1 /*
2 * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.tools.javac.code;
27
28 import java.lang.ref.SoftReference;
29 import java.util.HashSet;
30 import java.util.HashMap;
31 import java.util.Locale;
32 import java.util.Map;
33 import java.util.Optional;
34 import java.util.Set;
35 import java.util.WeakHashMap;
36 import java.util.function.BiPredicate;
37 import java.util.function.Function;
38 import java.util.function.Predicate;
39 import java.util.stream.Collector;
40
41 import javax.tools.JavaFileObject;
42
43 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
44 import com.sun.tools.javac.code.Lint.LintCategory;
45 import com.sun.tools.javac.code.Source.Feature;
46 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
47 import com.sun.tools.javac.code.TypeMetadata.Entry.Kind;
48 import com.sun.tools.javac.comp.AttrContext;
49 import com.sun.tools.javac.comp.Check;
50 import com.sun.tools.javac.comp.Enter;
51 import com.sun.tools.javac.comp.Env;
52 import com.sun.tools.javac.comp.LambdaToMethod;
53 import com.sun.tools.javac.jvm.ClassFile;
54 import com.sun.tools.javac.util.*;
55
56 import static com.sun.tools.javac.code.BoundKind.*;
57 import static com.sun.tools.javac.code.Flags.*;
58 import static com.sun.tools.javac.code.Kinds.Kind.*;
59 import static com.sun.tools.javac.code.Scope.*;
60 import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
61 import static com.sun.tools.javac.code.Symbol.*;
62 import static com.sun.tools.javac.code.Type.*;
63 import static com.sun.tools.javac.code.TypeTag.*;
64 import static com.sun.tools.javac.jvm.ClassFile.externalize;
65 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
66
67 /**
68 * Utility class containing various operations on types.
69 *
70 * <p>Unless other names are more illustrative, the following naming
71 * conventions should be observed in this file:
72 *
73 * <dl>
74 * <dt>t</dt>
75 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
76 * <dt>s</dt>
77 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
78 * <dt>ts</dt>
79 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
80 * <dt>ss</dt>
81 * <dd>A second list of types should be named ss.</dd>
82 * </dl>
83 *
84 * <p><b>This is NOT part of any supported API.
85 * If you write code that depends on this, you do so at your own risk.
86 * This code and its internal interfaces are subject to change or
87 * deletion without notice.</b>
88 */
89 public class Types {
90 protected static final Context.Key<Types> typesKey = new Context.Key<>();
91
92 final Symtab syms;
93 final JavacMessages messages;
94 final Names names;
95 final boolean allowDefaultMethods;
96 final boolean mapCapturesToBounds;
97 final Check chk;
98 final Enter enter;
99 JCDiagnostic.Factory diags;
100 List<Warner> warnStack = List.nil();
101 final Name capturedName;
102
103 public final Warner noWarnings;
104
105 // <editor-fold defaultstate="collapsed" desc="Instantiating">
106 public static Types instance(Context context) {
107 Types instance = context.get(typesKey);
108 if (instance == null)
109 instance = new Types(context);
110 return instance;
111 }
112
113 protected Types(Context context) {
114 context.put(typesKey, this);
115 syms = Symtab.instance(context);
116 names = Names.instance(context);
117 Source source = Source.instance(context);
118 allowDefaultMethods = Feature.DEFAULT_METHODS.allowedInSource(source);
119 mapCapturesToBounds = Feature.MAP_CAPTURES_TO_BOUNDS.allowedInSource(source);
120 chk = Check.instance(context);
121 enter = Enter.instance(context);
122 capturedName = names.fromString("<captured wildcard>");
123 messages = JavacMessages.instance(context);
124 diags = JCDiagnostic.Factory.instance(context);
125 noWarnings = new Warner(null);
126 }
127 // </editor-fold>
128
129 // <editor-fold defaultstate="collapsed" desc="bounds">
130 /**
131 * Get a wildcard's upper bound, returning non-wildcards unchanged.
132 * @param t a type argument, either a wildcard or a type
133 */
134 public Type wildUpperBound(Type t) {
135 if (t.hasTag(WILDCARD)) {
136 WildcardType w = (WildcardType) t;
137 if (w.isSuperBound())
138 return w.bound == null ? syms.objectType : w.bound.getUpperBound();
139 else
140 return wildUpperBound(w.type);
141 }
142 else return t;
143 }
144
145 /**
146 * Get a capture variable's upper bound, returning other types unchanged.
147 * @param t a type
148 */
149 public Type cvarUpperBound(Type t) {
150 if (t.hasTag(TYPEVAR)) {
151 TypeVar v = (TypeVar) t;
152 return v.isCaptured() ? cvarUpperBound(v.getUpperBound()) : v;
153 }
154 else return t;
155 }
156
157 /**
158 * Get a wildcard's lower bound, returning non-wildcards unchanged.
159 * @param t a type argument, either a wildcard or a type
160 */
161 public Type wildLowerBound(Type t) {
162 if (t.hasTag(WILDCARD)) {
163 WildcardType w = (WildcardType) t;
164 return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type);
165 }
166 else return t;
167 }
168
169 /**
170 * Get a capture variable's lower bound, returning other types unchanged.
171 * @param t a type
172 */
173 public Type cvarLowerBound(Type t) {
174 if (t.hasTag(TYPEVAR) && ((TypeVar) t).isCaptured()) {
175 return cvarLowerBound(t.getLowerBound());
176 }
177 else return t;
178 }
179
180 /**
181 * Recursively skip type-variables until a class/array type is found; capture conversion is then
182 * (optionally) applied to the resulting type. This is useful for i.e. computing a site that is
183 * suitable for a method lookup.
184 */
185 public Type skipTypeVars(Type site, boolean capture) {
186 while (site.hasTag(TYPEVAR)) {
187 site = site.getUpperBound();
188 }
189 return capture ? capture(site) : site;
190 }
191 // </editor-fold>
192
193 // <editor-fold defaultstate="collapsed" desc="projections">
194
195 /**
196 * A projection kind. See {@link TypeProjection}
197 */
198 enum ProjectionKind {
199 UPWARDS() {
200 @Override
201 ProjectionKind complement() {
202 return DOWNWARDS;
203 }
204 },
205 DOWNWARDS() {
206 @Override
207 ProjectionKind complement() {
208 return UPWARDS;
209 }
210 };
211
212 abstract ProjectionKind complement();
213 }
214
215 /**
216 * This visitor performs upwards and downwards projections on types.
217 *
218 * A projection is defined as a function that takes a type T, a set of type variables V and that
219 * produces another type S.
220 *
221 * An upwards projection maps a type T into a type S such that (i) T has no variables in V,
222 * and (ii) S is an upper bound of T.
223 *
224 * A downwards projection maps a type T into a type S such that (i) T has no variables in V,
225 * and (ii) S is a lower bound of T.
226 *
227 * Note that projections are only allowed to touch variables in V. Therefore, it is possible for
228 * a projection to leave its input type unchanged if it does not contain any variables in V.
229 *
230 * Moreover, note that while an upwards projection is always defined (every type as an upper bound),
231 * a downwards projection is not always defined.
232 *
233 * Examples:
234 *
235 * {@code upwards(List<#CAP1>, [#CAP1]) = List<? extends String>, where #CAP1 <: String }
236 * {@code downwards(List<#CAP2>, [#CAP2]) = List<? super String>, where #CAP2 :> String }
237 * {@code upwards(List<#CAP1>, [#CAP2]) = List<#CAP1> }
238 * {@code downwards(List<#CAP1>, [#CAP1]) = not defined }
239 */
240 class TypeProjection extends TypeMapping<ProjectionKind> {
241
242 List<Type> vars;
243 Set<Type> seen = new HashSet<>();
244
245 public TypeProjection(List<Type> vars) {
246 this.vars = vars;
247 }
248
249 @Override
250 public Type visitClassType(ClassType t, ProjectionKind pkind) {
251 if (t.isCompound()) {
252 List<Type> components = directSupertypes(t);
253 List<Type> components1 = components.map(c -> c.map(this, pkind));
254 if (components == components1) return t;
255 else return makeIntersectionType(components1);
256 } else {
257 Type outer = t.getEnclosingType();
258 Type outer1 = visit(outer, pkind);
259 List<Type> typarams = t.getTypeArguments();
260 List<Type> formals = t.tsym.type.getTypeArguments();
261 ListBuffer<Type> typarams1 = new ListBuffer<>();
262 boolean changed = false;
263 for (Type actual : typarams) {
264 Type t2 = mapTypeArgument(t, formals.head.getUpperBound(), actual, pkind);
265 if (t2.hasTag(BOT)) {
266 //not defined
267 return syms.botType;
268 }
269 typarams1.add(t2);
270 changed |= actual != t2;
271 formals = formals.tail;
272 }
273 if (outer1 == outer && !changed) return t;
274 else return new ClassType(outer1, typarams1.toList(), t.tsym, t.getMetadata()) {
275 @Override
276 protected boolean needsStripping() {
277 return true;
278 }
279 };
280 }
281 }
282
283 @Override
284 public Type visitArrayType(ArrayType t, ProjectionKind s) {
285 Type elemtype = t.elemtype;
286 Type elemtype1 = visit(elemtype, s);
287 if (elemtype1 == elemtype) {
288 return t;
289 } else if (elemtype1.hasTag(BOT)) {
290 //undefined
291 return syms.botType;
292 } else {
293 return new ArrayType(elemtype1, t.tsym, t.metadata) {
294 @Override
295 protected boolean needsStripping() {
296 return true;
297 }
298 };
299 }
300 }
301
302 @Override
303 public Type visitTypeVar(TypeVar t, ProjectionKind pkind) {
304 if (vars.contains(t)) {
305 if (seen.add(t)) {
306 try {
307 final Type bound;
308 switch (pkind) {
309 case UPWARDS:
310 bound = t.getUpperBound();
311 break;
312 case DOWNWARDS:
313 bound = (t.getLowerBound() == null) ?
314 syms.botType :
315 t.getLowerBound();
316 break;
317 default:
318 Assert.error();
319 return null;
320 }
321 return bound.map(this, pkind);
322 } finally {
323 seen.remove(t);
324 }
325 } else {
326 //cycle
327 return pkind == ProjectionKind.UPWARDS ?
328 syms.objectType : syms.botType;
329 }
330 } else {
331 return t;
332 }
333 }
334
335 private Type mapTypeArgument(Type site, Type declaredBound, Type t, ProjectionKind pkind) {
336 return t.containsAny(vars) ?
337 t.map(new TypeArgumentProjection(site, declaredBound), pkind) :
338 t;
339 }
340
341 class TypeArgumentProjection extends TypeMapping<ProjectionKind> {
342
343 Type site;
344 Type declaredBound;
345
346 TypeArgumentProjection(Type site, Type declaredBound) {
347 this.site = site;
348 this.declaredBound = declaredBound;
349 }
350
351 @Override
352 public Type visitType(Type t, ProjectionKind pkind) {
353 //type argument is some type containing restricted vars
354 if (pkind == ProjectionKind.DOWNWARDS) {
355 //not defined
356 return syms.botType;
357 }
358 Type upper = t.map(TypeProjection.this, ProjectionKind.UPWARDS);
359 Type lower = t.map(TypeProjection.this, ProjectionKind.DOWNWARDS);
360 List<Type> formals = site.tsym.type.getTypeArguments();
361 BoundKind bk;
362 Type bound;
363 if (!isSameType(upper, syms.objectType) &&
364 (declaredBound.containsAny(formals) ||
365 !isSubtype(declaredBound, upper))) {
366 bound = upper;
367 bk = EXTENDS;
368 } else if (!lower.hasTag(BOT)) {
369 bound = lower;
370 bk = SUPER;
371 } else {
372 bound = syms.objectType;
373 bk = UNBOUND;
374 }
375 return makeWildcard(bound, bk);
376 }
377
378 @Override
379 public Type visitWildcardType(WildcardType wt, ProjectionKind pkind) {
380 //type argument is some wildcard whose bound contains restricted vars
381 Type bound = syms.botType;
382 BoundKind bk = wt.kind;
383 switch (wt.kind) {
384 case EXTENDS:
385 bound = wt.type.map(TypeProjection.this, pkind);
386 if (bound.hasTag(BOT)) {
387 return syms.botType;
388 }
389 break;
390 case SUPER:
391 bound = wt.type.map(TypeProjection.this, pkind.complement());
392 if (bound.hasTag(BOT)) {
393 bound = syms.objectType;
394 bk = UNBOUND;
395 }
396 break;
397 }
398 return makeWildcard(bound, bk);
399 }
400
401 private Type makeWildcard(Type bound, BoundKind bk) {
402 return new WildcardType(bound, bk, syms.boundClass) {
403 @Override
404 protected boolean needsStripping() {
405 return true;
406 }
407 };
408 }
409 }
410 }
411
412 /**
413 * Computes an upward projection of given type, and vars. See {@link TypeProjection}.
414 *
415 * @param t the type to be projected
416 * @param vars the set of type variables to be mapped
417 * @return the type obtained as result of the projection
418 */
419 public Type upward(Type t, List<Type> vars) {
420 return t.map(new TypeProjection(vars), ProjectionKind.UPWARDS);
421 }
422
423 /**
424 * Computes the set of captured variables mentioned in a given type. See {@link CaptureScanner}.
425 * This routine is typically used to computed the input set of variables to be used during
426 * an upwards projection (see {@link Types#upward(Type, List)}).
427 *
428 * @param t the type where occurrences of captured variables have to be found
429 * @return the set of captured variables found in t
430 */
431 public List<Type> captures(Type t) {
432 CaptureScanner cs = new CaptureScanner();
433 Set<Type> captures = new HashSet<>();
434 cs.visit(t, captures);
435 return List.from(captures);
436 }
437
438 /**
439 * This visitor scans a type recursively looking for occurrences of captured type variables.
440 */
441 class CaptureScanner extends SimpleVisitor<Void, Set<Type>> {
442
443 @Override
444 public Void visitType(Type t, Set<Type> types) {
445 return null;
446 }
447
448 @Override
449 public Void visitClassType(ClassType t, Set<Type> seen) {
450 if (t.isCompound()) {
451 directSupertypes(t).forEach(s -> visit(s, seen));
452 } else {
453 t.allparams().forEach(ta -> visit(ta, seen));
454 }
455 return null;
456 }
457
458 @Override
459 public Void visitArrayType(ArrayType t, Set<Type> seen) {
460 return visit(t.elemtype, seen);
461 }
462
463 @Override
464 public Void visitWildcardType(WildcardType t, Set<Type> seen) {
465 visit(t.type, seen);
466 return null;
467 }
468
469 @Override
470 public Void visitTypeVar(TypeVar t, Set<Type> seen) {
471 if ((t.tsym.flags() & Flags.SYNTHETIC) != 0 && seen.add(t)) {
472 visit(t.getUpperBound(), seen);
473 }
474 return null;
475 }
476
477 @Override
478 public Void visitCapturedType(CapturedType t, Set<Type> seen) {
479 if (seen.add(t)) {
480 visit(t.getUpperBound(), seen);
481 visit(t.getLowerBound(), seen);
482 }
483 return null;
484 }
485 }
486
487 // </editor-fold>
488
489 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
490 /**
491 * Checks that all the arguments to a class are unbounded
492 * wildcards or something else that doesn't make any restrictions
493 * on the arguments. If a class isUnbounded, a raw super- or
494 * subclass can be cast to it without a warning.
