1 /*
2 * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.tools.javac.code;
27
28 import java.lang.ref.SoftReference;
29 import java.util.HashSet;
30 import java.util.HashMap;
31 import java.util.Locale;
32 import java.util.Map;
33 import java.util.Optional;
34 import java.util.Set;
35 import java.util.WeakHashMap;
36 import java.util.function.BiPredicate;
37 import java.util.function.Function;
38 import java.util.function.Predicate;
39 import java.util.stream.Collector;
40
41 import javax.tools.JavaFileObject;
42
43 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
44 import com.sun.tools.javac.code.Lint.LintCategory;
45 import com.sun.tools.javac.code.Source.Feature;
46 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
47 import com.sun.tools.javac.code.TypeMetadata.Entry.Kind;
48 import com.sun.tools.javac.comp.AttrContext;
49 import com.sun.tools.javac.comp.Check;
50 import com.sun.tools.javac.comp.Enter;
51 import com.sun.tools.javac.comp.Env;
52 import com.sun.tools.javac.comp.LambdaToMethod;
53 import com.sun.tools.javac.jvm.ClassFile;
54 import com.sun.tools.javac.util.*;
55
56 import static com.sun.tools.javac.code.BoundKind.*;
57 import static com.sun.tools.javac.code.Flags.*;
58 import static com.sun.tools.javac.code.Kinds.Kind.*;
59 import static com.sun.tools.javac.code.Scope.*;
60 import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
61 import static com.sun.tools.javac.code.Symbol.*;
62 import static com.sun.tools.javac.code.Type.*;
63 import static com.sun.tools.javac.code.TypeTag.*;
64 import static com.sun.tools.javac.jvm.ClassFile.externalize;
65 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
66
67 /**
68 * Utility class containing various operations on types.
69 *
70 * <p>Unless other names are more illustrative, the following naming
71 * conventions should be observed in this file:
72 *
73 * <dl>
74 * <dt>t</dt>
75 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
76 * <dt>s</dt>
77 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
78 * <dt>ts</dt>
79 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
80 * <dt>ss</dt>
81 * <dd>A second list of types should be named ss.</dd>
82 * </dl>
83 *
84 * <p><b>This is NOT part of any supported API.
85 * If you write code that depends on this, you do so at your own risk.
86 * This code and its internal interfaces are subject to change or
87 * deletion without notice.</b>
88 */
89 public class Types {
90 protected static final Context.Key<Types> typesKey = new Context.Key<>();
91
92 final Symtab syms;
93 final JavacMessages messages;
94 final Names names;
95 final Check chk;
96 final Enter enter;
97 JCDiagnostic.Factory diags;
98 List<Warner> warnStack = List.nil();
99 final Name capturedName;
100
101 public final Warner noWarnings;
102
103 // <editor-fold defaultstate="collapsed" desc="Instantiating">
104 public static Types instance(Context context) {
105 Types instance = context.get(typesKey);
106 if (instance == null)
107 instance = new Types(context);
108 return instance;
109 }
110
111 protected Types(Context context) {
112 context.put(typesKey, this);
113 syms = Symtab.instance(context);
114 names = Names.instance(context);
115 Source source = Source.instance(context);
116 chk = Check.instance(context);
117 enter = Enter.instance(context);
118 capturedName = names.fromString("<captured wildcard>");
119 messages = JavacMessages.instance(context);
120 diags = JCDiagnostic.Factory.instance(context);
121 noWarnings = new Warner(null);
122 }
123 // </editor-fold>
124
125 // <editor-fold defaultstate="collapsed" desc="bounds">
126 /**
127 * Get a wildcard's upper bound, returning non-wildcards unchanged.
128 * @param t a type argument, either a wildcard or a type
129 */
130 public Type wildUpperBound(Type t) {
131 if (t.hasTag(WILDCARD)) {
132 WildcardType w = (WildcardType) t;
133 if (w.isSuperBound())
134 return w.bound == null ? syms.objectType : w.bound.getUpperBound();
135 else
136 return wildUpperBound(w.type);
137 }
138 else return t;
139 }
140
141 /**
142 * Get a capture variable's upper bound, returning other types unchanged.
143 * @param t a type
144 */
145 public Type cvarUpperBound(Type t) {
146 if (t.hasTag(TYPEVAR)) {
147 TypeVar v = (TypeVar) t;
148 return v.isCaptured() ? cvarUpperBound(v.getUpperBound()) : v;
149 }
150 else return t;
151 }
152
153 /**
154 * Get a wildcard's lower bound, returning non-wildcards unchanged.
155 * @param t a type argument, either a wildcard or a type
156 */
157 public Type wildLowerBound(Type t) {
158 if (t.hasTag(WILDCARD)) {
159 WildcardType w = (WildcardType) t;
160 return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type);
161 }
162 else return t;
163 }
164
165 /**
166 * Get a capture variable's lower bound, returning other types unchanged.
167 * @param t a type
168 */
169 public Type cvarLowerBound(Type t) {
170 if (t.hasTag(TYPEVAR) && ((TypeVar) t).isCaptured()) {
171 return cvarLowerBound(t.getLowerBound());
172 }
173 else return t;
174 }
175
176 /**
177 * Recursively skip type-variables until a class/array type is found; capture conversion is then
178 * (optionally) applied to the resulting type. This is useful for i.e. computing a site that is
179 * suitable for a method lookup.
180 */
181 public Type skipTypeVars(Type site, boolean capture) {
182 while (site.hasTag(TYPEVAR)) {
183 site = site.getUpperBound();
184 }
185 return capture ? capture(site) : site;
186 }
187 // </editor-fold>
188
189 // <editor-fold defaultstate="collapsed" desc="projections">
190
191 /**
192 * A projection kind. See {@link TypeProjection}
193 */
194 enum ProjectionKind {
195 UPWARDS() {
196 @Override
197 ProjectionKind complement() {
198 return DOWNWARDS;
199 }
200 },
201 DOWNWARDS() {
202 @Override
203 ProjectionKind complement() {
204 return UPWARDS;
205 }
206 };
207
208 abstract ProjectionKind complement();
209 }
210
211 /**
212 * This visitor performs upwards and downwards projections on types.
213 *
214 * A projection is defined as a function that takes a type T, a set of type variables V and that
215 * produces another type S.
216 *
217 * An upwards projection maps a type T into a type S such that (i) T has no variables in V,
218 * and (ii) S is an upper bound of T.
219 *
220 * A downwards projection maps a type T into a type S such that (i) T has no variables in V,
221 * and (ii) S is a lower bound of T.
222 *
223 * Note that projections are only allowed to touch variables in V. Therefore, it is possible for
224 * a projection to leave its input type unchanged if it does not contain any variables in V.
225 *
226 * Moreover, note that while an upwards projection is always defined (every type as an upper bound),
227 * a downwards projection is not always defined.
228 *
229 * Examples:
230 *
231 * {@code upwards(List<#CAP1>, [#CAP1]) = List<? extends String>, where #CAP1 <: String }
232 * {@code downwards(List<#CAP2>, [#CAP2]) = List<? super String>, where #CAP2 :> String }
233 * {@code upwards(List<#CAP1>, [#CAP2]) = List<#CAP1> }
234 * {@code downwards(List<#CAP1>, [#CAP1]) = not defined }
235 */
236 class TypeProjection extends TypeMapping<ProjectionKind> {
237
238 List<Type> vars;
239 Set<Type> seen = new HashSet<>();
240
241 public TypeProjection(List<Type> vars) {
242 this.vars = vars;
243 }
244
245 @Override
246 public Type visitClassType(ClassType t, ProjectionKind pkind) {
247 if (t.isCompound()) {
248 List<Type> components = directSupertypes(t);
249 List<Type> components1 = components.map(c -> c.map(this, pkind));
250 if (components == components1) return t;
251 else return makeIntersectionType(components1);
252 } else {
253 Type outer = t.getEnclosingType();
254 Type outer1 = visit(outer, pkind);
255 List<Type> typarams = t.getTypeArguments();
256 List<Type> formals = t.tsym.type.getTypeArguments();
257 ListBuffer<Type> typarams1 = new ListBuffer<>();
258 boolean changed = false;
259 for (Type actual : typarams) {
260 Type t2 = mapTypeArgument(t, formals.head.getUpperBound(), actual, pkind);
261 if (t2.hasTag(BOT)) {
262 //not defined
263 return syms.botType;
264 }
265 typarams1.add(t2);
266 changed |= actual != t2;
267 formals = formals.tail;
268 }
269 if (outer1 == outer && !changed) return t;
270 else return new ClassType(outer1, typarams1.toList(), t.tsym, t.getMetadata()) {
271 @Override
272 protected boolean needsStripping() {
273 return true;
274 }
275 };
276 }
277 }
278
279 @Override
280 public Type visitArrayType(ArrayType t, ProjectionKind s) {
281 Type elemtype = t.elemtype;
282 Type elemtype1 = visit(elemtype, s);
283 if (elemtype1 == elemtype) {
284 return t;
285 } else if (elemtype1.hasTag(BOT)) {
286 //undefined
287 return syms.botType;
288 } else {
289 return new ArrayType(elemtype1, t.tsym, t.metadata) {
290 @Override
291 protected boolean needsStripping() {
292 return true;
293 }
294 };
295 }
296 }
297
298 @Override
299 public Type visitTypeVar(TypeVar t, ProjectionKind pkind) {
300 if (vars.contains(t)) {
301 if (seen.add(t)) {
302 try {
303 final Type bound;
304 switch (pkind) {
305 case UPWARDS:
306 bound = t.getUpperBound();
307 break;
308 case DOWNWARDS:
309 bound = (t.getLowerBound() == null) ?
310 syms.botType :
311 t.getLowerBound();
312 break;
313 default:
314 Assert.error();
315 return null;
316 }
317 return bound.map(this, pkind);
318 } finally {
319 seen.remove(t);
320 }
321 } else {
322 //cycle
323 return pkind == ProjectionKind.UPWARDS ?
324 syms.objectType : syms.botType;
325 }
326 } else {
327 return t;
328 }
329 }
330
331 private Type mapTypeArgument(Type site, Type declaredBound, Type t, ProjectionKind pkind) {
332 return t.containsAny(vars) ?
333 t.map(new TypeArgumentProjection(site, declaredBound), pkind) :
334 t;
335 }
336
337 class TypeArgumentProjection extends TypeMapping<ProjectionKind> {
338
339 Type site;
340 Type declaredBound;
341
342 TypeArgumentProjection(Type site, Type declaredBound) {
343 this.site = site;
344 this.declaredBound = declaredBound;
345 }
346
347 @Override
348 public Type visitType(Type t, ProjectionKind pkind) {
349 //type argument is some type containing restricted vars
350 if (pkind == ProjectionKind.DOWNWARDS) {
351 //not defined
352 return syms.botType;
353 }
354 Type upper = t.map(TypeProjection.this, ProjectionKind.UPWARDS);
355 Type lower = t.map(TypeProjection.this, ProjectionKind.DOWNWARDS);
356 List<Type> formals = site.tsym.type.getTypeArguments();
357 BoundKind bk;
358 Type bound;
359 if (!isSameType(upper, syms.objectType) &&
360 (declaredBound.containsAny(formals) ||
361 !isSubtype(declaredBound, upper))) {
362 bound = upper;
363 bk = EXTENDS;
364 } else if (!lower.hasTag(BOT)) {
365 bound = lower;
366 bk = SUPER;
367 } else {
368 bound = syms.objectType;
369 bk = UNBOUND;
370 }
371 return makeWildcard(bound, bk);
372 }
373
374 @Override
375 public Type visitWildcardType(WildcardType wt, ProjectionKind pkind) {
376 //type argument is some wildcard whose bound contains restricted vars
377 Type bound = syms.botType;
378 BoundKind bk = wt.kind;
379 switch (wt.kind) {
380 case EXTENDS:
381 bound = wt.type.map(TypeProjection.this, pkind);
382 if (bound.hasTag(BOT)) {
383 return syms.botType;
384 }
385 break;
386 case SUPER:
387 bound = wt.type.map(TypeProjection.this, pkind.complement());
388 if (bound.hasTag(BOT)) {
389 bound = syms.objectType;
390 bk = UNBOUND;
391 }
392 break;
393 }
394 return makeWildcard(bound, bk);
395 }
396
397 private Type makeWildcard(Type bound, BoundKind bk) {
398 return new WildcardType(bound, bk, syms.boundClass) {
399 @Override
400 protected boolean needsStripping() {
401 return true;
402 }
403 };
404 }
405 }
406 }
407
408 /**
409 * Computes an upward projection of given type, and vars. See {@link TypeProjection}.
410 *
411 * @param t the type to be projected
412 * @param vars the set of type variables to be mapped
413 * @return the type obtained as result of the projection
414 */
415 public Type upward(Type t, List<Type> vars) {
416 return t.map(new TypeProjection(vars), ProjectionKind.UPWARDS);
417 }
418
419 /**
420 * Computes the set of captured variables mentioned in a given type. See {@link CaptureScanner}.
421 * This routine is typically used to computed the input set of variables to be used during
422 * an upwards projection (see {@link Types#upward(Type, List)}).
423 *
424 * @param t the type where occurrences of captured variables have to be found
425 * @return the set of captured variables found in t
426 */
427 public List<Type> captures(Type t) {
428 CaptureScanner cs = new CaptureScanner();
429 Set<Type> captures = new HashSet<>();
430 cs.visit(t, captures);
431 return List.from(captures);
432 }
433
434 /**
435 * This visitor scans a type recursively looking for occurrences of captured type variables.
436 */
437 class CaptureScanner extends SimpleVisitor<Void, Set<Type>> {
438
439 @Override
440 public Void visitType(Type t, Set<Type> types) {
441 return null;
442 }
443
444 @Override
445 public Void visitClassType(ClassType t, Set<Type> seen) {
446 if (t.isCompound()) {
447 directSupertypes(t).forEach(s -> visit(s, seen));
448 } else {
449 t.allparams().forEach(ta -> visit(ta, seen));
450 }
451 return null;
452 }
453
454 @Override
455 public Void visitArrayType(ArrayType t, Set<Type> seen) {
456 return visit(t.elemtype, seen);
457 }
458
459 @Override
460 public Void visitWildcardType(WildcardType t, Set<Type> seen) {
461 visit(t.type, seen);
462 return null;
463 }
464
465 @Override
466 public Void visitTypeVar(TypeVar t, Set<Type> seen) {
467 if ((t.tsym.flags() & Flags.SYNTHETIC) != 0 && seen.add(t)) {
468 visit(t.getUpperBound(), seen);
469 }
470 return null;
471 }
472
473 @Override
474 public Void visitCapturedType(CapturedType t, Set<Type> seen) {
475 if (seen.add(t)) {
476 visit(t.getUpperBound(), seen);
477 visit(t.getLowerBound(), seen);
478 }
479 return null;
480 }
481 }
482
483 // </editor-fold>
484
485 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
486 /**
487 * Checks that all the arguments to a class are unbounded
488 * wildcards or something else that doesn't make any restrictions
489 * on the arguments. If a class isUnbounded, a raw super- or
490 * subclass can be cast to it without a warning.
491 * @param t a type
492 * @return true iff the given type is unbounded or raw
493 */
494 public boolean isUnbounded(Type t) {
495 return isUnbounded.visit(t);
496 }
497 // where
498 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
499
500 public Boolean visitType(Type t, Void ignored) {
501 return true;
502 }
503
504 @Override
505 public Boolean visitClassType(ClassType t, Void ignored) {
506 List<Type> parms = t.tsym.type.allparams();
507 List<Type> args = t.allparams();
508 while (parms.nonEmpty()) {
509 WildcardType unb = new WildcardType(syms.objectType,
510 BoundKind.UNBOUND,
511 syms.boundClass,
512 (TypeVar)parms.head);
513 if (!containsType(args.head, unb))
514 return false;
515 parms = parms.tail;
516 args = args.tail;
517 }
518 return true;
519 }
520 };
521 // </editor-fold>
522
523 // <editor-fold defaultstate="collapsed" desc="asSub">
524 /**
525 * Return the least specific subtype of t that starts with symbol
526 * sym. If none exists, return null. The least specific subtype
527 * is determined as follows:
528 *
529 * <p>If there is exactly one parameterized instance of sym that is a
530 * subtype of t, that parameterized instance is returned.<br>
531 * Otherwise, if the plain type or raw type `sym' is a subtype of
532 * type t, the type `sym' itself is returned. Otherwise, null is
533 * returned.
534 */
535 public Type asSub(Type t, Symbol sym) {
536 return asSub.visit(t, sym);
537 }
538 // where
539 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
540
541 public Type visitType(Type t, Symbol sym) {
542 return null;
543 }
544
545 @Override
546 public Type visitClassType(ClassType t, Symbol sym) {
547 if (t.tsym == sym)
548 return t;
549 Type base = asSuper(sym.type, t.tsym);
550 if (base == null)
551 return null;
552 ListBuffer<Type> from = new ListBuffer<>();
553 ListBuffer<Type> to = new ListBuffer<>();
554 try {
555 adapt(base, t, from, to);
556 } catch (AdaptFailure ex) {
557 return null;
558 }
559 Type res = subst(sym.type, from.toList(), to.toList());
560 if (!isSubtype(res, t))
561 return null;
562 ListBuffer<Type> openVars = new ListBuffer<>();
563 for (List<Type> l = sym.type.allparams();
564 l.nonEmpty(); l = l.tail)
565 if (res.contains(l.head) && !t.contains(l.head))
566 openVars.append(l.head);
567 if (openVars.nonEmpty()) {
568 if (t.isRaw()) {
569 // The subtype of a raw type is raw
570 res = erasure(res);
571 } else {
572 // Unbound type arguments default to ?
573 List<Type> opens = openVars.toList();
574 ListBuffer<Type> qs = new ListBuffer<>();
575 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
576 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND,
577 syms.boundClass, (TypeVar) iter.head));
578 }
579 res = subst(res, opens, qs.toList());
580 }
581 }
582 return res;
583 }
584
585 @Override
586 public Type visitErrorType(ErrorType t, Symbol sym) {
587 return t;
588 }
589 };
590 // </editor-fold>
591
592 // <editor-fold defaultstate="collapsed" desc="isConvertible">
593 /**
594 * Is t a subtype of or convertible via boxing/unboxing
595 * conversion to s?
596 */
597 public boolean isConvertible(Type t, Type s, Warner warn) {
598 if (t.hasTag(ERROR)) {
599 return true;
600 }
601 boolean tPrimitive = t.isPrimitive();
602 boolean sPrimitive = s.isPrimitive();
603 if (tPrimitive == sPrimitive) {
604 return isSubtypeUnchecked(t, s, warn);
605 }
606 boolean tUndet = t.hasTag(UNDETVAR);
607 boolean sUndet = s.hasTag(UNDETVAR);
608
609 if (tUndet || sUndet) {
610 return tUndet ?
611 isSubtype(t, boxedTypeOrType(s)) :
612 isSubtype(boxedTypeOrType(t), s);
613 }
614
615 return tPrimitive
616 ? isSubtype(boxedClass(t).type, s)
617 : isSubtype(unboxedType(t), s);
618 }
619
620 /**
621 * Is t a subtype of or convertible via boxing/unboxing
622 * conversions to s?
623 */
624 public boolean isConvertible(Type t, Type s) {
625 return isConvertible(t, s, noWarnings);
626 }
627 // </editor-fold>
628
629 // <editor-fold defaultstate="collapsed" desc="findSam">
630
631 /**
632 * Exception used to report a function descriptor lookup failure. The exception
633 * wraps a diagnostic that can be used to generate more details error
634 * messages.
635 */
636 public static class FunctionDescriptorLookupError extends RuntimeException {
637 private static final long serialVersionUID = 0;
638
639 transient JCDiagnostic diagnostic;
640
641 FunctionDescriptorLookupError() {
642 this.diagnostic = null;
643 }
644
645 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
646 this.diagnostic = diag;
647 return this;
648 }
649
650 public JCDiagnostic getDiagnostic() {
651 return diagnostic;
652 }
653
654 @Override
655 public Throwable fillInStackTrace() {
656 // This is an internal exception; the stack trace is irrelevant.
657 return this;
658 }
659 }
660
661 /**
662 * A cache that keeps track of function descriptors associated with given
663 * functional interfaces.
