1 /*
2 * Copyright (c) 2003, 2024, 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 static com.sun.tools.javac.main.Option.DOE;
66
67 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
68
69 /**
70 * Utility class containing various operations on types.
71 *
72 * <p>Unless other names are more illustrative, the following naming
73 * conventions should be observed in this file:
74 *
75 * <dl>
76 * <dt>t</dt>
77 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
78 * <dt>s</dt>
79 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
80 * <dt>ts</dt>
81 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
82 * <dt>ss</dt>
83 * <dd>A second list of types should be named ss.</dd>
84 * </dl>
85 *
86 * <p><b>This is NOT part of any supported API.
87 * If you write code that depends on this, you do so at your own risk.
88 * This code and its internal interfaces are subject to change or
89 * deletion without notice.</b>
90 */
91 public class Types {
92 protected static final Context.Key<Types> typesKey = new Context.Key<>();
93
94 final Symtab syms;
95 final JavacMessages messages;
96 final Names names;
97 final Check chk;
98 final Enter enter;
99 JCDiagnostic.Factory diags;
100 List<Warner> warnStack = List.nil();
101 final Name capturedName;
102
103 public final Warner noWarnings;
104 public final boolean dumpStacktraceOnError;
105
106 // <editor-fold defaultstate="collapsed" desc="Instantiating">
107 public static Types instance(Context context) {
108 Types instance = context.get(typesKey);
109 if (instance == null)
110 instance = new Types(context);
111 return instance;
112 }
113
114 @SuppressWarnings("this-escape")
115 protected Types(Context context) {
116 context.put(typesKey, this);
117 syms = Symtab.instance(context);
118 names = Names.instance(context);
119 Source source = Source.instance(context);
120 chk = Check.instance(context);
121 enter = Enter.instance(context);
122 capturedName = names.fromString("<captured wildcard>");
123 messages = JavacMessages.instance(context);
124 diags = JCDiagnostic.Factory.instance(context);
125 noWarnings = new Warner(null) {
126 @Override
127 public String toString() {
128 return "NO_WARNINGS";
129 }
130 };
131 Options options = Options.instance(context);
132 dumpStacktraceOnError = options.isSet("dev") || options.isSet(DOE);
133 }
134 // </editor-fold>
135
136 // <editor-fold defaultstate="collapsed" desc="bounds">
137 /**
138 * Get a wildcard's upper bound, returning non-wildcards unchanged.
139 * @param t a type argument, either a wildcard or a type
140 */
141 public Type wildUpperBound(Type t) {
142 if (t.hasTag(WILDCARD)) {
143 WildcardType w = (WildcardType) t;
144 if (w.isSuperBound())
145 return w.bound == null ? syms.objectType : w.bound.getUpperBound();
146 else
147 return wildUpperBound(w.type);
148 }
149 else return t;
150 }
151
152 /**
153 * Get a capture variable's upper bound, returning other types unchanged.
154 * @param t a type
155 */
156 public Type cvarUpperBound(Type t) {
157 if (t.hasTag(TYPEVAR)) {
158 TypeVar v = (TypeVar) t;
159 return v.isCaptured() ? cvarUpperBound(v.getUpperBound()) : v;
160 }
161 else return t;
162 }
163
164 /**
165 * Get a wildcard's lower bound, returning non-wildcards unchanged.
166 * @param t a type argument, either a wildcard or a type
167 */
168 public Type wildLowerBound(Type t) {
169 if (t.hasTag(WILDCARD)) {
170 WildcardType w = (WildcardType) t;
171 return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type);
172 }
173 else return t;
174 }
175
176 /**
177 * Get a capture variable's lower bound, returning other types unchanged.
178 * @param t a type
179 */
180 public Type cvarLowerBound(Type t) {
181 if (t.hasTag(TYPEVAR) && ((TypeVar) t).isCaptured()) {
182 return cvarLowerBound(t.getLowerBound());
183 }
184 else return t;
185 }
186
187 /**
188 * Recursively skip type-variables until a class/array type is found; capture conversion is then
189 * (optionally) applied to the resulting type. This is useful for i.e. computing a site that is
190 * suitable for a method lookup.