495 * @param t a type
496 * @return true iff the given type is unbounded or raw
497 */
498 public boolean isUnbounded(Type t) {
499 return isUnbounded.visit(t);
500 }
501 // where
502 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
503
504 public Boolean visitType(Type t, Void ignored) {
505 return true;
506 }
507
508 @Override
509 public Boolean visitClassType(ClassType t, Void ignored) {
510 List<Type> parms = t.tsym.type.allparams();
511 List<Type> args = t.allparams();
512 while (parms.nonEmpty()) {
513 WildcardType unb = new WildcardType(syms.objectType,
514 BoundKind.UNBOUND,
515 syms.boundClass,
516 (TypeVar)parms.head);
517 if (!containsType(args.head, unb))
518 return false;
519 parms = parms.tail;
520 args = args.tail;
521 }
522 return true;
523 }
524 };
525 // </editor-fold>
526
527 // <editor-fold defaultstate="collapsed" desc="asSub">
528 /**
529 * Return the least specific subtype of t that starts with symbol
530 * sym. If none exists, return null. The least specific subtype
531 * is determined as follows:
532 *
533 * <p>If there is exactly one parameterized instance of sym that is a
534 * subtype of t, that parameterized instance is returned.<br>
535 * Otherwise, if the plain type or raw type `sym' is a subtype of
536 * type t, the type `sym' itself is returned. Otherwise, null is
537 * returned.
538 */
539 public Type asSub(Type t, Symbol sym) {
540 return asSub.visit(t, sym);
541 }
542 // where
543 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
544
545 public Type visitType(Type t, Symbol sym) {
546 return null;
547 }
548
549 @Override
550 public Type visitClassType(ClassType t, Symbol sym) {
551 if (t.tsym == sym)
552 return t;
553 Type base = asSuper(sym.type, t.tsym);
554 if (base == null)
555 return null;
556 ListBuffer<Type> from = new ListBuffer<>();
557 ListBuffer<Type> to = new ListBuffer<>();
558 try {
559 adapt(base, t, from, to);
560 } catch (AdaptFailure ex) {
561 return null;
562 }
563 Type res = subst(sym.type, from.toList(), to.toList());
564 if (!isSubtype(res, t))
565 return null;
566 ListBuffer<Type> openVars = new ListBuffer<>();
567 for (List<Type> l = sym.type.allparams();
568 l.nonEmpty(); l = l.tail)
569 if (res.contains(l.head) && !t.contains(l.head))
570 openVars.append(l.head);
571 if (openVars.nonEmpty()) {
572 if (t.isRaw()) {
573 // The subtype of a raw type is raw
574 res = erasure(res);
575 } else {
576 // Unbound type arguments default to ?
577 List<Type> opens = openVars.toList();
578 ListBuffer<Type> qs = new ListBuffer<>();
579 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
580 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND,
581 syms.boundClass, (TypeVar) iter.head));
582 }
583 res = subst(res, opens, qs.toList());
584 }
585 }
586 return res;
587 }
588
589 @Override
590 public Type visitErrorType(ErrorType t, Symbol sym) {
591 return t;
592 }
593 };
594 // </editor-fold>
595
596 // <editor-fold defaultstate="collapsed" desc="isConvertible">
597 /**
598 * Is t a subtype of or convertible via boxing/unboxing
599 * conversion to s?
600 */
601 public boolean isConvertible(Type t, Type s, Warner warn) {
602 if (t.hasTag(ERROR)) {
603 return true;
604 }
605 boolean tPrimitive = t.isPrimitive();
606 boolean sPrimitive = s.isPrimitive();
607 if (tPrimitive == sPrimitive) {
608 return isSubtypeUnchecked(t, s, warn);
609 }
610 boolean tUndet = t.hasTag(UNDETVAR);
611 boolean sUndet = s.hasTag(UNDETVAR);
612
613 if (tUndet || sUndet) {
614 return tUndet ?
615 isSubtype(t, boxedTypeOrType(s)) :
616 isSubtype(boxedTypeOrType(t), s);
617 }
618
619 return tPrimitive
620 ? isSubtype(boxedClass(t).type, s)
621 : isSubtype(unboxedType(t), s);
622 }
623
624 /**
625 * Is t a subtype of or convertible via boxing/unboxing
626 * conversions to s?
627 */
628 public boolean isConvertible(Type t, Type s) {
629 return isConvertible(t, s, noWarnings);
630 }
631 // </editor-fold>
632
633 // <editor-fold defaultstate="collapsed" desc="findSam">
634
635 /**
636 * Exception used to report a function descriptor lookup failure. The exception
637 * wraps a diagnostic that can be used to generate more details error
638 * messages.
639 */
640 public static class FunctionDescriptorLookupError extends RuntimeException {
641 private static final long serialVersionUID = 0;
642
643 transient JCDiagnostic diagnostic;
644
645 FunctionDescriptorLookupError() {
646 this.diagnostic = null;
647 }
648
649 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
650 this.diagnostic = diag;
651 return this;
652 }
653
654 public JCDiagnostic getDiagnostic() {
655 return diagnostic;
656 }
657 }
658
659 /**
660 * A cache that keeps track of function descriptors associated with given
661 * functional interfaces.
662 */
663 class DescriptorCache {
664
665 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<>();
666
667 class FunctionDescriptor {
668 Symbol descSym;
669
670 FunctionDescriptor(Symbol descSym) {
671 this.descSym = descSym;
672 }
673
674 public Symbol getSymbol() {
675 return descSym;
676 }
677
678 public Type getType(Type site) {
679 site = removeWildcards(site);
680 if (site.isIntersection()) {
681 IntersectionClassType ict = (IntersectionClassType)site;
682 for (Type component : ict.getExplicitComponents()) {
683 if (!chk.checkValidGenericType(component)) {
684 //if the inferred functional interface type is not well-formed,
685 //or if it's not a subtype of the original target, issue an error
686 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
687 }
688 }
689 } else {
690 if (!chk.checkValidGenericType(site)) {
691 //if the inferred functional interface type is not well-formed,
692 //or if it's not a subtype of the original target, issue an error
693 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
694 }
695 }
696 return memberType(site, descSym);
697 }
698 }
699
700 class Entry {
701 final FunctionDescriptor cachedDescRes;
702 final int prevMark;
703
704 public Entry(FunctionDescriptor cachedDescRes,
705 int prevMark) {
706 this.cachedDescRes = cachedDescRes;
707 this.prevMark = prevMark;
708 }
709
710 boolean matches(int mark) {
711 return this.prevMark == mark;
712 }
713 }
714
715 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
716 Entry e = _map.get(origin);
717 CompoundScope members = membersClosure(origin.type, false);
718 if (e == null ||
719 !e.matches(members.getMark())) {
720 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
721 _map.put(origin, new Entry(descRes, members.getMark()));
722 return descRes;
723 }
724 else {
725 return e.cachedDescRes;
726 }
727 }
728
729 /**
730 * Compute the function descriptor associated with a given functional interface
731 */
732 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin,
733 CompoundScope membersCache) throws FunctionDescriptorLookupError {
734 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0 || origin.isSealed()) {
735 //t must be an interface
736 throw failure("not.a.functional.intf", origin);
737 }
738
739 final ListBuffer<Symbol> abstracts = new ListBuffer<>();
740 for (Symbol sym : membersCache.getSymbols(new DescriptorFilter(origin))) {
741 Type mtype = memberType(origin.type, sym);
742 if (abstracts.isEmpty()) {
743 abstracts.append(sym);
744 } else if ((sym.name == abstracts.first().name &&
745 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
746 if (!abstracts.stream().filter(msym -> msym.owner.isSubClass(sym.enclClass(), Types.this))
747 .map(msym -> memberType(origin.type, msym))
748 .anyMatch(abstractMType -> isSubSignature(abstractMType, mtype))) {
749 abstracts.append(sym);
750 }
751 } else {
752 //the target method(s) should be the only abstract members of t
753 throw failure("not.a.functional.intf.1", origin,
754 diags.fragment(Fragments.IncompatibleAbstracts(Kinds.kindName(origin), origin)));
755 }
756 }
757 if (abstracts.isEmpty()) {
758 //t must define a suitable non-generic method
759 throw failure("not.a.functional.intf.1", origin,
760 diags.fragment(Fragments.NoAbstracts(Kinds.kindName(origin), origin)));
761 } else if (abstracts.size() == 1) {
762 return new FunctionDescriptor(abstracts.first());
763 } else { // size > 1
764 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
765 if (descRes == null) {
766 //we can get here if the functional interface is ill-formed
767 ListBuffer<JCDiagnostic> descriptors = new ListBuffer<>();
768 for (Symbol desc : abstracts) {
769 String key = desc.type.getThrownTypes().nonEmpty() ?
770 "descriptor.throws" : "descriptor";
771 descriptors.append(diags.fragment(key, desc.name,
772 desc.type.getParameterTypes(),
773 desc.type.getReturnType(),
774 desc.type.getThrownTypes()));
775 }
776 JCDiagnostic msg =
777 diags.fragment(Fragments.IncompatibleDescsInFunctionalIntf(Kinds.kindName(origin),
778 origin));
779 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
780 new JCDiagnostic.MultilineDiagnostic(msg, descriptors.toList());
781 throw failure(incompatibleDescriptors);
782 }
783 return descRes;
784 }
785 }
786
787 /**
788 * Compute a synthetic type for the target descriptor given a list
789 * of override-equivalent methods in the functional interface type.
790 * The resulting method type is a method type that is override-equivalent
791 * and return-type substitutable with each method in the original list.
792 */
793 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
794 return mergeAbstracts(methodSyms, origin.type, false)
795 .map(bestSoFar -> new FunctionDescriptor(bestSoFar.baseSymbol()) {
796 @Override
797 public Type getType(Type origin) {
798 Type mt = memberType(origin, getSymbol());
799 return createMethodTypeWithThrown(mt, bestSoFar.type.getThrownTypes());
800 }
801 }).orElse(null);
802 }
803
804 FunctionDescriptorLookupError failure(String msg, Object... args) {
805 return failure(diags.fragment(msg, args));
806 }
807
808 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
809 return new FunctionDescriptorLookupError().setMessage(diag);
810 }
811 }
812
813 private DescriptorCache descCache = new DescriptorCache();
814
815 /**
816 * Find the method descriptor associated to this class symbol - if the
817 * symbol 'origin' is not a functional interface, an exception is thrown.
818 */
819 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
820 return descCache.get(origin).getSymbol();
821 }
822
823 /**
824 * Find the type of the method descriptor associated to this class symbol -
825 * if the symbol 'origin' is not a functional interface, an exception is thrown.
826 */
827 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
828 return descCache.get(origin.tsym).getType(origin);
829 }
830
831 /**
832 * Is given type a functional interface?
833 */
834 public boolean isFunctionalInterface(TypeSymbol tsym) {
835 try {
836 findDescriptorSymbol(tsym);
837 return true;
838 } catch (FunctionDescriptorLookupError ex) {
839 return false;
840 }
841 }
842
843 public boolean isFunctionalInterface(Type site) {
844 try {
845 findDescriptorType(site);
846 return true;
847 } catch (FunctionDescriptorLookupError ex) {
848 return false;
849 }
850 }
851
852 public Type removeWildcards(Type site) {
853 if (site.getTypeArguments().stream().anyMatch(t -> t.hasTag(WILDCARD))) {
854 //compute non-wildcard parameterization - JLS 9.9
855 List<Type> actuals = site.getTypeArguments();
856 List<Type> formals = site.tsym.type.getTypeArguments();
857 ListBuffer<Type> targs = new ListBuffer<>();
858 for (Type formal : formals) {
859 Type actual = actuals.head;
860 Type bound = formal.getUpperBound();
861 if (actuals.head.hasTag(WILDCARD)) {
862 WildcardType wt = (WildcardType)actual;
863 //check that bound does not contain other formals
864 if (bound.containsAny(formals)) {
865 targs.add(wt.type);
866 } else {
867 //compute new type-argument based on declared bound and wildcard bound
868 switch (wt.kind) {
869 case UNBOUND:
870 targs.add(bound);
871 break;
872 case EXTENDS:
873 targs.add(glb(bound, wt.type));
874 break;
875 case SUPER:
876 targs.add(wt.type);
877 break;
878 default:
879 Assert.error("Cannot get here!");
880 }
881 }
882 } else {
883 //not a wildcard - the new type argument remains unchanged
884 targs.add(actual);
885 }
886 actuals = actuals.tail;
887 }
888 return subst(site.tsym.type, formals, targs.toList());
889 } else {
890 return site;
891 }
892 }
893
894 /**
895 * Create a symbol for a class that implements a given functional interface
896 * and overrides its functional descriptor. This routine is used for two
897 * main purposes: (i) checking well-formedness of a functional interface;
898 * (ii) perform functional interface bridge calculation.
899 */
900 public ClassSymbol makeFunctionalInterfaceClass(Env<AttrContext> env, Name name, Type target, long cflags) {
901 if (target == null || target == syms.unknownType) {
902 return null;
903 }
904 Symbol descSym = findDescriptorSymbol(target.tsym);
905 Type descType = findDescriptorType(target);
906 ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass());
907 csym.completer = Completer.NULL_COMPLETER;
908 csym.members_field = WriteableScope.create(csym);
909 MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym);
910 csym.members_field.enter(instDescSym);
911 Type.ClassType ctype = new Type.ClassType(Type.noType, List.nil(), csym);
912 ctype.supertype_field = syms.objectType;
913 ctype.interfaces_field = target.isIntersection() ?
914 directSupertypes(target) :
915 List.of(target);
916 csym.type = ctype;
917 csym.sourcefile = ((ClassSymbol)csym.owner).sourcefile;
918 return csym;
919 }
920
921 /**
922 * Find the minimal set of methods that are overridden by the functional
923 * descriptor in 'origin'. All returned methods are assumed to have different
924 * erased signatures.