664 */
665 class DescriptorCache {
666
667 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<>();
668
669 class FunctionDescriptor {
670 Symbol descSym;
671
672 FunctionDescriptor(Symbol descSym) {
673 this.descSym = descSym;
674 }
675
676 public Symbol getSymbol() {
677 return descSym;
678 }
679
680 public Type getType(Type site) {
681 site = removeWildcards(site);
682 if (site.isIntersection()) {
683 IntersectionClassType ict = (IntersectionClassType)site;
684 for (Type component : ict.getExplicitComponents()) {
685 if (!chk.checkValidGenericType(component)) {
686 //if the inferred functional interface type is not well-formed,
687 //or if it's not a subtype of the original target, issue an error
688 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
689 }
690 }
691 } else {
692 if (!chk.checkValidGenericType(site)) {
693 //if the inferred functional interface type is not well-formed,
694 //or if it's not a subtype of the original target, issue an error
695 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
696 }
697 }
698 return memberType(site, descSym);
699 }
700 }
701
702 class Entry {
703 final FunctionDescriptor cachedDescRes;
704 final int prevMark;
705
706 public Entry(FunctionDescriptor cachedDescRes,
707 int prevMark) {
708 this.cachedDescRes = cachedDescRes;
709 this.prevMark = prevMark;
710 }
711
712 boolean matches(int mark) {
713 return this.prevMark == mark;
714 }
715 }
716
717 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
718 Entry e = _map.get(origin);
719 CompoundScope members = membersClosure(origin.type, false);
720 if (e == null ||
721 !e.matches(members.getMark())) {
722 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
723 _map.put(origin, new Entry(descRes, members.getMark()));
724 return descRes;
725 }
726 else {
727 return e.cachedDescRes;
728 }
729 }
730
731 /**
732 * Compute the function descriptor associated with a given functional interface
733 */
734 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin,
735 CompoundScope membersCache) throws FunctionDescriptorLookupError {
736 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0 || origin.isSealed()) {
737 //t must be an interface
738 throw failure("not.a.functional.intf", origin);
739 }
740
741 final ListBuffer<Symbol> abstracts = new ListBuffer<>();
742 for (Symbol sym : membersCache.getSymbols(new DescriptorFilter(origin))) {
743 Type mtype = memberType(origin.type, sym);
744 if (abstracts.isEmpty()) {
745 abstracts.append(sym);
746 } else if ((sym.name == abstracts.first().name &&
747 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
748 if (!abstracts.stream().filter(msym -> msym.owner.isSubClass(sym.enclClass(), Types.this))
749 .map(msym -> memberType(origin.type, msym))
750 .anyMatch(abstractMType -> isSubSignature(abstractMType, mtype))) {
751 abstracts.append(sym);
752 }
753 } else {
754 //the target method(s) should be the only abstract members of t
755 throw failure("not.a.functional.intf.1", origin,
756 diags.fragment(Fragments.IncompatibleAbstracts(Kinds.kindName(origin), origin)));
757 }
758 }
759 if (abstracts.isEmpty()) {
760 //t must define a suitable non-generic method
761 throw failure("not.a.functional.intf.1", origin,
762 diags.fragment(Fragments.NoAbstracts(Kinds.kindName(origin), origin)));
763 } else if (abstracts.size() == 1) {
764 return new FunctionDescriptor(abstracts.first());
765 } else { // size > 1
766 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
767 if (descRes == null) {
768 //we can get here if the functional interface is ill-formed
769 ListBuffer<JCDiagnostic> descriptors = new ListBuffer<>();
770 for (Symbol desc : abstracts) {
771 String key = desc.type.getThrownTypes().nonEmpty() ?
772 "descriptor.throws" : "descriptor";
773 descriptors.append(diags.fragment(key, desc.name,
774 desc.type.getParameterTypes(),
775 desc.type.getReturnType(),
776 desc.type.getThrownTypes()));
777 }
778 JCDiagnostic msg =
779 diags.fragment(Fragments.IncompatibleDescsInFunctionalIntf(Kinds.kindName(origin),
780 origin));
781 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
782 new JCDiagnostic.MultilineDiagnostic(msg, descriptors.toList());
783 throw failure(incompatibleDescriptors);
784 }
785 return descRes;
786 }
787 }
788
789 /**
790 * Compute a synthetic type for the target descriptor given a list
791 * of override-equivalent methods in the functional interface type.
792 * The resulting method type is a method type that is override-equivalent
793 * and return-type substitutable with each method in the original list.
794 */
795 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
796 return mergeAbstracts(methodSyms, origin.type, false)
797 .map(bestSoFar -> new FunctionDescriptor(bestSoFar.baseSymbol()) {
798 @Override
799 public Type getType(Type origin) {
800 Type mt = memberType(origin, getSymbol());
801 return createMethodTypeWithThrown(mt, bestSoFar.type.getThrownTypes());
802 }
803 }).orElse(null);
804 }
805
806 FunctionDescriptorLookupError failure(String msg, Object... args) {
807 return failure(diags.fragment(msg, args));
808 }
809
810 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
811 return new FunctionDescriptorLookupError().setMessage(diag);
812 }
813 }
814
815 private DescriptorCache descCache = new DescriptorCache();
816
817 /**
818 * Find the method descriptor associated to this class symbol - if the
819 * symbol 'origin' is not a functional interface, an exception is thrown.
820 */
821 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
822 return descCache.get(origin).getSymbol();
823 }
824
825 /**
826 * Find the type of the method descriptor associated to this class symbol -
827 * if the symbol 'origin' is not a functional interface, an exception is thrown.
828 */
829 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
830 return descCache.get(origin.tsym).getType(origin);
831 }
832
833 /**
834 * Is given type a functional interface?
835 */
836 public boolean isFunctionalInterface(TypeSymbol tsym) {
837 try {
838 findDescriptorSymbol(tsym);
839 return true;
840 } catch (FunctionDescriptorLookupError ex) {
841 return false;
842 }
843 }
844
845 public boolean isFunctionalInterface(Type site) {
846 try {
847 findDescriptorType(site);
848 return true;
849 } catch (FunctionDescriptorLookupError ex) {
850 return false;
851 }
852 }
853
854 public Type removeWildcards(Type site) {
855 if (site.getTypeArguments().stream().anyMatch(t -> t.hasTag(WILDCARD))) {
856 //compute non-wildcard parameterization - JLS 9.9
857 List<Type> actuals = site.getTypeArguments();
858 List<Type> formals = site.tsym.type.getTypeArguments();
859 ListBuffer<Type> targs = new ListBuffer<>();
860 for (Type formal : formals) {
861 Type actual = actuals.head;
862 Type bound = formal.getUpperBound();
863 if (actuals.head.hasTag(WILDCARD)) {
864 WildcardType wt = (WildcardType)actual;
865 //check that bound does not contain other formals
866 if (bound.containsAny(formals)) {
867 targs.add(wt.type);
868 } else {
869 //compute new type-argument based on declared bound and wildcard bound
870 switch (wt.kind) {
871 case UNBOUND:
872 targs.add(bound);
873 break;
874 case EXTENDS:
875 targs.add(glb(bound, wt.type));
876 break;
877 case SUPER:
878 targs.add(wt.type);
879 break;
880 default:
881 Assert.error("Cannot get here!");
882 }
883 }
884 } else {
885 //not a wildcard - the new type argument remains unchanged
886 targs.add(actual);
887 }
888 actuals = actuals.tail;
889 }
890 return subst(site.tsym.type, formals, targs.toList());
891 } else {
892 return site;
893 }
894 }
895
896 /**
897 * Create a symbol for a class that implements a given functional interface
898 * and overrides its functional descriptor. This routine is used for two
899 * main purposes: (i) checking well-formedness of a functional interface;
900 * (ii) perform functional interface bridge calculation.
901 */
902 public ClassSymbol makeFunctionalInterfaceClass(Env<AttrContext> env, Name name, Type target, long cflags) {
903 if (target == null || target == syms.unknownType) {
904 return null;
905 }
906 Symbol descSym = findDescriptorSymbol(target.tsym);
907 Type descType = findDescriptorType(target);
908 ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass());
909 csym.completer = Completer.NULL_COMPLETER;
910 csym.members_field = WriteableScope.create(csym);
911 MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym);
912 csym.members_field.enter(instDescSym);
913 Type.ClassType ctype = new Type.ClassType(Type.noType, List.nil(), csym);
914 ctype.supertype_field = syms.objectType;
915 ctype.interfaces_field = target.isIntersection() ?
916 directSupertypes(target) :
917 List.of(target);
918 csym.type = ctype;
919 csym.sourcefile = ((ClassSymbol)csym.owner).sourcefile;
920 return csym;
921 }
922
923 /**
924 * Find the minimal set of methods that are overridden by the functional
925 * descriptor in 'origin'. All returned methods are assumed to have different
926 * erased signatures.
927 */
928 public List<Symbol> functionalInterfaceBridges(TypeSymbol origin) {
929 Assert.check(isFunctionalInterface(origin));
930 Symbol descSym = findDescriptorSymbol(origin);
931 CompoundScope members = membersClosure(origin.type, false);
932 ListBuffer<Symbol> overridden = new ListBuffer<>();
933 outer: for (Symbol m2 : members.getSymbolsByName(descSym.name, bridgeFilter)) {
934 if (m2 == descSym) continue;
935 else if (descSym.overrides(m2, origin, Types.this, false)) {
936 for (Symbol m3 : overridden) {
937 if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) ||
938 (m3.overrides(m2, origin, Types.this, false) &&
939 (pendingBridges((ClassSymbol)origin, m3.enclClass()) ||
940 (((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) {
941 continue outer;
942 }
943 }
944 overridden.add(m2);
945 }
946 }
947 return overridden.toList();
948 }
949 //where
950 // Use anonymous class instead of lambda expression intentionally,
951 // because the variable `names` has modifier: final.
952 private Predicate<Symbol> bridgeFilter = new Predicate<Symbol>() {
953 public boolean test(Symbol t) {
954 return t.kind == MTH &&
955 t.name != names.init &&
956 t.name != names.clinit &&
957 (t.flags() & SYNTHETIC) == 0;
958 }
959 };
960
961 private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) {
962 //a symbol will be completed from a classfile if (a) symbol has
963 //an associated file object with CLASS kind and (b) the symbol has
964 //not been entered
965 if (origin.classfile != null &&
966 origin.classfile.getKind() == JavaFileObject.Kind.CLASS &&
967 enter.getEnv(origin) == null) {
968 return false;
969 }
970 if (origin == s) {
971 return true;
972 }
973 for (Type t : interfaces(origin.type)) {
974 if (pendingBridges((ClassSymbol)t.tsym, s)) {
975 return true;
976 }
977 }
978 return false;
979 }
980 // </editor-fold>
981
982 /**
983 * Scope filter used to skip methods that should be ignored (such as methods
984 * overridden by j.l.Object) during function interface conversion interface check
985 */
986 class DescriptorFilter implements Predicate<Symbol> {
987
988 TypeSymbol origin;
989
990 DescriptorFilter(TypeSymbol origin) {
991 this.origin = origin;
992 }
993
994 @Override
995 public boolean test(Symbol sym) {
996 return sym.kind == MTH &&
997 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
998 !overridesObjectMethod(origin, sym) &&
999 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
1000 }
1001 }
1002
1003 // <editor-fold defaultstate="collapsed" desc="isSubtype">
1004 /**
1005 * Is t an unchecked subtype of s?
1006 */
1007 public boolean isSubtypeUnchecked(Type t, Type s) {
1008 return isSubtypeUnchecked(t, s, noWarnings);
1009 }
1010 /**
1011 * Is t an unchecked subtype of s?
1012 */
1013 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
1014 boolean result = isSubtypeUncheckedInternal(t, s, true, warn);
1015 if (result) {
1016 checkUnsafeVarargsConversion(t, s, warn);
1017 }
1018 return result;
1019 }
1020 //where
1021 private boolean isSubtypeUncheckedInternal(Type t, Type s, boolean capture, Warner warn) {
1022 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
1023 if (((ArrayType)t).elemtype.isPrimitive()) {
1024 return isSameType(elemtype(t), elemtype(s));
1025 } else {
1026 return isSubtypeUncheckedInternal(elemtype(t), elemtype(s), false, warn);
1027 }
1028 } else if (isSubtype(t, s, capture)) {
1029 return true;
1030 } else if (t.hasTag(TYPEVAR)) {
1031 return isSubtypeUncheckedInternal(t.getUpperBound(), s, false, warn);
1032 } else if (!s.isRaw()) {
1033 Type t2 = asSuper(t, s.tsym);
1034 if (t2 != null && t2.isRaw()) {
1035 if (isReifiable(s)) {
1036 warn.silentWarn(LintCategory.UNCHECKED);
1037 } else {
1038 warn.warn(LintCategory.UNCHECKED);
1039 }
1040 return true;
1041 }
1042 }
1043 return false;
1044 }
1045
1046 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
1047 if (!t.hasTag(ARRAY) || isReifiable(t)) {
1048 return;
1049 }
1050 ArrayType from = (ArrayType)t;
1051 boolean shouldWarn = false;
1052 switch (s.getTag()) {
1053 case ARRAY:
1054 ArrayType to = (ArrayType)s;
1055 shouldWarn = from.isVarargs() &&
1056 !to.isVarargs() &&
1057 !isReifiable(from);
1058 break;
1059 case CLASS:
1060 shouldWarn = from.isVarargs();
1061 break;
1062 }
1063 if (shouldWarn) {
1064 warn.warn(LintCategory.VARARGS);
1065 }
1066 }
1067
1068 /**
1069 * Is t a subtype of s?<br>
1070 * (not defined for Method and ForAll types)
1071 */
1072 public final boolean isSubtype(Type t, Type s) {
1073 return isSubtype(t, s, true);
1074 }
1075 public final boolean isSubtypeNoCapture(Type t, Type s) {
1076 return isSubtype(t, s, false);
1077 }
1078 public boolean isSubtype(Type t, Type s, boolean capture) {
1079 if (t.equalsIgnoreMetadata(s))
1080 return true;
1081 if (s.isPartial())
1082 return isSuperType(s, t);
1083
1084 if (s.isCompound()) {
1085 for (Type s2 : interfaces(s).prepend(supertype(s))) {
1086 if (!isSubtype(t, s2, capture))
1087 return false;
1088 }
1089 return true;
1090 }
1091
1092 // Generally, if 's' is a lower-bounded type variable, recur on lower bound; but
1093 // for inference variables and intersections, we need to keep 's'
1094 // (see JLS 4.10.2 for intersections and 18.2.3 for inference vars)
1095 if (!t.hasTag(UNDETVAR) && !t.isCompound()) {
1096 // TODO: JDK-8039198, bounds checking sometimes passes in a wildcard as s
1097 Type lower = cvarLowerBound(wildLowerBound(s));
1098 if (s != lower && !lower.hasTag(BOT))
1099 return isSubtype(capture ? capture(t) : t, lower, false);
1100 }
1101
1102 return isSubtype.visit(capture ? capture(t) : t, s);
1103 }
1104 // where
1105 private TypeRelation isSubtype = new TypeRelation()
1106 {
1107 @Override
1108 public Boolean visitType(Type t, Type s) {
1109 switch (t.getTag()) {
1110 case BYTE:
1111 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
1112 case CHAR:
1113 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
1114 case SHORT: case INT: case LONG:
1115 case FLOAT: case DOUBLE:
1116 return t.getTag().isSubRangeOf(s.getTag());
1117 case BOOLEAN: case VOID:
1118 return t.hasTag(s.getTag());
1119 case TYPEVAR:
1120 return isSubtypeNoCapture(t.getUpperBound(), s);
1121 case BOT:
1122 return
1123 s.hasTag(BOT) || s.hasTag(CLASS) ||
1124 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
1125 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
1126 case NONE:
1127 return false;
1128 default:
1129 throw new AssertionError("isSubtype " + t.getTag());
1130 }
1131 }
1132
1133 private Set<TypePair> cache = new HashSet<>();
1134
1135 private boolean containsTypeRecursive(Type t, Type s) {
1136 TypePair pair = new TypePair(t, s);
1137 if (cache.add(pair)) {
1138 try {
1139 return containsType(t.getTypeArguments(),
1140 s.getTypeArguments());
1141 } finally {
1142 cache.remove(pair);
1143 }
1144 } else {
1145 return containsType(t.getTypeArguments(),
1146 rewriteSupers(s).getTypeArguments());
1147 }
1148 }
1149
1150 private Type rewriteSupers(Type t) {
1151 if (!t.isParameterized())
1152 return t;
1153 ListBuffer<Type> from = new ListBuffer<>();
1154 ListBuffer<Type> to = new ListBuffer<>();
1155 adaptSelf(t, from, to);
1156 if (from.isEmpty())
1157 return t;
1158 ListBuffer<Type> rewrite = new ListBuffer<>();
1159 boolean changed = false;
1160 for (Type orig : to.toList()) {
1161 Type s = rewriteSupers(orig);
1162 if (s.isSuperBound() && !s.isExtendsBound()) {
1163 s = new WildcardType(syms.objectType,
1164 BoundKind.UNBOUND,
1165 syms.boundClass,
1166 s.getMetadata());
1167 changed = true;
1168 } else if (s != orig) {
1169 s = new WildcardType(wildUpperBound(s),
1170 BoundKind.EXTENDS,
1171 syms.boundClass,
1172 s.getMetadata());
1173 changed = true;
1174 }
1175 rewrite.append(s);
1176 }
1177 if (changed)
1178 return subst(t.tsym.type, from.toList(), rewrite.toList());
1179 else
1180 return t;
1181 }
1182
1183 @Override
1184 public Boolean visitClassType(ClassType t, Type s) {
1185 Type sup = asSuper(t, s.tsym);
1186 if (sup == null) return false;
1187 // If t is an intersection, sup might not be a class type
1188 if (!sup.hasTag(CLASS)) return isSubtypeNoCapture(sup, s);
1189 return sup.tsym == s.tsym
1190 // Check type variable containment
1191 && (!s.isParameterized() || containsTypeRecursive(s, sup))
1192 && isSubtypeNoCapture(sup.getEnclosingType(),
1193 s.getEnclosingType());
1194 }
1195
1196 @Override
1197 public Boolean visitArrayType(ArrayType t, Type s) {
1198 if (s.hasTag(ARRAY)) {
1199 if (t.elemtype.isPrimitive())
1200 return isSameType(t.elemtype, elemtype(s));
1201 else
1202 return isSubtypeNoCapture(t.elemtype, elemtype(s));
1203 }
1204
1205 if (s.hasTag(CLASS)) {
1206 Name sname = s.tsym.getQualifiedName();
1207 return sname == names.java_lang_Object
1208 || sname == names.java_lang_Cloneable
1209 || sname == names.java_io_Serializable;
1210 }
1211
1212 return false;
1213 }
1214
1215 @Override
1216 public Boolean visitUndetVar(UndetVar t, Type s) {
1217 //todo: test against origin needed? or replace with substitution?
1218 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
1219 return true;
1220 } else if (s.hasTag(BOT)) {
1221 //if 's' is 'null' there's no instantiated type U for which
1222 //U <: s (but 'null' itself, which is not a valid type)
1223 return false;
1224 }
1225
1226 t.addBound(InferenceBound.UPPER, s, Types.this);
1227 return true;
1228 }
1229
1230 @Override
1231 public Boolean visitErrorType(ErrorType t, Type s) {
1232 return true;
1233 }
1234 };
1235
1236 /**
1237 * Is t a subtype of every type in given list `ts'?<br>
1238 * (not defined for Method and ForAll types)<br>
1239 * Allows unchecked conversions.
1240 */
1241 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
1242 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
1243 if (!isSubtypeUnchecked(t, l.head, warn))
1244 return false;
1245 return true;
1246 }
1247
1248 /**
1249 * Are corresponding elements of ts subtypes of ss? If lists are
1250 * of different length, return false.
1251 */
1252 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
1253 while (ts.tail != null && ss.tail != null
1254 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1255 isSubtype(ts.head, ss.head)) {
1256 ts = ts.tail;
1257 ss = ss.tail;
1258 }
1259 return ts.tail == null && ss.tail == null;
1260 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1261 }
1262
1263 /**
1264 * Are corresponding elements of ts subtypes of ss, allowing
1265 * unchecked conversions? If lists are of different length,
1266 * return false.
1267 **/
1268 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
1269 while (ts.tail != null && ss.tail != null
1270 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1271 isSubtypeUnchecked(ts.head, ss.head, warn)) {
1272 ts = ts.tail;
1273 ss = ss.tail;
1274 }
1275 return ts.tail == null && ss.tail == null;
1276 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1277 }
1278 // </editor-fold>
1279
1280 // <editor-fold defaultstate="collapsed" desc="isSuperType">
1281 /**
1282 * Is t a supertype of s?
