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 !areDisjoint((ClassSymbol)t.tsym, (ClassSymbol)s.tsym);
1669 }
1670 return result;
1671 }
1672 // where
1673 private boolean areDisjoint(ClassSymbol ts, ClassSymbol ss) {
1674 if (isSubtype(erasure(ts.type), erasure(ss.type))) {
1675 return false;
1676 }
1677 // if both are classes or both are interfaces, shortcut
1678 if (ts.isInterface() == ss.isInterface() && isSubtype(erasure(ss.type), erasure(ts.type))) {
1679 return false;
1680 }
1681 if (ts.isInterface() && !ss.isInterface()) {
1682 /* so ts is interface but ss is a class
1683 * an interface is disjoint from a class if the class is disjoint form the interface
1684 */
1685 return areDisjoint(ss, ts);
1686 }
1687 // a final class that is not subtype of ss is disjoint
1688 if (!ts.isInterface() && ts.isFinal()) {
1689 return true;
1690 }
1691 // if at least one is sealed
1692 if (ts.isSealed() || ss.isSealed()) {
1693 // permitted subtypes have to be disjoint with the other symbol
1694 ClassSymbol sealedOne = ts.isSealed() ? ts : ss;
1695 ClassSymbol other = sealedOne == ts ? ss : ts;
1696 return sealedOne.permitted.stream().allMatch(sym -> areDisjoint((ClassSymbol)sym, other));
1697 }
1698 return false;
1699 }
1700
1701 private TypeRelation isCastable = new TypeRelation() {
1702
1703 public Boolean visitType(Type t, Type s) {
1704 if (s.hasTag(ERROR) || t.hasTag(NONE))
1705 return true;
1706
1707 switch (t.getTag()) {
1708 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1709 case DOUBLE:
1710 return s.isNumeric();
1711 case BOOLEAN:
1712 return s.hasTag(BOOLEAN);
1713 case VOID:
1714 return false;
1715 case BOT:
1716 return isSubtype(t, s);
1717 default:
1718 throw new AssertionError();
1719 }
1720 }
1721
1722 @Override
1723 public Boolean visitWildcardType(WildcardType t, Type s) {
1724 return isCastable(wildUpperBound(t), s, warnStack.head);
1725 }
1726
1727 @Override
1728 public Boolean visitClassType(ClassType t, Type s) {
1729 if (s.hasTag(ERROR) || s.hasTag(BOT))
1730 return true;
1731
1732 if (s.hasTag(TYPEVAR)) {
1733 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1734 warnStack.head.warn(LintCategory.UNCHECKED);
1735 return true;
1736 } else {
1737 return false;
1738 }
1739 }
1740
1741 if (t.isCompound() || s.isCompound()) {
1742 return !t.isCompound() ?
1743 visitCompoundType((ClassType)s, t, true) :
1744 visitCompoundType(t, s, false);
1745 }
1746
1747 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) {
1748 boolean upcast;
1749 if ((upcast = isSubtype(erasure(t), erasure(s)))
1750 || isSubtype(erasure(s), erasure(t))) {
1751 if (!upcast && s.hasTag(ARRAY)) {
1752 if (!isReifiable(s))
1753 warnStack.head.warn(LintCategory.UNCHECKED);
1754 return true;
1755 } else if (s.isRaw()) {
1756 return true;
1757 } else if (t.isRaw()) {
1758 if (!isUnbounded(s))
1759 warnStack.head.warn(LintCategory.UNCHECKED);
1760 return true;
1761 }
1762 // Assume |a| <: |b|
1763 final Type a = upcast ? t : s;
1764 final Type b = upcast ? s : t;
1765 final boolean HIGH = true;
1766 final boolean LOW = false;
1767 final boolean DONT_REWRITE_TYPEVARS = false;
1768 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1769 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1770 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1771 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1772 Type lowSub = asSub(bLow, aLow.tsym);
1773 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1774 if (highSub == null) {
1775 final boolean REWRITE_TYPEVARS = true;
1776 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1777 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1778 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1779 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1780 lowSub = asSub(bLow, aLow.tsym);
1781 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1782 }
1783 if (highSub != null) {
1784 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1785 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1786 }
1787 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1788 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1789 && !disjointTypes(aLow.allparams(), highSub.allparams())
1790 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1791 if (upcast ? giveWarning(a, b) :
1792 giveWarning(b, a))
1793 warnStack.head.warn(LintCategory.UNCHECKED);
1794 return true;
1795 }
1796 }
1797 if (isReifiable(s))
1798 return isSubtypeUnchecked(a, b);
1799 else
1800 return isSubtypeUnchecked(a, b, warnStack.head);
1801 }
1802
1803 // Sidecast
1804 if (s.hasTag(CLASS)) {
1805 if ((s.tsym.flags() & INTERFACE) != 0) {
1806 return ((t.tsym.flags() & FINAL) == 0)
1807 ? sideCast(t, s, warnStack.head)
1808 : sideCastFinal(t, s, warnStack.head);
1809 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1810 return ((s.tsym.flags() & FINAL) == 0)
1811 ? sideCast(t, s, warnStack.head)
1812 : sideCastFinal(t, s, warnStack.head);
1813 } else {
1814 // unrelated class types
1815 return false;
1816 }
1817 }
1818 }
1819 return false;
1820 }
1821
1822 boolean visitCompoundType(ClassType ct, Type s, boolean reverse) {
1823 Warner warn = noWarnings;
1824 for (Type c : directSupertypes(ct)) {
1825 warn.clear();
1826 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1827 return false;
1828 }
1829 if (warn.hasLint(LintCategory.UNCHECKED))
1830 warnStack.head.warn(LintCategory.UNCHECKED);
1831 return true;
1832 }
1833
1834 @Override
1835 public Boolean visitArrayType(ArrayType t, Type s) {
1836 switch (s.getTag()) {
1837 case ERROR:
1838 case BOT:
1839 return true;
1840 case TYPEVAR:
1841 if (isCastable(s, t, noWarnings)) {
1842 warnStack.head.warn(LintCategory.UNCHECKED);
1843 return true;
1844 } else {
1845 return false;
1846 }
1847 case CLASS:
1848 return isSubtype(t, s);
1849 case ARRAY:
1850 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1851 return elemtype(t).hasTag(elemtype(s).getTag());
1852 } else {
1853 return isCastable(elemtype(t), elemtype(s), warnStack.head);
1854 }
1855 default:
1856 return false;
1857 }
1858 }
1859
1860 @Override
1861 public Boolean visitTypeVar(TypeVar t, Type s) {
1862 switch (s.getTag()) {
1863 case ERROR:
1864 case BOT:
1865 return true;
1866 case TYPEVAR:
1867 if (isSubtype(t, s)) {
1868 return true;
1869 } else if (isCastable(t.getUpperBound(), s, noWarnings)) {
1870 warnStack.head.warn(LintCategory.UNCHECKED);
1871 return true;
1872 } else {
1873 return false;
1874 }
1875 default:
1876 return isCastable(t.getUpperBound(), s, warnStack.head);
1877 }
1878 }
1879
1880 @Override
1881 public Boolean visitErrorType(ErrorType t, Type s) {
1882 return true;
1883 }
1884 };
1885 // </editor-fold>
1886
1887 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1888 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1889 while (ts.tail != null && ss.tail != null) {
1890 if (disjointType(ts.head, ss.head)) return true;
1891 ts = ts.tail;
1892 ss = ss.tail;
1893 }
1894 return false;
1895 }
1896
1897 /**
1898 * Two types or wildcards are considered disjoint if it can be
1899 * proven that no type can be contained in both. It is
1900 * conservative in that it is allowed to say that two types are
1901 * not disjoint, even though they actually are.
1902 *
1903 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1904 * {@code X} and {@code Y} are not disjoint.
1905 */
1906 public boolean disjointType(Type t, Type s) {
1907 return disjointType.visit(t, s);
1908 }
1909 // where
1910 private TypeRelation disjointType = new TypeRelation() {
1911
1912 private Set<TypePair> cache = new HashSet<>();
1913
1914 @Override
1915 public Boolean visitType(Type t, Type s) {
1916 if (s.hasTag(WILDCARD))
1917 return visit(s, t);
1918 else
1919 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1920 }
1921
1922 private boolean isCastableRecursive(Type t, Type s) {
1923 TypePair pair = new TypePair(t, s);
1924 if (cache.add(pair)) {
1925 try {
1926 return Types.this.isCastable(t, s);
1927 } finally {
1928 cache.remove(pair);
1929 }
1930 } else {
1931 return true;
1932 }
1933 }
1934
1935 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1936 TypePair pair = new TypePair(t, s);
1937 if (cache.add(pair)) {
1938 try {
1939 return Types.this.notSoftSubtype(t, s);
1940 } finally {
1941 cache.remove(pair);
1942 }
1943 } else {
1944 return false;
1945 }
1946 }
1947
1948 @Override
1949 public Boolean visitWildcardType(WildcardType t, Type s) {
1950 if (t.isUnbound())
1951 return false;
1952
1953 if (!s.hasTag(WILDCARD)) {
1954 if (t.isExtendsBound())
1955 return notSoftSubtypeRecursive(s, t.type);
1956 else
1957 return notSoftSubtypeRecursive(t.type, s);
1958 }
1959
1960 if (s.isUnbound())
1961 return false;
1962
1963 if (t.isExtendsBound()) {
1964 if (s.isExtendsBound())
1965 return !isCastableRecursive(t.type, wildUpperBound(s));
1966 else if (s.isSuperBound())
1967 return notSoftSubtypeRecursive(wildLowerBound(s), t.type);
1968 } else if (t.isSuperBound()) {
1969 if (s.isExtendsBound())
1970 return notSoftSubtypeRecursive(t.type, wildUpperBound(s));
1971 }
1972 return false;
1973 }
1974 };
1975 // </editor-fold>
1976
1977 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds">
1978 public List<Type> cvarLowerBounds(List<Type> ts) {
1979 return ts.map(cvarLowerBoundMapping);
1980 }
1981 private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() {
1982 @Override
1983 public Type visitCapturedType(CapturedType t, Void _unused) {
1984 return cvarLowerBound(t);
1985 }
1986 };
1987 // </editor-fold>
1988
1989 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1990 /**
1991 * This relation answers the question: is impossible that
1992 * something of type `t' can be a subtype of `s'? This is
1993 * different from the question "is `t' not a subtype of `s'?"
1994 * when type variables are involved: Integer is not a subtype of T
1995 * where {@code <T extends Number>} but it is not true that Integer cannot
1996 * possibly be a subtype of T.
1997 */
1998 public boolean notSoftSubtype(Type t, Type s) {
1999 if (t == s) return false;
2000 if (t.hasTag(TYPEVAR)) {
2001 TypeVar tv = (TypeVar) t;
2002 return !isCastable(tv.getUpperBound(),
2003 relaxBound(s),
2004 noWarnings);
2005 }
2006 if (!s.hasTag(WILDCARD))
2007 s = cvarUpperBound(s);
2008
2009 return !isSubtype(t, relaxBound(s));
2010 }
2011
2012 private Type relaxBound(Type t) {
2013 return (t.hasTag(TYPEVAR)) ?
2014 rewriteQuantifiers(skipTypeVars(t, false), true, true) :
2015 t;
2016 }
2017 // </editor-fold>
2018
2019 // <editor-fold defaultstate="collapsed" desc="isReifiable">
2020 public boolean isReifiable(Type t) {
2021 return isReifiable.visit(t);
2022 }
2023 // where
2024 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
2025
2026 public Boolean visitType(Type t, Void ignored) {
2027 return true;
2028 }
2029
2030 @Override
2031 public Boolean visitClassType(ClassType t, Void ignored) {
2032 if (t.isCompound())
2033 return false;
2034 else {
2035 if (!t.isParameterized())
2036 return true;
2037
2038 for (Type param : t.allparams()) {
2039 if (!param.isUnbound())
2040 return false;
2041 }
2042 return true;
2043 }
2044 }
2045
2046 @Override
2047 public Boolean visitArrayType(ArrayType t, Void ignored) {
2048 return visit(t.elemtype);
2049 }
2050
2051 @Override
2052 public Boolean visitTypeVar(TypeVar t, Void ignored) {
2053 return false;
2054 }
2055 };
2056 // </editor-fold>
2057
2058 // <editor-fold defaultstate="collapsed" desc="Array Utils">
2059 public boolean isArray(Type t) {
2060 while (t.hasTag(WILDCARD))
2061 t = wildUpperBound(t);
2062 return t.hasTag(ARRAY);
2063 }
2064
2065 /**
2066 * The element type of an array.
2067 */
2068 public Type elemtype(Type t) {
2069 switch (t.getTag()) {
2070 case WILDCARD:
2071 return elemtype(wildUpperBound(t));
2072 case ARRAY:
2073 return ((ArrayType)t).elemtype;
2074 case FORALL:
2075 return elemtype(((ForAll)t).qtype);
2076 case ERROR:
2077 return t;
2078 default:
2079 return null;
2080 }
2081 }
2082
2083 public Type elemtypeOrType(Type t) {
2084 Type elemtype = elemtype(t);
2085 return elemtype != null ?
2086 elemtype :
2087 t;
2088 }
2089
2090 /**
2091 * Mapping to take element type of an arraytype
2092 */
2093 private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() {
2094 @Override
2095 public Type visitArrayType(ArrayType t, Void _unused) {
2096 return t.elemtype;
2097 }
2098
2099 @Override
2100 public Type visitTypeVar(TypeVar t, Void _unused) {
2101 return visit(skipTypeVars(t, false));
2102 }
2103 };
2104
2105 /**
2106 * The number of dimensions of an array type.
2107 */
2108 public int dimensions(Type t) {
2109 int result = 0;
2110 while (t.hasTag(ARRAY)) {
2111 result++;
2112 t = elemtype(t);
2113 }
2114 return result;
2115 }
2116
2117 /**
2118 * Returns an ArrayType with the component type t
2119 *
2120 * @param t The component type of the ArrayType
2121 * @return the ArrayType for the given component
2122 */
2123 public ArrayType makeArrayType(Type t) {
2124 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) {
2125 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
2126 }
2127 return new ArrayType(t, syms.arrayClass);
2128 }
2129 // </editor-fold>
2130
2131 // <editor-fold defaultstate="collapsed" desc="asSuper">
2132 /**
2133 * Return the (most specific) base type of t that starts with the
2134 * given symbol. If none exists, return null.
