1 /*
2 * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.tools.javac.code;
27
28 import java.lang.ref.SoftReference;
29 import java.util.HashSet;
30 import java.util.HashMap;
31 import java.util.Locale;
32 import java.util.Map;
33 import java.util.Optional;
34 import java.util.Set;
35 import java.util.WeakHashMap;
36 import java.util.function.BiFunction;
37 import java.util.function.BiPredicate;
38 import java.util.function.Function;
39 import java.util.function.Predicate;
40 import java.util.stream.Collector;
41
42 import javax.tools.JavaFileObject;
43
44 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
45 import com.sun.tools.javac.code.Lint.LintCategory;
46 import com.sun.tools.javac.code.Source.Feature;
47 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
48 import com.sun.tools.javac.code.TypeMetadata.Annotations;
49 import com.sun.tools.javac.comp.AttrContext;
50 import com.sun.tools.javac.comp.Check;
51 import com.sun.tools.javac.comp.Enter;
52 import com.sun.tools.javac.comp.Env;
53 import com.sun.tools.javac.jvm.ClassFile;
54 import com.sun.tools.javac.util.*;
55
56 import static com.sun.tools.javac.code.BoundKind.*;
57 import static com.sun.tools.javac.code.Flags.*;
58 import static com.sun.tools.javac.code.Kinds.Kind.*;
59 import static com.sun.tools.javac.code.Scope.*;
60 import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
61 import static com.sun.tools.javac.code.Symbol.*;
62 import static com.sun.tools.javac.code.Type.*;
63 import static com.sun.tools.javac.code.TypeTag.*;
64 import static com.sun.tools.javac.jvm.ClassFile.externalize;
65 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
66
67 /**
68 * Utility class containing various operations on types.
69 *
70 * <p>Unless other names are more illustrative, the following naming
71 * conventions should be observed in this file:
72 *
73 * <dl>
74 * <dt>t</dt>
75 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
76 * <dt>s</dt>
77 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
78 * <dt>ts</dt>
79 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
80 * <dt>ss</dt>
81 * <dd>A second list of types should be named ss.</dd>
82 * </dl>
83 *
84 * <p><b>This is NOT part of any supported API.
85 * If you write code that depends on this, you do so at your own risk.
86 * This code and its internal interfaces are subject to change or
87 * deletion without notice.</b>
88 */
89 public class Types {
90 protected static final Context.Key<Types> typesKey = new Context.Key<>();
91
92 final Symtab syms;
93 final JavacMessages messages;
94 final Names names;
95 final Check chk;
96 final Enter enter;
97 JCDiagnostic.Factory diags;
98 List<Warner> warnStack = List.nil();
99 final Name capturedName;
100
101 public final Warner noWarnings;
102
103 // <editor-fold defaultstate="collapsed" desc="Instantiating">
104 public static Types instance(Context context) {
105 Types instance = context.get(typesKey);
106 if (instance == null)
107 instance = new Types(context);
108 return instance;
109 }
110
111 @SuppressWarnings("this-escape")
112 protected Types(Context context) {
113 context.put(typesKey, this);
114 syms = Symtab.instance(context);
115 names = Names.instance(context);
116 Source source = Source.instance(context);
117 chk = Check.instance(context);
118 enter = Enter.instance(context);
119 capturedName = names.fromString("<captured wildcard>");
120 messages = JavacMessages.instance(context);
121 diags = JCDiagnostic.Factory.instance(context);
122 noWarnings = new Warner(null) {
123 @Override
124 public String toString() {
125 return "NO_WARNINGS";
126 }
127 };
128 }
129 // </editor-fold>
130
131 // <editor-fold defaultstate="collapsed" desc="bounds">
132 /**
133 * Get a wildcard's upper bound, returning non-wildcards unchanged.
134 * @param t a type argument, either a wildcard or a type
135 */
136 public Type wildUpperBound(Type t) {
137 if (t.hasTag(WILDCARD)) {
138 WildcardType w = (WildcardType) t;
139 if (w.isSuperBound())
140 return w.bound == null ? syms.objectType : w.bound.getUpperBound();
141 else
142 return wildUpperBound(w.type);
143 }
144 else return t;
145 }
146
147 /**
148 * Get a capture variable's upper bound, returning other types unchanged.
149 * @param t a type
150 */
151 public Type cvarUpperBound(Type t) {
152 if (t.hasTag(TYPEVAR)) {
153 TypeVar v = (TypeVar) t;
154 return v.isCaptured() ? cvarUpperBound(v.getUpperBound()) : v;
155 }
156 else return t;
157 }
158
159 /**
160 * Get a wildcard's lower bound, returning non-wildcards unchanged.
161 * @param t a type argument, either a wildcard or a type
162 */
163 public Type wildLowerBound(Type t) {
164 if (t.hasTag(WILDCARD)) {
165 WildcardType w = (WildcardType) t;
166 return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type);
167 }
168 else return t;
169 }
170
171 /**
172 * Get a capture variable's lower bound, returning other types unchanged.
173 * @param t a type
174 */
175 public Type cvarLowerBound(Type t) {
176 if (t.hasTag(TYPEVAR) && ((TypeVar) t).isCaptured()) {
177 return cvarLowerBound(t.getLowerBound());
178 }
179 else return t;
180 }
181
182 /**
183 * Recursively skip type-variables until a class/array type is found; capture conversion is then
184 * (optionally) applied to the resulting type. This is useful for i.e. computing a site that is
185 * suitable for a method lookup.
186 */
187 public Type skipTypeVars(Type site, boolean capture) {
188 while (site.hasTag(TYPEVAR)) {
189 site = site.getUpperBound();
190 }
191 return capture ? capture(site) : site;
192 }
193 // </editor-fold>
194
195 // <editor-fold defaultstate="collapsed" desc="projections">
196
197 /**
198 * A projection kind. See {@link TypeProjection}
199 */
200 enum ProjectionKind {
201 UPWARDS() {
202 @Override
203 ProjectionKind complement() {
204 return DOWNWARDS;
205 }
206 },
207 DOWNWARDS() {
208 @Override
209 ProjectionKind complement() {
210 return UPWARDS;
211 }
212 };
213
214 abstract ProjectionKind complement();
215 }
216
217 /**
218 * This visitor performs upwards and downwards projections on types.
219 *
220 * A projection is defined as a function that takes a type T, a set of type variables V and that
221 * produces another type S.
222 *
223 * An upwards projection maps a type T into a type S such that (i) T has no variables in V,
224 * and (ii) S is an upper bound of T.
225 *
226 * A downwards projection maps a type T into a type S such that (i) T has no variables in V,
227 * and (ii) S is a lower bound of T.
228 *
229 * Note that projections are only allowed to touch variables in V. Therefore, it is possible for
230 * a projection to leave its input type unchanged if it does not contain any variables in V.
231 *
232 * Moreover, note that while an upwards projection is always defined (every type as an upper bound),
233 * a downwards projection is not always defined.
234 *
235 * Examples:
236 *
237 * {@code upwards(List<#CAP1>, [#CAP1]) = List<? extends String>, where #CAP1 <: String }
238 * {@code downwards(List<#CAP2>, [#CAP2]) = List<? super String>, where #CAP2 :> String }
239 * {@code upwards(List<#CAP1>, [#CAP2]) = List<#CAP1> }
240 * {@code downwards(List<#CAP1>, [#CAP1]) = not defined }
241 */
242 class TypeProjection extends TypeMapping<ProjectionKind> {
243
244 List<Type> vars;
245 Set<Type> seen = new HashSet<>();
246
247 public TypeProjection(List<Type> vars) {
248 this.vars = vars;
249 }
250
251 @Override
252 public Type visitClassType(ClassType t, ProjectionKind pkind) {
253 if (t.isCompound()) {
254 List<Type> components = directSupertypes(t);
255 List<Type> components1 = components.map(c -> c.map(this, pkind));
256 if (components == components1) return t;
257 else return makeIntersectionType(components1);
258 } else {
259 Type outer = t.getEnclosingType();
260 Type outer1 = visit(outer, pkind);
261 List<Type> typarams = t.getTypeArguments();
262 List<Type> formals = t.tsym.type.getTypeArguments();
263 ListBuffer<Type> typarams1 = new ListBuffer<>();
264 boolean changed = false;
265 for (Type actual : typarams) {
266 Type t2 = mapTypeArgument(t, formals.head.getUpperBound(), actual, pkind);
267 if (t2.hasTag(BOT)) {
268 //not defined
269 return syms.botType;
270 }
271 typarams1.add(t2);
272 changed |= actual != t2;
273 formals = formals.tail;
274 }
275 if (outer1 == outer && !changed) return t;
276 else return new ClassType(outer1, typarams1.toList(), t.tsym, t.getMetadata()) {
277 @Override
278 protected boolean needsStripping() {
279 return true;
280 }
281 };
282 }
283 }
284
285 @Override
286 public Type visitArrayType(ArrayType t, ProjectionKind s) {
287 Type elemtype = t.elemtype;
288 Type elemtype1 = visit(elemtype, s);
289 if (elemtype1 == elemtype) {
290 return t;
291 } else if (elemtype1.hasTag(BOT)) {
292 //undefined
293 return syms.botType;
294 } else {
295 return new ArrayType(elemtype1, t.tsym, t.metadata) {
296 @Override
297 protected boolean needsStripping() {
298 return true;
299 }
300 };
301 }
302 }
303
304 @Override
305 public Type visitTypeVar(TypeVar t, ProjectionKind pkind) {
306 if (vars.contains(t)) {
307 if (seen.add(t)) {
308 try {
309 final Type bound;
310 switch (pkind) {
311 case UPWARDS:
312 bound = t.getUpperBound();
313 break;
314 case DOWNWARDS:
315 bound = (t.getLowerBound() == null) ?
316 syms.botType :
317 t.getLowerBound();
318 break;
319 default:
320 Assert.error();
321 return null;
322 }
323 return bound.map(this, pkind);
324 } finally {
325 seen.remove(t);
326 }
327 } else {
328 //cycle
329 return pkind == ProjectionKind.UPWARDS ?
330 syms.objectType : syms.botType;
331 }
332 } else {
333 return t;
334 }
335 }
336
337 private Type mapTypeArgument(Type site, Type declaredBound, Type t, ProjectionKind pkind) {
338 return t.containsAny(vars) ?
339 t.map(new TypeArgumentProjection(site, declaredBound), pkind) :
340 t;
341 }
342
343 class TypeArgumentProjection extends TypeMapping<ProjectionKind> {
344
345 Type site;
346 Type declaredBound;
347
348 TypeArgumentProjection(Type site, Type declaredBound) {
349 this.site = site;
350 this.declaredBound = declaredBound;
351 }
352
353 @Override
354 public Type visitType(Type t, ProjectionKind pkind) {
355 //type argument is some type containing restricted vars
356 if (pkind == ProjectionKind.DOWNWARDS) {
357 //not defined
358 return syms.botType;
359 }
360 Type upper = t.map(TypeProjection.this, ProjectionKind.UPWARDS);
361 Type lower = t.map(TypeProjection.this, ProjectionKind.DOWNWARDS);
362 List<Type> formals = site.tsym.type.getTypeArguments();
363 BoundKind bk;
364 Type bound;
365 if (!isSameType(upper, syms.objectType) &&
366 (declaredBound.containsAny(formals) ||
367 !isSubtype(declaredBound, upper))) {
368 bound = upper;
369 bk = EXTENDS;
370 } else if (!lower.hasTag(BOT)) {
371 bound = lower;
372 bk = SUPER;
373 } else {
374 bound = syms.objectType;
375 bk = UNBOUND;
376 }
377 return makeWildcard(bound, bk);
378 }
379
380 @Override
381 public Type visitWildcardType(WildcardType wt, ProjectionKind pkind) {
382 //type argument is some wildcard whose bound contains restricted vars
383 Type bound = syms.botType;
384 BoundKind bk = wt.kind;
385 switch (wt.kind) {
386 case EXTENDS:
387 bound = wt.type.map(TypeProjection.this, pkind);
388 if (bound.hasTag(BOT)) {
389 return syms.botType;
390 }
391 break;
392 case SUPER:
393 bound = wt.type.map(TypeProjection.this, pkind.complement());
394 if (bound.hasTag(BOT)) {
395 bound = syms.objectType;
396 bk = UNBOUND;
397 }
398 break;
399 }
400 return makeWildcard(bound, bk);
401 }
402
403 private Type makeWildcard(Type bound, BoundKind bk) {
404 return new WildcardType(bound, bk, syms.boundClass) {
405 @Override
406 protected boolean needsStripping() {
407 return true;
408 }
409 };
410 }
411 }
412 }
413
414 /**
415 * Computes an upward projection of given type, and vars. See {@link TypeProjection}.
416 *
417 * @param t the type to be projected
418 * @param vars the set of type variables to be mapped
419 * @return the type obtained as result of the projection
420 */
421 public Type upward(Type t, List<Type> vars) {
422 return t.map(new TypeProjection(vars), ProjectionKind.UPWARDS);
423 }
424
425 /**
426 * Computes the set of captured variables mentioned in a given type. See {@link CaptureScanner}.
427 * This routine is typically used to computed the input set of variables to be used during
428 * an upwards projection (see {@link Types#upward(Type, List)}).
429 *
430 * @param t the type where occurrences of captured variables have to be found
431 * @return the set of captured variables found in t
432 */
433 public List<Type> captures(Type t) {
434 CaptureScanner cs = new CaptureScanner();
435 Set<Type> captures = new HashSet<>();
436 cs.visit(t, captures);
437 return List.from(captures);
438 }
439
440 /**
441 * This visitor scans a type recursively looking for occurrences of captured type variables.
442 */
443 class CaptureScanner extends SimpleVisitor<Void, Set<Type>> {
444
445 @Override
446 public Void visitType(Type t, Set<Type> types) {
447 return null;
448 }
449
450 @Override
451 public Void visitClassType(ClassType t, Set<Type> seen) {
452 if (t.isCompound()) {
453 directSupertypes(t).forEach(s -> visit(s, seen));
454 } else {
455 t.allparams().forEach(ta -> visit(ta, seen));
456 }
457 return null;
458 }
459
460 @Override
461 public Void visitArrayType(ArrayType t, Set<Type> seen) {
462 return visit(t.elemtype, seen);
463 }
464
465 @Override
466 public Void visitWildcardType(WildcardType t, Set<Type> seen) {
467 visit(t.type, seen);
468 return null;
469 }
470
471 @Override
472 public Void visitTypeVar(TypeVar t, Set<Type> seen) {
473 if ((t.tsym.flags() & Flags.SYNTHETIC) != 0 && seen.add(t)) {
474 visit(t.getUpperBound(), seen);
475 }
476 return null;
477 }
478
479 @Override
480 public Void visitCapturedType(CapturedType t, Set<Type> seen) {
481 if (seen.add(t)) {
482 visit(t.getUpperBound(), seen);
483 visit(t.getLowerBound(), seen);
484 }
485 return null;
486 }
487 }
488
489 // </editor-fold>
490
491 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
492 /**
493 * Checks that all the arguments to a class are unbounded
494 * wildcards or something else that doesn't make any restrictions
495 * on the arguments. If a class isUnbounded, a raw super- or
496 * subclass can be cast to it without a warning.
497 * @param t a type
498 * @return true iff the given type is unbounded or raw
499 */
500 public boolean isUnbounded(Type t) {
501 return isUnbounded.visit(t);
502 }
503 // where
504 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
505
506 public Boolean visitType(Type t, Void ignored) {
507 return true;
508 }
509
510 @Override
511 public Boolean visitClassType(ClassType t, Void ignored) {
512 List<Type> parms = t.tsym.type.allparams();
513 List<Type> args = t.allparams();
514 while (parms.nonEmpty()) {
515 WildcardType unb = new WildcardType(syms.objectType,
516 BoundKind.UNBOUND,
517 syms.boundClass,
518 (TypeVar)parms.head);
519 if (!containsType(args.head, unb))
520 return false;
521 parms = parms.tail;
522 args = args.tail;
523 }
524 return true;
525 }
526 };
527 // </editor-fold>
528
529 // <editor-fold defaultstate="collapsed" desc="asSub">
530 /**
531 * Return the least specific subtype of t that starts with symbol
532 * sym. If none exists, return null. The least specific subtype
533 * is determined as follows:
534 *
535 * <p>If there is exactly one parameterized instance of sym that is a
536 * subtype of t, that parameterized instance is returned.<br>
537 * Otherwise, if the plain type or raw type `sym' is a subtype of
538 * type t, the type `sym' itself is returned. Otherwise, null is
539 * returned.
540 */
541 public Type asSub(Type t, Symbol sym) {
542 return asSub.visit(t, sym);
543 }
544 // where
545 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
546
547 public Type visitType(Type t, Symbol sym) {
548 return null;
549 }
550
551 @Override
552 public Type visitClassType(ClassType t, Symbol sym) {
553 if (t.tsym == sym)
554 return t;
555 Type base = asSuper(sym.type, t.tsym);
556 if (base == null)
557 return null;
558 ListBuffer<Type> from = new ListBuffer<>();
559 ListBuffer<Type> to = new ListBuffer<>();
560 try {
561 adapt(base, t, from, to);
562 } catch (AdaptFailure ex) {
563 return null;
564 }
565 Type res = subst(sym.type, from.toList(), to.toList());
566 if (!isSubtype(res, t))
567 return null;
568 ListBuffer<Type> openVars = new ListBuffer<>();
569 for (List<Type> l = sym.type.allparams();
570 l.nonEmpty(); l = l.tail)
571 if (res.contains(l.head) && !t.contains(l.head))
572 openVars.append(l.head);
573 if (openVars.nonEmpty()) {
574 if (t.isRaw()) {
575 // The subtype of a raw type is raw
576 res = erasure(res);
577 } else {
578 // Unbound type arguments default to ?
579 List<Type> opens = openVars.toList();
580 ListBuffer<Type> qs = new ListBuffer<>();
581 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
582 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND,
583 syms.boundClass, (TypeVar) iter.head));
584 }
585 res = subst(res, opens, qs.toList());
586 }
587 }
588 return res;
589 }
590
591 @Override
592 public Type visitErrorType(ErrorType t, Symbol sym) {
593 return t;
594 }
595 };
596 // </editor-fold>
597
598 // <editor-fold defaultstate="collapsed" desc="isConvertible">
599 /**
600 * Is t a subtype of or convertible via boxing/unboxing
601 * conversion to s?
602 */
603 public boolean isConvertible(Type t, Type s, Warner warn) {
604 if (t.hasTag(ERROR)) {
605 return true;
606 }
607 boolean tPrimitive = t.isPrimitive();
608 boolean sPrimitive = s.isPrimitive();
609 if (tPrimitive == sPrimitive) {
610 return isSubtypeUnchecked(t, s, warn);
611 }
612 boolean tUndet = t.hasTag(UNDETVAR);
613 boolean sUndet = s.hasTag(UNDETVAR);
614
615 if (tUndet || sUndet) {
616 return tUndet ?
617 isSubtype(t, boxedTypeOrType(s)) :
618 isSubtype(boxedTypeOrType(t), s);
619 }
620
621 return tPrimitive
622 ? isSubtype(boxedClass(t).type, s)
623 : isSubtype(unboxedType(t), s);
624 }
625
626 /**
627 * Is t a subtype of or convertible via boxing/unboxing
628 * conversions to s?
629 */
630 public boolean isConvertible(Type t, Type s) {
631 return isConvertible(t, s, noWarnings);
632 }
633 // </editor-fold>
634
635 // <editor-fold defaultstate="collapsed" desc="findSam">
636
637 /**
638 * Exception used to report a function descriptor lookup failure. The exception
639 * wraps a diagnostic that can be used to generate more details error
640 * messages.
641 */
642 public static class FunctionDescriptorLookupError extends RuntimeException {
643 private static final long serialVersionUID = 0;
644
645 transient JCDiagnostic diagnostic;
646
647 FunctionDescriptorLookupError() {
648 this.diagnostic = null;
649 }
650
651 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
652 this.diagnostic = diag;
653 return this;
654 }
655
656 public JCDiagnostic getDiagnostic() {
657 return diagnostic;
658 }
659
660 @Override
661 public Throwable fillInStackTrace() {
662 // This is an internal exception; the stack trace is irrelevant.
663 return this;
664 }
665 }
666
667 /**
668 * A cache that keeps track of function descriptors associated with given
669 * functional interfaces.
