type.withTypeVar
1373 return s.isSuperBound() &&
1374 !s.isExtendsBound() &&
1375 visit(t, wildUpperBound(s));
1376 }
1377 }
1378 default:
1379 throw new AssertionError("isSameType " + t.getTag());
1380 }
1381 }
1382
1383 @Override
1384 public Boolean visitWildcardType(WildcardType t, Type s) {
1385 if (!s.hasTag(WILDCARD)) {
1386 return false;
1387 } else {
1388 WildcardType t2 = (WildcardType)s;
1389 return (t.kind == t2.kind || (t.isExtendsBound() && s.isExtendsBound())) &&
1390 isSameType(t.type, t2.type);
1391 }
1392 }
1393
1394 @Override
1395 public Boolean visitClassType(ClassType t, Type s) {
1396 if (t == s)
1397 return true;
1398
1399 if (s.isPartial())
1400 return visit(s, t);
1401
1402 if (s.isSuperBound() && !s.isExtendsBound())
1403 return visit(t, wildUpperBound(s)) && visit(t, wildLowerBound(s));
1404
1405 if (t.isCompound() && s.isCompound()) {
1406 if (!visit(supertype(t), supertype(s)))
1407 return false;
1408
1409 Map<Symbol,Type> tMap = new HashMap<>();
1410 for (Type ti : interfaces(t)) {
1411 tMap.put(ti.tsym, ti);
1412 }
1413 for (Type si : interfaces(s)) {
1414 if (!tMap.containsKey(si.tsym))
1415 return false;
1416 Type ti = tMap.remove(si.tsym);
1417 if (!visit(ti, si))
1418 return false;
1419 }
1420 return tMap.isEmpty();
1421 }
1422 return t.tsym == s.tsym
1423 && visit(t.getEnclosingType(), s.getEnclosingType())
1424 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
1425 }
1426
1427 @Override
1428 public Boolean visitArrayType(ArrayType t, Type s) {
1429 if (t == s)
1430 return true;
1431
1432 if (s.isPartial())
1433 return visit(s, t);
1434
1435 return s.hasTag(ARRAY)
1436 && containsTypeEquivalent(t.elemtype, elemtype(s));
1437 }
1438
1439 @Override
1440 public Boolean visitMethodType(MethodType t, Type s) {
1441 // isSameType for methods does not take thrown
1442 // exceptions into account!
1443 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
1444 }
1445
1446 @Override
1447 public Boolean visitPackageType(PackageType t, Type s) {
1448 return t == s;
1449 }
1450
1451 @Override
1452 public Boolean visitForAll(ForAll t, Type s) {
1453 if (!s.hasTag(FORALL)) {
1454 return false;
1455 }
1456
1457 ForAll forAll = (ForAll)s;
1458 return hasSameBounds(t, forAll)
1459 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1460 }
1461
1462 @Override
1463 public Boolean visitUndetVar(UndetVar t, Type s) {
1464 if (s.hasTag(WILDCARD)) {
1465 // FIXME, this might be leftovers from before capture conversion
1466 return false;
1467 }
1468
1469 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
1470 return true;
1471 }
1472
1473 t.addBound(InferenceBound.EQ, s, Types.this);
1474
1475 return true;
1476 }
1477
1478 @Override
1479 public Boolean visitErrorType(ErrorType t, Type s) {
1480 return true;
1481 }
1482 };
1483
1484 // </editor-fold>
1485
1486 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1487 public boolean containedBy(Type t, Type s) {
1488 switch (t.getTag()) {
1489 case UNDETVAR:
1490 if (s.hasTag(WILDCARD)) {
1491 UndetVar undetvar = (UndetVar)t;
1492 WildcardType wt = (WildcardType)s;
1493 switch(wt.kind) {
1494 case UNBOUND:
1495 break;
1496 case EXTENDS: {
1497 Type bound = wildUpperBound(s);
1498 undetvar.addBound(InferenceBound.UPPER, bound, this);
1499 break;
1500 }
1501 case SUPER: {
1502 Type bound = wildLowerBound(s);
1503 undetvar.addBound(InferenceBound.LOWER, bound, this);
1504 break;
1505 }
1506 }
1507 return true;
1508 } else {
1509 return isSameType(t, s);
1510 }
1511 case ERROR:
1512 return true;
1513 default:
1514 return containsType(s, t);
1515 }
1516 }
1517
1518 boolean containsType(List<Type> ts, List<Type> ss) {
1519 while (ts.nonEmpty() && ss.nonEmpty()
1520 && containsType(ts.head, ss.head)) {
1521 ts = ts.tail;
1522 ss = ss.tail;
1523 }
1524 return ts.isEmpty() && ss.isEmpty();
1525 }
1526
1527 /**
1528 * Check if t contains s.
1529 *
1530 * <p>T contains S if:
1531 *
1532 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1533 *
1534 * <p>This relation is only used by ClassType.isSubtype(), that
1535 * is,
1536 *
1537 * <p>{@code C<S> <: C<T> if T contains S.}
1538 *
1539 * <p>Because of F-bounds, this relation can lead to infinite
1540 * recursion. Thus we must somehow break that recursion. Notice
1541 * that containsType() is only called from ClassType.isSubtype().
1542 * Since the arguments have already been checked against their
1543 * bounds, we know:
1544 *
1545 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1546 *
1547 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1548 *
1549 * @param t a type
1550 * @param s a type
1551 */
1552 public boolean containsType(Type t, Type s) {
1553 return containsType.visit(t, s);
1554 }
1555 // where
1556 private TypeRelation containsType = new TypeRelation() {
1557
1558 public Boolean visitType(Type t, Type s) {
1559 if (s.isPartial())
1560 return containedBy(s, t);
1561 else
1562 return isSameType(t, s);
1563 }
1564
1565 // void debugContainsType(WildcardType t, Type s) {
1566 // System.err.println();
1567 // System.err.format(" does %s contain %s?%n", t, s);
1568 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1569 // wildUpperBound(s), s, t, wildUpperBound(t),
1570 // t.isSuperBound()
1571 // || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t)));
1572 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1573 // wildLowerBound(t), t, s, wildLowerBound(s),
1574 // t.isExtendsBound()
1575 // || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s)));
1576 // System.err.println();
1577 // }
1578
1579 @Override
1580 public Boolean visitWildcardType(WildcardType t, Type s) {
1581 if (s.isPartial())
1582 return containedBy(s, t);
1583 else {
1584 // debugContainsType(t, s);
1585 return isSameWildcard(t, s)
1586 || isCaptureOf(s, t)
1587 || ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))) &&
1588 (t.isSuperBound() || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t))));
1589 }
1590 }
1591
1592 @Override
1593 public Boolean visitUndetVar(UndetVar t, Type s) {
1594 if (!s.hasTag(WILDCARD)) {
1595 return isSameType(t, s);
1596 } else {
1597 return false;
1598 }
1599 }
1600
1601 @Override
1602 public Boolean visitErrorType(ErrorType t, Type s) {
1603 return true;
1604 }
1605 };
1606
1607 public boolean isCaptureOf(Type s, WildcardType t) {
1608 if (!s.hasTag(TYPEVAR) || !((TypeVar)s).isCaptured())
1609 return false;
1610 return isSameWildcard(t, ((CapturedType)s).wildcard);
1611 }
1612
1613 public boolean isSameWildcard(WildcardType t, Type s) {
1614 if (!s.hasTag(WILDCARD))
1615 return false;
1616 WildcardType w = (WildcardType)s;
1617 return w.kind == t.kind && w.type == t.type;
1618 }
1619
1620 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1621 while (ts.nonEmpty() && ss.nonEmpty()
1622 && containsTypeEquivalent(ts.head, ss.head)) {
1623 ts = ts.tail;
1624 ss = ss.tail;
1625 }
1626 return ts.isEmpty() && ss.isEmpty();
1627 }
1628 // </editor-fold>
1629
1630 // <editor-fold defaultstate="collapsed" desc="isCastable">
1631 public boolean isCastable(Type t, Type s) {
1632 return isCastable(t, s, noWarnings);
1633 }
1634
1635 /**
1636 * Is t castable to s?<br>
1637 * s is assumed to be an erased type.<br>
1638 * (not defined for Method and ForAll types).
1639 */
1640 public boolean isCastable(Type t, Type s, Warner warn) {
1641 // if same type
1642 if (t == s)
1643 return true;
1644 // if one of the types is primitive
1645 if (t.isPrimitive() != s.isPrimitive()) {
1646 t = skipTypeVars(t, false);
1647 return (isConvertible(t, s, warn)
1648 || (s.isPrimitive() &&
1649 isSubtype(boxedClass(s).type, t)));
1650 }
1651 boolean result;
1652 if (warn != warnStack.head) {
1653 try {
1654 warnStack = warnStack.prepend(warn);
1655 checkUnsafeVarargsConversion(t, s, warn);
1656 result = isCastable.visit(t,s);
1657 } finally {
1658 warnStack = warnStack.tail;
1659 }
1660 } else {
1661 result = isCastable.visit(t,s);
1662 }
1663 if (result && t.hasTag(CLASS) && t.tsym.kind.matches(Kinds.KindSelector.TYP)
1664 && s.hasTag(CLASS) && s.tsym.kind.matches(Kinds.KindSelector.TYP)
1665 && (t.tsym.isSealed() || s.tsym.isSealed())) {
1666 return (t.isCompound() || s.isCompound()) ?
1667 true :
1668 !(new DisjointChecker().areDisjoint((ClassSymbol)t.tsym, (ClassSymbol)s.tsym));
1669 }
1670 return result;
1671 }
1672 // where
1673 class DisjointChecker {
1674 Set<Pair<ClassSymbol, ClassSymbol>> pairsSeen = new HashSet<>();
1675 private boolean areDisjoint(ClassSymbol ts, ClassSymbol ss) {
1676 Pair<ClassSymbol, ClassSymbol> newPair = new Pair<>(ts, ss);
1677 /* if we are seeing the same pair again then there is an issue with the sealed hierarchy
1678 * bail out, a detailed error will be reported downstream
1679 */
1680 if (!pairsSeen.add(newPair))
1681 return false;
1682 if (isSubtype(erasure(ts.type), erasure(ss.type))) {
1683 return false;
1684 }
1685 // if both are classes or both are interfaces, shortcut
1686 if (ts.isInterface() == ss.isInterface() && isSubtype(erasure(ss.type), erasure(ts.type))) {
1687 return false;
1688 }
1689 if (ts.isInterface() && !ss.isInterface()) {
1690 /* so ts is interface but ss is a class
1691 * an interface is disjoint from a class if the class is disjoint form the interface
1692 */
1693 return areDisjoint(ss, ts);
1694 }
1695 // a final class that is not subtype of ss is disjoint
1696 if (!ts.isInterface() && ts.isFinal()) {
1697 return true;
1698 }
1699 // if at least one is sealed
1700 if (ts.isSealed() || ss.isSealed()) {
1701 // permitted subtypes have to be disjoint with the other symbol
1702 ClassSymbol sealedOne = ts.isSealed() ? ts : ss;
1703 ClassSymbol other = sealedOne == ts ? ss : ts;
1704 return sealedOne.permitted.stream().allMatch(sym -> areDisjoint((ClassSymbol)sym, other));
1705 }
1706 return false;
1707 }
1708 }
1709
1710 private TypeRelation isCastable = new TypeRelation() {
1711
1712 public Boolean visitType(Type t, Type s) {
1713 if (s.hasTag(ERROR) || t.hasTag(NONE))
1714 return true;
1715
1716 switch (t.getTag()) {
1717 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1718 case DOUBLE:
1719 return s.isNumeric();
1720 case BOOLEAN:
1721 return s.hasTag(BOOLEAN);
1722 case VOID:
1723 return false;
1724 case BOT:
1725 return isSubtype(t, s);
1726 default:
1727 throw new AssertionError();
1728 }
1729 }
1730
1731 @Override
1732 public Boolean visitWildcardType(WildcardType t, Type s) {
1733 return isCastable(wildUpperBound(t), s, warnStack.head);
1734 }
1735
1736 @Override
1737 public Boolean visitClassType(ClassType t, Type s) {
1738 if (s.hasTag(ERROR) || s.hasTag(BOT))
1739 return true;
1740
1741 if (s.hasTag(TYPEVAR)) {
1742 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1743 warnStack.head.warn(LintCategory.UNCHECKED);
1744 return true;
1745 } else {
1746 return false;
1747 }
1748 }
1749
1750 if (t.isCompound() || s.isCompound()) {
1751 return !t.isCompound() ?
1752 visitCompoundType((ClassType)s, t, true) :
1753 visitCompoundType(t, s, false);
1754 }
1755
1756 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) {
1757 boolean upcast;
1758 if ((upcast = isSubtype(erasure(t), erasure(s)))
1759 || isSubtype(erasure(s), erasure(t))) {
1760 if (!upcast && s.hasTag(ARRAY)) {
1761 if (!isReifiable(s))
1762 warnStack.head.warn(LintCategory.UNCHECKED);
1763 return true;
1764 } else if (s.isRaw()) {
1765 return true;
1766 } else if (t.isRaw()) {
1767 if (!isUnbounded(s))
1768 warnStack.head.warn(LintCategory.UNCHECKED);
1769 return true;
1770 }
1771 // Assume |a| <: |b|
1772 final Type a = upcast ? t : s;
1773 final Type b = upcast ? s : t;
1774 final boolean HIGH = true;
1775 final boolean LOW = false;
1776 final boolean DONT_REWRITE_TYPEVARS = false;
1777 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1778 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1779 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1780 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1781 Type lowSub = asSub(bLow, aLow.tsym);
1782 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1783 if (highSub == null) {
1784 final boolean REWRITE_TYPEVARS = true;
1785 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1786 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1787 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1788 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1789 lowSub = asSub(bLow, aLow.tsym);
1790 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1791 }
1792 if (highSub != null) {
1793 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1794 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1795 }
1796 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1797 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1798 && !disjointTypes(aLow.allparams(), highSub.allparams())
1799 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1800 if (upcast ? giveWarning(a, b) :
1801 giveWarning(b, a))
1802 warnStack.head.warn(LintCategory.UNCHECKED);
1803 return true;
1804 }
1805 }
1806 if (isReifiable(s))
1807 return isSubtypeUnchecked(a, b);
1808 else
1809 return isSubtypeUnchecked(a, b, warnStack.head);
1810 }
1811
1812 // Sidecast
1813 if (s.hasTag(CLASS)) {
1814 if ((s.tsym.flags() & INTERFACE) != 0) {
1815 return ((t.tsym.flags() & FINAL) == 0)
1816 ? sideCast(t, s, warnStack.head)
1817 : sideCastFinal(t, s, warnStack.head);
1818 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1819 return ((s.tsym.flags() & FINAL) == 0)
1820 ? sideCast(t, s, warnStack.head)
1821 : sideCastFinal(t, s, warnStack.head);
1822 } else {
1823 // unrelated class types
1824 return false;
1825 }
1826 }
1827 }
1828 return false;
1829 }
1830
1831 boolean visitCompoundType(ClassType ct, Type s, boolean reverse) {
1832 Warner warn = noWarnings;
1833 for (Type c : directSupertypes(ct)) {
1834 warn.clear();
1835 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1836 return false;
1837 }
1838 if (warn.hasLint(LintCategory.UNCHECKED))
1839 warnStack.head.warn(LintCategory.UNCHECKED);
1840 return true;
1841 }
1842
1843 @Override
1844 public Boolean visitArrayType(ArrayType t, Type s) {
1845 switch (s.getTag()) {
1846 case ERROR:
1847 case BOT:
1848 return true;
1849 case TYPEVAR:
1850 if (isCastable(s, t, noWarnings)) {
1851 warnStack.head.warn(LintCategory.UNCHECKED);
1852 return true;
1853 } else {
1854 return false;
1855 }
1856 case CLASS:
1857 return isSubtype(t, s);
1858 case ARRAY:
1859 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1860 return elemtype(t).hasTag(elemtype(s).getTag());
1861 } else {
1862 return isCastable(elemtype(t), elemtype(s), warnStack.head);
1863 }
1864 default:
1865 return false;
1866 }
1867 }
1868
1869 @Override
1870 public Boolean visitTypeVar(TypeVar t, Type s) {
1871 switch (s.getTag()) {
1872 case ERROR:
1873 case BOT:
1874 return true;
1875 case TYPEVAR:
1876 if (isSubtype(t, s)) {
1877 return true;
1878 } else if (isCastable(t.getUpperBound(), s, noWarnings)) {
1879 warnStack.head.warn(LintCategory.UNCHECKED);
1880 return true;
1881 } else {
1882 return false;
1883 }
1884 default:
1885 return isCastable(t.getUpperBound(), s, warnStack.head);
1886 }
1887 }
1888
1889 @Override
1890 public Boolean visitErrorType(ErrorType t, Type s) {
1891 return true;
1892 }
1893 };
1894 // </editor-fold>
1895
1896 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1897 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1898 while (ts.tail != null && ss.tail != null) {
1899 if (disjointType(ts.head, ss.head)) return true;
1900 ts = ts.tail;
1901 ss = ss.tail;
1902 }
1903 return false;
1904 }
1905
1906 /**
1907 * Two types or wildcards are considered disjoint if it can be
1908 * proven that no type can be contained in both. It is
1909 * conservative in that it is allowed to say that two types are
1910 * not disjoint, even though they actually are.