1283 */
1284 public boolean isSuperType(Type t, Type s) {
1285 switch (t.getTag()) {
1286 case ERROR:
1287 return true;
1288 case UNDETVAR: {
1289 UndetVar undet = (UndetVar)t;
1290 if (t == s ||
1291 undet.qtype == s ||
1292 s.hasTag(ERROR) ||
1293 s.hasTag(BOT)) {
1294 return true;
1295 }
1296 undet.addBound(InferenceBound.LOWER, s, this);
1297 return true;
1298 }
1299 default:
1300 return isSubtype(s, t);
1301 }
1302 }
1303 // </editor-fold>
1304
1305 // <editor-fold defaultstate="collapsed" desc="isSameType">
1306 /**
1307 * Are corresponding elements of the lists the same type? If
1308 * lists are of different length, return false.
1309 */
1310 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
1311 while (ts.tail != null && ss.tail != null
1312 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1313 isSameType(ts.head, ss.head)) {
1314 ts = ts.tail;
1315 ss = ss.tail;
1316 }
1317 return ts.tail == null && ss.tail == null;
1318 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1319 }
1320
1321 /**
1322 * A polymorphic signature method (JLS 15.12.3) is a method that
1323 * (i) is declared in the java.lang.invoke.MethodHandle/VarHandle classes;
1324 * (ii) takes a single variable arity parameter;
1325 * (iii) whose declared type is Object[];
1326 * (iv) has any return type, Object signifying a polymorphic return type; and
1327 * (v) is native.
1328 */
1329 public boolean isSignaturePolymorphic(MethodSymbol msym) {
1330 List<Type> argtypes = msym.type.getParameterTypes();
1331 return (msym.flags_field & NATIVE) != 0 &&
1332 (msym.owner == syms.methodHandleType.tsym || msym.owner == syms.varHandleType.tsym) &&
1333 argtypes.length() == 1 &&
1334 argtypes.head.hasTag(TypeTag.ARRAY) &&
1335 ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym;
1336 }
1337
1338 /**
1339 * Is t the same type as s?
1340 */
1341 public boolean isSameType(Type t, Type s) {
1342 return isSameTypeVisitor.visit(t, s);
1343 }
1344 // where
1345
1346 /**
1347 * Type-equality relation - type variables are considered
1348 * equals if they share the same object identity.
1349 */
1350 TypeRelation isSameTypeVisitor = new TypeRelation() {
1351
1352 public Boolean visitType(Type t, Type s) {
1353 if (t.equalsIgnoreMetadata(s))
1354 return true;
1355
1356 if (s.isPartial())
1357 return visit(s, t);
1358
1359 switch (t.getTag()) {
1360 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1361 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
1362 return t.hasTag(s.getTag());
1363 case TYPEVAR: {
1364 if (s.hasTag(TYPEVAR)) {
1365 //type-substitution does not preserve type-var types
1366 //check that type var symbols and bounds are indeed the same
1367 return t == s;
1368 }
1369 else {
1370 //special case for s == ? super X, where upper(s) = u
1371 //check that u == t, where u has been set by Type.withTypeVar
1372 return s.isSuperBound() &&
1373 !s.isExtendsBound() &&
1374 visit(t, wildUpperBound(s));
1375 }
1376 }
1377 default:
1378 throw new AssertionError("isSameType " + t.getTag());
1379 }
1380 }
1381
1382 @Override
1383 public Boolean visitWildcardType(WildcardType t, Type s) {
1384 if (!s.hasTag(WILDCARD)) {
1385 return false;
1386 } else {
1387 WildcardType t2 = (WildcardType)s;
1388 return (t.kind == t2.kind || (t.isExtendsBound() && s.isExtendsBound())) &&
1389 isSameType(t.type, t2.type);
1390 }
1391 }
1392
1393 @Override
1394 public Boolean visitClassType(ClassType t, Type s) {
1395 if (t == s)
1396 return true;
1397
1398 if (s.isPartial())
1399 return visit(s, t);
1400
1401 if (s.isSuperBound() && !s.isExtendsBound())
1402 return visit(t, wildUpperBound(s)) && visit(t, wildLowerBound(s));
1403
1404 if (t.isCompound() && s.isCompound()) {
1405 if (!visit(supertype(t), supertype(s)))
1406 return false;
1407
1408 Map<Symbol,Type> tMap = new HashMap<>();
1409 for (Type ti : interfaces(t)) {
1410 if (tMap.containsKey(ti)) {
1411 throw new AssertionError("Malformed intersection");
1412 }
1413 tMap.put(ti.tsym, ti);
1414 }
1415 for (Type si : interfaces(s)) {
1416 if (!tMap.containsKey(si.tsym))
1417 return false;
1418 Type ti = tMap.remove(si.tsym);
1419 if (!visit(ti, si))
1420 return false;
1421 }
1422 return tMap.isEmpty();
1423 }
1424 return t.tsym == s.tsym
1425 && visit(t.getEnclosingType(), s.getEnclosingType())
1426 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
1427 }
1428
1429 @Override
1430 public Boolean visitArrayType(ArrayType t, Type s) {
1431 if (t == s)
1432 return true;
1433
1434 if (s.isPartial())
1435 return visit(s, t);
1436
1437 return s.hasTag(ARRAY)
1438 && containsTypeEquivalent(t.elemtype, elemtype(s));
1439 }
1440
1441 @Override
1442 public Boolean visitMethodType(MethodType t, Type s) {
1443 // isSameType for methods does not take thrown
1444 // exceptions into account!
1445 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
1446 }
1447
1448 @Override
1449 public Boolean visitPackageType(PackageType t, Type s) {
1450 return t == s;
1451 }
1452
1453 @Override
1454 public Boolean visitForAll(ForAll t, Type s) {
1455 if (!s.hasTag(FORALL)) {
1456 return false;
1457 }
1458
1459 ForAll forAll = (ForAll)s;
1460 return hasSameBounds(t, forAll)
1461 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1462 }
1463
1464 @Override
1465 public Boolean visitUndetVar(UndetVar t, Type s) {
1466 if (s.hasTag(WILDCARD)) {
1467 // FIXME, this might be leftovers from before capture conversion
1468 return false;
1469 }
1470
1471 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
1472 return true;
1473 }
1474
1475 t.addBound(InferenceBound.EQ, s, Types.this);
1476
1477 return true;
1478 }
1479
1480 @Override
1481 public Boolean visitErrorType(ErrorType t, Type s) {
1482 return true;
1483 }
1484 };
1485
1486 // </editor-fold>
1487
1488 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1489 public boolean containedBy(Type t, Type s) {
1490 switch (t.getTag()) {
1491 case UNDETVAR:
1492 if (s.hasTag(WILDCARD)) {
1493 UndetVar undetvar = (UndetVar)t;
1494 WildcardType wt = (WildcardType)s;
1495 switch(wt.kind) {
1496 case UNBOUND:
1497 break;
1498 case EXTENDS: {
1499 Type bound = wildUpperBound(s);
1500 undetvar.addBound(InferenceBound.UPPER, bound, this);
1501 break;
1502 }
1503 case SUPER: {
1504 Type bound = wildLowerBound(s);
1505 undetvar.addBound(InferenceBound.LOWER, bound, this);
1506 break;
1507 }
1508 }
1509 return true;
1510 } else {
1511 return isSameType(t, s);
1512 }
1513 case ERROR:
1514 return true;
1515 default:
1516 return containsType(s, t);
1517 }
1518 }
1519
1520 boolean containsType(List<Type> ts, List<Type> ss) {
1521 while (ts.nonEmpty() && ss.nonEmpty()
1522 && containsType(ts.head, ss.head)) {
1523 ts = ts.tail;
1524 ss = ss.tail;
1525 }
1526 return ts.isEmpty() && ss.isEmpty();
1527 }
1528
1529 /**
1530 * Check if t contains s.
1531 *
1532 * <p>T contains S if:
1533 *
1534 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1535 *
1536 * <p>This relation is only used by ClassType.isSubtype(), that
1537 * is,
1538 *
1539 * <p>{@code C<S> <: C<T> if T contains S.}
1540 *
1541 * <p>Because of F-bounds, this relation can lead to infinite
1542 * recursion. Thus we must somehow break that recursion. Notice
1543 * that containsType() is only called from ClassType.isSubtype().
1544 * Since the arguments have already been checked against their
1545 * bounds, we know:
1546 *
1547 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1548 *
1549 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1550 *
1551 * @param t a type
1552 * @param s a type
1553 */
1554 public boolean containsType(Type t, Type s) {
1555 return containsType.visit(t, s);
1556 }
1557 // where
1558 private TypeRelation containsType = new TypeRelation() {
1559
1560 public Boolean visitType(Type t, Type s) {
1561 if (s.isPartial())
1562 return containedBy(s, t);
1563 else
1564 return isSameType(t, s);
1565 }
1566
1567 // void debugContainsType(WildcardType t, Type s) {
1568 // System.err.println();
1569 // System.err.format(" does %s contain %s?%n", t, s);
1570 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1571 // wildUpperBound(s), s, t, wildUpperBound(t),
1572 // t.isSuperBound()
1573 // || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t)));
1574 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1575 // wildLowerBound(t), t, s, wildLowerBound(s),
1576 // t.isExtendsBound()
1577 // || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s)));
1578 // System.err.println();
1579 // }
1580
1581 @Override
1582 public Boolean visitWildcardType(WildcardType t, Type s) {
1583 if (s.isPartial())
1584 return containedBy(s, t);
1585 else {
1586 // debugContainsType(t, s);
1587 return isSameWildcard(t, s)
1588 || isCaptureOf(s, t)
1589 || ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))) &&
1590 (t.isSuperBound() || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t))));
1591 }
1592 }
1593
1594 @Override
1595 public Boolean visitUndetVar(UndetVar t, Type s) {
1596 if (!s.hasTag(WILDCARD)) {
1597 return isSameType(t, s);
1598 } else {
1599 return false;
1600 }
1601 }
1602
1603 @Override
1604 public Boolean visitErrorType(ErrorType t, Type s) {
1605 return true;
1606 }
1607 };
1608
1609 public boolean isCaptureOf(Type s, WildcardType t) {
1610 if (!s.hasTag(TYPEVAR) || !((TypeVar)s).isCaptured())
1611 return false;
1612 return isSameWildcard(t, ((CapturedType)s).wildcard);
1613 }
1614
1615 public boolean isSameWildcard(WildcardType t, Type s) {
1616 if (!s.hasTag(WILDCARD))
1617 return false;
1618 WildcardType w = (WildcardType)s;
1619 return w.kind == t.kind && w.type == t.type;
1620 }
1621
1622 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1623 while (ts.nonEmpty() && ss.nonEmpty()
1624 && containsTypeEquivalent(ts.head, ss.head)) {
1625 ts = ts.tail;
1626 ss = ss.tail;
1627 }
1628 return ts.isEmpty() && ss.isEmpty();
1629 }
1630 // </editor-fold>
1631
1632 // <editor-fold defaultstate="collapsed" desc="isCastable">
1633 public boolean isCastable(Type t, Type s) {
1634 return isCastable(t, s, noWarnings);
1635 }
1636
1637 /**
1638 * Is t castable to s?<br>
1639 * s is assumed to be an erased type.<br>
1640 * (not defined for Method and ForAll types).
1641 */
1642 public boolean isCastable(Type t, Type s, Warner warn) {
1643 // if same type
1644 if (t == s)
1645 return true;
1646 // if one of the types is primitive
1647 if (t.isPrimitive() != s.isPrimitive()) {
1648 t = skipTypeVars(t, false);
1649 return (isConvertible(t, s, warn)
1650 || (s.isPrimitive() &&
1651 isSubtype(boxedClass(s).type, t)));
1652 }
1653 boolean result;
1654 if (warn != warnStack.head) {
1655 try {
1656 warnStack = warnStack.prepend(warn);
1657 checkUnsafeVarargsConversion(t, s, warn);
1658 result = isCastable.visit(t,s);
1659 } finally {
1660 warnStack = warnStack.tail;
1661 }
1662 } else {
1663 result = isCastable.visit(t,s);
1664 }
1665 if (result && t.hasTag(CLASS) && t.tsym.kind.matches(Kinds.KindSelector.TYP)
1666 && s.hasTag(CLASS) && s.tsym.kind.matches(Kinds.KindSelector.TYP)
1667 && (t.tsym.isSealed() || s.tsym.isSealed())) {
1668 return (t.isCompound() || s.isCompound()) ?
1669 true :
1670 !areDisjoint((ClassSymbol)t.tsym, (ClassSymbol)s.tsym);
1671 }
1672 return result;
1673 }
1674 // where
1675 private boolean areDisjoint(ClassSymbol ts, ClassSymbol ss) {
1676 if (isSubtype(erasure(ts.type), erasure(ss.type))) {
1677 return false;
1678 }
1679 // if both are classes or both are interfaces, shortcut
1680 if (ts.isInterface() == ss.isInterface() && isSubtype(erasure(ss.type), erasure(ts.type))) {
1681 return false;
1682 }
1683 if (ts.isInterface() && !ss.isInterface()) {
1684 /* so ts is interface but ss is a class
1685 * an interface is disjoint from a class if the class is disjoint form the interface
1686 */
1687 return areDisjoint(ss, ts);
1688 }
1689 // a final class that is not subtype of ss is disjoint
1690 if (!ts.isInterface() && ts.isFinal()) {
1691 return true;
1692 }
1693 // if at least one is sealed
1694 if (ts.isSealed() || ss.isSealed()) {
1695 // permitted subtypes have to be disjoint with the other symbol
1696 ClassSymbol sealedOne = ts.isSealed() ? ts : ss;
1697 ClassSymbol other = sealedOne == ts ? ss : ts;
1698 return sealedOne.permitted.stream().allMatch(sym -> areDisjoint((ClassSymbol)sym, other));
1699 }
1700 return false;
1701 }
1702
1703 private TypeRelation isCastable = new TypeRelation() {
1704
1705 public Boolean visitType(Type t, Type s) {
1706 if (s.hasTag(ERROR) || t.hasTag(NONE))
1707 return true;
1708
1709 switch (t.getTag()) {
1710 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1711 case DOUBLE:
1712 return s.isNumeric();
1713 case BOOLEAN:
1714 return s.hasTag(BOOLEAN);
1715 case VOID:
1716 return false;
1717 case BOT:
1718 return isSubtype(t, s);
1719 default:
1720 throw new AssertionError();
1721 }
1722 }
1723
1724 @Override
1725 public Boolean visitWildcardType(WildcardType t, Type s) {
1726 return isCastable(wildUpperBound(t), s, warnStack.head);
1727 }
1728
1729 @Override
1730 public Boolean visitClassType(ClassType t, Type s) {
1731 if (s.hasTag(ERROR) || s.hasTag(BOT))
1732 return true;
1733
1734 if (s.hasTag(TYPEVAR)) {
1735 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1736 warnStack.head.warn(LintCategory.UNCHECKED);
1737 return true;
1738 } else {
1739 return false;
1740 }
1741 }
1742
1743 if (t.isCompound() || s.isCompound()) {
1744 return !t.isCompound() ?
1745 visitCompoundType((ClassType)s, t, true) :
1746 visitCompoundType(t, s, false);
1747 }
1748
1749 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) {
1750 boolean upcast;
1751 if ((upcast = isSubtype(erasure(t), erasure(s)))
1752 || isSubtype(erasure(s), erasure(t))) {
1753 if (!upcast && s.hasTag(ARRAY)) {
1754 if (!isReifiable(s))
1755 warnStack.head.warn(LintCategory.UNCHECKED);
1756 return true;
1757 } else if (s.isRaw()) {
1758 return true;
1759 } else if (t.isRaw()) {
1760 if (!isUnbounded(s))
1761 warnStack.head.warn(LintCategory.UNCHECKED);
1762 return true;
1763 }
1764 // Assume |a| <: |b|
1765 final Type a = upcast ? t : s;
1766 final Type b = upcast ? s : t;
1767 final boolean HIGH = true;
1768 final boolean LOW = false;
1769 final boolean DONT_REWRITE_TYPEVARS = false;
1770 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1771 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1772 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1773 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1774 Type lowSub = asSub(bLow, aLow.tsym);
1775 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1776 if (highSub == null) {
1777 final boolean REWRITE_TYPEVARS = true;
1778 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1779 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1780 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1781 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1782 lowSub = asSub(bLow, aLow.tsym);
1783 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1784 }
1785 if (highSub != null) {
1786 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1787 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1788 }
1789 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1790 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1791 && !disjointTypes(aLow.allparams(), highSub.allparams())
1792 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1793 if (upcast ? giveWarning(a, b) :
1794 giveWarning(b, a))
1795 warnStack.head.warn(LintCategory.UNCHECKED);
1796 return true;
1797 }
1798 }
1799 if (isReifiable(s))
1800 return isSubtypeUnchecked(a, b);
1801 else
1802 return isSubtypeUnchecked(a, b, warnStack.head);
1803 }
1804
1805 // Sidecast
1806 if (s.hasTag(CLASS)) {
1807 if ((s.tsym.flags() & INTERFACE) != 0) {
1808 return ((t.tsym.flags() & FINAL) == 0)
1809 ? sideCast(t, s, warnStack.head)
1810 : sideCastFinal(t, s, warnStack.head);
1811 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1812 return ((s.tsym.flags() & FINAL) == 0)
1813 ? sideCast(t, s, warnStack.head)
1814 : sideCastFinal(t, s, warnStack.head);
1815 } else {
1816 // unrelated class types
1817 return false;
1818 }
1819 }
1820 }
1821 return false;
1822 }
1823
1824 boolean visitCompoundType(ClassType ct, Type s, boolean reverse) {
1825 Warner warn = noWarnings;
1826 for (Type c : directSupertypes(ct)) {
1827 warn.clear();
1828 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1829 return false;
1830 }
1831 if (warn.hasLint(LintCategory.UNCHECKED))
1832 warnStack.head.warn(LintCategory.UNCHECKED);
1833 return true;
1834 }
1835
1836 @Override
1837 public Boolean visitArrayType(ArrayType t, Type s) {
1838 switch (s.getTag()) {
1839 case ERROR:
1840 case BOT:
1841 return true;
1842 case TYPEVAR:
1843 if (isCastable(s, t, noWarnings)) {
1844 warnStack.head.warn(LintCategory.UNCHECKED);
1845 return true;
1846 } else {
1847 return false;
1848 }
1849 case CLASS:
1850 return isSubtype(t, s);
1851 case ARRAY:
1852 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1853 return elemtype(t).hasTag(elemtype(s).getTag());
1854 } else {
1855 return visit(elemtype(t), elemtype(s));
1856 }
1857 default:
1858 return false;
1859 }
1860 }
1861
1862 @Override
1863 public Boolean visitTypeVar(TypeVar t, Type s) {
1864 switch (s.getTag()) {
1865 case ERROR:
1866 case BOT:
1867 return true;
1868 case TYPEVAR:
1869 if (isSubtype(t, s)) {
1870 return true;
1871 } else if (isCastable(t.getUpperBound(), s, noWarnings)) {
1872 warnStack.head.warn(LintCategory.UNCHECKED);
1873 return true;
1874 } else {
1875 return false;
1876 }
1877 default:
1878 return isCastable(t.getUpperBound(), s, warnStack.head);
1879 }
1880 }
1881
1882 @Override
1883 public Boolean visitErrorType(ErrorType t, Type s) {
1884 return true;
1885 }
1886 };
1887 // </editor-fold>
1888
1889 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1890 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1891 while (ts.tail != null && ss.tail != null) {
1892 if (disjointType(ts.head, ss.head)) return true;
1893 ts = ts.tail;
1894 ss = ss.tail;
1895 }
1896 return false;
1897 }
1898
1899 /**
1900 * Two types or wildcards are considered disjoint if it can be
1901 * proven that no type can be contained in both. It is
1902 * conservative in that it is allowed to say that two types are
1903 * not disjoint, even though they actually are.
1904 *
1905 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1906 * {@code X} and {@code Y} are not disjoint.