670 */
671 class DescriptorCache {
672
673 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<>();
674
675 class FunctionDescriptor {
676 Symbol descSym;
677
678 FunctionDescriptor(Symbol descSym) {
679 this.descSym = descSym;
680 }
681
682 public Symbol getSymbol() {
683 return descSym;
684 }
685
686 public Type getType(Type site) {
687 site = removeWildcards(site);
688 if (site.isIntersection()) {
689 IntersectionClassType ict = (IntersectionClassType)site;
690 for (Type component : ict.getExplicitComponents()) {
691 if (!chk.checkValidGenericType(component)) {
692 //if the inferred functional interface type is not well-formed,
693 //or if it's not a subtype of the original target, issue an error
694 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
695 }
696 }
697 } else {
698 if (!chk.checkValidGenericType(site)) {
699 //if the inferred functional interface type is not well-formed,
700 //or if it's not a subtype of the original target, issue an error
701 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
702 }
703 }
704 return memberType(site, descSym);
705 }
706 }
707
708 class Entry {
709 final FunctionDescriptor cachedDescRes;
710 final int prevMark;
711
712 public Entry(FunctionDescriptor cachedDescRes,
713 int prevMark) {
714 this.cachedDescRes = cachedDescRes;
715 this.prevMark = prevMark;
716 }
717
718 boolean matches(int mark) {
719 return this.prevMark == mark;
720 }
721 }
722
723 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
724 Entry e = _map.get(origin);
725 CompoundScope members = membersClosure(origin.type, false);
726 if (e == null ||
727 !e.matches(members.getMark())) {
728 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
729 _map.put(origin, new Entry(descRes, members.getMark()));
730 return descRes;
731 }
732 else {
733 return e.cachedDescRes;
734 }
735 }
736
737 /**
738 * Compute the function descriptor associated with a given functional interface
739 */
740 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin,
741 CompoundScope membersCache) throws FunctionDescriptorLookupError {
742 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0 || origin.isSealed()) {
743 //t must be an interface
744 throw failure("not.a.functional.intf", origin);
745 }
746
747 final ListBuffer<Symbol> abstracts = new ListBuffer<>();
748 for (Symbol sym : membersCache.getSymbols(new DescriptorFilter(origin))) {
749 Type mtype = memberType(origin.type, sym);
750 if (abstracts.isEmpty()) {
751 abstracts.append(sym);
752 } else if ((sym.name == abstracts.first().name &&
753 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
754 if (!abstracts.stream().filter(msym -> msym.owner.isSubClass(sym.enclClass(), Types.this))
755 .map(msym -> memberType(origin.type, msym))
756 .anyMatch(abstractMType -> isSubSignature(abstractMType, mtype))) {
757 abstracts.append(sym);
758 }
759 } else {
760 //the target method(s) should be the only abstract members of t
761 throw failure("not.a.functional.intf.1", origin,
762 diags.fragment(Fragments.IncompatibleAbstracts(Kinds.kindName(origin), origin)));
763 }
764 }
765 if (abstracts.isEmpty()) {
766 //t must define a suitable non-generic method
767 throw failure("not.a.functional.intf.1", origin,
768 diags.fragment(Fragments.NoAbstracts(Kinds.kindName(origin), origin)));
769 } else if (abstracts.size() == 1) {
770 return new FunctionDescriptor(abstracts.first());
771 } else { // size > 1
772 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
773 if (descRes == null) {
774 //we can get here if the functional interface is ill-formed
775 ListBuffer<JCDiagnostic> descriptors = new ListBuffer<>();
776 for (Symbol desc : abstracts) {
777 String key = desc.type.getThrownTypes().nonEmpty() ?
778 "descriptor.throws" : "descriptor";
779 descriptors.append(diags.fragment(key, desc.name,
780 desc.type.getParameterTypes(),
781 desc.type.getReturnType(),
782 desc.type.getThrownTypes()));
783 }
784 JCDiagnostic msg =
785 diags.fragment(Fragments.IncompatibleDescsInFunctionalIntf(Kinds.kindName(origin),
786 origin));
787 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
788 new JCDiagnostic.MultilineDiagnostic(msg, descriptors.toList());
789 throw failure(incompatibleDescriptors);
790 }
791 return descRes;
792 }
793 }
794
795 /**
796 * Compute a synthetic type for the target descriptor given a list
797 * of override-equivalent methods in the functional interface type.
798 * The resulting method type is a method type that is override-equivalent
799 * and return-type substitutable with each method in the original list.
800 */
801 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
802 return mergeAbstracts(methodSyms, origin.type, false)
803 .map(bestSoFar -> new FunctionDescriptor(bestSoFar.baseSymbol()) {
804 @Override
805 public Type getType(Type origin) {
806 Type mt = memberType(origin, getSymbol());
807 return createMethodTypeWithThrown(mt, bestSoFar.type.getThrownTypes());
808 }
809 }).orElse(null);
810 }
811
812 FunctionDescriptorLookupError failure(String msg, Object... args) {
813 return failure(diags.fragment(msg, args));
814 }
815
816 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
817 return new FunctionDescriptorLookupError().setMessage(diag);
818 }
819 }
820
821 private DescriptorCache descCache = new DescriptorCache();
822
823 /**
824 * Find the method descriptor associated to this class symbol - if the
825 * symbol 'origin' is not a functional interface, an exception is thrown.
826 */
827 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
828 return descCache.get(origin).getSymbol();
829 }
830
831 /**
832 * Find the type of the method descriptor associated to this class symbol -
833 * if the symbol 'origin' is not a functional interface, an exception is thrown.
834 */
835 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
836 return descCache.get(origin.tsym).getType(origin);
837 }
838
839 /**
840 * Is given type a functional interface?
841 */
842 public boolean isFunctionalInterface(TypeSymbol tsym) {
843 try {
844 findDescriptorSymbol(tsym);
845 return true;
846 } catch (FunctionDescriptorLookupError ex) {
847 return false;
848 }
849 }
850
851 public boolean isFunctionalInterface(Type site) {
852 try {
853 findDescriptorType(site);
854 return true;
855 } catch (FunctionDescriptorLookupError ex) {
856 return false;
857 }
858 }
859
860 public Type removeWildcards(Type site) {
861 if (site.getTypeArguments().stream().anyMatch(t -> t.hasTag(WILDCARD))) {
862 //compute non-wildcard parameterization - JLS 9.9
863 List<Type> actuals = site.getTypeArguments();
864 List<Type> formals = site.tsym.type.getTypeArguments();
865 ListBuffer<Type> targs = new ListBuffer<>();
866 for (Type formal : formals) {
867 Type actual = actuals.head;
868 Type bound = formal.getUpperBound();
869 if (actuals.head.hasTag(WILDCARD)) {
870 WildcardType wt = (WildcardType)actual;
871 //check that bound does not contain other formals
872 if (bound.containsAny(formals)) {
873 targs.add(wt.type);
874 } else {
875 //compute new type-argument based on declared bound and wildcard bound
876 switch (wt.kind) {
877 case UNBOUND:
878 targs.add(bound);
879 break;
880 case EXTENDS:
881 targs.add(glb(bound, wt.type));
882 break;
883 case SUPER:
884 targs.add(wt.type);
885 break;
886 default:
887 Assert.error("Cannot get here!");
888 }
889 }
890 } else {
891 //not a wildcard - the new type argument remains unchanged
892 targs.add(actual);
893 }
894 actuals = actuals.tail;
895 }
896 return subst(site.tsym.type, formals, targs.toList());
897 } else {
898 return site;
899 }
900 }
901
902 /**
903 * Create a symbol for a class that implements a given functional interface
904 * and overrides its functional descriptor. This routine is used for two
905 * main purposes: (i) checking well-formedness of a functional interface;
906 * (ii) perform functional interface bridge calculation.
907 */
908 public ClassSymbol makeFunctionalInterfaceClass(Env<AttrContext> env, Name name, Type target, long cflags) {
909 if (target == null || target == syms.unknownType) {
910 return null;
911 }
912 Symbol descSym = findDescriptorSymbol(target.tsym);
913 Type descType = findDescriptorType(target);
914 ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass());
915 csym.completer = Completer.NULL_COMPLETER;
916 csym.members_field = WriteableScope.create(csym);
917 MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym);
918 csym.members_field.enter(instDescSym);
919 Type.ClassType ctype = new Type.ClassType(Type.noType, List.nil(), csym);
920 ctype.supertype_field = syms.objectType;
921 ctype.interfaces_field = target.isIntersection() ?
922 directSupertypes(target) :
923 List.of(target);
924 csym.type = ctype;
925 csym.sourcefile = ((ClassSymbol)csym.owner).sourcefile;
926 return csym;
927 }
928
929 /**
930 * Find the minimal set of methods that are overridden by the functional
931 * descriptor in 'origin'. All returned methods are assumed to have different
932 * erased signatures.
933 */
934 public List<Symbol> functionalInterfaceBridges(TypeSymbol origin) {
935 Assert.check(isFunctionalInterface(origin));
936 Symbol descSym = findDescriptorSymbol(origin);
937 CompoundScope members = membersClosure(origin.type, false);
938 ListBuffer<Symbol> overridden = new ListBuffer<>();
939 outer: for (Symbol m2 : members.getSymbolsByName(descSym.name, bridgeFilter)) {
940 if (m2 == descSym) continue;
941 else if (descSym.overrides(m2, origin, Types.this, false)) {
942 for (Symbol m3 : overridden) {
943 if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) ||
944 (m3.overrides(m2, origin, Types.this, false) &&
945 (pendingBridges((ClassSymbol)origin, m3.enclClass()) ||
946 (((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) {
947 continue outer;
948 }
949 }
950 overridden.add(m2);
951 }
952 }
953 return overridden.toList();
954 }
955 //where
956 // Use anonymous class instead of lambda expression intentionally,
957 // because the variable `names` has modifier: final.
958 private Predicate<Symbol> bridgeFilter = new Predicate<Symbol>() {
959 public boolean test(Symbol t) {
960 return t.kind == MTH &&
961 t.name != names.init &&
962 t.name != names.clinit &&
963 (t.flags() & SYNTHETIC) == 0;
964 }
965 };
966
967 private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) {
968 //a symbol will be completed from a classfile if (a) symbol has
969 //an associated file object with CLASS kind and (b) the symbol has
970 //not been entered
971 if (origin.classfile != null &&
972 origin.classfile.getKind() == JavaFileObject.Kind.CLASS &&
973 enter.getEnv(origin) == null) {
974 return false;
975 }
976 if (origin == s) {
977 return true;
978 }
979 for (Type t : interfaces(origin.type)) {
980 if (pendingBridges((ClassSymbol)t.tsym, s)) {
981 return true;
982 }
983 }
984 return false;
985 }
986 // </editor-fold>
987
988 /**
989 * Scope filter used to skip methods that should be ignored (such as methods
990 * overridden by j.l.Object) during function interface conversion interface check
991 */
992 class DescriptorFilter implements Predicate<Symbol> {
993
994 TypeSymbol origin;
995
996 DescriptorFilter(TypeSymbol origin) {
997 this.origin = origin;
998 }
999
1000 @Override
1001 public boolean test(Symbol sym) {
1002 return sym.kind == MTH &&
1003 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
1004 !overridesObjectMethod(origin, sym) &&
1005 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
1006 }
1007 }
1008
1009 // <editor-fold defaultstate="collapsed" desc="isSubtype">
1010 /**
1011 * Is t an unchecked subtype of s?
1012 */
1013 public boolean isSubtypeUnchecked(Type t, Type s) {
1014 return isSubtypeUnchecked(t, s, noWarnings);
1015 }
1016 /**
1017 * Is t an unchecked subtype of s?
1018 */
1019 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
1020 boolean result = isSubtypeUncheckedInternal(t, s, true, warn);
1021 if (result) {
1022 checkUnsafeVarargsConversion(t, s, warn);
1023 }
1024 return result;
1025 }
1026 //where
1027 private boolean isSubtypeUncheckedInternal(Type t, Type s, boolean capture, Warner warn) {
1028 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
1029 if (((ArrayType)t).elemtype.isPrimitive()) {
1030 return isSameType(elemtype(t), elemtype(s));
1031 } else {
1032 return isSubtypeUncheckedInternal(elemtype(t), elemtype(s), false, warn);
1033 }
1034 } else if (isSubtype(t, s, capture)) {
1035 return true;
1036 } else if (t.hasTag(TYPEVAR)) {
1037 return isSubtypeUncheckedInternal(t.getUpperBound(), s, false, warn);
1038 } else if (!s.isRaw()) {
1039 Type t2 = asSuper(t, s.tsym);
1040 if (t2 != null && t2.isRaw()) {
1041 if (isReifiable(s)) {
1042 warn.silentWarn(LintCategory.UNCHECKED);
1043 } else {
1044 warn.warn(LintCategory.UNCHECKED);
1045 }
1046 return true;
1047 }
1048 }
1049 return false;
1050 }
1051
1052 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
1053 if (!t.hasTag(ARRAY) || isReifiable(t)) {
1054 return;
1055 }
1056 ArrayType from = (ArrayType)t;
1057 boolean shouldWarn = false;
1058 switch (s.getTag()) {
1059 case ARRAY:
1060 ArrayType to = (ArrayType)s;
1061 shouldWarn = from.isVarargs() &&
1062 !to.isVarargs() &&
1063 !isReifiable(from);
1064 break;
1065 case CLASS:
1066 shouldWarn = from.isVarargs();
1067 break;
1068 }
1069 if (shouldWarn) {
1070 warn.warn(LintCategory.VARARGS);
1071 }
1072 }
1073
1074 /**
1075 * Is t a subtype of s?<br>
1076 * (not defined for Method and ForAll types)
1077 */
1078 public final boolean isSubtype(Type t, Type s) {
1079 return isSubtype(t, s, true);
1080 }
1081 public final boolean isSubtypeNoCapture(Type t, Type s) {
1082 return isSubtype(t, s, false);
1083 }
1084 public boolean isSubtype(Type t, Type s, boolean capture) {
1085 if (t.equalsIgnoreMetadata(s))
1086 return true;
1087 if (s.isPartial())
1088 return isSuperType(s, t);
1089
1090 if (s.isCompound()) {
1091 for (Type s2 : interfaces(s).prepend(supertype(s))) {
1092 if (!isSubtype(t, s2, capture))
1093 return false;
1094 }
1095 return true;
1096 }
1097
1098 // Generally, if 's' is a lower-bounded type variable, recur on lower bound; but
1099 // for inference variables and intersections, we need to keep 's'
1100 // (see JLS 4.10.2 for intersections and 18.2.3 for inference vars)
1101 if (!t.hasTag(UNDETVAR) && !t.isCompound()) {
1102 // TODO: JDK-8039198, bounds checking sometimes passes in a wildcard as s
1103 Type lower = cvarLowerBound(wildLowerBound(s));
1104 if (s != lower && !lower.hasTag(BOT))
1105 return isSubtype(capture ? capture(t) : t, lower, false);
1106 }
1107
1108 return isSubtype.visit(capture ? capture(t) : t, s);
1109 }
1110 // where
1111 private TypeRelation isSubtype = new TypeRelation()
1112 {
1113 @Override
1114 public Boolean visitType(Type t, Type s) {
1115 switch (t.getTag()) {
1116 case BYTE:
1117 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
1118 case CHAR:
1119 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
1120 case SHORT: case INT: case LONG:
1121 case FLOAT: case DOUBLE:
1122 return t.getTag().isSubRangeOf(s.getTag());
1123 case BOOLEAN: case VOID:
1124 return t.hasTag(s.getTag());
1125 case TYPEVAR:
1126 return isSubtypeNoCapture(t.getUpperBound(), s);
1127 case BOT:
1128 return
1129 s.hasTag(BOT) || s.hasTag(CLASS) ||
1130 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
1131 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
1132 case NONE:
1133 return false;
1134 default:
1135 throw new AssertionError("isSubtype " + t.getTag());
1136 }
1137 }
1138
1139 private Set<TypePair> cache = new HashSet<>();
1140
1141 private boolean containsTypeRecursive(Type t, Type s) {
1142 TypePair pair = new TypePair(t, s);
1143 if (cache.add(pair)) {
1144 try {
1145 return containsType(t.getTypeArguments(),
1146 s.getTypeArguments());
1147 } finally {
1148 cache.remove(pair);
1149 }
1150 } else {
1151 return containsType(t.getTypeArguments(),
1152 rewriteSupers(s).getTypeArguments());
1153 }
1154 }
1155
1156 private Type rewriteSupers(Type t) {
1157 if (!t.isParameterized())
1158 return t;
1159 ListBuffer<Type> from = new ListBuffer<>();
1160 ListBuffer<Type> to = new ListBuffer<>();
1161 adaptSelf(t, from, to);
1162 if (from.isEmpty())
1163 return t;
1164 ListBuffer<Type> rewrite = new ListBuffer<>();
1165 boolean changed = false;
1166 for (Type orig : to.toList()) {
1167 Type s = rewriteSupers(orig);
1168 if (s.isSuperBound() && !s.isExtendsBound()) {
1169 s = new WildcardType(syms.objectType,
1170 BoundKind.UNBOUND,
1171 syms.boundClass,
1172 s.getMetadata());
1173 changed = true;
1174 } else if (s != orig) {
1175 s = new WildcardType(wildUpperBound(s),
1176 BoundKind.EXTENDS,
1177 syms.boundClass,
1178 s.getMetadata());
1179 changed = true;
1180 }
1181 rewrite.append(s);
1182 }
1183 if (changed)
1184 return subst(t.tsym.type, from.toList(), rewrite.toList());
1185 else
1186 return t;
1187 }
1188
1189 @Override
1190 public Boolean visitClassType(ClassType t, Type s) {
1191 Type sup = asSuper(t, s.tsym);
1192 if (sup == null) return false;
1193 // If t is an intersection, sup might not be a class type
1194 if (!sup.hasTag(CLASS)) return isSubtypeNoCapture(sup, s);
1195 return sup.tsym == s.tsym
1196 // Check type variable containment
1197 && (!s.isParameterized() || containsTypeRecursive(s, sup))
1198 && isSubtypeNoCapture(sup.getEnclosingType(),
1199 s.getEnclosingType());
1200 }
1201
1202 @Override
1203 public Boolean visitArrayType(ArrayType t, Type s) {
1204 if (s.hasTag(ARRAY)) {
1205 if (t.elemtype.isPrimitive())
1206 return isSameType(t.elemtype, elemtype(s));
1207 else
1208 return isSubtypeNoCapture(t.elemtype, elemtype(s));
1209 }
1210
1211 if (s.hasTag(CLASS)) {
1212 Name sname = s.tsym.getQualifiedName();
1213 return sname == names.java_lang_Object
1214 || sname == names.java_lang_Cloneable
1215 || sname == names.java_io_Serializable;
1216 }
1217
1218 return false;
1219 }
1220
1221 @Override
1222 public Boolean visitUndetVar(UndetVar t, Type s) {
1223 //todo: test against origin needed? or replace with substitution?
1224 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
1225 return true;
1226 } else if (s.hasTag(BOT)) {
1227 //if 's' is 'null' there's no instantiated type U for which
1228 //U <: s (but 'null' itself, which is not a valid type)
1229 return false;
1230 }
1231
1232 t.addBound(InferenceBound.UPPER, s, Types.this);
1233 return true;
1234 }
1235
1236 @Override
1237 public Boolean visitErrorType(ErrorType t, Type s) {
1238 return true;
1239 }
1240 };
1241
1242 /**
1243 * Is t a subtype of every type in given list `ts'?<br>
1244 * (not defined for Method and ForAll types)<br>
1245 * Allows unchecked conversions.
1246 */
1247 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
1248 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
1249 if (!isSubtypeUnchecked(t, l.head, warn))
1250 return false;
1251 return true;
1252 }
1253
1254 /**
1255 * Are corresponding elements of ts subtypes of ss? If lists are
1256 * of different length, return false.
1257 */
1258 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
1259 while (ts.tail != null && ss.tail != null
1260 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1261 isSubtype(ts.head, ss.head)) {
1262 ts = ts.tail;
1263 ss = ss.tail;
1264 }
1265 return ts.tail == null && ss.tail == null;
1266 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1267 }
1268
1269 /**
1270 * Are corresponding elements of ts subtypes of ss, allowing
1271 * unchecked conversions? If lists are of different length,
1272 * return false.
1273 **/
1274 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
1275 while (ts.tail != null && ss.tail != null
1276 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1277 isSubtypeUnchecked(ts.head, ss.head, warn)) {
1278 ts = ts.tail;
1279 ss = ss.tail;
1280 }
1281 return ts.tail == null && ss.tail == null;
1282 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1283 }
1284 // </editor-fold>
1285
1286 // <editor-fold defaultstate="collapsed" desc="isSuperType">
1287 /**
1288 * Is t a supertype of s?
1289 */
1290 public boolean isSuperType(Type t, Type s) {
1291 switch (t.getTag()) {
1292 case ERROR:
1293 return true;
1294 case UNDETVAR: {
1295 UndetVar undet = (UndetVar)t;
1296 if (t == s ||
1297 undet.qtype == s ||
1298 s.hasTag(ERROR) ||
1299 s.hasTag(BOT)) {
1300 return true;
1301 }
1302 undet.addBound(InferenceBound.LOWER, s, this);
1303 return true;
1304 }
1305 default:
1306 return isSubtype(s, t);
1307 }
1308 }
1309 // </editor-fold>
1310
1311 // <editor-fold defaultstate="collapsed" desc="isSameType">
1312 /**
1313 * Are corresponding elements of the lists the same type? If
1314 * lists are of different length, return false.