1911 *
1912 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1913 * {@code X} and {@code Y} are not disjoint.
1914 */
1915 public boolean disjointType(Type t, Type s) {
1916 return disjointType.visit(t, s);
1917 }
1918 // where
1919 private TypeRelation disjointType = new TypeRelation() {
1920
1921 private Set<TypePair> cache = new HashSet<>();
1922
1923 @Override
1924 public Boolean visitType(Type t, Type s) {
1925 if (s.hasTag(WILDCARD))
1926 return visit(s, t);
1927 else
1928 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1929 }
1930
1931 private boolean isCastableRecursive(Type t, Type s) {
1932 TypePair pair = new TypePair(t, s);
1933 if (cache.add(pair)) {
1934 try {
1935 return Types.this.isCastable(t, s);
1936 } finally {
1937 cache.remove(pair);
1938 }
1939 } else {
1940 return true;
1941 }
1942 }
1943
1944 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1945 TypePair pair = new TypePair(t, s);
1946 if (cache.add(pair)) {
1947 try {
1948 return Types.this.notSoftSubtype(t, s);
1949 } finally {
1950 cache.remove(pair);
1951 }
1952 } else {
1953 return false;
1954 }
1955 }
1956
1957 @Override
1958 public Boolean visitWildcardType(WildcardType t, Type s) {
1959 if (t.isUnbound())
1960 return false;
1961
1962 if (!s.hasTag(WILDCARD)) {
1963 if (t.isExtendsBound())
1964 return notSoftSubtypeRecursive(s, t.type);
1965 else
1966 return notSoftSubtypeRecursive(t.type, s);
1967 }
1968
1969 if (s.isUnbound())
1970 return false;
1971
1972 if (t.isExtendsBound()) {
1973 if (s.isExtendsBound())
1974 return !isCastableRecursive(t.type, wildUpperBound(s));
1975 else if (s.isSuperBound())
1976 return notSoftSubtypeRecursive(wildLowerBound(s), t.type);
1977 } else if (t.isSuperBound()) {
1978 if (s.isExtendsBound())
1979 return notSoftSubtypeRecursive(t.type, wildUpperBound(s));
1980 }
1981 return false;
1982 }
1983 };
1984 // </editor-fold>
1985
1986 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds">
1987 public List<Type> cvarLowerBounds(List<Type> ts) {
1988 return ts.map(cvarLowerBoundMapping);
1989 }
1990 private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() {
1991 @Override
1992 public Type visitCapturedType(CapturedType t, Void _unused) {
1993 return cvarLowerBound(t);
1994 }
1995 };
1996 // </editor-fold>
1997
1998 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1999 /**
2000 * This relation answers the question: is impossible that
2001 * something of type `t' can be a subtype of `s'? This is
2002 * different from the question "is `t' not a subtype of `s'?"
2003 * when type variables are involved: Integer is not a subtype of T
2004 * where {@code <T extends Number>} but it is not true that Integer cannot
2005 * possibly be a subtype of T.
2006 */
2007 public boolean notSoftSubtype(Type t, Type s) {
2008 if (t == s) return false;
2009 if (t.hasTag(TYPEVAR)) {
2010 TypeVar tv = (TypeVar) t;
2011 return !isCastable(tv.getUpperBound(),
2012 relaxBound(s),
2013 noWarnings);
2014 }
2015 if (!s.hasTag(WILDCARD))
2016 s = cvarUpperBound(s);
2017
2018 return !isSubtype(t, relaxBound(s));
2019 }
2020
2021 private Type relaxBound(Type t) {
2022 return (t.hasTag(TYPEVAR)) ?
2023 rewriteQuantifiers(skipTypeVars(t, false), true, true) :
2024 t;
2025 }
2026 // </editor-fold>
2027
2028 // <editor-fold defaultstate="collapsed" desc="isReifiable">
2029 public boolean isReifiable(Type t) {
2030 return isReifiable.visit(t);
2031 }
2032 // where
2033 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
2034
2035 public Boolean visitType(Type t, Void ignored) {
2036 return true;
2037 }
2038
2039 @Override
2040 public Boolean visitClassType(ClassType t, Void ignored) {
2041 if (t.isCompound())
2042 return false;
2043 else {
2044 if (!t.isParameterized())
2045 return true;
2046
2047 for (Type param : t.allparams()) {
2048 if (!param.isUnbound())
2049 return false;
2050 }
2051 return true;
2052 }
2053 }
2054
2055 @Override
2056 public Boolean visitArrayType(ArrayType t, Void ignored) {
2057 return visit(t.elemtype);
2058 }
2059
2060 @Override
2061 public Boolean visitTypeVar(TypeVar t, Void ignored) {
2062 return false;
2063 }
2064 };
2065 // </editor-fold>
2066
2067 // <editor-fold defaultstate="collapsed" desc="Array Utils">
2068 public boolean isArray(Type t) {
2069 while (t.hasTag(WILDCARD))
2070 t = wildUpperBound(t);
2071 return t.hasTag(ARRAY);
2072 }
2073
2074 /**
2075 * The element type of an array.
2076 */
2077 public Type elemtype(Type t) {
2078 switch (t.getTag()) {
2079 case WILDCARD:
2080 return elemtype(wildUpperBound(t));
2081 case ARRAY:
2082 return ((ArrayType)t).elemtype;
2083 case FORALL:
2084 return elemtype(((ForAll)t).qtype);
2085 case ERROR:
2086 return t;
2087 default:
2088 return null;
2089 }
2090 }
2091
2092 public Type elemtypeOrType(Type t) {
2093 Type elemtype = elemtype(t);
2094 return elemtype != null ?
2095 elemtype :
2096 t;
2097 }
2098
2099 /**
2100 * Mapping to take element type of an arraytype
2101 */
2102 private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() {
2103 @Override
2104 public Type visitArrayType(ArrayType t, Void _unused) {
2105 return t.elemtype;
2106 }
2107
2108 @Override
2109 public Type visitTypeVar(TypeVar t, Void _unused) {
2110 return visit(skipTypeVars(t, false));
2111 }
2112 };
2113
2114 /**
2115 * The number of dimensions of an array type.
2116 */
2117 public int dimensions(Type t) {
2118 int result = 0;
2119 while (t.hasTag(ARRAY)) {
2120 result++;
2121 t = elemtype(t);
2122 }
2123 return result;
2124 }
2125
2126 /**
2127 * Returns an ArrayType with the component type t
2128 *
2129 * @param t The component type of the ArrayType
2130 * @return the ArrayType for the given component
2131 */
2132 public ArrayType makeArrayType(Type t) {
2133 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) {
2134 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
2135 }
2136 return new ArrayType(t, syms.arrayClass);
2137 }
2138 // </editor-fold>
2139
2140 // <editor-fold defaultstate="collapsed" desc="asSuper">
2141 /**
2142 * Return the (most specific) base type of t that starts with the
2143 * given symbol. If none exists, return null.
2144 *
2145 * Caveat Emptor: Since javac represents the class of all arrays with a singleton
2146 * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant,
2147 * this method could yield surprising answers when invoked on arrays. For example when
2148 * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null.
2149 *
2150 * @param t a type
2151 * @param sym a symbol
2152 */
2153 public Type asSuper(Type t, Symbol sym) {
2154 /* Some examples:
2155 *
2156 * (Enum<E>, Comparable) => Comparable<E>
2157 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind>
2158 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree
2159 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) =>
2160 * Iterable<capture#160 of ? extends c.s.s.d.DocTree>
2161 */
2162 if (sym.type == syms.objectType) { //optimization
2163 return syms.objectType;
2164 }
2165 return asSuper.visit(t, sym);
2166 }
2167 // where
2168 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
2169
2170 private Set<Symbol> seenTypes = new HashSet<>();
2171
2172 public Type visitType(Type t, Symbol sym) {
2173 return null;
2174 }
2175
2176 @Override
2177 public Type visitClassType(ClassType t, Symbol sym) {
2178 if (t.tsym == sym)
2179 return t;
2180
2181 Symbol c = t.tsym;
2182 if (!seenTypes.add(c)) {
2183 return null;
2184 }
2185 try {
2186 Type st = supertype(t);
2187 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) {
2188 Type x = asSuper(st, sym);
2189 if (x != null)
2190 return x;
2191 }
2192 if ((sym.flags() & INTERFACE) != 0) {
2193 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
2194 if (!l.head.hasTag(ERROR)) {
2195 Type x = asSuper(l.head, sym);
2196 if (x != null)
2197 return x;
2198 }
2199 }
2200 }
2201 return null;
2202 } finally {
2203 seenTypes.remove(c);
2204 }
2205 }
2206
2207 @Override
2208 public Type visitArrayType(ArrayType t, Symbol sym) {
2209 return isSubtype(t, sym.type) ? sym.type : null;
2210 }
2211
2212 @Override
2213 public Type visitTypeVar(TypeVar t, Symbol sym) {
2214 if (t.tsym == sym)
2215 return t;
2216 else
2217 return asSuper(t.getUpperBound(), sym);
2218 }
2219
2220 @Override
2221 public Type visitErrorType(ErrorType t, Symbol sym) {
2222 return t;
2223 }
2224 };
2225
2226 /**
2227 * Return the base type of t or any of its outer types that starts
2228 * with the given symbol. If none exists, return null.
2229 *
2230 * @param t a type
2231 * @param sym a symbol
2232 */
2233 public Type asOuterSuper(Type t, Symbol sym) {
2234 switch (t.getTag()) {
2235 case CLASS:
2236 do {
2237 Type s = asSuper(t, sym);
2238 if (s != null) return s;
2239 t = t.getEnclosingType();
2240 } while (t.hasTag(CLASS));
2241 return null;
2242 case ARRAY:
2243 return isSubtype(t, sym.type) ? sym.type : null;
2244 case TYPEVAR:
2245 return asSuper(t, sym);
2246 case ERROR:
2247 return t;
2248 default:
2249 return null;
2250 }
2251 }
2252
2253 /**
2254 * Return the base type of t or any of its enclosing types that
2255 * starts with the given symbol. If none exists, return null.
2256 *
2257 * @param t a type
2258 * @param sym a symbol
2259 */
2260 public Type asEnclosingSuper(Type t, Symbol sym) {
2261 switch (t.getTag()) {
2262 case CLASS:
2263 do {
2264 Type s = asSuper(t, sym);
2265 if (s != null) return s;
2266 Type outer = t.getEnclosingType();
2267 t = (outer.hasTag(CLASS)) ? outer :
2268 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
2269 Type.noType;
2270 } while (t.hasTag(CLASS));
2271 return null;
2272 case ARRAY:
2273 return isSubtype(t, sym.type) ? sym.type : null;
2274 case TYPEVAR:
2275 return asSuper(t, sym);
2276 case ERROR:
2277 return t;
2278 default:
2279 return null;
2280 }
2281 }
2282 // </editor-fold>
2283
2284 // <editor-fold defaultstate="collapsed" desc="memberType">
2285 /**
2286 * The type of given symbol, seen as a member of t.
2287 *
2288 * @param t a type
2289 * @param sym a symbol
2290 */
2291 public Type memberType(Type t, Symbol sym) {
2292 return (sym.flags() & STATIC) != 0
2293 ? sym.type
2294 : memberType.visit(t, sym);
2295 }
2296 // where
2297 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
2298
2299 public Type visitType(Type t, Symbol sym) {
2300 return sym.type;
2301 }
2302
2303 @Override
2304 public Type visitWildcardType(WildcardType t, Symbol sym) {
2305 return memberType(wildUpperBound(t), sym);
2306 }
2307
2308 @Override
2309 public Type visitClassType(ClassType t, Symbol sym) {
2310 Symbol owner = sym.owner;
2311 long flags = sym.flags();
2312 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
2313 Type base = asOuterSuper(t, owner);
2314 //if t is an intersection type T = CT & I1 & I2 ... & In
2315 //its supertypes CT, I1, ... In might contain wildcards
2316 //so we need to go through capture conversion
2317 base = t.isCompound() ? capture(base) : base;
2318 if (base != null) {
2319 List<Type> ownerParams = owner.type.allparams();
2320 List<Type> baseParams = base.allparams();
2321 if (ownerParams.nonEmpty()) {
2322 if (baseParams.isEmpty()) {
2323 // then base is a raw type
2324 return erasure(sym.type);
2325 } else {
2326 return subst(sym.type, ownerParams, baseParams);
2327 }
2328 }
2329 }
2330 }
2331 return sym.type;
2332 }
2333
2334 @Override
2335 public Type visitTypeVar(TypeVar t, Symbol sym) {
2336 return memberType(t.getUpperBound(), sym);
2337 }
2338
2339 @Override
2340 public Type visitErrorType(ErrorType t, Symbol sym) {
2341 return t;
2342 }
2343 };
2344 // </editor-fold>
2345
2346 // <editor-fold defaultstate="collapsed" desc="isAssignable">
2347 public boolean isAssignable(Type t, Type s) {
2348 return isAssignable(t, s, noWarnings);
2349 }
2350
2351 /**
2352 * Is t assignable to s?<br>
2353 * Equivalent to subtype except for constant values and raw
2354 * types.<br>
2355 * (not defined for Method and ForAll types)
2356 */
2357 public boolean isAssignable(Type t, Type s, Warner warn) {
2358 if (t.hasTag(ERROR))
2359 return true;
2360 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) {
2361 int value = ((Number)t.constValue()).intValue();
2362 switch (s.getTag()) {
2363 case BYTE:
2364 case CHAR:
2365 case SHORT:
2366 case INT:
2367 if (s.getTag().checkRange(value))
2368 return true;
2369 break;
2370 case CLASS:
2371 switch (unboxedType(s).getTag()) {
2372 case BYTE:
2373 case CHAR:
2374 case SHORT:
2375 return isAssignable(t, unboxedType(s), warn);
2376 }
2377 break;
2378 }
2379 }
2380 return isConvertible(t, s, warn);
2381 }
2382 // </editor-fold>
2383
2384 // <editor-fold defaultstate="collapsed" desc="erasure">
2385 /**
2386 * The erasure of t {@code |t|} -- the type that results when all
2387 * type parameters in t are deleted.