191 */
192 public Type skipTypeVars(Type site, boolean capture) {
193 while (site.hasTag(TYPEVAR)) {
194 site = site.getUpperBound();
195 }
196 return capture ? capture(site) : site;
197 }
198 // </editor-fold>
199
200 // <editor-fold defaultstate="collapsed" desc="projections">
201
202 /**
203 * A projection kind. See {@link TypeProjection}
204 */
205 enum ProjectionKind {
206 UPWARDS() {
207 @Override
208 ProjectionKind complement() {
209 return DOWNWARDS;
210 }
211 },
212 DOWNWARDS() {
213 @Override
214 ProjectionKind complement() {
215 return UPWARDS;
216 }
217 };
218
219 abstract ProjectionKind complement();
220 }
221
222 /**
223 * This visitor performs upwards and downwards projections on types.
224 *
225 * A projection is defined as a function that takes a type T, a set of type variables V and that
226 * produces another type S.
227 *
228 * An upwards projection maps a type T into a type S such that (i) T has no variables in V,
229 * and (ii) S is an upper bound of T.
230 *
231 * A downwards projection maps a type T into a type S such that (i) T has no variables in V,
232 * and (ii) S is a lower bound of T.
233 *
234 * Note that projections are only allowed to touch variables in V. Therefore, it is possible for
235 * a projection to leave its input type unchanged if it does not contain any variables in V.
236 *
237 * Moreover, note that while an upwards projection is always defined (every type as an upper bound),
238 * a downwards projection is not always defined.
239 *
240 * Examples:
241 *
242 * {@code upwards(List<#CAP1>, [#CAP1]) = List<? extends String>, where #CAP1 <: String }
243 * {@code downwards(List<#CAP2>, [#CAP2]) = List<? super String>, where #CAP2 :> String }
244 * {@code upwards(List<#CAP1>, [#CAP2]) = List<#CAP1> }
245 * {@code downwards(List<#CAP1>, [#CAP1]) = not defined }
246 */
247 class TypeProjection extends TypeMapping<ProjectionKind> {
248
249 List<Type> vars;
250 Set<Type> seen = new HashSet<>();
251
252 public TypeProjection(List<Type> vars) {
253 this.vars = vars;
254 }
255
256 @Override
257 public Type visitClassType(ClassType t, ProjectionKind pkind) {
258 if (t.isCompound()) {
259 List<Type> components = directSupertypes(t);
260 List<Type> components1 = components.map(c -> c.map(this, pkind));
261 if (components == components1) return t;
262 else return makeIntersectionType(components1);
263 } else {
264 Type outer = t.getEnclosingType();
265 Type outer1 = visit(outer, pkind);
266 List<Type> typarams = t.getTypeArguments();
267 List<Type> formals = t.tsym.type.getTypeArguments();
268 ListBuffer<Type> typarams1 = new ListBuffer<>();
269 boolean changed = false;
270 for (Type actual : typarams) {
271 Type t2 = mapTypeArgument(t, formals.head.getUpperBound(), actual, pkind);
272 if (t2.hasTag(BOT)) {
273 //not defined
274 return syms.botType;
275 }
276 typarams1.add(t2);
277 changed |= actual != t2;
278 formals = formals.tail;
279 }
280 if (outer1 == outer && !changed) return t;
281 else return new ClassType(outer1, typarams1.toList(), t.tsym, t.getMetadata()) {
282 @Override
283 protected boolean needsStripping() {
284 return true;
285 }
286 };
287 }
288 }
289
290 @Override
291 public Type visitArrayType(ArrayType t, ProjectionKind s) {
292 Type elemtype = t.elemtype;
293 Type elemtype1 = visit(elemtype, s);
294 if (elemtype1 == elemtype) {
295 return t;
296 } else if (elemtype1.hasTag(BOT)) {
297 //undefined
298 return syms.botType;
299 } else {
300 return new ArrayType(elemtype1, t.tsym, t.metadata) {
301 @Override
302 protected boolean needsStripping() {
303 return true;
304 }
305 };
306 }
307 }
308
309 @Override
310 public Type visitTypeVar(TypeVar t, ProjectionKind pkind) {
311 if (vars.contains(t)) {
312 if (seen.add(t)) {
313 try {
314 final Type bound;
315 switch (pkind) {
316 case UPWARDS:
317 bound = t.getUpperBound();
318 break;
319 case DOWNWARDS:
320 bound = (t.getLowerBound() == null) ?
321 syms.botType :
322 t.getLowerBound();
323 break;
324 default:
325 Assert.error();
326 return null;
327 }
328 return bound.map(this, pkind);
329 } finally {
330 seen.remove(t);
331 }
332 } else {
333 //cycle
334 return pkind == ProjectionKind.UPWARDS ?