2135 *
2136 * Caveat Emptor: Since javac represents the class of all arrays with a singleton
2137 * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant,
2138 * this method could yield surprising answers when invoked on arrays. For example when
2139 * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null.
2140 *
2141 * @param t a type
2142 * @param sym a symbol
2143 */
2144 public Type asSuper(Type t, Symbol sym) {
2145 /* Some examples:
2146 *
2147 * (Enum<E>, Comparable) => Comparable<E>
2148 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind>
2149 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree
2150 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) =>
2151 * Iterable<capture#160 of ? extends c.s.s.d.DocTree>
2152 */
2153 if (sym.type == syms.objectType) { //optimization
2154 return syms.objectType;
2155 }
2156 return asSuper.visit(t, sym);
2157 }
2158 // where
2159 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
2160
2161 private Set<Symbol> seenTypes = new HashSet<>();
2162
2163 public Type visitType(Type t, Symbol sym) {
2164 return null;
2165 }
2166
2167 @Override
2168 public Type visitClassType(ClassType t, Symbol sym) {
2169 if (t.tsym == sym)
2170 return t;
2171
2172 Symbol c = t.tsym;
2173 if (!seenTypes.add(c)) {
2174 return null;
2175 }
2176 try {
2177 Type st = supertype(t);
2178 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) {
2179 Type x = asSuper(st, sym);
2180 if (x != null)
2181 return x;
2182 }
2183 if ((sym.flags() & INTERFACE) != 0) {
2184 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
2185 if (!l.head.hasTag(ERROR)) {
2186 Type x = asSuper(l.head, sym);
2187 if (x != null)
2188 return x;
2189 }
2190 }
2191 }
2192 return null;
2193 } finally {
2194 seenTypes.remove(c);
2195 }
2196 }
2197
2198 @Override
2199 public Type visitArrayType(ArrayType t, Symbol sym) {
2200 return isSubtype(t, sym.type) ? sym.type : null;
2201 }
2202
2203 @Override
2204 public Type visitTypeVar(TypeVar t, Symbol sym) {
2205 if (t.tsym == sym)
2206 return t;
2207 else
2208 return asSuper(t.getUpperBound(), sym);
2209 }
2210
2211 @Override
2212 public Type visitErrorType(ErrorType t, Symbol sym) {
2213 return t;
2214 }
2215 };
2216
2217 /**
2218 * Return the base type of t or any of its outer types that starts
2219 * with the given symbol. If none exists, return null.
2220 *
2221 * @param t a type
2222 * @param sym a symbol
2223 */
2224 public Type asOuterSuper(Type t, Symbol sym) {
2225 switch (t.getTag()) {
2226 case CLASS:
2227 do {
2228 Type s = asSuper(t, sym);
2229 if (s != null) return s;
2230 t = t.getEnclosingType();
2231 } while (t.hasTag(CLASS));
2232 return null;
2233 case ARRAY:
2234 return isSubtype(t, sym.type) ? sym.type : null;
2235 case TYPEVAR:
2236 return asSuper(t, sym);
2237 case ERROR:
2238 return t;
2239 default:
2240 return null;
2241 }
2242 }
2243
2244 /**
2245 * Return the base type of t or any of its enclosing types that
2246 * starts with the given symbol. If none exists, return null.
2247 *
2248 * @param t a type
2249 * @param sym a symbol
2250 */
2251 public Type asEnclosingSuper(Type t, Symbol sym) {
2252 switch (t.getTag()) {
2253 case CLASS:
2254 do {
2255 Type s = asSuper(t, sym);
2256 if (s != null) return s;
2257 Type outer = t.getEnclosingType();
2258 t = (outer.hasTag(CLASS)) ? outer :
2259 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
2260 Type.noType;
2261 } while (t.hasTag(CLASS));
2262 return null;
2263 case ARRAY:
2264 return isSubtype(t, sym.type) ? sym.type : null;
2265 case TYPEVAR:
2266 return asSuper(t, sym);
2267 case ERROR:
2268 return t;
2269 default:
2270 return null;
2271 }
2272 }
2273 // </editor-fold>
2274
2275 // <editor-fold defaultstate="collapsed" desc="memberType">
2276 /**
2277 * The type of given symbol, seen as a member of t.
2278 *
2279 * @param t a type
2280 * @param sym a symbol
2281 */
2282 public Type memberType(Type t, Symbol sym) {
2283 return (sym.flags() & STATIC) != 0
2284 ? sym.type
2285 : memberType.visit(t, sym);
2286 }
2287 // where
2288 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
2289
2290 public Type visitType(Type t, Symbol sym) {
2291 return sym.type;
2292 }
2293
2294 @Override
2295 public Type visitWildcardType(WildcardType t, Symbol sym) {
2296 return memberType(wildUpperBound(t), sym);
2297 }
2298
2299 @Override
2300 public Type visitClassType(ClassType t, Symbol sym) {
2301 Symbol owner = sym.owner;
2302 long flags = sym.flags();
2303 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
2304 Type base = asOuterSuper(t, owner);
2305 //if t is an intersection type T = CT & I1 & I2 ... & In
2306 //its supertypes CT, I1, ... In might contain wildcards
2307 //so we need to go through capture conversion
2308 base = t.isCompound() ? capture(base) : base;
2309 if (base != null) {
2310 List<Type> ownerParams = owner.type.allparams();
2311 List<Type> baseParams = base.allparams();
2312 if (ownerParams.nonEmpty()) {
2313 if (baseParams.isEmpty()) {
2314 // then base is a raw type
2315 return erasure(sym.type);
2316 } else {
2317 return subst(sym.type, ownerParams, baseParams);
2318 }
2319 }
2320 }
2321 }
2322 return sym.type;
2323 }
2324
2325 @Override
2326 public Type visitTypeVar(TypeVar t, Symbol sym) {
2327 return memberType(t.getUpperBound(), sym);
2328 }
2329
2330 @Override
2331 public Type visitErrorType(ErrorType t, Symbol sym) {
2332 return t;
2333 }
2334 };
2335 // </editor-fold>
2336
2337 // <editor-fold defaultstate="collapsed" desc="isAssignable">
2338 public boolean isAssignable(Type t, Type s) {
2339 return isAssignable(t, s, noWarnings);
2340 }
2341
2342 /**
2343 * Is t assignable to s?<br>
2344 * Equivalent to subtype except for constant values and raw
2345 * types.<br>
2346 * (not defined for Method and ForAll types)
2347 */
2348 public boolean isAssignable(Type t, Type s, Warner warn) {
2349 if (t.hasTag(ERROR))
2350 return true;
2351 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) {
2352 int value = ((Number)t.constValue()).intValue();
2353 switch (s.getTag()) {
2354 case BYTE:
2355 case CHAR:
2356 case SHORT:
2357 case INT:
2358 if (s.getTag().checkRange(value))
2359 return true;
2360 break;
2361 case CLASS:
2362 switch (unboxedType(s).getTag()) {
2363 case BYTE:
2364 case CHAR:
2365 case SHORT:
2366 return isAssignable(t, unboxedType(s), warn);
2367 }
2368 break;
2369 }
2370 }
2371 return isConvertible(t, s, warn);
2372 }
2373 // </editor-fold>
2374
2375 // <editor-fold defaultstate="collapsed" desc="erasure">
2376 /**
2377 * The erasure of t {@code |t|} -- the type that results when all
2378 * type parameters in t are deleted.
2379 */
2380 public Type erasure(Type t) {
2381 return eraseNotNeeded(t) ? t : erasure(t, false);
2382 }
2383 //where
2384 private boolean eraseNotNeeded(Type t) {
2385 // We don't want to erase primitive types and String type as that
2386 // operation is idempotent. Also, erasing these could result in loss
2387 // of information such as constant values attached to such types.
2388 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2389 }
2390
2391 private Type erasure(Type t, boolean recurse) {
2392 if (t.isPrimitive()) {
2393 return t; /* fast special case */
2394 } else {
2395 Type out = erasure.visit(t, recurse);
2396 return out;
2397 }
2398 }
2399 // where
2400 private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() {
2401 private Type combineMetadata(final Type s,
2402 final Type t) {
2403 if (t.getMetadata().nonEmpty()) {
2404 switch (s.getKind()) {
2405 case OTHER:
2406 case UNION:
2407 case INTERSECTION:
2408 case PACKAGE:
2409 case EXECUTABLE:
2410 case NONE:
2411 case VOID:
2412 case ERROR:
2413 return s;
2414 default: return s.dropMetadata(Annotations.class);
2415 }
2416 } else {
2417 return s;
2418 }
2419 }
2420
2421 public Type visitType(Type t, Boolean recurse) {
2422 if (t.isPrimitive())
2423 return t; /*fast special case*/
2424 else {
2425 //other cases already handled
2426 return combineMetadata(t, t);
2427 }
2428 }
2429
2430 @Override
2431 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2432 Type erased = erasure(wildUpperBound(t), recurse);
2433 return combineMetadata(erased, t);
2434 }
2435
2436 @Override
2437 public Type visitClassType(ClassType t, Boolean recurse) {
2438 Type erased = t.tsym.erasure(Types.this);
2439 if (recurse) {
2440 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym,
2441 t.dropMetadata(Annotations.class).getMetadata());
2442 return erased;
2443 } else {
2444 return combineMetadata(erased, t);
2445 }
2446 }
2447
2448 @Override
2449 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2450 Type erased = erasure(t.getUpperBound(), recurse);
2451 return combineMetadata(erased, t);
2452 }
2453 };
2454
2455 public List<Type> erasure(List<Type> ts) {
2456 return erasure.visit(ts, false);
2457 }
2458
2459 public Type erasureRecursive(Type t) {
2460 return erasure(t, true);
2461 }
2462
2463 public List<Type> erasureRecursive(List<Type> ts) {
2464 return erasure.visit(ts, true);
2465 }
2466 // </editor-fold>
2467
2468 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType">
2469 /**
2470 * Make an intersection type from non-empty list of types. The list should be ordered according to
2471 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion.
2472 * Hence, this version of makeIntersectionType may not be called during a classfile read.
2473 *
2474 * @param bounds the types from which the intersection type is formed
2475 */
2476 public IntersectionClassType makeIntersectionType(List<Type> bounds) {
2477 return makeIntersectionType(bounds, bounds.head.tsym.isInterface());
2478 }
2479
2480 /**
2481 * Make an intersection type from non-empty list of types. The list should be ordered according to
2482 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as
2483 * an extra parameter indicates as to whether all bounds are interfaces - in which case the
2484 * supertype is implicitly assumed to be 'Object'.
2485 *
2486 * @param bounds the types from which the intersection type is formed
2487 * @param allInterfaces are all bounds interface types?
2488 */
2489 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) {
2490 Assert.check(bounds.nonEmpty());
2491 Type firstExplicitBound = bounds.head;
2492 if (allInterfaces) {
2493 bounds = bounds.prepend(syms.objectType);
2494 }
2495 ClassSymbol bc =
2496 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2497 Type.moreInfo
2498 ? names.fromString(bounds.toString())
2499 : names.empty,
2500 null,
2501 syms.noSymbol);
2502 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces);
2503 bc.type = intersectionType;
2504 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
2505 syms.objectType : // error condition, recover
2506 erasure(firstExplicitBound);
2507 bc.members_field = WriteableScope.create(bc);
2508 return intersectionType;
2509 }
2510 // </editor-fold>
2511
2512 // <editor-fold defaultstate="collapsed" desc="supertype">
2513 public Type supertype(Type t) {
2514 return supertype.visit(t);
2515 }
2516 // where
2517 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2518
2519 public Type visitType(Type t, Void ignored) {
2520 // A note on wildcards: there is no good way to
2521 // determine a supertype for a lower-bounded wildcard.
2522 return Type.noType;
2523 }
2524
2525 @Override
2526 public Type visitClassType(ClassType t, Void ignored) {
2527 if (t.supertype_field == null) {
2528 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2529 // An interface has no superclass; its supertype is Object.
2530 if (t.isInterface())
2531 supertype = ((ClassType)t.tsym.type).supertype_field;
2532 if (t.supertype_field == null) {
2533 List<Type> actuals = classBound(t).allparams();
2534 List<Type> formals = t.tsym.type.allparams();
2535 if (t.hasErasedSupertypes()) {
2536 t.supertype_field = erasureRecursive(supertype);
2537 } else if (formals.nonEmpty()) {
2538 t.supertype_field = subst(supertype, formals, actuals);
2539 }
2540 else {
2541 t.supertype_field = supertype;
2542 }
2543 }
2544 }
2545 return t.supertype_field;
2546 }
2547
2548 /**
2549 * The supertype is always a class type. If the type
2550 * variable's bounds start with a class type, this is also
2551 * the supertype. Otherwise, the supertype is
2552 * java.lang.Object.
2553 */
2554 @Override
2555 public Type visitTypeVar(TypeVar t, Void ignored) {
2556 if (t.getUpperBound().hasTag(TYPEVAR) ||
2557 (!t.getUpperBound().isCompound() && !t.getUpperBound().isInterface())) {
2558 return t.getUpperBound();
2559 } else {
2560 return supertype(t.getUpperBound());
2561 }
2562 }
2563
2564 @Override
2565 public Type visitArrayType(ArrayType t, Void ignored) {
2566 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2567 return arraySuperType();
2568 else
2569 return new ArrayType(supertype(t.elemtype), t.tsym);
2570 }
2571
2572 @Override
2573 public Type visitErrorType(ErrorType t, Void ignored) {
2574 return Type.noType;
2575 }
2576 };
2577 // </editor-fold>
2578
2579 // <editor-fold defaultstate="collapsed" desc="interfaces">
2580 /**
2581 * Return the interfaces implemented by this class.