1907 */
1908 public boolean disjointType(Type t, Type s) {
1909 return disjointType.visit(t, s);
1910 }
1911 // where
1912 private TypeRelation disjointType = new TypeRelation() {
1913
1914 private Set<TypePair> cache = new HashSet<>();
1915
1916 @Override
1917 public Boolean visitType(Type t, Type s) {
1918 if (s.hasTag(WILDCARD))
1919 return visit(s, t);
1920 else
1921 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1922 }
1923
1924 private boolean isCastableRecursive(Type t, Type s) {
1925 TypePair pair = new TypePair(t, s);
1926 if (cache.add(pair)) {
1927 try {
1928 return Types.this.isCastable(t, s);
1929 } finally {
1930 cache.remove(pair);
1931 }
1932 } else {
1933 return true;
1934 }
1935 }
1936
1937 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1938 TypePair pair = new TypePair(t, s);
1939 if (cache.add(pair)) {
1940 try {
1941 return Types.this.notSoftSubtype(t, s);
1942 } finally {
1943 cache.remove(pair);
1944 }
1945 } else {
1946 return false;
1947 }
1948 }
1949
1950 @Override
1951 public Boolean visitWildcardType(WildcardType t, Type s) {
1952 if (t.isUnbound())
1953 return false;
1954
1955 if (!s.hasTag(WILDCARD)) {
1956 if (t.isExtendsBound())
1957 return notSoftSubtypeRecursive(s, t.type);
1958 else
1959 return notSoftSubtypeRecursive(t.type, s);
1960 }
1961
1962 if (s.isUnbound())
1963 return false;
1964
1965 if (t.isExtendsBound()) {
1966 if (s.isExtendsBound())
1967 return !isCastableRecursive(t.type, wildUpperBound(s));
1968 else if (s.isSuperBound())
1969 return notSoftSubtypeRecursive(wildLowerBound(s), t.type);
1970 } else if (t.isSuperBound()) {
1971 if (s.isExtendsBound())
1972 return notSoftSubtypeRecursive(t.type, wildUpperBound(s));
1973 }
1974 return false;
1975 }
1976 };
1977 // </editor-fold>
1978
1979 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds">
1980 public List<Type> cvarLowerBounds(List<Type> ts) {
1981 return ts.map(cvarLowerBoundMapping);
1982 }
1983 private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() {
1984 @Override
1985 public Type visitCapturedType(CapturedType t, Void _unused) {
1986 return cvarLowerBound(t);
1987 }
1988 };
1989 // </editor-fold>
1990
1991 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1992 /**
1993 * This relation answers the question: is impossible that
1994 * something of type `t' can be a subtype of `s'? This is
1995 * different from the question "is `t' not a subtype of `s'?"
1996 * when type variables are involved: Integer is not a subtype of T
1997 * where {@code <T extends Number>} but it is not true that Integer cannot
1998 * possibly be a subtype of T.
1999 */
2000 public boolean notSoftSubtype(Type t, Type s) {
2001 if (t == s) return false;
2002 if (t.hasTag(TYPEVAR)) {
2003 TypeVar tv = (TypeVar) t;
2004 return !isCastable(tv.getUpperBound(),
2005 relaxBound(s),
2006 noWarnings);
2007 }
2008 if (!s.hasTag(WILDCARD))
2009 s = cvarUpperBound(s);
2010
2011 return !isSubtype(t, relaxBound(s));
2012 }
2013
2014 private Type relaxBound(Type t) {
2015 return (t.hasTag(TYPEVAR)) ?
2016 rewriteQuantifiers(skipTypeVars(t, false), true, true) :
2017 t;
2018 }
2019 // </editor-fold>
2020
2021 // <editor-fold defaultstate="collapsed" desc="isReifiable">
2022 public boolean isReifiable(Type t) {
2023 return isReifiable.visit(t);
2024 }
2025 // where
2026 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
2027
2028 public Boolean visitType(Type t, Void ignored) {
2029 return true;
2030 }
2031
2032 @Override
2033 public Boolean visitClassType(ClassType t, Void ignored) {
2034 if (t.isCompound())
2035 return false;
2036 else {
2037 if (!t.isParameterized())
2038 return true;
2039
2040 for (Type param : t.allparams()) {
2041 if (!param.isUnbound())
2042 return false;
2043 }
2044 return true;
2045 }
2046 }
2047
2048 @Override
2049 public Boolean visitArrayType(ArrayType t, Void ignored) {
2050 return visit(t.elemtype);
2051 }
2052
2053 @Override
2054 public Boolean visitTypeVar(TypeVar t, Void ignored) {
2055 return false;
2056 }
2057 };
2058 // </editor-fold>
2059
2060 // <editor-fold defaultstate="collapsed" desc="Array Utils">
2061 public boolean isArray(Type t) {
2062 while (t.hasTag(WILDCARD))
2063 t = wildUpperBound(t);
2064 return t.hasTag(ARRAY);
2065 }
2066
2067 /**
2068 * The element type of an array.
2069 */
2070 public Type elemtype(Type t) {
2071 switch (t.getTag()) {
2072 case WILDCARD:
2073 return elemtype(wildUpperBound(t));
2074 case ARRAY:
2075 return ((ArrayType)t).elemtype;
2076 case FORALL:
2077 return elemtype(((ForAll)t).qtype);
2078 case ERROR:
2079 return t;
2080 default:
2081 return null;
2082 }
2083 }
2084
2085 public Type elemtypeOrType(Type t) {
2086 Type elemtype = elemtype(t);
2087 return elemtype != null ?
2088 elemtype :
2089 t;
2090 }
2091
2092 /**
2093 * Mapping to take element type of an arraytype
2094 */
2095 private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() {
2096 @Override
2097 public Type visitArrayType(ArrayType t, Void _unused) {
2098 return t.elemtype;
2099 }
2100
2101 @Override
2102 public Type visitTypeVar(TypeVar t, Void _unused) {
2103 return visit(skipTypeVars(t, false));
2104 }
2105 };
2106
2107 /**
2108 * The number of dimensions of an array type.
2109 */
2110 public int dimensions(Type t) {
2111 int result = 0;
2112 while (t.hasTag(ARRAY)) {
2113 result++;
2114 t = elemtype(t);
2115 }
2116 return result;
2117 }
2118
2119 /**
2120 * Returns an ArrayType with the component type t
2121 *
2122 * @param t The component type of the ArrayType
2123 * @return the ArrayType for the given component
2124 */
2125 public ArrayType makeArrayType(Type t) {
2126 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) {
2127 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
2128 }
2129 return new ArrayType(t, syms.arrayClass);
2130 }
2131 // </editor-fold>
2132
2133 // <editor-fold defaultstate="collapsed" desc="asSuper">
2134 /**
2135 * Return the (most specific) base type of t that starts with the
2136 * given symbol. If none exists, return null.
2137 *
2138 * Caveat Emptor: Since javac represents the class of all arrays with a singleton
2139 * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant,
2140 * this method could yield surprising answers when invoked on arrays. For example when
2141 * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null.
2142 *
2143 * @param t a type
2144 * @param sym a symbol
2145 */
2146 public Type asSuper(Type t, Symbol sym) {
2147 /* Some examples:
2148 *
2149 * (Enum<E>, Comparable) => Comparable<E>
2150 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind>
2151 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree
2152 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) =>
2153 * Iterable<capture#160 of ? extends c.s.s.d.DocTree>
2154 */
2155 if (sym.type == syms.objectType) { //optimization
2156 return syms.objectType;
2157 }
2158 return asSuper.visit(t, sym);
2159 }
2160 // where
2161 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
2162
2163 private Set<Symbol> seenTypes = new HashSet<>();
2164
2165 public Type visitType(Type t, Symbol sym) {
2166 return null;
2167 }
2168
2169 @Override
2170 public Type visitClassType(ClassType t, Symbol sym) {
2171 if (t.tsym == sym)
2172 return t;
2173
2174 Symbol c = t.tsym;
2175 if (!seenTypes.add(c)) {
2176 return null;
2177 }
2178 try {
2179 Type st = supertype(t);
2180 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) {
2181 Type x = asSuper(st, sym);
2182 if (x != null)
2183 return x;
2184 }
2185 if ((sym.flags() & INTERFACE) != 0) {
2186 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
2187 if (!l.head.hasTag(ERROR)) {
2188 Type x = asSuper(l.head, sym);
2189 if (x != null)
2190 return x;
2191 }
2192 }
2193 }
2194 return null;
2195 } finally {
2196 seenTypes.remove(c);
2197 }
2198 }
2199
2200 @Override
2201 public Type visitArrayType(ArrayType t, Symbol sym) {
2202 return isSubtype(t, sym.type) ? sym.type : null;
2203 }
2204
2205 @Override
2206 public Type visitTypeVar(TypeVar t, Symbol sym) {
2207 if (t.tsym == sym)
2208 return t;
2209 else
2210 return asSuper(t.getUpperBound(), sym);
2211 }
2212
2213 @Override
2214 public Type visitErrorType(ErrorType t, Symbol sym) {
2215 return t;
2216 }
2217 };
2218
2219 /**
2220 * Return the base type of t or any of its outer types that starts
2221 * with the given symbol. If none exists, return null.
2222 *
2223 * @param t a type
2224 * @param sym a symbol
2225 */
2226 public Type asOuterSuper(Type t, Symbol sym) {
2227 switch (t.getTag()) {
2228 case CLASS:
2229 do {
2230 Type s = asSuper(t, sym);
2231 if (s != null) return s;
2232 t = t.getEnclosingType();
2233 } while (t.hasTag(CLASS));
2234 return null;
2235 case ARRAY:
2236 return isSubtype(t, sym.type) ? sym.type : null;
2237 case TYPEVAR:
2238 return asSuper(t, sym);
2239 case ERROR:
2240 return t;
2241 default:
2242 return null;
2243 }
2244 }
2245
2246 /**
2247 * Return the base type of t or any of its enclosing types that
2248 * starts with the given symbol. If none exists, return null.
2249 *
2250 * @param t a type
2251 * @param sym a symbol
2252 */
2253 public Type asEnclosingSuper(Type t, Symbol sym) {
2254 switch (t.getTag()) {
2255 case CLASS:
2256 do {
2257 Type s = asSuper(t, sym);
2258 if (s != null) return s;
2259 Type outer = t.getEnclosingType();
2260 t = (outer.hasTag(CLASS)) ? outer :
2261 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
2262 Type.noType;
2263 } while (t.hasTag(CLASS));
2264 return null;
2265 case ARRAY:
2266 return isSubtype(t, sym.type) ? sym.type : null;
2267 case TYPEVAR:
2268 return asSuper(t, sym);
2269 case ERROR:
2270 return t;
2271 default:
2272 return null;
2273 }
2274 }
2275 // </editor-fold>
2276
2277 // <editor-fold defaultstate="collapsed" desc="memberType">
2278 /**
2279 * The type of given symbol, seen as a member of t.
2280 *
2281 * @param t a type
2282 * @param sym a symbol
2283 */
2284 public Type memberType(Type t, Symbol sym) {
2285 return (sym.flags() & STATIC) != 0
2286 ? sym.type
2287 : memberType.visit(t, sym);
2288 }
2289 // where
2290 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
2291
2292 public Type visitType(Type t, Symbol sym) {
2293 return sym.type;
2294 }
2295
2296 @Override
2297 public Type visitWildcardType(WildcardType t, Symbol sym) {
2298 return memberType(wildUpperBound(t), sym);
2299 }
2300
2301 @Override
2302 public Type visitClassType(ClassType t, Symbol sym) {
2303 Symbol owner = sym.owner;
2304 long flags = sym.flags();
2305 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
2306 Type base = asOuterSuper(t, owner);
2307 //if t is an intersection type T = CT & I1 & I2 ... & In
2308 //its supertypes CT, I1, ... In might contain wildcards
2309 //so we need to go through capture conversion
2310 base = t.isCompound() ? capture(base) : base;
2311 if (base != null) {
2312 List<Type> ownerParams = owner.type.allparams();
2313 List<Type> baseParams = base.allparams();
2314 if (ownerParams.nonEmpty()) {
2315 if (baseParams.isEmpty()) {
2316 // then base is a raw type
2317 return erasure(sym.type);
2318 } else {
2319 return subst(sym.type, ownerParams, baseParams);
2320 }
2321 }
2322 }
2323 }
2324 return sym.type;
2325 }
2326
2327 @Override
2328 public Type visitTypeVar(TypeVar t, Symbol sym) {
2329 return memberType(t.getUpperBound(), sym);
2330 }
2331
2332 @Override
2333 public Type visitErrorType(ErrorType t, Symbol sym) {
2334 return t;
2335 }
2336 };
2337 // </editor-fold>
2338
2339 // <editor-fold defaultstate="collapsed" desc="isAssignable">
2340 public boolean isAssignable(Type t, Type s) {
2341 return isAssignable(t, s, noWarnings);
2342 }
2343
2344 /**
2345 * Is t assignable to s?<br>
2346 * Equivalent to subtype except for constant values and raw
2347 * types.<br>
2348 * (not defined for Method and ForAll types)
2349 */
2350 public boolean isAssignable(Type t, Type s, Warner warn) {
2351 if (t.hasTag(ERROR))
2352 return true;
2353 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) {
2354 int value = ((Number)t.constValue()).intValue();
2355 switch (s.getTag()) {
2356 case BYTE:
2357 case CHAR:
2358 case SHORT:
2359 case INT:
2360 if (s.getTag().checkRange(value))
2361 return true;
2362 break;
2363 case CLASS:
2364 switch (unboxedType(s).getTag()) {
2365 case BYTE:
2366 case CHAR:
2367 case SHORT:
2368 return isAssignable(t, unboxedType(s), warn);
2369 }
2370 break;
2371 }
2372 }
2373 return isConvertible(t, s, warn);
2374 }
2375 // </editor-fold>
2376
2377 // <editor-fold defaultstate="collapsed" desc="erasure">
2378 /**
2379 * The erasure of t {@code |t|} -- the type that results when all
2380 * type parameters in t are deleted.
2381 */
2382 public Type erasure(Type t) {
2383 return eraseNotNeeded(t) ? t : erasure(t, false);
2384 }
2385 //where
2386 private boolean eraseNotNeeded(Type t) {
2387 // We don't want to erase primitive types and String type as that
2388 // operation is idempotent. Also, erasing these could result in loss
2389 // of information such as constant values attached to such types.
2390 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2391 }
2392
2393 private Type erasure(Type t, boolean recurse) {
2394 if (t.isPrimitive()) {
2395 return t; /* fast special case */
2396 } else {
2397 Type out = erasure.visit(t, recurse);
2398 return out;
2399 }
2400 }
2401 // where
2402 private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() {
2403 private Type combineMetadata(final Type s,
2404 final Type t) {
2405 if (t.getMetadata() != TypeMetadata.EMPTY) {
2406 switch (s.getKind()) {
2407 case OTHER:
2408 case UNION:
2409 case INTERSECTION:
2410 case PACKAGE:
2411 case EXECUTABLE:
2412 case NONE:
2413 case VOID:
2414 case ERROR:
2415 return s;
2416 default: return s.cloneWithMetadata(s.getMetadata().without(Kind.ANNOTATIONS));
2417 }
2418 } else {
2419 return s;
2420 }
2421 }
2422
2423 public Type visitType(Type t, Boolean recurse) {
2424 if (t.isPrimitive())
2425 return t; /*fast special case*/
2426 else {
2427 //other cases already handled
2428 return combineMetadata(t, t);
2429 }
2430 }
2431
2432 @Override
2433 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2434 Type erased = erasure(wildUpperBound(t), recurse);
2435 return combineMetadata(erased, t);
2436 }
2437
2438 @Override
2439 public Type visitClassType(ClassType t, Boolean recurse) {
2440 Type erased = t.tsym.erasure(Types.this);
2441 if (recurse) {
2442 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym,
2443 t.getMetadata().without(Kind.ANNOTATIONS));
2444 return erased;
2445 } else {
2446 return combineMetadata(erased, t);
2447 }
2448 }
2449
2450 @Override
2451 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2452 Type erased = erasure(t.getUpperBound(), recurse);
2453 return combineMetadata(erased, t);
2454 }
2455 };
2456
2457 public List<Type> erasure(List<Type> ts) {
2458 return erasure.visit(ts, false);
2459 }
2460
2461 public Type erasureRecursive(Type t) {
2462 return erasure(t, true);
2463 }
2464
2465 public List<Type> erasureRecursive(List<Type> ts) {
2466 return erasure.visit(ts, true);
2467 }
2468 // </editor-fold>
2469
2470 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType">
2471 /**
2472 * Make an intersection type from non-empty list of types. The list should be ordered according to
2473 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion.
2474 * Hence, this version of makeIntersectionType may not be called during a classfile read.
2475 *
2476 * @param bounds the types from which the intersection type is formed
2477 */
2478 public IntersectionClassType makeIntersectionType(List<Type> bounds) {
2479 return makeIntersectionType(bounds, bounds.head.tsym.isInterface());
2480 }
2481
2482 /**
2483 * Make an intersection type from non-empty list of types. The list should be ordered according to
2484 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as
2485 * an extra parameter indicates as to whether all bounds are interfaces - in which case the
2486 * supertype is implicitly assumed to be 'Object'.
2487 *
2488 * @param bounds the types from which the intersection type is formed
2489 * @param allInterfaces are all bounds interface types?
2490 */
2491 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) {
2492 Assert.check(bounds.nonEmpty());
2493 Type firstExplicitBound = bounds.head;
2494 if (allInterfaces) {
2495 bounds = bounds.prepend(syms.objectType);
2496 }
2497 ClassSymbol bc =
2498 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2499 Type.moreInfo
2500 ? names.fromString(bounds.toString())
2501 : names.empty,
2502 null,
2503 syms.noSymbol);
2504 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces);
2505 bc.type = intersectionType;
2506 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
2507 syms.objectType : // error condition, recover
2508 erasure(firstExplicitBound);
2509 bc.members_field = WriteableScope.create(bc);
2510 return intersectionType;
2511 }
2512 // </editor-fold>
2513
2514 // <editor-fold defaultstate="collapsed" desc="supertype">
2515 public Type supertype(Type t) {
2516 return supertype.visit(t);
2517 }
2518 // where
2519 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2520
2521 public Type visitType(Type t, Void ignored) {
2522 // A note on wildcards: there is no good way to
2523 // determine a supertype for a lower-bounded wildcard.
2524 return Type.noType;
2525 }
2526
2527 @Override
2528 public Type visitClassType(ClassType t, Void ignored) {
2529 if (t.supertype_field == null) {
2530 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2531 // An interface has no superclass; its supertype is Object.
2532 if (t.isInterface())
2533 supertype = ((ClassType)t.tsym.type).supertype_field;
2534 if (t.supertype_field == null) {
2535 List<Type> actuals = classBound(t).allparams();
2536 List<Type> formals = t.tsym.type.allparams();
2537 if (t.hasErasedSupertypes()) {
2538 t.supertype_field = erasureRecursive(supertype);
2539 } else if (formals.nonEmpty()) {
2540 t.supertype_field = subst(supertype, formals, actuals);
2541 }
2542 else {
2543 t.supertype_field = supertype;
2544 }
2545 }
2546 }
2547 return t.supertype_field;
2548 }
2549
2550 /**
2551 * The supertype is always a class type. If the type
2552 * variable's bounds start with a class type, this is also
2553 * the supertype. Otherwise, the supertype is
2554 * java.lang.Object.
2555 */
2556 @Override
2557 public Type visitTypeVar(TypeVar t, Void ignored) {
2558 if (t.getUpperBound().hasTag(TYPEVAR) ||
2559 (!t.getUpperBound().isCompound() && !t.getUpperBound().isInterface())) {
2560 return t.getUpperBound();
2561 } else {
2562 return supertype(t.getUpperBound());
2563 }
2564 }
2565
2566 @Override
2567 public Type visitArrayType(ArrayType t, Void ignored) {
2568 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2569 return arraySuperType();
2570 else
2571 return new ArrayType(supertype(t.elemtype), t.tsym);
2572 }
2573
2574 @Override
2575 public Type visitErrorType(ErrorType t, Void ignored) {
2576 return Type.noType;
2577 }
2578 };
2579 // </editor-fold>
2580
2581 // <editor-fold defaultstate="collapsed" desc="interfaces">
2582 /**
2583 * Return the interfaces implemented by this class.
2584 */
2585 public List<Type> interfaces(Type t) {
2586 return interfaces.visit(t);
2587 }
2588 // where
2589 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2590
2591 public List<Type> visitType(Type t, Void ignored) {
2592 return List.nil();
2593 }
2594
2595 @Override
2596 public List<Type> visitClassType(ClassType t, Void ignored) {
2597 if (t.interfaces_field == null) {
2598 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2599 if (t.interfaces_field == null) {
2600 // If t.interfaces_field is null, then t must
2601 // be a parameterized type (not to be confused
2602 // with a generic type declaration).
2603 // Terminology:
2604 // Parameterized type: List<String>
2605 // Generic type declaration: class List<E> { ... }
2606 // So t corresponds to List<String> and
2607 // t.tsym.type corresponds to List<E>.
2608 // The reason t must be parameterized type is
2609 // that completion will happen as a side
2610 // effect of calling
2611 // ClassSymbol.getInterfaces. Since
2612 // t.interfaces_field is null after
2613 // completion, we can assume that t is not the
2614 // type of a class/interface declaration.