335 syms.objectType : syms.botType;
336 }
337 } else {
338 return t;
339 }
340 }
341
342 private Type mapTypeArgument(Type site, Type declaredBound, Type t, ProjectionKind pkind) {
343 return t.containsAny(vars) ?
344 t.map(new TypeArgumentProjection(site, declaredBound), pkind) :
345 t;
346 }
347
348 class TypeArgumentProjection extends TypeMapping<ProjectionKind> {
349
350 Type site;
351 Type declaredBound;
352
353 TypeArgumentProjection(Type site, Type declaredBound) {
354 this.site = site;
355 this.declaredBound = declaredBound;
356 }
357
358 @Override
359 public Type visitType(Type t, ProjectionKind pkind) {
360 //type argument is some type containing restricted vars
361 if (pkind == ProjectionKind.DOWNWARDS) {
362 //not defined
363 return syms.botType;
364 }
365 Type upper = t.map(TypeProjection.this, ProjectionKind.UPWARDS);
366 Type lower = t.map(TypeProjection.this, ProjectionKind.DOWNWARDS);
367 List<Type> formals = site.tsym.type.getTypeArguments();
368 BoundKind bk;
369 Type bound;
370 if (!isSameType(upper, syms.objectType) &&
371 (declaredBound.containsAny(formals) ||
372 !isSubtype(declaredBound, upper))) {
373 bound = upper;
374 bk = EXTENDS;
375 } else if (!lower.hasTag(BOT)) {
376 bound = lower;
377 bk = SUPER;
378 } else {
379 bound = syms.objectType;
380 bk = UNBOUND;
381 }
382 return makeWildcard(bound, bk);
383 }
384
385 @Override
386 public Type visitWildcardType(WildcardType wt, ProjectionKind pkind) {
387 //type argument is some wildcard whose bound contains restricted vars
388 Type bound = syms.botType;
389 BoundKind bk = wt.kind;
390 switch (wt.kind) {
391 case EXTENDS:
392 bound = wt.type.map(TypeProjection.this, pkind);
393 if (bound.hasTag(BOT)) {
394 return syms.botType;
395 }
396 break;
397 case SUPER:
398 bound = wt.type.map(TypeProjection.this, pkind.complement());
399 if (bound.hasTag(BOT)) {
400 bound = syms.objectType;
401 bk = UNBOUND;
402 }
403 break;
404 }
405 return makeWildcard(bound, bk);
406 }
407
408 private Type makeWildcard(Type bound, BoundKind bk) {
409 return new WildcardType(bound, bk, syms.boundClass) {
410 @Override
411 protected boolean needsStripping() {
412 return true;
413 }
414 };
415 }
416 }
417 }
418
419 /**
420 * Computes an upward projection of given type, and vars. See {@link TypeProjection}.
421 *
422 * @param t the type to be projected
423 * @param vars the set of type variables to be mapped
424 * @return the type obtained as result of the projection
425 */
426 public Type upward(Type t, List<Type> vars) {
427 return t.map(new TypeProjection(vars), ProjectionKind.UPWARDS);
428 }
429
430 /**
431 * Computes the set of captured variables mentioned in a given type. See {@link CaptureScanner}.
432 * This routine is typically used to computed the input set of variables to be used during
433 * an upwards projection (see {@link Types#upward(Type, List)}).
434 *
435 * @param t the type where occurrences of captured variables have to be found
436 * @return the set of captured variables found in t
437 */
438 public List<Type> captures(Type t) {
439 CaptureScanner cs = new CaptureScanner();
440 Set<Type> captures = new HashSet<>();
441 cs.visit(t, captures);
442 return List.from(captures);
443 }
444
445 /**
446 * This visitor scans a type recursively looking for occurrences of captured type variables.