1315 */
1316 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
1317 while (ts.tail != null && ss.tail != null
1318 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1319 isSameType(ts.head, ss.head)) {
1320 ts = ts.tail;
1321 ss = ss.tail;
1322 }
1323 return ts.tail == null && ss.tail == null;
1324 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1325 }
1326
1327 /**
1328 * A polymorphic signature method (JLS 15.12.3) is a method that
1329 * (i) is declared in the java.lang.invoke.MethodHandle/VarHandle classes;
1330 * (ii) takes a single variable arity parameter;
1331 * (iii) whose declared type is Object[];
1332 * (iv) has any return type, Object signifying a polymorphic return type; and
1333 * (v) is native.
1334 */
1335 public boolean isSignaturePolymorphic(MethodSymbol msym) {
1336 List<Type> argtypes = msym.type.getParameterTypes();
1337 return (msym.flags_field & NATIVE) != 0 &&
1338 (msym.owner == syms.methodHandleType.tsym || msym.owner == syms.varHandleType.tsym) &&
1339 argtypes.length() == 1 &&
1340 argtypes.head.hasTag(TypeTag.ARRAY) &&
1341 ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym;
1342 }
1343
1344 /**
1345 * Is t the same type as s?
1346 */
1347 public boolean isSameType(Type t, Type s) {
1348 return isSameTypeVisitor.visit(t, s);
1349 }
1350 // where
1351
1352 /**
1353 * Type-equality relation - type variables are considered
1354 * equals if they share the same object identity.
1355 */
1356 TypeRelation isSameTypeVisitor = new TypeRelation() {
1357
1358 public Boolean visitType(Type t, Type s) {
1359 if (t.equalsIgnoreMetadata(s))
1360 return true;
1361
1362 if (s.isPartial())
1363 return visit(s, t);
1364
1365 switch (t.getTag()) {
1366 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1367 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
1368 return t.hasTag(s.getTag());
1369 case TYPEVAR: {
1370 if (s.hasTag(TYPEVAR)) {
1371 //type-substitution does not preserve type-var types
1372 //check that type var symbols and bounds are indeed the same
1373 return t == s;
1374 }
1375 else {
1376 //special case for s == ? super X, where upper(s) = u
1377 //check that u == t, where u has been set by Type.withTypeVar
1378 return s.isSuperBound() &&
1379 !s.isExtendsBound() &&
1380 visit(t, wildUpperBound(s));
1381 }
1382 }
1383 default:
1384 throw new AssertionError("isSameType " + t.getTag());
1385 }
1386 }
1387
1388 @Override
1389 public Boolean visitWildcardType(WildcardType t, Type s) {
1390 if (!s.hasTag(WILDCARD)) {
1391 return false;
1392 } else {
1393 WildcardType t2 = (WildcardType)s;
1394 return (t.kind == t2.kind || (t.isExtendsBound() && s.isExtendsBound())) &&
1395 isSameType(t.type, t2.type);
1396 }
1397 }
1398
1399 @Override
1400 public Boolean visitClassType(ClassType t, Type s) {
1401 if (t == s)
1402 return true;
1403
1404 if (s.isPartial())
1405 return visit(s, t);
1406
1407 if (s.isSuperBound() && !s.isExtendsBound())
1408 return visit(t, wildUpperBound(s)) && visit(t, wildLowerBound(s));
1409
1410 if (t.isCompound() && s.isCompound()) {
1411 if (!visit(supertype(t), supertype(s)))
1412 return false;
1413
1414 Map<Symbol,Type> tMap = new HashMap<>();
1415 for (Type ti : interfaces(t)) {
1416 tMap.put(ti.tsym, ti);
1417 }
1418 for (Type si : interfaces(s)) {
1419 if (!tMap.containsKey(si.tsym))
1420 return false;
1421 Type ti = tMap.remove(si.tsym);
1422 if (!visit(ti, si))
1423 return false;
1424 }
1425 return tMap.isEmpty();
1426 }
1427 return t.tsym == s.tsym
1428 && visit(t.getEnclosingType(), s.getEnclosingType())
1429 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
1430 }
1431
1432 @Override
1433 public Boolean visitArrayType(ArrayType t, Type s) {
1434 if (t == s)
1435 return true;
1436
1437 if (s.isPartial())
1438 return visit(s, t);
1439
1440 return s.hasTag(ARRAY)
1441 && containsTypeEquivalent(t.elemtype, elemtype(s));
1442 }
1443
1444 @Override
1445 public Boolean visitMethodType(MethodType t, Type s) {
1446 // isSameType for methods does not take thrown
1447 // exceptions into account!
1448 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
1449 }
1450
1451 @Override
1452 public Boolean visitPackageType(PackageType t, Type s) {
1453 return t == s;
1454 }
1455
1456 @Override
1457 public Boolean visitForAll(ForAll t, Type s) {
1458 if (!s.hasTag(FORALL)) {
1459 return false;
1460 }
1461
1462 ForAll forAll = (ForAll)s;
1463 return hasSameBounds(t, forAll)
1464 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1465 }
1466
1467 @Override
1468 public Boolean visitUndetVar(UndetVar t, Type s) {
1469 if (s.hasTag(WILDCARD)) {
1470 // FIXME, this might be leftovers from before capture conversion
1471 return false;
1472 }
1473
1474 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
1475 return true;
1476 }
1477
1478 t.addBound(InferenceBound.EQ, s, Types.this);
1479
1480 return true;
1481 }
1482
1483 @Override
1484 public Boolean visitErrorType(ErrorType t, Type s) {
1485 return true;
1486 }
1487 };
1488
1489 // </editor-fold>
1490
1491 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1492 public boolean containedBy(Type t, Type s) {
1493 switch (t.getTag()) {
1494 case UNDETVAR:
1495 if (s.hasTag(WILDCARD)) {
1496 UndetVar undetvar = (UndetVar)t;
1497 WildcardType wt = (WildcardType)s;
1498 switch(wt.kind) {
1499 case UNBOUND:
1500 break;
1501 case EXTENDS: {
1502 Type bound = wildUpperBound(s);
1503 undetvar.addBound(InferenceBound.UPPER, bound, this);
1504 break;
1505 }
1506 case SUPER: {
1507 Type bound = wildLowerBound(s);
1508 undetvar.addBound(InferenceBound.LOWER, bound, this);
1509 break;
1510 }
1511 }
1512 return true;
1513 } else {
1514 return isSameType(t, s);
1515 }
1516 case ERROR:
1517 return true;
1518 default:
1519 return containsType(s, t);
1520 }
1521 }
1522
1523 boolean containsType(List<Type> ts, List<Type> ss) {
1524 while (ts.nonEmpty() && ss.nonEmpty()
1525 && containsType(ts.head, ss.head)) {
1526 ts = ts.tail;
1527 ss = ss.tail;
1528 }
1529 return ts.isEmpty() && ss.isEmpty();
1530 }
1531
1532 /**
1533 * Check if t contains s.
1534 *
1535 * <p>T contains S if:
1536 *
1537 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1538 *
1539 * <p>This relation is only used by ClassType.isSubtype(), that
1540 * is,
1541 *
1542 * <p>{@code C<S> <: C<T> if T contains S.}
1543 *
1544 * <p>Because of F-bounds, this relation can lead to infinite
1545 * recursion. Thus we must somehow break that recursion. Notice
1546 * that containsType() is only called from ClassType.isSubtype().
1547 * Since the arguments have already been checked against their
1548 * bounds, we know:
1549 *
1550 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1551 *
1552 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1553 *
1554 * @param t a type
1555 * @param s a type
1556 */
1557 public boolean containsType(Type t, Type s) {
1558 return containsType.visit(t, s);
1559 }
1560 // where
1561 private TypeRelation containsType = new TypeRelation() {
1562
1563 public Boolean visitType(Type t, Type s) {
1564 if (s.isPartial())
1565 return containedBy(s, t);
1566 else
1567 return isSameType(t, s);
1568 }
1569
1570 // void debugContainsType(WildcardType t, Type s) {
1571 // System.err.println();
1572 // System.err.format(" does %s contain %s?%n", t, s);
1573 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1574 // wildUpperBound(s), s, t, wildUpperBound(t),
1575 // t.isSuperBound()
1576 // || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t)));
1577 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1578 // wildLowerBound(t), t, s, wildLowerBound(s),
1579 // t.isExtendsBound()
1580 // || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s)));
1581 // System.err.println();
1582 // }
1583
1584 @Override
1585 public Boolean visitWildcardType(WildcardType t, Type s) {
1586 if (s.isPartial())
1587 return containedBy(s, t);
1588 else {
1589 // debugContainsType(t, s);
1590 return isSameWildcard(t, s)
1591 || isCaptureOf(s, t)
1592 || ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))) &&
1593 (t.isSuperBound() || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t))));
1594 }
1595 }
1596
1597 @Override
1598 public Boolean visitUndetVar(UndetVar t, Type s) {
1599 if (!s.hasTag(WILDCARD)) {
1600 return isSameType(t, s);
1601 } else {
1602 return false;
1603 }
1604 }
1605
1606 @Override
1607 public Boolean visitErrorType(ErrorType t, Type s) {
1608 return true;
1609 }
1610 };
1611
1612 public boolean isCaptureOf(Type s, WildcardType t) {
1613 if (!s.hasTag(TYPEVAR) || !((TypeVar)s).isCaptured())
1614 return false;
1615 return isSameWildcard(t, ((CapturedType)s).wildcard);
1616 }
1617
1618 public boolean isSameWildcard(WildcardType t, Type s) {
1619 if (!s.hasTag(WILDCARD))
1620 return false;
1621 WildcardType w = (WildcardType)s;
1622 return w.kind == t.kind && w.type == t.type;
1623 }
1624
1625 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1626 while (ts.nonEmpty() && ss.nonEmpty()
1627 && containsTypeEquivalent(ts.head, ss.head)) {
1628 ts = ts.tail;
1629 ss = ss.tail;
1630 }
1631 return ts.isEmpty() && ss.isEmpty();
1632 }
1633 // </editor-fold>
1634
1635 // <editor-fold defaultstate="collapsed" desc="isCastable">
1636 public boolean isCastable(Type t, Type s) {
1637 return isCastable(t, s, noWarnings);
1638 }
1639
1640 /**
1641 * Is t castable to s?<br>
1642 * s is assumed to be an erased type.<br>
1643 * (not defined for Method and ForAll types).
1644 */
1645 public boolean isCastable(Type t, Type s, Warner warn) {
1646 // if same type
1647 if (t == s)
1648 return true;
1649 // if one of the types is primitive
1650 if (t.isPrimitive() != s.isPrimitive()) {
1651 t = skipTypeVars(t, false);
1652 return (isConvertible(t, s, warn)
1653 || (s.isPrimitive() &&
1654 isSubtype(boxedClass(s).type, t)));
1655 }
1656 boolean result;
1657 if (warn != warnStack.head) {
1658 try {
1659 warnStack = warnStack.prepend(warn);
1660 checkUnsafeVarargsConversion(t, s, warn);
1661 result = isCastable.visit(t,s);
1662 } finally {
1663 warnStack = warnStack.tail;
1664 }
1665 } else {
1666 result = isCastable.visit(t,s);
1667 }
1668 if (result && t.hasTag(CLASS) && t.tsym.kind.matches(Kinds.KindSelector.TYP)
1669 && s.hasTag(CLASS) && s.tsym.kind.matches(Kinds.KindSelector.TYP)
1670 && (t.tsym.isSealed() || s.tsym.isSealed())) {
1671 return (t.isCompound() || s.isCompound()) ?
1672 true :
1673 !(new DisjointChecker().areDisjoint((ClassSymbol)t.tsym, (ClassSymbol)s.tsym));
1674 }
1675 return result;
1676 }
1677 // where
1678 class DisjointChecker {
1679 Set<Pair<ClassSymbol, ClassSymbol>> pairsSeen = new HashSet<>();
1680 private boolean areDisjoint(ClassSymbol ts, ClassSymbol ss) {
1681 Pair<ClassSymbol, ClassSymbol> newPair = new Pair<>(ts, ss);
1682 /* if we are seeing the same pair again then there is an issue with the sealed hierarchy
1683 * bail out, a detailed error will be reported downstream
1684 */
1685 if (!pairsSeen.add(newPair))
1686 return false;
1687 if (isSubtype(erasure(ts.type), erasure(ss.type))) {
1688 return false;
1689 }
1690 // if both are classes or both are interfaces, shortcut
1691 if (ts.isInterface() == ss.isInterface() && isSubtype(erasure(ss.type), erasure(ts.type))) {
1692 return false;
1693 }
1694 if (ts.isInterface() && !ss.isInterface()) {
1695 /* so ts is interface but ss is a class
1696 * an interface is disjoint from a class if the class is disjoint form the interface
1697 */
1698 return areDisjoint(ss, ts);
1699 }
1700 // a final class that is not subtype of ss is disjoint
1701 if (!ts.isInterface() && ts.isFinal()) {
1702 return true;
1703 }
1704 // if at least one is sealed
1705 if (ts.isSealed() || ss.isSealed()) {
1706 // permitted subtypes have to be disjoint with the other symbol
1707 ClassSymbol sealedOne = ts.isSealed() ? ts : ss;
1708 ClassSymbol other = sealedOne == ts ? ss : ts;
1709 return sealedOne.getPermittedSubclasses().stream().allMatch(type -> areDisjoint((ClassSymbol)type.tsym, other));
1710 }
1711 return false;
1712 }
1713 }
1714
1715 private TypeRelation isCastable = new TypeRelation() {
1716
1717 public Boolean visitType(Type t, Type s) {
1718 if (s.hasTag(ERROR) || t.hasTag(NONE))
1719 return true;
1720
1721 switch (t.getTag()) {
1722 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1723 case DOUBLE:
1724 return s.isNumeric();
1725 case BOOLEAN:
1726 return s.hasTag(BOOLEAN);
1727 case VOID:
1728 return false;
1729 case BOT:
1730 return isSubtype(t, s);
1731 default:
1732 throw new AssertionError();
1733 }
1734 }
1735
1736 @Override
1737 public Boolean visitWildcardType(WildcardType t, Type s) {
1738 return isCastable(wildUpperBound(t), s, warnStack.head);
1739 }
1740
1741 @Override
1742 public Boolean visitClassType(ClassType t, Type s) {
1743 if (s.hasTag(ERROR) || s.hasTag(BOT))
1744 return true;
1745
1746 if (s.hasTag(TYPEVAR)) {
1747 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1748 warnStack.head.warn(LintCategory.UNCHECKED);
1749 return true;
1750 } else {
1751 return false;
1752 }
1753 }
1754
1755 if (t.isCompound() || s.isCompound()) {
1756 return !t.isCompound() ?
1757 visitCompoundType((ClassType)s, t, true) :
1758 visitCompoundType(t, s, false);
1759 }
1760
1761 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) {
1762 boolean upcast;
1763 if ((upcast = isSubtype(erasure(t), erasure(s)))
1764 || isSubtype(erasure(s), erasure(t))) {
1765 if (!upcast && s.hasTag(ARRAY)) {
1766 if (!isReifiable(s))
1767 warnStack.head.warn(LintCategory.UNCHECKED);
1768 return true;
1769 } else if (s.isRaw()) {
1770 return true;
1771 } else if (t.isRaw()) {
1772 if (!isUnbounded(s))
1773 warnStack.head.warn(LintCategory.UNCHECKED);
1774 return true;
1775 }
1776 // Assume |a| <: |b|
1777 final Type a = upcast ? t : s;
1778 final Type b = upcast ? s : t;
1779 final boolean HIGH = true;
1780 final boolean LOW = false;
1781 final boolean DONT_REWRITE_TYPEVARS = false;
1782 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1783 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1784 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1785 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1786 Type lowSub = asSub(bLow, aLow.tsym);
1787 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1788 if (highSub == null) {
1789 final boolean REWRITE_TYPEVARS = true;
1790 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1791 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1792 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1793 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1794 lowSub = asSub(bLow, aLow.tsym);
1795 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1796 }
1797 if (highSub != null) {
1798 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1799 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1800 }
1801 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1802 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1803 && !disjointTypes(aLow.allparams(), highSub.allparams())
1804 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1805 if (upcast ? giveWarning(a, b) :
1806 giveWarning(b, a))
1807 warnStack.head.warn(LintCategory.UNCHECKED);
1808 return true;
1809 }
1810 }
1811 if (isReifiable(s))
1812 return isSubtypeUnchecked(a, b);
1813 else
1814 return isSubtypeUnchecked(a, b, warnStack.head);
1815 }
1816
1817 // Sidecast
1818 if (s.hasTag(CLASS)) {
1819 if ((s.tsym.flags() & INTERFACE) != 0) {
1820 return ((t.tsym.flags() & FINAL) == 0)
1821 ? sideCast(t, s, warnStack.head)
1822 : sideCastFinal(t, s, warnStack.head);
1823 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1824 return ((s.tsym.flags() & FINAL) == 0)
1825 ? sideCast(t, s, warnStack.head)
1826 : sideCastFinal(t, s, warnStack.head);
1827 } else {
1828 // unrelated class types
1829 return false;
1830 }
1831 }
1832 }
1833 return false;
1834 }
1835
1836 boolean visitCompoundType(ClassType ct, Type s, boolean reverse) {
1837 Warner warn = noWarnings;
1838 for (Type c : directSupertypes(ct)) {
1839 warn.clear();
1840 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1841 return false;
1842 }
1843 if (warn.hasLint(LintCategory.UNCHECKED))
1844 warnStack.head.warn(LintCategory.UNCHECKED);
1845 return true;
1846 }
1847
1848 @Override
1849 public Boolean visitArrayType(ArrayType t, Type s) {
1850 switch (s.getTag()) {
1851 case ERROR:
1852 case BOT:
1853 return true;
1854 case TYPEVAR:
1855 if (isCastable(s, t, noWarnings)) {
1856 warnStack.head.warn(LintCategory.UNCHECKED);
1857 return true;
1858 } else {
1859 return false;
1860 }
1861 case CLASS:
1862 return isSubtype(t, s);
1863 case ARRAY:
1864 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1865 return elemtype(t).hasTag(elemtype(s).getTag());
1866 } else {
1867 return isCastable(elemtype(t), elemtype(s), warnStack.head);
1868 }
1869 default:
1870 return false;
1871 }
1872 }
1873
1874 @Override
1875 public Boolean visitTypeVar(TypeVar t, Type s) {
1876 switch (s.getTag()) {
1877 case ERROR:
1878 case BOT:
1879 return true;
1880 case TYPEVAR:
1881 if (isSubtype(t, s)) {
1882 return true;
1883 } else if (isCastable(t.getUpperBound(), s, noWarnings)) {
1884 warnStack.head.warn(LintCategory.UNCHECKED);
1885 return true;
1886 } else {
1887 return false;
1888 }
1889 default:
1890 return isCastable(t.getUpperBound(), s, warnStack.head);
1891 }
1892 }
1893
1894 @Override
1895 public Boolean visitErrorType(ErrorType t, Type s) {
1896 return true;
1897 }
1898 };
1899 // </editor-fold>
1900
1901 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1902 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1903 while (ts.tail != null && ss.tail != null) {
1904 if (disjointType(ts.head, ss.head)) return true;
1905 ts = ts.tail;
1906 ss = ss.tail;
1907 }
1908 return false;
1909 }
1910
1911 /**
1912 * Two types or wildcards are considered disjoint if it can be
1913 * proven that no type can be contained in both. It is
1914 * conservative in that it is allowed to say that two types are
1915 * not disjoint, even though they actually are.
1916 *
1917 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1918 * {@code X} and {@code Y} are not disjoint.
1919 */
1920 public boolean disjointType(Type t, Type s) {
1921 return disjointType.visit(t, s);
1922 }
1923 // where
1924 private TypeRelation disjointType = new TypeRelation() {
1925
1926 private Set<TypePair> cache = new HashSet<>();
1927
1928 @Override
1929 public Boolean visitType(Type t, Type s) {
1930 if (s.hasTag(WILDCARD))
1931 return visit(s, t);
1932 else
1933 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1934 }
1935
1936 private boolean isCastableRecursive(Type t, Type s) {
1937 TypePair pair = new TypePair(t, s);
1938 if (cache.add(pair)) {
1939 try {
1940 return Types.this.isCastable(t, s);
1941 } finally {
1942 cache.remove(pair);
1943 }
1944 } else {
1945 return true;
1946 }
1947 }
1948
1949 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1950 TypePair pair = new TypePair(t, s);
1951 if (cache.add(pair)) {
1952 try {
1953 return Types.this.notSoftSubtype(t, s);
1954 } finally {
1955 cache.remove(pair);
1956 }
1957 } else {
1958 return false;
1959 }
1960 }
1961
1962 @Override
1963 public Boolean visitWildcardType(WildcardType t, Type s) {
1964 if (t.isUnbound())
1965 return false;
1966
1967 if (!s.hasTag(WILDCARD)) {
1968 if (t.isExtendsBound())
1969 return notSoftSubtypeRecursive(s, t.type);
1970 else
1971 return notSoftSubtypeRecursive(t.type, s);
1972 }
1973
1974 if (s.isUnbound())
1975 return false;
1976
1977 if (t.isExtendsBound()) {
1978 if (s.isExtendsBound())
1979 return !isCastableRecursive(t.type, wildUpperBound(s));
1980 else if (s.isSuperBound())
1981 return notSoftSubtypeRecursive(wildLowerBound(s), t.type);
1982 } else if (t.isSuperBound()) {
1983 if (s.isExtendsBound())
1984 return notSoftSubtypeRecursive(t.type, wildUpperBound(s));
1985 }
1986 return false;
1987 }
1988 };
1989 // </editor-fold>
1990
1991 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds">
1992 public List<Type> cvarLowerBounds(List<Type> ts) {
1993 return ts.map(cvarLowerBoundMapping);
1994 }
1995 private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() {
1996 @Override
1997 public Type visitCapturedType(CapturedType t, Void _unused) {
1998 return cvarLowerBound(t);
1999 }
2000 };
2001 // </editor-fold>
2002
2003 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
2004 /**
2005 * This relation answers the question: is impossible that
2006 * something of type `t' can be a subtype of `s'? This is
2007 * different from the question "is `t' not a subtype of `s'?"