925 */
926 public List<Symbol> functionalInterfaceBridges(TypeSymbol origin) {
927 Assert.check(isFunctionalInterface(origin));
928 Symbol descSym = findDescriptorSymbol(origin);
929 CompoundScope members = membersClosure(origin.type, false);
930 ListBuffer<Symbol> overridden = new ListBuffer<>();
931 outer: for (Symbol m2 : members.getSymbolsByName(descSym.name, bridgeFilter)) {
932 if (m2 == descSym) continue;
933 else if (descSym.overrides(m2, origin, Types.this, false)) {
934 for (Symbol m3 : overridden) {
935 if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) ||
936 (m3.overrides(m2, origin, Types.this, false) &&
937 (pendingBridges((ClassSymbol)origin, m3.enclClass()) ||
938 (((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) {
939 continue outer;
940 }
941 }
942 overridden.add(m2);
943 }
944 }
945 return overridden.toList();
946 }
947 //where
948 // Use anonymous class instead of lambda expression intentionally,
949 // because the variable `names` has modifier: final.
950 private Predicate<Symbol> bridgeFilter = new Predicate<Symbol>() {
951 public boolean test(Symbol t) {
952 return t.kind == MTH &&
953 t.name != names.init &&
954 t.name != names.clinit &&
955 (t.flags() & SYNTHETIC) == 0;
956 }
957 };
958
959 private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) {
960 //a symbol will be completed from a classfile if (a) symbol has
961 //an associated file object with CLASS kind and (b) the symbol has
962 //not been entered
963 if (origin.classfile != null &&
964 origin.classfile.getKind() == JavaFileObject.Kind.CLASS &&
965 enter.getEnv(origin) == null) {
966 return false;
967 }
968 if (origin == s) {
969 return true;
970 }
971 for (Type t : interfaces(origin.type)) {
972 if (pendingBridges((ClassSymbol)t.tsym, s)) {
973 return true;
974 }
975 }
976 return false;
977 }
978 // </editor-fold>
979
980 /**
981 * Scope filter used to skip methods that should be ignored (such as methods
982 * overridden by j.l.Object) during function interface conversion interface check
983 */
984 class DescriptorFilter implements Predicate<Symbol> {
985
986 TypeSymbol origin;
987
988 DescriptorFilter(TypeSymbol origin) {
989 this.origin = origin;
990 }
991
992 @Override
993 public boolean test(Symbol sym) {
994 return sym.kind == MTH &&
995 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
996 !overridesObjectMethod(origin, sym) &&
997 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
998 }
999 }
1000
1001 // <editor-fold defaultstate="collapsed" desc="isSubtype">
1002 /**
1003 * Is t an unchecked subtype of s?
1004 */
1005 public boolean isSubtypeUnchecked(Type t, Type s) {
1006 return isSubtypeUnchecked(t, s, noWarnings);
1007 }
1008 /**
1009 * Is t an unchecked subtype of s?
1010 */
1011 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
1012 boolean result = isSubtypeUncheckedInternal(t, s, true, warn);
1013 if (result) {
1014 checkUnsafeVarargsConversion(t, s, warn);
1015 }
1016 return result;
1017 }
1018 //where
1019 private boolean isSubtypeUncheckedInternal(Type t, Type s, boolean capture, Warner warn) {
1020 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
1021 if (((ArrayType)t).elemtype.isPrimitive()) {
1022 return isSameType(elemtype(t), elemtype(s));
1023 } else {
1024 return isSubtypeUncheckedInternal(elemtype(t), elemtype(s), false, warn);
1025 }
1026 } else if (isSubtype(t, s, capture)) {
1027 return true;
1028 } else if (t.hasTag(TYPEVAR)) {
1029 return isSubtypeUncheckedInternal(t.getUpperBound(), s, false, warn);
1030 } else if (!s.isRaw()) {
1031 Type t2 = asSuper(t, s.tsym);
1032 if (t2 != null && t2.isRaw()) {
1033 if (isReifiable(s)) {
1034 warn.silentWarn(LintCategory.UNCHECKED);
1035 } else {
1036 warn.warn(LintCategory.UNCHECKED);
1037 }
1038 return true;
1039 }
1040 }
1041 return false;
1042 }
1043
1044 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
1045 if (!t.hasTag(ARRAY) || isReifiable(t)) {
1046 return;
1047 }
1048 ArrayType from = (ArrayType)t;
1049 boolean shouldWarn = false;
1050 switch (s.getTag()) {
1051 case ARRAY:
1052 ArrayType to = (ArrayType)s;
1053 shouldWarn = from.isVarargs() &&
1054 !to.isVarargs() &&
1055 !isReifiable(from);
1056 break;
1057 case CLASS:
1058 shouldWarn = from.isVarargs();
1059 break;
1060 }
1061 if (shouldWarn) {
1062 warn.warn(LintCategory.VARARGS);
1063 }
1064 }
1065
1066 /**
1067 * Is t a subtype of s?<br>
1068 * (not defined for Method and ForAll types)
1069 */
1070 public final boolean isSubtype(Type t, Type s) {
1071 return isSubtype(t, s, true);
1072 }
1073 public final boolean isSubtypeNoCapture(Type t, Type s) {
1074 return isSubtype(t, s, false);
1075 }
1076 public boolean isSubtype(Type t, Type s, boolean capture) {
1077 if (t.equalsIgnoreMetadata(s))
1078 return true;
1079 if (s.isPartial())
1080 return isSuperType(s, t);
1081
1082 if (s.isCompound()) {
1083 for (Type s2 : interfaces(s).prepend(supertype(s))) {
1084 if (!isSubtype(t, s2, capture))
1085 return false;
1086 }
1087 return true;
1088 }
1089
1090 // Generally, if 's' is a lower-bounded type variable, recur on lower bound; but
1091 // for inference variables and intersections, we need to keep 's'
1092 // (see JLS 4.10.2 for intersections and 18.2.3 for inference vars)
1093 if (!t.hasTag(UNDETVAR) && !t.isCompound()) {
1094 // TODO: JDK-8039198, bounds checking sometimes passes in a wildcard as s
1095 Type lower = cvarLowerBound(wildLowerBound(s));
1096 if (s != lower && !lower.hasTag(BOT))
1097 return isSubtype(capture ? capture(t) : t, lower, false);
1098 }
1099
1100 return isSubtype.visit(capture ? capture(t) : t, s);
1101 }
1102 // where
1103 private TypeRelation isSubtype = new TypeRelation()
1104 {
1105 @Override
1106 public Boolean visitType(Type t, Type s) {
1107 switch (t.getTag()) {
1108 case BYTE:
1109 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
1110 case CHAR:
1111 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
1112 case SHORT: case INT: case LONG:
1113 case FLOAT: case DOUBLE:
1114 return t.getTag().isSubRangeOf(s.getTag());
1115 case BOOLEAN: case VOID:
1116 return t.hasTag(s.getTag());
1117 case TYPEVAR:
1118 return isSubtypeNoCapture(t.getUpperBound(), s);
1119 case BOT:
1120 return
1121 s.hasTag(BOT) || s.hasTag(CLASS) ||
1122 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
1123 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
1124 case NONE:
1125 return false;
1126 default:
1127 throw new AssertionError("isSubtype " + t.getTag());
1128 }
1129 }
1130
1131 private Set<TypePair> cache = new HashSet<>();
1132
1133 private boolean containsTypeRecursive(Type t, Type s) {
1134 TypePair pair = new TypePair(t, s);
1135 if (cache.add(pair)) {
1136 try {
1137 return containsType(t.getTypeArguments(),
1138 s.getTypeArguments());
1139 } finally {
1140 cache.remove(pair);
1141 }
1142 } else {
1143 return containsType(t.getTypeArguments(),
1144 rewriteSupers(s).getTypeArguments());
1145 }
1146 }
1147
1148 private Type rewriteSupers(Type t) {
1149 if (!t.isParameterized())
1150 return t;
1151 ListBuffer<Type> from = new ListBuffer<>();
1152 ListBuffer<Type> to = new ListBuffer<>();
1153 adaptSelf(t, from, to);
1154 if (from.isEmpty())
1155 return t;
1156 ListBuffer<Type> rewrite = new ListBuffer<>();
1157 boolean changed = false;
1158 for (Type orig : to.toList()) {
1159 Type s = rewriteSupers(orig);
1160 if (s.isSuperBound() && !s.isExtendsBound()) {
1161 s = new WildcardType(syms.objectType,
1162 BoundKind.UNBOUND,
1163 syms.boundClass,
1164 s.getMetadata());
1165 changed = true;
1166 } else if (s != orig) {
1167 s = new WildcardType(wildUpperBound(s),
1168 BoundKind.EXTENDS,
1169 syms.boundClass,
1170 s.getMetadata());
1171 changed = true;
1172 }
1173 rewrite.append(s);
1174 }
1175 if (changed)
1176 return subst(t.tsym.type, from.toList(), rewrite.toList());
1177 else
1178 return t;
1179 }
1180
1181 @Override
1182 public Boolean visitClassType(ClassType t, Type s) {
1183 Type sup = asSuper(t, s.tsym);
1184 if (sup == null) return false;
1185 // If t is an intersection, sup might not be a class type
1186 if (!sup.hasTag(CLASS)) return isSubtypeNoCapture(sup, s);
1187 return sup.tsym == s.tsym
1188 // Check type variable containment
1189 && (!s.isParameterized() || containsTypeRecursive(s, sup))
1190 && isSubtypeNoCapture(sup.getEnclosingType(),
1191 s.getEnclosingType());
1192 }
1193
1194 @Override
1195 public Boolean visitArrayType(ArrayType t, Type s) {
1196 if (s.hasTag(ARRAY)) {
1197 if (t.elemtype.isPrimitive())
1198 return isSameType(t.elemtype, elemtype(s));
1199 else
1200 return isSubtypeNoCapture(t.elemtype, elemtype(s));
1201 }
1202
1203 if (s.hasTag(CLASS)) {
1204 Name sname = s.tsym.getQualifiedName();
1205 return sname == names.java_lang_Object
1206 || sname == names.java_lang_Cloneable
1207 || sname == names.java_io_Serializable;
1208 }
1209
1210 return false;
1211 }
1212
1213 @Override
1214 public Boolean visitUndetVar(UndetVar t, Type s) {
1215 //todo: test against origin needed? or replace with substitution?
1216 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
1217 return true;
1218 } else if (s.hasTag(BOT)) {
1219 //if 's' is 'null' there's no instantiated type U for which
1220 //U <: s (but 'null' itself, which is not a valid type)
1221 return false;
1222 }
1223
1224 t.addBound(InferenceBound.UPPER, s, Types.this);
1225 return true;
1226 }
1227
1228 @Override
1229 public Boolean visitErrorType(ErrorType t, Type s) {
1230 return true;
1231 }
1232 };
1233
1234 /**
1235 * Is t a subtype of every type in given list `ts'?<br>
1236 * (not defined for Method and ForAll types)<br>
1237 * Allows unchecked conversions.
1238 */
1239 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
1240 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
1241 if (!isSubtypeUnchecked(t, l.head, warn))
1242 return false;
1243 return true;
1244 }
1245
1246 /**
1247 * Are corresponding elements of ts subtypes of ss? If lists are
1248 * of different length, return false.
1249 */
1250 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
1251 while (ts.tail != null && ss.tail != null
1252 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1253 isSubtype(ts.head, ss.head)) {
1254 ts = ts.tail;
1255 ss = ss.tail;
1256 }
1257 return ts.tail == null && ss.tail == null;
1258 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1259 }
1260
1261 /**
1262 * Are corresponding elements of ts subtypes of ss, allowing
1263 * unchecked conversions? If lists are of different length,
1264 * return false.
1265 **/
1266 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
1267 while (ts.tail != null && ss.tail != null
1268 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1269 isSubtypeUnchecked(ts.head, ss.head, warn)) {
1270 ts = ts.tail;
1271 ss = ss.tail;
1272 }
1273 return ts.tail == null && ss.tail == null;
1274 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1275 }
1276 // </editor-fold>
1277
1278 // <editor-fold defaultstate="collapsed" desc="isSuperType">
1279 /**
1280 * Is t a supertype of s?
1281 */
1282 public boolean isSuperType(Type t, Type s) {
1283 switch (t.getTag()) {
1284 case ERROR:
1285 return true;
1286 case UNDETVAR: {
1287 UndetVar undet = (UndetVar)t;
1288 if (t == s ||
1289 undet.qtype == s ||
1290 s.hasTag(ERROR) ||
1291 s.hasTag(BOT)) {
1292 return true;
1293 }
1294 undet.addBound(InferenceBound.LOWER, s, this);
1295 return true;
1296 }
1297 default:
1298 return isSubtype(s, t);
1299 }
1300 }
1301 // </editor-fold>
1302
1303 // <editor-fold defaultstate="collapsed" desc="isSameType">
1304 /**
1305 * Are corresponding elements of the lists the same type? If
1306 * lists are of different length, return false.
1307 */
1308 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
1309 while (ts.tail != null && ss.tail != null
1310 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1311 isSameType(ts.head, ss.head)) {
1312 ts = ts.tail;
1313 ss = ss.tail;
1314 }
1315 return ts.tail == null && ss.tail == null;
1316 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1317 }
1318
1319 /**
1320 * A polymorphic signature method (JLS 15.12.3) is a method that
1321 * (i) is declared in the java.lang.invoke.MethodHandle/VarHandle classes;
1322 * (ii) takes a single variable arity parameter;
1323 * (iii) whose declared type is Object[];
1324 * (iv) has any return type, Object signifying a polymorphic return type; and
1325 * (v) is native.
1326 */
1327 public boolean isSignaturePolymorphic(MethodSymbol msym) {
1328 List<Type> argtypes = msym.type.getParameterTypes();
1329 return (msym.flags_field & NATIVE) != 0 &&
1330 (msym.owner == syms.methodHandleType.tsym || msym.owner == syms.varHandleType.tsym) &&
1331 argtypes.length() == 1 &&
1332 argtypes.head.hasTag(TypeTag.ARRAY) &&
1333 ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym;
1334 }
1335
1336 /**
1337 * Is t the same type as s?
1338 */
1339 public boolean isSameType(Type t, Type s) {
1340 return isSameTypeVisitor.visit(t, s);
1341 }
1342 // where
1343
1344 /**
1345 * Type-equality relation - type variables are considered
1346 * equals if they share the same object identity.