447 */
448 class CaptureScanner extends SimpleVisitor<Void, Set<Type>> {
449
450 @Override
451 public Void visitType(Type t, Set<Type> types) {
452 return null;
453 }
454
455 @Override
456 public Void visitClassType(ClassType t, Set<Type> seen) {
457 if (t.isCompound()) {
458 directSupertypes(t).forEach(s -> visit(s, seen));
459 } else {
460 t.allparams().forEach(ta -> visit(ta, seen));
461 }
462 return null;
463 }
464
465 @Override
466 public Void visitArrayType(ArrayType t, Set<Type> seen) {
467 return visit(t.elemtype, seen);
468 }
469
470 @Override
471 public Void visitWildcardType(WildcardType t, Set<Type> seen) {
472 visit(t.type, seen);
473 return null;
474 }
475
476 @Override
477 public Void visitTypeVar(TypeVar t, Set<Type> seen) {
478 if ((t.tsym.flags() & Flags.SYNTHETIC) != 0 && seen.add(t)) {
479 visit(t.getUpperBound(), seen);
480 }
481 return null;
482 }
483
484 @Override
485 public Void visitCapturedType(CapturedType t, Set<Type> seen) {
486 if (seen.add(t)) {
487 visit(t.getUpperBound(), seen);
488 visit(t.getLowerBound(), seen);
489 }
490 return null;
491 }
492 }
493
494 // </editor-fold>
495
496 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
497 /**
498 * Checks that all the arguments to a class are unbounded
499 * wildcards or something else that doesn't make any restrictions
500 * on the arguments. If a class isUnbounded, a raw super- or
501 * subclass can be cast to it without a warning.
502 * @param t a type
503 * @return true iff the given type is unbounded or raw
504 */
505 public boolean isUnbounded(Type t) {
506 return isUnbounded.visit(t);
507 }
508 // where
509 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
510
511 public Boolean visitType(Type t, Void ignored) {
512 return true;
513 }
514
515 @Override
516 public Boolean visitClassType(ClassType t, Void ignored) {
517 List<Type> parms = t.tsym.type.allparams();
518 List<Type> args = t.allparams();
519 while (parms.nonEmpty()) {
520 WildcardType unb = new WildcardType(syms.objectType,
521 BoundKind.UNBOUND,
522 syms.boundClass,
523 (TypeVar)parms.head);
524 if (!containsType(args.head, unb))
525 return false;
526 parms = parms.tail;
527 args = args.tail;
528 }
529 return true;
530 }
531 };
532 // </editor-fold>
533
534 // <editor-fold defaultstate="collapsed" desc="asSub">
535 /**
536 * Return the least specific subtype of t that starts with symbol
537 * sym. If none exists, return null. The least specific subtype
538 * is determined as follows:
539 *
540 * <p>If there is exactly one parameterized instance of sym that is a
541 * subtype of t, that parameterized instance is returned.<br>
542 * Otherwise, if the plain type or raw type `sym' is a subtype of
543 * type t, the type `sym' itself is returned. Otherwise, null is
544 * returned.
545 */
546 public Type asSub(Type t, Symbol sym) {
547 return asSub.visit(t, sym);
548 }
549 // where
550 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
551
552 public Type visitType(Type t, Symbol sym) {
553 return null;
554 }
555
556 @Override
557 public Type visitClassType(ClassType t, Symbol sym) {
558 if (t.tsym == sym)
559 return t;
560 Type base = asSuper(sym.type, t.tsym);
561 if (base == null)
562 return null;
563 ListBuffer<Type> from = new ListBuffer<>();
564 ListBuffer<Type> to = new ListBuffer<>();
565 try {
566 adapt(base, t, from, to);
567 } catch (AdaptFailure ex) {
568 return null;
569 }
570 Type res = subst(sym.type, from.toList(), to.toList());
571 if (!isSubtype(res, t))
572 return null;
573 ListBuffer<Type> openVars = new ListBuffer<>();
574 for (List<Type> l = sym.type.allparams();
575 l.nonEmpty(); l = l.tail)
576 if (res.contains(l.head) && !t.contains(l.head))
577 openVars.append(l.head);
578 if (openVars.nonEmpty()) {
579 if (t.isRaw()) {
580 // The subtype of a raw type is raw
581 res = erasure(res);
582 } else {
583 // Unbound type arguments default to ?
584 List<Type> opens = openVars.toList();
585 ListBuffer<Type> qs = new ListBuffer<>();
586 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
587 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND,
588 syms.boundClass, (TypeVar) iter.head));
589 }
590 res = subst(res, opens, qs.toList());
591 }
592 }
593 return res;
594 }
595
596 @Override
597 public Type visitErrorType(ErrorType t, Symbol sym) {
598 return t;
599 }
600 };
601 // </editor-fold>
602
603 // <editor-fold defaultstate="collapsed" desc="isConvertible">
604 /**
605 * Is t a subtype of or convertible via boxing/unboxing
606 * conversion to s?