2008 * when type variables are involved: Integer is not a subtype of T
2009 * where {@code <T extends Number>} but it is not true that Integer cannot
2010 * possibly be a subtype of T.
2011 */
2012 public boolean notSoftSubtype(Type t, Type s) {
2013 if (t == s) return false;
2014 if (t.hasTag(TYPEVAR)) {
2015 TypeVar tv = (TypeVar) t;
2016 return !isCastable(tv.getUpperBound(),
2017 relaxBound(s),
2018 noWarnings);
2019 }
2020 if (!s.hasTag(WILDCARD))
2021 s = cvarUpperBound(s);
2022
2023 return !isSubtype(t, relaxBound(s));
2024 }
2025
2026 private Type relaxBound(Type t) {
2027 return (t.hasTag(TYPEVAR)) ?
2028 rewriteQuantifiers(skipTypeVars(t, false), true, true) :
2029 t;
2030 }
2031 // </editor-fold>
2032
2033 // <editor-fold defaultstate="collapsed" desc="isReifiable">
2034 public boolean isReifiable(Type t) {
2035 return isReifiable.visit(t);
2036 }
2037 // where
2038 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
2039
2040 public Boolean visitType(Type t, Void ignored) {
2041 return true;
2042 }
2043
2044 @Override
2045 public Boolean visitClassType(ClassType t, Void ignored) {
2046 if (t.isCompound())
2047 return false;
2048 else {
2049 if (!t.isParameterized())
2050 return true;
2051
2052 for (Type param : t.allparams()) {
2053 if (!param.isUnbound())
2054 return false;
2055 }
2056 return true;
2057 }
2058 }
2059
2060 @Override
2061 public Boolean visitArrayType(ArrayType t, Void ignored) {
2062 return visit(t.elemtype);
2063 }
2064
2065 @Override
2066 public Boolean visitTypeVar(TypeVar t, Void ignored) {
2067 return false;
2068 }
2069 };
2070 // </editor-fold>
2071
2072 // <editor-fold defaultstate="collapsed" desc="Array Utils">
2073 public boolean isArray(Type t) {
2074 while (t.hasTag(WILDCARD))
2075 t = wildUpperBound(t);
2076 return t.hasTag(ARRAY);
2077 }
2078
2079 /**
2080 * The element type of an array.
2081 */
2082 public Type elemtype(Type t) {
2083 switch (t.getTag()) {
2084 case WILDCARD:
2085 return elemtype(wildUpperBound(t));
2086 case ARRAY:
2087 return ((ArrayType)t).elemtype;
2088 case FORALL:
2089 return elemtype(((ForAll)t).qtype);
2090 case ERROR:
2091 return t;
2092 default:
2093 return null;
2094 }
2095 }
2096
2097 public Type elemtypeOrType(Type t) {
2098 Type elemtype = elemtype(t);
2099 return elemtype != null ?
2100 elemtype :
2101 t;
2102 }
2103
2104 /**
2105 * Mapping to take element type of an arraytype
2106 */
2107 private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() {
2108 @Override
2109 public Type visitArrayType(ArrayType t, Void _unused) {
2110 return t.elemtype;
2111 }
2112
2113 @Override
2114 public Type visitTypeVar(TypeVar t, Void _unused) {
2115 return visit(skipTypeVars(t, false));
2116 }
2117 };
2118
2119 /**
2120 * The number of dimensions of an array type.
2121 */
2122 public int dimensions(Type t) {
2123 int result = 0;
2124 while (t.hasTag(ARRAY)) {
2125 result++;
2126 t = elemtype(t);
2127 }
2128 return result;
2129 }
2130
2131 /**
2132 * Returns an ArrayType with the component type t
2133 *
2134 * @param t The component type of the ArrayType
2135 * @return the ArrayType for the given component
2136 */
2137 public ArrayType makeArrayType(Type t) {
2138 return makeArrayType(t, 1);
2139 }
2140
2141 public ArrayType makeArrayType(Type t, int dimensions) {
2142 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) {
2143 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
2144 }
2145 ArrayType result = new ArrayType(t, syms.arrayClass);
2146 for (int i = 1; i < dimensions; i++) {
2147 result = new ArrayType(result, syms.arrayClass);
2148 }
2149 return result;
2150 }
2151 // </editor-fold>
2152
2153 // <editor-fold defaultstate="collapsed" desc="asSuper">
2154 /**
2155 * Return the (most specific) base type of t that starts with the
2156 * given symbol. If none exists, return null.
2157 *
2158 * Caveat Emptor: Since javac represents the class of all arrays with a singleton
2159 * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant,
2160 * this method could yield surprising answers when invoked on arrays. For example when
2161 * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null.
2162 *
2163 * @param t a type
2164 * @param sym a symbol
2165 */
2166 public Type asSuper(Type t, Symbol sym) {
2167 /* Some examples:
2168 *
2169 * (Enum<E>, Comparable) => Comparable<E>
2170 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind>
2171 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree
2172 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) =>
2173 * Iterable<capture#160 of ? extends c.s.s.d.DocTree>
2174 */
2175 if (sym.type == syms.objectType) { //optimization
2176 return syms.objectType;
2177 }
2178 return asSuper.visit(t, sym);
2179 }
2180 // where
2181 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
2182
2183 private Set<Symbol> seenTypes = new HashSet<>();
2184
2185 public Type visitType(Type t, Symbol sym) {
2186 return null;
2187 }
2188
2189 @Override
2190 public Type visitClassType(ClassType t, Symbol sym) {
2191 if (t.tsym == sym)
2192 return t;
2193
2194 Symbol c = t.tsym;
2195 if (!seenTypes.add(c)) {
2196 return null;
2197 }
2198 try {
2199 Type st = supertype(t);
2200 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) {
2201 Type x = asSuper(st, sym);
2202 if (x != null)
2203 return x;
2204 }
2205 if ((sym.flags() & INTERFACE) != 0) {
2206 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
2207 if (!l.head.hasTag(ERROR)) {
2208 Type x = asSuper(l.head, sym);
2209 if (x != null)
2210 return x;
2211 }
2212 }
2213 }
2214 return null;
2215 } finally {
2216 seenTypes.remove(c);
2217 }
2218 }
2219
2220 @Override
2221 public Type visitArrayType(ArrayType t, Symbol sym) {
2222 return isSubtype(t, sym.type) ? sym.type : null;
2223 }
2224
2225 @Override
2226 public Type visitTypeVar(TypeVar t, Symbol sym) {
2227 if (t.tsym == sym)
2228 return t;
2229 else
2230 return asSuper(t.getUpperBound(), sym);
2231 }
2232
2233 @Override
2234 public Type visitErrorType(ErrorType t, Symbol sym) {
2235 return t;
2236 }
2237 };
2238
2239 /**
2240 * Return the base type of t or any of its outer types that starts
2241 * with the given symbol. If none exists, return null.
2242 *
2243 * @param t a type
2244 * @param sym a symbol
2245 */
2246 public Type asOuterSuper(Type t, Symbol sym) {
2247 switch (t.getTag()) {
2248 case CLASS:
2249 do {
2250 Type s = asSuper(t, sym);
2251 if (s != null) return s;
2252 t = t.getEnclosingType();
2253 } while (t.hasTag(CLASS));
2254 return null;
2255 case ARRAY:
2256 return isSubtype(t, sym.type) ? sym.type : null;
2257 case TYPEVAR:
2258 return asSuper(t, sym);
2259 case ERROR:
2260 return t;
2261 default:
2262 return null;
2263 }
2264 }
2265
2266 /**
2267 * Return the base type of t or any of its enclosing types that
2268 * starts with the given symbol. If none exists, return null.
2269 *
2270 * @param t a type
2271 * @param sym a symbol
2272 */
2273 public Type asEnclosingSuper(Type t, Symbol sym) {
2274 switch (t.getTag()) {
2275 case CLASS:
2276 do {
2277 Type s = asSuper(t, sym);
2278 if (s != null) return s;
2279 Type outer = t.getEnclosingType();
2280 t = (outer.hasTag(CLASS)) ? outer :
2281 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
2282 Type.noType;
2283 } while (t.hasTag(CLASS));
2284 return null;
2285 case ARRAY:
2286 return isSubtype(t, sym.type) ? sym.type : null;
2287 case TYPEVAR:
2288 return asSuper(t, sym);
2289 case ERROR:
2290 return t;
2291 default:
2292 return null;
2293 }
2294 }
2295 // </editor-fold>
2296
2297 // <editor-fold defaultstate="collapsed" desc="memberType">
2298 /**
2299 * The type of given symbol, seen as a member of t.
2300 *
2301 * @param t a type
2302 * @param sym a symbol
2303 */
2304 public Type memberType(Type t, Symbol sym) {
2305 return (sym.flags() & STATIC) != 0
2306 ? sym.type
2307 : memberType.visit(t, sym);
2308 }
2309 // where
2310 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
2311
2312 public Type visitType(Type t, Symbol sym) {
2313 return sym.type;
2314 }
2315
2316 @Override
2317 public Type visitWildcardType(WildcardType t, Symbol sym) {
2318 return memberType(wildUpperBound(t), sym);
2319 }
2320
2321 @Override
2322 public Type visitClassType(ClassType t, Symbol sym) {
2323 Symbol owner = sym.owner;
2324 long flags = sym.flags();
2325 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
2326 Type base = asOuterSuper(t, owner);
2327 //if t is an intersection type T = CT & I1 & I2 ... & In
2328 //its supertypes CT, I1, ... In might contain wildcards
2329 //so we need to go through capture conversion
2330 base = t.isCompound() ? capture(base) : base;
2331 if (base != null) {
2332 List<Type> ownerParams = owner.type.allparams();
2333 List<Type> baseParams = base.allparams();
2334 if (ownerParams.nonEmpty()) {
2335 if (baseParams.isEmpty()) {
2336 // then base is a raw type
2337 return erasure(sym.type);
2338 } else {
2339 return subst(sym.type, ownerParams, baseParams);
2340 }
2341 }
2342 }
2343 }
2344 return sym.type;
2345 }
2346
2347 @Override
2348 public Type visitTypeVar(TypeVar t, Symbol sym) {
2349 return memberType(t.getUpperBound(), sym);
2350 }
2351
2352 @Override
2353 public Type visitErrorType(ErrorType t, Symbol sym) {
2354 return t;
2355 }
2356 };
2357 // </editor-fold>
2358
2359 // <editor-fold defaultstate="collapsed" desc="isAssignable">
2360 public boolean isAssignable(Type t, Type s) {
2361 return isAssignable(t, s, noWarnings);
2362 }
2363
2364 /**
2365 * Is t assignable to s?<br>
2366 * Equivalent to subtype except for constant values and raw
2367 * types.<br>
2368 * (not defined for Method and ForAll types)
2369 */
2370 public boolean isAssignable(Type t, Type s, Warner warn) {
2371 if (t.hasTag(ERROR))
2372 return true;
2373 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) {
2374 int value = ((Number)t.constValue()).intValue();
2375 switch (s.getTag()) {
2376 case BYTE:
2377 case CHAR:
2378 case SHORT:
2379 case INT:
2380 if (s.getTag().checkRange(value))
2381 return true;
2382 break;
2383 case CLASS:
2384 switch (unboxedType(s).getTag()) {
2385 case BYTE:
2386 case CHAR:
2387 case SHORT:
2388 return isAssignable(t, unboxedType(s), warn);
2389 }
2390 break;
2391 }
2392 }
2393 return isConvertible(t, s, warn);
2394 }
2395 // </editor-fold>
2396
2397 // <editor-fold defaultstate="collapsed" desc="erasure">
2398 /**
2399 * The erasure of t {@code |t|} -- the type that results when all
2400 * type parameters in t are deleted.
2401 */
2402 public Type erasure(Type t) {
2403 return eraseNotNeeded(t) ? t : erasure(t, false);
2404 }
2405 //where
2406 private boolean eraseNotNeeded(Type t) {
2407 // We don't want to erase primitive types and String type as that
2408 // operation is idempotent. Also, erasing these could result in loss
2409 // of information such as constant values attached to such types.
2410 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2411 }
2412
2413 private Type erasure(Type t, boolean recurse) {
2414 if (t.isPrimitive()) {
2415 return t; /* fast special case */
2416 } else {
2417 Type out = erasure.visit(t, recurse);
2418 return out;
2419 }
2420 }
2421 // where
2422 private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() {
2423 @SuppressWarnings("fallthrough")
2424 private Type combineMetadata(final Type s,
2425 final Type t) {
2426 if (t.getMetadata().nonEmpty()) {
2427 switch (s.getTag()) {
2428 case CLASS:
2429 if (s instanceof UnionClassType ||
2430 s instanceof IntersectionClassType) {
2431 return s;
2432 }
2433 //fall-through
2434 case BYTE, CHAR, SHORT, LONG, FLOAT, INT, DOUBLE, BOOLEAN,
2435 ARRAY, MODULE, TYPEVAR, WILDCARD, BOT:
2436 return s.dropMetadata(Annotations.class);
2437 case VOID, METHOD, PACKAGE, FORALL, DEFERRED,
2438 NONE, ERROR, UNKNOWN, UNDETVAR, UNINITIALIZED_THIS,
2439 UNINITIALIZED_OBJECT:
2440 return s;
2441 default:
2442 throw new AssertionError(s.getTag().name());
2443 }
2444 } else {
2445 return s;
2446 }
2447 }
2448
2449 public Type visitType(Type t, Boolean recurse) {
2450 if (t.isPrimitive())
2451 return t; /*fast special case*/
2452 else {
2453 //other cases already handled
2454 return combineMetadata(t, t);
2455 }
2456 }
2457
2458 @Override
2459 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2460 Type erased = erasure(wildUpperBound(t), recurse);
2461 return combineMetadata(erased, t);
2462 }
2463
2464 @Override
2465 public Type visitClassType(ClassType t, Boolean recurse) {
2466 Type erased = t.tsym.erasure(Types.this);
2467 if (recurse) {
2468 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym,
2469 t.dropMetadata(Annotations.class).getMetadata());
2470 return erased;
2471 } else {
2472 return combineMetadata(erased, t);
2473 }
2474 }
2475
2476 @Override
2477 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2478 Type erased = erasure(t.getUpperBound(), recurse);
2479 return combineMetadata(erased, t);
2480 }
2481 };
2482
2483 public List<Type> erasure(List<Type> ts) {
2484 return erasure.visit(ts, false);
2485 }
2486
2487 public Type erasureRecursive(Type t) {
2488 return erasure(t, true);
2489 }
2490
2491 public List<Type> erasureRecursive(List<Type> ts) {
2492 return erasure.visit(ts, true);
2493 }
2494 // </editor-fold>
2495
2496 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType">
2497 /**
2498 * Make an intersection type from non-empty list of types. The list should be ordered according to
2499 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion.
2500 * Hence, this version of makeIntersectionType may not be called during a classfile read.
2501 *
2502 * @param bounds the types from which the intersection type is formed
2503 */
2504 public IntersectionClassType makeIntersectionType(List<Type> bounds) {
2505 return makeIntersectionType(bounds, bounds.head.tsym.isInterface());
2506 }
2507
2508 /**
2509 * Make an intersection type from non-empty list of types. The list should be ordered according to
2510 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as
2511 * an extra parameter indicates as to whether all bounds are interfaces - in which case the
2512 * supertype is implicitly assumed to be 'Object'.
2513 *
2514 * @param bounds the types from which the intersection type is formed
2515 * @param allInterfaces are all bounds interface types?
2516 */
2517 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) {
2518 Assert.check(bounds.nonEmpty());
2519 Type firstExplicitBound = bounds.head;
2520 if (allInterfaces) {
2521 bounds = bounds.prepend(syms.objectType);
2522 }
2523 ClassSymbol bc =
2524 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2525 Type.moreInfo
2526 ? names.fromString(bounds.toString())
2527 : names.empty,
2528 null,
2529 syms.noSymbol);
2530 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces);
2531 bc.type = intersectionType;
2532 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
2533 syms.objectType : // error condition, recover
2534 erasure(firstExplicitBound);
2535 bc.members_field = WriteableScope.create(bc);
2536 return intersectionType;
2537 }
2538 // </editor-fold>
2539
2540 // <editor-fold defaultstate="collapsed" desc="supertype">
2541 public Type supertype(Type t) {
2542 return supertype.visit(t);
2543 }
2544 // where
2545 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2546
2547 public Type visitType(Type t, Void ignored) {
2548 // A note on wildcards: there is no good way to
2549 // determine a supertype for a lower-bounded wildcard.
2550 return Type.noType;
2551 }
2552
2553 @Override
2554 public Type visitClassType(ClassType t, Void ignored) {
2555 if (t.supertype_field == null) {
2556 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2557 // An interface has no superclass; its supertype is Object.
2558 if (t.isInterface())
2559 supertype = ((ClassType)t.tsym.type).supertype_field;
2560 if (t.supertype_field == null) {
2561 List<Type> actuals = classBound(t).allparams();
2562 List<Type> formals = t.tsym.type.allparams();
2563 if (t.hasErasedSupertypes()) {
2564 t.supertype_field = erasureRecursive(supertype);
2565 } else if (formals.nonEmpty()) {
2566 t.supertype_field = subst(supertype, formals, actuals);
2567 }
2568 else {
2569 t.supertype_field = supertype;
2570 }
2571 }
2572 }
2573 return t.supertype_field;
2574 }
2575
2576 /**
2577 * The supertype is always a class type. If the type
2578 * variable's bounds start with a class type, this is also
2579 * the supertype. Otherwise, the supertype is
2580 * java.lang.Object.
2581 */
2582 @Override
2583 public Type visitTypeVar(TypeVar t, Void ignored) {
2584 if (t.getUpperBound().hasTag(TYPEVAR) ||
2585 (!t.getUpperBound().isCompound() && !t.getUpperBound().isInterface())) {
2586 return t.getUpperBound();
2587 } else {
2588 return supertype(t.getUpperBound());
2589 }
2590 }
2591
2592 @Override
2593 public Type visitArrayType(ArrayType t, Void ignored) {
2594 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2595 return arraySuperType();
2596 else
2597 return new ArrayType(supertype(t.elemtype), t.tsym);
2598 }
2599
2600 @Override
2601 public Type visitErrorType(ErrorType t, Void ignored) {
2602 return Type.noType;
2603 }
2604 };
2605 // </editor-fold>
2606
2607 // <editor-fold defaultstate="collapsed" desc="interfaces">
2608 /**
2609 * Return the interfaces implemented by this class.
2610 */
2611 public List<Type> interfaces(Type t) {
2612 return interfaces.visit(t);
2613 }
2614 // where
2615 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2616
2617 public List<Type> visitType(Type t, Void ignored) {
2618 return List.nil();
2619 }
2620
2621 @Override
2622 public List<Type> visitClassType(ClassType t, Void ignored) {
2623 if (t.interfaces_field == null) {
2624 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2625 if (t.interfaces_field == null) {
2626 // If t.interfaces_field is null, then t must
2627 // be a parameterized type (not to be confused
2628 // with a generic type declaration).
2629 // Terminology:
2630 // Parameterized type: List<String>
2631 // Generic type declaration: class List<E> { ... }
2632 // So t corresponds to List<String> and
2633 // t.tsym.type corresponds to List<E>.
2634 // The reason t must be parameterized type is
2635 // that completion will happen as a side
2636 // effect of calling
2637 // ClassSymbol.getInterfaces. Since
2638 // t.interfaces_field is null after
2639 // completion, we can assume that t is not the
2640 // type of a class/interface declaration.