1347 */
1348 TypeRelation isSameTypeVisitor = new TypeRelation() {
1349
1350 public Boolean visitType(Type t, Type s) {
1351 if (t.equalsIgnoreMetadata(s))
1352 return true;
1353
1354 if (s.isPartial())
1355 return visit(s, t);
1356
1357 switch (t.getTag()) {
1358 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1359 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
1360 return t.hasTag(s.getTag());
1361 case TYPEVAR: {
1362 if (s.hasTag(TYPEVAR)) {
1363 //type-substitution does not preserve type-var types
1364 //check that type var symbols and bounds are indeed the same
1365 return t == s;
1366 }
1367 else {
1368 //special case for s == ? super X, where upper(s) = u
1369 //check that u == t, where u has been set by Type.withTypeVar
1370 return s.isSuperBound() &&
1371 !s.isExtendsBound() &&
1372 visit(t, wildUpperBound(s));
1373 }
1374 }
1375 default:
1376 throw new AssertionError("isSameType " + t.getTag());
1377 }
1378 }
1379
1380 @Override
1381 public Boolean visitWildcardType(WildcardType t, Type s) {
1382 if (!s.hasTag(WILDCARD)) {
1383 return false;
1384 } else {
1385 WildcardType t2 = (WildcardType)s;
1386 return (t.kind == t2.kind || (t.isExtendsBound() && s.isExtendsBound())) &&
1387 isSameType(t.type, t2.type);
1388 }
1389 }
1390
1391 @Override
1392 public Boolean visitClassType(ClassType t, Type s) {
1393 if (t == s)
1394 return true;
1395
1396 if (s.isPartial())
1397 return visit(s, t);
1398
1399 if (s.isSuperBound() && !s.isExtendsBound())
1400 return visit(t, wildUpperBound(s)) && visit(t, wildLowerBound(s));
1401
1402 if (t.isCompound() && s.isCompound()) {
1403 if (!visit(supertype(t), supertype(s)))
1404 return false;
1405
1406 Map<Symbol,Type> tMap = new HashMap<>();
1407 for (Type ti : interfaces(t)) {
1408 if (tMap.containsKey(ti)) {
1409 throw new AssertionError("Malformed intersection");
1410 }
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 visit(elemtype(t), elemtype(s));
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() != TypeMetadata.EMPTY) {
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.cloneWithMetadata(s.getMetadata().without(Kind.ANNOTATIONS));
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.getMetadata().without(Kind.ANNOTATIONS));
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 super 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="sub signature / override equivalence">
2784 /**
2785 * Returns true iff the first signature is a <em>sub
2786 * signature</em> 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 sub signature of s.
2794 */
2795 public boolean isSubSignature(Type t, Type s) {
2796 return isSubSignature(t, s, true);
2797 }
2798
2799 public boolean isSubSignature(Type t, Type s, boolean strict) {
2800 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2801 }
2802
2803 /**
2804 * Returns true iff these signatures are related by <em>override
2805 * equivalence</em>. This is the natural extension of
2806 * isSubSignature to an equivalence relation.
2807 *
2808 * @jls 8.4.2 Method Signature
2809 * @see #isSubSignature(Type t, Type s)
2810 * @param t a signature (possible raw, could be subjected to
2811 * erasure).
2812 * @param s a signature (possible raw, could be subjected to
2813 * erasure).
2814 * @return true if either argument is a sub signature of the other.
2815 */
2816 public boolean overrideEquivalent(Type t, Type s) {
2817 return hasSameArgs(t, s) ||
2818 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2819 }
2820
2821 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2822 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) {
2823 if (msym.overrides(sym, origin, Types.this, true)) {
2824 return true;
2825 }
2826 }
2827 return false;
2828 }
2829
2830 /**
2831 * This enum defines the strategy for implementing most specific return type check
2832 * during the most specific and functional interface checks.
2833 */
2834 public enum MostSpecificReturnCheck {
2835 /**
2836 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling
2837 * method type variables (if either method is generic) and (ii) subtyping should be replaced
2838 * by type-equivalence for primitives. This is essentially an inlined version of
2839 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been
2840 * replaced with a strict subtyping check.
2841 */
2842 BASIC() {
2843 @Override
2844 public boolean test(Type mt1, Type mt2, Types types) {
2845 List<Type> tvars = mt1.getTypeArguments();
2846 List<Type> svars = mt2.getTypeArguments();
2847 Type t = mt1.getReturnType();
2848 Type s = types.subst(mt2.getReturnType(), svars, tvars);
2849 return types.isSameType(t, s) ||
2850 !t.isPrimitive() &&
2851 !s.isPrimitive() &&
2852 types.isSubtype(t, s);
2853 }
2854 },
2855 /**
2856 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2.
2857 */
2858 RTS() {
2859 @Override
2860 public boolean test(Type mt1, Type mt2, Types types) {
2861 return types.returnTypeSubstitutable(mt1, mt2);
2862 }
2863 };
2864
2865 public abstract boolean test(Type mt1, Type mt2, Types types);
2866 }
2867
2868 /**
2869 * Merge multiple abstract methods. The preferred method is a method that is a subsignature
2870 * of all the other signatures and whose return type is more specific {@see MostSpecificReturnCheck}.
2871 * The resulting preferred method has a thrown clause that is the intersection of the merged
2872 * methods' clauses.
2873 */
2874 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) {
2875 //first check for preconditions
2876 boolean shouldErase = false;
2877 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes();
2878 for (Symbol s : ambiguousInOrder) {
2879 if ((s.flags() & ABSTRACT) == 0 ||
2880 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) {
2881 return Optional.empty();
2882 } else if (s.type.hasTag(FORALL)) {
2883 shouldErase = true;
2884 }
2885 }
2886 //then merge abstracts
2887 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) {
2888 outer: for (Symbol s : ambiguousInOrder) {
2889 Type mt = memberType(site, s);
2890 List<Type> allThrown = mt.getThrownTypes();
2891 for (Symbol s2 : ambiguousInOrder) {
2892 if (s != s2) {
2893 Type mt2 = memberType(site, s2);
2894 if (!isSubSignature(mt, mt2) ||
2895 !mostSpecificReturnCheck.test(mt, mt2, this)) {
2896 //ambiguity cannot be resolved
2897 continue outer;
2898 } else {
2899 List<Type> thrownTypes2 = mt2.getThrownTypes();
2900 if (!mt.hasTag(FORALL) && shouldErase) {
2901 thrownTypes2 = erasure(thrownTypes2);
2902 } else if (mt.hasTag(FORALL)) {
2903 //subsignature implies that if most specific is generic, then all other
2904 //methods are too
2905 Assert.check(mt2.hasTag(FORALL));
2906 // if both are generic methods, adjust thrown types ahead of intersection computation
2907 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments());
2908 }
2909 allThrown = chk.intersect(allThrown, thrownTypes2);
2910 }
2911 }
2912 }
2913 return (allThrown == mt.getThrownTypes()) ?
2914 Optional.of(s) :
2915 Optional.of(new MethodSymbol(
2916 s.flags(),
2917 s.name,
2918 createMethodTypeWithThrown(s.type, allThrown),
2919 s.owner) {
2920 @Override
2921 public Symbol baseSymbol() {
2922 return s;
2923 }
2924 });
2925 }
2926 }
2927 return Optional.empty();
2928 }
2929
2930 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2931 class ImplementationCache {
2932
2933 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>();
2934
2935 class Entry {
2936 final MethodSymbol cachedImpl;
2937 final Predicate<Symbol> implFilter;
2938 final boolean checkResult;
2939 final int prevMark;
2940
2941 public Entry(MethodSymbol cachedImpl,
2942 Predicate<Symbol> scopeFilter,
2943 boolean checkResult,
2944 int prevMark) {
2945 this.cachedImpl = cachedImpl;
2946 this.implFilter = scopeFilter;
2947 this.checkResult = checkResult;
2948 this.prevMark = prevMark;
2949 }
2950
2951 boolean matches(Predicate<Symbol> scopeFilter, boolean checkResult, int mark) {
2952 return this.implFilter == scopeFilter &&
2953 this.checkResult == checkResult &&
2954 this.prevMark == mark;
2955 }
2956 }
2957
2958 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2959 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2960 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2961 if (cache == null) {
2962 cache = new HashMap<>();
2963 _map.put(ms, new SoftReference<>(cache));
2964 }
2965 Entry e = cache.get(origin);
2966 CompoundScope members = membersClosure(origin.type, true);
2967 if (e == null ||
2968 !e.matches(implFilter, checkResult, members.getMark())) {
2969 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2970 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2971 return impl;
2972 }
2973 else {
2974 return e.cachedImpl;
2975 }
2976 }
2977
2978 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2979 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
2980 t = skipTypeVars(t, false);
2981 TypeSymbol c = t.tsym;
2982 Symbol bestSoFar = null;
2983 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) {
2984 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) {
2985 bestSoFar = sym;
2986 if ((sym.flags() & ABSTRACT) == 0) {
2987 //if concrete impl is found, exit immediately
2988 break;
2989 }
2990 }
2991 }
2992 if (bestSoFar != null) {
2993 //return either the (only) concrete implementation or the first abstract one
2994 return (MethodSymbol)bestSoFar;
2995 }
2996 }
2997 return null;
2998 }
2999 }
3000
3001 private ImplementationCache implCache = new ImplementationCache();
3002
3003 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
3004 return implCache.get(ms, origin, checkResult, implFilter);
3005 }
3006 // </editor-fold>
3007
3008 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
3009 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> {
3010
3011 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>();
3012
3013 Set<TypeSymbol> seenTypes = new HashSet<>();
3014
3015 class MembersScope extends CompoundScope {
3016
3017 CompoundScope scope;
3018
3019 public MembersScope(CompoundScope scope) {
3020 super(scope.owner);
3021 this.scope = scope;
3022 }
3023
3024 Predicate<Symbol> combine(Predicate<Symbol> sf) {
3025 return s -> !s.owner.isInterface() && (sf == null || sf.test(s));
3026 }
3027
3028 @Override
3029 public Iterable<Symbol> getSymbols(Predicate<Symbol> sf, LookupKind lookupKind) {
3030 return scope.getSymbols(combine(sf), lookupKind);
3031 }
3032
3033 @Override
3034 public Iterable<Symbol> getSymbolsByName(Name name, Predicate<Symbol> sf, LookupKind lookupKind) {
3035 return scope.getSymbolsByName(name, combine(sf), lookupKind);
3036 }
3037
3038 @Override
3039 public int getMark() {
3040 return scope.getMark();
3041 }
3042 }
3043
3044 CompoundScope nilScope;
3045
3046 /** members closure visitor methods **/
3047
3048 public CompoundScope visitType(Type t, Void _unused) {
3049 if (nilScope == null) {
3050 nilScope = new CompoundScope(syms.noSymbol);
3051 }
3052 return nilScope;
3053 }
3054
3055 @Override
3056 public CompoundScope visitClassType(ClassType t, Void _unused) {
3057 if (!seenTypes.add(t.tsym)) {
3058 //this is possible when an interface is implemented in multiple
3059 //superclasses, or when a class hierarchy is circular - in such
3060 //cases we don't need to recurse (empty scope is returned)
3061 return new CompoundScope(t.tsym);
3062 }
3063 try {
3064 seenTypes.add(t.tsym);
3065 ClassSymbol csym = (ClassSymbol)t.tsym;
3066 CompoundScope membersClosure = _map.get(csym);
3067 if (membersClosure == null) {
3068 membersClosure = new CompoundScope(csym);
3069 for (Type i : interfaces(t)) {
3070 membersClosure.prependSubScope(visit(i, null));
3071 }
3072 membersClosure.prependSubScope(visit(supertype(t), null));
3073 membersClosure.prependSubScope(csym.members());
3074 _map.put(csym, membersClosure);
3075 }
3076 return membersClosure;
3077 }
3078 finally {
3079 seenTypes.remove(t.tsym);
3080 }
3081 }
3082
3083 @Override
3084 public CompoundScope visitTypeVar(TypeVar t, Void _unused) {
3085 return visit(t.getUpperBound(), null);
3086 }
3087 }
3088
3089 private MembersClosureCache membersCache = new MembersClosureCache();
3090
3091 public CompoundScope membersClosure(Type site, boolean skipInterface) {
3092 CompoundScope cs = membersCache.visit(site, null);
3093 Assert.checkNonNull(cs, () -> "type " + site);
3094 return skipInterface ? membersCache.new MembersScope(cs) : cs;
3095 }
3096 // </editor-fold>
3097
3098
3099 /** Return first abstract member of class `sym'.
3100 */
3101 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) {
3102 try {
3103 return firstUnimplementedAbstractImpl(sym, sym);
3104 } catch (CompletionFailure ex) {
3105 chk.completionError(enter.getEnv(sym).tree.pos(), ex);
3106 return null;
3107 }
3108 }
3109 //where:
3110 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) {
3111 MethodSymbol undef = null;
3112 // Do not bother to search in classes that are not abstract,
3113 // since they cannot have abstract members.
3114 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
3115 Scope s = c.members();
3116 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
3117 if (sym.kind == MTH &&
3118 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
3119 MethodSymbol absmeth = (MethodSymbol)sym;
3120 MethodSymbol implmeth = absmeth.implementation(impl, this, true);
3121 if (implmeth == null || implmeth == absmeth) {
3122 //look for default implementations
3123 if (allowDefaultMethods) {
3124 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head;
3125 if (prov != null && prov.overrides(absmeth, impl, this, true)) {
3126 implmeth = prov;
3127 }
3128 }
3129 }
3130 if (implmeth == null || implmeth == absmeth) {
3131 undef = absmeth;
3132 break;
3133 }
3134 }
3135 }
3136 if (undef == null) {
3137 Type st = supertype(c.type);
3138 if (st.hasTag(CLASS))
3139 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym);
3140 }
3141 for (List<Type> l = interfaces(c.type);
3142 undef == null && l.nonEmpty();
3143 l = l.tail) {
3144 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym);
3145 }
3146 }
3147 return undef;
3148 }
3149
3150 public class CandidatesCache {
3151 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>();
3152
3153 class Entry {
3154 Type site;
3155 MethodSymbol msym;
3156
3157 Entry(Type site, MethodSymbol msym) {
3158 this.site = site;
3159 this.msym = msym;
3160 }
3161
3162 @Override
3163 public boolean equals(Object obj) {
3164 return (obj instanceof Entry entry)
3165 && entry.msym == msym
3166 && isSameType(site, entry.site);
3167 }
3168
3169 @Override
3170 public int hashCode() {
3171 return Types.this.hashCode(site) & ~msym.hashCode();
3172 }
3173 }
3174
3175 public List<MethodSymbol> get(Entry e) {
3176 return cache.get(e);
3177 }
3178
3179 public void put(Entry e, List<MethodSymbol> msymbols) {
3180 cache.put(e, msymbols);
3181 }
3182 }
3183
3184 public CandidatesCache candidatesCache = new CandidatesCache();
3185
3186 //where
3187 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
3188 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms);
3189 List<MethodSymbol> candidates = candidatesCache.get(e);
3190 if (candidates == null) {
3191 Predicate<Symbol> filter = new MethodFilter(ms, site);
3192 List<MethodSymbol> candidates2 = List.nil();
3193 for (Symbol s : membersClosure(site, false).getSymbols(filter)) {
3194 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
3195 return List.of((MethodSymbol)s);
3196 } else if (!candidates2.contains(s)) {
3197 candidates2 = candidates2.prepend((MethodSymbol)s);
3198 }
3199 }
3200 candidates = prune(candidates2);
3201 candidatesCache.put(e, candidates);
3202 }
3203 return candidates;
3204 }
3205
3206 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
3207 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>();
3208 for (MethodSymbol m1 : methods) {
3209 boolean isMin_m1 = true;
3210 for (MethodSymbol m2 : methods) {
3211 if (m1 == m2) continue;
3212 if (m2.owner != m1.owner &&
3213 asSuper(m2.owner.type, m1.owner) != null) {
3214 isMin_m1 = false;
3215 break;
3216 }
3217 }
3218 if (isMin_m1)
3219 methodsMin.append(m1);
3220 }
3221 return methodsMin.toList();
3222 }
3223 // where
3224 private class MethodFilter implements Predicate<Symbol> {
3225
3226 Symbol msym;
3227 Type site;
3228
3229 MethodFilter(Symbol msym, Type site) {
3230 this.msym = msym;
3231 this.site = site;
3232 }
3233
3234 @Override
3235 public boolean test(Symbol s) {
3236 return s.kind == MTH &&
3237 s.name == msym.name &&
3238 (s.flags() & SYNTHETIC) == 0 &&
3239 s.isInheritedIn(site.tsym, Types.this) &&
3240 overrideEquivalent(memberType(site, s), memberType(site, msym));
3241 }
3242 }
3243 // </editor-fold>
3244
3245 /**
3246 * Does t have the same arguments as s? It is assumed that both
3247 * types are (possibly polymorphic) method types. Monomorphic
3248 * method types "have the same arguments", if their argument lists
3249 * are equal. Polymorphic method types "have the same arguments",
3250 * if they have the same arguments after renaming all type
3251 * variables of one to corresponding type variables in the other,
3252 * where correspondence is by position in the type parameter list.