2615 Assert.check(t != t.tsym.type, t);
2616 List<Type> actuals = t.allparams();
2617 List<Type> formals = t.tsym.type.allparams();
2618 if (t.hasErasedSupertypes()) {
2619 t.interfaces_field = erasureRecursive(interfaces);
2620 } else if (formals.nonEmpty()) {
2621 t.interfaces_field = subst(interfaces, formals, actuals);
2622 }
2623 else {
2624 t.interfaces_field = interfaces;
2625 }
2626 }
2627 }
2628 return t.interfaces_field;
2629 }
2630
2631 @Override
2632 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2633 if (t.getUpperBound().isCompound())
2634 return interfaces(t.getUpperBound());
2635
2636 if (t.getUpperBound().isInterface())
2637 return List.of(t.getUpperBound());
2638
2639 return List.nil();
2640 }
2641 };
2642
2643 public List<Type> directSupertypes(Type t) {
2644 return directSupertypes.visit(t);
2645 }
2646 // where
2647 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() {
2648
2649 public List<Type> visitType(final Type type, final Void ignored) {
2650 if (!type.isIntersection()) {
2651 final Type sup = supertype(type);
2652 return (sup == Type.noType || sup == type || sup == null)
2653 ? interfaces(type)
2654 : interfaces(type).prepend(sup);
2655 } else {
2656 return ((IntersectionClassType)type).getExplicitComponents();
2657 }
2658 }
2659 };
2660
2661 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2662 for (Type i2 : interfaces(origin.type)) {
2663 if (isym == i2.tsym) return true;
2664 }
2665 return false;
2666 }
2667 // </editor-fold>
2668
2669 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2670 Map<Type,Boolean> isDerivedRawCache = new HashMap<>();
2671
2672 public boolean isDerivedRaw(Type t) {
2673 Boolean result = isDerivedRawCache.get(t);
2674 if (result == null) {
2675 result = isDerivedRawInternal(t);
2676 isDerivedRawCache.put(t, result);
2677 }
2678 return result;
2679 }
2680
2681 public boolean isDerivedRawInternal(Type t) {
2682 if (t.isErroneous())
2683 return false;
2684 return
2685 t.isRaw() ||
2686 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) ||
2687 isDerivedRaw(interfaces(t));
2688 }
2689
2690 public boolean isDerivedRaw(List<Type> ts) {
2691 List<Type> l = ts;
2692 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2693 return l.nonEmpty();
2694 }
2695 // </editor-fold>
2696
2697 // <editor-fold defaultstate="collapsed" desc="setBounds">
2698 /**
2699 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly,
2700 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise
2701 * the supertype is simply left null (in this case, the supertype is assumed to be the head of
2702 * the bound list passed as second argument). Note that this check might cause a symbol completion.
2703 * Hence, this version of setBounds may not be called during a classfile read.
2704 *
2705 * @param t a type variable
2706 * @param bounds the bounds, must be nonempty
2707 */
2708 public void setBounds(TypeVar t, List<Type> bounds) {
2709 setBounds(t, bounds, bounds.head.tsym.isInterface());
2710 }
2711
2712 /**
2713 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds.
2714 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds
2715 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'.
2716 *
2717 * @param t a type variable
2718 * @param bounds the bounds, must be nonempty
2719 * @param allInterfaces are all bounds interface types?
2720 */
2721 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2722 t.setUpperBound( bounds.tail.isEmpty() ?
2723 bounds.head :
2724 makeIntersectionType(bounds, allInterfaces) );
2725 t.rank_field = -1;
2726 }
2727 // </editor-fold>
2728
2729 // <editor-fold defaultstate="collapsed" desc="getBounds">
2730 /**
2731 * Return list of bounds of the given type variable.
2732 */
2733 public List<Type> getBounds(TypeVar t) {
2734 if (t.getUpperBound().hasTag(NONE))
2735 return List.nil();
2736 else if (t.getUpperBound().isErroneous() || !t.getUpperBound().isCompound())
2737 return List.of(t.getUpperBound());
2738 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2739 return interfaces(t).prepend(supertype(t));
2740 else
2741 // No superclass was given in bounds.
2742 // In this case, supertype is Object, erasure is first interface.
2743 return interfaces(t);
2744 }
2745 // </editor-fold>
2746
2747 // <editor-fold defaultstate="collapsed" desc="classBound">
2748 /**
2749 * If the given type is a (possibly selected) type variable,
2750 * return the bounding class of this type, otherwise return the
2751 * type itself.
2752 */
2753 public Type classBound(Type t) {
2754 return classBound.visit(t);
2755 }
2756 // where
2757 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2758
2759 public Type visitType(Type t, Void ignored) {
2760 return t;
2761 }
2762
2763 @Override
2764 public Type visitClassType(ClassType t, Void ignored) {
2765 Type outer1 = classBound(t.getEnclosingType());
2766 if (outer1 != t.getEnclosingType())
2767 return new ClassType(outer1, t.getTypeArguments(), t.tsym,
2768 t.getMetadata());
2769 else
2770 return t;
2771 }
2772
2773 @Override
2774 public Type visitTypeVar(TypeVar t, Void ignored) {
2775 return classBound(supertype(t));
2776 }
2777
2778 @Override
2779 public Type visitErrorType(ErrorType t, Void ignored) {
2780 return t;
2781 }
2782 };
2783 // </editor-fold>
2784
2785 // <editor-fold defaultstate="collapsed" desc="subsignature / override equivalence">
2786 /**
2787 * Returns true iff the first signature is a <em>subsignature</em>
2788 * of the other. This is <b>not</b> an equivalence
2789 * relation.
2790 *
2791 * @jls 8.4.2 Method Signature
2792 * @see #overrideEquivalent(Type t, Type s)
2793 * @param t first signature (possibly raw).
2794 * @param s second signature (could be subjected to erasure).
2795 * @return true if t is a subsignature of s.
2796 */
2797 public boolean isSubSignature(Type t, Type s) {
2798 return hasSameArgs(t, s, true) || hasSameArgs(t, erasure(s), true);
2799 }
2800
2801 /**
2802 * Returns true iff these signatures are related by <em>override
2803 * equivalence</em>. This is the natural extension of
2804 * isSubSignature to an equivalence relation.
2805 *
2806 * @jls 8.4.2 Method Signature
2807 * @see #isSubSignature(Type t, Type s)
2808 * @param t a signature (possible raw, could be subjected to
2809 * erasure).
2810 * @param s a signature (possible raw, could be subjected to
2811 * erasure).
2812 * @return true if either argument is a subsignature of the other.
2813 */
2814 public boolean overrideEquivalent(Type t, Type s) {
2815 return hasSameArgs(t, s) ||
2816 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2817 }
2818
2819 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2820 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) {
2821 if (msym.overrides(sym, origin, Types.this, true)) {
2822 return true;
2823 }
2824 }
2825 return false;
2826 }
2827
2828 /**
2829 * This enum defines the strategy for implementing most specific return type check
2830 * during the most specific and functional interface checks.
2831 */
2832 public enum MostSpecificReturnCheck {
2833 /**
2834 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling
2835 * method type variables (if either method is generic) and (ii) subtyping should be replaced
2836 * by type-equivalence for primitives. This is essentially an inlined version of
2837 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been
2838 * replaced with a strict subtyping check.
2839 */
2840 BASIC() {
2841 @Override
2842 public boolean test(Type mt1, Type mt2, Types types) {
2843 List<Type> tvars = mt1.getTypeArguments();
2844 List<Type> svars = mt2.getTypeArguments();
2845 Type t = mt1.getReturnType();
2846 Type s = types.subst(mt2.getReturnType(), svars, tvars);
2847 return types.isSameType(t, s) ||
2848 !t.isPrimitive() &&
2849 !s.isPrimitive() &&
2850 types.isSubtype(t, s);
2851 }
2852 },
2853 /**
2854 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2.
2855 */
2856 RTS() {
2857 @Override
2858 public boolean test(Type mt1, Type mt2, Types types) {
2859 return types.returnTypeSubstitutable(mt1, mt2);
2860 }
2861 };
2862
2863 public abstract boolean test(Type mt1, Type mt2, Types types);
2864 }
2865
2866 /**
2867 * Merge multiple abstract methods. The preferred method is a method that is a subsignature
2868 * of all the other signatures and whose return type is more specific {@see MostSpecificReturnCheck}.
2869 * The resulting preferred method has a thrown clause that is the intersection of the merged
2870 * methods' clauses.
2871 */
2872 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) {
2873 //first check for preconditions
2874 boolean shouldErase = false;
2875 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes();
2876 for (Symbol s : ambiguousInOrder) {
2877 if ((s.flags() & ABSTRACT) == 0 ||
2878 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) {
2879 return Optional.empty();
2880 } else if (s.type.hasTag(FORALL)) {
2881 shouldErase = true;
2882 }
2883 }
2884 //then merge abstracts
2885 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) {
2886 outer: for (Symbol s : ambiguousInOrder) {
2887 Type mt = memberType(site, s);
2888 List<Type> allThrown = mt.getThrownTypes();
2889 for (Symbol s2 : ambiguousInOrder) {
2890 if (s != s2) {
2891 Type mt2 = memberType(site, s2);
2892 if (!isSubSignature(mt, mt2) ||
2893 !mostSpecificReturnCheck.test(mt, mt2, this)) {
2894 //ambiguity cannot be resolved
2895 continue outer;
2896 } else {
2897 List<Type> thrownTypes2 = mt2.getThrownTypes();
2898 if (!mt.hasTag(FORALL) && shouldErase) {
2899 thrownTypes2 = erasure(thrownTypes2);
2900 } else if (mt.hasTag(FORALL)) {
2901 //subsignature implies that if most specific is generic, then all other
2902 //methods are too
2903 Assert.check(mt2.hasTag(FORALL));
2904 // if both are generic methods, adjust thrown types ahead of intersection computation
2905 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments());
2906 }
2907 allThrown = chk.intersect(allThrown, thrownTypes2);
2908 }
2909 }
2910 }
2911 return (allThrown == mt.getThrownTypes()) ?
2912 Optional.of(s) :
2913 Optional.of(new MethodSymbol(
2914 s.flags(),
2915 s.name,
2916 createMethodTypeWithThrown(s.type, allThrown),
2917 s.owner) {
2918 @Override
2919 public Symbol baseSymbol() {
2920 return s;
2921 }
2922 });
2923 }
2924 }
2925 return Optional.empty();
2926 }
2927
2928 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2929 class ImplementationCache {
2930
2931 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>();
2932
2933 class Entry {
2934 final MethodSymbol cachedImpl;
2935 final Predicate<Symbol> implFilter;
2936 final boolean checkResult;
2937 final int prevMark;
2938
2939 public Entry(MethodSymbol cachedImpl,
2940 Predicate<Symbol> scopeFilter,
2941 boolean checkResult,
2942 int prevMark) {
2943 this.cachedImpl = cachedImpl;
2944 this.implFilter = scopeFilter;
2945 this.checkResult = checkResult;
2946 this.prevMark = prevMark;
2947 }
2948
2949 boolean matches(Predicate<Symbol> scopeFilter, boolean checkResult, int mark) {
2950 return this.implFilter == scopeFilter &&
2951 this.checkResult == checkResult &&
2952 this.prevMark == mark;
2953 }
2954 }
2955
2956 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2957 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2958 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2959 if (cache == null) {
2960 cache = new HashMap<>();
2961 _map.put(ms, new SoftReference<>(cache));
2962 }
2963 Entry e = cache.get(origin);
2964 CompoundScope members = membersClosure(origin.type, true);
2965 if (e == null ||
2966 !e.matches(implFilter, checkResult, members.getMark())) {
2967 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2968 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2969 return impl;
2970 }
2971 else {
2972 return e.cachedImpl;
2973 }
2974 }
2975
2976 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2977 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
2978 t = skipTypeVars(t, false);
2979 TypeSymbol c = t.tsym;
2980 Symbol bestSoFar = null;
2981 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) {
2982 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) {
2983 bestSoFar = sym;
2984 if ((sym.flags() & ABSTRACT) == 0) {
2985 //if concrete impl is found, exit immediately
2986 break;
2987 }
2988 }
2989 }
2990 if (bestSoFar != null) {
2991 //return either the (only) concrete implementation or the first abstract one
2992 return (MethodSymbol)bestSoFar;
2993 }
2994 }
2995 return null;
2996 }
2997 }
2998
2999 private ImplementationCache implCache = new ImplementationCache();
3000
3001 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
3002 return implCache.get(ms, origin, checkResult, implFilter);
3003 }
3004 // </editor-fold>
3005
3006 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
3007 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> {
3008
3009 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>();
3010
3011 Set<TypeSymbol> seenTypes = new HashSet<>();
3012
3013 class MembersScope extends CompoundScope {
3014
3015 CompoundScope scope;
3016
3017 public MembersScope(CompoundScope scope) {
3018 super(scope.owner);
3019 this.scope = scope;
3020 }
3021
3022 Predicate<Symbol> combine(Predicate<Symbol> sf) {
3023 return s -> !s.owner.isInterface() && (sf == null || sf.test(s));
3024 }
3025
3026 @Override
3027 public Iterable<Symbol> getSymbols(Predicate<Symbol> sf, LookupKind lookupKind) {
3028 return scope.getSymbols(combine(sf), lookupKind);
3029 }
3030
3031 @Override
3032 public Iterable<Symbol> getSymbolsByName(Name name, Predicate<Symbol> sf, LookupKind lookupKind) {
3033 return scope.getSymbolsByName(name, combine(sf), lookupKind);
3034 }
3035
3036 @Override
3037 public int getMark() {
3038 return scope.getMark();
3039 }
3040 }
3041
3042 CompoundScope nilScope;
3043
3044 /** members closure visitor methods **/
3045
3046 public CompoundScope visitType(Type t, Void _unused) {
3047 if (nilScope == null) {
3048 nilScope = new CompoundScope(syms.noSymbol);
3049 }
3050 return nilScope;
3051 }
3052
3053 @Override
3054 public CompoundScope visitClassType(ClassType t, Void _unused) {
3055 if (!seenTypes.add(t.tsym)) {
3056 //this is possible when an interface is implemented in multiple
3057 //superclasses, or when a class hierarchy is circular - in such
3058 //cases we don't need to recurse (empty scope is returned)
3059 return new CompoundScope(t.tsym);
3060 }
3061 try {
3062 seenTypes.add(t.tsym);
3063 ClassSymbol csym = (ClassSymbol)t.tsym;
3064 CompoundScope membersClosure = _map.get(csym);
3065 if (membersClosure == null) {
3066 membersClosure = new CompoundScope(csym);
3067 for (Type i : interfaces(t)) {
3068 membersClosure.prependSubScope(visit(i, null));
3069 }
3070 membersClosure.prependSubScope(visit(supertype(t), null));
3071 membersClosure.prependSubScope(csym.members());
3072 _map.put(csym, membersClosure);
3073 }
3074 return membersClosure;
3075 }
3076 finally {
3077 seenTypes.remove(t.tsym);
3078 }
3079 }
3080
3081 @Override
3082 public CompoundScope visitTypeVar(TypeVar t, Void _unused) {
3083 return visit(t.getUpperBound(), null);
3084 }
3085 }
3086
3087 private MembersClosureCache membersCache = new MembersClosureCache();
3088
3089 public CompoundScope membersClosure(Type site, boolean skipInterface) {
3090 CompoundScope cs = membersCache.visit(site, null);
3091 Assert.checkNonNull(cs, () -> "type " + site);
3092 return skipInterface ? membersCache.new MembersScope(cs) : cs;
3093 }
3094 // </editor-fold>
3095
3096
3097 /** Return first abstract member of class `sym'.
3098 */
3099 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) {
3100 try {
3101 return firstUnimplementedAbstractImpl(sym, sym);
3102 } catch (CompletionFailure ex) {
3103 chk.completionError(enter.getEnv(sym).tree.pos(), ex);
3104 return null;
3105 }
3106 }
3107 //where:
3108 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) {
3109 MethodSymbol undef = null;
3110 // Do not bother to search in classes that are not abstract,
3111 // since they cannot have abstract members.
3112 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
3113 Scope s = c.members();
3114 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
3115 if (sym.kind == MTH &&
3116 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
3117 MethodSymbol absmeth = (MethodSymbol)sym;
3118 MethodSymbol implmeth = absmeth.implementation(impl, this, true);
3119 if (implmeth == null || implmeth == absmeth) {
3120 //look for default implementations
3121 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head;
3122 if (prov != null && prov.overrides(absmeth, impl, this, true)) {
3123 implmeth = prov;
3124 }
3125 }
3126 if (implmeth == null || implmeth == absmeth) {
3127 undef = absmeth;
3128 break;
3129 }
3130 }
3131 }
3132 if (undef == null) {
3133 Type st = supertype(c.type);
3134 if (st.hasTag(CLASS))
3135 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym);
3136 }
3137 for (List<Type> l = interfaces(c.type);
3138 undef == null && l.nonEmpty();
3139 l = l.tail) {
3140 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym);
3141 }
3142 }
3143 return undef;
3144 }
3145
3146 public class CandidatesCache {
3147 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>();
3148
3149 class Entry {
3150 Type site;
3151 MethodSymbol msym;
3152
3153 Entry(Type site, MethodSymbol msym) {
3154 this.site = site;
3155 this.msym = msym;
3156 }
3157
3158 @Override
3159 public boolean equals(Object obj) {
3160 return (obj instanceof Entry entry)
3161 && entry.msym == msym
3162 && isSameType(site, entry.site);
3163 }
3164
3165 @Override
3166 public int hashCode() {
3167 return Types.this.hashCode(site) & ~msym.hashCode();
3168 }
3169 }
3170
3171 public List<MethodSymbol> get(Entry e) {
3172 return cache.get(e);
3173 }
3174
3175 public void put(Entry e, List<MethodSymbol> msymbols) {
3176 cache.put(e, msymbols);
3177 }
3178 }
3179
3180 public CandidatesCache candidatesCache = new CandidatesCache();
3181
3182 //where
3183 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
3184 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms);
3185 List<MethodSymbol> candidates = candidatesCache.get(e);
3186 if (candidates == null) {
3187 Predicate<Symbol> filter = new MethodFilter(ms, site);
3188 List<MethodSymbol> candidates2 = List.nil();
3189 for (Symbol s : membersClosure(site, false).getSymbols(filter)) {
3190 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
3191 return List.of((MethodSymbol)s);
3192 } else if (!candidates2.contains(s)) {
3193 candidates2 = candidates2.prepend((MethodSymbol)s);
3194 }
3195 }
3196 candidates = prune(candidates2);
3197 candidatesCache.put(e, candidates);
3198 }
3199 return candidates;
3200 }
3201
3202 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
3203 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>();
3204 for (MethodSymbol m1 : methods) {
3205 boolean isMin_m1 = true;
3206 for (MethodSymbol m2 : methods) {
3207 if (m1 == m2) continue;
3208 if (m2.owner != m1.owner &&
3209 asSuper(m2.owner.type, m1.owner) != null) {
3210 isMin_m1 = false;
3211 break;
3212 }
3213 }
3214 if (isMin_m1)
3215 methodsMin.append(m1);
3216 }
3217 return methodsMin.toList();
3218 }
3219 // where
3220 private class MethodFilter implements Predicate<Symbol> {
3221
3222 Symbol msym;
3223 Type site;
3224
3225 MethodFilter(Symbol msym, Type site) {
3226 this.msym = msym;
3227 this.site = site;
3228 }
3229
3230 @Override
3231 public boolean test(Symbol s) {
3232 return s.kind == MTH &&
3233 s.name == msym.name &&
3234 (s.flags() & SYNTHETIC) == 0 &&
3235 s.isInheritedIn(site.tsym, Types.this) &&
3236 overrideEquivalent(memberType(site, s), memberType(site, msym));
3237 }
3238 }
3239 // </editor-fold>
3240
3241 /**
3242 * Does t have the same arguments as s? It is assumed that both
3243 * types are (possibly polymorphic) method types. Monomorphic
3244 * method types "have the same arguments", if their argument lists
3245 * are equal. Polymorphic method types "have the same arguments",
3246 * if they have the same arguments after renaming all type
3247 * variables of one to corresponding type variables in the other,
3248 * where correspondence is by position in the type parameter list.