607 */
608 public boolean isConvertible(Type t, Type s, Warner warn) {
609 if (t.hasTag(ERROR)) {
610 return true;
611 }
612 boolean tPrimitive = t.isPrimitive();
613 boolean sPrimitive = s.isPrimitive();
614 if (tPrimitive == sPrimitive) {
615 return isSubtypeUnchecked(t, s, warn);
616 }
617 boolean tUndet = t.hasTag(UNDETVAR);
618 boolean sUndet = s.hasTag(UNDETVAR);
619
620 if (tUndet || sUndet) {
621 return tUndet ?
622 isSubtype(t, boxedTypeOrType(s)) :
623 isSubtype(boxedTypeOrType(t), s);
624 }
625
626 return tPrimitive
627 ? isSubtype(boxedClass(t).type, s)
628 : isSubtype(unboxedType(t), s);
629 }
630
631 /**
632 * Is t a subtype of or convertible via boxing/unboxing
633 * conversions to s?
634 */
635 public boolean isConvertible(Type t, Type s) {
636 return isConvertible(t, s, noWarnings);
637 }
638 // </editor-fold>
639
640 // <editor-fold defaultstate="collapsed" desc="findSam">
641
642 /**
643 * Exception used to report a function descriptor lookup failure. The exception
644 * wraps a diagnostic that can be used to generate more details error
645 * messages.
646 */
647 public static class FunctionDescriptorLookupError extends CompilerInternalException {
648 private static final long serialVersionUID = 0;
649
650 transient JCDiagnostic diagnostic;
651
652 FunctionDescriptorLookupError(boolean dumpStackTraceOnError) {
653 super(dumpStackTraceOnError);
654 this.diagnostic = null;
655 }
656
657 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
658 this.diagnostic = diag;
659 return this;
660 }
661
662 public JCDiagnostic getDiagnostic() {
663 return diagnostic;
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(Types.this.dumpStacktraceOnError).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)) {
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)) {
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 /* there are three cases for ts and ss:
1681 * - one is a class and the other one is an interface (case I)
1682 * - both are classes (case II)
1683 * - both are interfaces (case III)
1684 * all those cases are covered in JLS 23, section: "5.1.6.1 Allowed Narrowing Reference Conversion"
1685 */
1686 private boolean areDisjoint(ClassSymbol ts, ClassSymbol ss) {
1687 Pair<ClassSymbol, ClassSymbol> newPair = new Pair<>(ts, ss);
1688 /* if we are seeing the same pair again then there is an issue with the sealed hierarchy
1689 * bail out, a detailed error will be reported downstream
1690 */
1691 if (!pairsSeen.add(newPair))
1692 return false;
1693
1694 if (ts.isInterface() != ss.isInterface()) { // case I: one is a class and the other one is an interface
1695 ClassSymbol isym = ts.isInterface() ? ts : ss; // isym is the interface and csym the class
1696 ClassSymbol csym = isym == ts ? ss : ts;
1697 if (!isSubtype(erasure(csym.type), erasure(isym.type))) {
1698 if (csym.isFinal()) {
1699 return true;
1700 } else if (csym.isSealed()) {
1701 return areDisjoint(isym, csym.getPermittedSubclasses());
1702 } else if (isym.isSealed()) {
1703 // if the class is not final and not sealed then it has to be freely extensible
1704 return areDisjoint(csym, isym.getPermittedSubclasses());
1705 }
1706 } // now both are classes or both are interfaces
1707 } else if (!ts.isInterface()) { // case II: both are classes
1708 return !isSubtype(erasure(ss.type), erasure(ts.type)) && !isSubtype(erasure(ts.type), erasure(ss.type));
1709 } else { // case III: both are interfaces
1710 if (!isSubtype(erasure(ts.type), erasure(ss.type)) && !isSubtype(erasure(ss.type), erasure(ts.type))) {
1711 if (ts.isSealed()) {
1712 return areDisjoint(ss, ts.getPermittedSubclasses());
1713 } else if (ss.isSealed()) {
1714 return areDisjoint(ts, ss.getPermittedSubclasses());
1715 }
1716 }
1717 }
1718 // at this point we haven't been able to statically prove that the classes or interfaces are disjoint
1719 return false;
1720 }
1721
1722 boolean areDisjoint(ClassSymbol csym, List<Type> permittedSubtypes) {
1723 return permittedSubtypes.stream().allMatch(psubtype -> areDisjoint(csym, (ClassSymbol) psubtype.tsym));
1724 }
1725 }
1726
1727 private TypeRelation isCastable = new TypeRelation() {
1728
1729 public Boolean visitType(Type t, Type s) {