3253 */
3254 public boolean hasSameArgs(Type t, Type s) {
3255 return hasSameArgs(t, s, true);
3256 }
3257
3258 public boolean hasSameArgs(Type t, Type s, boolean strict) {
3259 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
3260 }
3261
3262 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
3263 return hasSameArgs.visit(t, s);
3264 }
3265 // where
3266 private class HasSameArgs extends TypeRelation {
3267
3268 boolean strict;
3269
3270 public HasSameArgs(boolean strict) {
3271 this.strict = strict;
3272 }
3273
3274 public Boolean visitType(Type t, Type s) {
3275 throw new AssertionError();
3276 }
3277
3278 @Override
3279 public Boolean visitMethodType(MethodType t, Type s) {
3280 return s.hasTag(METHOD)
3281 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
3282 }
3283
3284 @Override
3285 public Boolean visitForAll(ForAll t, Type s) {
3286 if (!s.hasTag(FORALL))
3287 return strict ? false : visitMethodType(t.asMethodType(), s);
3288
3289 ForAll forAll = (ForAll)s;
3290 return hasSameBounds(t, forAll)
3291 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
3292 }
3293
3294 @Override
3295 public Boolean visitErrorType(ErrorType t, Type s) {
3296 return false;
3297 }
3298 }
3299
3300 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
3301 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
3302
3303 // </editor-fold>
3304
3305 // <editor-fold defaultstate="collapsed" desc="subst">
3306 public List<Type> subst(List<Type> ts,
3307 List<Type> from,
3308 List<Type> to) {
3309 return ts.map(new Subst(from, to));
3310 }
3311
3312 /**
3313 * Substitute all occurrences of a type in `from' with the
3314 * corresponding type in `to' in 't'. Match lists `from' and `to'
3315 * from the right: If lists have different length, discard leading
3316 * elements of the longer list.
3317 */
3318 public Type subst(Type t, List<Type> from, List<Type> to) {
3319 return t.map(new Subst(from, to));
3320 }
3321
3322 private class Subst extends StructuralTypeMapping<Void> {
3323 List<Type> from;
3324 List<Type> to;
3325
3326 public Subst(List<Type> from, List<Type> to) {
3327 int fromLength = from.length();
3328 int toLength = to.length();
3329 while (fromLength > toLength) {
3330 fromLength--;
3331 from = from.tail;
3332 }
3333 while (fromLength < toLength) {
3334 toLength--;
3335 to = to.tail;
3336 }
3337 this.from = from;
3338 this.to = to;
3339 }
3340
3341 @Override
3342 public Type visitTypeVar(TypeVar t, Void ignored) {
3343 for (List<Type> from = this.from, to = this.to;
3344 from.nonEmpty();
3345 from = from.tail, to = to.tail) {
3346 if (t.equalsIgnoreMetadata(from.head)) {
3347 return to.head.withTypeVar(t);
3348 }
3349 }
3350 return t;
3351 }
3352
3353 @Override
3354 public Type visitClassType(ClassType t, Void ignored) {
3355 if (!t.isCompound()) {
3356 return super.visitClassType(t, ignored);
3357 } else {
3358 Type st = visit(supertype(t));
3359 List<Type> is = visit(interfaces(t), ignored);
3360 if (st == supertype(t) && is == interfaces(t))
3361 return t;
3362 else
3363 return makeIntersectionType(is.prepend(st));
3364 }
3365 }
3366
3367 @Override
3368 public Type visitWildcardType(WildcardType t, Void ignored) {
3369 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored);
3370 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) {
3371 t2.type = wildUpperBound(t2.type);
3372 }
3373 return t2;
3374 }
3375
3376 @Override
3377 public Type visitForAll(ForAll t, Void ignored) {
3378 if (Type.containsAny(to, t.tvars)) {
3379 //perform alpha-renaming of free-variables in 't'
3380 //if 'to' types contain variables that are free in 't'
3381 List<Type> freevars = newInstances(t.tvars);
3382 t = new ForAll(freevars,
3383 Types.this.subst(t.qtype, t.tvars, freevars));
3384 }
3385 List<Type> tvars1 = substBounds(t.tvars, from, to);
3386 Type qtype1 = visit(t.qtype);
3387 if (tvars1 == t.tvars && qtype1 == t.qtype) {
3388 return t;
3389 } else if (tvars1 == t.tvars) {
3390 return new ForAll(tvars1, qtype1) {
3391 @Override
3392 public boolean needsStripping() {
3393 return true;
3394 }
3395 };
3396 } else {
3397 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) {
3398 @Override
3399 public boolean needsStripping() {
3400 return true;
3401 }
3402 };
3403 }
3404 }
3405 }
3406
3407 public List<Type> substBounds(List<Type> tvars,
3408 List<Type> from,
3409 List<Type> to) {
3410 if (tvars.isEmpty())
3411 return tvars;
3412 ListBuffer<Type> newBoundsBuf = new ListBuffer<>();
3413 boolean changed = false;
3414 // calculate new bounds
3415 for (Type t : tvars) {
3416 TypeVar tv = (TypeVar) t;
3417 Type bound = subst(tv.getUpperBound(), from, to);
3418 if (bound != tv.getUpperBound())
3419 changed = true;
3420 newBoundsBuf.append(bound);
3421 }
3422 if (!changed)
3423 return tvars;
3424 ListBuffer<Type> newTvars = new ListBuffer<>();
3425 // create new type variables without bounds
3426 for (Type t : tvars) {
3427 newTvars.append(new TypeVar(t.tsym, null, syms.botType,
3428 t.getMetadata()));
3429 }
3430 // the new bounds should use the new type variables in place
3431 // of the old
3432 List<Type> newBounds = newBoundsBuf.toList();
3433 from = tvars;
3434 to = newTvars.toList();
3435 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
3436 newBounds.head = subst(newBounds.head, from, to);
3437 }
3438 newBounds = newBoundsBuf.toList();
3439 // set the bounds of new type variables to the new bounds
3440 for (Type t : newTvars.toList()) {
3441 TypeVar tv = (TypeVar) t;
3442 tv.setUpperBound( newBounds.head );
3443 newBounds = newBounds.tail;
3444 }
3445 return newTvars.toList();
3446 }
3447
3448 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
3449 Type bound1 = subst(t.getUpperBound(), from, to);
3450 if (bound1 == t.getUpperBound())
3451 return t;
3452 else {
3453 // create new type variable without bounds
3454 TypeVar tv = new TypeVar(t.tsym, null, syms.botType,
3455 t.getMetadata());
3456 // the new bound should use the new type variable in place
3457 // of the old
3458 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) );
3459 return tv;
3460 }
3461 }
3462 // </editor-fold>
3463
3464 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
3465 /**
3466 * Does t have the same bounds for quantified variables as s?
3467 */
3468 public boolean hasSameBounds(ForAll t, ForAll s) {
3469 List<Type> l1 = t.tvars;
3470 List<Type> l2 = s.tvars;
3471 while (l1.nonEmpty() && l2.nonEmpty() &&
3472 isSameType(l1.head.getUpperBound(),
3473 subst(l2.head.getUpperBound(),
3474 s.tvars,
3475 t.tvars))) {
3476 l1 = l1.tail;
3477 l2 = l2.tail;
3478 }
3479 return l1.isEmpty() && l2.isEmpty();
3480 }
3481 // </editor-fold>
3482
3483 // <editor-fold defaultstate="collapsed" desc="newInstances">
3484 /** Create new vector of type variables from list of variables
3485 * changing all recursive bounds from old to new list.
3486 */
3487 public List<Type> newInstances(List<Type> tvars) {
3488 List<Type> tvars1 = tvars.map(newInstanceFun);
3489 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
3490 TypeVar tv = (TypeVar) l.head;
3491 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) );
3492 }
3493 return tvars1;
3494 }
3495 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() {
3496 @Override
3497 public TypeVar visitTypeVar(TypeVar t, Void _unused) {
3498 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata());
3499 }
3500 };
3501 // </editor-fold>
3502
3503 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
3504 return original.accept(methodWithParameters, newParams);
3505 }
3506 // where
3507 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
3508 public Type visitType(Type t, List<Type> newParams) {
3509 throw new IllegalArgumentException("Not a method type: " + t);
3510 }
3511 public Type visitMethodType(MethodType t, List<Type> newParams) {
3512 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
3513 }
3514 public Type visitForAll(ForAll t, List<Type> newParams) {
3515 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
3516 }
3517 };
3518
3519 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
3520 return original.accept(methodWithThrown, newThrown);
3521 }
3522 // where
3523 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
3524 public Type visitType(Type t, List<Type> newThrown) {
3525 throw new IllegalArgumentException("Not a method type: " + t);
3526 }
3527 public Type visitMethodType(MethodType t, List<Type> newThrown) {
3528 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
3529 }
3530 public Type visitForAll(ForAll t, List<Type> newThrown) {
3531 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
3532 }
3533 };
3534
3535 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
3536 return original.accept(methodWithReturn, newReturn);
3537 }
3538 // where
3539 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
3540 public Type visitType(Type t, Type newReturn) {
3541 throw new IllegalArgumentException("Not a method type: " + t);
3542 }
3543 public Type visitMethodType(MethodType t, Type newReturn) {
3544 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) {
3545 @Override
3546 public Type baseType() {
3547 return t;
3548 }
3549 };
3550 }
3551 public Type visitForAll(ForAll t, Type newReturn) {
3552 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) {
3553 @Override
3554 public Type baseType() {
3555 return t;
3556 }
3557 };
3558 }
3559 };
3560
3561 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3562 public Type createErrorType(Type originalType) {
3563 return new ErrorType(originalType, syms.errSymbol);
3564 }
3565
3566 public Type createErrorType(ClassSymbol c, Type originalType) {
3567 return new ErrorType(c, originalType);
3568 }
3569
3570 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3571 return new ErrorType(name, container, originalType);
3572 }
3573 // </editor-fold>
3574
3575 // <editor-fold defaultstate="collapsed" desc="rank">
3576 /**
3577 * The rank of a class is the length of the longest path between
3578 * the class and java.lang.Object in the class inheritance
3579 * graph. Undefined for all but reference types.
3580 */
3581 public int rank(Type t) {
3582 switch(t.getTag()) {
3583 case CLASS: {
3584 ClassType cls = (ClassType)t;
3585 if (cls.rank_field < 0) {
3586 Name fullname = cls.tsym.getQualifiedName();
3587 if (fullname == names.java_lang_Object)
3588 cls.rank_field = 0;
3589 else {
3590 int r = rank(supertype(cls));
3591 for (List<Type> l = interfaces(cls);
3592 l.nonEmpty();
3593 l = l.tail) {
3594 if (rank(l.head) > r)
3595 r = rank(l.head);
3596 }
3597 cls.rank_field = r + 1;
3598 }
3599 }
3600 return cls.rank_field;
3601 }
3602 case TYPEVAR: {
3603 TypeVar tvar = (TypeVar)t;
3604 if (tvar.rank_field < 0) {
3605 int r = rank(supertype(tvar));
3606 for (List<Type> l = interfaces(tvar);
3607 l.nonEmpty();
3608 l = l.tail) {
3609 if (rank(l.head) > r) r = rank(l.head);
3610 }
3611 tvar.rank_field = r + 1;
3612 }
3613 return tvar.rank_field;
3614 }
3615 case ERROR:
3616 case NONE:
3617 return 0;
3618 default:
3619 throw new AssertionError();
3620 }
3621 }
3622 // </editor-fold>
3623
3624 /**
3625 * Helper method for generating a string representation of a given type
3626 * accordingly to a given locale
3627 */
3628 public String toString(Type t, Locale locale) {
3629 return Printer.createStandardPrinter(messages).visit(t, locale);
3630 }
3631
3632 /**
3633 * Helper method for generating a string representation of a given type
3634 * accordingly to a given locale
3635 */
3636 public String toString(Symbol t, Locale locale) {
3637 return Printer.createStandardPrinter(messages).visit(t, locale);
3638 }
3639
3640 // <editor-fold defaultstate="collapsed" desc="toString">
3641 /**
3642 * This toString is slightly more descriptive than the one on Type.
3643 *
3644 * @deprecated Types.toString(Type t, Locale l) provides better support
3645 * for localization
3646 */
3647 @Deprecated
3648 public String toString(Type t) {
3649 if (t.hasTag(FORALL)) {
3650 ForAll forAll = (ForAll)t;
3651 return typaramsString(forAll.tvars) + forAll.qtype;
3652 }
3653 return "" + t;
3654 }
3655 // where
3656 private String typaramsString(List<Type> tvars) {
3657 StringBuilder s = new StringBuilder();
3658 s.append('<');
3659 boolean first = true;
3660 for (Type t : tvars) {
3661 if (!first) s.append(", ");
3662 first = false;
3663 appendTyparamString(((TypeVar)t), s);
3664 }
3665 s.append('>');
3666 return s.toString();
3667 }
3668 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3669 buf.append(t);
3670 if (t.getUpperBound() == null ||
3671 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object)
3672 return;
3673 buf.append(" extends "); // Java syntax; no need for i18n
3674 Type bound = t.getUpperBound();
3675 if (!bound.isCompound()) {
3676 buf.append(bound);
3677 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3678 buf.append(supertype(t));
3679 for (Type intf : interfaces(t)) {
3680 buf.append('&');
3681 buf.append(intf);
3682 }
3683 } else {
3684 // No superclass was given in bounds.