3249 */
3250 public boolean hasSameArgs(Type t, Type s) {
3251 return hasSameArgs(t, s, true);
3252 }
3253
3254 public boolean hasSameArgs(Type t, Type s, boolean strict) {
3255 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
3256 }
3257
3258 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
3259 return hasSameArgs.visit(t, s);
3260 }
3261 // where
3262 private class HasSameArgs extends TypeRelation {
3263
3264 boolean strict;
3265
3266 public HasSameArgs(boolean strict) {
3267 this.strict = strict;
3268 }
3269
3270 public Boolean visitType(Type t, Type s) {
3271 throw new AssertionError();
3272 }
3273
3274 @Override
3275 public Boolean visitMethodType(MethodType t, Type s) {
3276 return s.hasTag(METHOD)
3277 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
3278 }
3279
3280 @Override
3281 public Boolean visitForAll(ForAll t, Type s) {
3282 if (!s.hasTag(FORALL))
3283 return strict ? false : visitMethodType(t.asMethodType(), s);
3284
3285 ForAll forAll = (ForAll)s;
3286 return hasSameBounds(t, forAll)
3287 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
3288 }
3289
3290 @Override
3291 public Boolean visitErrorType(ErrorType t, Type s) {
3292 return false;
3293 }
3294 }
3295
3296 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
3297 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
3298
3299 // </editor-fold>
3300
3301 // <editor-fold defaultstate="collapsed" desc="subst">
3302 public List<Type> subst(List<Type> ts,
3303 List<Type> from,
3304 List<Type> to) {
3305 return ts.map(new Subst(from, to));
3306 }
3307
3308 /**
3309 * Substitute all occurrences of a type in `from' with the
3310 * corresponding type in `to' in 't'. Match lists `from' and `to'
3311 * from the right: If lists have different length, discard leading
3312 * elements of the longer list.
3313 */
3314 public Type subst(Type t, List<Type> from, List<Type> to) {
3315 return t.map(new Subst(from, to));
3316 }
3317
3318 private class Subst extends StructuralTypeMapping<Void> {
3319 List<Type> from;
3320 List<Type> to;
3321
3322 public Subst(List<Type> from, List<Type> to) {
3323 int fromLength = from.length();
3324 int toLength = to.length();
3325 while (fromLength > toLength) {
3326 fromLength--;
3327 from = from.tail;
3328 }
3329 while (fromLength < toLength) {
3330 toLength--;
3331 to = to.tail;
3332 }
3333 this.from = from;
3334 this.to = to;
3335 }
3336
3337 @Override
3338 public Type visitTypeVar(TypeVar t, Void ignored) {
3339 for (List<Type> from = this.from, to = this.to;
3340 from.nonEmpty();
3341 from = from.tail, to = to.tail) {
3342 if (t.equalsIgnoreMetadata(from.head)) {
3343 return to.head.withTypeVar(t);
3344 }
3345 }
3346 return t;
3347 }
3348
3349 @Override
3350 public Type visitClassType(ClassType t, Void ignored) {
3351 if (!t.isCompound()) {
3352 return super.visitClassType(t, ignored);
3353 } else {
3354 Type st = visit(supertype(t));
3355 List<Type> is = visit(interfaces(t), ignored);
3356 if (st == supertype(t) && is == interfaces(t))
3357 return t;
3358 else
3359 return makeIntersectionType(is.prepend(st));
3360 }
3361 }
3362
3363 @Override
3364 public Type visitWildcardType(WildcardType t, Void ignored) {
3365 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored);
3366 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) {
3367 t2.type = wildUpperBound(t2.type);
3368 }
3369 return t2;
3370 }
3371
3372 @Override
3373 public Type visitForAll(ForAll t, Void ignored) {
3374 if (Type.containsAny(to, t.tvars)) {
3375 //perform alpha-renaming of free-variables in 't'
3376 //if 'to' types contain variables that are free in 't'
3377 List<Type> freevars = newInstances(t.tvars);
3378 t = new ForAll(freevars,
3379 Types.this.subst(t.qtype, t.tvars, freevars));
3380 }
3381 List<Type> tvars1 = substBounds(t.tvars, from, to);
3382 Type qtype1 = visit(t.qtype);
3383 if (tvars1 == t.tvars && qtype1 == t.qtype) {
3384 return t;
3385 } else if (tvars1 == t.tvars) {
3386 return new ForAll(tvars1, qtype1) {
3387 @Override
3388 public boolean needsStripping() {
3389 return true;
3390 }
3391 };
3392 } else {
3393 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) {
3394 @Override
3395 public boolean needsStripping() {
3396 return true;
3397 }
3398 };
3399 }
3400 }
3401 }
3402
3403 public List<Type> substBounds(List<Type> tvars,
3404 List<Type> from,
3405 List<Type> to) {
3406 if (tvars.isEmpty())
3407 return tvars;
3408 ListBuffer<Type> newBoundsBuf = new ListBuffer<>();
3409 boolean changed = false;
3410 // calculate new bounds
3411 for (Type t : tvars) {
3412 TypeVar tv = (TypeVar) t;
3413 Type bound = subst(tv.getUpperBound(), from, to);
3414 if (bound != tv.getUpperBound())
3415 changed = true;
3416 newBoundsBuf.append(bound);
3417 }
3418 if (!changed)
3419 return tvars;
3420 ListBuffer<Type> newTvars = new ListBuffer<>();
3421 // create new type variables without bounds
3422 for (Type t : tvars) {
3423 newTvars.append(new TypeVar(t.tsym, null, syms.botType,
3424 t.getMetadata()));
3425 }
3426 // the new bounds should use the new type variables in place
3427 // of the old
3428 List<Type> newBounds = newBoundsBuf.toList();
3429 from = tvars;
3430 to = newTvars.toList();
3431 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
3432 newBounds.head = subst(newBounds.head, from, to);
3433 }
3434 newBounds = newBoundsBuf.toList();
3435 // set the bounds of new type variables to the new bounds
3436 for (Type t : newTvars.toList()) {
3437 TypeVar tv = (TypeVar) t;
3438 tv.setUpperBound( newBounds.head );
3439 newBounds = newBounds.tail;
3440 }
3441 return newTvars.toList();
3442 }
3443
3444 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
3445 Type bound1 = subst(t.getUpperBound(), from, to);
3446 if (bound1 == t.getUpperBound())
3447 return t;
3448 else {
3449 // create new type variable without bounds
3450 TypeVar tv = new TypeVar(t.tsym, null, syms.botType,
3451 t.getMetadata());
3452 // the new bound should use the new type variable in place
3453 // of the old
3454 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) );
3455 return tv;
3456 }
3457 }
3458 // </editor-fold>
3459
3460 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
3461 /**
3462 * Does t have the same bounds for quantified variables as s?
3463 */
3464 public boolean hasSameBounds(ForAll t, ForAll s) {
3465 List<Type> l1 = t.tvars;
3466 List<Type> l2 = s.tvars;
3467 while (l1.nonEmpty() && l2.nonEmpty() &&
3468 isSameType(l1.head.getUpperBound(),
3469 subst(l2.head.getUpperBound(),
3470 s.tvars,
3471 t.tvars))) {
3472 l1 = l1.tail;
3473 l2 = l2.tail;
3474 }
3475 return l1.isEmpty() && l2.isEmpty();
3476 }
3477 // </editor-fold>
3478
3479 // <editor-fold defaultstate="collapsed" desc="newInstances">
3480 /** Create new vector of type variables from list of variables
3481 * changing all recursive bounds from old to new list.
3482 */
3483 public List<Type> newInstances(List<Type> tvars) {
3484 List<Type> tvars1 = tvars.map(newInstanceFun);
3485 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
3486 TypeVar tv = (TypeVar) l.head;
3487 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) );
3488 }
3489 return tvars1;
3490 }
3491 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() {
3492 @Override
3493 public TypeVar visitTypeVar(TypeVar t, Void _unused) {
3494 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata());
3495 }
3496 };
3497 // </editor-fold>
3498
3499 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
3500 return original.accept(methodWithParameters, newParams);
3501 }
3502 // where
3503 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
3504 public Type visitType(Type t, List<Type> newParams) {
3505 throw new IllegalArgumentException("Not a method type: " + t);
3506 }
3507 public Type visitMethodType(MethodType t, List<Type> newParams) {
3508 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
3509 }
3510 public Type visitForAll(ForAll t, List<Type> newParams) {
3511 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
3512 }
3513 };
3514
3515 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
3516 return original.accept(methodWithThrown, newThrown);
3517 }
3518 // where
3519 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
3520 public Type visitType(Type t, List<Type> newThrown) {
3521 throw new IllegalArgumentException("Not a method type: " + t);
3522 }
3523 public Type visitMethodType(MethodType t, List<Type> newThrown) {
3524 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
3525 }
3526 public Type visitForAll(ForAll t, List<Type> newThrown) {
3527 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
3528 }
3529 };
3530
3531 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
3532 return original.accept(methodWithReturn, newReturn);
3533 }
3534 // where
3535 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
3536 public Type visitType(Type t, Type newReturn) {
3537 throw new IllegalArgumentException("Not a method type: " + t);
3538 }
3539 public Type visitMethodType(MethodType t, Type newReturn) {
3540 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) {
3541 @Override
3542 public Type baseType() {
3543 return t;
3544 }
3545 };
3546 }
3547 public Type visitForAll(ForAll t, Type newReturn) {
3548 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) {
3549 @Override
3550 public Type baseType() {
3551 return t;
3552 }
3553 };
3554 }
3555 };
3556
3557 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3558 public Type createErrorType(Type originalType) {
3559 return new ErrorType(originalType, syms.errSymbol);
3560 }
3561
3562 public Type createErrorType(ClassSymbol c, Type originalType) {
3563 return new ErrorType(c, originalType);
3564 }
3565
3566 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3567 return new ErrorType(name, container, originalType);
3568 }
3569 // </editor-fold>
3570
3571 // <editor-fold defaultstate="collapsed" desc="rank">
3572 /**
3573 * The rank of a class is the length of the longest path between
3574 * the class and java.lang.Object in the class inheritance
3575 * graph. Undefined for all but reference types.
3576 */
3577 public int rank(Type t) {
3578 switch(t.getTag()) {
3579 case CLASS: {
3580 ClassType cls = (ClassType)t;
3581 if (cls.rank_field < 0) {
3582 Name fullname = cls.tsym.getQualifiedName();
3583 if (fullname == names.java_lang_Object)
3584 cls.rank_field = 0;
3585 else {
3586 int r = rank(supertype(cls));
3587 for (List<Type> l = interfaces(cls);
3588 l.nonEmpty();
3589 l = l.tail) {
3590 if (rank(l.head) > r)
3591 r = rank(l.head);
3592 }
3593 cls.rank_field = r + 1;
3594 }
3595 }
3596 return cls.rank_field;
3597 }
3598 case TYPEVAR: {
3599 TypeVar tvar = (TypeVar)t;
3600 if (tvar.rank_field < 0) {
3601 int r = rank(supertype(tvar));
3602 for (List<Type> l = interfaces(tvar);
3603 l.nonEmpty();
3604 l = l.tail) {
3605 if (rank(l.head) > r) r = rank(l.head);
3606 }
3607 tvar.rank_field = r + 1;
3608 }
3609 return tvar.rank_field;
3610 }
3611 case ERROR:
3612 case NONE:
3613 return 0;
3614 default:
3615 throw new AssertionError();
3616 }
3617 }
3618 // </editor-fold>
3619
3620 /**
3621 * Helper method for generating a string representation of a given type
3622 * accordingly to a given locale
3623 */
3624 public String toString(Type t, Locale locale) {
3625 return Printer.createStandardPrinter(messages).visit(t, locale);
3626 }
3627
3628 /**
3629 * Helper method for generating a string representation of a given type
3630 * accordingly to a given locale
3631 */
3632 public String toString(Symbol t, Locale locale) {
3633 return Printer.createStandardPrinter(messages).visit(t, locale);
3634 }
3635
3636 // <editor-fold defaultstate="collapsed" desc="toString">
3637 /**
3638 * This toString is slightly more descriptive than the one on Type.
3639 *
3640 * @deprecated Types.toString(Type t, Locale l) provides better support
3641 * for localization
3642 */
3643 @Deprecated
3644 public String toString(Type t) {
3645 if (t.hasTag(FORALL)) {
3646 ForAll forAll = (ForAll)t;
3647 return typaramsString(forAll.tvars) + forAll.qtype;
3648 }
3649 return "" + t;
3650 }
3651 // where
3652 private String typaramsString(List<Type> tvars) {
3653 StringBuilder s = new StringBuilder();
3654 s.append('<');
3655 boolean first = true;
3656 for (Type t : tvars) {
3657 if (!first) s.append(", ");
3658 first = false;
3659 appendTyparamString(((TypeVar)t), s);
3660 }
3661 s.append('>');
3662 return s.toString();
3663 }
3664 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3665 buf.append(t);
3666 if (t.getUpperBound() == null ||
3667 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object)
3668 return;
3669 buf.append(" extends "); // Java syntax; no need for i18n
3670 Type bound = t.getUpperBound();
3671 if (!bound.isCompound()) {
3672 buf.append(bound);
3673 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3674 buf.append(supertype(t));
3675 for (Type intf : interfaces(t)) {
3676 buf.append('&');
3677 buf.append(intf);
3678 }
3679 } else {
3680 // No superclass was given in bounds.
3681 // In this case, supertype is Object, erasure is first interface.
3682 boolean first = true;
3683 for (Type intf : interfaces(t)) {
3684 if (!first) buf.append('&');
3685 first = false;
3686 buf.append(intf);
3687 }
3688 }
3689 }
3690 // </editor-fold>
3691
3692 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3693 /**
3694 * A cache for closures.
3695 *
3696 * <p>A closure is a list of all the supertypes and interfaces of
3697 * a class or interface type, ordered by ClassSymbol.precedes
3698 * (that is, subclasses come first, arbitrary but fixed
3699 * otherwise).
3700 */
3701 private Map<Type,List<Type>> closureCache = new HashMap<>();
3702
3703 /**
3704 * Returns the closure of a class or interface type.
3705 */
3706 public List<Type> closure(Type t) {
3707 List<Type> cl = closureCache.get(t);
3708 if (cl == null) {
3709 Type st = supertype(t);
3710 if (!t.isCompound()) {
3711 if (st.hasTag(CLASS)) {
3712 cl = insert(closure(st), t);
3713 } else if (st.hasTag(TYPEVAR)) {
3714 cl = closure(st).prepend(t);
3715 } else {
3716 cl = List.of(t);
3717 }
3718 } else {
3719 cl = closure(supertype(t));
3720 }
3721 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3722 cl = union(cl, closure(l.head));
3723 closureCache.put(t, cl);
3724 }
3725 return cl;
3726 }
3727
3728 /**
3729 * Collect types into a new closure (using a @code{ClosureHolder})
3730 */
3731 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3732 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip),
3733 ClosureHolder::add,
3734 ClosureHolder::merge,
3735 ClosureHolder::closure);
3736 }
3737 //where
3738 class ClosureHolder {
3739 List<Type> closure;
3740 final boolean minClosure;
3741 final BiPredicate<Type, Type> shouldSkip;
3742
3743 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3744 this.closure = List.nil();
3745 this.minClosure = minClosure;
3746 this.shouldSkip = shouldSkip;
3747 }
3748
3749 void add(Type type) {
3750 closure = insert(closure, type, shouldSkip);
3751 }
3752
3753 ClosureHolder merge(ClosureHolder other) {
3754 closure = union(closure, other.closure, shouldSkip);
3755 return this;
3756 }
3757
3758 List<Type> closure() {
3759 return minClosure ? closureMin(closure) : closure;
3760 }
3761 }
3762
3763 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym;
3764
3765 /**
3766 * Insert a type in a closure
3767 */
3768 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) {
3769 if (cl.isEmpty()) {
3770 return cl.prepend(t);
3771 } else if (shouldSkip.test(t, cl.head)) {
3772 return cl;
3773 } else if (t.tsym.precedes(cl.head.tsym, this)) {
3774 return cl.prepend(t);
3775 } else {
3776 // t comes after head, or the two are unrelated
3777 return insert(cl.tail, t, shouldSkip).prepend(cl.head);
3778 }
3779 }
3780
3781 public List<Type> insert(List<Type> cl, Type t) {
3782 return insert(cl, t, basicClosureSkip);
3783 }
3784
3785 /**
3786 * Form the union of two closures
3787 */
3788 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) {
3789 if (cl1.isEmpty()) {
3790 return cl2;
3791 } else if (cl2.isEmpty()) {
3792 return cl1;
3793 } else if (shouldSkip.test(cl1.head, cl2.head)) {
3794 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
3795 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3796 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
3797 } else {
3798 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
3799 }
3800 }
3801
3802 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3803 return union(cl1, cl2, basicClosureSkip);
3804 }
3805
3806 /**
3807 * Intersect two closures
3808 */
3809 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3810 if (cl1 == cl2)
3811 return cl1;
3812 if (cl1.isEmpty() || cl2.isEmpty())
3813 return List.nil();
3814 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3815 return intersect(cl1.tail, cl2);
3816 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3817 return intersect(cl1, cl2.tail);
3818 if (isSameType(cl1.head, cl2.head))
3819 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3820 if (cl1.head.tsym == cl2.head.tsym &&
3821 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) {
3822 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3823 Type merge = merge(cl1.head,cl2.head);
3824 return intersect(cl1.tail, cl2.tail).prepend(merge);
3825 }
3826 if (cl1.head.isRaw() || cl2.head.isRaw())
3827 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3828 }
3829 return intersect(cl1.tail, cl2.tail);
3830 }
3831 // where
3832 class TypePair {
3833 final Type t1;
3834 final Type t2;;
3835
3836 TypePair(Type t1, Type t2) {
3837 this.t1 = t1;
3838 this.t2 = t2;
3839 }
3840 @Override
3841 public int hashCode() {
3842 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3843 }
3844 @Override
3845 public boolean equals(Object obj) {
3846 return (obj instanceof TypePair typePair)
3847 && isSameType(t1, typePair.t1)
3848 && isSameType(t2, typePair.t2);
3849 }
3850 }
3851 Set<TypePair> mergeCache = new HashSet<>();
3852 private Type merge(Type c1, Type c2) {
3853 ClassType class1 = (ClassType) c1;
3854 List<Type> act1 = class1.getTypeArguments();
3855 ClassType class2 = (ClassType) c2;
3856 List<Type> act2 = class2.getTypeArguments();
3857 ListBuffer<Type> merged = new ListBuffer<>();
3858 List<Type> typarams = class1.tsym.type.getTypeArguments();
3859
3860 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3861 if (containsType(act1.head, act2.head)) {
3862 merged.append(act1.head);
3863 } else if (containsType(act2.head, act1.head)) {
3864 merged.append(act2.head);
3865 } else {
3866 TypePair pair = new TypePair(c1, c2);
3867 Type m;
3868 if (mergeCache.add(pair)) {
3869 m = new WildcardType(lub(wildUpperBound(act1.head),
3870 wildUpperBound(act2.head)),
3871 BoundKind.EXTENDS,
3872 syms.boundClass);
3873 mergeCache.remove(pair);
3874 } else {
3875 m = new WildcardType(syms.objectType,
3876 BoundKind.UNBOUND,
3877 syms.boundClass);
3878 }
3879 merged.append(m.withTypeVar(typarams.head));
3880 }
3881 act1 = act1.tail;
3882 act2 = act2.tail;
3883 typarams = typarams.tail;
3884 }
3885 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3886 // There is no spec detailing how type annotations are to
3887 // be inherited. So set it to noAnnotations for now
3888 return new ClassType(class1.getEnclosingType(), merged.toList(),
3889 class1.tsym);
3890 }
3891
3892 /**
3893 * Return the minimum type of a closure, a compound type if no
3894 * unique minimum exists.
3895 */
3896 private Type compoundMin(List<Type> cl) {
3897 if (cl.isEmpty()) return syms.objectType;
3898 List<Type> compound = closureMin(cl);
3899 if (compound.isEmpty())
3900 return null;
3901 else if (compound.tail.isEmpty())
3902 return compound.head;
3903 else
3904 return makeIntersectionType(compound);
3905 }
3906
3907 /**
3908 * Return the minimum types of a closure, suitable for computing
3909 * compoundMin or glb.
3910 */
3911 private List<Type> closureMin(List<Type> cl) {
3912 ListBuffer<Type> classes = new ListBuffer<>();
3913 ListBuffer<Type> interfaces = new ListBuffer<>();
3914 Set<Type> toSkip = new HashSet<>();
3915 while (!cl.isEmpty()) {
3916 Type current = cl.head;
3917 boolean keep = !toSkip.contains(current);
3918 if (keep && current.hasTag(TYPEVAR)) {
3919 // skip lower-bounded variables with a subtype in cl.tail
3920 for (Type t : cl.tail) {
3921 if (isSubtypeNoCapture(t, current)) {
3922 keep = false;
3923 break;
3924 }
3925 }
3926 }
3927 if (keep) {
3928 if (current.isInterface())
3929 interfaces.append(current);
3930 else
3931 classes.append(current);
3932 for (Type t : cl.tail) {
3933 // skip supertypes of 'current' in cl.tail
3934 if (isSubtypeNoCapture(current, t))
3935 toSkip.add(t);
3936 }
3937 }
3938 cl = cl.tail;
3939 }
3940 return classes.appendList(interfaces).toList();
3941 }
3942
3943 /**
3944 * Return the least upper bound of list of types. if the lub does
3945 * not exist return null.