2582 */
2583 public List<Type> interfaces(Type t) {
2584 return interfaces.visit(t);
2585 }
2586 // where
2587 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2588
2589 public List<Type> visitType(Type t, Void ignored) {
2590 return List.nil();
2591 }
2592
2593 @Override
2594 public List<Type> visitClassType(ClassType t, Void ignored) {
2595 if (t.interfaces_field == null) {
2596 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2597 if (t.interfaces_field == null) {
2598 // If t.interfaces_field is null, then t must
2599 // be a parameterized type (not to be confused
2600 // with a generic type declaration).
2601 // Terminology:
2602 // Parameterized type: List<String>
2603 // Generic type declaration: class List<E> { ... }
2604 // So t corresponds to List<String> and
2605 // t.tsym.type corresponds to List<E>.
2606 // The reason t must be parameterized type is
2607 // that completion will happen as a side
2608 // effect of calling
2609 // ClassSymbol.getInterfaces. Since
2610 // t.interfaces_field is null after
2611 // completion, we can assume that t is not the
2612 // type of a class/interface declaration.
2613 Assert.check(t != t.tsym.type, t);
2614 List<Type> actuals = t.allparams();
2615 List<Type> formals = t.tsym.type.allparams();
2616 if (t.hasErasedSupertypes()) {
2617 t.interfaces_field = erasureRecursive(interfaces);
2618 } else if (formals.nonEmpty()) {
2619 t.interfaces_field = subst(interfaces, formals, actuals);
2620 }
2621 else {
2622 t.interfaces_field = interfaces;
2623 }
2624 }
2625 }
2626 return t.interfaces_field;
2627 }
2628
2629 @Override
2630 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2631 if (t.getUpperBound().isCompound())
2632 return interfaces(t.getUpperBound());
2633
2634 if (t.getUpperBound().isInterface())
2635 return List.of(t.getUpperBound());
2636
2637 return List.nil();
2638 }
2639 };
2640
2641 public List<Type> directSupertypes(Type t) {
2642 return directSupertypes.visit(t);
2643 }
2644 // where
2645 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() {
2646
2647 public List<Type> visitType(final Type type, final Void ignored) {
2648 if (!type.isIntersection()) {
2649 final Type sup = supertype(type);
2650 return (sup == Type.noType || sup == type || sup == null)
2651 ? interfaces(type)
2652 : interfaces(type).prepend(sup);
2653 } else {
2654 return ((IntersectionClassType)type).getExplicitComponents();
2655 }
2656 }
2657 };
2658
2659 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2660 for (Type i2 : interfaces(origin.type)) {
2661 if (isym == i2.tsym) return true;
2662 }
2663 return false;
2664 }
2665 // </editor-fold>
2666
2667 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2668 Map<Type,Boolean> isDerivedRawCache = new HashMap<>();
2669
2670 public boolean isDerivedRaw(Type t) {
2671 Boolean result = isDerivedRawCache.get(t);
2672 if (result == null) {
2673 result = isDerivedRawInternal(t);
2674 isDerivedRawCache.put(t, result);
2675 }
2676 return result;
2677 }
2678
2679 public boolean isDerivedRawInternal(Type t) {
2680 if (t.isErroneous())
2681 return false;
2682 return
2683 t.isRaw() ||
2684 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) ||
2685 isDerivedRaw(interfaces(t));
2686 }
2687
2688 public boolean isDerivedRaw(List<Type> ts) {
2689 List<Type> l = ts;
2690 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2691 return l.nonEmpty();
2692 }
2693 // </editor-fold>
2694
2695 // <editor-fold defaultstate="collapsed" desc="setBounds">
2696 /**
2697 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly,
2698 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise
2699 * the supertype is simply left null (in this case, the supertype is assumed to be the head of
2700 * the bound list passed as second argument). Note that this check might cause a symbol completion.
2701 * Hence, this version of setBounds may not be called during a classfile read.
2702 *
2703 * @param t a type variable
2704 * @param bounds the bounds, must be nonempty
2705 */
2706 public void setBounds(TypeVar t, List<Type> bounds) {
2707 setBounds(t, bounds, bounds.head.tsym.isInterface());
2708 }
2709
2710 /**
2711 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds.
2712 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds
2713 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'.
2714 *
2715 * @param t a type variable
2716 * @param bounds the bounds, must be nonempty
2717 * @param allInterfaces are all bounds interface types?
2718 */
2719 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2720 t.setUpperBound( bounds.tail.isEmpty() ?
2721 bounds.head :
2722 makeIntersectionType(bounds, allInterfaces) );
2723 t.rank_field = -1;
2724 }
2725 // </editor-fold>
2726
2727 // <editor-fold defaultstate="collapsed" desc="getBounds">
2728 /**
2729 * Return list of bounds of the given type variable.
2730 */
2731 public List<Type> getBounds(TypeVar t) {
2732 if (t.getUpperBound().hasTag(NONE))
2733 return List.nil();
2734 else if (t.getUpperBound().isErroneous() || !t.getUpperBound().isCompound())
2735 return List.of(t.getUpperBound());
2736 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2737 return interfaces(t).prepend(supertype(t));
2738 else
2739 // No superclass was given in bounds.
2740 // In this case, supertype is Object, erasure is first interface.
2741 return interfaces(t);
2742 }
2743 // </editor-fold>
2744
2745 // <editor-fold defaultstate="collapsed" desc="classBound">
2746 /**
2747 * If the given type is a (possibly selected) type variable,
2748 * return the bounding class of this type, otherwise return the
2749 * type itself.
2750 */
2751 public Type classBound(Type t) {
2752 return classBound.visit(t);
2753 }
2754 // where
2755 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2756
2757 public Type visitType(Type t, Void ignored) {
2758 return t;
2759 }
2760
2761 @Override
2762 public Type visitClassType(ClassType t, Void ignored) {
2763 Type outer1 = classBound(t.getEnclosingType());
2764 if (outer1 != t.getEnclosingType())
2765 return new ClassType(outer1, t.getTypeArguments(), t.tsym,
2766 t.getMetadata());
2767 else
2768 return t;
2769 }
2770
2771 @Override
2772 public Type visitTypeVar(TypeVar t, Void ignored) {
2773 return classBound(supertype(t));
2774 }
2775
2776 @Override
2777 public Type visitErrorType(ErrorType t, Void ignored) {
2778 return t;
2779 }
2780 };
2781 // </editor-fold>
2782
2783 // <editor-fold defaultstate="collapsed" desc="subsignature / override equivalence">
2784 /**
2785 * Returns true iff the first signature is a <em>subsignature</em>
2786 * of the other. This is <b>not</b> an equivalence
2787 * relation.
2788 *
2789 * @jls 8.4.2 Method Signature
2790 * @see #overrideEquivalent(Type t, Type s)
2791 * @param t first signature (possibly raw).
2792 * @param s second signature (could be subjected to erasure).
2793 * @return true if t is a subsignature of s.
2794 */
2795 public boolean isSubSignature(Type t, Type s) {
2796 return hasSameArgs(t, s, true) || hasSameArgs(t, erasure(s), true);
2797 }
2798
2799 /**
2800 * Returns true iff these signatures are related by <em>override
2801 * equivalence</em>. This is the natural extension of
2802 * isSubSignature to an equivalence relation.
2803 *
2804 * @jls 8.4.2 Method Signature
2805 * @see #isSubSignature(Type t, Type s)
2806 * @param t a signature (possible raw, could be subjected to
2807 * erasure).
2808 * @param s a signature (possible raw, could be subjected to
2809 * erasure).
2810 * @return true if either argument is a subsignature of the other.
2811 */
2812 public boolean overrideEquivalent(Type t, Type s) {
2813 return hasSameArgs(t, s) ||
2814 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2815 }
2816
2817 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2818 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) {
2819 if (msym.overrides(sym, origin, Types.this, true)) {
2820 return true;
2821 }
2822 }
2823 return false;
2824 }
2825
2826 /**
2827 * This enum defines the strategy for implementing most specific return type check
2828 * during the most specific and functional interface checks.
2829 */
2830 public enum MostSpecificReturnCheck {
2831 /**
2832 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling
2833 * method type variables (if either method is generic) and (ii) subtyping should be replaced
2834 * by type-equivalence for primitives. This is essentially an inlined version of
2835 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been
2836 * replaced with a strict subtyping check.
2837 */
2838 BASIC() {
2839 @Override
2840 public boolean test(Type mt1, Type mt2, Types types) {
2841 List<Type> tvars = mt1.getTypeArguments();
2842 List<Type> svars = mt2.getTypeArguments();
2843 Type t = mt1.getReturnType();
2844 Type s = types.subst(mt2.getReturnType(), svars, tvars);
2845 return types.isSameType(t, s) ||
2846 !t.isPrimitive() &&
2847 !s.isPrimitive() &&
2848 types.isSubtype(t, s);
2849 }
2850 },
2851 /**
2852 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2.
2853 */
2854 RTS() {
2855 @Override
2856 public boolean test(Type mt1, Type mt2, Types types) {
2857 return types.returnTypeSubstitutable(mt1, mt2);
2858 }
2859 };
2860
2861 public abstract boolean test(Type mt1, Type mt2, Types types);
2862 }
2863
2864 /**
2865 * Merge multiple abstract methods. The preferred method is a method that is a subsignature
2866 * of all the other signatures and whose return type is more specific {@link MostSpecificReturnCheck}.
2867 * The resulting preferred method has a throws clause that is the intersection of the merged
2868 * methods' clauses.
2869 */
2870 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) {
2871 //first check for preconditions
2872 boolean shouldErase = false;
2873 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes();
2874 for (Symbol s : ambiguousInOrder) {
2875 if ((s.flags() & ABSTRACT) == 0 ||
2876 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) {
2877 return Optional.empty();
2878 } else if (s.type.hasTag(FORALL)) {
2879 shouldErase = true;
2880 }
2881 }
2882 //then merge abstracts
2883 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) {
2884 outer: for (Symbol s : ambiguousInOrder) {
2885 Type mt = memberType(site, s);
2886 List<Type> allThrown = mt.getThrownTypes();
2887 for (Symbol s2 : ambiguousInOrder) {
2888 if (s != s2) {
2889 Type mt2 = memberType(site, s2);
2890 if (!isSubSignature(mt, mt2) ||
2891 !mostSpecificReturnCheck.test(mt, mt2, this)) {
2892 //ambiguity cannot be resolved
2893 continue outer;
2894 } else {
2895 List<Type> thrownTypes2 = mt2.getThrownTypes();
2896 if (!mt.hasTag(FORALL) && shouldErase) {
2897 thrownTypes2 = erasure(thrownTypes2);
2898 } else if (mt.hasTag(FORALL)) {
2899 //subsignature implies that if most specific is generic, then all other
2900 //methods are too
2901 Assert.check(mt2.hasTag(FORALL));
2902 // if both are generic methods, adjust thrown types ahead of intersection computation
2903 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments());
2904 }
2905 allThrown = chk.intersect(allThrown, thrownTypes2);
2906 }
2907 }
2908 }
2909 return (allThrown == mt.getThrownTypes()) ?
2910 Optional.of(s) :
2911 Optional.of(new MethodSymbol(
2912 s.flags(),
2913 s.name,
2914 createMethodTypeWithThrown(s.type, allThrown),
2915 s.owner) {
2916 @Override
2917 public Symbol baseSymbol() {
2918 return s;
2919 }
2920 });
2921 }
2922 }
2923 return Optional.empty();
2924 }
2925
2926 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2927 class ImplementationCache {
2928
2929 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>();
2930
2931 class Entry {
2932 final MethodSymbol cachedImpl;
2933 final Predicate<Symbol> implFilter;
2934 final boolean checkResult;
2935 final int prevMark;
2936
2937 public Entry(MethodSymbol cachedImpl,
2938 Predicate<Symbol> scopeFilter,
2939 boolean checkResult,
2940 int prevMark) {
2941 this.cachedImpl = cachedImpl;
2942 this.implFilter = scopeFilter;
2943 this.checkResult = checkResult;
2944 this.prevMark = prevMark;
2945 }
2946
2947 boolean matches(Predicate<Symbol> scopeFilter, boolean checkResult, int mark) {
2948 return this.implFilter == scopeFilter &&
2949 this.checkResult == checkResult &&
2950 this.prevMark == mark;
2951 }
2952 }
2953
2954 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2955 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2956 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2957 if (cache == null) {
2958 cache = new HashMap<>();
2959 _map.put(ms, new SoftReference<>(cache));
2960 }
2961 Entry e = cache.get(origin);
2962 CompoundScope members = membersClosure(origin.type, true);
2963 if (e == null ||
2964 !e.matches(implFilter, checkResult, members.getMark())) {
2965 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2966 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2967 return impl;
2968 }
2969 else {
2970 return e.cachedImpl;
2971 }
2972 }
2973
2974 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2975 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
2976 t = skipTypeVars(t, false);
2977 TypeSymbol c = t.tsym;
2978 Symbol bestSoFar = null;
2979 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) {
2980 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) {
2981 bestSoFar = sym;
2982 if ((sym.flags() & ABSTRACT) == 0) {
2983 //if concrete impl is found, exit immediately
2984 break;
2985 }
2986 }
2987 }
2988 if (bestSoFar != null) {
2989 //return either the (only) concrete implementation or the first abstract one
2990 return (MethodSymbol)bestSoFar;
2991 }
2992 }
2993 return null;
2994 }
2995 }
2996
2997 private ImplementationCache implCache = new ImplementationCache();
2998
2999 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
3000 return implCache.get(ms, origin, checkResult, implFilter);
3001 }
3002 // </editor-fold>
3003
3004 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
3005 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> {
3006
3007 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>();
3008
3009 Set<TypeSymbol> seenTypes = new HashSet<>();
3010
3011 class MembersScope extends CompoundScope {
3012
3013 CompoundScope scope;
3014
3015 public MembersScope(CompoundScope scope) {
3016 super(scope.owner);
3017 this.scope = scope;
3018 }
3019
3020 Predicate<Symbol> combine(Predicate<Symbol> sf) {
3021 return s -> !s.owner.isInterface() && (sf == null || sf.test(s));
3022 }
3023
3024 @Override
3025 public Iterable<Symbol> getSymbols(Predicate<Symbol> sf, LookupKind lookupKind) {
3026 return scope.getSymbols(combine(sf), lookupKind);
3027 }
3028
3029 @Override
3030 public Iterable<Symbol> getSymbolsByName(Name name, Predicate<Symbol> sf, LookupKind lookupKind) {
3031 return scope.getSymbolsByName(name, combine(sf), lookupKind);
3032 }
3033
3034 @Override
3035 public int getMark() {
3036 return scope.getMark();
3037 }
3038 }
3039
3040 CompoundScope nilScope;
3041
3042 /** members closure visitor methods **/
3043
3044 public CompoundScope visitType(Type t, Void _unused) {
3045 if (nilScope == null) {
3046 nilScope = new CompoundScope(syms.noSymbol);
3047 }
3048 return nilScope;
3049 }
3050
3051 @Override
3052 public CompoundScope visitClassType(ClassType t, Void _unused) {
3053 if (!seenTypes.add(t.tsym)) {
3054 //this is possible when an interface is implemented in multiple
3055 //superclasses, or when a class hierarchy is circular - in such
3056 //cases we don't need to recurse (empty scope is returned)
3057 return new CompoundScope(t.tsym);
3058 }
3059 try {
3060 seenTypes.add(t.tsym);
3061 ClassSymbol csym = (ClassSymbol)t.tsym;
3062 CompoundScope membersClosure = _map.get(csym);
3063 if (membersClosure == null) {
3064 membersClosure = new CompoundScope(csym);
3065 for (Type i : interfaces(t)) {
3066 membersClosure.prependSubScope(visit(i, null));
3067 }
3068 membersClosure.prependSubScope(visit(supertype(t), null));
3069 membersClosure.prependSubScope(csym.members());
3070 _map.put(csym, membersClosure);
3071 }
3072 return membersClosure;
3073 }
3074 finally {
3075 seenTypes.remove(t.tsym);
3076 }
3077 }
3078
3079 @Override
3080 public CompoundScope visitTypeVar(TypeVar t, Void _unused) {
3081 return visit(t.getUpperBound(), null);
3082 }
3083 }
3084
3085 private MembersClosureCache membersCache = new MembersClosureCache();
3086
3087 public CompoundScope membersClosure(Type site, boolean skipInterface) {
3088 CompoundScope cs = membersCache.visit(site, null);
3089 Assert.checkNonNull(cs, () -> "type " + site);
3090 return skipInterface ? membersCache.new MembersScope(cs) : cs;
3091 }
3092 // </editor-fold>
3093
3094
3095 /** Return first abstract member of class `sym'.