2641 Assert.check(t != t.tsym.type, t);
2642 List<Type> actuals = t.allparams();
2643 List<Type> formals = t.tsym.type.allparams();
2644 if (t.hasErasedSupertypes()) {
2645 t.interfaces_field = erasureRecursive(interfaces);
2646 } else if (formals.nonEmpty()) {
2647 t.interfaces_field = subst(interfaces, formals, actuals);
2648 }
2649 else {
2650 t.interfaces_field = interfaces;
2651 }
2652 }
2653 }
2654 return t.interfaces_field;
2655 }
2656
2657 @Override
2658 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2659 if (t.getUpperBound().isCompound())
2660 return interfaces(t.getUpperBound());
2661
2662 if (t.getUpperBound().isInterface())
2663 return List.of(t.getUpperBound());
2664
2665 return List.nil();
2666 }
2667 };
2668
2669 public List<Type> directSupertypes(Type t) {
2670 return directSupertypes.visit(t);
2671 }
2672 // where
2673 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() {
2674
2675 public List<Type> visitType(final Type type, final Void ignored) {
2676 if (!type.isIntersection()) {
2677 final Type sup = supertype(type);
2678 return (sup == Type.noType || sup == type || sup == null)
2679 ? interfaces(type)
2680 : interfaces(type).prepend(sup);
2681 } else {
2682 return ((IntersectionClassType)type).getExplicitComponents();
2683 }
2684 }
2685 };
2686
2687 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2688 for (Type i2 : interfaces(origin.type)) {
2689 if (isym == i2.tsym) return true;
2690 }
2691 return false;
2692 }
2693 // </editor-fold>
2694
2695 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2696 Map<Type,Boolean> isDerivedRawCache = new HashMap<>();
2697
2698 public boolean isDerivedRaw(Type t) {
2699 Boolean result = isDerivedRawCache.get(t);
2700 if (result == null) {
2701 result = isDerivedRawInternal(t);
2702 isDerivedRawCache.put(t, result);
2703 }
2704 return result;
2705 }
2706
2707 public boolean isDerivedRawInternal(Type t) {
2708 if (t.isErroneous())
2709 return false;
2710 return
2711 t.isRaw() ||
2712 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) ||
2713 isDerivedRaw(interfaces(t));
2714 }
2715
2716 public boolean isDerivedRaw(List<Type> ts) {
2717 List<Type> l = ts;
2718 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2719 return l.nonEmpty();
2720 }
2721 // </editor-fold>
2722
2723 // <editor-fold defaultstate="collapsed" desc="setBounds">
2724 /**
2725 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly,
2726 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise
2727 * the supertype is simply left null (in this case, the supertype is assumed to be the head of
2728 * the bound list passed as second argument). Note that this check might cause a symbol completion.
2729 * Hence, this version of setBounds may not be called during a classfile read.
2730 *
2731 * @param t a type variable
2732 * @param bounds the bounds, must be nonempty
2733 */
2734 public void setBounds(TypeVar t, List<Type> bounds) {
2735 setBounds(t, bounds, bounds.head.tsym.isInterface());
2736 }
2737
2738 /**
2739 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds.
2740 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds
2741 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'.
2742 *
2743 * @param t a type variable
2744 * @param bounds the bounds, must be nonempty
2745 * @param allInterfaces are all bounds interface types?
2746 */
2747 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2748 t.setUpperBound( bounds.tail.isEmpty() ?
2749 bounds.head :
2750 makeIntersectionType(bounds, allInterfaces) );
2751 t.rank_field = -1;
2752 }
2753 // </editor-fold>
2754
2755 // <editor-fold defaultstate="collapsed" desc="getBounds">
2756 /**
2757 * Return list of bounds of the given type variable.
2758 */
2759 public List<Type> getBounds(TypeVar t) {
2760 if (t.getUpperBound().hasTag(NONE))
2761 return List.nil();
2762 else if (t.getUpperBound().isErroneous() || !t.getUpperBound().isCompound())
2763 return List.of(t.getUpperBound());
2764 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2765 return interfaces(t).prepend(supertype(t));
2766 else
2767 // No superclass was given in bounds.
2768 // In this case, supertype is Object, erasure is first interface.
2769 return interfaces(t);
2770 }
2771 // </editor-fold>
2772
2773 // <editor-fold defaultstate="collapsed" desc="classBound">
2774 /**
2775 * If the given type is a (possibly selected) type variable,
2776 * return the bounding class of this type, otherwise return the
2777 * type itself.
2778 */
2779 public Type classBound(Type t) {
2780 return classBound.visit(t);
2781 }
2782 // where
2783 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2784
2785 public Type visitType(Type t, Void ignored) {
2786 return t;
2787 }
2788
2789 @Override
2790 public Type visitClassType(ClassType t, Void ignored) {
2791 Type outer1 = classBound(t.getEnclosingType());
2792 if (outer1 != t.getEnclosingType())
2793 return new ClassType(outer1, t.getTypeArguments(), t.tsym,
2794 t.getMetadata());
2795 else
2796 return t;
2797 }
2798
2799 @Override
2800 public Type visitTypeVar(TypeVar t, Void ignored) {
2801 return classBound(supertype(t));
2802 }
2803
2804 @Override
2805 public Type visitErrorType(ErrorType t, Void ignored) {
2806 return t;
2807 }
2808 };
2809 // </editor-fold>
2810
2811 // <editor-fold defaultstate="collapsed" desc="subsignature / override equivalence">
2812 /**
2813 * Returns true iff the first signature is a <em>subsignature</em>
2814 * of the other. This is <b>not</b> an equivalence
2815 * relation.
2816 *
2817 * @jls 8.4.2 Method Signature
2818 * @see #overrideEquivalent(Type t, Type s)
2819 * @param t first signature (possibly raw).
2820 * @param s second signature (could be subjected to erasure).
2821 * @return true if t is a subsignature of s.
2822 */
2823 public boolean isSubSignature(Type t, Type s) {
2824 return hasSameArgs(t, s, true) || hasSameArgs(t, erasure(s), true);
2825 }
2826
2827 /**
2828 * Returns true iff these signatures are related by <em>override
2829 * equivalence</em>. This is the natural extension of
2830 * isSubSignature to an equivalence relation.
2831 *
2832 * @jls 8.4.2 Method Signature
2833 * @see #isSubSignature(Type t, Type s)
2834 * @param t a signature (possible raw, could be subjected to
2835 * erasure).
2836 * @param s a signature (possible raw, could be subjected to
2837 * erasure).
2838 * @return true if either argument is a subsignature of the other.
2839 */
2840 public boolean overrideEquivalent(Type t, Type s) {
2841 return hasSameArgs(t, s) ||
2842 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2843 }
2844
2845 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2846 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) {
2847 if (msym.overrides(sym, origin, Types.this, true)) {
2848 return true;
2849 }
2850 }
2851 return false;
2852 }
2853
2854 /**
2855 * This enum defines the strategy for implementing most specific return type check
2856 * during the most specific and functional interface checks.
2857 */
2858 public enum MostSpecificReturnCheck {
2859 /**
2860 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling
2861 * method type variables (if either method is generic) and (ii) subtyping should be replaced
2862 * by type-equivalence for primitives. This is essentially an inlined version of
2863 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been
2864 * replaced with a strict subtyping check.
2865 */
2866 BASIC() {
2867 @Override
2868 public boolean test(Type mt1, Type mt2, Types types) {
2869 List<Type> tvars = mt1.getTypeArguments();
2870 List<Type> svars = mt2.getTypeArguments();
2871 Type t = mt1.getReturnType();
2872 Type s = types.subst(mt2.getReturnType(), svars, tvars);
2873 return types.isSameType(t, s) ||
2874 !t.isPrimitive() &&
2875 !s.isPrimitive() &&
2876 types.isSubtype(t, s);
2877 }
2878 },
2879 /**
2880 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2.
2881 */
2882 RTS() {
2883 @Override
2884 public boolean test(Type mt1, Type mt2, Types types) {
2885 return types.returnTypeSubstitutable(mt1, mt2);
2886 }
2887 };
2888
2889 public abstract boolean test(Type mt1, Type mt2, Types types);
2890 }
2891
2892 /**
2893 * Merge multiple abstract methods. The preferred method is a method that is a subsignature
2894 * of all the other signatures and whose return type is more specific {@link MostSpecificReturnCheck}.
2895 * The resulting preferred method has a throws clause that is the intersection of the merged
2896 * methods' clauses.
2897 */
2898 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) {
2899 //first check for preconditions
2900 boolean shouldErase = false;
2901 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes();
2902 for (Symbol s : ambiguousInOrder) {
2903 if ((s.flags() & ABSTRACT) == 0 ||
2904 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) {
2905 return Optional.empty();
2906 } else if (s.type.hasTag(FORALL)) {
2907 shouldErase = true;
2908 }
2909 }
2910 //then merge abstracts
2911 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) {
2912 outer: for (Symbol s : ambiguousInOrder) {
2913 Type mt = memberType(site, s);
2914 List<Type> allThrown = mt.getThrownTypes();
2915 for (Symbol s2 : ambiguousInOrder) {
2916 if (s != s2) {
2917 Type mt2 = memberType(site, s2);
2918 if (!isSubSignature(mt, mt2) ||
2919 !mostSpecificReturnCheck.test(mt, mt2, this)) {
2920 //ambiguity cannot be resolved
2921 continue outer;
2922 } else {
2923 List<Type> thrownTypes2 = mt2.getThrownTypes();
2924 if (!mt.hasTag(FORALL) && shouldErase) {
2925 thrownTypes2 = erasure(thrownTypes2);
2926 } else if (mt.hasTag(FORALL)) {
2927 //subsignature implies that if most specific is generic, then all other
2928 //methods are too
2929 Assert.check(mt2.hasTag(FORALL));
2930 // if both are generic methods, adjust thrown types ahead of intersection computation
2931 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments());
2932 }
2933 allThrown = chk.intersect(allThrown, thrownTypes2);
2934 }
2935 }
2936 }
2937 return (allThrown == mt.getThrownTypes()) ?
2938 Optional.of(s) :
2939 Optional.of(new MethodSymbol(
2940 s.flags(),
2941 s.name,
2942 createMethodTypeWithThrown(s.type, allThrown),
2943 s.owner) {
2944 @Override
2945 public Symbol baseSymbol() {
2946 return s;
2947 }
2948 });
2949 }
2950 }
2951 return Optional.empty();
2952 }
2953
2954 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2955 class ImplementationCache {
2956
2957 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>();
2958
2959 class Entry {
2960 final MethodSymbol cachedImpl;
2961 final Predicate<Symbol> implFilter;
2962 final boolean checkResult;
2963 final int prevMark;
2964
2965 public Entry(MethodSymbol cachedImpl,
2966 Predicate<Symbol> scopeFilter,
2967 boolean checkResult,
2968 int prevMark) {
2969 this.cachedImpl = cachedImpl;
2970 this.implFilter = scopeFilter;
2971 this.checkResult = checkResult;
2972 this.prevMark = prevMark;
2973 }
2974
2975 boolean matches(Predicate<Symbol> scopeFilter, boolean checkResult, int mark) {
2976 return this.implFilter == scopeFilter &&
2977 this.checkResult == checkResult &&
2978 this.prevMark == mark;
2979 }
2980 }
2981
2982 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2983 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2984 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2985 if (cache == null) {
2986 cache = new HashMap<>();
2987 _map.put(ms, new SoftReference<>(cache));
2988 }
2989 Entry e = cache.get(origin);
2990 CompoundScope members = membersClosure(origin.type, true);
2991 if (e == null ||
2992 !e.matches(implFilter, checkResult, members.getMark())) {
2993 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2994 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2995 return impl;
2996 }
2997 else {
2998 return e.cachedImpl;
2999 }
3000 }
3001
3002 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
3003 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
3004 t = skipTypeVars(t, false);
3005 TypeSymbol c = t.tsym;
3006 Symbol bestSoFar = null;
3007 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) {
3008 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) {
3009 bestSoFar = sym;
3010 if ((sym.flags() & ABSTRACT) == 0) {
3011 //if concrete impl is found, exit immediately
3012 break;
3013 }
3014 }
3015 }
3016 if (bestSoFar != null) {
3017 //return either the (only) concrete implementation or the first abstract one
3018 return (MethodSymbol)bestSoFar;
3019 }
3020 }
3021 return null;
3022 }
3023 }
3024
3025 private ImplementationCache implCache = new ImplementationCache();
3026
3027 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
3028 return implCache.get(ms, origin, checkResult, implFilter);
3029 }
3030 // </editor-fold>
3031
3032 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
3033 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> {
3034
3035 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>();
3036
3037 Set<TypeSymbol> seenTypes = new HashSet<>();
3038
3039 class MembersScope extends CompoundScope {
3040
3041 CompoundScope scope;
3042
3043 public MembersScope(CompoundScope scope) {
3044 super(scope.owner);
3045 this.scope = scope;
3046 }
3047
3048 Predicate<Symbol> combine(Predicate<Symbol> sf) {
3049 return s -> !s.owner.isInterface() && (sf == null || sf.test(s));
3050 }
3051
3052 @Override
3053 public Iterable<Symbol> getSymbols(Predicate<Symbol> sf, LookupKind lookupKind) {
3054 return scope.getSymbols(combine(sf), lookupKind);
3055 }
3056
3057 @Override
3058 public Iterable<Symbol> getSymbolsByName(Name name, Predicate<Symbol> sf, LookupKind lookupKind) {
3059 return scope.getSymbolsByName(name, combine(sf), lookupKind);
3060 }
3061
3062 @Override
3063 public int getMark() {
3064 return scope.getMark();
3065 }
3066 }
3067
3068 CompoundScope nilScope;
3069
3070 /** members closure visitor methods **/
3071
3072 public CompoundScope visitType(Type t, Void _unused) {
3073 if (nilScope == null) {
3074 nilScope = new CompoundScope(syms.noSymbol);
3075 }
3076 return nilScope;
3077 }
3078
3079 @Override
3080 public CompoundScope visitClassType(ClassType t, Void _unused) {
3081 if (!seenTypes.add(t.tsym)) {
3082 //this is possible when an interface is implemented in multiple
3083 //superclasses, or when a class hierarchy is circular - in such
3084 //cases we don't need to recurse (empty scope is returned)
3085 return new CompoundScope(t.tsym);
3086 }
3087 try {
3088 seenTypes.add(t.tsym);
3089 ClassSymbol csym = (ClassSymbol)t.tsym;
3090 CompoundScope membersClosure = _map.get(csym);
3091 if (membersClosure == null) {
3092 membersClosure = new CompoundScope(csym);
3093 for (Type i : interfaces(t)) {
3094 membersClosure.prependSubScope(visit(i, null));
3095 }
3096 membersClosure.prependSubScope(visit(supertype(t), null));
3097 membersClosure.prependSubScope(csym.members());
3098 _map.put(csym, membersClosure);
3099 }
3100 return membersClosure;
3101 }
3102 finally {
3103 seenTypes.remove(t.tsym);
3104 }
3105 }
3106
3107 @Override
3108 public CompoundScope visitTypeVar(TypeVar t, Void _unused) {
3109 return visit(t.getUpperBound(), null);
3110 }
3111 }
3112
3113 private MembersClosureCache membersCache = new MembersClosureCache();
3114
3115 public CompoundScope membersClosure(Type site, boolean skipInterface) {
3116 CompoundScope cs = membersCache.visit(site, null);
3117 Assert.checkNonNull(cs, () -> "type " + site);
3118 return skipInterface ? membersCache.new MembersScope(cs) : cs;
3119 }
3120 // </editor-fold>
3121
3122
3123 /** Return first abstract member of class `sym'.
3124 */
3125 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) {
3126 try {
3127 return firstUnimplementedAbstractImpl(sym, sym);
3128 } catch (CompletionFailure ex) {
3129 chk.completionError(enter.getEnv(sym).tree.pos(), ex);
3130 return null;
3131 }
3132 }
3133 //where:
3134 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) {
3135 MethodSymbol undef = null;
3136 // Do not bother to search in classes that are not abstract,
3137 // since they cannot have abstract members.
3138 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
3139 Scope s = c.members();
3140 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
3141 if (sym.kind == MTH &&
3142 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
3143 MethodSymbol absmeth = (MethodSymbol)sym;
3144 MethodSymbol implmeth = absmeth.implementation(impl, this, true);
3145 if (implmeth == null || implmeth == absmeth) {
3146 //look for default implementations
3147 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head;
3148 if (prov != null && prov.overrides(absmeth, impl, this, true)) {
3149 implmeth = prov;
3150 }
3151 }
3152 if (implmeth == null || implmeth == absmeth) {
3153 undef = absmeth;
3154 break;
3155 }
3156 }
3157 }
3158 if (undef == null) {
3159 Type st = supertype(c.type);
3160 if (st.hasTag(CLASS))
3161 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym);
3162 }
3163 for (List<Type> l = interfaces(c.type);
3164 undef == null && l.nonEmpty();
3165 l = l.tail) {
3166 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym);
3167 }
3168 }
3169 return undef;
3170 }
3171
3172 public class CandidatesCache {
3173 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>();
3174
3175 class Entry {
3176 Type site;
3177 MethodSymbol msym;
3178
3179 Entry(Type site, MethodSymbol msym) {
3180 this.site = site;
3181 this.msym = msym;
3182 }
3183
3184 @Override
3185 public boolean equals(Object obj) {
3186 return (obj instanceof Entry entry)
3187 && entry.msym == msym
3188 && isSameType(site, entry.site);
3189 }
3190
3191 @Override
3192 public int hashCode() {
3193 return Types.this.hashCode(site) & ~msym.hashCode();
3194 }
3195 }
3196
3197 public List<MethodSymbol> get(Entry e) {
3198 return cache.get(e);
3199 }
3200
3201 public void put(Entry e, List<MethodSymbol> msymbols) {
3202 cache.put(e, msymbols);
3203 }
3204 }
3205
3206 public CandidatesCache candidatesCache = new CandidatesCache();
3207
3208 //where
3209 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
3210 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms);
3211 List<MethodSymbol> candidates = candidatesCache.get(e);
3212 if (candidates == null) {
3213 Predicate<Symbol> filter = new MethodFilter(ms, site);
3214 List<MethodSymbol> candidates2 = List.nil();
3215 for (Symbol s : membersClosure(site, false).getSymbols(filter)) {
3216 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
3217 return List.of((MethodSymbol)s);
3218 } else if (!candidates2.contains(s)) {
3219 candidates2 = candidates2.prepend((MethodSymbol)s);
3220 }
3221 }
3222 candidates = prune(candidates2);
3223 candidatesCache.put(e, candidates);
3224 }
3225 return candidates;
3226 }
3227
3228 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
3229 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>();
3230 for (MethodSymbol m1 : methods) {
3231 boolean isMin_m1 = true;
3232 for (MethodSymbol m2 : methods) {
3233 if (m1 == m2) continue;
3234 if (m2.owner != m1.owner &&
3235 asSuper(m2.owner.type, m1.owner) != null) {
3236 isMin_m1 = false;
3237 break;
3238 }
3239 }
3240 if (isMin_m1)
3241 methodsMin.append(m1);
3242 }
3243 return methodsMin.toList();
3244 }
3245 // where
3246 private class MethodFilter implements Predicate<Symbol> {
3247
3248 Symbol msym;
3249 Type site;
3250
3251 MethodFilter(Symbol msym, Type site) {
3252 this.msym = msym;
3253 this.site = site;
3254 }
3255
3256 @Override
3257 public boolean test(Symbol s) {
3258 return s.kind == MTH &&
3259 s.name == msym.name &&
3260 (s.flags() & SYNTHETIC) == 0 &&
3261 s.isInheritedIn(site.tsym, Types.this) &&
3262 overrideEquivalent(memberType(site, s), memberType(site, msym));
3263 }
3264 }
3265 // </editor-fold>
3266
3267 /**
3268 * Does t have the same arguments as s? It is assumed that both
3269 * types are (possibly polymorphic) method types. Monomorphic
3270 * method types "have the same arguments", if their argument lists
3271 * are equal. Polymorphic method types "have the same arguments",
3272 * if they have the same arguments after renaming all type
3273 * variables of one to corresponding type variables in the other,
3274 * where correspondence is by position in the type parameter list.
3275 */
3276 public boolean hasSameArgs(Type t, Type s) {
3277 return hasSameArgs(t, s, true);
3278 }
3279
3280 public boolean hasSameArgs(Type t, Type s, boolean strict) {
3281 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
3282 }
3283
3284 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
3285 return hasSameArgs.visit(t, s);
3286 }
3287 // where
3288 private class HasSameArgs extends TypeRelation {
3289
3290 boolean strict;
3291
3292 public HasSameArgs(boolean strict) {
3293 this.strict = strict;
3294 }
3295
3296 public Boolean visitType(Type t, Type s) {
3297 throw new AssertionError();
3298 }
3299
3300 @Override
3301 public Boolean visitMethodType(MethodType t, Type s) {
3302 return s.hasTag(METHOD)
3303 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
3304 }
3305
3306 @Override
3307 public Boolean visitForAll(ForAll t, Type s) {
3308 if (!s.hasTag(FORALL))
3309 return strict ? false : visitMethodType(t.asMethodType(), s);
3310
3311 ForAll forAll = (ForAll)s;
3312 return hasSameBounds(t, forAll)
3313 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
3314 }
3315
3316 @Override
3317 public Boolean visitErrorType(ErrorType t, Type s) {
3318 return false;
3319 }
3320 }
3321
3322 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
3323 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
3324
3325 // </editor-fold>
3326
3327 // <editor-fold defaultstate="collapsed" desc="subst">
3328 public List<Type> subst(List<Type> ts,
3329 List<Type> from,
3330 List<Type> to) {
3331 return ts.map(new Subst(from, to));
3332 }
3333
3334 /**
3335 * Substitute all occurrences of a type in `from' with the
3336 * corresponding type in `to' in 't'. Match lists `from' and `to'
3337 * from the right: If lists have different length, discard leading
3338 * elements of the longer list.