3685 // In this case, supertype is Object, erasure is first interface.
3686 boolean first = true;
3687 for (Type intf : interfaces(t)) {
3688 if (!first) buf.append('&');
3689 first = false;
3690 buf.append(intf);
3691 }
3692 }
3693 }
3694 // </editor-fold>
3695
3696 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3697 /**
3698 * A cache for closures.
3699 *
3700 * <p>A closure is a list of all the supertypes and interfaces of
3701 * a class or interface type, ordered by ClassSymbol.precedes
3702 * (that is, subclasses come first, arbitrary but fixed
3703 * otherwise).
3704 */
3705 private Map<Type,List<Type>> closureCache = new HashMap<>();
3706
3707 /**
3708 * Returns the closure of a class or interface type.
3709 */
3710 public List<Type> closure(Type t) {
3711 List<Type> cl = closureCache.get(t);
3712 if (cl == null) {
3713 Type st = supertype(t);
3714 if (!t.isCompound()) {
3715 if (st.hasTag(CLASS)) {
3716 cl = insert(closure(st), t);
3717 } else if (st.hasTag(TYPEVAR)) {
3718 cl = closure(st).prepend(t);
3719 } else {
3720 cl = List.of(t);
3721 }
3722 } else {
3723 cl = closure(supertype(t));
3724 }
3725 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3726 cl = union(cl, closure(l.head));
3727 closureCache.put(t, cl);
3728 }
3729 return cl;
3730 }
3731
3732 /**
3733 * Collect types into a new closure (using a @code{ClosureHolder})
3734 */
3735 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3736 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip),
3737 ClosureHolder::add,
3738 ClosureHolder::merge,
3739 ClosureHolder::closure);
3740 }
3741 //where
3742 class ClosureHolder {
3743 List<Type> closure;
3744 final boolean minClosure;
3745 final BiPredicate<Type, Type> shouldSkip;
3746
3747 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3748 this.closure = List.nil();
3749 this.minClosure = minClosure;
3750 this.shouldSkip = shouldSkip;
3751 }
3752
3753 void add(Type type) {
3754 closure = insert(closure, type, shouldSkip);
3755 }
3756
3757 ClosureHolder merge(ClosureHolder other) {
3758 closure = union(closure, other.closure, shouldSkip);
3759 return this;
3760 }
3761
3762 List<Type> closure() {
3763 return minClosure ? closureMin(closure) : closure;
3764 }
3765 }
3766
3767 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym;
3768
3769 /**
3770 * Insert a type in a closure
3771 */
3772 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) {
3773 if (cl.isEmpty()) {
3774 return cl.prepend(t);
3775 } else if (shouldSkip.test(t, cl.head)) {
3776 return cl;
3777 } else if (t.tsym.precedes(cl.head.tsym, this)) {
3778 return cl.prepend(t);
3779 } else {
3780 // t comes after head, or the two are unrelated
3781 return insert(cl.tail, t, shouldSkip).prepend(cl.head);
3782 }
3783 }
3784
3785 public List<Type> insert(List<Type> cl, Type t) {
3786 return insert(cl, t, basicClosureSkip);
3787 }
3788
3789 /**
3790 * Form the union of two closures
3791 */
3792 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) {
3793 if (cl1.isEmpty()) {
3794 return cl2;
3795 } else if (cl2.isEmpty()) {
3796 return cl1;
3797 } else if (shouldSkip.test(cl1.head, cl2.head)) {
3798 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
3799 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3800 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
3801 } else {
3802 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
3803 }
3804 }
3805
3806 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3807 return union(cl1, cl2, basicClosureSkip);
3808 }
3809
3810 /**
3811 * Intersect two closures
3812 */
3813 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3814 if (cl1 == cl2)
3815 return cl1;
3816 if (cl1.isEmpty() || cl2.isEmpty())
3817 return List.nil();
3818 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3819 return intersect(cl1.tail, cl2);
3820 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3821 return intersect(cl1, cl2.tail);
3822 if (isSameType(cl1.head, cl2.head))
3823 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3824 if (cl1.head.tsym == cl2.head.tsym &&
3825 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) {
3826 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3827 Type merge = merge(cl1.head,cl2.head);
3828 return intersect(cl1.tail, cl2.tail).prepend(merge);
3829 }
3830 if (cl1.head.isRaw() || cl2.head.isRaw())
3831 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3832 }
3833 return intersect(cl1.tail, cl2.tail);
3834 }
3835 // where
3836 class TypePair {
3837 final Type t1;
3838 final Type t2;;
3839
3840 TypePair(Type t1, Type t2) {
3841 this.t1 = t1;
3842 this.t2 = t2;
3843 }
3844 @Override
3845 public int hashCode() {
3846 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3847 }
3848 @Override
3849 public boolean equals(Object obj) {
3850 return (obj instanceof TypePair typePair)
3851 && isSameType(t1, typePair.t1)
3852 && isSameType(t2, typePair.t2);
3853 }
3854 }
3855 Set<TypePair> mergeCache = new HashSet<>();
3856 private Type merge(Type c1, Type c2) {
3857 ClassType class1 = (ClassType) c1;
3858 List<Type> act1 = class1.getTypeArguments();
3859 ClassType class2 = (ClassType) c2;
3860 List<Type> act2 = class2.getTypeArguments();
3861 ListBuffer<Type> merged = new ListBuffer<>();
3862 List<Type> typarams = class1.tsym.type.getTypeArguments();
3863
3864 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3865 if (containsType(act1.head, act2.head)) {
3866 merged.append(act1.head);
3867 } else if (containsType(act2.head, act1.head)) {
3868 merged.append(act2.head);
3869 } else {
3870 TypePair pair = new TypePair(c1, c2);
3871 Type m;
3872 if (mergeCache.add(pair)) {
3873 m = new WildcardType(lub(wildUpperBound(act1.head),
3874 wildUpperBound(act2.head)),
3875 BoundKind.EXTENDS,
3876 syms.boundClass);
3877 mergeCache.remove(pair);
3878 } else {
3879 m = new WildcardType(syms.objectType,
3880 BoundKind.UNBOUND,
3881 syms.boundClass);
3882 }
3883 merged.append(m.withTypeVar(typarams.head));
3884 }
3885 act1 = act1.tail;
3886 act2 = act2.tail;
3887 typarams = typarams.tail;
3888 }
3889 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3890 // There is no spec detailing how type annotations are to
3891 // be inherited. So set it to noAnnotations for now
3892 return new ClassType(class1.getEnclosingType(), merged.toList(),
3893 class1.tsym);
3894 }
3895
3896 /**
3897 * Return the minimum type of a closure, a compound type if no
3898 * unique minimum exists.
3899 */
3900 private Type compoundMin(List<Type> cl) {
3901 if (cl.isEmpty()) return syms.objectType;
3902 List<Type> compound = closureMin(cl);
3903 if (compound.isEmpty())
3904 return null;
3905 else if (compound.tail.isEmpty())
3906 return compound.head;
3907 else
3908 return makeIntersectionType(compound);
3909 }
3910
3911 /**
3912 * Return the minimum types of a closure, suitable for computing
3913 * compoundMin or glb.
3914 */
3915 private List<Type> closureMin(List<Type> cl) {
3916 ListBuffer<Type> classes = new ListBuffer<>();
3917 ListBuffer<Type> interfaces = new ListBuffer<>();
3918 Set<Type> toSkip = new HashSet<>();
3919 while (!cl.isEmpty()) {
3920 Type current = cl.head;
3921 boolean keep = !toSkip.contains(current);
3922 if (keep && current.hasTag(TYPEVAR)) {
3923 // skip lower-bounded variables with a subtype in cl.tail
3924 for (Type t : cl.tail) {
3925 if (isSubtypeNoCapture(t, current)) {
3926 keep = false;
3927 break;
3928 }
3929 }
3930 }
3931 if (keep) {
3932 if (current.isInterface())
3933 interfaces.append(current);
3934 else
3935 classes.append(current);
3936 for (Type t : cl.tail) {
3937 // skip supertypes of 'current' in cl.tail
3938 if (isSubtypeNoCapture(current, t))
3939 toSkip.add(t);
3940 }
3941 }
3942 cl = cl.tail;
3943 }
3944 return classes.appendList(interfaces).toList();
3945 }
3946
3947 /**
3948 * Return the least upper bound of list of types. if the lub does
3949 * not exist return null.
3950 */
3951 public Type lub(List<Type> ts) {
3952 return lub(ts.toArray(new Type[ts.length()]));
3953 }
3954
3955 /**
3956 * Return the least upper bound (lub) of set of types. If the lub
3957 * does not exist return the type of null (bottom).
3958 */
3959 public Type lub(Type... ts) {
3960 final int UNKNOWN_BOUND = 0;
3961 final int ARRAY_BOUND = 1;
3962 final int CLASS_BOUND = 2;
3963
3964 int[] kinds = new int[ts.length];
3965
3966 int boundkind = UNKNOWN_BOUND;
3967 for (int i = 0 ; i < ts.length ; i++) {
3968 Type t = ts[i];
3969 switch (t.getTag()) {
3970 case CLASS:
3971 boundkind |= kinds[i] = CLASS_BOUND;
3972 break;
3973 case ARRAY:
3974 boundkind |= kinds[i] = ARRAY_BOUND;
3975 break;
3976 case TYPEVAR:
3977 do {
3978 t = t.getUpperBound();
3979 } while (t.hasTag(TYPEVAR));
3980 if (t.hasTag(ARRAY)) {
3981 boundkind |= kinds[i] = ARRAY_BOUND;
3982 } else {
3983 boundkind |= kinds[i] = CLASS_BOUND;
3984 }
3985 break;
3986 default:
3987 kinds[i] = UNKNOWN_BOUND;
3988 if (t.isPrimitive())
3989 return syms.errType;
3990 }
3991 }
3992 switch (boundkind) {
3993 case 0:
3994 return syms.botType;
3995
3996 case ARRAY_BOUND:
3997 // calculate lub(A[], B[])
3998 Type[] elements = new Type[ts.length];
3999 for (int i = 0 ; i < ts.length ; i++) {
4000 Type elem = elements[i] = elemTypeFun.apply(ts[i]);
4001 if (elem.isPrimitive()) {
4002 // if a primitive type is found, then return
4003 // arraySuperType unless all the types are the
4004 // same
4005 Type first = ts[0];
4006 for (int j = 1 ; j < ts.length ; j++) {
4007 if (!isSameType(first, ts[j])) {
4008 // lub(int[], B[]) is Cloneable & Serializable
4009 return arraySuperType();
4010 }
4011 }
4012 // all the array types are the same, return one
4013 // lub(int[], int[]) is int[]
4014 return first;
4015 }
4016 }
4017 // lub(A[], B[]) is lub(A, B)[]
4018 return new ArrayType(lub(elements), syms.arrayClass);
4019
4020 case CLASS_BOUND:
4021 // calculate lub(A, B)
4022 int startIdx = 0;
4023 for (int i = 0; i < ts.length ; i++) {
4024 Type t = ts[i];
4025 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) {
4026 break;
4027 } else {
4028 startIdx++;
4029 }
4030 }
4031 Assert.check(startIdx < ts.length);
4032 //step 1 - compute erased candidate set (EC)
4033 List<Type> cl = erasedSupertypes(ts[startIdx]);
4034 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4035 Type t = ts[i];
4036 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
4037 cl = intersect(cl, erasedSupertypes(t));
4038 }
4039 //step 2 - compute minimal erased candidate set (MEC)
4040 List<Type> mec = closureMin(cl);
4041 //step 3 - for each element G in MEC, compute lci(Inv(G))
4042 List<Type> candidates = List.nil();
4043 for (Type erasedSupertype : mec) {
4044 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
4045 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4046 Type superType = asSuper(ts[i], erasedSupertype.tsym);
4047 lci = intersect(lci, superType != null ? List.of(superType) : List.nil());
4048 }
4049 candidates = candidates.appendList(lci);
4050 }
4051 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
4052 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
4053 return compoundMin(candidates);
4054
4055 default:
4056 // calculate lub(A, B[])
4057 List<Type> classes = List.of(arraySuperType());
4058 for (int i = 0 ; i < ts.length ; i++) {
4059 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays
4060 classes = classes.prepend(ts[i]);
4061 }
4062 // lub(A, B[]) is lub(A, arraySuperType)
4063 return lub(classes);
4064 }
4065 }
4066 // where
4067 List<Type> erasedSupertypes(Type t) {
4068 ListBuffer<Type> buf = new ListBuffer<>();
4069 for (Type sup : closure(t)) {
4070 if (sup.hasTag(TYPEVAR)) {
4071 buf.append(sup);
4072 } else {
4073 buf.append(erasure(sup));
4074 }
4075 }
4076 return buf.toList();
4077 }
4078
4079 private Type arraySuperType;
4080 private Type arraySuperType() {
4081 // initialized lazily to avoid problems during compiler startup
4082 if (arraySuperType == null) {
4083 // JLS 10.8: all arrays implement Cloneable and Serializable.
4084 arraySuperType = makeIntersectionType(List.of(syms.serializableType,
4085 syms.cloneableType), true);
4086 }
4087 return arraySuperType;
4088 }
4089 // </editor-fold>
4090
4091 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
4092 public Type glb(List<Type> ts) {
4093 Type t1 = ts.head;
4094 for (Type t2 : ts.tail) {
4095 if (t1.isErroneous())
4096 return t1;
4097 t1 = glb(t1, t2);
4098 }
4099 return t1;
4100 }
4101 //where
4102 public Type glb(Type t, Type s) {
4103 if (s == null)
4104 return t;
4105 else if (t.isPrimitive() || s.isPrimitive())
4106 return syms.errType;
4107 else if (isSubtypeNoCapture(t, s))
4108 return t;
4109 else if (isSubtypeNoCapture(s, t))
4110 return s;
4111
4112 List<Type> closure = union(closure(t), closure(s));
4113 return glbFlattened(closure, t);
4114 }
4115 //where
4116 /**
4117 * Perform glb for a list of non-primitive, non-error, non-compound types;
4118 * redundant elements are removed. Bounds should be ordered according to
4119 * {@link Symbol#precedes(TypeSymbol,Types)}.