3096 */
3097 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) {
3098 try {
3099 return firstUnimplementedAbstractImpl(sym, sym);
3100 } catch (CompletionFailure ex) {
3101 chk.completionError(enter.getEnv(sym).tree.pos(), ex);
3102 return null;
3103 }
3104 }
3105 //where:
3106 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) {
3107 MethodSymbol undef = null;
3108 // Do not bother to search in classes that are not abstract,
3109 // since they cannot have abstract members.
3110 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
3111 Scope s = c.members();
3112 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
3113 if (sym.kind == MTH &&
3114 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
3115 MethodSymbol absmeth = (MethodSymbol)sym;
3116 MethodSymbol implmeth = absmeth.implementation(impl, this, true);
3117 if (implmeth == null || implmeth == absmeth) {
3118 //look for default implementations
3119 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head;
3120 if (prov != null && prov.overrides(absmeth, impl, this, true)) {
3121 implmeth = prov;
3122 }
3123 }
3124 if (implmeth == null || implmeth == absmeth) {
3125 undef = absmeth;
3126 break;
3127 }
3128 }
3129 }
3130 if (undef == null) {
3131 Type st = supertype(c.type);
3132 if (st.hasTag(CLASS))
3133 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym);
3134 }
3135 for (List<Type> l = interfaces(c.type);
3136 undef == null && l.nonEmpty();
3137 l = l.tail) {
3138 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym);
3139 }
3140 }
3141 return undef;
3142 }
3143
3144 public class CandidatesCache {
3145 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>();
3146
3147 class Entry {
3148 Type site;
3149 MethodSymbol msym;
3150
3151 Entry(Type site, MethodSymbol msym) {
3152 this.site = site;
3153 this.msym = msym;
3154 }
3155
3156 @Override
3157 public boolean equals(Object obj) {
3158 return (obj instanceof Entry entry)
3159 && entry.msym == msym
3160 && isSameType(site, entry.site);
3161 }
3162
3163 @Override
3164 public int hashCode() {
3165 return Types.this.hashCode(site) & ~msym.hashCode();
3166 }
3167 }
3168
3169 public List<MethodSymbol> get(Entry e) {
3170 return cache.get(e);
3171 }
3172
3173 public void put(Entry e, List<MethodSymbol> msymbols) {
3174 cache.put(e, msymbols);
3175 }
3176 }
3177
3178 public CandidatesCache candidatesCache = new CandidatesCache();
3179
3180 //where
3181 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
3182 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms);
3183 List<MethodSymbol> candidates = candidatesCache.get(e);
3184 if (candidates == null) {
3185 Predicate<Symbol> filter = new MethodFilter(ms, site);
3186 List<MethodSymbol> candidates2 = List.nil();
3187 for (Symbol s : membersClosure(site, false).getSymbols(filter)) {
3188 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
3189 return List.of((MethodSymbol)s);
3190 } else if (!candidates2.contains(s)) {
3191 candidates2 = candidates2.prepend((MethodSymbol)s);
3192 }
3193 }
3194 candidates = prune(candidates2);
3195 candidatesCache.put(e, candidates);
3196 }
3197 return candidates;
3198 }
3199
3200 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
3201 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>();
3202 for (MethodSymbol m1 : methods) {
3203 boolean isMin_m1 = true;
3204 for (MethodSymbol m2 : methods) {
3205 if (m1 == m2) continue;
3206 if (m2.owner != m1.owner &&
3207 asSuper(m2.owner.type, m1.owner) != null) {
3208 isMin_m1 = false;
3209 break;
3210 }
3211 }
3212 if (isMin_m1)
3213 methodsMin.append(m1);
3214 }
3215 return methodsMin.toList();
3216 }
3217 // where
3218 private class MethodFilter implements Predicate<Symbol> {
3219
3220 Symbol msym;
3221 Type site;
3222
3223 MethodFilter(Symbol msym, Type site) {
3224 this.msym = msym;
3225 this.site = site;
3226 }
3227
3228 @Override
3229 public boolean test(Symbol s) {
3230 return s.kind == MTH &&
3231 s.name == msym.name &&
3232 (s.flags() & SYNTHETIC) == 0 &&
3233 s.isInheritedIn(site.tsym, Types.this) &&
3234 overrideEquivalent(memberType(site, s), memberType(site, msym));
3235 }
3236 }
3237 // </editor-fold>
3238
3239 /**
3240 * Does t have the same arguments as s? It is assumed that both
3241 * types are (possibly polymorphic) method types. Monomorphic
3242 * method types "have the same arguments", if their argument lists
3243 * are equal. Polymorphic method types "have the same arguments",
3244 * if they have the same arguments after renaming all type
3245 * variables of one to corresponding type variables in the other,
3246 * where correspondence is by position in the type parameter list.
3247 */
3248 public boolean hasSameArgs(Type t, Type s) {
3249 return hasSameArgs(t, s, true);
3250 }
3251
3252 public boolean hasSameArgs(Type t, Type s, boolean strict) {
3253 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
3254 }
3255
3256 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
3257 return hasSameArgs.visit(t, s);
3258 }
3259 // where
3260 private class HasSameArgs extends TypeRelation {
3261
3262 boolean strict;
3263
3264 public HasSameArgs(boolean strict) {
3265 this.strict = strict;
3266 }
3267
3268 public Boolean visitType(Type t, Type s) {
3269 throw new AssertionError();
3270 }
3271
3272 @Override
3273 public Boolean visitMethodType(MethodType t, Type s) {
3274 return s.hasTag(METHOD)
3275 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
3276 }
3277
3278 @Override
3279 public Boolean visitForAll(ForAll t, Type s) {
3280 if (!s.hasTag(FORALL))
3281 return strict ? false : visitMethodType(t.asMethodType(), s);
3282
3283 ForAll forAll = (ForAll)s;
3284 return hasSameBounds(t, forAll)
3285 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
3286 }
3287
3288 @Override
3289 public Boolean visitErrorType(ErrorType t, Type s) {
3290 return false;
3291 }
3292 }
3293
3294 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
3295 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
3296
3297 // </editor-fold>
3298
3299 // <editor-fold defaultstate="collapsed" desc="subst">
3300 public List<Type> subst(List<Type> ts,
3301 List<Type> from,
3302 List<Type> to) {
3303 return ts.map(new Subst(from, to));
3304 }
3305
3306 /**
3307 * Substitute all occurrences of a type in `from' with the
3308 * corresponding type in `to' in 't'. Match lists `from' and `to'
3309 * from the right: If lists have different length, discard leading
3310 * elements of the longer list.
3311 */
3312 public Type subst(Type t, List<Type> from, List<Type> to) {
3313 return t.map(new Subst(from, to));
3314 }
3315
3316 private class Subst extends StructuralTypeMapping<Void> {
3317 List<Type> from;
3318 List<Type> to;
3319
3320 public Subst(List<Type> from, List<Type> to) {
3321 int fromLength = from.length();
3322 int toLength = to.length();
3323 while (fromLength > toLength) {
3324 fromLength--;
3325 from = from.tail;
3326 }
3327 while (fromLength < toLength) {
3328 toLength--;
3329 to = to.tail;
3330 }
3331 this.from = from;
3332 this.to = to;
3333 }
3334
3335 @Override
3336 public Type visitTypeVar(TypeVar t, Void ignored) {
3337 for (List<Type> from = this.from, to = this.to;
3338 from.nonEmpty();
3339 from = from.tail, to = to.tail) {
3340 if (t.equalsIgnoreMetadata(from.head)) {
3341 return to.head.withTypeVar(t);
3342 }
3343 }
3344 return t;
3345 }
3346
3347 @Override
3348 public Type visitClassType(ClassType t, Void ignored) {
3349 if (!t.isCompound()) {
3350 return super.visitClassType(t, ignored);
3351 } else {
3352 Type st = visit(supertype(t));
3353 List<Type> is = visit(interfaces(t), ignored);
3354 if (st == supertype(t) && is == interfaces(t))
3355 return t;
3356 else
3357 return makeIntersectionType(is.prepend(st));
3358 }
3359 }
3360
3361 @Override
3362 public Type visitWildcardType(WildcardType t, Void ignored) {
3363 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored);
3364 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) {
3365 t2.type = wildUpperBound(t2.type);
3366 }
3367 return t2;
3368 }
3369
3370 @Override
3371 public Type visitForAll(ForAll t, Void ignored) {
3372 if (Type.containsAny(to, t.tvars)) {
3373 //perform alpha-renaming of free-variables in 't'
3374 //if 'to' types contain variables that are free in 't'
3375 List<Type> freevars = newInstances(t.tvars);
3376 t = new ForAll(freevars,
3377 Types.this.subst(t.qtype, t.tvars, freevars));
3378 }
3379 List<Type> tvars1 = substBounds(t.tvars, from, to);
3380 Type qtype1 = visit(t.qtype);
3381 if (tvars1 == t.tvars && qtype1 == t.qtype) {
3382 return t;
3383 } else if (tvars1 == t.tvars) {
3384 return new ForAll(tvars1, qtype1) {
3385 @Override
3386 public boolean needsStripping() {
3387 return true;
3388 }
3389 };
3390 } else {
3391 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) {
3392 @Override
3393 public boolean needsStripping() {
3394 return true;
3395 }
3396 };
3397 }
3398 }
3399 }
3400
3401 public List<Type> substBounds(List<Type> tvars,
3402 List<Type> from,
3403 List<Type> to) {
3404 if (tvars.isEmpty())
3405 return tvars;
3406 ListBuffer<Type> newBoundsBuf = new ListBuffer<>();
3407 boolean changed = false;
3408 // calculate new bounds
3409 for (Type t : tvars) {
3410 TypeVar tv = (TypeVar) t;
3411 Type bound = subst(tv.getUpperBound(), from, to);
3412 if (bound != tv.getUpperBound())
3413 changed = true;
3414 newBoundsBuf.append(bound);
3415 }
3416 if (!changed)
3417 return tvars;
3418 ListBuffer<Type> newTvars = new ListBuffer<>();
3419 // create new type variables without bounds
3420 for (Type t : tvars) {
3421 newTvars.append(new TypeVar(t.tsym, null, syms.botType,
3422 t.getMetadata()));
3423 }
3424 // the new bounds should use the new type variables in place
3425 // of the old
3426 List<Type> newBounds = newBoundsBuf.toList();
3427 from = tvars;
3428 to = newTvars.toList();
3429 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
3430 newBounds.head = subst(newBounds.head, from, to);
3431 }
3432 newBounds = newBoundsBuf.toList();
3433 // set the bounds of new type variables to the new bounds
3434 for (Type t : newTvars.toList()) {
3435 TypeVar tv = (TypeVar) t;
3436 tv.setUpperBound( newBounds.head );
3437 newBounds = newBounds.tail;
3438 }
3439 return newTvars.toList();
3440 }
3441
3442 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
3443 Type bound1 = subst(t.getUpperBound(), from, to);
3444 if (bound1 == t.getUpperBound())
3445 return t;
3446 else {
3447 // create new type variable without bounds
3448 TypeVar tv = new TypeVar(t.tsym, null, syms.botType,
3449 t.getMetadata());
3450 // the new bound should use the new type variable in place
3451 // of the old
3452 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) );
3453 return tv;
3454 }
3455 }
3456 // </editor-fold>
3457
3458 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
3459 /**
3460 * Does t have the same bounds for quantified variables as s?