2388 */
2389 public Type erasure(Type t) {
2390 return eraseNotNeeded(t) ? t : erasure(t, false);
2391 }
2392 //where
2393 private boolean eraseNotNeeded(Type t) {
2394 // We don't want to erase primitive types and String type as that
2395 // operation is idempotent. Also, erasing these could result in loss
2396 // of information such as constant values attached to such types.
2397 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2398 }
2399
2400 private Type erasure(Type t, boolean recurse) {
2401 if (t.isPrimitive()) {
2402 return t; /* fast special case */
2403 } else {
2404 Type out = erasure.visit(t, recurse);
2405 return out;
2406 }
2407 }
2408 // where
2409 private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() {
2410 @SuppressWarnings("fallthrough")
2411 private Type combineMetadata(final Type s,
2412 final Type t) {
2413 if (t.getMetadata().nonEmpty()) {
2414 switch (s.getTag()) {
2415 case CLASS:
2416 if (s instanceof UnionClassType ||
2417 s instanceof IntersectionClassType) {
2418 return s;
2419 }
2420 //fall-through
2421 case BYTE, CHAR, SHORT, LONG, FLOAT, INT, DOUBLE, BOOLEAN,
2422 ARRAY, MODULE, TYPEVAR, WILDCARD, BOT:
2423 return s.dropMetadata(Annotations.class);
2424 case VOID, METHOD, PACKAGE, FORALL, DEFERRED,
2425 NONE, ERROR, UNKNOWN, UNDETVAR, UNINITIALIZED_THIS,
2426 UNINITIALIZED_OBJECT:
2427 return s;
2428 default:
2429 throw new AssertionError(s.getTag().name());
2430 }
2431 } else {
2432 return s;
2433 }
2434 }
2435
2436 public Type visitType(Type t, Boolean recurse) {
2437 if (t.isPrimitive())
2438 return t; /*fast special case*/
2439 else {
2440 //other cases already handled
2441 return combineMetadata(t, t);
2442 }
2443 }
2444
2445 @Override
2446 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2447 Type erased = erasure(wildUpperBound(t), recurse);
2448 return combineMetadata(erased, t);
2449 }
2450
2451 @Override
2452 public Type visitClassType(ClassType t, Boolean recurse) {
2453 Type erased = t.tsym.erasure(Types.this);
2454 if (recurse) {
2455 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym,
2456 t.dropMetadata(Annotations.class).getMetadata());
2457 return erased;
2458 } else {
2459 return combineMetadata(erased, t);
2460 }
2461 }
2462
2463 @Override
2464 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2465 Type erased = erasure(t.getUpperBound(), recurse);
2466 return combineMetadata(erased, t);
2467 }
2468 };
2469
2470 public List<Type> erasure(List<Type> ts) {
2471 return erasure.visit(ts, false);
2472 }
2473
2474 public Type erasureRecursive(Type t) {
2475 return erasure(t, true);
2476 }
2477
2478 public List<Type> erasureRecursive(List<Type> ts) {
2479 return erasure.visit(ts, true);
2480 }
2481 // </editor-fold>
2482
2483 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType">
2484 /**
2485 * Make an intersection type from non-empty list of types. The list should be ordered according to
2486 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion.
2487 * Hence, this version of makeIntersectionType may not be called during a classfile read.
2488 *
2489 * @param bounds the types from which the intersection type is formed
2490 */
2491 public IntersectionClassType makeIntersectionType(List<Type> bounds) {
2492 return makeIntersectionType(bounds, bounds.head.tsym.isInterface());
2493 }
2494
2495 /**
2496 * Make an intersection type from non-empty list of types. The list should be ordered according to
2497 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as
2498 * an extra parameter indicates as to whether all bounds are interfaces - in which case the
2499 * supertype is implicitly assumed to be 'Object'.
2500 *
2501 * @param bounds the types from which the intersection type is formed
2502 * @param allInterfaces are all bounds interface types?
2503 */
2504 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) {
2505 Assert.check(bounds.nonEmpty());
2506 Type firstExplicitBound = bounds.head;
2507 if (allInterfaces) {
2508 bounds = bounds.prepend(syms.objectType);
2509 }
2510 ClassSymbol bc =
2511 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2512 Type.moreInfo
2513 ? names.fromString(bounds.toString())
2514 : names.empty,
2515 null,
2516 syms.noSymbol);
2517 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces);
2518 bc.type = intersectionType;
2519 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
2520 syms.objectType : // error condition, recover
2521 erasure(firstExplicitBound);
2522 bc.members_field = WriteableScope.create(bc);
2523 return intersectionType;
2524 }
2525 // </editor-fold>
2526
2527 // <editor-fold defaultstate="collapsed" desc="supertype">
2528 public Type supertype(Type t) {
2529 return supertype.visit(t);
2530 }
2531 // where
2532 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2533
2534 public Type visitType(Type t, Void ignored) {
2535 // A note on wildcards: there is no good way to
2536 // determine a supertype for a lower-bounded wildcard.
2537 return Type.noType;
2538 }
2539
2540 @Override
2541 public Type visitClassType(ClassType t, Void ignored) {
2542 if (t.supertype_field == null) {
2543 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2544 // An interface has no superclass; its supertype is Object.
2545 if (t.isInterface())
2546 supertype = ((ClassType)t.tsym.type).supertype_field;
2547 if (t.supertype_field == null) {
2548 List<Type> actuals = classBound(t).allparams();
2549 List<Type> formals = t.tsym.type.allparams();
2550 if (t.hasErasedSupertypes()) {
2551 t.supertype_field = erasureRecursive(supertype);
2552 } else if (formals.nonEmpty()) {
2553 t.supertype_field = subst(supertype, formals, actuals);
2554 }
2555 else {
2556 t.supertype_field = supertype;
2557 }
2558 }
2559 }
2560 return t.supertype_field;
2561 }
2562
2563 /**
2564 * The supertype is always a class type. If the type
2565 * variable's bounds start with a class type, this is also
2566 * the supertype. Otherwise, the supertype is
2567 * java.lang.Object.
2568 */
2569 @Override
2570 public Type visitTypeVar(TypeVar t, Void ignored) {
2571 if (t.getUpperBound().hasTag(TYPEVAR) ||
2572 (!t.getUpperBound().isCompound() && !t.getUpperBound().isInterface())) {
2573 return t.getUpperBound();
2574 } else {
2575 return supertype(t.getUpperBound());
2576 }
2577 }
2578
2579 @Override
2580 public Type visitArrayType(ArrayType t, Void ignored) {
2581 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2582 return arraySuperType();
2583 else
2584 return new ArrayType(supertype(t.elemtype), t.tsym);
2585 }
2586
2587 @Override
2588 public Type visitErrorType(ErrorType t, Void ignored) {
2589 return Type.noType;
2590 }
2591 };
2592 // </editor-fold>
2593
2594 // <editor-fold defaultstate="collapsed" desc="interfaces">
2595 /**
2596 * Return the interfaces implemented by this class.
2597 */
2598 public List<Type> interfaces(Type t) {
2599 return interfaces.visit(t);
2600 }
2601 // where
2602 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2603
2604 public List<Type> visitType(Type t, Void ignored) {
2605 return List.nil();
2606 }
2607
2608 @Override
2609 public List<Type> visitClassType(ClassType t, Void ignored) {
2610 if (t.interfaces_field == null) {
2611 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2612 if (t.interfaces_field == null) {
2613 // If t.interfaces_field is null, then t must
2614 // be a parameterized type (not to be confused
2615 // with a generic type declaration).
2616 // Terminology:
2617 // Parameterized type: List<String>
2618 // Generic type declaration: class List<E> { ... }
2619 // So t corresponds to List<String> and
2620 // t.tsym.type corresponds to List<E>.
2621 // The reason t must be parameterized type is
2622 // that completion will happen as a side
2623 // effect of calling
2624 // ClassSymbol.getInterfaces. Since
2625 // t.interfaces_field is null after
2626 // completion, we can assume that t is not the
2627 // type of a class/interface declaration.
2628 Assert.check(t != t.tsym.type, t);
2629 List<Type> actuals = t.allparams();
2630 List<Type> formals = t.tsym.type.allparams();
2631 if (t.hasErasedSupertypes()) {
2632 t.interfaces_field = erasureRecursive(interfaces);
2633 } else if (formals.nonEmpty()) {
2634 t.interfaces_field = subst(interfaces, formals, actuals);
2635 }
2636 else {
2637 t.interfaces_field = interfaces;
2638 }
2639 }
2640 }
2641 return t.interfaces_field;
2642 }
2643
2644 @Override
2645 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2646 if (t.getUpperBound().isCompound())
2647 return interfaces(t.getUpperBound());
2648
2649 if (t.getUpperBound().isInterface())
2650 return List.of(t.getUpperBound());
2651
2652 return List.nil();
2653 }
2654 };
2655
2656 public List<Type> directSupertypes(Type t) {
2657 return directSupertypes.visit(t);
2658 }
2659 // where
2660 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() {
2661
2662 public List<Type> visitType(final Type type, final Void ignored) {
2663 if (!type.isIntersection()) {
2664 final Type sup = supertype(type);
2665 return (sup == Type.noType || sup == type || sup == null)
2666 ? interfaces(type)
2667 : interfaces(type).prepend(sup);
2668 } else {
2669 return ((IntersectionClassType)type).getExplicitComponents();
2670 }
2671 }
2672 };
2673
2674 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2675 for (Type i2 : interfaces(origin.type)) {
2676 if (isym == i2.tsym) return true;
2677 }
2678 return false;
2679 }
2680 // </editor-fold>
2681
2682 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2683 Map<Type,Boolean> isDerivedRawCache = new HashMap<>();
2684
2685 public boolean isDerivedRaw(Type t) {
2686 Boolean result = isDerivedRawCache.get(t);
2687 if (result == null) {
2688 result = isDerivedRawInternal(t);
2689 isDerivedRawCache.put(t, result);
2690 }
2691 return result;
2692 }
2693
2694 public boolean isDerivedRawInternal(Type t) {
2695 if (t.isErroneous())
2696 return false;
2697 return
2698 t.isRaw() ||
2699 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) ||
2700 isDerivedRaw(interfaces(t));
2701 }
2702
2703 public boolean isDerivedRaw(List<Type> ts) {
2704 List<Type> l = ts;
2705 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2706 return l.nonEmpty();
2707 }
2708 // </editor-fold>
2709
2710 // <editor-fold defaultstate="collapsed" desc="setBounds">
2711 /**
2712 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly,
2713 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise
2714 * the supertype is simply left null (in this case, the supertype is assumed to be the head of
2715 * the bound list passed as second argument). Note that this check might cause a symbol completion.
2716 * Hence, this version of setBounds may not be called during a classfile read.
2717 *
2718 * @param t a type variable
2719 * @param bounds the bounds, must be nonempty
2720 */
2721 public void setBounds(TypeVar t, List<Type> bounds) {
2722 setBounds(t, bounds, bounds.head.tsym.isInterface());
2723 }
2724
2725 /**
2726 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds.
2727 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds
2728 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'.
2729 *
2730 * @param t a type variable
2731 * @param bounds the bounds, must be nonempty
2732 * @param allInterfaces are all bounds interface types?
2733 */
2734 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2735 t.setUpperBound( bounds.tail.isEmpty() ?
2736 bounds.head :
2737 makeIntersectionType(bounds, allInterfaces) );
2738 t.rank_field = -1;
2739 }
2740 // </editor-fold>
2741
2742 // <editor-fold defaultstate="collapsed" desc="getBounds">
2743 /**
2744 * Return list of bounds of the given type variable.
2745 */
2746 public List<Type> getBounds(TypeVar t) {
2747 if (t.getUpperBound().hasTag(NONE))
2748 return List.nil();
2749 else if (t.getUpperBound().isErroneous() || !t.getUpperBound().isCompound())
2750 return List.of(t.getUpperBound());
2751 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2752 return interfaces(t).prepend(supertype(t));
2753 else
2754 // No superclass was given in bounds.
2755 // In this case, supertype is Object, erasure is first interface.
2756 return interfaces(t);
2757 }
2758 // </editor-fold>
2759
2760 // <editor-fold defaultstate="collapsed" desc="classBound">
2761 /**
2762 * If the given type is a (possibly selected) type variable,
2763 * return the bounding class of this type, otherwise return the
2764 * type itself.
2765 */
2766 public Type classBound(Type t) {
2767 return classBound.visit(t);
2768 }
2769 // where
2770 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2771
2772 public Type visitType(Type t, Void ignored) {
2773 return t;
2774 }
2775
2776 @Override
2777 public Type visitClassType(ClassType t, Void ignored) {
2778 Type outer1 = classBound(t.getEnclosingType());
2779 if (outer1 != t.getEnclosingType())
2780 return new ClassType(outer1, t.getTypeArguments(), t.tsym,
2781 t.getMetadata());
2782 else
2783 return t;
2784 }
2785
2786 @Override
2787 public Type visitTypeVar(TypeVar t, Void ignored) {
2788 return classBound(supertype(t));
2789 }
2790
2791 @Override
2792 public Type visitErrorType(ErrorType t, Void ignored) {
2793 return t;
2794 }
2795 };
2796 // </editor-fold>
2797
2798 // <editor-fold defaultstate="collapsed" desc="subsignature / override equivalence">
2799 /**
2800 * Returns true iff the first signature is a <em>subsignature</em>
2801 * of the other. This is <b>not</b> an equivalence
2802 * relation.
2803 *
2804 * @jls 8.4.2 Method Signature
2805 * @see #overrideEquivalent(Type t, Type s)
2806 * @param t first signature (possibly raw).
2807 * @param s second signature (could be subjected to erasure).
2808 * @return true if t is a subsignature of s.
2809 */
2810 public boolean isSubSignature(Type t, Type s) {
2811 return hasSameArgs(t, s, true) || hasSameArgs(t, erasure(s), true);
2812 }
2813
2814 /**
2815 * Returns true iff these signatures are related by <em>override
2816 * equivalence</em>. This is the natural extension of
2817 * isSubSignature to an equivalence relation.
2818 *
2819 * @jls 8.4.2 Method Signature
2820 * @see #isSubSignature(Type t, Type s)
2821 * @param t a signature (possible raw, could be subjected to
2822 * erasure).
2823 * @param s a signature (possible raw, could be subjected to
2824 * erasure).
2825 * @return true if either argument is a subsignature of the other.