3946 */
3947 public Type lub(List<Type> ts) {
3948 return lub(ts.toArray(new Type[ts.length()]));
3949 }
3950
3951 /**
3952 * Return the least upper bound (lub) of set of types. If the lub
3953 * does not exist return the type of null (bottom).
3954 */
3955 public Type lub(Type... ts) {
3956 final int UNKNOWN_BOUND = 0;
3957 final int ARRAY_BOUND = 1;
3958 final int CLASS_BOUND = 2;
3959
3960 int[] kinds = new int[ts.length];
3961
3962 int boundkind = UNKNOWN_BOUND;
3963 for (int i = 0 ; i < ts.length ; i++) {
3964 Type t = ts[i];
3965 switch (t.getTag()) {
3966 case CLASS:
3967 boundkind |= kinds[i] = CLASS_BOUND;
3968 break;
3969 case ARRAY:
3970 boundkind |= kinds[i] = ARRAY_BOUND;
3971 break;
3972 case TYPEVAR:
3973 do {
3974 t = t.getUpperBound();
3975 } while (t.hasTag(TYPEVAR));
3976 if (t.hasTag(ARRAY)) {
3977 boundkind |= kinds[i] = ARRAY_BOUND;
3978 } else {
3979 boundkind |= kinds[i] = CLASS_BOUND;
3980 }
3981 break;
3982 default:
3983 kinds[i] = UNKNOWN_BOUND;
3984 if (t.isPrimitive())
3985 return syms.errType;
3986 }
3987 }
3988 switch (boundkind) {
3989 case 0:
3990 return syms.botType;
3991
3992 case ARRAY_BOUND:
3993 // calculate lub(A[], B[])
3994 Type[] elements = new Type[ts.length];
3995 for (int i = 0 ; i < ts.length ; i++) {
3996 Type elem = elements[i] = elemTypeFun.apply(ts[i]);
3997 if (elem.isPrimitive()) {
3998 // if a primitive type is found, then return
3999 // arraySuperType unless all the types are the
4000 // same
4001 Type first = ts[0];
4002 for (int j = 1 ; j < ts.length ; j++) {
4003 if (!isSameType(first, ts[j])) {
4004 // lub(int[], B[]) is Cloneable & Serializable
4005 return arraySuperType();
4006 }
4007 }
4008 // all the array types are the same, return one
4009 // lub(int[], int[]) is int[]
4010 return first;
4011 }
4012 }
4013 // lub(A[], B[]) is lub(A, B)[]
4014 return new ArrayType(lub(elements), syms.arrayClass);
4015
4016 case CLASS_BOUND:
4017 // calculate lub(A, B)
4018 int startIdx = 0;
4019 for (int i = 0; i < ts.length ; i++) {
4020 Type t = ts[i];
4021 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) {
4022 break;
4023 } else {
4024 startIdx++;
4025 }
4026 }
4027 Assert.check(startIdx < ts.length);
4028 //step 1 - compute erased candidate set (EC)
4029 List<Type> cl = erasedSupertypes(ts[startIdx]);
4030 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4031 Type t = ts[i];
4032 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
4033 cl = intersect(cl, erasedSupertypes(t));
4034 }
4035 //step 2 - compute minimal erased candidate set (MEC)
4036 List<Type> mec = closureMin(cl);
4037 //step 3 - for each element G in MEC, compute lci(Inv(G))
4038 List<Type> candidates = List.nil();
4039 for (Type erasedSupertype : mec) {
4040 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
4041 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4042 Type superType = asSuper(ts[i], erasedSupertype.tsym);
4043 lci = intersect(lci, superType != null ? List.of(superType) : List.nil());
4044 }
4045 candidates = candidates.appendList(lci);
4046 }
4047 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
4048 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
4049 return compoundMin(candidates);
4050
4051 default:
4052 // calculate lub(A, B[])
4053 List<Type> classes = List.of(arraySuperType());
4054 for (int i = 0 ; i < ts.length ; i++) {
4055 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays
4056 classes = classes.prepend(ts[i]);
4057 }
4058 // lub(A, B[]) is lub(A, arraySuperType)
4059 return lub(classes);
4060 }
4061 }
4062 // where
4063 List<Type> erasedSupertypes(Type t) {
4064 ListBuffer<Type> buf = new ListBuffer<>();
4065 for (Type sup : closure(t)) {
4066 if (sup.hasTag(TYPEVAR)) {
4067 buf.append(sup);
4068 } else {
4069 buf.append(erasure(sup));
4070 }
4071 }
4072 return buf.toList();
4073 }
4074
4075 private Type arraySuperType;
4076 private Type arraySuperType() {
4077 // initialized lazily to avoid problems during compiler startup
4078 if (arraySuperType == null) {
4079 // JLS 10.8: all arrays implement Cloneable and Serializable.
4080 arraySuperType = makeIntersectionType(List.of(syms.serializableType,
4081 syms.cloneableType), true);
4082 }
4083 return arraySuperType;
4084 }
4085 // </editor-fold>
4086
4087 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
4088 public Type glb(List<Type> ts) {
4089 Type t1 = ts.head;
4090 for (Type t2 : ts.tail) {
4091 if (t1.isErroneous())
4092 return t1;
4093 t1 = glb(t1, t2);
4094 }
4095 return t1;
4096 }
4097 //where
4098 public Type glb(Type t, Type s) {
4099 if (s == null)
4100 return t;
4101 else if (t.isPrimitive() || s.isPrimitive())
4102 return syms.errType;
4103 else if (isSubtypeNoCapture(t, s))
4104 return t;
4105 else if (isSubtypeNoCapture(s, t))
4106 return s;
4107
4108 List<Type> closure = union(closure(t), closure(s));
4109 return glbFlattened(closure, t);
4110 }
4111 //where
4112 /**
4113 * Perform glb for a list of non-primitive, non-error, non-compound types;
4114 * redundant elements are removed. Bounds should be ordered according to
4115 * {@link Symbol#precedes(TypeSymbol,Types)}.
4116 *
4117 * @param flatBounds List of type to glb
4118 * @param errT Original type to use if the result is an error type
4119 */
4120 private Type glbFlattened(List<Type> flatBounds, Type errT) {
4121 List<Type> bounds = closureMin(flatBounds);
4122
4123 if (bounds.isEmpty()) { // length == 0
4124 return syms.objectType;
4125 } else if (bounds.tail.isEmpty()) { // length == 1
4126 return bounds.head;
4127 } else { // length > 1
4128 int classCount = 0;
4129 List<Type> cvars = List.nil();
4130 List<Type> lowers = List.nil();
4131 for (Type bound : bounds) {
4132 if (!bound.isInterface()) {
4133 classCount++;
4134 Type lower = cvarLowerBound(bound);
4135 if (bound != lower && !lower.hasTag(BOT)) {
4136 cvars = cvars.append(bound);
4137 lowers = lowers.append(lower);
4138 }
4139 }
4140 }
4141 if (classCount > 1) {
4142 if (lowers.isEmpty()) {
4143 return createErrorType(errT);
4144 } else {
4145 // try again with lower bounds included instead of capture variables
4146 List<Type> newBounds = bounds.diff(cvars).appendList(lowers);
4147 return glb(newBounds);
4148 }
4149 }
4150 }
4151 return makeIntersectionType(bounds);
4152 }
4153 // </editor-fold>
4154
4155 // <editor-fold defaultstate="collapsed" desc="hashCode">
4156 /**
4157 * Compute a hash code on a type.
4158 */
4159 public int hashCode(Type t) {
4160 return hashCode(t, false);
4161 }
4162
4163 public int hashCode(Type t, boolean strict) {
4164 return strict ?
4165 hashCodeStrictVisitor.visit(t) :
4166 hashCodeVisitor.visit(t);
4167 }
4168 // where
4169 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor();
4170 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() {
4171 @Override
4172 public Integer visitTypeVar(TypeVar t, Void ignored) {
4173 return System.identityHashCode(t);
4174 }
4175 };
4176
4177 private static class HashCodeVisitor extends UnaryVisitor<Integer> {
4178 public Integer visitType(Type t, Void ignored) {
4179 return t.getTag().ordinal();
4180 }
4181
4182 @Override
4183 public Integer visitClassType(ClassType t, Void ignored) {
4184 int result = visit(t.getEnclosingType());
4185 result *= 127;
4186 result += t.tsym.flatName().hashCode();
4187 for (Type s : t.getTypeArguments()) {
4188 result *= 127;
4189 result += visit(s);
4190 }
4191 return result;
4192 }
4193
4194 @Override
4195 public Integer visitMethodType(MethodType t, Void ignored) {
4196 int h = METHOD.ordinal();
4197 for (List<Type> thisargs = t.argtypes;
4198 thisargs.tail != null;
4199 thisargs = thisargs.tail)
4200 h = (h << 5) + visit(thisargs.head);
4201 return (h << 5) + visit(t.restype);
4202 }
4203
4204 @Override
4205 public Integer visitWildcardType(WildcardType t, Void ignored) {
4206 int result = t.kind.hashCode();
4207 if (t.type != null) {
4208 result *= 127;
4209 result += visit(t.type);
4210 }
4211 return result;
4212 }
4213
4214 @Override
4215 public Integer visitArrayType(ArrayType t, Void ignored) {
4216 return visit(t.elemtype) + 12;
4217 }
4218
4219 @Override
4220 public Integer visitTypeVar(TypeVar t, Void ignored) {
4221 return System.identityHashCode(t);
4222 }
4223
4224 @Override
4225 public Integer visitUndetVar(UndetVar t, Void ignored) {
4226 return System.identityHashCode(t);
4227 }
4228
4229 @Override
4230 public Integer visitErrorType(ErrorType t, Void ignored) {
4231 return 0;
4232 }
4233 }
4234 // </editor-fold>
4235
4236 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
4237 /**
4238 * Does t have a result that is a subtype of the result type of s,
4239 * suitable for covariant returns? It is assumed that both types
4240 * are (possibly polymorphic) method types. Monomorphic method
4241 * types are handled in the obvious way. Polymorphic method types
4242 * require renaming all type variables of one to corresponding
4243 * type variables in the other, where correspondence is by
4244 * position in the type parameter list. */
4245 public boolean resultSubtype(Type t, Type s, Warner warner) {
4246 List<Type> tvars = t.getTypeArguments();
4247 List<Type> svars = s.getTypeArguments();
4248 Type tres = t.getReturnType();
4249 Type sres = subst(s.getReturnType(), svars, tvars);
4250 return covariantReturnType(tres, sres, warner);
4251 }
4252
4253 /**
4254 * Return-Type-Substitutable.
4255 * @jls 8.4.5 Method Result
4256 */
4257 public boolean returnTypeSubstitutable(Type r1, Type r2) {
4258 if (hasSameArgs(r1, r2))
4259 return resultSubtype(r1, r2, noWarnings);
4260 else
4261 return covariantReturnType(r1.getReturnType(),
4262 erasure(r2.getReturnType()),
4263 noWarnings);
4264 }
4265
4266 public boolean returnTypeSubstitutable(Type r1,
4267 Type r2, Type r2res,
4268 Warner warner) {
4269 if (isSameType(r1.getReturnType(), r2res))
4270 return true;
4271 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
4272 return false;
4273
4274 if (hasSameArgs(r1, r2))
4275 return covariantReturnType(r1.getReturnType(), r2res, warner);
4276 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
4277 return true;
4278 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
4279 return false;
4280 warner.warn(LintCategory.UNCHECKED);
4281 return true;
4282 }
4283
4284 /**
4285 * Is t an appropriate return type in an overrider for a
4286 * method that returns s?
4287 */
4288 public boolean covariantReturnType(Type t, Type s, Warner warner) {
4289 return
4290 isSameType(t, s) ||
4291 !t.isPrimitive() &&
4292 !s.isPrimitive() &&
4293 isAssignable(t, s, warner);
4294 }
4295 // </editor-fold>
4296
4297 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
4298 /**
4299 * Return the class that boxes the given primitive.
4300 */
4301 public ClassSymbol boxedClass(Type t) {
4302 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]);
4303 }
4304
4305 /**
4306 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
4307 */
4308 public Type boxedTypeOrType(Type t) {
4309 return t.isPrimitive() ?
4310 boxedClass(t).type :
4311 t;
4312 }
4313
4314 /**
4315 * Return the primitive type corresponding to a boxed type.
4316 */
4317 public Type unboxedType(Type t) {
4318 if (t.hasTag(ERROR))
4319 return Type.noType;
4320 for (int i=0; i<syms.boxedName.length; i++) {
4321 Name box = syms.boxedName[i];
4322 if (box != null &&
4323 asSuper(t, syms.enterClass(syms.java_base, box)) != null)
4324 return syms.typeOfTag[i];
4325 }
4326 return Type.noType;
4327 }
4328
4329 /**
4330 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
4331 */
4332 public Type unboxedTypeOrType(Type t) {
4333 Type unboxedType = unboxedType(t);
4334 return unboxedType.hasTag(NONE) ? t : unboxedType;
4335 }
4336 // </editor-fold>
4337
4338 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
4339 /*
4340 * JLS 5.1.10 Capture Conversion:
4341 *
4342 * Let G name a generic type declaration with n formal type
4343 * parameters A1 ... An with corresponding bounds U1 ... Un. There
4344 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
4345 * where, for 1 <= i <= n:
4346 *
4347 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
4348 * Si is a fresh type variable whose upper bound is
4349 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
4350 * type.
4351 *
4352 * + If Ti is a wildcard type argument of the form ? extends Bi,
4353 * then Si is a fresh type variable whose upper bound is
4354 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
4355 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
4356 * a compile-time error if for any two classes (not interfaces)
4357 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
4358 *
4359 * + If Ti is a wildcard type argument of the form ? super Bi,
4360 * then Si is a fresh type variable whose upper bound is
4361 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
4362 *
4363 * + Otherwise, Si = Ti.
4364 *
4365 * Capture conversion on any type other than a parameterized type
4366 * (4.5) acts as an identity conversion (5.1.1). Capture
4367 * conversions never require a special action at run time and
4368 * therefore never throw an exception at run time.
4369 *
4370 * Capture conversion is not applied recursively.
4371 */
4372 /**
4373 * Capture conversion as specified by the JLS.
4374 */
4375
4376 public List<Type> capture(List<Type> ts) {
4377 List<Type> buf = List.nil();
4378 for (Type t : ts) {
4379 buf = buf.prepend(capture(t));
4380 }
4381 return buf.reverse();
4382 }
4383
4384 public Type capture(Type t) {
4385 if (!t.hasTag(CLASS)) {
4386 return t;
4387 }
4388 if (t.getEnclosingType() != Type.noType) {
4389 Type capturedEncl = capture(t.getEnclosingType());
4390 if (capturedEncl != t.getEnclosingType()) {
4391 Type type1 = memberType(capturedEncl, t.tsym);
4392 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
4393 }
4394 }
4395 ClassType cls = (ClassType)t;
4396 if (cls.isRaw() || !cls.isParameterized())
4397 return cls;
4398
4399 ClassType G = (ClassType)cls.asElement().asType();
4400 List<Type> A = G.getTypeArguments();
4401 List<Type> T = cls.getTypeArguments();
4402 List<Type> S = freshTypeVariables(T);
4403
4404 List<Type> currentA = A;
4405 List<Type> currentT = T;
4406 List<Type> currentS = S;
4407 boolean captured = false;
4408 while (!currentA.isEmpty() &&
4409 !currentT.isEmpty() &&
4410 !currentS.isEmpty()) {
4411 if (currentS.head != currentT.head) {
4412 captured = true;
4413 WildcardType Ti = (WildcardType)currentT.head;
4414 Type Ui = currentA.head.getUpperBound();
4415 CapturedType Si = (CapturedType)currentS.head;
4416 if (Ui == null)
4417 Ui = syms.objectType;
4418 switch (Ti.kind) {
4419 case UNBOUND:
4420 Si.setUpperBound( subst(Ui, A, S) );
4421 Si.lower = syms.botType;
4422 break;
4423 case EXTENDS:
4424 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) );
4425 Si.lower = syms.botType;
4426 break;
4427 case SUPER:
4428 Si.setUpperBound( subst(Ui, A, S) );
4429 Si.lower = Ti.getSuperBound();
4430 break;
4431 }
4432 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound();
4433 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower;
4434 if (!Si.getUpperBound().hasTag(ERROR) &&
4435 !Si.lower.hasTag(ERROR) &&
4436 isSameType(tmpBound, tmpLower)) {
4437 currentS.head = Si.getUpperBound();
4438 }
4439 }
4440 currentA = currentA.tail;
4441 currentT = currentT.tail;
4442 currentS = currentS.tail;
4443 }
4444 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
4445 return erasure(t); // some "rare" type involved
4446
4447 if (captured)
4448 return new ClassType(cls.getEnclosingType(), S, cls.tsym,
4449 cls.getMetadata());
4450 else
4451 return t;
4452 }
4453 // where
4454 public List<Type> freshTypeVariables(List<Type> types) {
4455 ListBuffer<Type> result = new ListBuffer<>();
4456 for (Type t : types) {
4457 if (t.hasTag(WILDCARD)) {
4458 Type bound = ((WildcardType)t).getExtendsBound();
4459 if (bound == null)
4460 bound = syms.objectType;
4461 result.append(new CapturedType(capturedName,
4462 syms.noSymbol,
4463 bound,
4464 syms.botType,
4465 (WildcardType)t));
4466 } else {
4467 result.append(t);
4468 }
4469 }
4470 return result.toList();
4471 }
4472 // </editor-fold>
4473
4474 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
4475 private boolean sideCast(Type from, Type to, Warner warn) {
4476 // We are casting from type $from$ to type $to$, which are
4477 // non-final unrelated types. This method
4478 // tries to reject a cast by transferring type parameters
4479 // from $to$ to $from$ by common superinterfaces.
4480 boolean reverse = false;
4481 Type target = to;
4482 if ((to.tsym.flags() & INTERFACE) == 0) {
4483 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4484 reverse = true;
4485 to = from;
4486 from = target;
4487 }
4488 List<Type> commonSupers = superClosure(to, erasure(from));
4489 boolean giveWarning = commonSupers.isEmpty();
4490 // The arguments to the supers could be unified here to
4491 // get a more accurate analysis
4492 while (commonSupers.nonEmpty()) {
4493 Type t1 = asSuper(from, commonSupers.head.tsym);
4494 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
4495 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4496 return false;
4497 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
4498 commonSupers = commonSupers.tail;
4499 }
4500 if (giveWarning && !isReifiable(reverse ? from : to))
4501 warn.warn(LintCategory.UNCHECKED);
4502 return true;
4503 }
4504
4505 private boolean sideCastFinal(Type from, Type to, Warner warn) {
4506 // We are casting from type $from$ to type $to$, which are
4507 // unrelated types one of which is final and the other of
4508 // which is an interface. This method
4509 // tries to reject a cast by transferring type parameters
4510 // from the final class to the interface.
4511 boolean reverse = false;
4512 Type target = to;
4513 if ((to.tsym.flags() & INTERFACE) == 0) {
4514 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4515 reverse = true;
4516 to = from;
4517 from = target;
4518 }
4519 Assert.check((from.tsym.flags() & FINAL) != 0);
4520 Type t1 = asSuper(from, to.tsym);
4521 if (t1 == null) return false;
4522 Type t2 = to;
4523 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4524 return false;
4525 if (!isReifiable(target) &&
4526 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
4527 warn.warn(LintCategory.UNCHECKED);
4528 return true;
4529 }
4530
4531 private boolean giveWarning(Type from, Type to) {
4532 List<Type> bounds = to.isCompound() ?
4533 directSupertypes(to) : List.of(to);
4534 for (Type b : bounds) {
4535 Type subFrom = asSub(from, b.tsym);
4536 if (b.isParameterized() &&
4537 (!(isUnbounded(b) ||
4538 isSubtype(from, b) ||
4539 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
4540 return true;
4541 }
4542 }
4543 return false;
4544 }
4545
4546 private List<Type> superClosure(Type t, Type s) {
4547 List<Type> cl = List.nil();
4548 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
4549 if (isSubtype(s, erasure(l.head))) {
4550 cl = insert(cl, l.head);
4551 } else {
4552 cl = union(cl, superClosure(l.head, s));
4553 }
4554 }
4555 return cl;
4556 }
4557
4558 private boolean containsTypeEquivalent(Type t, Type s) {
4559 return isSameType(t, s) || // shortcut
4560 containsType(t, s) && containsType(s, t);
4561 }
4562
4563 // <editor-fold defaultstate="collapsed" desc="adapt">
4564 /**
4565 * Adapt a type by computing a substitution which maps a source
4566 * type to a target type.