3461 */
3462 public boolean hasSameBounds(ForAll t, ForAll s) {
3463 List<Type> l1 = t.tvars;
3464 List<Type> l2 = s.tvars;
3465 while (l1.nonEmpty() && l2.nonEmpty() &&
3466 isSameType(l1.head.getUpperBound(),
3467 subst(l2.head.getUpperBound(),
3468 s.tvars,
3469 t.tvars))) {
3470 l1 = l1.tail;
3471 l2 = l2.tail;
3472 }
3473 return l1.isEmpty() && l2.isEmpty();
3474 }
3475 // </editor-fold>
3476
3477 // <editor-fold defaultstate="collapsed" desc="newInstances">
3478 /** Create new vector of type variables from list of variables
3479 * changing all recursive bounds from old to new list.
3480 */
3481 public List<Type> newInstances(List<Type> tvars) {
3482 List<Type> tvars1 = tvars.map(newInstanceFun);
3483 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
3484 TypeVar tv = (TypeVar) l.head;
3485 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) );
3486 }
3487 return tvars1;
3488 }
3489 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() {
3490 @Override
3491 public TypeVar visitTypeVar(TypeVar t, Void _unused) {
3492 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata());
3493 }
3494 };
3495 // </editor-fold>
3496
3497 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
3498 return original.accept(methodWithParameters, newParams);
3499 }
3500 // where
3501 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
3502 public Type visitType(Type t, List<Type> newParams) {
3503 throw new IllegalArgumentException("Not a method type: " + t);
3504 }
3505 public Type visitMethodType(MethodType t, List<Type> newParams) {
3506 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
3507 }
3508 public Type visitForAll(ForAll t, List<Type> newParams) {
3509 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
3510 }
3511 };
3512
3513 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
3514 return original.accept(methodWithThrown, newThrown);
3515 }
3516 // where
3517 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
3518 public Type visitType(Type t, List<Type> newThrown) {
3519 throw new IllegalArgumentException("Not a method type: " + t);
3520 }
3521 public Type visitMethodType(MethodType t, List<Type> newThrown) {
3522 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
3523 }
3524 public Type visitForAll(ForAll t, List<Type> newThrown) {
3525 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
3526 }
3527 };
3528
3529 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
3530 return original.accept(methodWithReturn, newReturn);
3531 }
3532 // where
3533 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
3534 public Type visitType(Type t, Type newReturn) {
3535 throw new IllegalArgumentException("Not a method type: " + t);
3536 }
3537 public Type visitMethodType(MethodType t, Type newReturn) {
3538 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) {
3539 @Override
3540 public Type baseType() {
3541 return t;
3542 }
3543 };
3544 }
3545 public Type visitForAll(ForAll t, Type newReturn) {
3546 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) {
3547 @Override
3548 public Type baseType() {
3549 return t;
3550 }
3551 };
3552 }
3553 };
3554
3555 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3556 public Type createErrorType(Type originalType) {
3557 return new ErrorType(originalType, syms.errSymbol);
3558 }
3559
3560 public Type createErrorType(ClassSymbol c, Type originalType) {
3561 return new ErrorType(c, originalType);
3562 }
3563
3564 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3565 return new ErrorType(name, container, originalType);
3566 }
3567 // </editor-fold>
3568
3569 // <editor-fold defaultstate="collapsed" desc="rank">
3570 /**
3571 * The rank of a class is the length of the longest path between
3572 * the class and java.lang.Object in the class inheritance
3573 * graph. Undefined for all but reference types.
3574 */
3575 public int rank(Type t) {
3576 switch(t.getTag()) {
3577 case CLASS: {
3578 ClassType cls = (ClassType)t;
3579 if (cls.rank_field < 0) {
3580 Name fullname = cls.tsym.getQualifiedName();
3581 if (fullname == names.java_lang_Object)
3582 cls.rank_field = 0;
3583 else {
3584 int r = rank(supertype(cls));
3585 for (List<Type> l = interfaces(cls);
3586 l.nonEmpty();
3587 l = l.tail) {
3588 if (rank(l.head) > r)
3589 r = rank(l.head);
3590 }
3591 cls.rank_field = r + 1;
3592 }
3593 }
3594 return cls.rank_field;
3595 }
3596 case TYPEVAR: {
3597 TypeVar tvar = (TypeVar)t;
3598 if (tvar.rank_field < 0) {
3599 int r = rank(supertype(tvar));
3600 for (List<Type> l = interfaces(tvar);
3601 l.nonEmpty();
3602 l = l.tail) {
3603 if (rank(l.head) > r) r = rank(l.head);
3604 }
3605 tvar.rank_field = r + 1;
3606 }
3607 return tvar.rank_field;
3608 }
3609 case ERROR:
3610 case NONE:
3611 return 0;
3612 default:
3613 throw new AssertionError();
3614 }
3615 }
3616 // </editor-fold>
3617
3618 /**
3619 * Helper method for generating a string representation of a given type
3620 * accordingly to a given locale
3621 */
3622 public String toString(Type t, Locale locale) {
3623 return Printer.createStandardPrinter(messages).visit(t, locale);
3624 }
3625
3626 /**
3627 * Helper method for generating a string representation of a given type
3628 * accordingly to a given locale
3629 */
3630 public String toString(Symbol t, Locale locale) {
3631 return Printer.createStandardPrinter(messages).visit(t, locale);
3632 }
3633
3634 // <editor-fold defaultstate="collapsed" desc="toString">
3635 /**
3636 * This toString is slightly more descriptive than the one on Type.
3637 *
3638 * @deprecated Types.toString(Type t, Locale l) provides better support
3639 * for localization
3640 */
3641 @Deprecated
3642 public String toString(Type t) {
3643 if (t.hasTag(FORALL)) {
3644 ForAll forAll = (ForAll)t;
3645 return typaramsString(forAll.tvars) + forAll.qtype;
3646 }
3647 return "" + t;
3648 }
3649 // where
3650 private String typaramsString(List<Type> tvars) {
3651 StringBuilder s = new StringBuilder();
3652 s.append('<');
3653 boolean first = true;
3654 for (Type t : tvars) {
3655 if (!first) s.append(", ");
3656 first = false;
3657 appendTyparamString(((TypeVar)t), s);
3658 }
3659 s.append('>');
3660 return s.toString();
3661 }
3662 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3663 buf.append(t);
3664 if (t.getUpperBound() == null ||
3665 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object)
3666 return;
3667 buf.append(" extends "); // Java syntax; no need for i18n
3668 Type bound = t.getUpperBound();
3669 if (!bound.isCompound()) {
3670 buf.append(bound);
3671 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3672 buf.append(supertype(t));
3673 for (Type intf : interfaces(t)) {
3674 buf.append('&');
3675 buf.append(intf);
3676 }
3677 } else {
3678 // No superclass was given in bounds.
3679 // In this case, supertype is Object, erasure is first interface.
3680 boolean first = true;
3681 for (Type intf : interfaces(t)) {
3682 if (!first) buf.append('&');
3683 first = false;
3684 buf.append(intf);
3685 }
3686 }
3687 }
3688 // </editor-fold>
3689
3690 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3691 /**
3692 * A cache for closures.
3693 *
3694 * <p>A closure is a list of all the supertypes and interfaces of
3695 * a class or interface type, ordered by ClassSymbol.precedes
3696 * (that is, subclasses come first, arbitrarily but fixed
3697 * otherwise).
3698 */
3699 private Map<Type,List<Type>> closureCache = new HashMap<>();
3700
3701 /**
3702 * Returns the closure of a class or interface type.
3703 */
3704 public List<Type> closure(Type t) {
3705 List<Type> cl = closureCache.get(t);
3706 if (cl == null) {
3707 Type st = supertype(t);
3708 if (!t.isCompound()) {
3709 if (st.hasTag(CLASS)) {
3710 cl = insert(closure(st), t);
3711 } else if (st.hasTag(TYPEVAR)) {
3712 cl = closure(st).prepend(t);
3713 } else {
3714 cl = List.of(t);
3715 }
3716 } else {
3717 cl = closure(supertype(t));
3718 }
3719 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3720 cl = union(cl, closure(l.head));
3721 closureCache.put(t, cl);
3722 }
3723 return cl;
3724 }
3725
3726 /**
3727 * Collect types into a new closure (using a {@code ClosureHolder})
3728 */
3729 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3730 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip),
3731 ClosureHolder::add,
3732 ClosureHolder::merge,
3733 ClosureHolder::closure);
3734 }
3735 //where
3736 class ClosureHolder {
3737 List<Type> closure;
3738 final boolean minClosure;
3739 final BiPredicate<Type, Type> shouldSkip;
3740
3741 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3742 this.closure = List.nil();
3743 this.minClosure = minClosure;
3744 this.shouldSkip = shouldSkip;
3745 }
3746
3747 void add(Type type) {
3748 closure = insert(closure, type, shouldSkip);
3749 }
3750
3751 ClosureHolder merge(ClosureHolder other) {
3752 closure = union(closure, other.closure, shouldSkip);
3753 return this;
3754 }
3755
3756 List<Type> closure() {
3757 return minClosure ? closureMin(closure) : closure;
3758 }
3759 }
3760
3761 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym;
3762
3763 /**
3764 * Insert a type in a closure
3765 */
3766 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) {
3767 if (cl.isEmpty()) {
3768 return cl.prepend(t);
3769 } else if (shouldSkip.test(t, cl.head)) {
3770 return cl;
3771 } else if (t.tsym.precedes(cl.head.tsym, this)) {
3772 return cl.prepend(t);
3773 } else {
3774 // t comes after head, or the two are unrelated
3775 return insert(cl.tail, t, shouldSkip).prepend(cl.head);
3776 }
3777 }
3778
3779 public List<Type> insert(List<Type> cl, Type t) {
3780 return insert(cl, t, basicClosureSkip);
3781 }
3782
3783 /**
3784 * Form the union of two closures
3785 */
3786 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) {
3787 if (cl1.isEmpty()) {
3788 return cl2;
3789 } else if (cl2.isEmpty()) {
3790 return cl1;
3791 } else if (shouldSkip.test(cl1.head, cl2.head)) {
3792 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
3793 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3794 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
3795 } else {
3796 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
3797 }
3798 }
3799
3800 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3801 return union(cl1, cl2, basicClosureSkip);
3802 }
3803
3804 /**
3805 * Intersect two closures
3806 */
3807 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3808 if (cl1 == cl2)
3809 return cl1;
3810 if (cl1.isEmpty() || cl2.isEmpty())
3811 return List.nil();
3812 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3813 return intersect(cl1.tail, cl2);
3814 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3815 return intersect(cl1, cl2.tail);
3816 if (isSameType(cl1.head, cl2.head))
3817 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3818 if (cl1.head.tsym == cl2.head.tsym &&
3819 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) {
3820 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3821 Type merge = merge(cl1.head,cl2.head);
3822 return intersect(cl1.tail, cl2.tail).prepend(merge);
3823 }
3824 if (cl1.head.isRaw() || cl2.head.isRaw())
3825 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3826 }
3827 return intersect(cl1.tail, cl2.tail);
3828 }
3829 // where
3830 class TypePair {
3831 final Type t1;
3832 final Type t2;;
3833
3834 TypePair(Type t1, Type t2) {
3835 this.t1 = t1;
3836 this.t2 = t2;
3837 }
3838 @Override
3839 public int hashCode() {
3840 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3841 }
3842 @Override
3843 public boolean equals(Object obj) {
3844 return (obj instanceof TypePair typePair)
3845 && isSameType(t1, typePair.t1)
3846 && isSameType(t2, typePair.t2);
3847 }
3848 }
3849 Set<TypePair> mergeCache = new HashSet<>();
3850 private Type merge(Type c1, Type c2) {
3851 ClassType class1 = (ClassType) c1;
3852 List<Type> act1 = class1.getTypeArguments();
3853 ClassType class2 = (ClassType) c2;
3854 List<Type> act2 = class2.getTypeArguments();
3855 ListBuffer<Type> merged = new ListBuffer<>();
3856 List<Type> typarams = class1.tsym.type.getTypeArguments();
3857
3858 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3859 if (containsType(act1.head, act2.head)) {
3860 merged.append(act1.head);
3861 } else if (containsType(act2.head, act1.head)) {
3862 merged.append(act2.head);
3863 } else {
3864 TypePair pair = new TypePair(c1, c2);
3865 Type m;
3866 if (mergeCache.add(pair)) {
3867 m = new WildcardType(lub(wildUpperBound(act1.head),
3868 wildUpperBound(act2.head)),
3869 BoundKind.EXTENDS,
3870 syms.boundClass);
3871 mergeCache.remove(pair);
3872 } else {
3873 m = new WildcardType(syms.objectType,
3874 BoundKind.UNBOUND,
3875 syms.boundClass);
3876 }
3877 merged.append(m.withTypeVar(typarams.head));
3878 }
3879 act1 = act1.tail;
3880 act2 = act2.tail;
3881 typarams = typarams.tail;
3882 }
3883 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3884 // There is no spec detailing how type annotations are to
3885 // be inherited. So set it to noAnnotations for now
3886 return new ClassType(class1.getEnclosingType(), merged.toList(),
3887 class1.tsym);
3888 }
3889
3890 /**
3891 * Return the minimum type of a closure, a compound type if no
3892 * unique minimum exists.
3893 */
3894 private Type compoundMin(List<Type> cl) {
3895 if (cl.isEmpty()) return syms.objectType;
3896 List<Type> compound = closureMin(cl);
3897 if (compound.isEmpty())
3898 return null;
3899 else if (compound.tail.isEmpty())
3900 return compound.head;
3901 else
3902 return makeIntersectionType(compound);
3903 }
3904
3905 /**
3906 * Return the minimum types of a closure, suitable for computing
3907 * compoundMin or glb.