1730 if (s.hasTag(ERROR) || t.hasTag(NONE))
1731 return true;
1732
1733 switch (t.getTag()) {
1734 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1735 case DOUBLE:
1736 return s.isNumeric();
1737 case BOOLEAN:
1738 return s.hasTag(BOOLEAN);
1739 case VOID:
1740 return false;
1741 case BOT:
1742 return isSubtype(t, s);
1743 default:
1744 throw new AssertionError();
1745 }
1746 }
1747
1748 @Override
1749 public Boolean visitWildcardType(WildcardType t, Type s) {
1750 return isCastable(wildUpperBound(t), s, warnStack.head);
1751 }
1752
1753 @Override
1754 public Boolean visitClassType(ClassType t, Type s) {
1755 if (s.hasTag(ERROR) || s.hasTag(BOT))
1756 return true;
1757
1758 if (s.hasTag(TYPEVAR)) {
1759 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1760 warnStack.head.warn(LintCategory.UNCHECKED);
1761 return true;
1762 } else {
1763 return false;
1764 }
1765 }
1766
1767 if (t.isCompound() || s.isCompound()) {
1768 return !t.isCompound() ?
1769 visitCompoundType((ClassType)s, t, true) :
1770 visitCompoundType(t, s, false);
1771 }
1772
1773 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) {
1774 boolean upcast;
1775 if ((upcast = isSubtype(erasure(t), erasure(s)))
1776 || isSubtype(erasure(s), erasure(t))) {
1777 if (!upcast && s.hasTag(ARRAY)) {
1778 if (!isReifiable(s))
1779 warnStack.head.warn(LintCategory.UNCHECKED);
1780 return true;
1781 } else if (s.isRaw()) {
1782 return true;
1783 } else if (t.isRaw()) {
1784 if (!isUnbounded(s))
1785 warnStack.head.warn(LintCategory.UNCHECKED);
1786 return true;
1787 }
1788 // Assume |a| <: |b|
1789 final Type a = upcast ? t : s;
1790 final Type b = upcast ? s : t;
1791 final boolean HIGH = true;
1792 final boolean LOW = false;
1793 final boolean DONT_REWRITE_TYPEVARS = false;
1794 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1795 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1796 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1797 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1798 Type lowSub = asSub(bLow, aLow.tsym);
1799 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1800 if (highSub == null) {
1801 final boolean REWRITE_TYPEVARS = true;
1802 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1803 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1804 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1805 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1806 lowSub = asSub(bLow, aLow.tsym);
1807 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1808 }
1809 if (highSub != null) {
1810 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1811 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1812 }
1813 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1814 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1815 && !disjointTypes(aLow.allparams(), highSub.allparams())
1816 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1817 if (upcast ? giveWarning(a, b) :
1818 giveWarning(b, a))
1819 warnStack.head.warn(LintCategory.UNCHECKED);
1820 return true;
1821 }
1822 }
1823 if (isReifiable(s))
1824 return isSubtypeUnchecked(a, b);
1825 else
1826 return isSubtypeUnchecked(a, b, warnStack.head);
1827 }
1828
1829 // Sidecast
1830 if (s.hasTag(CLASS)) {
1831 if ((s.tsym.flags() & INTERFACE) != 0) {
1832 return ((t.tsym.flags() & FINAL) == 0)
1833 ? sideCast(t, s, warnStack.head)
1834 : sideCastFinal(t, s, warnStack.head);
1835 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1836 return ((s.tsym.flags() & FINAL) == 0)
1837 ? sideCast(t, s, warnStack.head)
1838 : sideCastFinal(t, s, warnStack.head);
1839 } else {
1840 // unrelated class types
1841 return false;
1842 }
1843 }
1844 }
1845 return false;
1846 }
1847
1848 boolean visitCompoundType(ClassType ct, Type s, boolean reverse) {
1849 Warner warn = noWarnings;
1850 for (Type c : directSupertypes(ct)) {
1851 warn.clear();
1852 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1853 return false;
1854 }
1855 if (warn.hasLint(LintCategory.UNCHECKED))
1856 warnStack.head.warn(LintCategory.UNCHECKED);
1857 return true;
1858 }
1859
1860 @Override
1861 public Boolean visitArrayType(ArrayType t, Type s) {
1862 switch (s.getTag()) {
1863 case ERROR:
1864 case BOT:
1865 return true;
1866 case TYPEVAR:
1867 if (isCastable(s, t, noWarnings)) {
1868 warnStack.head.warn(LintCategory.UNCHECKED);
1869 return true;
1870 } else {
1871 return false;
1872 }
1873 case CLASS:
1874 return isSubtype(t, s);
1875 case ARRAY:
1876 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1877 return elemtype(t).hasTag(elemtype(s).getTag());
1878 } else {
1879 return isCastable(elemtype(t), elemtype(s), warnStack.head);
1880 }
1881 default:
1882 return false;
1883 }
1884 }
1885
1886 @Override
1887 public Boolean visitTypeVar(TypeVar t, Type s) {
1888 switch (s.getTag()) {
1889 case ERROR:
1890 case BOT:
1891 return true;
1892 case TYPEVAR:
1893 if (isSubtype(t, s)) {
1894 return true;
1895 } else if (isCastable(t.getUpperBound(), s, noWarnings)) {
1896 warnStack.head.warn(LintCategory.UNCHECKED);
1897 return true;
1898 } else {
1899 return false;
1900 }
1901 default:
1902 return isCastable(t.getUpperBound(), s, warnStack.head);
1903 }
1904 }
1905
1906 @Override
1907 public Boolean visitErrorType(ErrorType t, Type s) {
1908 return true;
1909 }
1910 };
1911 // </editor-fold>
1912
1913 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1914 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1915 while (ts.tail != null && ss.tail != null) {
1916 if (disjointType(ts.head, ss.head)) return true;
1917 ts = ts.tail;
1918 ss = ss.tail;
1919 }
1920 return false;
1921 }
1922
1923 /**
1924 * Two types or wildcards are considered disjoint if it can be
1925 * proven that no type can be contained in both. It is
1926 * conservative in that it is allowed to say that two types are
1927 * not disjoint, even though they actually are.
1928 *
1929 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1930 * {@code X} and {@code Y} are not disjoint.
1931 */
1932 public boolean disjointType(Type t, Type s) {
1933 return disjointType.visit(t, s);
1934 }
1935 // where
1936 private TypeRelation disjointType = new TypeRelation() {
1937
1938 private Set<TypePair> cache = new HashSet<>();
1939
1940 @Override
1941 public Boolean visitType(Type t, Type s) {
1942 if (s.hasTag(WILDCARD))
1943 return visit(s, t);
1944 else
1945 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1946 }
1947
1948 private boolean isCastableRecursive(Type t, Type s) {
1949 TypePair pair = new TypePair(t, s);
1950 if (cache.add(pair)) {
1951 try {
1952 return Types.this.isCastable(t, s);
1953 } finally {
1954 cache.remove(pair);
1955 }
1956 } else {
1957 return true;
1958 }
1959 }
1960
1961 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1962 TypePair pair = new TypePair(t, s);
1963 if (cache.add(pair)) {
1964 try {
1965 return Types.this.notSoftSubtype(t, s);
1966 } finally {
1967 cache.remove(pair);
1968 }
1969 } else {
1970 return false;
1971 }
1972 }
1973
1974 @Override
1975 public Boolean visitWildcardType(WildcardType t, Type s) {
1976 if (t.isUnbound())
1977 return false;
1978
1979 if (!s.hasTag(WILDCARD)) {
1980 if (t.isExtendsBound())
1981 return notSoftSubtypeRecursive(s, t.type);
1982 else
1983 return notSoftSubtypeRecursive(t.type, s);
1984 }
1985
1986 if (s.isUnbound())
1987 return false;
1988
1989 if (t.isExtendsBound()) {
1990 if (s.isExtendsBound())
1991 return !isCastableRecursive(t.type, wildUpperBound(s));
1992 else if (s.isSuperBound())
1993 return notSoftSubtypeRecursive(wildLowerBound(s), t.type);
1994 } else if (t.isSuperBound()) {
1995 if (s.isExtendsBound())
1996 return notSoftSubtypeRecursive(t.type, wildUpperBound(s));
1997 }
1998 return false;
1999 }
2000 };
2001 // </editor-fold>
2002
2003 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds">
2004 public List<Type> cvarLowerBounds(List<Type> ts) {
2005 return ts.map(cvarLowerBoundMapping);
2006 }
2007 private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() {
2008 @Override
2009 public Type visitCapturedType(CapturedType t, Void _unused) {
2010 return cvarLowerBound(t);
2011 }
2012 };
2013 // </editor-fold>
2014
2015 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
2016 /**
2017 * This relation answers the question: is impossible that
2018 * something of type `t' can be a subtype of `s'? This is
2019 * different from the question "is `t' not a subtype of `s'?"