2826 */
2827 public boolean overrideEquivalent(Type t, Type s) {
2828 return hasSameArgs(t, s) ||
2829 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2830 }
2831
2832 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2833 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) {
2834 if (msym.overrides(sym, origin, Types.this, true)) {
2835 return true;
2836 }
2837 }
2838 return false;
2839 }
2840
2841 /**
2842 * This enum defines the strategy for implementing most specific return type check
2843 * during the most specific and functional interface checks.
2844 */
2845 public enum MostSpecificReturnCheck {
2846 /**
2847 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling
2848 * method type variables (if either method is generic) and (ii) subtyping should be replaced
2849 * by type-equivalence for primitives. This is essentially an inlined version of
2850 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been
2851 * replaced with a strict subtyping check.
2852 */
2853 BASIC() {
2854 @Override
2855 public boolean test(Type mt1, Type mt2, Types types) {
2856 List<Type> tvars = mt1.getTypeArguments();
2857 List<Type> svars = mt2.getTypeArguments();
2858 Type t = mt1.getReturnType();
2859 Type s = types.subst(mt2.getReturnType(), svars, tvars);
2860 return types.isSameType(t, s) ||
2861 !t.isPrimitive() &&
2862 !s.isPrimitive() &&
2863 types.isSubtype(t, s);
2864 }
2865 },
2866 /**
2867 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2.
2868 */
2869 RTS() {
2870 @Override
2871 public boolean test(Type mt1, Type mt2, Types types) {
2872 return types.returnTypeSubstitutable(mt1, mt2);
2873 }
2874 };
2875
2876 public abstract boolean test(Type mt1, Type mt2, Types types);
2877 }
2878
2879 /**
2880 * Merge multiple abstract methods. The preferred method is a method that is a subsignature
2881 * of all the other signatures and whose return type is more specific {@link MostSpecificReturnCheck}.
2882 * The resulting preferred method has a throws clause that is the intersection of the merged
2883 * methods' clauses.
2884 */
2885 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) {
2886 //first check for preconditions
2887 boolean shouldErase = false;
2888 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes();
2889 for (Symbol s : ambiguousInOrder) {
2890 if ((s.flags() & ABSTRACT) == 0 ||
2891 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) {
2892 return Optional.empty();
2893 } else if (s.type.hasTag(FORALL)) {
2894 shouldErase = true;
2895 }
2896 }
2897 //then merge abstracts
2898 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) {
2899 outer: for (Symbol s : ambiguousInOrder) {
2900 Type mt = memberType(site, s);
2901 List<Type> allThrown = mt.getThrownTypes();
2902 for (Symbol s2 : ambiguousInOrder) {
2903 if (s != s2) {
2904 Type mt2 = memberType(site, s2);
2905 if (!isSubSignature(mt, mt2) ||
2906 !mostSpecificReturnCheck.test(mt, mt2, this)) {
2907 //ambiguity cannot be resolved
2908 continue outer;
2909 } else {
2910 List<Type> thrownTypes2 = mt2.getThrownTypes();
2911 if (!mt.hasTag(FORALL) && shouldErase) {
2912 thrownTypes2 = erasure(thrownTypes2);
2913 } else if (mt.hasTag(FORALL)) {
2914 //subsignature implies that if most specific is generic, then all other
2915 //methods are too
2916 Assert.check(mt2.hasTag(FORALL));
2917 // if both are generic methods, adjust thrown types ahead of intersection computation
2918 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments());
2919 }
2920 allThrown = chk.intersect(allThrown, thrownTypes2);
2921 }
2922 }
2923 }
2924 return (allThrown == mt.getThrownTypes()) ?
2925 Optional.of(s) :
2926 Optional.of(new MethodSymbol(
2927 s.flags(),
2928 s.name,
2929 createMethodTypeWithThrown(s.type, allThrown),
2930 s.owner) {
2931 @Override
2932 public Symbol baseSymbol() {
2933 return s;
2934 }
2935 });
2936 }
2937 }
2938 return Optional.empty();
2939 }
2940
2941 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2942 class ImplementationCache {
2943
2944 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>();
2945
2946 class Entry {
2947 final MethodSymbol cachedImpl;
2948 final Predicate<Symbol> implFilter;
2949 final boolean checkResult;
2950 final int prevMark;
2951
2952 public Entry(MethodSymbol cachedImpl,
2953 Predicate<Symbol> scopeFilter,
2954 boolean checkResult,
2955 int prevMark) {
2956 this.cachedImpl = cachedImpl;
2957 this.implFilter = scopeFilter;
2958 this.checkResult = checkResult;
2959 this.prevMark = prevMark;
2960 }
2961
2962 boolean matches(Predicate<Symbol> scopeFilter, boolean checkResult, int mark) {
2963 return this.implFilter == scopeFilter &&
2964 this.checkResult == checkResult &&
2965 this.prevMark == mark;
2966 }
2967 }
2968
2969 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2970 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2971 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2972 if (cache == null) {
2973 cache = new HashMap<>();
2974 _map.put(ms, new SoftReference<>(cache));
2975 }
2976 Entry e = cache.get(origin);
2977 CompoundScope members = membersClosure(origin.type, true);
2978 if (e == null ||
2979 !e.matches(implFilter, checkResult, members.getMark())) {
2980 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2981 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2982 return impl;
2983 }
2984 else {
2985 return e.cachedImpl;
2986 }
2987 }
2988
2989 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2990 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
2991 t = skipTypeVars(t, false);
2992 TypeSymbol c = t.tsym;
2993 Symbol bestSoFar = null;
2994 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) {
2995 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) {
2996 bestSoFar = sym;
2997 if ((sym.flags() & ABSTRACT) == 0) {
2998 //if concrete impl is found, exit immediately
2999 break;
3000 }
3001 }
3002 }
3003 if (bestSoFar != null) {
3004 //return either the (only) concrete implementation or the first abstract one
3005 return (MethodSymbol)bestSoFar;
3006 }
3007 }
3008 return null;
3009 }
3010 }
3011
3012 private ImplementationCache implCache = new ImplementationCache();
3013
3014 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
3015 return implCache.get(ms, origin, checkResult, implFilter);
3016 }
3017 // </editor-fold>
3018
3019 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
3020 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> {
3021
3022 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>();
3023
3024 Set<TypeSymbol> seenTypes = new HashSet<>();
3025
3026 class MembersScope extends CompoundScope {
3027
3028 CompoundScope scope;
3029
3030 public MembersScope(CompoundScope scope) {
3031 super(scope.owner);
3032 this.scope = scope;
3033 }
3034
3035 Predicate<Symbol> combine(Predicate<Symbol> sf) {
3036 return s -> !s.owner.isInterface() && (sf == null || sf.test(s));
3037 }
3038
3039 @Override
3040 public Iterable<Symbol> getSymbols(Predicate<Symbol> sf, LookupKind lookupKind) {
3041 return scope.getSymbols(combine(sf), lookupKind);
3042 }
3043
3044 @Override
3045 public Iterable<Symbol> getSymbolsByName(Name name, Predicate<Symbol> sf, LookupKind lookupKind) {
3046 return scope.getSymbolsByName(name, combine(sf), lookupKind);
3047 }
3048
3049 @Override
3050 public int getMark() {
3051 return scope.getMark();
3052 }
3053 }
3054
3055 CompoundScope nilScope;
3056
3057 /** members closure visitor methods **/
3058
3059 public CompoundScope visitType(Type t, Void _unused) {
3060 if (nilScope == null) {
3061 nilScope = new CompoundScope(syms.noSymbol);
3062 }
3063 return nilScope;
3064 }
3065
3066 @Override
3067 public CompoundScope visitClassType(ClassType t, Void _unused) {
3068 if (!seenTypes.add(t.tsym)) {
3069 //this is possible when an interface is implemented in multiple
3070 //superclasses, or when a class hierarchy is circular - in such
3071 //cases we don't need to recurse (empty scope is returned)
3072 return new CompoundScope(t.tsym);
3073 }
3074 try {
3075 seenTypes.add(t.tsym);
3076 ClassSymbol csym = (ClassSymbol)t.tsym;
3077 CompoundScope membersClosure = _map.get(csym);
3078 if (membersClosure == null) {
3079 membersClosure = new CompoundScope(csym);
3080 for (Type i : interfaces(t)) {
3081 membersClosure.prependSubScope(visit(i, null));
3082 }
3083 membersClosure.prependSubScope(visit(supertype(t), null));
3084 membersClosure.prependSubScope(csym.members());
3085 _map.put(csym, membersClosure);
3086 }
3087 return membersClosure;
3088 }
3089 finally {
3090 seenTypes.remove(t.tsym);
3091 }
3092 }
3093
3094 @Override
3095 public CompoundScope visitTypeVar(TypeVar t, Void _unused) {
3096 return visit(t.getUpperBound(), null);
3097 }
3098 }
3099
3100 private MembersClosureCache membersCache = new MembersClosureCache();
3101
3102 public CompoundScope membersClosure(Type site, boolean skipInterface) {
3103 CompoundScope cs = membersCache.visit(site, null);
3104 Assert.checkNonNull(cs, () -> "type " + site);
3105 return skipInterface ? membersCache.new MembersScope(cs) : cs;
3106 }
3107 // </editor-fold>
3108
3109
3110 /** Return first abstract member of class `sym'.
3111 */
3112 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) {
3113 try {
3114 return firstUnimplementedAbstractImpl(sym, sym);
3115 } catch (CompletionFailure ex) {
3116 chk.completionError(enter.getEnv(sym).tree.pos(), ex);
3117 return null;
3118 }
3119 }
3120 //where:
3121 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) {
3122 MethodSymbol undef = null;
3123 // Do not bother to search in classes that are not abstract,
3124 // since they cannot have abstract members.
3125 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
3126 Scope s = c.members();
3127 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
3128 if (sym.kind == MTH &&
3129 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
3130 MethodSymbol absmeth = (MethodSymbol)sym;
3131 MethodSymbol implmeth = absmeth.implementation(impl, this, true);
3132 if (implmeth == null || implmeth == absmeth) {
3133 //look for default implementations
3134 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head;
3135 if (prov != null && prov.overrides(absmeth, impl, this, true)) {
3136 implmeth = prov;
3137 }
3138 }
3139 if (implmeth == null || implmeth == absmeth) {
3140 undef = absmeth;
3141 break;
3142 }
3143 }
3144 }
3145 if (undef == null) {
3146 Type st = supertype(c.type);
3147 if (st.hasTag(CLASS))
3148 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym);
3149 }
3150 for (List<Type> l = interfaces(c.type);
3151 undef == null && l.nonEmpty();
3152 l = l.tail) {
3153 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym);
3154 }
3155 }
3156 return undef;
3157 }
3158
3159 public class CandidatesCache {
3160 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>();
3161
3162 class Entry {
3163 Type site;
3164 MethodSymbol msym;
3165
3166 Entry(Type site, MethodSymbol msym) {
3167 this.site = site;
3168 this.msym = msym;
3169 }
3170
3171 @Override
3172 public boolean equals(Object obj) {
3173 return (obj instanceof Entry entry)
3174 && entry.msym == msym
3175 && isSameType(site, entry.site);
3176 }
3177
3178 @Override
3179 public int hashCode() {
3180 return Types.this.hashCode(site) & ~msym.hashCode();
3181 }
3182 }
3183
3184 public List<MethodSymbol> get(Entry e) {
3185 return cache.get(e);
3186 }
3187
3188 public void put(Entry e, List<MethodSymbol> msymbols) {
3189 cache.put(e, msymbols);
3190 }
3191 }
3192
3193 public CandidatesCache candidatesCache = new CandidatesCache();
3194
3195 //where
3196 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
3197 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms);
3198 List<MethodSymbol> candidates = candidatesCache.get(e);
3199 if (candidates == null) {
3200 Predicate<Symbol> filter = new MethodFilter(ms, site);
3201 List<MethodSymbol> candidates2 = List.nil();
3202 for (Symbol s : membersClosure(site, false).getSymbols(filter)) {
3203 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
3204 return List.of((MethodSymbol)s);
3205 } else if (!candidates2.contains(s)) {
3206 candidates2 = candidates2.prepend((MethodSymbol)s);
3207 }
3208 }
3209 candidates = prune(candidates2);
3210 candidatesCache.put(e, candidates);
3211 }
3212 return candidates;
3213 }
3214
3215 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
3216 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>();
3217 for (MethodSymbol m1 : methods) {
3218 boolean isMin_m1 = true;
3219 for (MethodSymbol m2 : methods) {
3220 if (m1 == m2) continue;
3221 if (m2.owner != m1.owner &&
3222 asSuper(m2.owner.type, m1.owner) != null) {
3223 isMin_m1 = false;
3224 break;
3225 }
3226 }
3227 if (isMin_m1)
3228 methodsMin.append(m1);
3229 }
3230 return methodsMin.toList();
3231 }
3232 // where
3233 private class MethodFilter implements Predicate<Symbol> {
3234
3235 Symbol msym;
3236 Type site;
3237
3238 MethodFilter(Symbol msym, Type site) {
3239 this.msym = msym;
3240 this.site = site;
3241 }
3242
3243 @Override
3244 public boolean test(Symbol s) {
3245 return s.kind == MTH &&
3246 s.name == msym.name &&
3247 (s.flags() & SYNTHETIC) == 0 &&
3248 s.isInheritedIn(site.tsym, Types.this) &&
3249 overrideEquivalent(memberType(site, s), memberType(site, msym));
3250 }
3251 }
3252 // </editor-fold>
3253
3254 /**
3255 * Does t have the same arguments as s? It is assumed that both
3256 * types are (possibly polymorphic) method types. Monomorphic
3257 * method types "have the same arguments", if their argument lists
3258 * are equal. Polymorphic method types "have the same arguments",
3259 * if they have the same arguments after renaming all type
3260 * variables of one to corresponding type variables in the other,
3261 * where correspondence is by position in the type parameter list.
3262 */
3263 public boolean hasSameArgs(Type t, Type s) {
3264 return hasSameArgs(t, s, true);
3265 }
3266
3267 public boolean hasSameArgs(Type t, Type s, boolean strict) {
3268 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
3269 }
3270
3271 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
3272 return hasSameArgs.visit(t, s);
3273 }
3274 // where
3275 private class HasSameArgs extends TypeRelation {
3276
3277 boolean strict;
3278
3279 public HasSameArgs(boolean strict) {
3280 this.strict = strict;
3281 }
3282
3283 public Boolean visitType(Type t, Type s) {
3284 throw new AssertionError();
3285 }
3286
3287 @Override
3288 public Boolean visitMethodType(MethodType t, Type s) {
3289 return s.hasTag(METHOD)
3290 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
3291 }
3292
3293 @Override
3294 public Boolean visitForAll(ForAll t, Type s) {
3295 if (!s.hasTag(FORALL))
3296 return strict ? false : visitMethodType(t.asMethodType(), s);
3297
3298 ForAll forAll = (ForAll)s;
3299 return hasSameBounds(t, forAll)
3300 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
3301 }
3302
3303 @Override
3304 public Boolean visitErrorType(ErrorType t, Type s) {
3305 return false;
3306 }
3307 }
3308
3309 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
3310 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
3311
3312 // </editor-fold>
3313
3314 // <editor-fold defaultstate="collapsed" desc="subst">
3315 public List<Type> subst(List<Type> ts,
3316 List<Type> from,
3317 List<Type> to) {
3318 return ts.map(new Subst(from, to));
3319 }
3320
3321 /**
3322 * Substitute all occurrences of a type in `from' with the
3323 * corresponding type in `to' in 't'. Match lists `from' and `to'
3324 * from the right: If lists have different length, discard leading
3325 * elements of the longer list.