3908 */
3909 private List<Type> closureMin(List<Type> cl) {
3910 ListBuffer<Type> classes = new ListBuffer<>();
3911 ListBuffer<Type> interfaces = new ListBuffer<>();
3912 Set<Type> toSkip = new HashSet<>();
3913 while (!cl.isEmpty()) {
3914 Type current = cl.head;
3915 boolean keep = !toSkip.contains(current);
3916 if (keep && current.hasTag(TYPEVAR)) {
3917 // skip lower-bounded variables with a subtype in cl.tail
3918 for (Type t : cl.tail) {
3919 if (isSubtypeNoCapture(t, current)) {
3920 keep = false;
3921 break;
3922 }
3923 }
3924 }
3925 if (keep) {
3926 if (current.isInterface())
3927 interfaces.append(current);
3928 else
3929 classes.append(current);
3930 for (Type t : cl.tail) {
3931 // skip supertypes of 'current' in cl.tail
3932 if (isSubtypeNoCapture(current, t))
3933 toSkip.add(t);
3934 }
3935 }
3936 cl = cl.tail;
3937 }
3938 return classes.appendList(interfaces).toList();
3939 }
3940
3941 /**
3942 * Return the least upper bound of list of types. if the lub does
3943 * not exist return null.
3944 */
3945 public Type lub(List<Type> ts) {
3946 return lub(ts.toArray(new Type[ts.length()]));
3947 }
3948
3949 /**
3950 * Return the least upper bound (lub) of set of types. If the lub
3951 * does not exist return the type of null (bottom).
3952 */
3953 public Type lub(Type... ts) {
3954 final int UNKNOWN_BOUND = 0;
3955 final int ARRAY_BOUND = 1;
3956 final int CLASS_BOUND = 2;
3957
3958 int[] kinds = new int[ts.length];
3959
3960 int boundkind = UNKNOWN_BOUND;
3961 for (int i = 0 ; i < ts.length ; i++) {
3962 Type t = ts[i];
3963 switch (t.getTag()) {
3964 case CLASS:
3965 boundkind |= kinds[i] = CLASS_BOUND;
3966 break;
3967 case ARRAY:
3968 boundkind |= kinds[i] = ARRAY_BOUND;
3969 break;
3970 case TYPEVAR:
3971 do {
3972 t = t.getUpperBound();
3973 } while (t.hasTag(TYPEVAR));
3974 if (t.hasTag(ARRAY)) {
3975 boundkind |= kinds[i] = ARRAY_BOUND;
3976 } else {
3977 boundkind |= kinds[i] = CLASS_BOUND;
3978 }
3979 break;
3980 default:
3981 kinds[i] = UNKNOWN_BOUND;
3982 if (t.isPrimitive())
3983 return syms.errType;
3984 }
3985 }
3986 switch (boundkind) {
3987 case 0:
3988 return syms.botType;
3989
3990 case ARRAY_BOUND:
3991 // calculate lub(A[], B[])
3992 Type[] elements = new Type[ts.length];
3993 for (int i = 0 ; i < ts.length ; i++) {
3994 Type elem = elements[i] = elemTypeFun.apply(ts[i]);
3995 if (elem.isPrimitive()) {
3996 // if a primitive type is found, then return
3997 // arraySuperType unless all the types are the
3998 // same
3999 Type first = ts[0];
4000 for (int j = 1 ; j < ts.length ; j++) {
4001 if (!isSameType(first, ts[j])) {
4002 // lub(int[], B[]) is Cloneable & Serializable
4003 return arraySuperType();
4004 }
4005 }
4006 // all the array types are the same, return one
4007 // lub(int[], int[]) is int[]
4008 return first;
4009 }
4010 }
4011 // lub(A[], B[]) is lub(A, B)[]
4012 return new ArrayType(lub(elements), syms.arrayClass);
4013
4014 case CLASS_BOUND:
4015 // calculate lub(A, B)
4016 int startIdx = 0;
4017 for (int i = 0; i < ts.length ; i++) {
4018 Type t = ts[i];
4019 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) {
4020 break;
4021 } else {
4022 startIdx++;
4023 }
4024 }
4025 Assert.check(startIdx < ts.length);
4026 //step 1 - compute erased candidate set (EC)
4027 List<Type> cl = erasedSupertypes(ts[startIdx]);
4028 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4029 Type t = ts[i];
4030 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
4031 cl = intersect(cl, erasedSupertypes(t));
4032 }
4033 //step 2 - compute minimal erased candidate set (MEC)
4034 List<Type> mec = closureMin(cl);
4035 //step 3 - for each element G in MEC, compute lci(Inv(G))
4036 List<Type> candidates = List.nil();
4037 for (Type erasedSupertype : mec) {
4038 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
4039 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4040 Type superType = asSuper(ts[i], erasedSupertype.tsym);
4041 lci = intersect(lci, superType != null ? List.of(superType) : List.nil());
4042 }
4043 candidates = candidates.appendList(lci);
4044 }
4045 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
4046 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
4047 return compoundMin(candidates);
4048
4049 default:
4050 // calculate lub(A, B[])
4051 List<Type> classes = List.of(arraySuperType());
4052 for (int i = 0 ; i < ts.length ; i++) {
4053 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays
4054 classes = classes.prepend(ts[i]);
4055 }
4056 // lub(A, B[]) is lub(A, arraySuperType)
4057 return lub(classes);
4058 }
4059 }
4060 // where
4061 List<Type> erasedSupertypes(Type t) {
4062 ListBuffer<Type> buf = new ListBuffer<>();
4063 for (Type sup : closure(t)) {
4064 if (sup.hasTag(TYPEVAR)) {
4065 buf.append(sup);
4066 } else {
4067 buf.append(erasure(sup));
4068 }
4069 }
4070 return buf.toList();
4071 }
4072
4073 private Type arraySuperType;
4074 private Type arraySuperType() {
4075 // initialized lazily to avoid problems during compiler startup
4076 if (arraySuperType == null) {
4077 // JLS 10.8: all arrays implement Cloneable and Serializable.
4078 arraySuperType = makeIntersectionType(List.of(syms.serializableType,
4079 syms.cloneableType), true);
4080 }
4081 return arraySuperType;
4082 }
4083 // </editor-fold>
4084
4085 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
4086 public Type glb(List<Type> ts) {
4087 Type t1 = ts.head;
4088 for (Type t2 : ts.tail) {
4089 if (t1.isErroneous())
4090 return t1;
4091 t1 = glb(t1, t2);
4092 }
4093 return t1;
4094 }
4095 //where
4096 public Type glb(Type t, Type s) {
4097 if (s == null)
4098 return t;
4099 else if (t.isPrimitive() || s.isPrimitive())
4100 return syms.errType;
4101 else if (isSubtypeNoCapture(t, s))
4102 return t;
4103 else if (isSubtypeNoCapture(s, t))
4104 return s;
4105
4106 List<Type> closure = union(closure(t), closure(s));
4107 return glbFlattened(closure, t);
4108 }
4109 //where
4110 /**
4111 * Perform glb for a list of non-primitive, non-error, non-compound types;
4112 * redundant elements are removed. Bounds should be ordered according to
4113 * {@link Symbol#precedes(TypeSymbol,Types)}.
4114 *
4115 * @param flatBounds List of type to glb
4116 * @param errT Original type to use if the result is an error type
4117 */
4118 private Type glbFlattened(List<Type> flatBounds, Type errT) {
4119 List<Type> bounds = closureMin(flatBounds);
4120
4121 if (bounds.isEmpty()) { // length == 0
4122 return syms.objectType;
4123 } else if (bounds.tail.isEmpty()) { // length == 1
4124 return bounds.head;
4125 } else { // length > 1
4126 int classCount = 0;
4127 List<Type> cvars = List.nil();
4128 List<Type> lowers = List.nil();
4129 for (Type bound : bounds) {
4130 if (!bound.isInterface()) {
4131 classCount++;
4132 Type lower = cvarLowerBound(bound);
4133 if (bound != lower && !lower.hasTag(BOT)) {
4134 cvars = cvars.append(bound);
4135 lowers = lowers.append(lower);
4136 }
4137 }
4138 }
4139 if (classCount > 1) {
4140 if (lowers.isEmpty()) {
4141 return createErrorType(errT);
4142 } else {
4143 // try again with lower bounds included instead of capture variables
4144 List<Type> newBounds = bounds.diff(cvars).appendList(lowers);
4145 return glb(newBounds);
4146 }
4147 }
4148 }
4149 return makeIntersectionType(bounds);
4150 }
4151 // </editor-fold>
4152
4153 // <editor-fold defaultstate="collapsed" desc="hashCode">
4154 /**
4155 * Compute a hash code on a type.
4156 */
4157 public int hashCode(Type t) {
4158 return hashCode(t, false);
4159 }
4160
4161 public int hashCode(Type t, boolean strict) {
4162 return strict ?
4163 hashCodeStrictVisitor.visit(t) :
4164 hashCodeVisitor.visit(t);
4165 }
4166 // where
4167 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor();
4168 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() {
4169 @Override
4170 public Integer visitTypeVar(TypeVar t, Void ignored) {
4171 return System.identityHashCode(t);
4172 }
4173 };
4174
4175 private static class HashCodeVisitor extends UnaryVisitor<Integer> {
4176 public Integer visitType(Type t, Void ignored) {
4177 return t.getTag().ordinal();
4178 }
4179
4180 @Override
4181 public Integer visitClassType(ClassType t, Void ignored) {
4182 int result = visit(t.getEnclosingType());
4183 result *= 127;
4184 result += t.tsym.flatName().hashCode();
4185 for (Type s : t.getTypeArguments()) {
4186 result *= 127;
4187 result += visit(s);
4188 }
4189 return result;
4190 }
4191
4192 @Override
4193 public Integer visitMethodType(MethodType t, Void ignored) {
4194 int h = METHOD.ordinal();
4195 for (List<Type> thisargs = t.argtypes;
4196 thisargs.tail != null;
4197 thisargs = thisargs.tail)
4198 h = (h << 5) + visit(thisargs.head);
4199 return (h << 5) + visit(t.restype);
4200 }
4201
4202 @Override
4203 public Integer visitWildcardType(WildcardType t, Void ignored) {
4204 int result = t.kind.hashCode();
4205 if (t.type != null) {
4206 result *= 127;
4207 result += visit(t.type);
4208 }
4209 return result;
4210 }
4211
4212 @Override
4213 public Integer visitArrayType(ArrayType t, Void ignored) {
4214 return visit(t.elemtype) + 12;
4215 }
4216
4217 @Override
4218 public Integer visitTypeVar(TypeVar t, Void ignored) {
4219 return System.identityHashCode(t);
4220 }
4221
4222 @Override
4223 public Integer visitUndetVar(UndetVar t, Void ignored) {
4224 return System.identityHashCode(t);
4225 }
4226
4227 @Override
4228 public Integer visitErrorType(ErrorType t, Void ignored) {
4229 return 0;
4230 }
4231 }
4232 // </editor-fold>
4233
4234 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
4235 /**
4236 * Does t have a result that is a subtype of the result type of s,
4237 * suitable for covariant returns? It is assumed that both types
4238 * are (possibly polymorphic) method types. Monomorphic method
4239 * types are handled in the obvious way. Polymorphic method types
4240 * require renaming all type variables of one to corresponding
4241 * type variables in the other, where correspondence is by
4242 * position in the type parameter list. */
4243 public boolean resultSubtype(Type t, Type s, Warner warner) {
4244 List<Type> tvars = t.getTypeArguments();
4245 List<Type> svars = s.getTypeArguments();
4246 Type tres = t.getReturnType();
4247 Type sres = subst(s.getReturnType(), svars, tvars);
4248 return covariantReturnType(tres, sres, warner);
4249 }
4250
4251 /**
4252 * Return-Type-Substitutable.
4253 * @jls 8.4.5 Method Result
4254 */
4255 public boolean returnTypeSubstitutable(Type r1, Type r2) {
4256 if (hasSameArgs(r1, r2))
4257 return resultSubtype(r1, r2, noWarnings);
4258 else
4259 return covariantReturnType(r1.getReturnType(),
4260 erasure(r2.getReturnType()),
4261 noWarnings);
4262 }
4263
4264 public boolean returnTypeSubstitutable(Type r1,
4265 Type r2, Type r2res,
4266 Warner warner) {
4267 if (isSameType(r1.getReturnType(), r2res))
4268 return true;
4269 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
4270 return false;
4271
4272 if (hasSameArgs(r1, r2))
4273 return covariantReturnType(r1.getReturnType(), r2res, warner);
4274 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
4275 return true;
4276 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
4277 return false;
4278 warner.warn(LintCategory.UNCHECKED);
4279 return true;
4280 }
4281
4282 /**
4283 * Is t an appropriate return type in an overrider for a
4284 * method that returns s?
4285 */
4286 public boolean covariantReturnType(Type t, Type s, Warner warner) {
4287 return
4288 isSameType(t, s) ||
4289 !t.isPrimitive() &&
4290 !s.isPrimitive() &&
4291 isAssignable(t, s, warner);
4292 }
4293 // </editor-fold>
4294
4295 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
4296 /**
4297 * Return the class that boxes the given primitive.
4298 */
4299 public ClassSymbol boxedClass(Type t) {
4300 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]);
4301 }
4302
4303 /**
4304 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
4305 */
4306 public Type boxedTypeOrType(Type t) {
4307 return t.isPrimitive() ?
4308 boxedClass(t).type :
4309 t;
4310 }
4311
4312 /**
4313 * Return the primitive type corresponding to a boxed type.
4314 */
4315 public Type unboxedType(Type t) {
4316 if (t.hasTag(ERROR))
4317 return Type.noType;
4318 for (int i=0; i<syms.boxedName.length; i++) {
4319 Name box = syms.boxedName[i];
4320 if (box != null &&
4321 asSuper(t, syms.enterClass(syms.java_base, box)) != null)
4322 return syms.typeOfTag[i];
4323 }
4324 return Type.noType;
4325 }
4326
4327 /**
4328 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
4329 */
4330 public Type unboxedTypeOrType(Type t) {
4331 Type unboxedType = unboxedType(t);
4332 return unboxedType.hasTag(NONE) ? t : unboxedType;
4333 }
4334 // </editor-fold>
4335
4336 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
4337 /*
4338 * JLS 5.1.10 Capture Conversion:
4339 *
4340 * Let G name a generic type declaration with n formal type
4341 * parameters A1 ... An with corresponding bounds U1 ... Un. There
4342 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
4343 * where, for 1 <= i <= n:
4344 *
4345 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
4346 * Si is a fresh type variable whose upper bound is
4347 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
4348 * type.