3339 */
3340 public Type subst(Type t, List<Type> from, List<Type> to) {
3341 return t.map(new Subst(from, to));
3342 }
3343
3344 private class Subst extends StructuralTypeMapping<Void> {
3345 List<Type> from;
3346 List<Type> to;
3347
3348 public Subst(List<Type> from, List<Type> to) {
3349 int fromLength = from.length();
3350 int toLength = to.length();
3351 while (fromLength > toLength) {
3352 fromLength--;
3353 from = from.tail;
3354 }
3355 while (fromLength < toLength) {
3356 toLength--;
3357 to = to.tail;
3358 }
3359 this.from = from;
3360 this.to = to;
3361 }
3362
3363 @Override
3364 public Type visitTypeVar(TypeVar t, Void ignored) {
3365 for (List<Type> from = this.from, to = this.to;
3366 from.nonEmpty();
3367 from = from.tail, to = to.tail) {
3368 if (t.equalsIgnoreMetadata(from.head)) {
3369 return to.head.withTypeVar(t);
3370 }
3371 }
3372 return t;
3373 }
3374
3375 @Override
3376 public Type visitClassType(ClassType t, Void ignored) {
3377 if (!t.isCompound()) {
3378 return super.visitClassType(t, ignored);
3379 } else {
3380 Type st = visit(supertype(t));
3381 List<Type> is = visit(interfaces(t), ignored);
3382 if (st == supertype(t) && is == interfaces(t))
3383 return t;
3384 else
3385 return makeIntersectionType(is.prepend(st));
3386 }
3387 }
3388
3389 @Override
3390 public Type visitWildcardType(WildcardType t, Void ignored) {
3391 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored);
3392 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) {
3393 t2.type = wildUpperBound(t2.type);
3394 }
3395 return t2;
3396 }
3397
3398 @Override
3399 public Type visitForAll(ForAll t, Void ignored) {
3400 if (Type.containsAny(to, t.tvars)) {
3401 //perform alpha-renaming of free-variables in 't'
3402 //if 'to' types contain variables that are free in 't'
3403 List<Type> freevars = newInstances(t.tvars);
3404 t = new ForAll(freevars,
3405 Types.this.subst(t.qtype, t.tvars, freevars));
3406 }
3407 List<Type> tvars1 = substBounds(t.tvars, from, to);
3408 Type qtype1 = visit(t.qtype);
3409 if (tvars1 == t.tvars && qtype1 == t.qtype) {
3410 return t;
3411 } else if (tvars1 == t.tvars) {
3412 return new ForAll(tvars1, qtype1) {
3413 @Override
3414 public boolean needsStripping() {
3415 return true;
3416 }
3417 };
3418 } else {
3419 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) {
3420 @Override
3421 public boolean needsStripping() {
3422 return true;
3423 }
3424 };
3425 }
3426 }
3427 }
3428
3429 public List<Type> substBounds(List<Type> tvars,
3430 List<Type> from,
3431 List<Type> to) {
3432 if (tvars.isEmpty())
3433 return tvars;
3434 ListBuffer<Type> newBoundsBuf = new ListBuffer<>();
3435 boolean changed = false;
3436 // calculate new bounds
3437 for (Type t : tvars) {
3438 TypeVar tv = (TypeVar) t;
3439 Type bound = subst(tv.getUpperBound(), from, to);
3440 if (bound != tv.getUpperBound())
3441 changed = true;
3442 newBoundsBuf.append(bound);
3443 }
3444 if (!changed)
3445 return tvars;
3446 ListBuffer<Type> newTvars = new ListBuffer<>();
3447 // create new type variables without bounds
3448 for (Type t : tvars) {
3449 newTvars.append(new TypeVar(t.tsym, null, syms.botType,
3450 t.getMetadata()));
3451 }
3452 // the new bounds should use the new type variables in place
3453 // of the old
3454 List<Type> newBounds = newBoundsBuf.toList();
3455 from = tvars;
3456 to = newTvars.toList();
3457 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
3458 newBounds.head = subst(newBounds.head, from, to);
3459 }
3460 newBounds = newBoundsBuf.toList();
3461 // set the bounds of new type variables to the new bounds
3462 for (Type t : newTvars.toList()) {
3463 TypeVar tv = (TypeVar) t;
3464 tv.setUpperBound( newBounds.head );
3465 newBounds = newBounds.tail;
3466 }
3467 return newTvars.toList();
3468 }
3469
3470 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
3471 Type bound1 = subst(t.getUpperBound(), from, to);
3472 if (bound1 == t.getUpperBound())
3473 return t;
3474 else {
3475 // create new type variable without bounds
3476 TypeVar tv = new TypeVar(t.tsym, null, syms.botType,
3477 t.getMetadata());
3478 // the new bound should use the new type variable in place
3479 // of the old
3480 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) );
3481 return tv;
3482 }
3483 }
3484 // </editor-fold>
3485
3486 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
3487 /**
3488 * Does t have the same bounds for quantified variables as s?
3489 */
3490 public boolean hasSameBounds(ForAll t, ForAll s) {
3491 List<Type> l1 = t.tvars;
3492 List<Type> l2 = s.tvars;
3493 while (l1.nonEmpty() && l2.nonEmpty() &&
3494 isSameType(l1.head.getUpperBound(),
3495 subst(l2.head.getUpperBound(),
3496 s.tvars,
3497 t.tvars))) {
3498 l1 = l1.tail;
3499 l2 = l2.tail;
3500 }
3501 return l1.isEmpty() && l2.isEmpty();
3502 }
3503 // </editor-fold>
3504
3505 // <editor-fold defaultstate="collapsed" desc="newInstances">
3506 /** Create new vector of type variables from list of variables
3507 * changing all recursive bounds from old to new list.
3508 */
3509 public List<Type> newInstances(List<Type> tvars) {
3510 List<Type> tvars1 = tvars.map(newInstanceFun);
3511 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
3512 TypeVar tv = (TypeVar) l.head;
3513 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) );
3514 }
3515 return tvars1;
3516 }
3517 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() {
3518 @Override
3519 public TypeVar visitTypeVar(TypeVar t, Void _unused) {
3520 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata());
3521 }
3522 };
3523 // </editor-fold>
3524
3525 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
3526 return original.accept(methodWithParameters, newParams);
3527 }
3528 // where
3529 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
3530 public Type visitType(Type t, List<Type> newParams) {
3531 throw new IllegalArgumentException("Not a method type: " + t);
3532 }
3533 public Type visitMethodType(MethodType t, List<Type> newParams) {
3534 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
3535 }
3536 public Type visitForAll(ForAll t, List<Type> newParams) {
3537 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
3538 }
3539 };
3540
3541 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
3542 return original.accept(methodWithThrown, newThrown);
3543 }
3544 // where
3545 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
3546 public Type visitType(Type t, List<Type> newThrown) {
3547 throw new IllegalArgumentException("Not a method type: " + t);
3548 }
3549 public Type visitMethodType(MethodType t, List<Type> newThrown) {
3550 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
3551 }
3552 public Type visitForAll(ForAll t, List<Type> newThrown) {
3553 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
3554 }
3555 };
3556
3557 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
3558 return original.accept(methodWithReturn, newReturn);
3559 }
3560 // where
3561 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
3562 public Type visitType(Type t, Type newReturn) {
3563 throw new IllegalArgumentException("Not a method type: " + t);
3564 }
3565 public Type visitMethodType(MethodType t, Type newReturn) {
3566 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) {
3567 @Override
3568 public Type baseType() {
3569 return t;
3570 }
3571 };
3572 }
3573 public Type visitForAll(ForAll t, Type newReturn) {
3574 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) {
3575 @Override
3576 public Type baseType() {
3577 return t;
3578 }
3579 };
3580 }
3581 };
3582
3583 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3584 public Type createErrorType(Type originalType) {
3585 return new ErrorType(originalType, syms.errSymbol);
3586 }
3587
3588 public Type createErrorType(ClassSymbol c, Type originalType) {
3589 return new ErrorType(c, originalType);
3590 }
3591
3592 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3593 return new ErrorType(name, container, originalType);
3594 }
3595 // </editor-fold>
3596
3597 // <editor-fold defaultstate="collapsed" desc="rank">
3598 /**
3599 * The rank of a class is the length of the longest path between
3600 * the class and java.lang.Object in the class inheritance
3601 * graph. Undefined for all but reference types.
3602 */
3603 public int rank(Type t) {
3604 switch(t.getTag()) {
3605 case CLASS: {
3606 ClassType cls = (ClassType)t;
3607 if (cls.rank_field < 0) {
3608 Name fullname = cls.tsym.getQualifiedName();
3609 if (fullname == names.java_lang_Object)
3610 cls.rank_field = 0;
3611 else {
3612 int r = rank(supertype(cls));
3613 for (List<Type> l = interfaces(cls);
3614 l.nonEmpty();
3615 l = l.tail) {
3616 if (rank(l.head) > r)
3617 r = rank(l.head);
3618 }
3619 cls.rank_field = r + 1;
3620 }
3621 }
3622 return cls.rank_field;
3623 }
3624 case TYPEVAR: {
3625 TypeVar tvar = (TypeVar)t;
3626 if (tvar.rank_field < 0) {
3627 int r = rank(supertype(tvar));
3628 for (List<Type> l = interfaces(tvar);
3629 l.nonEmpty();
3630 l = l.tail) {
3631 if (rank(l.head) > r) r = rank(l.head);
3632 }
3633 tvar.rank_field = r + 1;
3634 }
3635 return tvar.rank_field;
3636 }
3637 case ERROR:
3638 case NONE:
3639 return 0;
3640 default:
3641 throw new AssertionError();
3642 }
3643 }
3644 // </editor-fold>
3645
3646 /**
3647 * Helper method for generating a string representation of a given type
3648 * accordingly to a given locale
3649 */
3650 public String toString(Type t, Locale locale) {
3651 return Printer.createStandardPrinter(messages).visit(t, locale);
3652 }
3653
3654 /**
3655 * Helper method for generating a string representation of a given type
3656 * accordingly to a given locale
3657 */
3658 public String toString(Symbol t, Locale locale) {
3659 return Printer.createStandardPrinter(messages).visit(t, locale);
3660 }
3661
3662 // <editor-fold defaultstate="collapsed" desc="toString">
3663 /**
3664 * This toString is slightly more descriptive than the one on Type.
3665 *
3666 * @deprecated Types.toString(Type t, Locale l) provides better support
3667 * for localization
3668 */
3669 @Deprecated
3670 public String toString(Type t) {
3671 if (t.hasTag(FORALL)) {
3672 ForAll forAll = (ForAll)t;
3673 return typaramsString(forAll.tvars) + forAll.qtype;
3674 }
3675 return "" + t;
3676 }
3677 // where
3678 private String typaramsString(List<Type> tvars) {
3679 StringBuilder s = new StringBuilder();
3680 s.append('<');
3681 boolean first = true;
3682 for (Type t : tvars) {
3683 if (!first) s.append(", ");
3684 first = false;
3685 appendTyparamString(((TypeVar)t), s);
3686 }
3687 s.append('>');
3688 return s.toString();
3689 }
3690 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3691 buf.append(t);
3692 if (t.getUpperBound() == null ||
3693 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object)
3694 return;
3695 buf.append(" extends "); // Java syntax; no need for i18n
3696 Type bound = t.getUpperBound();
3697 if (!bound.isCompound()) {
3698 buf.append(bound);
3699 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3700 buf.append(supertype(t));
3701 for (Type intf : interfaces(t)) {
3702 buf.append('&');
3703 buf.append(intf);
3704 }
3705 } else {
3706 // No superclass was given in bounds.
3707 // In this case, supertype is Object, erasure is first interface.
3708 boolean first = true;
3709 for (Type intf : interfaces(t)) {
3710 if (!first) buf.append('&');
3711 first = false;
3712 buf.append(intf);
3713 }
3714 }
3715 }
3716 // </editor-fold>
3717
3718 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3719 /**
3720 * A cache for closures.
3721 *
3722 * <p>A closure is a list of all the supertypes and interfaces of
3723 * a class or interface type, ordered by ClassSymbol.precedes
3724 * (that is, subclasses come first, arbitrarily but fixed
3725 * otherwise).
3726 */
3727 private Map<Type,List<Type>> closureCache = new HashMap<>();
3728
3729 /**
3730 * Returns the closure of a class or interface type.
3731 */
3732 public List<Type> closure(Type t) {
3733 List<Type> cl = closureCache.get(t);
3734 if (cl == null) {
3735 Type st = supertype(t);
3736 if (!t.isCompound()) {
3737 if (st.hasTag(CLASS)) {
3738 cl = insert(closure(st), t);
3739 } else if (st.hasTag(TYPEVAR)) {
3740 cl = closure(st).prepend(t);
3741 } else {
3742 cl = List.of(t);
3743 }
3744 } else {
3745 cl = closure(supertype(t));
3746 }
3747 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3748 cl = union(cl, closure(l.head));
3749 closureCache.put(t, cl);
3750 }
3751 return cl;
3752 }
3753
3754 /**
3755 * Collect types into a new closure (using a {@code ClosureHolder})
3756 */
3757 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3758 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip),
3759 ClosureHolder::add,
3760 ClosureHolder::merge,
3761 ClosureHolder::closure);
3762 }
3763 //where
3764 class ClosureHolder {
3765 List<Type> closure;
3766 final boolean minClosure;
3767 final BiPredicate<Type, Type> shouldSkip;
3768
3769 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3770 this.closure = List.nil();
3771 this.minClosure = minClosure;
3772 this.shouldSkip = shouldSkip;
3773 }
3774
3775 void add(Type type) {
3776 closure = insert(closure, type, shouldSkip);
3777 }
3778
3779 ClosureHolder merge(ClosureHolder other) {
3780 closure = union(closure, other.closure, shouldSkip);
3781 return this;
3782 }
3783
3784 List<Type> closure() {
3785 return minClosure ? closureMin(closure) : closure;
3786 }
3787 }
3788
3789 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym;
3790
3791 /**
3792 * Insert a type in a closure
3793 */
3794 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) {
3795 if (cl.isEmpty()) {
3796 return cl.prepend(t);
3797 } else if (shouldSkip.test(t, cl.head)) {
3798 return cl;
3799 } else if (t.tsym.precedes(cl.head.tsym, this)) {
3800 return cl.prepend(t);
3801 } else {
3802 // t comes after head, or the two are unrelated
3803 return insert(cl.tail, t, shouldSkip).prepend(cl.head);
3804 }
3805 }
3806
3807 public List<Type> insert(List<Type> cl, Type t) {
3808 return insert(cl, t, basicClosureSkip);
3809 }
3810
3811 /**
3812 * Form the union of two closures
3813 */
3814 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) {
3815 if (cl1.isEmpty()) {
3816 return cl2;
3817 } else if (cl2.isEmpty()) {
3818 return cl1;
3819 } else if (shouldSkip.test(cl1.head, cl2.head)) {
3820 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
3821 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3822 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
3823 } else {
3824 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
3825 }
3826 }
3827
3828 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3829 return union(cl1, cl2, basicClosureSkip);
3830 }
3831
3832 /**
3833 * Intersect two closures
3834 */
3835 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3836 if (cl1 == cl2)
3837 return cl1;
3838 if (cl1.isEmpty() || cl2.isEmpty())
3839 return List.nil();
3840 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3841 return intersect(cl1.tail, cl2);
3842 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3843 return intersect(cl1, cl2.tail);
3844 if (isSameType(cl1.head, cl2.head))
3845 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3846 if (cl1.head.tsym == cl2.head.tsym &&
3847 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) {
3848 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3849 Type merge = merge(cl1.head,cl2.head);
3850 return intersect(cl1.tail, cl2.tail).prepend(merge);
3851 }
3852 if (cl1.head.isRaw() || cl2.head.isRaw())
3853 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3854 }
3855 return intersect(cl1.tail, cl2.tail);
3856 }
3857 // where
3858 class TypePair {
3859 final Type t1;
3860 final Type t2;;
3861
3862 TypePair(Type t1, Type t2) {
3863 this.t1 = t1;
3864 this.t2 = t2;
3865 }
3866 @Override
3867 public int hashCode() {
3868 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3869 }
3870 @Override
3871 public boolean equals(Object obj) {
3872 return (obj instanceof TypePair typePair)
3873 && isSameType(t1, typePair.t1)
3874 && isSameType(t2, typePair.t2);
3875 }
3876 }
3877 Set<TypePair> mergeCache = new HashSet<>();
3878 private Type merge(Type c1, Type c2) {
3879 ClassType class1 = (ClassType) c1;
3880 List<Type> act1 = class1.getTypeArguments();
3881 ClassType class2 = (ClassType) c2;
3882 List<Type> act2 = class2.getTypeArguments();
3883 ListBuffer<Type> merged = new ListBuffer<>();
3884 List<Type> typarams = class1.tsym.type.getTypeArguments();
3885
3886 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3887 if (containsType(act1.head, act2.head)) {
3888 merged.append(act1.head);
3889 } else if (containsType(act2.head, act1.head)) {
3890 merged.append(act2.head);
3891 } else {
3892 TypePair pair = new TypePair(c1, c2);
3893 Type m;
3894 if (mergeCache.add(pair)) {
3895 m = new WildcardType(lub(wildUpperBound(act1.head),
3896 wildUpperBound(act2.head)),
3897 BoundKind.EXTENDS,
3898 syms.boundClass);
3899 mergeCache.remove(pair);
3900 } else {
3901 m = new WildcardType(syms.objectType,
3902 BoundKind.UNBOUND,
3903 syms.boundClass);
3904 }
3905 merged.append(m.withTypeVar(typarams.head));
3906 }
3907 act1 = act1.tail;
3908 act2 = act2.tail;
3909 typarams = typarams.tail;
3910 }
3911 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3912 // There is no spec detailing how type annotations are to
3913 // be inherited. So set it to noAnnotations for now
3914 return new ClassType(class1.getEnclosingType(), merged.toList(),
3915 class1.tsym, List.nil());
3916 }
3917
3918 /**
3919 * Return the minimum type of a closure, a compound type if no
3920 * unique minimum exists.
3921 */
3922 private Type compoundMin(List<Type> cl) {
3923 if (cl.isEmpty()) return syms.objectType;
3924 List<Type> compound = closureMin(cl);
3925 if (compound.isEmpty())
3926 return null;
3927 else if (compound.tail.isEmpty())
3928 return compound.head;
3929 else
3930 return makeIntersectionType(compound);
3931 }
3932
3933 /**
3934 * Return the minimum types of a closure, suitable for computing
3935 * compoundMin or glb.
3936 */
3937 private List<Type> closureMin(List<Type> cl) {
3938 ListBuffer<Type> classes = new ListBuffer<>();
3939 ListBuffer<Type> interfaces = new ListBuffer<>();
3940 Set<Type> toSkip = new HashSet<>();
3941 while (!cl.isEmpty()) {
3942 Type current = cl.head;
3943 boolean keep = !toSkip.contains(current);
3944 if (keep && current.hasTag(TYPEVAR)) {
3945 // skip lower-bounded variables with a subtype in cl.tail
3946 for (Type t : cl.tail) {
3947 if (isSubtypeNoCapture(t, current)) {
3948 keep = false;
3949 break;
3950 }
3951 }
3952 }
3953 if (keep) {
3954 if (current.isInterface())
3955 interfaces.append(current);
3956 else
3957 classes.append(current);
3958 for (Type t : cl.tail) {
3959 // skip supertypes of 'current' in cl.tail
3960 if (isSubtypeNoCapture(current, t))
3961 toSkip.add(t);
3962 }
3963 }
3964 cl = cl.tail;
3965 }
3966 return classes.appendList(interfaces).toList();
3967 }
3968
3969 /**
3970 * Return the least upper bound of list of types. if the lub does
3971 * not exist return null.
3972 */
3973 public Type lub(List<Type> ts) {
3974 return lub(ts.toArray(new Type[ts.length()]));
3975 }
3976
3977 /**
3978 * Return the least upper bound (lub) of set of types. If the lub
3979 * does not exist return the type of null (bottom).