3326 */
3327 public Type subst(Type t, List<Type> from, List<Type> to) {
3328 return t.map(new Subst(from, to));
3329 }
3330
3331 private class Subst extends StructuralTypeMapping<Void> {
3332 List<Type> from;
3333 List<Type> to;
3334
3335 public Subst(List<Type> from, List<Type> to) {
3336 int fromLength = from.length();
3337 int toLength = to.length();
3338 while (fromLength > toLength) {
3339 fromLength--;
3340 from = from.tail;
3341 }
3342 while (fromLength < toLength) {
3343 toLength--;
3344 to = to.tail;
3345 }
3346 this.from = from;
3347 this.to = to;
3348 }
3349
3350 @Override
3351 public Type visitTypeVar(TypeVar t, Void ignored) {
3352 for (List<Type> from = this.from, to = this.to;
3353 from.nonEmpty();
3354 from = from.tail, to = to.tail) {
3355 if (t.equalsIgnoreMetadata(from.head)) {
3356 return to.head.withTypeVar(t);
3357 }
3358 }
3359 return t;
3360 }
3361
3362 @Override
3363 public Type visitClassType(ClassType t, Void ignored) {
3364 if (!t.isCompound()) {
3365 return super.visitClassType(t, ignored);
3366 } else {
3367 Type st = visit(supertype(t));
3368 List<Type> is = visit(interfaces(t), ignored);
3369 if (st == supertype(t) && is == interfaces(t))
3370 return t;
3371 else
3372 return makeIntersectionType(is.prepend(st));
3373 }
3374 }
3375
3376 @Override
3377 public Type visitWildcardType(WildcardType t, Void ignored) {
3378 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored);
3379 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) {
3380 t2.type = wildUpperBound(t2.type);
3381 }
3382 return t2;
3383 }
3384
3385 @Override
3386 public Type visitForAll(ForAll t, Void ignored) {
3387 if (Type.containsAny(to, t.tvars)) {
3388 //perform alpha-renaming of free-variables in 't'
3389 //if 'to' types contain variables that are free in 't'
3390 List<Type> freevars = newInstances(t.tvars);
3391 t = new ForAll(freevars,
3392 Types.this.subst(t.qtype, t.tvars, freevars));
3393 }
3394 List<Type> tvars1 = substBounds(t.tvars, from, to);
3395 Type qtype1 = visit(t.qtype);
3396 if (tvars1 == t.tvars && qtype1 == t.qtype) {
3397 return t;
3398 } else if (tvars1 == t.tvars) {
3399 return new ForAll(tvars1, qtype1) {
3400 @Override
3401 public boolean needsStripping() {
3402 return true;
3403 }
3404 };
3405 } else {
3406 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) {
3407 @Override
3408 public boolean needsStripping() {
3409 return true;
3410 }
3411 };
3412 }
3413 }
3414 }
3415
3416 public List<Type> substBounds(List<Type> tvars,
3417 List<Type> from,
3418 List<Type> to) {
3419 if (tvars.isEmpty())
3420 return tvars;
3421 ListBuffer<Type> newBoundsBuf = new ListBuffer<>();
3422 boolean changed = false;
3423 // calculate new bounds
3424 for (Type t : tvars) {
3425 TypeVar tv = (TypeVar) t;
3426 Type bound = subst(tv.getUpperBound(), from, to);
3427 if (bound != tv.getUpperBound())
3428 changed = true;
3429 newBoundsBuf.append(bound);
3430 }
3431 if (!changed)
3432 return tvars;
3433 ListBuffer<Type> newTvars = new ListBuffer<>();
3434 // create new type variables without bounds
3435 for (Type t : tvars) {
3436 newTvars.append(new TypeVar(t.tsym, null, syms.botType,
3437 t.getMetadata()));
3438 }
3439 // the new bounds should use the new type variables in place
3440 // of the old
3441 List<Type> newBounds = newBoundsBuf.toList();
3442 from = tvars;
3443 to = newTvars.toList();
3444 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
3445 newBounds.head = subst(newBounds.head, from, to);
3446 }
3447 newBounds = newBoundsBuf.toList();
3448 // set the bounds of new type variables to the new bounds
3449 for (Type t : newTvars.toList()) {
3450 TypeVar tv = (TypeVar) t;
3451 tv.setUpperBound( newBounds.head );
3452 newBounds = newBounds.tail;
3453 }
3454 return newTvars.toList();
3455 }
3456
3457 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
3458 Type bound1 = subst(t.getUpperBound(), from, to);
3459 if (bound1 == t.getUpperBound())
3460 return t;
3461 else {
3462 // create new type variable without bounds
3463 TypeVar tv = new TypeVar(t.tsym, null, syms.botType,
3464 t.getMetadata());
3465 // the new bound should use the new type variable in place
3466 // of the old
3467 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) );
3468 return tv;
3469 }
3470 }
3471 // </editor-fold>
3472
3473 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
3474 /**
3475 * Does t have the same bounds for quantified variables as s?
3476 */
3477 public boolean hasSameBounds(ForAll t, ForAll s) {
3478 List<Type> l1 = t.tvars;
3479 List<Type> l2 = s.tvars;
3480 while (l1.nonEmpty() && l2.nonEmpty() &&
3481 isSameType(l1.head.getUpperBound(),
3482 subst(l2.head.getUpperBound(),
3483 s.tvars,
3484 t.tvars))) {
3485 l1 = l1.tail;
3486 l2 = l2.tail;
3487 }
3488 return l1.isEmpty() && l2.isEmpty();
3489 }
3490 // </editor-fold>
3491
3492 // <editor-fold defaultstate="collapsed" desc="newInstances">
3493 /** Create new vector of type variables from list of variables
3494 * changing all recursive bounds from old to new list.
3495 */
3496 public List<Type> newInstances(List<Type> tvars) {
3497 List<Type> tvars1 = tvars.map(newInstanceFun);
3498 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
3499 TypeVar tv = (TypeVar) l.head;
3500 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) );
3501 }
3502 return tvars1;
3503 }
3504 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() {
3505 @Override
3506 public TypeVar visitTypeVar(TypeVar t, Void _unused) {
3507 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata());
3508 }
3509 };
3510 // </editor-fold>
3511
3512 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
3513 return original.accept(methodWithParameters, newParams);
3514 }
3515 // where
3516 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
3517 public Type visitType(Type t, List<Type> newParams) {
3518 throw new IllegalArgumentException("Not a method type: " + t);
3519 }
3520 public Type visitMethodType(MethodType t, List<Type> newParams) {
3521 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
3522 }
3523 public Type visitForAll(ForAll t, List<Type> newParams) {
3524 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
3525 }
3526 };
3527
3528 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
3529 return original.accept(methodWithThrown, newThrown);
3530 }
3531 // where
3532 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
3533 public Type visitType(Type t, List<Type> newThrown) {
3534 throw new IllegalArgumentException("Not a method type: " + t);
3535 }
3536 public Type visitMethodType(MethodType t, List<Type> newThrown) {
3537 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
3538 }
3539 public Type visitForAll(ForAll t, List<Type> newThrown) {
3540 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
3541 }
3542 };
3543
3544 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
3545 return original.accept(methodWithReturn, newReturn);
3546 }
3547 // where
3548 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
3549 public Type visitType(Type t, Type newReturn) {
3550 throw new IllegalArgumentException("Not a method type: " + t);
3551 }
3552 public Type visitMethodType(MethodType t, Type newReturn) {
3553 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) {
3554 @Override
3555 public Type baseType() {
3556 return t;
3557 }
3558 };
3559 }
3560 public Type visitForAll(ForAll t, Type newReturn) {
3561 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) {
3562 @Override
3563 public Type baseType() {
3564 return t;
3565 }
3566 };
3567 }
3568 };
3569
3570 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3571 public Type createErrorType(Type originalType) {
3572 return new ErrorType(originalType, syms.errSymbol);
3573 }
3574
3575 public Type createErrorType(ClassSymbol c, Type originalType) {
3576 return new ErrorType(c, originalType);
3577 }
3578
3579 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3580 return new ErrorType(name, container, originalType);
3581 }
3582 // </editor-fold>
3583
3584 // <editor-fold defaultstate="collapsed" desc="rank">
3585 /**
3586 * The rank of a class is the length of the longest path between
3587 * the class and java.lang.Object in the class inheritance
3588 * graph. Undefined for all but reference types.
3589 */
3590 public int rank(Type t) {
3591 switch(t.getTag()) {
3592 case CLASS: {
3593 ClassType cls = (ClassType)t;
3594 if (cls.rank_field < 0) {
3595 Name fullname = cls.tsym.getQualifiedName();
3596 if (fullname == names.java_lang_Object)
3597 cls.rank_field = 0;
3598 else {
3599 int r = rank(supertype(cls));
3600 for (List<Type> l = interfaces(cls);
3601 l.nonEmpty();
3602 l = l.tail) {
3603 if (rank(l.head) > r)
3604 r = rank(l.head);
3605 }
3606 cls.rank_field = r + 1;
3607 }
3608 }
3609 return cls.rank_field;
3610 }
3611 case TYPEVAR: {
3612 TypeVar tvar = (TypeVar)t;
3613 if (tvar.rank_field < 0) {
3614 int r = rank(supertype(tvar));
3615 for (List<Type> l = interfaces(tvar);
3616 l.nonEmpty();
3617 l = l.tail) {
3618 if (rank(l.head) > r) r = rank(l.head);
3619 }
3620 tvar.rank_field = r + 1;
3621 }
3622 return tvar.rank_field;
3623 }
3624 case ERROR:
3625 case NONE:
3626 return 0;
3627 default:
3628 throw new AssertionError();
3629 }
3630 }
3631 // </editor-fold>
3632
3633 /**
3634 * Helper method for generating a string representation of a given type
3635 * accordingly to a given locale
3636 */
3637 public String toString(Type t, Locale locale) {
3638 return Printer.createStandardPrinter(messages).visit(t, locale);
3639 }
3640
3641 /**
3642 * Helper method for generating a string representation of a given type
3643 * accordingly to a given locale
3644 */
3645 public String toString(Symbol t, Locale locale) {
3646 return Printer.createStandardPrinter(messages).visit(t, locale);
3647 }
3648
3649 // <editor-fold defaultstate="collapsed" desc="toString">
3650 /**
3651 * This toString is slightly more descriptive than the one on Type.
3652 *
3653 * @deprecated Types.toString(Type t, Locale l) provides better support
3654 * for localization
3655 */
3656 @Deprecated
3657 public String toString(Type t) {
3658 if (t.hasTag(FORALL)) {
3659 ForAll forAll = (ForAll)t;
3660 return typaramsString(forAll.tvars) + forAll.qtype;
3661 }
3662 return "" + t;
3663 }
3664 // where
3665 private String typaramsString(List<Type> tvars) {
3666 StringBuilder s = new StringBuilder();
3667 s.append('<');
3668 boolean first = true;
3669 for (Type t : tvars) {
3670 if (!first) s.append(", ");
3671 first = false;
3672 appendTyparamString(((TypeVar)t), s);
3673 }
3674 s.append('>');
3675 return s.toString();
3676 }
3677 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3678 buf.append(t);
3679 if (t.getUpperBound() == null ||
3680 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object)
3681 return;
3682 buf.append(" extends "); // Java syntax; no need for i18n
3683 Type bound = t.getUpperBound();
3684 if (!bound.isCompound()) {
3685 buf.append(bound);
3686 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3687 buf.append(supertype(t));
3688 for (Type intf : interfaces(t)) {
3689 buf.append('&');
3690 buf.append(intf);
3691 }
3692 } else {
3693 // No superclass was given in bounds.
3694 // In this case, supertype is Object, erasure is first interface.
3695 boolean first = true;
3696 for (Type intf : interfaces(t)) {
3697 if (!first) buf.append('&');
3698 first = false;
3699 buf.append(intf);
3700 }
3701 }
3702 }
3703 // </editor-fold>
3704
3705 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3706 /**
3707 * A cache for closures.
3708 *
3709 * <p>A closure is a list of all the supertypes and interfaces of
3710 * a class or interface type, ordered by ClassSymbol.precedes
3711 * (that is, subclasses come first, arbitrarily but fixed
3712 * otherwise).
3713 */
3714 private Map<Type,List<Type>> closureCache = new HashMap<>();
3715
3716 /**
3717 * Returns the closure of a class or interface type.