4120 *
4121 * @param flatBounds List of type to glb
4122 * @param errT Original type to use if the result is an error type
4123 */
4124 private Type glbFlattened(List<Type> flatBounds, Type errT) {
4125 List<Type> bounds = closureMin(flatBounds);
4126
4127 if (bounds.isEmpty()) { // length == 0
4128 return syms.objectType;
4129 } else if (bounds.tail.isEmpty()) { // length == 1
4130 return bounds.head;
4131 } else { // length > 1
4132 int classCount = 0;
4133 List<Type> cvars = List.nil();
4134 List<Type> lowers = List.nil();
4135 for (Type bound : bounds) {
4136 if (!bound.isInterface()) {
4137 classCount++;
4138 Type lower = cvarLowerBound(bound);
4139 if (bound != lower && !lower.hasTag(BOT)) {
4140 cvars = cvars.append(bound);
4141 lowers = lowers.append(lower);
4142 }
4143 }
4144 }
4145 if (classCount > 1) {
4146 if (lowers.isEmpty()) {
4147 return createErrorType(errT);
4148 } else {
4149 // try again with lower bounds included instead of capture variables
4150 List<Type> newBounds = bounds.diff(cvars).appendList(lowers);
4151 return glb(newBounds);
4152 }
4153 }
4154 }
4155 return makeIntersectionType(bounds);
4156 }
4157 // </editor-fold>
4158
4159 // <editor-fold defaultstate="collapsed" desc="hashCode">
4160 /**
4161 * Compute a hash code on a type.
4162 */
4163 public int hashCode(Type t) {
4164 return hashCode(t, false);
4165 }
4166
4167 public int hashCode(Type t, boolean strict) {
4168 return strict ?
4169 hashCodeStrictVisitor.visit(t) :
4170 hashCodeVisitor.visit(t);
4171 }
4172 // where
4173 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor();
4174 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() {
4175 @Override
4176 public Integer visitTypeVar(TypeVar t, Void ignored) {
4177 return System.identityHashCode(t);
4178 }
4179 };
4180
4181 private static class HashCodeVisitor extends UnaryVisitor<Integer> {
4182 public Integer visitType(Type t, Void ignored) {
4183 return t.getTag().ordinal();
4184 }
4185
4186 @Override
4187 public Integer visitClassType(ClassType t, Void ignored) {
4188 int result = visit(t.getEnclosingType());
4189 result *= 127;
4190 result += t.tsym.flatName().hashCode();
4191 for (Type s : t.getTypeArguments()) {
4192 result *= 127;
4193 result += visit(s);
4194 }
4195 return result;
4196 }
4197
4198 @Override
4199 public Integer visitMethodType(MethodType t, Void ignored) {
4200 int h = METHOD.ordinal();
4201 for (List<Type> thisargs = t.argtypes;
4202 thisargs.tail != null;
4203 thisargs = thisargs.tail)
4204 h = (h << 5) + visit(thisargs.head);
4205 return (h << 5) + visit(t.restype);
4206 }
4207
4208 @Override
4209 public Integer visitWildcardType(WildcardType t, Void ignored) {
4210 int result = t.kind.hashCode();
4211 if (t.type != null) {
4212 result *= 127;
4213 result += visit(t.type);
4214 }
4215 return result;
4216 }
4217
4218 @Override
4219 public Integer visitArrayType(ArrayType t, Void ignored) {
4220 return visit(t.elemtype) + 12;
4221 }
4222
4223 @Override
4224 public Integer visitTypeVar(TypeVar t, Void ignored) {
4225 return System.identityHashCode(t);
4226 }
4227
4228 @Override
4229 public Integer visitUndetVar(UndetVar t, Void ignored) {
4230 return System.identityHashCode(t);
4231 }
4232
4233 @Override
4234 public Integer visitErrorType(ErrorType t, Void ignored) {
4235 return 0;
4236 }
4237 }
4238 // </editor-fold>
4239
4240 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
4241 /**
4242 * Does t have a result that is a subtype of the result type of s,
4243 * suitable for covariant returns? It is assumed that both types
4244 * are (possibly polymorphic) method types. Monomorphic method
4245 * types are handled in the obvious way. Polymorphic method types
4246 * require renaming all type variables of one to corresponding
4247 * type variables in the other, where correspondence is by
4248 * position in the type parameter list. */
4249 public boolean resultSubtype(Type t, Type s, Warner warner) {
4250 List<Type> tvars = t.getTypeArguments();
4251 List<Type> svars = s.getTypeArguments();
4252 Type tres = t.getReturnType();
4253 Type sres = subst(s.getReturnType(), svars, tvars);
4254 return covariantReturnType(tres, sres, warner);
4255 }
4256
4257 /**
4258 * Return-Type-Substitutable.
4259 * @jls 8.4.5 Method Result
4260 */
4261 public boolean returnTypeSubstitutable(Type r1, Type r2) {
4262 if (hasSameArgs(r1, r2))
4263 return resultSubtype(r1, r2, noWarnings);
4264 else
4265 return covariantReturnType(r1.getReturnType(),
4266 erasure(r2.getReturnType()),
4267 noWarnings);
4268 }
4269
4270 public boolean returnTypeSubstitutable(Type r1,
4271 Type r2, Type r2res,
4272 Warner warner) {
4273 if (isSameType(r1.getReturnType(), r2res))
4274 return true;
4275 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
4276 return false;
4277
4278 if (hasSameArgs(r1, r2))
4279 return covariantReturnType(r1.getReturnType(), r2res, warner);
4280 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
4281 return true;
4282 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
4283 return false;
4284 warner.warn(LintCategory.UNCHECKED);
4285 return true;
4286 }
4287
4288 /**
4289 * Is t an appropriate return type in an overrider for a
4290 * method that returns s?
4291 */
4292 public boolean covariantReturnType(Type t, Type s, Warner warner) {
4293 return
4294 isSameType(t, s) ||
4295 !t.isPrimitive() &&
4296 !s.isPrimitive() &&
4297 isAssignable(t, s, warner);
4298 }
4299 // </editor-fold>
4300
4301 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
4302 /**
4303 * Return the class that boxes the given primitive.
4304 */
4305 public ClassSymbol boxedClass(Type t) {
4306 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]);
4307 }
4308
4309 /**
4310 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
4311 */
4312 public Type boxedTypeOrType(Type t) {
4313 return t.isPrimitive() ?
4314 boxedClass(t).type :
4315 t;
4316 }
4317
4318 /**
4319 * Return the primitive type corresponding to a boxed type.
4320 */
4321 public Type unboxedType(Type t) {
4322 if (t.hasTag(ERROR))
4323 return Type.noType;
4324 for (int i=0; i<syms.boxedName.length; i++) {
4325 Name box = syms.boxedName[i];
4326 if (box != null &&
4327 asSuper(t, syms.enterClass(syms.java_base, box)) != null)
4328 return syms.typeOfTag[i];
4329 }
4330 return Type.noType;
4331 }
4332
4333 /**
4334 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
4335 */
4336 public Type unboxedTypeOrType(Type t) {
4337 Type unboxedType = unboxedType(t);
4338 return unboxedType.hasTag(NONE) ? t : unboxedType;
4339 }
4340 // </editor-fold>
4341
4342 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
4343 /*
4344 * JLS 5.1.10 Capture Conversion:
4345 *
4346 * Let G name a generic type declaration with n formal type
4347 * parameters A1 ... An with corresponding bounds U1 ... Un. There
4348 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
4349 * where, for 1 <= i <= n:
4350 *
4351 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
4352 * Si is a fresh type variable whose upper bound is
4353 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
4354 * type.
4355 *
4356 * + If Ti is a wildcard type argument of the form ? extends Bi,
4357 * then Si is a fresh type variable whose upper bound is
4358 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
4359 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
4360 * a compile-time error if for any two classes (not interfaces)
4361 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
4362 *
4363 * + If Ti is a wildcard type argument of the form ? super Bi,
4364 * then Si is a fresh type variable whose upper bound is
4365 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
4366 *
4367 * + Otherwise, Si = Ti.
4368 *
4369 * Capture conversion on any type other than a parameterized type
4370 * (4.5) acts as an identity conversion (5.1.1). Capture
4371 * conversions never require a special action at run time and
4372 * therefore never throw an exception at run time.
4373 *
4374 * Capture conversion is not applied recursively.
4375 */
4376 /**
4377 * Capture conversion as specified by the JLS.
4378 */
4379
4380 public List<Type> capture(List<Type> ts) {
4381 List<Type> buf = List.nil();
4382 for (Type t : ts) {
4383 buf = buf.prepend(capture(t));
4384 }
4385 return buf.reverse();
4386 }
4387
4388 public Type capture(Type t) {
4389 if (!t.hasTag(CLASS)) {
4390 return t;
4391 }
4392 if (t.getEnclosingType() != Type.noType) {
4393 Type capturedEncl = capture(t.getEnclosingType());
4394 if (capturedEncl != t.getEnclosingType()) {
4395 Type type1 = memberType(capturedEncl, t.tsym);
4396 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
4397 }
4398 }
4399 ClassType cls = (ClassType)t;
4400 if (cls.isRaw() || !cls.isParameterized())
4401 return cls;
4402
4403 ClassType G = (ClassType)cls.asElement().asType();
4404 List<Type> A = G.getTypeArguments();
4405 List<Type> T = cls.getTypeArguments();
4406 List<Type> S = freshTypeVariables(T);
4407
4408 List<Type> currentA = A;
4409 List<Type> currentT = T;
4410 List<Type> currentS = S;
4411 boolean captured = false;
4412 while (!currentA.isEmpty() &&
4413 !currentT.isEmpty() &&
4414 !currentS.isEmpty()) {
4415 if (currentS.head != currentT.head) {
4416 captured = true;
4417 WildcardType Ti = (WildcardType)currentT.head;
4418 Type Ui = currentA.head.getUpperBound();
4419 CapturedType Si = (CapturedType)currentS.head;
4420 if (Ui == null)
4421 Ui = syms.objectType;
4422 switch (Ti.kind) {
4423 case UNBOUND:
4424 Si.setUpperBound( subst(Ui, A, S) );
4425 Si.lower = syms.botType;
4426 break;
4427 case EXTENDS:
4428 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) );
4429 Si.lower = syms.botType;
4430 break;
4431 case SUPER:
4432 Si.setUpperBound( subst(Ui, A, S) );
4433 Si.lower = Ti.getSuperBound();
4434 break;
4435 }
4436 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound();
4437 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower;
4438 if (!Si.getUpperBound().hasTag(ERROR) &&
4439 !Si.lower.hasTag(ERROR) &&
4440 isSameType(tmpBound, tmpLower)) {
4441 currentS.head = Si.getUpperBound();
4442 }
4443 }
4444 currentA = currentA.tail;
4445 currentT = currentT.tail;
4446 currentS = currentS.tail;
4447 }
4448 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
4449 return erasure(t); // some "rare" type involved
4450
4451 if (captured)
4452 return new ClassType(cls.getEnclosingType(), S, cls.tsym,
4453 cls.getMetadata());
4454 else
4455 return t;
4456 }
4457 // where
4458 public List<Type> freshTypeVariables(List<Type> types) {
4459 ListBuffer<Type> result = new ListBuffer<>();
4460 for (Type t : types) {
4461 if (t.hasTag(WILDCARD)) {
4462 Type bound = ((WildcardType)t).getExtendsBound();
4463 if (bound == null)
4464 bound = syms.objectType;
4465 result.append(new CapturedType(capturedName,
4466 syms.noSymbol,
4467 bound,
4468 syms.botType,
4469 (WildcardType)t));
4470 } else {
4471 result.append(t);
4472 }
4473 }
4474 return result.toList();
4475 }
4476 // </editor-fold>
4477
4478 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
4479 private boolean sideCast(Type from, Type to, Warner warn) {
4480 // We are casting from type $from$ to type $to$, which are
4481 // non-final unrelated types. This method
4482 // tries to reject a cast by transferring type parameters
4483 // from $to$ to $from$ by common superinterfaces.
4484 boolean reverse = false;
4485 Type target = to;
4486 if ((to.tsym.flags() & INTERFACE) == 0) {
4487 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4488 reverse = true;
4489 to = from;
4490 from = target;
4491 }
4492 List<Type> commonSupers = superClosure(to, erasure(from));
4493 boolean giveWarning = commonSupers.isEmpty();
4494 // The arguments to the supers could be unified here to
4495 // get a more accurate analysis
4496 while (commonSupers.nonEmpty()) {
4497 Type t1 = asSuper(from, commonSupers.head.tsym);
4498 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
4499 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4500 return false;
4501 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
4502 commonSupers = commonSupers.tail;
4503 }
4504 if (giveWarning && !isReifiable(reverse ? from : to))
4505 warn.warn(LintCategory.UNCHECKED);
4506 return true;
4507 }
4508
4509 private boolean sideCastFinal(Type from, Type to, Warner warn) {
4510 // We are casting from type $from$ to type $to$, which are
4511 // unrelated types one of which is final and the other of
4512 // which is an interface. This method
4513 // tries to reject a cast by transferring type parameters
4514 // from the final class to the interface.
4515 boolean reverse = false;
4516 Type target = to;
4517 if ((to.tsym.flags() & INTERFACE) == 0) {
4518 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4519 reverse = true;
4520 to = from;
4521 from = target;
4522 }
4523 Assert.check((from.tsym.flags() & FINAL) != 0);
4524 Type t1 = asSuper(from, to.tsym);
4525 if (t1 == null) return false;
4526 Type t2 = to;
4527 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4528 return false;
4529 if (!isReifiable(target) &&
4530 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
4531 warn.warn(LintCategory.UNCHECKED);
4532 return true;
4533 }
4534
4535 private boolean giveWarning(Type from, Type to) {
4536 List<Type> bounds = to.isCompound() ?
4537 directSupertypes(to) : List.of(to);
4538 for (Type b : bounds) {
4539 Type subFrom = asSub(from, b.tsym);
4540 if (b.isParameterized() &&
4541 (!(isUnbounded(b) ||
4542 isSubtype(from, b) ||
4543 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
4544 return true;
4545 }
4546 }
4547 return false;
4548 }
4549
4550 private List<Type> superClosure(Type t, Type s) {
4551 List<Type> cl = List.nil();
4552 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
4553 if (isSubtype(s, erasure(l.head))) {
4554 cl = insert(cl, l.head);
4555 } else {
4556 cl = union(cl, superClosure(l.head, s));
4557 }
4558 }
4559 return cl;
4560 }
4561
4562 private boolean containsTypeEquivalent(Type t, Type s) {
4563 return isSameType(t, s) || // shortcut
4564 containsType(t, s) && containsType(s, t);
4565 }
4566
4567 // <editor-fold defaultstate="collapsed" desc="adapt">
4568 /**
4569 * Adapt a type by computing a substitution which maps a source
4570 * type to a target type.