3980 */
3981 public Type lub(Type... ts) {
3982 final int UNKNOWN_BOUND = 0;
3983 final int ARRAY_BOUND = 1;
3984 final int CLASS_BOUND = 2;
3985
3986 int[] kinds = new int[ts.length];
3987
3988 int boundkind = UNKNOWN_BOUND;
3989 for (int i = 0 ; i < ts.length ; i++) {
3990 Type t = ts[i];
3991 switch (t.getTag()) {
3992 case CLASS:
3993 boundkind |= kinds[i] = CLASS_BOUND;
3994 break;
3995 case ARRAY:
3996 boundkind |= kinds[i] = ARRAY_BOUND;
3997 break;
3998 case TYPEVAR:
3999 do {
4000 t = t.getUpperBound();
4001 } while (t.hasTag(TYPEVAR));
4002 if (t.hasTag(ARRAY)) {
4003 boundkind |= kinds[i] = ARRAY_BOUND;
4004 } else {
4005 boundkind |= kinds[i] = CLASS_BOUND;
4006 }
4007 break;
4008 default:
4009 kinds[i] = UNKNOWN_BOUND;
4010 if (t.isPrimitive())
4011 return syms.errType;
4012 }
4013 }
4014 switch (boundkind) {
4015 case 0:
4016 return syms.botType;
4017
4018 case ARRAY_BOUND:
4019 // calculate lub(A[], B[])
4020 Type[] elements = new Type[ts.length];
4021 for (int i = 0 ; i < ts.length ; i++) {
4022 Type elem = elements[i] = elemTypeFun.apply(ts[i]);
4023 if (elem.isPrimitive()) {
4024 // if a primitive type is found, then return
4025 // arraySuperType unless all the types are the
4026 // same
4027 Type first = ts[0];
4028 for (int j = 1 ; j < ts.length ; j++) {
4029 if (!isSameType(first, ts[j])) {
4030 // lub(int[], B[]) is Cloneable & Serializable
4031 return arraySuperType();
4032 }
4033 }
4034 // all the array types are the same, return one
4035 // lub(int[], int[]) is int[]
4036 return first;
4037 }
4038 }
4039 // lub(A[], B[]) is lub(A, B)[]
4040 return new ArrayType(lub(elements), syms.arrayClass);
4041
4042 case CLASS_BOUND:
4043 // calculate lub(A, B)
4044 int startIdx = 0;
4045 for (int i = 0; i < ts.length ; i++) {
4046 Type t = ts[i];
4047 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) {
4048 break;
4049 } else {
4050 startIdx++;
4051 }
4052 }
4053 Assert.check(startIdx < ts.length);
4054 //step 1 - compute erased candidate set (EC)
4055 List<Type> cl = erasedSupertypes(ts[startIdx]);
4056 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4057 Type t = ts[i];
4058 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
4059 cl = intersect(cl, erasedSupertypes(t));
4060 }
4061 //step 2 - compute minimal erased candidate set (MEC)
4062 List<Type> mec = closureMin(cl);
4063 //step 3 - for each element G in MEC, compute lci(Inv(G))
4064 List<Type> candidates = List.nil();
4065 for (Type erasedSupertype : mec) {
4066 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
4067 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4068 Type superType = asSuper(ts[i], erasedSupertype.tsym);
4069 lci = intersect(lci, superType != null ? List.of(superType) : List.nil());
4070 }
4071 candidates = candidates.appendList(lci);
4072 }
4073 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
4074 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
4075 return compoundMin(candidates);
4076
4077 default:
4078 // calculate lub(A, B[])
4079 List<Type> classes = List.of(arraySuperType());
4080 for (int i = 0 ; i < ts.length ; i++) {
4081 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays
4082 classes = classes.prepend(ts[i]);
4083 }
4084 // lub(A, B[]) is lub(A, arraySuperType)
4085 return lub(classes);
4086 }
4087 }
4088 // where
4089 List<Type> erasedSupertypes(Type t) {
4090 ListBuffer<Type> buf = new ListBuffer<>();
4091 for (Type sup : closure(t)) {
4092 if (sup.hasTag(TYPEVAR)) {
4093 buf.append(sup);
4094 } else {
4095 buf.append(erasure(sup));
4096 }
4097 }
4098 return buf.toList();
4099 }
4100
4101 private Type arraySuperType;
4102 private Type arraySuperType() {
4103 // initialized lazily to avoid problems during compiler startup
4104 if (arraySuperType == null) {
4105 // JLS 10.8: all arrays implement Cloneable and Serializable.
4106 arraySuperType = makeIntersectionType(List.of(syms.serializableType,
4107 syms.cloneableType), true);
4108 }
4109 return arraySuperType;
4110 }
4111 // </editor-fold>
4112
4113 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
4114 public Type glb(List<Type> ts) {
4115 Type t1 = ts.head;
4116 for (Type t2 : ts.tail) {
4117 if (t1.isErroneous())
4118 return t1;
4119 t1 = glb(t1, t2);
4120 }
4121 return t1;
4122 }
4123 //where
4124 public Type glb(Type t, Type s) {
4125 if (s == null)
4126 return t;
4127 else if (t.isPrimitive() || s.isPrimitive())
4128 return syms.errType;
4129 else if (isSubtypeNoCapture(t, s))
4130 return t;
4131 else if (isSubtypeNoCapture(s, t))
4132 return s;
4133
4134 List<Type> closure = union(closure(t), closure(s));
4135 return glbFlattened(closure, t);
4136 }
4137 //where
4138 /**
4139 * Perform glb for a list of non-primitive, non-error, non-compound types;
4140 * redundant elements are removed. Bounds should be ordered according to
4141 * {@link Symbol#precedes(TypeSymbol,Types)}.
4142 *
4143 * @param flatBounds List of type to glb
4144 * @param errT Original type to use if the result is an error type
4145 */
4146 private Type glbFlattened(List<Type> flatBounds, Type errT) {
4147 List<Type> bounds = closureMin(flatBounds);
4148
4149 if (bounds.isEmpty()) { // length == 0
4150 return syms.objectType;
4151 } else if (bounds.tail.isEmpty()) { // length == 1
4152 return bounds.head;
4153 } else { // length > 1
4154 int classCount = 0;
4155 List<Type> cvars = List.nil();
4156 List<Type> lowers = List.nil();
4157 for (Type bound : bounds) {
4158 if (!bound.isInterface()) {
4159 classCount++;
4160 Type lower = cvarLowerBound(bound);
4161 if (bound != lower && !lower.hasTag(BOT)) {
4162 cvars = cvars.append(bound);
4163 lowers = lowers.append(lower);
4164 }
4165 }
4166 }
4167 if (classCount > 1) {
4168 if (lowers.isEmpty()) {
4169 return createErrorType(errT);
4170 } else {
4171 // try again with lower bounds included instead of capture variables
4172 List<Type> newBounds = bounds.diff(cvars).appendList(lowers);
4173 return glb(newBounds);
4174 }
4175 }
4176 }
4177 return makeIntersectionType(bounds);
4178 }
4179 // </editor-fold>
4180
4181 // <editor-fold defaultstate="collapsed" desc="hashCode">
4182 /**
4183 * Compute a hash code on a type.
4184 */
4185 public int hashCode(Type t) {
4186 return hashCode(t, false);
4187 }
4188
4189 public int hashCode(Type t, boolean strict) {
4190 return strict ?
4191 hashCodeStrictVisitor.visit(t) :
4192 hashCodeVisitor.visit(t);
4193 }
4194 // where
4195 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor();
4196 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() {
4197 @Override
4198 public Integer visitTypeVar(TypeVar t, Void ignored) {
4199 return System.identityHashCode(t);
4200 }
4201 };
4202
4203 private static class HashCodeVisitor extends UnaryVisitor<Integer> {
4204 public Integer visitType(Type t, Void ignored) {
4205 return t.getTag().ordinal();
4206 }
4207
4208 @Override
4209 public Integer visitClassType(ClassType t, Void ignored) {
4210 int result = visit(t.getEnclosingType());
4211 result *= 127;
4212 result += t.tsym.flatName().hashCode();
4213 for (Type s : t.getTypeArguments()) {
4214 result *= 127;
4215 result += visit(s);
4216 }
4217 return result;
4218 }
4219
4220 @Override
4221 public Integer visitMethodType(MethodType t, Void ignored) {
4222 int h = METHOD.ordinal();
4223 for (List<Type> thisargs = t.argtypes;
4224 thisargs.tail != null;
4225 thisargs = thisargs.tail)
4226 h = (h << 5) + visit(thisargs.head);
4227 return (h << 5) + visit(t.restype);
4228 }
4229
4230 @Override
4231 public Integer visitWildcardType(WildcardType t, Void ignored) {
4232 int result = t.kind.hashCode();
4233 if (t.type != null) {
4234 result *= 127;
4235 result += visit(t.type);
4236 }
4237 return result;
4238 }
4239
4240 @Override
4241 public Integer visitArrayType(ArrayType t, Void ignored) {
4242 return visit(t.elemtype) + 12;
4243 }
4244
4245 @Override
4246 public Integer visitTypeVar(TypeVar t, Void ignored) {
4247 return System.identityHashCode(t);
4248 }
4249
4250 @Override
4251 public Integer visitUndetVar(UndetVar t, Void ignored) {
4252 return System.identityHashCode(t);
4253 }
4254
4255 @Override
4256 public Integer visitErrorType(ErrorType t, Void ignored) {
4257 return 0;
4258 }
4259 }
4260 // </editor-fold>
4261
4262 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
4263 /**
4264 * Does t have a result that is a subtype of the result type of s,
4265 * suitable for covariant returns? It is assumed that both types
4266 * are (possibly polymorphic) method types. Monomorphic method
4267 * types are handled in the obvious way. Polymorphic method types
4268 * require renaming all type variables of one to corresponding
4269 * type variables in the other, where correspondence is by
4270 * position in the type parameter list. */
4271 public boolean resultSubtype(Type t, Type s, Warner warner) {
4272 List<Type> tvars = t.getTypeArguments();
4273 List<Type> svars = s.getTypeArguments();
4274 Type tres = t.getReturnType();
4275 Type sres = subst(s.getReturnType(), svars, tvars);
4276 return covariantReturnType(tres, sres, warner);
4277 }
4278
4279 /**
4280 * Return-Type-Substitutable.
4281 * @jls 8.4.5 Method Result
4282 */
4283 public boolean returnTypeSubstitutable(Type r1, Type r2) {
4284 if (hasSameArgs(r1, r2))
4285 return resultSubtype(r1, r2, noWarnings);
4286 else
4287 return covariantReturnType(r1.getReturnType(),
4288 erasure(r2.getReturnType()),
4289 noWarnings);
4290 }
4291
4292 public boolean returnTypeSubstitutable(Type r1,
4293 Type r2, Type r2res,
4294 Warner warner) {
4295 if (isSameType(r1.getReturnType(), r2res))
4296 return true;
4297 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
4298 return false;
4299
4300 if (hasSameArgs(r1, r2))
4301 return covariantReturnType(r1.getReturnType(), r2res, warner);
4302 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
4303 return true;
4304 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
4305 return false;
4306 warner.warn(LintCategory.UNCHECKED);
4307 return true;
4308 }
4309
4310 /**
4311 * Is t an appropriate return type in an overrider for a
4312 * method that returns s?
4313 */
4314 public boolean covariantReturnType(Type t, Type s, Warner warner) {
4315 return
4316 isSameType(t, s) ||
4317 !t.isPrimitive() &&
4318 !s.isPrimitive() &&
4319 isAssignable(t, s, warner);
4320 }
4321 // </editor-fold>
4322
4323 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
4324 /**
4325 * Return the class that boxes the given primitive.
4326 */
4327 public ClassSymbol boxedClass(Type t) {
4328 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]);
4329 }
4330
4331 /**
4332 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
4333 */
4334 public Type boxedTypeOrType(Type t) {
4335 return t.isPrimitive() ?
4336 boxedClass(t).type :
4337 t;
4338 }
4339
4340 /**
4341 * Return the primitive type corresponding to a boxed type.
4342 */
4343 public Type unboxedType(Type t) {
4344 if (t.hasTag(ERROR))
4345 return Type.noType;
4346 for (int i=0; i<syms.boxedName.length; i++) {
4347 Name box = syms.boxedName[i];
4348 if (box != null &&
4349 asSuper(t, syms.enterClass(syms.java_base, box)) != null)
4350 return syms.typeOfTag[i];
4351 }
4352 return Type.noType;
4353 }
4354
4355 /**
4356 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
4357 */
4358 public Type unboxedTypeOrType(Type t) {
4359 Type unboxedType = unboxedType(t);
4360 return unboxedType.hasTag(NONE) ? t : unboxedType;
4361 }
4362 // </editor-fold>
4363
4364 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
4365 /*
4366 * JLS 5.1.10 Capture Conversion:
4367 *
4368 * Let G name a generic type declaration with n formal type
4369 * parameters A1 ... An with corresponding bounds U1 ... Un. There
4370 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
4371 * where, for 1 <= i <= n:
4372 *
4373 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
4374 * Si is a fresh type variable whose upper bound is
4375 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
4376 * type.
4377 *
4378 * + If Ti is a wildcard type argument of the form ? extends Bi,
4379 * then Si is a fresh type variable whose upper bound is
4380 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
4381 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
4382 * a compile-time error if for any two classes (not interfaces)
4383 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
4384 *
4385 * + If Ti is a wildcard type argument of the form ? super Bi,
4386 * then Si is a fresh type variable whose upper bound is
4387 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
4388 *
4389 * + Otherwise, Si = Ti.
4390 *
4391 * Capture conversion on any type other than a parameterized type
4392 * (4.5) acts as an identity conversion (5.1.1). Capture
4393 * conversions never require a special action at run time and
4394 * therefore never throw an exception at run time.
4395 *
4396 * Capture conversion is not applied recursively.
4397 */
4398 /**
4399 * Capture conversion as specified by the JLS.
4400 */
4401
4402 public List<Type> capture(List<Type> ts) {
4403 List<Type> buf = List.nil();
4404 for (Type t : ts) {
4405 buf = buf.prepend(capture(t));
4406 }
4407 return buf.reverse();
4408 }
4409
4410 public Type capture(Type t) {
4411 if (!t.hasTag(CLASS)) {
4412 return t;
4413 }
4414 if (t.getEnclosingType() != Type.noType) {
4415 Type capturedEncl = capture(t.getEnclosingType());
4416 if (capturedEncl != t.getEnclosingType()) {
4417 Type type1 = memberType(capturedEncl, t.tsym);
4418 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
4419 }
4420 }
4421 ClassType cls = (ClassType)t;
4422 if (cls.isRaw() || !cls.isParameterized())
4423 return cls;
4424
4425 ClassType G = (ClassType)cls.asElement().asType();
4426 List<Type> A = G.getTypeArguments();
4427 List<Type> T = cls.getTypeArguments();
4428 List<Type> S = freshTypeVariables(T);
4429
4430 List<Type> currentA = A;
4431 List<Type> currentT = T;
4432 List<Type> currentS = S;
4433 boolean captured = false;
4434 while (!currentA.isEmpty() &&
4435 !currentT.isEmpty() &&
4436 !currentS.isEmpty()) {
4437 if (currentS.head != currentT.head) {
4438 captured = true;
4439 WildcardType Ti = (WildcardType)currentT.head;
4440 Type Ui = currentA.head.getUpperBound();
4441 CapturedType Si = (CapturedType)currentS.head;
4442 if (Ui == null)
4443 Ui = syms.objectType;
4444 switch (Ti.kind) {
4445 case UNBOUND:
4446 Si.setUpperBound( subst(Ui, A, S) );
4447 Si.lower = syms.botType;
4448 break;
4449 case EXTENDS:
4450 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) );
4451 Si.lower = syms.botType;
4452 break;
4453 case SUPER:
4454 Si.setUpperBound( subst(Ui, A, S) );
4455 Si.lower = Ti.getSuperBound();
4456 break;
4457 }
4458 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound();
4459 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower;
4460 if (!Si.getUpperBound().hasTag(ERROR) &&
4461 !Si.lower.hasTag(ERROR) &&
4462 isSameType(tmpBound, tmpLower)) {
4463 currentS.head = Si.getUpperBound();
4464 }
4465 }
4466 currentA = currentA.tail;
4467 currentT = currentT.tail;
4468 currentS = currentS.tail;
4469 }
4470 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
4471 return erasure(t); // some "rare" type involved
4472
4473 if (captured)
4474 return new ClassType(cls.getEnclosingType(), S, cls.tsym,
4475 cls.getMetadata());
4476 else
4477 return t;
4478 }
4479 // where
4480 public List<Type> freshTypeVariables(List<Type> types) {
4481 ListBuffer<Type> result = new ListBuffer<>();
4482 for (Type t : types) {
4483 if (t.hasTag(WILDCARD)) {
4484 Type bound = ((WildcardType)t).getExtendsBound();
4485 if (bound == null)
4486 bound = syms.objectType;
4487 result.append(new CapturedType(capturedName,
4488 syms.noSymbol,
4489 bound,
4490 syms.botType,
4491 (WildcardType)t));
4492 } else {
4493 result.append(t);
4494 }
4495 }
4496 return result.toList();
4497 }
4498 // </editor-fold>
4499
4500 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
4501 private boolean sideCast(Type from, Type to, Warner warn) {
4502 // We are casting from type $from$ to type $to$, which are
4503 // non-final unrelated types. This method
4504 // tries to reject a cast by transferring type parameters
4505 // from $to$ to $from$ by common superinterfaces.
4506 boolean reverse = false;
4507 Type target = to;
4508 if ((to.tsym.flags() & INTERFACE) == 0) {
4509 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4510 reverse = true;
4511 to = from;
4512 from = target;
4513 }
4514 List<Type> commonSupers = superClosure(to, erasure(from));
4515 boolean giveWarning = commonSupers.isEmpty();
4516 // The arguments to the supers could be unified here to
4517 // get a more accurate analysis
4518 while (commonSupers.nonEmpty()) {
4519 Type t1 = asSuper(from, commonSupers.head.tsym);
4520 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
4521 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4522 return false;
4523 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
4524 commonSupers = commonSupers.tail;
4525 }
4526 if (giveWarning && !isReifiable(reverse ? from : to))
4527 warn.warn(LintCategory.UNCHECKED);
4528 return true;
4529 }
4530
4531 private boolean sideCastFinal(Type from, Type to, Warner warn) {
4532 // We are casting from type $from$ to type $to$, which are
4533 // unrelated types one of which is final and the other of
4534 // which is an interface. This method
4535 // tries to reject a cast by transferring type parameters
4536 // from the final class to the interface.
4537 boolean reverse = false;
4538 Type target = to;
4539 if ((to.tsym.flags() & INTERFACE) == 0) {
4540 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4541 reverse = true;
4542 to = from;
4543 from = target;
4544 }
4545 Assert.check((from.tsym.flags() & FINAL) != 0);
4546 Type t1 = asSuper(from, to.tsym);
4547 if (t1 == null) return false;
4548 Type t2 = to;
4549 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4550 return false;
4551 if (!isReifiable(target) &&
4552 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
4553 warn.warn(LintCategory.UNCHECKED);
4554 return true;
4555 }
4556
4557 private boolean giveWarning(Type from, Type to) {
4558 List<Type> bounds = to.isCompound() ?
4559 directSupertypes(to) : List.of(to);
4560 for (Type b : bounds) {
4561 Type subFrom = asSub(from, b.tsym);
4562 if (b.isParameterized() &&
4563 (!(isUnbounded(b) ||
4564 isSubtype(from, b) ||
4565 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
4566 return true;
4567 }
4568 }
4569 return false;
4570 }
4571
4572 private List<Type> superClosure(Type t, Type s) {
4573 List<Type> cl = List.nil();
4574 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
4575 if (isSubtype(s, erasure(l.head))) {
4576 cl = insert(cl, l.head);
4577 } else {
4578 cl = union(cl, superClosure(l.head, s));
4579 }
4580 }
4581 return cl;
4582 }
4583
4584 private boolean containsTypeEquivalent(Type t, Type s) {
4585 return isSameType(t, s) || // shortcut
4586 containsType(t, s) && containsType(s, t);
4587 }
4588
4589 // <editor-fold defaultstate="collapsed" desc="adapt">
4590 /**
4591 * Adapt a type by computing a substitution which maps a source
4592 * type to a target type.
4593 *
4594 * @param source the source type
4595 * @param target the target type
4596 * @param from the type variables of the computed substitution
4597 * @param to the types of the computed substitution.