4349 *
4350 * + If Ti is a wildcard type argument of the form ? extends Bi,
4351 * then Si is a fresh type variable whose upper bound is
4352 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
4353 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
4354 * a compile-time error if for any two classes (not interfaces)
4355 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
4356 *
4357 * + If Ti is a wildcard type argument of the form ? super Bi,
4358 * then Si is a fresh type variable whose upper bound is
4359 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
4360 *
4361 * + Otherwise, Si = Ti.
4362 *
4363 * Capture conversion on any type other than a parameterized type
4364 * (4.5) acts as an identity conversion (5.1.1). Capture
4365 * conversions never require a special action at run time and
4366 * therefore never throw an exception at run time.
4367 *
4368 * Capture conversion is not applied recursively.
4369 */
4370 /**
4371 * Capture conversion as specified by the JLS.
4372 */
4373
4374 public List<Type> capture(List<Type> ts) {
4375 List<Type> buf = List.nil();
4376 for (Type t : ts) {
4377 buf = buf.prepend(capture(t));
4378 }
4379 return buf.reverse();
4380 }
4381
4382 public Type capture(Type t) {
4383 if (!t.hasTag(CLASS)) {
4384 return t;
4385 }
4386 if (t.getEnclosingType() != Type.noType) {
4387 Type capturedEncl = capture(t.getEnclosingType());
4388 if (capturedEncl != t.getEnclosingType()) {
4389 Type type1 = memberType(capturedEncl, t.tsym);
4390 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
4391 }
4392 }
4393 ClassType cls = (ClassType)t;
4394 if (cls.isRaw() || !cls.isParameterized())
4395 return cls;
4396
4397 ClassType G = (ClassType)cls.asElement().asType();
4398 List<Type> A = G.getTypeArguments();
4399 List<Type> T = cls.getTypeArguments();
4400 List<Type> S = freshTypeVariables(T);
4401
4402 List<Type> currentA = A;
4403 List<Type> currentT = T;
4404 List<Type> currentS = S;
4405 boolean captured = false;
4406 while (!currentA.isEmpty() &&
4407 !currentT.isEmpty() &&
4408 !currentS.isEmpty()) {
4409 if (currentS.head != currentT.head) {
4410 captured = true;
4411 WildcardType Ti = (WildcardType)currentT.head;
4412 Type Ui = currentA.head.getUpperBound();
4413 CapturedType Si = (CapturedType)currentS.head;
4414 if (Ui == null)
4415 Ui = syms.objectType;
4416 switch (Ti.kind) {
4417 case UNBOUND:
4418 Si.setUpperBound( subst(Ui, A, S) );
4419 Si.lower = syms.botType;
4420 break;
4421 case EXTENDS:
4422 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) );
4423 Si.lower = syms.botType;
4424 break;
4425 case SUPER:
4426 Si.setUpperBound( subst(Ui, A, S) );
4427 Si.lower = Ti.getSuperBound();
4428 break;
4429 }
4430 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound();
4431 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower;
4432 if (!Si.getUpperBound().hasTag(ERROR) &&
4433 !Si.lower.hasTag(ERROR) &&
4434 isSameType(tmpBound, tmpLower)) {
4435 currentS.head = Si.getUpperBound();
4436 }
4437 }
4438 currentA = currentA.tail;
4439 currentT = currentT.tail;
4440 currentS = currentS.tail;
4441 }
4442 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
4443 return erasure(t); // some "rare" type involved
4444
4445 if (captured)
4446 return new ClassType(cls.getEnclosingType(), S, cls.tsym,
4447 cls.getMetadata());
4448 else
4449 return t;
4450 }
4451 // where
4452 public List<Type> freshTypeVariables(List<Type> types) {
4453 ListBuffer<Type> result = new ListBuffer<>();
4454 for (Type t : types) {
4455 if (t.hasTag(WILDCARD)) {
4456 Type bound = ((WildcardType)t).getExtendsBound();
4457 if (bound == null)
4458 bound = syms.objectType;
4459 result.append(new CapturedType(capturedName,
4460 syms.noSymbol,
4461 bound,
4462 syms.botType,
4463 (WildcardType)t));
4464 } else {
4465 result.append(t);
4466 }
4467 }
4468 return result.toList();
4469 }
4470 // </editor-fold>
4471
4472 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
4473 private boolean sideCast(Type from, Type to, Warner warn) {
4474 // We are casting from type $from$ to type $to$, which are
4475 // non-final unrelated types. This method
4476 // tries to reject a cast by transferring type parameters
4477 // from $to$ to $from$ by common superinterfaces.
4478 boolean reverse = false;
4479 Type target = to;
4480 if ((to.tsym.flags() & INTERFACE) == 0) {
4481 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4482 reverse = true;
4483 to = from;
4484 from = target;
4485 }
4486 List<Type> commonSupers = superClosure(to, erasure(from));
4487 boolean giveWarning = commonSupers.isEmpty();
4488 // The arguments to the supers could be unified here to
4489 // get a more accurate analysis
4490 while (commonSupers.nonEmpty()) {
4491 Type t1 = asSuper(from, commonSupers.head.tsym);
4492 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
4493 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4494 return false;
4495 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
4496 commonSupers = commonSupers.tail;
4497 }
4498 if (giveWarning && !isReifiable(reverse ? from : to))
4499 warn.warn(LintCategory.UNCHECKED);
4500 return true;
4501 }
4502
4503 private boolean sideCastFinal(Type from, Type to, Warner warn) {
4504 // We are casting from type $from$ to type $to$, which are
4505 // unrelated types one of which is final and the other of
4506 // which is an interface. This method
4507 // tries to reject a cast by transferring type parameters
4508 // from the final class to the interface.
4509 boolean reverse = false;
4510 Type target = to;
4511 if ((to.tsym.flags() & INTERFACE) == 0) {
4512 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4513 reverse = true;
4514 to = from;
4515 from = target;
4516 }
4517 Assert.check((from.tsym.flags() & FINAL) != 0);
4518 Type t1 = asSuper(from, to.tsym);
4519 if (t1 == null) return false;
4520 Type t2 = to;
4521 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4522 return false;
4523 if (!isReifiable(target) &&
4524 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
4525 warn.warn(LintCategory.UNCHECKED);
4526 return true;
4527 }
4528
4529 private boolean giveWarning(Type from, Type to) {
4530 List<Type> bounds = to.isCompound() ?
4531 directSupertypes(to) : List.of(to);
4532 for (Type b : bounds) {
4533 Type subFrom = asSub(from, b.tsym);
4534 if (b.isParameterized() &&
4535 (!(isUnbounded(b) ||
4536 isSubtype(from, b) ||
4537 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
4538 return true;
4539 }
4540 }
4541 return false;
4542 }
4543
4544 private List<Type> superClosure(Type t, Type s) {
4545 List<Type> cl = List.nil();
4546 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
4547 if (isSubtype(s, erasure(l.head))) {
4548 cl = insert(cl, l.head);
4549 } else {
4550 cl = union(cl, superClosure(l.head, s));
4551 }
4552 }
4553 return cl;
4554 }
4555
4556 private boolean containsTypeEquivalent(Type t, Type s) {
4557 return isSameType(t, s) || // shortcut
4558 containsType(t, s) && containsType(s, t);
4559 }
4560
4561 // <editor-fold defaultstate="collapsed" desc="adapt">
4562 /**
4563 * Adapt a type by computing a substitution which maps a source
4564 * type to a target type.
4565 *
4566 * @param source the source type
4567 * @param target the target type
4568 * @param from the type variables of the computed substitution
4569 * @param to the types of the computed substitution.
4570 */
4571 public void adapt(Type source,
4572 Type target,
4573 ListBuffer<Type> from,
4574 ListBuffer<Type> to) throws AdaptFailure {
4575 new Adapter(from, to).adapt(source, target);
4576 }
4577
4578 class Adapter extends SimpleVisitor<Void, Type> {
4579
4580 ListBuffer<Type> from;
4581 ListBuffer<Type> to;
4582 Map<Symbol,Type> mapping;
4583
4584 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
4585 this.from = from;
4586 this.to = to;
4587 mapping = new HashMap<>();
4588 }
4589
4590 public void adapt(Type source, Type target) throws AdaptFailure {
4591 visit(source, target);
4592 List<Type> fromList = from.toList();
4593 List<Type> toList = to.toList();
4594 while (!fromList.isEmpty()) {
4595 Type val = mapping.get(fromList.head.tsym);
4596 if (toList.head != val)
4597 toList.head = val;
4598 fromList = fromList.tail;
4599 toList = toList.tail;
4600 }
4601 }
4602
4603 @Override
4604 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
4605 if (target.hasTag(CLASS))
4606 adaptRecursive(source.allparams(), target.allparams());
4607 return null;
4608 }
4609
4610 @Override
4611 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
4612 if (target.hasTag(ARRAY))
4613 adaptRecursive(elemtype(source), elemtype(target));
4614 return null;
4615 }
4616
4617 @Override
4618 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
4619 if (source.isExtendsBound())
4620 adaptRecursive(wildUpperBound(source), wildUpperBound(target));
4621 else if (source.isSuperBound())
4622 adaptRecursive(wildLowerBound(source), wildLowerBound(target));
4623 return null;
4624 }
4625
4626 @Override
4627 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
4628 // Check to see if there is
4629 // already a mapping for $source$, in which case
4630 // the old mapping will be merged with the new
4631 Type val = mapping.get(source.tsym);
4632 if (val != null) {
4633 if (val.isSuperBound() && target.isSuperBound()) {
4634 val = isSubtype(wildLowerBound(val), wildLowerBound(target))
4635 ? target : val;
4636 } else if (val.isExtendsBound() && target.isExtendsBound()) {
4637 val = isSubtype(wildUpperBound(val), wildUpperBound(target))
4638 ? val : target;
4639 } else if (!isSameType(val, target)) {
4640 throw new AdaptFailure();
4641 }
4642 } else {
4643 val = target;
4644 from.append(source);
4645 to.append(target);
4646 }
4647 mapping.put(source.tsym, val);
4648 return null;
4649 }
4650
4651 @Override
4652 public Void visitType(Type source, Type target) {
4653 return null;
4654 }
4655
4656 private Set<TypePair> cache = new HashSet<>();
4657
4658 private void adaptRecursive(Type source, Type target) {
4659 TypePair pair = new TypePair(source, target);
4660 if (cache.add(pair)) {
4661 try {
4662 visit(source, target);
4663 } finally {
4664 cache.remove(pair);
4665 }
4666 }
4667 }
4668
4669 private void adaptRecursive(List<Type> source, List<Type> target) {
4670 if (source.length() == target.length()) {
4671 while (source.nonEmpty()) {
4672 adaptRecursive(source.head, target.head);
4673 source = source.tail;
4674 target = target.tail;
4675 }
4676 }
4677 }
4678 }
4679
4680 public static class AdaptFailure extends RuntimeException {
4681 static final long serialVersionUID = -7490231548272701566L;
4682 }
4683
4684 private void adaptSelf(Type t,
4685 ListBuffer<Type> from,
4686 ListBuffer<Type> to) {
4687 try {
4688 //if (t.tsym.type != t)
4689 adapt(t.tsym.type, t, from, to);
4690 } catch (AdaptFailure ex) {
4691 // Adapt should never fail calculating a mapping from
4692 // t.tsym.type to t as there can be no merge problem.
4693 throw new AssertionError(ex);
4694 }
4695 }
4696 // </editor-fold>
4697
4698 /**
4699 * Rewrite all type variables (universal quantifiers) in the given
4700 * type to wildcards (existential quantifiers). This is used to
4701 * determine if a cast is allowed. For example, if high is true
4702 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4703 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4704 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4705 * List<Integer>} with a warning.
4706 * @param t a type
4707 * @param high if true return an upper bound; otherwise a lower
4708 * bound
4709 * @param rewriteTypeVars only rewrite captured wildcards if false;
4710 * otherwise rewrite all type variables
4711 * @return the type rewritten with wildcards (existential
4712 * quantifiers) only
4713 */
4714 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4715 return new Rewriter(high, rewriteTypeVars).visit(t);
4716 }
4717
4718 class Rewriter extends UnaryVisitor<Type> {
4719
4720 boolean high;
4721 boolean rewriteTypeVars;
4722
4723 Rewriter(boolean high, boolean rewriteTypeVars) {
4724 this.high = high;
4725 this.rewriteTypeVars = rewriteTypeVars;
4726 }
4727
4728 @Override
4729 public Type visitClassType(ClassType t, Void s) {
4730 ListBuffer<Type> rewritten = new ListBuffer<>();
4731 boolean changed = false;
4732 for (Type arg : t.allparams()) {
4733 Type bound = visit(arg);
4734 if (arg != bound) {
4735 changed = true;
4736 }
4737 rewritten.append(bound);
4738 }
4739 if (changed)
4740 return subst(t.tsym.type,
4741 t.tsym.type.allparams(),
4742 rewritten.toList());
4743 else
4744 return t;
4745 }
4746
4747 public Type visitType(Type t, Void s) {
4748 return t;
4749 }
4750
4751 @Override
4752 public Type visitCapturedType(CapturedType t, Void s) {
4753 Type w_bound = t.wildcard.type;
4754 Type bound = w_bound.contains(t) ?
4755 erasure(w_bound) :
4756 visit(w_bound);
4757 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4758 }
4759
4760 @Override
4761 public Type visitTypeVar(TypeVar t, Void s) {
4762 if (rewriteTypeVars) {
4763 Type bound = t.getUpperBound().contains(t) ?
4764 erasure(t.getUpperBound()) :
4765 visit(t.getUpperBound());
4766 return rewriteAsWildcardType(bound, t, EXTENDS);
4767 } else {
4768 return t;
4769 }
4770 }
4771
4772 @Override
4773 public Type visitWildcardType(WildcardType t, Void s) {
4774 Type bound2 = visit(t.type);
4775 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4776 }
4777
4778 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4779 switch (bk) {
4780 case EXTENDS: return high ?