3718 */
3719 public List<Type> closure(Type t) {
3720 List<Type> cl = closureCache.get(t);
3721 if (cl == null) {
3722 Type st = supertype(t);
3723 if (!t.isCompound()) {
3724 if (st.hasTag(CLASS)) {
3725 cl = insert(closure(st), t);
3726 } else if (st.hasTag(TYPEVAR)) {
3727 cl = closure(st).prepend(t);
3728 } else {
3729 cl = List.of(t);
3730 }
3731 } else {
3732 cl = closure(supertype(t));
3733 }
3734 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3735 cl = union(cl, closure(l.head));
3736 closureCache.put(t, cl);
3737 }
3738 return cl;
3739 }
3740
3741 /**
3742 * Collect types into a new closure (using a {@code ClosureHolder})
3743 */
3744 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3745 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip),
3746 ClosureHolder::add,
3747 ClosureHolder::merge,
3748 ClosureHolder::closure);
3749 }
3750 //where
3751 class ClosureHolder {
3752 List<Type> closure;
3753 final boolean minClosure;
3754 final BiPredicate<Type, Type> shouldSkip;
3755
3756 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3757 this.closure = List.nil();
3758 this.minClosure = minClosure;
3759 this.shouldSkip = shouldSkip;
3760 }
3761
3762 void add(Type type) {
3763 closure = insert(closure, type, shouldSkip);
3764 }
3765
3766 ClosureHolder merge(ClosureHolder other) {
3767 closure = union(closure, other.closure, shouldSkip);
3768 return this;
3769 }
3770
3771 List<Type> closure() {
3772 return minClosure ? closureMin(closure) : closure;
3773 }
3774 }
3775
3776 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym;
3777
3778 /**
3779 * Insert a type in a closure
3780 */
3781 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) {
3782 if (cl.isEmpty()) {
3783 return cl.prepend(t);
3784 } else if (shouldSkip.test(t, cl.head)) {
3785 return cl;
3786 } else if (t.tsym.precedes(cl.head.tsym, this)) {
3787 return cl.prepend(t);
3788 } else {
3789 // t comes after head, or the two are unrelated
3790 return insert(cl.tail, t, shouldSkip).prepend(cl.head);
3791 }
3792 }
3793
3794 public List<Type> insert(List<Type> cl, Type t) {
3795 return insert(cl, t, basicClosureSkip);
3796 }
3797
3798 /**
3799 * Form the union of two closures
3800 */
3801 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) {
3802 if (cl1.isEmpty()) {
3803 return cl2;
3804 } else if (cl2.isEmpty()) {
3805 return cl1;
3806 } else if (shouldSkip.test(cl1.head, cl2.head)) {
3807 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
3808 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3809 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
3810 } else {
3811 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
3812 }
3813 }
3814
3815 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3816 return union(cl1, cl2, basicClosureSkip);
3817 }
3818
3819 /**
3820 * Intersect two closures
3821 */
3822 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3823 if (cl1 == cl2)
3824 return cl1;
3825 if (cl1.isEmpty() || cl2.isEmpty())
3826 return List.nil();
3827 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3828 return intersect(cl1.tail, cl2);
3829 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3830 return intersect(cl1, cl2.tail);
3831 if (isSameType(cl1.head, cl2.head))
3832 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3833 if (cl1.head.tsym == cl2.head.tsym &&
3834 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) {
3835 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3836 Type merge = merge(cl1.head,cl2.head);
3837 return intersect(cl1.tail, cl2.tail).prepend(merge);
3838 }
3839 if (cl1.head.isRaw() || cl2.head.isRaw())
3840 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3841 }
3842 return intersect(cl1.tail, cl2.tail);
3843 }
3844 // where
3845 class TypePair {
3846 final Type t1;
3847 final Type t2;;
3848
3849 TypePair(Type t1, Type t2) {
3850 this.t1 = t1;
3851 this.t2 = t2;
3852 }
3853 @Override
3854 public int hashCode() {
3855 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3856 }
3857 @Override
3858 public boolean equals(Object obj) {
3859 return (obj instanceof TypePair typePair)
3860 && isSameType(t1, typePair.t1)
3861 && isSameType(t2, typePair.t2);
3862 }
3863 }
3864 Set<TypePair> mergeCache = new HashSet<>();
3865 private Type merge(Type c1, Type c2) {
3866 ClassType class1 = (ClassType) c1;
3867 List<Type> act1 = class1.getTypeArguments();
3868 ClassType class2 = (ClassType) c2;
3869 List<Type> act2 = class2.getTypeArguments();
3870 ListBuffer<Type> merged = new ListBuffer<>();
3871 List<Type> typarams = class1.tsym.type.getTypeArguments();
3872
3873 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3874 if (containsType(act1.head, act2.head)) {
3875 merged.append(act1.head);
3876 } else if (containsType(act2.head, act1.head)) {
3877 merged.append(act2.head);
3878 } else {
3879 TypePair pair = new TypePair(c1, c2);
3880 Type m;
3881 if (mergeCache.add(pair)) {
3882 m = new WildcardType(lub(wildUpperBound(act1.head),
3883 wildUpperBound(act2.head)),
3884 BoundKind.EXTENDS,
3885 syms.boundClass);
3886 mergeCache.remove(pair);
3887 } else {
3888 m = new WildcardType(syms.objectType,
3889 BoundKind.UNBOUND,
3890 syms.boundClass);
3891 }
3892 merged.append(m.withTypeVar(typarams.head));
3893 }
3894 act1 = act1.tail;
3895 act2 = act2.tail;
3896 typarams = typarams.tail;
3897 }
3898 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3899 // There is no spec detailing how type annotations are to
3900 // be inherited. So set it to noAnnotations for now
3901 return new ClassType(class1.getEnclosingType(), merged.toList(),
3902 class1.tsym);
3903 }
3904
3905 /**
3906 * Return the minimum type of a closure, a compound type if no
3907 * unique minimum exists.
3908 */
3909 private Type compoundMin(List<Type> cl) {
3910 if (cl.isEmpty()) return syms.objectType;
3911 List<Type> compound = closureMin(cl);
3912 if (compound.isEmpty())
3913 return null;
3914 else if (compound.tail.isEmpty())
3915 return compound.head;
3916 else
3917 return makeIntersectionType(compound);
3918 }
3919
3920 /**
3921 * Return the minimum types of a closure, suitable for computing
3922 * compoundMin or glb.
3923 */
3924 private List<Type> closureMin(List<Type> cl) {
3925 ListBuffer<Type> classes = new ListBuffer<>();
3926 ListBuffer<Type> interfaces = new ListBuffer<>();
3927 Set<Type> toSkip = new HashSet<>();
3928 while (!cl.isEmpty()) {
3929 Type current = cl.head;
3930 boolean keep = !toSkip.contains(current);
3931 if (keep && current.hasTag(TYPEVAR)) {
3932 // skip lower-bounded variables with a subtype in cl.tail
3933 for (Type t : cl.tail) {
3934 if (isSubtypeNoCapture(t, current)) {
3935 keep = false;
3936 break;
3937 }
3938 }
3939 }
3940 if (keep) {
3941 if (current.isInterface())
3942 interfaces.append(current);
3943 else
3944 classes.append(current);
3945 for (Type t : cl.tail) {
3946 // skip supertypes of 'current' in cl.tail
3947 if (isSubtypeNoCapture(current, t))
3948 toSkip.add(t);
3949 }
3950 }
3951 cl = cl.tail;
3952 }
3953 return classes.appendList(interfaces).toList();
3954 }
3955
3956 /**
3957 * Return the least upper bound of list of types. if the lub does
3958 * not exist return null.
3959 */
3960 public Type lub(List<Type> ts) {
3961 return lub(ts.toArray(new Type[ts.length()]));
3962 }
3963
3964 /**
3965 * Return the least upper bound (lub) of set of types. If the lub
3966 * does not exist return the type of null (bottom).
3967 */
3968 public Type lub(Type... ts) {
3969 final int UNKNOWN_BOUND = 0;
3970 final int ARRAY_BOUND = 1;
3971 final int CLASS_BOUND = 2;
3972
3973 int[] kinds = new int[ts.length];
3974
3975 int boundkind = UNKNOWN_BOUND;
3976 for (int i = 0 ; i < ts.length ; i++) {
3977 Type t = ts[i];
3978 switch (t.getTag()) {
3979 case CLASS:
3980 boundkind |= kinds[i] = CLASS_BOUND;
3981 break;
3982 case ARRAY:
3983 boundkind |= kinds[i] = ARRAY_BOUND;
3984 break;
3985 case TYPEVAR:
3986 do {
3987 t = t.getUpperBound();
3988 } while (t.hasTag(TYPEVAR));
3989 if (t.hasTag(ARRAY)) {
3990 boundkind |= kinds[i] = ARRAY_BOUND;
3991 } else {
3992 boundkind |= kinds[i] = CLASS_BOUND;
3993 }
3994 break;
3995 default:
3996 kinds[i] = UNKNOWN_BOUND;
3997 if (t.isPrimitive())
3998 return syms.errType;
3999 }
4000 }
4001 switch (boundkind) {
4002 case 0:
4003 return syms.botType;
4004
4005 case ARRAY_BOUND:
4006 // calculate lub(A[], B[])
4007 Type[] elements = new Type[ts.length];
4008 for (int i = 0 ; i < ts.length ; i++) {
4009 Type elem = elements[i] = elemTypeFun.apply(ts[i]);
4010 if (elem.isPrimitive()) {
4011 // if a primitive type is found, then return
4012 // arraySuperType unless all the types are the
4013 // same
4014 Type first = ts[0];
4015 for (int j = 1 ; j < ts.length ; j++) {
4016 if (!isSameType(first, ts[j])) {
4017 // lub(int[], B[]) is Cloneable & Serializable
4018 return arraySuperType();
4019 }
4020 }
4021 // all the array types are the same, return one
4022 // lub(int[], int[]) is int[]
4023 return first;
4024 }
4025 }
4026 // lub(A[], B[]) is lub(A, B)[]
4027 return new ArrayType(lub(elements), syms.arrayClass);
4028
4029 case CLASS_BOUND:
4030 // calculate lub(A, B)
4031 int startIdx = 0;
4032 for (int i = 0; i < ts.length ; i++) {
4033 Type t = ts[i];
4034 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) {
4035 break;
4036 } else {
4037 startIdx++;
4038 }
4039 }
4040 Assert.check(startIdx < ts.length);
4041 //step 1 - compute erased candidate set (EC)
4042 List<Type> cl = erasedSupertypes(ts[startIdx]);
4043 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4044 Type t = ts[i];
4045 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
4046 cl = intersect(cl, erasedSupertypes(t));
4047 }
4048 //step 2 - compute minimal erased candidate set (MEC)
4049 List<Type> mec = closureMin(cl);
4050 //step 3 - for each element G in MEC, compute lci(Inv(G))
4051 List<Type> candidates = List.nil();
4052 for (Type erasedSupertype : mec) {
4053 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
4054 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4055 Type superType = asSuper(ts[i], erasedSupertype.tsym);
4056 lci = intersect(lci, superType != null ? List.of(superType) : List.nil());
4057 }
4058 candidates = candidates.appendList(lci);
4059 }
4060 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
4061 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
4062 return compoundMin(candidates);
4063
4064 default:
4065 // calculate lub(A, B[])
4066 List<Type> classes = List.of(arraySuperType());
4067 for (int i = 0 ; i < ts.length ; i++) {
4068 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays
4069 classes = classes.prepend(ts[i]);
4070 }
4071 // lub(A, B[]) is lub(A, arraySuperType)
4072 return lub(classes);
4073 }
4074 }
4075 // where
4076 List<Type> erasedSupertypes(Type t) {
4077 ListBuffer<Type> buf = new ListBuffer<>();
4078 for (Type sup : closure(t)) {
4079 if (sup.hasTag(TYPEVAR)) {
4080 buf.append(sup);
4081 } else {
4082 buf.append(erasure(sup));
4083 }
4084 }
4085 return buf.toList();
4086 }
4087
4088 private Type arraySuperType;
4089 private Type arraySuperType() {
4090 // initialized lazily to avoid problems during compiler startup
4091 if (arraySuperType == null) {
4092 // JLS 10.8: all arrays implement Cloneable and Serializable.
4093 arraySuperType = makeIntersectionType(List.of(syms.serializableType,
4094 syms.cloneableType), true);
4095 }
4096 return arraySuperType;
4097 }
4098 // </editor-fold>
4099
4100 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
4101 public Type glb(List<Type> ts) {
4102 Type t1 = ts.head;
4103 for (Type t2 : ts.tail) {
4104 if (t1.isErroneous())
4105 return t1;
4106 t1 = glb(t1, t2);
4107 }
4108 return t1;
4109 }
4110 //where
4111 public Type glb(Type t, Type s) {
4112 if (s == null)
4113 return t;
4114 else if (t.isPrimitive() || s.isPrimitive())
4115 return syms.errType;
4116 else if (isSubtypeNoCapture(t, s))
4117 return t;
4118 else if (isSubtypeNoCapture(s, t))
4119 return s;
4120
4121 List<Type> closure = union(closure(t), closure(s));
4122 return glbFlattened(closure, t);
4123 }
4124 //where
4125 /**
4126 * Perform glb for a list of non-primitive, non-error, non-compound types;
4127 * redundant elements are removed. Bounds should be ordered according to
4128 * {@link Symbol#precedes(TypeSymbol,Types)}.
4129 *
4130 * @param flatBounds List of type to glb
4131 * @param errT Original type to use if the result is an error type
4132 */
4133 private Type glbFlattened(List<Type> flatBounds, Type errT) {
4134 List<Type> bounds = closureMin(flatBounds);
4135
4136 if (bounds.isEmpty()) { // length == 0
4137 return syms.objectType;
4138 } else if (bounds.tail.isEmpty()) { // length == 1
4139 return bounds.head;
4140 } else { // length > 1
4141 int classCount = 0;
4142 List<Type> cvars = List.nil();
4143 List<Type> lowers = List.nil();
4144 for (Type bound : bounds) {
4145 if (!bound.isInterface()) {
4146 classCount++;
4147 Type lower = cvarLowerBound(bound);
4148 if (bound != lower && !lower.hasTag(BOT)) {
4149 cvars = cvars.append(bound);
4150 lowers = lowers.append(lower);
4151 }
4152 }
4153 }
4154 if (classCount > 1) {
4155 if (lowers.isEmpty()) {
4156 return createErrorType(errT);
4157 } else {
4158 // try again with lower bounds included instead of capture variables
4159 List<Type> newBounds = bounds.diff(cvars).appendList(lowers);
4160 return glb(newBounds);
4161 }
4162 }
4163 }
4164 return makeIntersectionType(bounds);
4165 }
4166 // </editor-fold>
4167
4168 // <editor-fold defaultstate="collapsed" desc="hashCode">
4169 /**
4170 * Compute a hash code on a type.
4171 */
4172 public int hashCode(Type t) {
4173 return hashCode(t, false);
4174 }
4175
4176 public int hashCode(Type t, boolean strict) {
4177 return strict ?
4178 hashCodeStrictVisitor.visit(t) :
4179 hashCodeVisitor.visit(t);
4180 }
4181 // where
4182 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor();
4183 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() {
4184 @Override
4185 public Integer visitTypeVar(TypeVar t, Void ignored) {
4186 return System.identityHashCode(t);
4187 }
4188 };
4189
4190 private static class HashCodeVisitor extends UnaryVisitor<Integer> {
4191 public Integer visitType(Type t, Void ignored) {
4192 return t.getTag().ordinal();
4193 }
4194
4195 @Override
4196 public Integer visitClassType(ClassType t, Void ignored) {
4197 int result = visit(t.getEnclosingType());
4198 result *= 127;
4199 result += t.tsym.flatName().hashCode();
4200 for (Type s : t.getTypeArguments()) {
4201 result *= 127;
4202 result += visit(s);
4203 }
4204 return result;
4205 }
4206
4207 @Override
4208 public Integer visitMethodType(MethodType t, Void ignored) {
4209 int h = METHOD.ordinal();
4210 for (List<Type> thisargs = t.argtypes;
4211 thisargs.tail != null;
4212 thisargs = thisargs.tail)
4213 h = (h << 5) + visit(thisargs.head);
4214 return (h << 5) + visit(t.restype);
4215 }
4216
4217 @Override
4218 public Integer visitWildcardType(WildcardType t, Void ignored) {
4219 int result = t.kind.hashCode();
4220 if (t.type != null) {
4221 result *= 127;
4222 result += visit(t.type);
4223 }
4224 return result;
4225 }
4226
4227 @Override
4228 public Integer visitArrayType(ArrayType t, Void ignored) {
4229 return visit(t.elemtype) + 12;
4230 }
4231
4232 @Override
4233 public Integer visitTypeVar(TypeVar t, Void ignored) {
4234 return System.identityHashCode(t);
4235 }
4236
4237 @Override
4238 public Integer visitUndetVar(UndetVar t, Void ignored) {
4239 return System.identityHashCode(t);
4240 }
4241
4242 @Override
4243 public Integer visitErrorType(ErrorType t, Void ignored) {
4244 return 0;
4245 }
4246 }
4247 // </editor-fold>
4248
4249 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
4250 /**
4251 * Does t have a result that is a subtype of the result type of s,
4252 * suitable for covariant returns? It is assumed that both types
4253 * are (possibly polymorphic) method types. Monomorphic method
4254 * types are handled in the obvious way. Polymorphic method types
4255 * require renaming all type variables of one to corresponding
4256 * type variables in the other, where correspondence is by
4257 * position in the type parameter list. */
4258 public boolean resultSubtype(Type t, Type s, Warner warner) {
4259 List<Type> tvars = t.getTypeArguments();
4260 List<Type> svars = s.getTypeArguments();
4261 Type tres = t.getReturnType();
4262 Type sres = subst(s.getReturnType(), svars, tvars);
4263 return covariantReturnType(tres, sres, warner);
4264 }
4265
4266 /**
4267 * Return-Type-Substitutable.