4571 *
4572 * @param source the source type
4573 * @param target the target type
4574 * @param from the type variables of the computed substitution
4575 * @param to the types of the computed substitution.
4576 */
4577 public void adapt(Type source,
4578 Type target,
4579 ListBuffer<Type> from,
4580 ListBuffer<Type> to) throws AdaptFailure {
4581 new Adapter(from, to).adapt(source, target);
4582 }
4583
4584 class Adapter extends SimpleVisitor<Void, Type> {
4585
4586 ListBuffer<Type> from;
4587 ListBuffer<Type> to;
4588 Map<Symbol,Type> mapping;
4589
4590 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
4591 this.from = from;
4592 this.to = to;
4593 mapping = new HashMap<>();
4594 }
4595
4596 public void adapt(Type source, Type target) throws AdaptFailure {
4597 visit(source, target);
4598 List<Type> fromList = from.toList();
4599 List<Type> toList = to.toList();
4600 while (!fromList.isEmpty()) {
4601 Type val = mapping.get(fromList.head.tsym);
4602 if (toList.head != val)
4603 toList.head = val;
4604 fromList = fromList.tail;
4605 toList = toList.tail;
4606 }
4607 }
4608
4609 @Override
4610 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
4611 if (target.hasTag(CLASS))
4612 adaptRecursive(source.allparams(), target.allparams());
4613 return null;
4614 }
4615
4616 @Override
4617 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
4618 if (target.hasTag(ARRAY))
4619 adaptRecursive(elemtype(source), elemtype(target));
4620 return null;
4621 }
4622
4623 @Override
4624 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
4625 if (source.isExtendsBound())
4626 adaptRecursive(wildUpperBound(source), wildUpperBound(target));
4627 else if (source.isSuperBound())
4628 adaptRecursive(wildLowerBound(source), wildLowerBound(target));
4629 return null;
4630 }
4631
4632 @Override
4633 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
4634 // Check to see if there is
4635 // already a mapping for $source$, in which case
4636 // the old mapping will be merged with the new
4637 Type val = mapping.get(source.tsym);
4638 if (val != null) {
4639 if (val.isSuperBound() && target.isSuperBound()) {
4640 val = isSubtype(wildLowerBound(val), wildLowerBound(target))
4641 ? target : val;
4642 } else if (val.isExtendsBound() && target.isExtendsBound()) {
4643 val = isSubtype(wildUpperBound(val), wildUpperBound(target))
4644 ? val : target;
4645 } else if (!isSameType(val, target)) {
4646 throw new AdaptFailure();
4647 }
4648 } else {
4649 val = target;
4650 from.append(source);
4651 to.append(target);
4652 }
4653 mapping.put(source.tsym, val);
4654 return null;
4655 }
4656
4657 @Override
4658 public Void visitType(Type source, Type target) {
4659 return null;
4660 }
4661
4662 private Set<TypePair> cache = new HashSet<>();
4663
4664 private void adaptRecursive(Type source, Type target) {
4665 TypePair pair = new TypePair(source, target);
4666 if (cache.add(pair)) {
4667 try {
4668 visit(source, target);
4669 } finally {
4670 cache.remove(pair);
4671 }
4672 }
4673 }
4674
4675 private void adaptRecursive(List<Type> source, List<Type> target) {
4676 if (source.length() == target.length()) {
4677 while (source.nonEmpty()) {
4678 adaptRecursive(source.head, target.head);
4679 source = source.tail;
4680 target = target.tail;
4681 }
4682 }
4683 }
4684 }
4685
4686 public static class AdaptFailure extends RuntimeException {
4687 static final long serialVersionUID = -7490231548272701566L;
4688 }
4689
4690 private void adaptSelf(Type t,
4691 ListBuffer<Type> from,
4692 ListBuffer<Type> to) {
4693 try {
4694 //if (t.tsym.type != t)
4695 adapt(t.tsym.type, t, from, to);
4696 } catch (AdaptFailure ex) {
4697 // Adapt should never fail calculating a mapping from
4698 // t.tsym.type to t as there can be no merge problem.
4699 throw new AssertionError(ex);
4700 }
4701 }
4702 // </editor-fold>
4703
4704 /**
4705 * Rewrite all type variables (universal quantifiers) in the given
4706 * type to wildcards (existential quantifiers). This is used to
4707 * determine if a cast is allowed. For example, if high is true
4708 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4709 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4710 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4711 * List<Integer>} with a warning.
4712 * @param t a type
4713 * @param high if true return an upper bound; otherwise a lower
4714 * bound
4715 * @param rewriteTypeVars only rewrite captured wildcards if false;
4716 * otherwise rewrite all type variables
4717 * @return the type rewritten with wildcards (existential
4718 * quantifiers) only
4719 */
4720 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4721 return new Rewriter(high, rewriteTypeVars).visit(t);
4722 }
4723
4724 class Rewriter extends UnaryVisitor<Type> {
4725
4726 boolean high;
4727 boolean rewriteTypeVars;
4728
4729 Rewriter(boolean high, boolean rewriteTypeVars) {
4730 this.high = high;
4731 this.rewriteTypeVars = rewriteTypeVars;
4732 }
4733
4734 @Override
4735 public Type visitClassType(ClassType t, Void s) {
4736 ListBuffer<Type> rewritten = new ListBuffer<>();
4737 boolean changed = false;
4738 for (Type arg : t.allparams()) {
4739 Type bound = visit(arg);
4740 if (arg != bound) {
4741 changed = true;
4742 }
4743 rewritten.append(bound);
4744 }
4745 if (changed)
4746 return subst(t.tsym.type,
4747 t.tsym.type.allparams(),
4748 rewritten.toList());
4749 else
4750 return t;
4751 }
4752
4753 public Type visitType(Type t, Void s) {
4754 return t;
4755 }
4756
4757 @Override
4758 public Type visitCapturedType(CapturedType t, Void s) {
4759 Type w_bound = t.wildcard.type;
4760 Type bound = w_bound.contains(t) ?
4761 erasure(w_bound) :
4762 visit(w_bound);
4763 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4764 }
4765
4766 @Override
4767 public Type visitTypeVar(TypeVar t, Void s) {
4768 if (rewriteTypeVars) {
4769 Type bound = t.getUpperBound().contains(t) ?
4770 erasure(t.getUpperBound()) :
4771 visit(t.getUpperBound());
4772 return rewriteAsWildcardType(bound, t, EXTENDS);
4773 } else {
4774 return t;
4775 }
4776 }
4777
4778 @Override
4779 public Type visitWildcardType(WildcardType t, Void s) {
4780 Type bound2 = visit(t.type);
4781 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4782 }
4783
4784 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4785 switch (bk) {
4786 case EXTENDS: return high ?
4787 makeExtendsWildcard(B(bound), formal) :
4788 makeExtendsWildcard(syms.objectType, formal);
4789 case SUPER: return high ?
4790 makeSuperWildcard(syms.botType, formal) :
4791 makeSuperWildcard(B(bound), formal);
4792 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4793 default:
4794 Assert.error("Invalid bound kind " + bk);
4795 return null;
4796 }
4797 }
4798
4799 Type B(Type t) {
4800 while (t.hasTag(WILDCARD)) {
4801 WildcardType w = (WildcardType)t;
4802 t = high ?
4803 w.getExtendsBound() :
4804 w.getSuperBound();
4805 if (t == null) {
4806 t = high ? syms.objectType : syms.botType;
4807 }
4808 }
4809 return t;
4810 }
4811 }
4812
4813
4814 /**
4815 * Create a wildcard with the given upper (extends) bound; create
4816 * an unbounded wildcard if bound is Object.
4817 *
4818 * @param bound the upper bound
4819 * @param formal the formal type parameter that will be
4820 * substituted by the wildcard
4821 */
4822 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4823 if (bound == syms.objectType) {
4824 return new WildcardType(syms.objectType,
4825 BoundKind.UNBOUND,
4826 syms.boundClass,
4827 formal);
4828 } else {
4829 return new WildcardType(bound,
4830 BoundKind.EXTENDS,
4831 syms.boundClass,
4832 formal);
4833 }
4834 }
4835
4836 /**
4837 * Create a wildcard with the given lower (super) bound; create an
4838 * unbounded wildcard if bound is bottom (type of {@code null}).
4839 *
4840 * @param bound the lower bound
4841 * @param formal the formal type parameter that will be
4842 * substituted by the wildcard
4843 */
4844 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4845 if (bound.hasTag(BOT)) {
4846 return new WildcardType(syms.objectType,
4847 BoundKind.UNBOUND,
4848 syms.boundClass,
4849 formal);
4850 } else {
4851 return new WildcardType(bound,
4852 BoundKind.SUPER,
4853 syms.boundClass,
4854 formal);
4855 }
4856 }
4857
4858 /**
4859 * A wrapper for a type that allows use in sets.
4860 */
4861 public static class UniqueType {
4862 public final Type type;
4863 final Types types;
4864
4865 public UniqueType(Type type, Types types) {
4866 this.type = type;
4867 this.types = types;
4868 }
4869
4870 public int hashCode() {
4871 return types.hashCode(type);
4872 }
4873
4874 public boolean equals(Object obj) {
4875 return (obj instanceof UniqueType uniqueType) &&
4876 types.isSameType(type, uniqueType.type);
4877 }
4878
4879 public String toString() {
4880 return type.toString();
4881 }
4882
4883 }
4884 // </editor-fold>
4885
4886 // <editor-fold defaultstate="collapsed" desc="Visitors">
4887 /**
4888 * A default visitor for types. All visitor methods except
4889 * visitType are implemented by delegating to visitType. Concrete
4890 * subclasses must provide an implementation of visitType and can
4891 * override other methods as needed.
4892 *
4893 * @param <R> the return type of the operation implemented by this
4894 * visitor; use Void if no return type is needed.
4895 * @param <S> the type of the second argument (the first being the
4896 * type itself) of the operation implemented by this visitor; use
4897 * Void if a second argument is not needed.
4898 */
4899 public abstract static class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4900 public final R visit(Type t, S s) { return t.accept(this, s); }
4901 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4902 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4903 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4904 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4905 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4906 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); }
4907 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4908 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4909 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4910 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4911 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4912 }
4913
4914 /**
4915 * A default visitor for symbols. All visitor methods except
4916 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4917 * subclasses must provide an implementation of visitSymbol and can
4918 * override other methods as needed.
4919 *
4920 * @param <R> the return type of the operation implemented by this
4921 * visitor; use Void if no return type is needed.
4922 * @param <S> the type of the second argument (the first being the
4923 * symbol itself) of the operation implemented by this visitor; use
4924 * Void if a second argument is not needed.
4925 */
4926 public abstract static class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4927 public final R visit(Symbol s, S arg) { return s.accept(this, arg); }
4928 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4929 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4930 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4931 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4932 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4933 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4934 }
4935
4936 /**
4937 * A <em>simple</em> visitor for types. This visitor is simple as
4938 * captured wildcards, for-all types (generic methods), and
4939 * undetermined type variables (part of inference) are hidden.
4940 * Captured wildcards are hidden by treating them as type
4941 * variables and the rest are hidden by visiting their qtypes.
4942 *
4943 * @param <R> the return type of the operation implemented by this
4944 * visitor; use Void if no return type is needed.
4945 * @param <S> the type of the second argument (the first being the
4946 * type itself) of the operation implemented by this visitor; use
4947 * Void if a second argument is not needed.
4948 */
4949 public abstract static class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4950 @Override
4951 public R visitCapturedType(CapturedType t, S s) {
4952 return visitTypeVar(t, s);
4953 }
4954 @Override
4955 public R visitForAll(ForAll t, S s) {
4956 return visit(t.qtype, s);
4957 }
4958 @Override
4959 public R visitUndetVar(UndetVar t, S s) {
4960 return visit(t.qtype, s);
4961 }
4962 }
4963
4964 /**
4965 * A plain relation on types. That is a 2-ary function on the
4966 * form Type × Type → Boolean.
4967 * <!-- In plain text: Type x Type -> Boolean -->
4968 */
4969 public abstract static class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4970
4971 /**
4972 * A convenience visitor for implementing operations that only
4973 * require one argument (the type itself), that is, unary
4974 * operations.
4975 *
4976 * @param <R> the return type of the operation implemented by this
4977 * visitor; use Void if no return type is needed.
4978 */
4979 public abstract static class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4980 public final R visit(Type t) { return t.accept(this, null); }
4981 }
4982
4983 /**
4984 * A visitor for implementing a mapping from types to types. The
4985 * default behavior of this class is to implement the identity
4986 * mapping (mapping a type to itself). This can be overridden in
4987 * subclasses.
4988 *
4989 * @param <S> the type of the second argument (the first being the
4990 * type itself) of this mapping; use Void if a second argument is
4991 * not needed.
4992 */
4993 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4994 public final Type visit(Type t) { return t.accept(this, null); }
4995 public Type visitType(Type t, S s) { return t; }
4996 }
4997
4998 /**
4999 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}.
5000 * This class implements the functional interface {@code Function}, that allows it to be used
5001 * fluently in stream-like processing.
5002 */
5003 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> {
5004 @Override
5005 public Type apply(Type type) { return visit(type); }
5006
5007 List<Type> visit(List<Type> ts, S s) {
5008 return ts.map(t -> visit(t, s));
5009 }
5010
5011 @Override
5012 public Type visitCapturedType(CapturedType t, S s) {
5013 return visitTypeVar(t, s);
5014 }
5015 }
5016 // </editor-fold>
5017
5018
5019 // <editor-fold defaultstate="collapsed" desc="Annotation support">
5020
5021 public RetentionPolicy getRetention(Attribute.Compound a) {
5022 return getRetention(a.type.tsym);
5023 }
5024
5025 public RetentionPolicy getRetention(TypeSymbol sym) {
5026 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
5027 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
5028 if (c != null) {
5029 Attribute value = c.member(names.value);
5030 if (value != null && value instanceof Attribute.Enum attributeEnum) {
5031 Name levelName = attributeEnum.value.name;
5032 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
5033 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
5034 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
5035 else ;// /* fail soft */ throw new AssertionError(levelName);
5036 }
5037 }
5038 return vis;
5039 }
5040 // </editor-fold>
5041
5042 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
5043
5044 public abstract static class SignatureGenerator {
5045
5046 public static class InvalidSignatureException extends RuntimeException {
5047 private static final long serialVersionUID = 0;
5048
5049 private final transient Type type;
5050
5051 InvalidSignatureException(Type type) {
5052 this.type = type;
5053 }
5054
5055 public Type type() {
5056 return type;
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.getByteLength() + 1, c.flatname.getByteLength())
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 }