4567 *
4568 * @param source the source type
4569 * @param target the target type
4570 * @param from the type variables of the computed substitution
4571 * @param to the types of the computed substitution.
4572 */
4573 public void adapt(Type source,
4574 Type target,
4575 ListBuffer<Type> from,
4576 ListBuffer<Type> to) throws AdaptFailure {
4577 new Adapter(from, to).adapt(source, target);
4578 }
4579
4580 class Adapter extends SimpleVisitor<Void, Type> {
4581
4582 ListBuffer<Type> from;
4583 ListBuffer<Type> to;
4584 Map<Symbol,Type> mapping;
4585
4586 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
4587 this.from = from;
4588 this.to = to;
4589 mapping = new HashMap<>();
4590 }
4591
4592 public void adapt(Type source, Type target) throws AdaptFailure {
4593 visit(source, target);
4594 List<Type> fromList = from.toList();
4595 List<Type> toList = to.toList();
4596 while (!fromList.isEmpty()) {
4597 Type val = mapping.get(fromList.head.tsym);
4598 if (toList.head != val)
4599 toList.head = val;
4600 fromList = fromList.tail;
4601 toList = toList.tail;
4602 }
4603 }
4604
4605 @Override
4606 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
4607 if (target.hasTag(CLASS))
4608 adaptRecursive(source.allparams(), target.allparams());
4609 return null;
4610 }
4611
4612 @Override
4613 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
4614 if (target.hasTag(ARRAY))
4615 adaptRecursive(elemtype(source), elemtype(target));
4616 return null;
4617 }
4618
4619 @Override
4620 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
4621 if (source.isExtendsBound())
4622 adaptRecursive(wildUpperBound(source), wildUpperBound(target));
4623 else if (source.isSuperBound())
4624 adaptRecursive(wildLowerBound(source), wildLowerBound(target));
4625 return null;
4626 }
4627
4628 @Override
4629 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
4630 // Check to see if there is
4631 // already a mapping for $source$, in which case
4632 // the old mapping will be merged with the new
4633 Type val = mapping.get(source.tsym);
4634 if (val != null) {
4635 if (val.isSuperBound() && target.isSuperBound()) {
4636 val = isSubtype(wildLowerBound(val), wildLowerBound(target))
4637 ? target : val;
4638 } else if (val.isExtendsBound() && target.isExtendsBound()) {
4639 val = isSubtype(wildUpperBound(val), wildUpperBound(target))
4640 ? val : target;
4641 } else if (!isSameType(val, target)) {
4642 throw new AdaptFailure();
4643 }
4644 } else {
4645 val = target;
4646 from.append(source);
4647 to.append(target);
4648 }
4649 mapping.put(source.tsym, val);
4650 return null;
4651 }
4652
4653 @Override
4654 public Void visitType(Type source, Type target) {
4655 return null;
4656 }
4657
4658 private Set<TypePair> cache = new HashSet<>();
4659
4660 private void adaptRecursive(Type source, Type target) {
4661 TypePair pair = new TypePair(source, target);
4662 if (cache.add(pair)) {
4663 try {
4664 visit(source, target);
4665 } finally {
4666 cache.remove(pair);
4667 }
4668 }
4669 }
4670
4671 private void adaptRecursive(List<Type> source, List<Type> target) {
4672 if (source.length() == target.length()) {
4673 while (source.nonEmpty()) {
4674 adaptRecursive(source.head, target.head);
4675 source = source.tail;
4676 target = target.tail;
4677 }
4678 }
4679 }
4680 }
4681
4682 public static class AdaptFailure extends RuntimeException {
4683 static final long serialVersionUID = -7490231548272701566L;
4684 }
4685
4686 private void adaptSelf(Type t,
4687 ListBuffer<Type> from,
4688 ListBuffer<Type> to) {
4689 try {
4690 //if (t.tsym.type != t)
4691 adapt(t.tsym.type, t, from, to);
4692 } catch (AdaptFailure ex) {
4693 // Adapt should never fail calculating a mapping from
4694 // t.tsym.type to t as there can be no merge problem.
4695 throw new AssertionError(ex);
4696 }
4697 }
4698 // </editor-fold>
4699
4700 /**
4701 * Rewrite all type variables (universal quantifiers) in the given
4702 * type to wildcards (existential quantifiers). This is used to
4703 * determine if a cast is allowed. For example, if high is true
4704 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4705 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4706 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4707 * List<Integer>} with a warning.
4708 * @param t a type
4709 * @param high if true return an upper bound; otherwise a lower
4710 * bound
4711 * @param rewriteTypeVars only rewrite captured wildcards if false;
4712 * otherwise rewrite all type variables
4713 * @return the type rewritten with wildcards (existential
4714 * quantifiers) only
4715 */
4716 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4717 return new Rewriter(high, rewriteTypeVars).visit(t);
4718 }
4719
4720 class Rewriter extends UnaryVisitor<Type> {
4721
4722 boolean high;
4723 boolean rewriteTypeVars;
4724
4725 Rewriter(boolean high, boolean rewriteTypeVars) {
4726 this.high = high;
4727 this.rewriteTypeVars = rewriteTypeVars;
4728 }
4729
4730 @Override
4731 public Type visitClassType(ClassType t, Void s) {
4732 ListBuffer<Type> rewritten = new ListBuffer<>();
4733 boolean changed = false;
4734 for (Type arg : t.allparams()) {
4735 Type bound = visit(arg);
4736 if (arg != bound) {
4737 changed = true;
4738 }
4739 rewritten.append(bound);
4740 }
4741 if (changed)
4742 return subst(t.tsym.type,
4743 t.tsym.type.allparams(),
4744 rewritten.toList());
4745 else
4746 return t;
4747 }
4748
4749 public Type visitType(Type t, Void s) {
4750 return t;
4751 }
4752
4753 @Override
4754 public Type visitCapturedType(CapturedType t, Void s) {
4755 Type w_bound = t.wildcard.type;
4756 Type bound = w_bound.contains(t) ?
4757 erasure(w_bound) :
4758 visit(w_bound);
4759 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4760 }
4761
4762 @Override
4763 public Type visitTypeVar(TypeVar t, Void s) {
4764 if (rewriteTypeVars) {
4765 Type bound = t.getUpperBound().contains(t) ?
4766 erasure(t.getUpperBound()) :
4767 visit(t.getUpperBound());
4768 return rewriteAsWildcardType(bound, t, EXTENDS);
4769 } else {
4770 return t;
4771 }
4772 }
4773
4774 @Override
4775 public Type visitWildcardType(WildcardType t, Void s) {
4776 Type bound2 = visit(t.type);
4777 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4778 }
4779
4780 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4781 switch (bk) {
4782 case EXTENDS: return high ?
4783 makeExtendsWildcard(B(bound), formal) :
4784 makeExtendsWildcard(syms.objectType, formal);
4785 case SUPER: return high ?
4786 makeSuperWildcard(syms.botType, formal) :
4787 makeSuperWildcard(B(bound), formal);
4788 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4789 default:
4790 Assert.error("Invalid bound kind " + bk);
4791 return null;
4792 }
4793 }
4794
4795 Type B(Type t) {
4796 while (t.hasTag(WILDCARD)) {
4797 WildcardType w = (WildcardType)t;
4798 t = high ?
4799 w.getExtendsBound() :
4800 w.getSuperBound();
4801 if (t == null) {
4802 t = high ? syms.objectType : syms.botType;
4803 }
4804 }
4805 return t;
4806 }
4807 }
4808
4809
4810 /**
4811 * Create a wildcard with the given upper (extends) bound; create
4812 * an unbounded wildcard if bound is Object.
4813 *
4814 * @param bound the upper bound
4815 * @param formal the formal type parameter that will be
4816 * substituted by the wildcard
4817 */
4818 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4819 if (bound == syms.objectType) {
4820 return new WildcardType(syms.objectType,
4821 BoundKind.UNBOUND,
4822 syms.boundClass,
4823 formal);
4824 } else {
4825 return new WildcardType(bound,
4826 BoundKind.EXTENDS,
4827 syms.boundClass,
4828 formal);
4829 }
4830 }
4831
4832 /**
4833 * Create a wildcard with the given lower (super) bound; create an
4834 * unbounded wildcard if bound is bottom (type of {@code null}).
4835 *
4836 * @param bound the lower bound
4837 * @param formal the formal type parameter that will be
4838 * substituted by the wildcard
4839 */
4840 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4841 if (bound.hasTag(BOT)) {
4842 return new WildcardType(syms.objectType,
4843 BoundKind.UNBOUND,
4844 syms.boundClass,
4845 formal);
4846 } else {
4847 return new WildcardType(bound,
4848 BoundKind.SUPER,
4849 syms.boundClass,
4850 formal);
4851 }
4852 }
4853
4854 /**
4855 * A wrapper for a type that allows use in sets.
4856 */
4857 public static class UniqueType {
4858 public final Type type;
4859 final Types types;
4860
4861 public UniqueType(Type type, Types types) {
4862 this.type = type;
4863 this.types = types;
4864 }
4865
4866 public int hashCode() {
4867 return types.hashCode(type);
4868 }
4869
4870 public boolean equals(Object obj) {
4871 return (obj instanceof UniqueType uniqueType) &&
4872 types.isSameType(type, uniqueType.type);
4873 }
4874
4875 public String toString() {
4876 return type.toString();
4877 }
4878
4879 }
4880 // </editor-fold>
4881
4882 // <editor-fold defaultstate="collapsed" desc="Visitors">
4883 /**
4884 * A default visitor for types. All visitor methods except
4885 * visitType are implemented by delegating to visitType. Concrete
4886 * subclasses must provide an implementation of visitType and can
4887 * override other methods as needed.
4888 *
4889 * @param <R> the return type of the operation implemented by this
4890 * visitor; use Void if no return type is needed.
4891 * @param <S> the type of the second argument (the first being the
4892 * type itself) of the operation implemented by this visitor; use
4893 * Void if a second argument is not needed.
4894 */
4895 public abstract static class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4896 public final R visit(Type t, S s) { return t.accept(this, s); }
4897 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4898 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4899 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4900 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4901 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4902 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); }
4903 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4904 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4905 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4906 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4907 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4908 }
4909
4910 /**
4911 * A default visitor for symbols. All visitor methods except
4912 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4913 * subclasses must provide an implementation of visitSymbol and can
4914 * override other methods as needed.
4915 *
4916 * @param <R> the return type of the operation implemented by this
4917 * visitor; use Void if no return type is needed.
4918 * @param <S> the type of the second argument (the first being the
4919 * symbol itself) of the operation implemented by this visitor; use
4920 * Void if a second argument is not needed.
4921 */
4922 public abstract static class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4923 public final R visit(Symbol s, S arg) { return s.accept(this, arg); }
4924 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4925 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4926 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4927 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4928 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4929 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4930 }
4931
4932 /**
4933 * A <em>simple</em> visitor for types. This visitor is simple as
4934 * captured wildcards, for-all types (generic methods), and
4935 * undetermined type variables (part of inference) are hidden.
4936 * Captured wildcards are hidden by treating them as type
4937 * variables and the rest are hidden by visiting their qtypes.
4938 *
4939 * @param <R> the return type of the operation implemented by this
4940 * visitor; use Void if no return type is needed.
4941 * @param <S> the type of the second argument (the first being the
4942 * type itself) of the operation implemented by this visitor; use
4943 * Void if a second argument is not needed.
4944 */
4945 public abstract static class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4946 @Override
4947 public R visitCapturedType(CapturedType t, S s) {
4948 return visitTypeVar(t, s);
4949 }
4950 @Override
4951 public R visitForAll(ForAll t, S s) {
4952 return visit(t.qtype, s);
4953 }
4954 @Override
4955 public R visitUndetVar(UndetVar t, S s) {
4956 return visit(t.qtype, s);
4957 }
4958 }
4959
4960 /**
4961 * A plain relation on types. That is a 2-ary function on the
4962 * form Type × Type → Boolean.
4963 * <!-- In plain text: Type x Type -> Boolean -->
4964 */
4965 public abstract static class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4966
4967 /**
4968 * A convenience visitor for implementing operations that only
4969 * require one argument (the type itself), that is, unary
4970 * operations.
4971 *
4972 * @param <R> the return type of the operation implemented by this
4973 * visitor; use Void if no return type is needed.
4974 */
4975 public abstract static class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4976 public final R visit(Type t) { return t.accept(this, null); }
4977 }
4978
4979 /**
4980 * A visitor for implementing a mapping from types to types. The
4981 * default behavior of this class is to implement the identity
4982 * mapping (mapping a type to itself). This can be overridden in
4983 * subclasses.
4984 *
4985 * @param <S> the type of the second argument (the first being the
4986 * type itself) of this mapping; use Void if a second argument is
4987 * not needed.
4988 */
4989 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4990 public final Type visit(Type t) { return t.accept(this, null); }
4991 public Type visitType(Type t, S s) { return t; }
4992 }
4993
4994 /**
4995 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}.
4996 * This class implements the functional interface {@code Function}, that allows it to be used
4997 * fluently in stream-like processing.
4998 */
4999 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> {
5000 @Override
5001 public Type apply(Type type) { return visit(type); }
5002
5003 List<Type> visit(List<Type> ts, S s) {
5004 return ts.map(t -> visit(t, s));
5005 }
5006
5007 @Override
5008 public Type visitCapturedType(CapturedType t, S s) {
5009 return visitTypeVar(t, s);
5010 }
5011 }
5012 // </editor-fold>
5013
5014
5015 // <editor-fold defaultstate="collapsed" desc="Annotation support">
5016
5017 public RetentionPolicy getRetention(Attribute.Compound a) {
5018 return getRetention(a.type.tsym);
5019 }
5020
5021 public RetentionPolicy getRetention(TypeSymbol sym) {
5022 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
5023 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
5024 if (c != null) {
5025 Attribute value = c.member(names.value);
5026 if (value != null && value instanceof Attribute.Enum attributeEnum) {
5027 Name levelName = attributeEnum.value.name;
5028 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
5029 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
5030 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
5031 else ;// /* fail soft */ throw new AssertionError(levelName);
5032 }
5033 }
5034 return vis;
5035 }
5036 // </editor-fold>
5037
5038 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
5039
5040 public abstract static class SignatureGenerator {
5041
5042 public static class InvalidSignatureException extends RuntimeException {
5043 private static final long serialVersionUID = 0;
5044
5045 private final transient Type type;
5046
5047 InvalidSignatureException(Type type) {
5048 this.type = type;
5049 }
5050
5051 public Type type() {
5052 return type;
5053 }
5054
5055 @Override
5056 public Throwable fillInStackTrace() {
5057 // This is an internal exception; the stack trace is irrelevant.
5058 return this;
5059 }
5060 }
5061
5062 private final Types types;
5063
5064 protected abstract void append(char ch);
5065 protected abstract void append(byte[] ba);
5066 protected abstract void append(Name name);
5067 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
5068
5069 protected SignatureGenerator(Types types) {
5070 this.types = types;
5071 }
5072
5073 protected void reportIllegalSignature(Type t) {
5074 throw new InvalidSignatureException(t);
5075 }
5076
5077 /**
5078 * Assemble signature of given type in string buffer.
5079 */
5080 public void assembleSig(Type type) {
5081 switch (type.getTag()) {
5082 case BYTE:
5083 append('B');
5084 break;
5085 case SHORT:
5086 append('S');
5087 break;
5088 case CHAR:
5089 append('C');
5090 break;
5091 case INT:
5092 append('I');
5093 break;
5094 case LONG:
5095 append('J');
5096 break;
5097 case FLOAT:
5098 append('F');
5099 break;
5100 case DOUBLE:
5101 append('D');
5102 break;
5103 case BOOLEAN:
5104 append('Z');
5105 break;
5106 case VOID:
5107 append('V');
5108 break;
5109 case CLASS:
5110 if (type.isCompound()) {
5111 reportIllegalSignature(type);
5112 }
5113 append('L');
5114 assembleClassSig(type);
5115 append(';');
5116 break;
5117 case ARRAY:
5118 ArrayType at = (ArrayType) type;
5119 append('[');
5120 assembleSig(at.elemtype);
5121 break;
5122 case METHOD:
5123 MethodType mt = (MethodType) type;
5124 append('(');
5125 assembleSig(mt.argtypes);
5126 append(')');
5127 assembleSig(mt.restype);
5128 if (hasTypeVar(mt.thrown)) {
5129 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
5130 append('^');
5131 assembleSig(l.head);
5132 }
5133 }
5134 break;
5135 case WILDCARD: {
5136 Type.WildcardType ta = (Type.WildcardType) type;
5137 switch (ta.kind) {
5138 case SUPER:
5139 append('-');
5140 assembleSig(ta.type);
5141 break;
5142 case EXTENDS:
5143 append('+');
5144 assembleSig(ta.type);
5145 break;
5146 case UNBOUND:
5147 append('*');
5148 break;
5149 default:
5150 throw new AssertionError(ta.kind);
5151 }
5152 break;
5153 }
5154 case TYPEVAR:
5155 if (((TypeVar)type).isCaptured()) {
5156 reportIllegalSignature(type);
5157 }
5158 append('T');
5159 append(type.tsym.name);
5160 append(';');
5161 break;
5162 case FORALL:
5163 Type.ForAll ft = (Type.ForAll) type;
5164 assembleParamsSig(ft.tvars);
5165 assembleSig(ft.qtype);
5166 break;
5167 default:
5168 throw new AssertionError("typeSig " + type.getTag());
5169 }
5170 }
5171
5172 public boolean hasTypeVar(List<Type> l) {
5173 while (l.nonEmpty()) {
5174 if (l.head.hasTag(TypeTag.TYPEVAR)) {
5175 return true;
5176 }
5177 l = l.tail;
5178 }
5179 return false;
5180 }
5181
5182 public void assembleClassSig(Type type) {
5183 ClassType ct = (ClassType) type;
5184 ClassSymbol c = (ClassSymbol) ct.tsym;
5185 classReference(c);
5186 Type outer = ct.getEnclosingType();
5187 if (outer.allparams().nonEmpty()) {
5188 boolean rawOuter =
5189 c.owner.kind == MTH || // either a local class
5190 c.name == types.names.empty; // or anonymous
5191 assembleClassSig(rawOuter
5192 ? types.erasure(outer)
5193 : outer);
5194 append(rawOuter ? '$' : '.');
5195 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
5196 append(rawOuter
5197 ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength())
5198 : c.name);
5199 } else {
5200 append(externalize(c.flatname));
5201 }
5202 if (ct.getTypeArguments().nonEmpty()) {
5203 append('<');
5204 assembleSig(ct.getTypeArguments());
5205 append('>');
5206 }
5207 }
5208
5209 public void assembleParamsSig(List<Type> typarams) {
5210 append('<');
5211 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
5212 Type.TypeVar tvar = (Type.TypeVar) ts.head;
5213 append(tvar.tsym.name);
5214 List<Type> bounds = types.getBounds(tvar);
5215 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
5216 append(':');
5217 }
5218 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
5219 append(':');
5220 assembleSig(l.head);
5221 }
5222 }
5223 append('>');
5224 }
5225
5226 public void assembleSig(List<Type> types) {
5227 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
5228 assembleSig(ts.head);
5229 }
5230 }
5231 }
5232
5233 public Type constantType(LoadableConstant c) {
5234 switch (c.poolTag()) {
5235 case ClassFile.CONSTANT_Class:
5236 return syms.classType;
5237 case ClassFile.CONSTANT_String:
5238 return syms.stringType;
5239 case ClassFile.CONSTANT_Integer:
5240 return syms.intType;
5241 case ClassFile.CONSTANT_Float:
5242 return syms.floatType;
5243 case ClassFile.CONSTANT_Long:
5244 return syms.longType;
5245 case ClassFile.CONSTANT_Double:
5246 return syms.doubleType;
5247 case ClassFile.CONSTANT_MethodHandle:
5248 return syms.methodHandleType;
5249 case ClassFile.CONSTANT_MethodType:
5250 return syms.methodTypeType;
5251 case ClassFile.CONSTANT_Dynamic:
5252 return ((DynamicVarSymbol)c).type;
5253 default:
5254 throw new AssertionError("Not a loadable constant: " + c.poolTag());
5255 }
5256 }
5257 // </editor-fold>
5258
5259 public void newRound() {
5260 descCache._map.clear();
5261 isDerivedRawCache.clear();
5262 implCache._map.clear();
5263 membersCache._map.clear();
5264 closureCache.clear();
5265 }
5266 }