4268 * @jls 8.4.5 Method Result
4269 */
4270 public boolean returnTypeSubstitutable(Type r1, Type r2) {
4271 if (hasSameArgs(r1, r2))
4272 return resultSubtype(r1, r2, noWarnings);
4273 else
4274 return covariantReturnType(r1.getReturnType(),
4275 erasure(r2.getReturnType()),
4276 noWarnings);
4277 }
4278
4279 public boolean returnTypeSubstitutable(Type r1,
4280 Type r2, Type r2res,
4281 Warner warner) {
4282 if (isSameType(r1.getReturnType(), r2res))
4283 return true;
4284 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
4285 return false;
4286
4287 if (hasSameArgs(r1, r2))
4288 return covariantReturnType(r1.getReturnType(), r2res, warner);
4289 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
4290 return true;
4291 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
4292 return false;
4293 warner.warn(LintCategory.UNCHECKED);
4294 return true;
4295 }
4296
4297 /**
4298 * Is t an appropriate return type in an overrider for a
4299 * method that returns s?
4300 */
4301 public boolean covariantReturnType(Type t, Type s, Warner warner) {
4302 return
4303 isSameType(t, s) ||
4304 !t.isPrimitive() &&
4305 !s.isPrimitive() &&
4306 isAssignable(t, s, warner);
4307 }
4308 // </editor-fold>
4309
4310 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
4311 /**
4312 * Return the class that boxes the given primitive.
4313 */
4314 public ClassSymbol boxedClass(Type t) {
4315 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]);
4316 }
4317
4318 /**
4319 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
4320 */
4321 public Type boxedTypeOrType(Type t) {
4322 return t.isPrimitive() ?
4323 boxedClass(t).type :
4324 t;
4325 }
4326
4327 /**
4328 * Return the primitive type corresponding to a boxed type.
4329 */
4330 public Type unboxedType(Type t) {
4331 if (t.hasTag(ERROR))
4332 return Type.noType;
4333 for (int i=0; i<syms.boxedName.length; i++) {
4334 Name box = syms.boxedName[i];
4335 if (box != null &&
4336 asSuper(t, syms.enterClass(syms.java_base, box)) != null)
4337 return syms.typeOfTag[i];
4338 }
4339 return Type.noType;
4340 }
4341
4342 /**
4343 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
4344 */
4345 public Type unboxedTypeOrType(Type t) {
4346 Type unboxedType = unboxedType(t);
4347 return unboxedType.hasTag(NONE) ? t : unboxedType;
4348 }
4349 // </editor-fold>
4350
4351 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
4352 /*
4353 * JLS 5.1.10 Capture Conversion:
4354 *
4355 * Let G name a generic type declaration with n formal type
4356 * parameters A1 ... An with corresponding bounds U1 ... Un. There
4357 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
4358 * where, for 1 <= i <= n:
4359 *
4360 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
4361 * Si is a fresh type variable whose upper bound is
4362 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
4363 * type.
4364 *
4365 * + If Ti is a wildcard type argument of the form ? extends Bi,
4366 * then Si is a fresh type variable whose upper bound is
4367 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
4368 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
4369 * a compile-time error if for any two classes (not interfaces)
4370 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
4371 *
4372 * + If Ti is a wildcard type argument of the form ? super Bi,
4373 * then Si is a fresh type variable whose upper bound is
4374 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
4375 *
4376 * + Otherwise, Si = Ti.
4377 *
4378 * Capture conversion on any type other than a parameterized type
4379 * (4.5) acts as an identity conversion (5.1.1). Capture
4380 * conversions never require a special action at run time and
4381 * therefore never throw an exception at run time.
4382 *
4383 * Capture conversion is not applied recursively.
4384 */
4385 /**
4386 * Capture conversion as specified by the JLS.
4387 */
4388
4389 public List<Type> capture(List<Type> ts) {
4390 List<Type> buf = List.nil();
4391 for (Type t : ts) {
4392 buf = buf.prepend(capture(t));
4393 }
4394 return buf.reverse();
4395 }
4396
4397 public Type capture(Type t) {
4398 if (!t.hasTag(CLASS)) {
4399 return t;
4400 }
4401 if (t.getEnclosingType() != Type.noType) {
4402 Type capturedEncl = capture(t.getEnclosingType());
4403 if (capturedEncl != t.getEnclosingType()) {
4404 Type type1 = memberType(capturedEncl, t.tsym);
4405 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
4406 }
4407 }
4408 ClassType cls = (ClassType)t;
4409 if (cls.isRaw() || !cls.isParameterized())
4410 return cls;
4411
4412 ClassType G = (ClassType)cls.asElement().asType();
4413 List<Type> A = G.getTypeArguments();
4414 List<Type> T = cls.getTypeArguments();
4415 List<Type> S = freshTypeVariables(T);
4416
4417 List<Type> currentA = A;
4418 List<Type> currentT = T;
4419 List<Type> currentS = S;
4420 boolean captured = false;
4421 while (!currentA.isEmpty() &&
4422 !currentT.isEmpty() &&
4423 !currentS.isEmpty()) {
4424 if (currentS.head != currentT.head) {
4425 captured = true;
4426 WildcardType Ti = (WildcardType)currentT.head;
4427 Type Ui = currentA.head.getUpperBound();
4428 CapturedType Si = (CapturedType)currentS.head;
4429 if (Ui == null)
4430 Ui = syms.objectType;
4431 switch (Ti.kind) {
4432 case UNBOUND:
4433 Si.setUpperBound( subst(Ui, A, S) );
4434 Si.lower = syms.botType;
4435 break;
4436 case EXTENDS:
4437 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) );
4438 Si.lower = syms.botType;
4439 break;
4440 case SUPER:
4441 Si.setUpperBound( subst(Ui, A, S) );
4442 Si.lower = Ti.getSuperBound();
4443 break;
4444 }
4445 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound();
4446 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower;
4447 if (!Si.getUpperBound().hasTag(ERROR) &&
4448 !Si.lower.hasTag(ERROR) &&
4449 isSameType(tmpBound, tmpLower)) {
4450 currentS.head = Si.getUpperBound();
4451 }
4452 }
4453 currentA = currentA.tail;
4454 currentT = currentT.tail;
4455 currentS = currentS.tail;
4456 }
4457 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
4458 return erasure(t); // some "rare" type involved
4459
4460 if (captured)
4461 return new ClassType(cls.getEnclosingType(), S, cls.tsym,
4462 cls.getMetadata());
4463 else
4464 return t;
4465 }
4466 // where
4467 public List<Type> freshTypeVariables(List<Type> types) {
4468 ListBuffer<Type> result = new ListBuffer<>();
4469 for (Type t : types) {
4470 if (t.hasTag(WILDCARD)) {
4471 Type bound = ((WildcardType)t).getExtendsBound();
4472 if (bound == null)
4473 bound = syms.objectType;
4474 result.append(new CapturedType(capturedName,
4475 syms.noSymbol,
4476 bound,
4477 syms.botType,
4478 (WildcardType)t));
4479 } else {
4480 result.append(t);
4481 }
4482 }
4483 return result.toList();
4484 }
4485 // </editor-fold>
4486
4487 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
4488 private boolean sideCast(Type from, Type to, Warner warn) {
4489 // We are casting from type $from$ to type $to$, which are
4490 // non-final unrelated types. This method
4491 // tries to reject a cast by transferring type parameters
4492 // from $to$ to $from$ by common superinterfaces.
4493 boolean reverse = false;
4494 Type target = to;
4495 if ((to.tsym.flags() & INTERFACE) == 0) {
4496 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4497 reverse = true;
4498 to = from;
4499 from = target;
4500 }
4501 List<Type> commonSupers = superClosure(to, erasure(from));
4502 boolean giveWarning = commonSupers.isEmpty();
4503 // The arguments to the supers could be unified here to
4504 // get a more accurate analysis
4505 while (commonSupers.nonEmpty()) {
4506 Type t1 = asSuper(from, commonSupers.head.tsym);
4507 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
4508 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4509 return false;
4510 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
4511 commonSupers = commonSupers.tail;
4512 }
4513 if (giveWarning && !isReifiable(reverse ? from : to))
4514 warn.warn(LintCategory.UNCHECKED);
4515 return true;
4516 }
4517
4518 private boolean sideCastFinal(Type from, Type to, Warner warn) {
4519 // We are casting from type $from$ to type $to$, which are
4520 // unrelated types one of which is final and the other of
4521 // which is an interface. This method
4522 // tries to reject a cast by transferring type parameters
4523 // from the final class to the interface.
4524 boolean reverse = false;
4525 Type target = to;
4526 if ((to.tsym.flags() & INTERFACE) == 0) {
4527 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4528 reverse = true;
4529 to = from;
4530 from = target;
4531 }
4532 Assert.check((from.tsym.flags() & FINAL) != 0);
4533 Type t1 = asSuper(from, to.tsym);
4534 if (t1 == null) return false;
4535 Type t2 = to;
4536 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4537 return false;
4538 if (!isReifiable(target) &&
4539 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
4540 warn.warn(LintCategory.UNCHECKED);
4541 return true;
4542 }
4543
4544 private boolean giveWarning(Type from, Type to) {
4545 List<Type> bounds = to.isCompound() ?
4546 directSupertypes(to) : List.of(to);
4547 for (Type b : bounds) {
4548 Type subFrom = asSub(from, b.tsym);
4549 if (b.isParameterized() &&
4550 (!(isUnbounded(b) ||
4551 isSubtype(from, b) ||
4552 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
4553 return true;
4554 }
4555 }
4556 return false;
4557 }
4558
4559 private List<Type> superClosure(Type t, Type s) {
4560 List<Type> cl = List.nil();
4561 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
4562 if (isSubtype(s, erasure(l.head))) {
4563 cl = insert(cl, l.head);
4564 } else {
4565 cl = union(cl, superClosure(l.head, s));
4566 }
4567 }
4568 return cl;
4569 }
4570
4571 private boolean containsTypeEquivalent(Type t, Type s) {
4572 return isSameType(t, s) || // shortcut
4573 containsType(t, s) && containsType(s, t);
4574 }
4575
4576 // <editor-fold defaultstate="collapsed" desc="adapt">
4577 /**
4578 * Adapt a type by computing a substitution which maps a source
4579 * type to a target type.
4580 *
4581 * @param source the source type
4582 * @param target the target type
4583 * @param from the type variables of the computed substitution
4584 * @param to the types of the computed substitution.
4585 */
4586 public void adapt(Type source,
4587 Type target,
4588 ListBuffer<Type> from,
4589 ListBuffer<Type> to) throws AdaptFailure {
4590 new Adapter(from, to).adapt(source, target);
4591 }
4592
4593 class Adapter extends SimpleVisitor<Void, Type> {
4594
4595 ListBuffer<Type> from;
4596 ListBuffer<Type> to;
4597 Map<Symbol,Type> mapping;
4598
4599 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
4600 this.from = from;
4601 this.to = to;
4602 mapping = new HashMap<>();
4603 }
4604
4605 public void adapt(Type source, Type target) throws AdaptFailure {
4606 visit(source, target);
4607 List<Type> fromList = from.toList();
4608 List<Type> toList = to.toList();
4609 while (!fromList.isEmpty()) {
4610 Type val = mapping.get(fromList.head.tsym);
4611 if (toList.head != val)
4612 toList.head = val;
4613 fromList = fromList.tail;
4614 toList = toList.tail;
4615 }
4616 }
4617
4618 @Override
4619 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
4620 if (target.hasTag(CLASS))
4621 adaptRecursive(source.allparams(), target.allparams());
4622 return null;
4623 }
4624
4625 @Override
4626 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
4627 if (target.hasTag(ARRAY))
4628 adaptRecursive(elemtype(source), elemtype(target));
4629 return null;
4630 }
4631
4632 @Override
4633 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
4634 if (source.isExtendsBound())
4635 adaptRecursive(wildUpperBound(source), wildUpperBound(target));
4636 else if (source.isSuperBound())
4637 adaptRecursive(wildLowerBound(source), wildLowerBound(target));
4638 return null;
4639 }
4640
4641 @Override
4642 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
4643 // Check to see if there is
4644 // already a mapping for $source$, in which case
4645 // the old mapping will be merged with the new
4646 Type val = mapping.get(source.tsym);
4647 if (val != null) {
4648 if (val.isSuperBound() && target.isSuperBound()) {
4649 val = isSubtype(wildLowerBound(val), wildLowerBound(target))
4650 ? target : val;
4651 } else if (val.isExtendsBound() && target.isExtendsBound()) {
4652 val = isSubtype(wildUpperBound(val), wildUpperBound(target))
4653 ? val : target;
4654 } else if (!isSameType(val, target)) {
4655 throw new AdaptFailure();
4656 }
4657 } else {
4658 val = target;
4659 from.append(source);
4660 to.append(target);
4661 }
4662 mapping.put(source.tsym, val);
4663 return null;
4664 }
4665
4666 @Override
4667 public Void visitType(Type source, Type target) {
4668 return null;
4669 }
4670
4671 private Set<TypePair> cache = new HashSet<>();
4672
4673 private void adaptRecursive(Type source, Type target) {
4674 TypePair pair = new TypePair(source, target);
4675 if (cache.add(pair)) {
4676 try {
4677 visit(source, target);
4678 } finally {
4679 cache.remove(pair);
4680 }
4681 }
4682 }
4683
4684 private void adaptRecursive(List<Type> source, List<Type> target) {
4685 if (source.length() == target.length()) {
4686 while (source.nonEmpty()) {
4687 adaptRecursive(source.head, target.head);
4688 source = source.tail;
4689 target = target.tail;
4690 }
4691 }
4692 }
4693 }
4694
4695 public static class AdaptFailure extends RuntimeException {
4696 static final long serialVersionUID = -7490231548272701566L;
4697 }
4698
4699 private void adaptSelf(Type t,
4700 ListBuffer<Type> from,
4701 ListBuffer<Type> to) {
4702 try {
4703 //if (t.tsym.type != t)
4704 adapt(t.tsym.type, t, from, to);
4705 } catch (AdaptFailure ex) {
4706 // Adapt should never fail calculating a mapping from
4707 // t.tsym.type to t as there can be no merge problem.
4708 throw new AssertionError(ex);
4709 }
4710 }
4711 // </editor-fold>
4712
4713 /**
4714 * Rewrite all type variables (universal quantifiers) in the given
4715 * type to wildcards (existential quantifiers). This is used to
4716 * determine if a cast is allowed. For example, if high is true
4717 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4718 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4719 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4720 * List<Integer>} with a warning.