4598 */
4599 public void adapt(Type source,
4600 Type target,
4601 ListBuffer<Type> from,
4602 ListBuffer<Type> to) throws AdaptFailure {
4603 new Adapter(from, to).adapt(source, target);
4604 }
4605
4606 class Adapter extends SimpleVisitor<Void, Type> {
4607
4608 ListBuffer<Type> from;
4609 ListBuffer<Type> to;
4610 Map<Symbol,Type> mapping;
4611
4612 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
4613 this.from = from;
4614 this.to = to;
4615 mapping = new HashMap<>();
4616 }
4617
4618 public void adapt(Type source, Type target) throws AdaptFailure {
4619 visit(source, target);
4620 List<Type> fromList = from.toList();
4621 List<Type> toList = to.toList();
4622 while (!fromList.isEmpty()) {
4623 Type val = mapping.get(fromList.head.tsym);
4624 if (toList.head != val)
4625 toList.head = val;
4626 fromList = fromList.tail;
4627 toList = toList.tail;
4628 }
4629 }
4630
4631 @Override
4632 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
4633 if (target.hasTag(CLASS))
4634 adaptRecursive(source.allparams(), target.allparams());
4635 return null;
4636 }
4637
4638 @Override
4639 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
4640 if (target.hasTag(ARRAY))
4641 adaptRecursive(elemtype(source), elemtype(target));
4642 return null;
4643 }
4644
4645 @Override
4646 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
4647 if (source.isExtendsBound())
4648 adaptRecursive(wildUpperBound(source), wildUpperBound(target));
4649 else if (source.isSuperBound())
4650 adaptRecursive(wildLowerBound(source), wildLowerBound(target));
4651 return null;
4652 }
4653
4654 @Override
4655 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
4656 // Check to see if there is
4657 // already a mapping for $source$, in which case
4658 // the old mapping will be merged with the new
4659 Type val = mapping.get(source.tsym);
4660 if (val != null) {
4661 if (val.isSuperBound() && target.isSuperBound()) {
4662 val = isSubtype(wildLowerBound(val), wildLowerBound(target))
4663 ? target : val;
4664 } else if (val.isExtendsBound() && target.isExtendsBound()) {
4665 val = isSubtype(wildUpperBound(val), wildUpperBound(target))
4666 ? val : target;
4667 } else if (!isSameType(val, target)) {
4668 throw new AdaptFailure();
4669 }
4670 } else {
4671 val = target;
4672 from.append(source);
4673 to.append(target);
4674 }
4675 mapping.put(source.tsym, val);
4676 return null;
4677 }
4678
4679 @Override
4680 public Void visitType(Type source, Type target) {
4681 return null;
4682 }
4683
4684 private Set<TypePair> cache = new HashSet<>();
4685
4686 private void adaptRecursive(Type source, Type target) {
4687 TypePair pair = new TypePair(source, target);
4688 if (cache.add(pair)) {
4689 try {
4690 visit(source, target);
4691 } finally {
4692 cache.remove(pair);
4693 }
4694 }
4695 }
4696
4697 private void adaptRecursive(List<Type> source, List<Type> target) {
4698 if (source.length() == target.length()) {
4699 while (source.nonEmpty()) {
4700 adaptRecursive(source.head, target.head);
4701 source = source.tail;
4702 target = target.tail;
4703 }
4704 }
4705 }
4706 }
4707
4708 public static class AdaptFailure extends RuntimeException {
4709 static final long serialVersionUID = -7490231548272701566L;
4710 }
4711
4712 private void adaptSelf(Type t,
4713 ListBuffer<Type> from,
4714 ListBuffer<Type> to) {
4715 try {
4716 //if (t.tsym.type != t)
4717 adapt(t.tsym.type, t, from, to);
4718 } catch (AdaptFailure ex) {
4719 // Adapt should never fail calculating a mapping from
4720 // t.tsym.type to t as there can be no merge problem.
4721 throw new AssertionError(ex);
4722 }
4723 }
4724 // </editor-fold>
4725
4726 /**
4727 * Rewrite all type variables (universal quantifiers) in the given
4728 * type to wildcards (existential quantifiers). This is used to
4729 * determine if a cast is allowed. For example, if high is true
4730 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4731 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4732 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4733 * List<Integer>} with a warning.
4734 * @param t a type
4735 * @param high if true return an upper bound; otherwise a lower
4736 * bound
4737 * @param rewriteTypeVars only rewrite captured wildcards if false;
4738 * otherwise rewrite all type variables
4739 * @return the type rewritten with wildcards (existential
4740 * quantifiers) only
4741 */
4742 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4743 return new Rewriter(high, rewriteTypeVars).visit(t);
4744 }
4745
4746 class Rewriter extends UnaryVisitor<Type> {
4747
4748 boolean high;
4749 boolean rewriteTypeVars;
4750
4751 Rewriter(boolean high, boolean rewriteTypeVars) {
4752 this.high = high;
4753 this.rewriteTypeVars = rewriteTypeVars;
4754 }
4755
4756 @Override
4757 public Type visitClassType(ClassType t, Void s) {
4758 ListBuffer<Type> rewritten = new ListBuffer<>();
4759 boolean changed = false;
4760 for (Type arg : t.allparams()) {
4761 Type bound = visit(arg);
4762 if (arg != bound) {
4763 changed = true;
4764 }
4765 rewritten.append(bound);
4766 }
4767 if (changed)
4768 return subst(t.tsym.type,
4769 t.tsym.type.allparams(),
4770 rewritten.toList());
4771 else
4772 return t;
4773 }
4774
4775 public Type visitType(Type t, Void s) {
4776 return t;
4777 }
4778
4779 @Override
4780 public Type visitCapturedType(CapturedType t, Void s) {
4781 Type w_bound = t.wildcard.type;
4782 Type bound = w_bound.contains(t) ?
4783 erasure(w_bound) :
4784 visit(w_bound);
4785 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4786 }
4787
4788 @Override
4789 public Type visitTypeVar(TypeVar t, Void s) {
4790 if (rewriteTypeVars) {
4791 Type bound = t.getUpperBound().contains(t) ?
4792 erasure(t.getUpperBound()) :
4793 visit(t.getUpperBound());
4794 return rewriteAsWildcardType(bound, t, EXTENDS);
4795 } else {
4796 return t;
4797 }
4798 }
4799
4800 @Override
4801 public Type visitWildcardType(WildcardType t, Void s) {
4802 Type bound2 = visit(t.type);
4803 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4804 }
4805
4806 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4807 switch (bk) {
4808 case EXTENDS: return high ?
4809 makeExtendsWildcard(B(bound), formal) :
4810 makeExtendsWildcard(syms.objectType, formal);
4811 case SUPER: return high ?
4812 makeSuperWildcard(syms.botType, formal) :
4813 makeSuperWildcard(B(bound), formal);
4814 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4815 default:
4816 Assert.error("Invalid bound kind " + bk);
4817 return null;
4818 }
4819 }
4820
4821 Type B(Type t) {
4822 while (t.hasTag(WILDCARD)) {
4823 WildcardType w = (WildcardType)t;
4824 t = high ?
4825 w.getExtendsBound() :
4826 w.getSuperBound();
4827 if (t == null) {
4828 t = high ? syms.objectType : syms.botType;
4829 }
4830 }
4831 return t;
4832 }
4833 }
4834
4835
4836 /**
4837 * Create a wildcard with the given upper (extends) bound; create
4838 * an unbounded wildcard if bound is Object.
4839 *
4840 * @param bound the upper bound
4841 * @param formal the formal type parameter that will be
4842 * substituted by the wildcard
4843 */
4844 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4845 if (bound == syms.objectType) {
4846 return new WildcardType(syms.objectType,
4847 BoundKind.UNBOUND,
4848 syms.boundClass,
4849 formal);
4850 } else {
4851 return new WildcardType(bound,
4852 BoundKind.EXTENDS,
4853 syms.boundClass,
4854 formal);
4855 }
4856 }
4857
4858 /**
4859 * Create a wildcard with the given lower (super) bound; create an
4860 * unbounded wildcard if bound is bottom (type of {@code null}).
4861 *
4862 * @param bound the lower bound
4863 * @param formal the formal type parameter that will be
4864 * substituted by the wildcard
4865 */
4866 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4867 if (bound.hasTag(BOT)) {
4868 return new WildcardType(syms.objectType,
4869 BoundKind.UNBOUND,
4870 syms.boundClass,
4871 formal);
4872 } else {
4873 return new WildcardType(bound,
4874 BoundKind.SUPER,
4875 syms.boundClass,
4876 formal);
4877 }
4878 }
4879
4880 /**
4881 * A wrapper for a type that allows use in sets.
4882 */
4883 public static class UniqueType {
4884 public final Type type;
4885 final Types types;
4886 private boolean encodeTypeSig;
4887
4888 public UniqueType(Type type, Types types, boolean encodeTypeSig) {
4889 this.type = type;
4890 this.types = types;
4891 this.encodeTypeSig = encodeTypeSig;
4892 }
4893
4894 public UniqueType(Type type, Types types) {
4895 this(type, types, true);
4896 }
4897
4898 public int hashCode() {
4899 return types.hashCode(type);
4900 }
4901
4902 public boolean equals(Object obj) {
4903 return (obj instanceof UniqueType uniqueType) &&
4904 types.isSameType(type, uniqueType.type);
4905 }
4906
4907 public boolean encodeTypeSig() {
4908 return encodeTypeSig;
4909 }
4910
4911 public String toString() {
4912 return type.toString();
4913 }
4914
4915 }
4916 // </editor-fold>
4917
4918 // <editor-fold defaultstate="collapsed" desc="Visitors">
4919 /**
4920 * A default visitor for types. All visitor methods except
4921 * visitType are implemented by delegating to visitType. Concrete
4922 * subclasses must provide an implementation of visitType and can
4923 * override other methods as needed.
4924 *
4925 * @param <R> the return type of the operation implemented by this
4926 * visitor; use Void if no return type is needed.
4927 * @param <S> the type of the second argument (the first being the
4928 * type itself) of the operation implemented by this visitor; use
4929 * Void if a second argument is not needed.
4930 */
4931 public abstract static class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4932 public final R visit(Type t, S s) { return t.accept(this, s); }
4933 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4934 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4935 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4936 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4937 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4938 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); }
4939 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4940 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4941 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4942 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4943 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4944 }
4945
4946 /**
4947 * A default visitor for symbols. All visitor methods except
4948 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4949 * subclasses must provide an implementation of visitSymbol and can
4950 * override other methods as needed.
4951 *
4952 * @param <R> the return type of the operation implemented by this
4953 * visitor; use Void if no return type is needed.
4954 * @param <S> the type of the second argument (the first being the
4955 * symbol itself) of the operation implemented by this visitor; use
4956 * Void if a second argument is not needed.
4957 */
4958 public abstract static class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4959 public final R visit(Symbol s, S arg) { return s.accept(this, arg); }
4960 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4961 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4962 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4963 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4964 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4965 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4966 }
4967
4968 /**
4969 * A <em>simple</em> visitor for types. This visitor is simple as
4970 * captured wildcards, for-all types (generic methods), and
4971 * undetermined type variables (part of inference) are hidden.
4972 * Captured wildcards are hidden by treating them as type
4973 * variables and the rest are hidden by visiting their qtypes.
4974 *
4975 * @param <R> the return type of the operation implemented by this
4976 * visitor; use Void if no return type is needed.
4977 * @param <S> the type of the second argument (the first being the
4978 * type itself) of the operation implemented by this visitor; use
4979 * Void if a second argument is not needed.
4980 */
4981 public abstract static class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4982 @Override
4983 public R visitCapturedType(CapturedType t, S s) {
4984 return visitTypeVar(t, s);
4985 }
4986 @Override
4987 public R visitForAll(ForAll t, S s) {
4988 return visit(t.qtype, s);
4989 }
4990 @Override
4991 public R visitUndetVar(UndetVar t, S s) {
4992 return visit(t.qtype, s);
4993 }
4994 }
4995
4996 /**
4997 * A plain relation on types. That is a 2-ary function on the
4998 * form Type × Type → Boolean.
4999 * <!-- In plain text: Type x Type -> Boolean -->
5000 */
5001 public abstract static class TypeRelation extends SimpleVisitor<Boolean,Type> {}
5002
5003 /**
5004 * A convenience visitor for implementing operations that only
5005 * require one argument (the type itself), that is, unary
5006 * operations.
5007 *
5008 * @param <R> the return type of the operation implemented by this
5009 * visitor; use Void if no return type is needed.
5010 */
5011 public abstract static class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
5012 public final R visit(Type t) { return t.accept(this, null); }
5013 }
5014
5015 /**
5016 * A visitor for implementing a mapping from types to types. The
5017 * default behavior of this class is to implement the identity
5018 * mapping (mapping a type to itself). This can be overridden in
5019 * subclasses.
5020 *
5021 * @param <S> the type of the second argument (the first being the
5022 * type itself) of this mapping; use Void if a second argument is
5023 * not needed.
5024 */
5025 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
5026 public final Type visit(Type t) { return t.accept(this, null); }
5027 public Type visitType(Type t, S s) { return t; }
5028 }
5029
5030 /**
5031 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}.
5032 * This class implements the functional interface {@code Function}, that allows it to be used
5033 * fluently in stream-like processing.
5034 */
5035 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> {
5036 @Override
5037 public Type apply(Type type) { return visit(type); }
5038
5039 List<Type> visit(List<Type> ts, S s) {
5040 return ts.map(t -> visit(t, s));
5041 }
5042
5043 @Override
5044 public Type visitCapturedType(CapturedType t, S s) {
5045 return visitTypeVar(t, s);
5046 }
5047 }
5048 // </editor-fold>
5049
5050 // <editor-fold defaultstate="collapsed" desc="Unconditionality">
5051 /** Check unconditionality between any combination of reference or primitive types.
5052 *
5053 * Rules:
5054 * an identity conversion
5055 * a widening reference conversion
5056 * a widening primitive conversion (delegates to `checkUnconditionallyExactPrimitives`)
5057 * a boxing conversion
5058 * a boxing conversion followed by a widening reference conversion
5059 *
5060 * @param source Source primitive or reference type
5061 * @param target Target primitive or reference type
5062 */
5063 public boolean isUnconditionallyExact(Type source, Type target) {
5064 if (isSameType(source, target)) {
5065 return true;
5066 }
5067
5068 return target.isPrimitive()
5069 ? isUnconditionallyExactPrimitives(source, target)
5070 : isSubtype(boxedTypeOrType(erasure(source)), target);
5071 }
5072
5073 /** Check unconditionality between primitive types.
5074 *
5075 * - widening from one integral type to another,
5076 * - widening from one floating point type to another,
5077 * - widening from byte, short, or char to a floating point type,
5078 * - widening from int to double.
5079 *
5080 * @param selectorType Type of selector
5081 * @param targetType Target type
5082 */
5083 public boolean isUnconditionallyExactPrimitives(Type selectorType, Type targetType) {
5084 if (isSameType(selectorType, targetType)) {
5085 return true;
5086 }
5087
5088 return (selectorType.isPrimitive() && targetType.isPrimitive()) &&
5089 ((selectorType.hasTag(BYTE) && !targetType.hasTag(CHAR)) ||
5090 (selectorType.hasTag(SHORT) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag()))) ||
5091 (selectorType.hasTag(CHAR) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag()))) ||
5092 (selectorType.hasTag(INT) && (targetType.hasTag(DOUBLE) || targetType.hasTag(LONG))) ||
5093 (selectorType.hasTag(FLOAT) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag()))));
5094 }
5095 // </editor-fold>
5096
5097 // <editor-fold defaultstate="collapsed" desc="Annotation support">
5098
5099 public RetentionPolicy getRetention(Attribute.Compound a) {
5100 return getRetention(a.type.tsym);
5101 }
5102
5103 public RetentionPolicy getRetention(TypeSymbol sym) {
5104 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
5105 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
5106 if (c != null) {
5107 Attribute value = c.member(names.value);
5108 if (value != null && value instanceof Attribute.Enum attributeEnum) {
5109 Name levelName = attributeEnum.value.name;
5110 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
5111 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
5112 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
5113 else ;// /* fail soft */ throw new AssertionError(levelName);
5114 }
5115 }
5116 return vis;
5117 }
5118 // </editor-fold>
5119
5120 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
5121
5122 public abstract static class SignatureGenerator {
5123
5124 public static class InvalidSignatureException extends RuntimeException {
5125 private static final long serialVersionUID = 0;
5126
5127 private final transient Type type;
5128
5129 InvalidSignatureException(Type type) {
5130 this.type = type;
5131 }
5132
5133 public Type type() {
5134 return type;
5135 }
5136
5137 @Override
5138 public Throwable fillInStackTrace() {
5139 // This is an internal exception; the stack trace is irrelevant.
5140 return this;
5141 }
5142 }
5143
5144 private final Types types;
5145
5146 protected abstract void append(char ch);
5147 protected abstract void append(byte[] ba);
5148 protected abstract void append(Name name);
5149 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
5150
5151 protected SignatureGenerator(Types types) {
5152 this.types = types;
5153 }
5154
5155 protected void reportIllegalSignature(Type t) {
5156 throw new InvalidSignatureException(t);
5157 }
5158
5159 /**
5160 * Assemble signature of given type in string buffer.
5161 */
5162 public void assembleSig(Type type) {
5163 switch (type.getTag()) {
5164 case BYTE:
5165 append('B');
5166 break;
5167 case SHORT:
5168 append('S');
5169 break;
5170 case CHAR:
5171 append('C');
5172 break;
5173 case INT:
5174 append('I');
5175 break;
5176 case LONG:
5177 append('J');
5178 break;
5179 case FLOAT:
5180 append('F');
5181 break;
5182 case DOUBLE:
5183 append('D');
5184 break;
5185 case BOOLEAN:
5186 append('Z');
5187 break;
5188 case VOID:
5189 append('V');
5190 break;
5191 case CLASS:
5192 if (type.isCompound()) {
5193 reportIllegalSignature(type);
5194 }
5195 append('L');
5196 assembleClassSig(type);
5197 append(';');
5198 break;
5199 case ARRAY:
5200 ArrayType at = (ArrayType) type;
5201 append('[');
5202 assembleSig(at.elemtype);
5203 break;
5204 case METHOD:
5205 MethodType mt = (MethodType) type;
5206 append('(');
5207 assembleSig(mt.argtypes);
5208 append(')');
5209 assembleSig(mt.restype);
5210 if (hasTypeVar(mt.thrown)) {
5211 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
5212 append('^');
5213 assembleSig(l.head);
5214 }
5215 }
5216 break;
5217 case WILDCARD: {
5218 Type.WildcardType ta = (Type.WildcardType) type;
5219 switch (ta.kind) {
5220 case SUPER:
5221 append('-');
5222 assembleSig(ta.type);
5223 break;
5224 case EXTENDS:
5225 append('+');
5226 assembleSig(ta.type);
5227 break;
5228 case UNBOUND:
5229 append('*');
5230 break;
5231 default:
5232 throw new AssertionError(ta.kind);
5233 }
5234 break;
5235 }
5236 case TYPEVAR:
5237 if (((TypeVar)type).isCaptured()) {
5238 reportIllegalSignature(type);
5239 }
5240 append('T');
5241 append(type.tsym.name);
5242 append(';');
5243 break;
5244 case FORALL:
5245 Type.ForAll ft = (Type.ForAll) type;
5246 assembleParamsSig(ft.tvars);
5247 assembleSig(ft.qtype);
5248 break;
5249 default:
5250 throw new AssertionError("typeSig " + type.getTag());
5251 }
5252 }
5253
5254 public boolean hasTypeVar(List<Type> l) {
5255 while (l.nonEmpty()) {
5256 if (l.head.hasTag(TypeTag.TYPEVAR)) {
5257 return true;
5258 }
5259 l = l.tail;
5260 }
5261 return false;
5262 }
5263
5264 public void assembleClassSig(Type type) {
5265 ClassType ct = (ClassType) type;
5266 ClassSymbol c = (ClassSymbol) ct.tsym;
5267 classReference(c);
5268 Type outer = ct.getEnclosingType();
5269 if (outer.allparams().nonEmpty()) {
5270 boolean rawOuter =
5271 c.owner.kind == MTH || // either a local class
5272 c.name == types.names.empty; // or anonymous
5273 assembleClassSig(rawOuter
5274 ? types.erasure(outer)
5275 : outer);
5276 append(rawOuter ? '$' : '.');
5277 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
5278 append(rawOuter
5279 ? c.flatname.subName(c.owner.enclClass().flatname.length() + 1)
5280 : c.name);
5281 } else {
5282 append(externalize(c.flatname));
5283 }
5284 if (ct.getTypeArguments().nonEmpty()) {
5285 append('<');
5286 assembleSig(ct.getTypeArguments());
5287 append('>');
5288 }
5289 }
5290
5291 public void assembleParamsSig(List<Type> typarams) {
5292 append('<');
5293 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
5294 Type.TypeVar tvar = (Type.TypeVar) ts.head;
5295 append(tvar.tsym.name);
5296 List<Type> bounds = types.getBounds(tvar);
5297 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
5298 append(':');
5299 }
5300 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
5301 append(':');
5302 assembleSig(l.head);
5303 }
5304 }
5305 append('>');
5306 }
5307
5308 public void assembleSig(List<Type> types) {
5309 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
5310 assembleSig(ts.head);
5311 }
5312 }
5313 }
5314
5315 public Type constantType(LoadableConstant c) {
5316 switch (c.poolTag()) {
5317 case ClassFile.CONSTANT_Class:
5318 return syms.classType;
5319 case ClassFile.CONSTANT_String:
5320 return syms.stringType;
5321 case ClassFile.CONSTANT_Integer:
5322 return syms.intType;
5323 case ClassFile.CONSTANT_Float:
5324 return syms.floatType;
5325 case ClassFile.CONSTANT_Long:
5326 return syms.longType;
5327 case ClassFile.CONSTANT_Double:
5328 return syms.doubleType;
5329 case ClassFile.CONSTANT_MethodHandle:
5330 return syms.methodHandleType;
5331 case ClassFile.CONSTANT_MethodType:
5332 return syms.methodTypeType;
5333 case ClassFile.CONSTANT_Dynamic:
5334 return ((DynamicVarSymbol)c).type;
5335 default:
5336 throw new AssertionError("Not a loadable constant: " + c.poolTag());
5337 }
5338 }
5339 // </editor-fold>
5340
5341 public void newRound() {
5342 descCache._map.clear();
5343 isDerivedRawCache.clear();
5344 implCache._map.clear();
5345 membersCache._map.clear();
5346 closureCache.clear();
5347 }
5348 }