4781 makeExtendsWildcard(B(bound), formal) :
4782 makeExtendsWildcard(syms.objectType, formal);
4783 case SUPER: return high ?
4784 makeSuperWildcard(syms.botType, formal) :
4785 makeSuperWildcard(B(bound), formal);
4786 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4787 default:
4788 Assert.error("Invalid bound kind " + bk);
4789 return null;
4790 }
4791 }
4792
4793 Type B(Type t) {
4794 while (t.hasTag(WILDCARD)) {
4795 WildcardType w = (WildcardType)t;
4796 t = high ?
4797 w.getExtendsBound() :
4798 w.getSuperBound();
4799 if (t == null) {
4800 t = high ? syms.objectType : syms.botType;
4801 }
4802 }
4803 return t;
4804 }
4805 }
4806
4807
4808 /**
4809 * Create a wildcard with the given upper (extends) bound; create
4810 * an unbounded wildcard if bound is Object.
4811 *
4812 * @param bound the upper bound
4813 * @param formal the formal type parameter that will be
4814 * substituted by the wildcard
4815 */
4816 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4817 if (bound == syms.objectType) {
4818 return new WildcardType(syms.objectType,
4819 BoundKind.UNBOUND,
4820 syms.boundClass,
4821 formal);
4822 } else {
4823 return new WildcardType(bound,
4824 BoundKind.EXTENDS,
4825 syms.boundClass,
4826 formal);
4827 }
4828 }
4829
4830 /**
4831 * Create a wildcard with the given lower (super) bound; create an
4832 * unbounded wildcard if bound is bottom (type of {@code null}).
4833 *
4834 * @param bound the lower bound
4835 * @param formal the formal type parameter that will be
4836 * substituted by the wildcard
4837 */
4838 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4839 if (bound.hasTag(BOT)) {
4840 return new WildcardType(syms.objectType,
4841 BoundKind.UNBOUND,
4842 syms.boundClass,
4843 formal);
4844 } else {
4845 return new WildcardType(bound,
4846 BoundKind.SUPER,
4847 syms.boundClass,
4848 formal);
4849 }
4850 }
4851
4852 /**
4853 * A wrapper for a type that allows use in sets.
4854 */
4855 public static class UniqueType {
4856 public final Type type;
4857 final Types types;
4858
4859 public UniqueType(Type type, Types types) {
4860 this.type = type;
4861 this.types = types;
4862 }
4863
4864 public int hashCode() {
4865 return types.hashCode(type);
4866 }
4867
4868 public boolean equals(Object obj) {
4869 return (obj instanceof UniqueType uniqueType) &&
4870 types.isSameType(type, uniqueType.type);
4871 }
4872
4873 public String toString() {
4874 return type.toString();
4875 }
4876
4877 }
4878 // </editor-fold>
4879
4880 // <editor-fold defaultstate="collapsed" desc="Visitors">
4881 /**
4882 * A default visitor for types. All visitor methods except
4883 * visitType are implemented by delegating to visitType. Concrete
4884 * subclasses must provide an implementation of visitType and can
4885 * override other methods as needed.
4886 *
4887 * @param <R> the return type of the operation implemented by this
4888 * visitor; use Void if no return type is needed.
4889 * @param <S> the type of the second argument (the first being the
4890 * type itself) of the operation implemented by this visitor; use
4891 * Void if a second argument is not needed.
4892 */
4893 public abstract static class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4894 public final R visit(Type t, S s) { return t.accept(this, s); }
4895 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4896 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4897 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4898 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4899 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4900 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); }
4901 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4902 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4903 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4904 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4905 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4906 }
4907
4908 /**
4909 * A default visitor for symbols. All visitor methods except
4910 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4911 * subclasses must provide an implementation of visitSymbol and can
4912 * override other methods as needed.
4913 *
4914 * @param <R> the return type of the operation implemented by this
4915 * visitor; use Void if no return type is needed.
4916 * @param <S> the type of the second argument (the first being the
4917 * symbol itself) of the operation implemented by this visitor; use
4918 * Void if a second argument is not needed.
4919 */
4920 public abstract static class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4921 public final R visit(Symbol s, S arg) { return s.accept(this, arg); }
4922 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4923 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4924 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4925 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4926 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4927 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4928 }
4929
4930 /**
4931 * A <em>simple</em> visitor for types. This visitor is simple as
4932 * captured wildcards, for-all types (generic methods), and
4933 * undetermined type variables (part of inference) are hidden.
4934 * Captured wildcards are hidden by treating them as type
4935 * variables and the rest are hidden by visiting their qtypes.
4936 *
4937 * @param <R> the return type of the operation implemented by this
4938 * visitor; use Void if no return type is needed.
4939 * @param <S> the type of the second argument (the first being the
4940 * type itself) of the operation implemented by this visitor; use
4941 * Void if a second argument is not needed.
4942 */
4943 public abstract static class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4944 @Override
4945 public R visitCapturedType(CapturedType t, S s) {
4946 return visitTypeVar(t, s);
4947 }
4948 @Override
4949 public R visitForAll(ForAll t, S s) {
4950 return visit(t.qtype, s);
4951 }
4952 @Override
4953 public R visitUndetVar(UndetVar t, S s) {
4954 return visit(t.qtype, s);
4955 }
4956 }
4957
4958 /**
4959 * A plain relation on types. That is a 2-ary function on the
4960 * form Type × Type → Boolean.
4961 * <!-- In plain text: Type x Type -> Boolean -->
4962 */
4963 public abstract static class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4964
4965 /**
4966 * A convenience visitor for implementing operations that only
4967 * require one argument (the type itself), that is, unary
4968 * operations.
4969 *
4970 * @param <R> the return type of the operation implemented by this
4971 * visitor; use Void if no return type is needed.
4972 */
4973 public abstract static class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4974 public final R visit(Type t) { return t.accept(this, null); }
4975 }
4976
4977 /**
4978 * A visitor for implementing a mapping from types to types. The
4979 * default behavior of this class is to implement the identity
4980 * mapping (mapping a type to itself). This can be overridden in
4981 * subclasses.
4982 *
4983 * @param <S> the type of the second argument (the first being the
4984 * type itself) of this mapping; use Void if a second argument is
4985 * not needed.
4986 */
4987 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4988 public final Type visit(Type t) { return t.accept(this, null); }
4989 public Type visitType(Type t, S s) { return t; }
4990 }
4991
4992 /**
4993 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}.
4994 * This class implements the functional interface {@code Function}, that allows it to be used
4995 * fluently in stream-like processing.
4996 */
4997 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> {
4998 @Override
4999 public Type apply(Type type) { return visit(type); }
5000
5001 List<Type> visit(List<Type> ts, S s) {
5002 return ts.map(t -> visit(t, s));
5003 }
5004
5005 @Override
5006 public Type visitCapturedType(CapturedType t, S s) {
5007 return visitTypeVar(t, s);
5008 }
5009 }
5010 // </editor-fold>
5011
5012
5013 // <editor-fold defaultstate="collapsed" desc="Annotation support">
5014
5015 public RetentionPolicy getRetention(Attribute.Compound a) {
5016 return getRetention(a.type.tsym);
5017 }
5018
5019 public RetentionPolicy getRetention(TypeSymbol sym) {
5020 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
5021 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
5022 if (c != null) {
5023 Attribute value = c.member(names.value);
5024 if (value != null && value instanceof Attribute.Enum attributeEnum) {
5025 Name levelName = attributeEnum.value.name;
5026 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
5027 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
5028 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
5029 else ;// /* fail soft */ throw new AssertionError(levelName);
5030 }
5031 }
5032 return vis;
5033 }
5034 // </editor-fold>
5035
5036 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
5037
5038 public abstract static class SignatureGenerator {
5039
5040 public static class InvalidSignatureException extends RuntimeException {
5041 private static final long serialVersionUID = 0;
5042
5043 private final transient Type type;
5044
5045 InvalidSignatureException(Type type) {
5046 this.type = type;
5047 }
5048
5049 public Type type() {
5050 return type;
5051 }
5052
5053 @Override
5054 public Throwable fillInStackTrace() {
5055 // This is an internal exception; the stack trace is irrelevant.
5056 return this;
5057 }
5058 }
5059
5060 private final Types types;
5061
5062 protected abstract void append(char ch);
5063 protected abstract void append(byte[] ba);
5064 protected abstract void append(Name name);
5065 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
5066
5067 protected SignatureGenerator(Types types) {
5068 this.types = types;
5069 }
5070
5071 protected void reportIllegalSignature(Type t) {
5072 throw new InvalidSignatureException(t);
5073 }
5074
5075 /**
5076 * Assemble signature of given type in string buffer.
5077 */
5078 public void assembleSig(Type type) {
5079 switch (type.getTag()) {
5080 case BYTE:
5081 append('B');
5082 break;
5083 case SHORT:
5084 append('S');
5085 break;
5086 case CHAR:
5087 append('C');
5088 break;
5089 case INT:
5090 append('I');
5091 break;
5092 case LONG:
5093 append('J');
5094 break;
5095 case FLOAT:
5096 append('F');
5097 break;
5098 case DOUBLE:
5099 append('D');
5100 break;
5101 case BOOLEAN:
5102 append('Z');
5103 break;
5104 case VOID:
5105 append('V');
5106 break;
5107 case CLASS:
5108 if (type.isCompound()) {
5109 reportIllegalSignature(type);
5110 }
5111 append('L');
5112 assembleClassSig(type);
5113 append(';');
5114 break;
5115 case ARRAY:
5116 ArrayType at = (ArrayType) type;
5117 append('[');
5118 assembleSig(at.elemtype);
5119 break;
5120 case METHOD:
5121 MethodType mt = (MethodType) type;
5122 append('(');
5123 assembleSig(mt.argtypes);
5124 append(')');
5125 assembleSig(mt.restype);
5126 if (hasTypeVar(mt.thrown)) {
5127 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
5128 append('^');
5129 assembleSig(l.head);
5130 }
5131 }
5132 break;
5133 case WILDCARD: {
5134 Type.WildcardType ta = (Type.WildcardType) type;
5135 switch (ta.kind) {
5136 case SUPER:
5137 append('-');
5138 assembleSig(ta.type);
5139 break;
5140 case EXTENDS:
5141 append('+');
5142 assembleSig(ta.type);
5143 break;
5144 case UNBOUND:
5145 append('*');
5146 break;
5147 default:
5148 throw new AssertionError(ta.kind);
5149 }
5150 break;
5151 }
5152 case TYPEVAR:
5153 if (((TypeVar)type).isCaptured()) {
5154 reportIllegalSignature(type);
5155 }
5156 append('T');
5157 append(type.tsym.name);
5158 append(';');
5159 break;
5160 case FORALL:
5161 Type.ForAll ft = (Type.ForAll) type;
5162 assembleParamsSig(ft.tvars);
5163 assembleSig(ft.qtype);
5164 break;
5165 default:
5166 throw new AssertionError("typeSig " + type.getTag());
5167 }
5168 }
5169
5170 public boolean hasTypeVar(List<Type> l) {
5171 while (l.nonEmpty()) {
5172 if (l.head.hasTag(TypeTag.TYPEVAR)) {
5173 return true;
5174 }
5175 l = l.tail;
5176 }
5177 return false;
5178 }
5179
5180 public void assembleClassSig(Type type) {
5181 ClassType ct = (ClassType) type;
5182 ClassSymbol c = (ClassSymbol) ct.tsym;
5183 classReference(c);
5184 Type outer = ct.getEnclosingType();
5185 if (outer.allparams().nonEmpty()) {
5186 boolean rawOuter =
5187 c.owner.kind == MTH || // either a local class
5188 c.name == types.names.empty; // or anonymous
5189 assembleClassSig(rawOuter
5190 ? types.erasure(outer)
5191 : outer);
5192 append(rawOuter ? '$' : '.');
5193 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
5194 append(rawOuter
5195 ? c.flatname.subName(c.owner.enclClass().flatname.length() + 1)
5196 : c.name);
5197 } else {
5198 append(externalize(c.flatname));
5199 }
5200 if (ct.getTypeArguments().nonEmpty()) {
5201 append('<');
5202 assembleSig(ct.getTypeArguments());
5203 append('>');
5204 }
5205 }
5206
5207 public void assembleParamsSig(List<Type> typarams) {
5208 append('<');
5209 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
5210 Type.TypeVar tvar = (Type.TypeVar) ts.head;
5211 append(tvar.tsym.name);
5212 List<Type> bounds = types.getBounds(tvar);
5213 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
5214 append(':');
5215 }
5216 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
5217 append(':');
5218 assembleSig(l.head);
5219 }
5220 }
5221 append('>');
5222 }
5223
5224 public void assembleSig(List<Type> types) {
5225 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
5226 assembleSig(ts.head);
5227 }
5228 }
5229 }
5230
5231 public Type constantType(LoadableConstant c) {
5232 switch (c.poolTag()) {
5233 case ClassFile.CONSTANT_Class:
5234 return syms.classType;
5235 case ClassFile.CONSTANT_String:
5236 return syms.stringType;
5237 case ClassFile.CONSTANT_Integer:
5238 return syms.intType;
5239 case ClassFile.CONSTANT_Float:
5240 return syms.floatType;
5241 case ClassFile.CONSTANT_Long:
5242 return syms.longType;
5243 case ClassFile.CONSTANT_Double:
5244 return syms.doubleType;
5245 case ClassFile.CONSTANT_MethodHandle:
5246 return syms.methodHandleType;
5247 case ClassFile.CONSTANT_MethodType:
5248 return syms.methodTypeType;
5249 case ClassFile.CONSTANT_Dynamic:
5250 return ((DynamicVarSymbol)c).type;
5251 default:
5252 throw new AssertionError("Not a loadable constant: " + c.poolTag());
5253 }
5254 }
5255 // </editor-fold>
5256
5257 public void newRound() {
5258 descCache._map.clear();
5259 isDerivedRawCache.clear();
5260 implCache._map.clear();
5261 membersCache._map.clear();
5262 closureCache.clear();
5263 }
5264 }