4721 * @param t a type
4722 * @param high if true return an upper bound; otherwise a lower
4723 * bound
4724 * @param rewriteTypeVars only rewrite captured wildcards if false;
4725 * otherwise rewrite all type variables
4726 * @return the type rewritten with wildcards (existential
4727 * quantifiers) only
4728 */
4729 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4730 return new Rewriter(high, rewriteTypeVars).visit(t);
4731 }
4732
4733 class Rewriter extends UnaryVisitor<Type> {
4734
4735 boolean high;
4736 boolean rewriteTypeVars;
4737
4738 Rewriter(boolean high, boolean rewriteTypeVars) {
4739 this.high = high;
4740 this.rewriteTypeVars = rewriteTypeVars;
4741 }
4742
4743 @Override
4744 public Type visitClassType(ClassType t, Void s) {
4745 ListBuffer<Type> rewritten = new ListBuffer<>();
4746 boolean changed = false;
4747 for (Type arg : t.allparams()) {
4748 Type bound = visit(arg);
4749 if (arg != bound) {
4750 changed = true;
4751 }
4752 rewritten.append(bound);
4753 }
4754 if (changed)
4755 return subst(t.tsym.type,
4756 t.tsym.type.allparams(),
4757 rewritten.toList());
4758 else
4759 return t;
4760 }
4761
4762 public Type visitType(Type t, Void s) {
4763 return t;
4764 }
4765
4766 @Override
4767 public Type visitCapturedType(CapturedType t, Void s) {
4768 Type w_bound = t.wildcard.type;
4769 Type bound = w_bound.contains(t) ?
4770 erasure(w_bound) :
4771 visit(w_bound);
4772 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4773 }
4774
4775 @Override
4776 public Type visitTypeVar(TypeVar t, Void s) {
4777 if (rewriteTypeVars) {
4778 Type bound = t.getUpperBound().contains(t) ?
4779 erasure(t.getUpperBound()) :
4780 visit(t.getUpperBound());
4781 return rewriteAsWildcardType(bound, t, EXTENDS);
4782 } else {
4783 return t;
4784 }
4785 }
4786
4787 @Override
4788 public Type visitWildcardType(WildcardType t, Void s) {
4789 Type bound2 = visit(t.type);
4790 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4791 }
4792
4793 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4794 switch (bk) {
4795 case EXTENDS: return high ?
4796 makeExtendsWildcard(B(bound), formal) :
4797 makeExtendsWildcard(syms.objectType, formal);
4798 case SUPER: return high ?
4799 makeSuperWildcard(syms.botType, formal) :
4800 makeSuperWildcard(B(bound), formal);
4801 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4802 default:
4803 Assert.error("Invalid bound kind " + bk);
4804 return null;
4805 }
4806 }
4807
4808 Type B(Type t) {
4809 while (t.hasTag(WILDCARD)) {
4810 WildcardType w = (WildcardType)t;
4811 t = high ?
4812 w.getExtendsBound() :
4813 w.getSuperBound();
4814 if (t == null) {
4815 t = high ? syms.objectType : syms.botType;
4816 }
4817 }
4818 return t;
4819 }
4820 }
4821
4822
4823 /**
4824 * Create a wildcard with the given upper (extends) bound; create
4825 * an unbounded wildcard if bound is Object.
4826 *
4827 * @param bound the upper bound
4828 * @param formal the formal type parameter that will be
4829 * substituted by the wildcard
4830 */
4831 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4832 if (bound == syms.objectType) {
4833 return new WildcardType(syms.objectType,
4834 BoundKind.UNBOUND,
4835 syms.boundClass,
4836 formal);
4837 } else {
4838 return new WildcardType(bound,
4839 BoundKind.EXTENDS,
4840 syms.boundClass,
4841 formal);
4842 }
4843 }
4844
4845 /**
4846 * Create a wildcard with the given lower (super) bound; create an
4847 * unbounded wildcard if bound is bottom (type of {@code null}).
4848 *
4849 * @param bound the lower bound
4850 * @param formal the formal type parameter that will be
4851 * substituted by the wildcard
4852 */
4853 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4854 if (bound.hasTag(BOT)) {
4855 return new WildcardType(syms.objectType,
4856 BoundKind.UNBOUND,
4857 syms.boundClass,
4858 formal);
4859 } else {
4860 return new WildcardType(bound,
4861 BoundKind.SUPER,
4862 syms.boundClass,
4863 formal);
4864 }
4865 }
4866
4867 /**
4868 * A wrapper for a type that allows use in sets.
4869 */
4870 public static class UniqueType {
4871 public final Type type;
4872 final Types types;
4873
4874 public UniqueType(Type type, Types types) {
4875 this.type = type;
4876 this.types = types;
4877 }
4878
4879 public int hashCode() {
4880 return types.hashCode(type);
4881 }
4882
4883 public boolean equals(Object obj) {
4884 return (obj instanceof UniqueType uniqueType) &&
4885 types.isSameType(type, uniqueType.type);
4886 }
4887
4888 public String toString() {
4889 return type.toString();
4890 }
4891
4892 }
4893 // </editor-fold>
4894
4895 // <editor-fold defaultstate="collapsed" desc="Visitors">
4896 /**
4897 * A default visitor for types. All visitor methods except
4898 * visitType are implemented by delegating to visitType. Concrete
4899 * subclasses must provide an implementation of visitType and can
4900 * override other methods as needed.
4901 *
4902 * @param <R> the return type of the operation implemented by this
4903 * visitor; use Void if no return type is needed.
4904 * @param <S> the type of the second argument (the first being the
4905 * type itself) of the operation implemented by this visitor; use
4906 * Void if a second argument is not needed.
4907 */
4908 public abstract static class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4909 public final R visit(Type t, S s) { return t.accept(this, s); }
4910 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4911 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4912 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4913 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4914 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4915 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); }
4916 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4917 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4918 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4919 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4920 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4921 }
4922
4923 /**
4924 * A default visitor for symbols. All visitor methods except
4925 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4926 * subclasses must provide an implementation of visitSymbol and can
4927 * override other methods as needed.
4928 *
4929 * @param <R> the return type of the operation implemented by this
4930 * visitor; use Void if no return type is needed.
4931 * @param <S> the type of the second argument (the first being the
4932 * symbol itself) of the operation implemented by this visitor; use
4933 * Void if a second argument is not needed.
4934 */
4935 public abstract static class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4936 public final R visit(Symbol s, S arg) { return s.accept(this, arg); }
4937 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4938 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4939 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4940 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4941 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4942 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4943 }
4944
4945 /**
4946 * A <em>simple</em> visitor for types. This visitor is simple as
4947 * captured wildcards, for-all types (generic methods), and
4948 * undetermined type variables (part of inference) are hidden.
4949 * Captured wildcards are hidden by treating them as type
4950 * variables and the rest are hidden by visiting their qtypes.
4951 *
4952 * @param <R> the return type of the operation implemented by this
4953 * visitor; use Void if no return type is needed.
4954 * @param <S> the type of the second argument (the first being the
4955 * type itself) of the operation implemented by this visitor; use
4956 * Void if a second argument is not needed.
4957 */
4958 public abstract static class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4959 @Override
4960 public R visitCapturedType(CapturedType t, S s) {
4961 return visitTypeVar(t, s);
4962 }
4963 @Override
4964 public R visitForAll(ForAll t, S s) {
4965 return visit(t.qtype, s);
4966 }
4967 @Override
4968 public R visitUndetVar(UndetVar t, S s) {
4969 return visit(t.qtype, s);
4970 }
4971 }
4972
4973 /**
4974 * A plain relation on types. That is a 2-ary function on the
4975 * form Type × Type → Boolean.
4976 * <!-- In plain text: Type x Type -> Boolean -->
4977 */
4978 public abstract static class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4979
4980 /**
4981 * A convenience visitor for implementing operations that only
4982 * require one argument (the type itself), that is, unary
4983 * operations.
4984 *
4985 * @param <R> the return type of the operation implemented by this
4986 * visitor; use Void if no return type is needed.
4987 */
4988 public abstract static class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4989 public final R visit(Type t) { return t.accept(this, null); }
4990 }
4991
4992 /**
4993 * A visitor for implementing a mapping from types to types. The
4994 * default behavior of this class is to implement the identity
4995 * mapping (mapping a type to itself). This can be overridden in
4996 * subclasses.
4997 *
4998 * @param <S> the type of the second argument (the first being the
4999 * type itself) of this mapping; use Void if a second argument is
5000 * not needed.
5001 */
5002 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
5003 public final Type visit(Type t) { return t.accept(this, null); }
5004 public Type visitType(Type t, S s) { return t; }
5005 }
5006
5007 /**
5008 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}.
5009 * This class implements the functional interface {@code Function}, that allows it to be used
5010 * fluently in stream-like processing.
5011 */
5012 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> {
5013 @Override
5014 public Type apply(Type type) { return visit(type); }
5015
5016 List<Type> visit(List<Type> ts, S s) {
5017 return ts.map(t -> visit(t, s));
5018 }
5019
5020 @Override
5021 public Type visitCapturedType(CapturedType t, S s) {
5022 return visitTypeVar(t, s);
5023 }
5024 }
5025 // </editor-fold>
5026
5027
5028 // <editor-fold defaultstate="collapsed" desc="Annotation support">
5029
5030 public RetentionPolicy getRetention(Attribute.Compound a) {
5031 return getRetention(a.type.tsym);
5032 }
5033
5034 public RetentionPolicy getRetention(TypeSymbol sym) {
5035 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
5036 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
5037 if (c != null) {
5038 Attribute value = c.member(names.value);
5039 if (value != null && value instanceof Attribute.Enum attributeEnum) {
5040 Name levelName = attributeEnum.value.name;
5041 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
5042 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
5043 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
5044 else ;// /* fail soft */ throw new AssertionError(levelName);
5045 }
5046 }
5047 return vis;
5048 }
5049 // </editor-fold>
5050
5051 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
5052
5053 public abstract static class SignatureGenerator {
5054
5055 public static class InvalidSignatureException extends RuntimeException {
5056 private static final long serialVersionUID = 0;
5057
5058 private final transient Type type;
5059
5060 InvalidSignatureException(Type type) {
5061 this.type = type;
5062 }
5063
5064 public Type type() {
5065 return type;
5066 }
5067
5068 @Override
5069 public Throwable fillInStackTrace() {
5070 // This is an internal exception; the stack trace is irrelevant.
5071 return this;
5072 }
5073 }
5074
5075 private final Types types;
5076
5077 protected abstract void append(char ch);
5078 protected abstract void append(byte[] ba);
5079 protected abstract void append(Name name);
5080 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
5081
5082 protected SignatureGenerator(Types types) {
5083 this.types = types;
5084 }
5085
5086 protected void reportIllegalSignature(Type t) {
5087 throw new InvalidSignatureException(t);
5088 }
5089
5090 /**
5091 * Assemble signature of given type in string buffer.
5092 */
5093 public void assembleSig(Type type) {
5094 switch (type.getTag()) {
5095 case BYTE:
5096 append('B');
5097 break;
5098 case SHORT:
5099 append('S');
5100 break;
5101 case CHAR:
5102 append('C');
5103 break;
5104 case INT:
5105 append('I');
5106 break;
5107 case LONG:
5108 append('J');
5109 break;
5110 case FLOAT:
5111 append('F');
5112 break;
5113 case DOUBLE:
5114 append('D');
5115 break;
5116 case BOOLEAN:
5117 append('Z');
5118 break;
5119 case VOID:
5120 append('V');
5121 break;
5122 case CLASS:
5123 if (type.isCompound()) {
5124 reportIllegalSignature(type);
5125 }
5126 append('L');
5127 assembleClassSig(type);
5128 append(';');
5129 break;
5130 case ARRAY:
5131 ArrayType at = (ArrayType) type;
5132 append('[');
5133 assembleSig(at.elemtype);
5134 break;
5135 case METHOD:
5136 MethodType mt = (MethodType) type;
5137 append('(');
5138 assembleSig(mt.argtypes);
5139 append(')');
5140 assembleSig(mt.restype);
5141 if (hasTypeVar(mt.thrown)) {
5142 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
5143 append('^');
5144 assembleSig(l.head);
5145 }
5146 }
5147 break;
5148 case WILDCARD: {
5149 Type.WildcardType ta = (Type.WildcardType) type;
5150 switch (ta.kind) {
5151 case SUPER:
5152 append('-');
5153 assembleSig(ta.type);
5154 break;
5155 case EXTENDS:
5156 append('+');
5157 assembleSig(ta.type);
5158 break;
5159 case UNBOUND:
5160 append('*');
5161 break;
5162 default:
5163 throw new AssertionError(ta.kind);
5164 }
5165 break;
5166 }
5167 case TYPEVAR:
5168 if (((TypeVar)type).isCaptured()) {
5169 reportIllegalSignature(type);
5170 }
5171 append('T');
5172 append(type.tsym.name);
5173 append(';');
5174 break;
5175 case FORALL:
5176 Type.ForAll ft = (Type.ForAll) type;
5177 assembleParamsSig(ft.tvars);
5178 assembleSig(ft.qtype);
5179 break;
5180 default:
5181 throw new AssertionError("typeSig " + type.getTag());
5182 }
5183 }
5184
5185 public boolean hasTypeVar(List<Type> l) {
5186 while (l.nonEmpty()) {
5187 if (l.head.hasTag(TypeTag.TYPEVAR)) {
5188 return true;
5189 }
5190 l = l.tail;
5191 }
5192 return false;
5193 }
5194
5195 public void assembleClassSig(Type type) {
5196 ClassType ct = (ClassType) type;
5197 ClassSymbol c = (ClassSymbol) ct.tsym;
5198 classReference(c);
5199 Type outer = ct.getEnclosingType();
5200 if (outer.allparams().nonEmpty()) {
5201 boolean rawOuter =
5202 c.owner.kind == MTH || // either a local class
5203 c.name == types.names.empty; // or anonymous
5204 assembleClassSig(rawOuter
5205 ? types.erasure(outer)
5206 : outer);
5207 append(rawOuter ? '$' : '.');
5208 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
5209 append(rawOuter
5210 ? c.flatname.subName(c.owner.enclClass().flatname.length() + 1)
5211 : c.name);
5212 } else {
5213 append(externalize(c.flatname));
5214 }
5215 if (ct.getTypeArguments().nonEmpty()) {
5216 append('<');
5217 assembleSig(ct.getTypeArguments());
5218 append('>');
5219 }
5220 }
5221
5222 public void assembleParamsSig(List<Type> typarams) {
5223 append('<');
5224 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
5225 Type.TypeVar tvar = (Type.TypeVar) ts.head;
5226 append(tvar.tsym.name);
5227 List<Type> bounds = types.getBounds(tvar);
5228 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
5229 append(':');
5230 }
5231 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
5232 append(':');
5233 assembleSig(l.head);
5234 }
5235 }
5236 append('>');
5237 }
5238
5239 public void assembleSig(List<Type> types) {
5240 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
5241 assembleSig(ts.head);
5242 }
5243 }
5244 }
5245
5246 public Type constantType(LoadableConstant c) {
5247 switch (c.poolTag()) {
5248 case ClassFile.CONSTANT_Class:
5249 return syms.classType;
5250 case ClassFile.CONSTANT_String:
5251 return syms.stringType;
5252 case ClassFile.CONSTANT_Integer:
5253 return syms.intType;
5254 case ClassFile.CONSTANT_Float:
5255 return syms.floatType;
5256 case ClassFile.CONSTANT_Long:
5257 return syms.longType;
5258 case ClassFile.CONSTANT_Double:
5259 return syms.doubleType;
5260 case ClassFile.CONSTANT_MethodHandle:
5261 return syms.methodHandleType;
5262 case ClassFile.CONSTANT_MethodType:
5263 return syms.methodTypeType;
5264 case ClassFile.CONSTANT_Dynamic:
5265 return ((DynamicVarSymbol)c).type;
5266 default:
5267 throw new AssertionError("Not a loadable constant: " + c.poolTag());
5268 }
5269 }
5270 // </editor-fold>
5271
5272 public void newRound() {
5273 descCache._map.clear();
5274 isDerivedRawCache.clear();
5275 implCache._map.clear();
5276 membersCache._map.clear();
5277 closureCache.clear();
5278 }
5279 }