2020 * when type variables are involved: Integer is not a subtype of T
2021 * where {@code <T extends Number>} but it is not true that Integer cannot
2022 * possibly be a subtype of T.
2023 */
2024 public boolean notSoftSubtype(Type t, Type s) {
2025 if (t == s) return false;
2026 if (t.hasTag(TYPEVAR)) {
2027 TypeVar tv = (TypeVar) t;
2028 return !isCastable(tv.getUpperBound(),
2029 relaxBound(s),
2030 noWarnings);
2031 }
2032 if (!s.hasTag(WILDCARD))
2033 s = cvarUpperBound(s);
2034
2035 return !isSubtype(t, relaxBound(s));
2036 }
2037
2038 private Type relaxBound(Type t) {
2039 return (t.hasTag(TYPEVAR)) ?
2040 rewriteQuantifiers(skipTypeVars(t, false), true, true) :
2041 t;
2042 }
2043 // </editor-fold>
2044
2045 // <editor-fold defaultstate="collapsed" desc="isReifiable">
2046 public boolean isReifiable(Type t) {
2047 return isReifiable.visit(t);
2048 }
2049 // where
2050 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
2051
2052 public Boolean visitType(Type t, Void ignored) {
2053 return true;
2054 }
2055
2056 @Override
2057 public Boolean visitClassType(ClassType t, Void ignored) {
2058 if (t.isCompound())
2059 return false;
2060 else {
2061 if (!t.isParameterized())
2062 return true;
2063
2064 for (Type param : t.allparams()) {
2065 if (!param.isUnbound())
2066 return false;
2067 }
2068 return true;
2069 }
2070 }
2071
2072 @Override
2073 public Boolean visitArrayType(ArrayType t, Void ignored) {
2074 return visit(t.elemtype);
2075 }
2076
2077 @Override
2078 public Boolean visitTypeVar(TypeVar t, Void ignored) {
2079 return false;
2080 }
2081 };
2082 // </editor-fold>
2083
2084 // <editor-fold defaultstate="collapsed" desc="Array Utils">
2085 public boolean isArray(Type t) {
2086 while (t.hasTag(WILDCARD))
2087 t = wildUpperBound(t);
2088 return t.hasTag(ARRAY);
2089 }
2090
2091 /**
2092 * The element type of an array.
2093 */
2094 public Type elemtype(Type t) {
2095 switch (t.getTag()) {
2096 case WILDCARD:
2097 return elemtype(wildUpperBound(t));
2098 case ARRAY:
2099 return ((ArrayType)t).elemtype;
2100 case FORALL:
2101 return elemtype(((ForAll)t).qtype);
2102 case ERROR:
2103 return t;
2104 default:
2105 return null;
2106 }
2107 }
2108
2109 public Type elemtypeOrType(Type t) {
2110 Type elemtype = elemtype(t);
2111 return elemtype != null ?
2112 elemtype :
2113 t;
2114 }
2115
2116 /**
2117 * Mapping to take element type of an arraytype
2118 */
2119 private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() {
2120 @Override
2121 public Type visitArrayType(ArrayType t, Void _unused) {
2122 return t.elemtype;
2123 }
2124
2125 @Override
2126 public Type visitTypeVar(TypeVar t, Void _unused) {
2127 return visit(skipTypeVars(t, false));
2128 }
2129 };
2130
2131 /**
2132 * The number of dimensions of an array type.
2133 */
2134 public int dimensions(Type t) {
2135 int result = 0;
2136 while (t.hasTag(ARRAY)) {
2137 result++;
2138 t = elemtype(t);
2139 }
2140 return result;
2141 }
2142
2143 /**
2144 * Returns an ArrayType with the component type t
2145 *
2146 * @param t The component type of the ArrayType
2147 * @return the ArrayType for the given component
2148 */
2149 public ArrayType makeArrayType(Type t) {
2150 return makeArrayType(t, 1);
2151 }
2152
2153 public ArrayType makeArrayType(Type t, int dimensions) {
2154 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) {
2155 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
2156 }
2157 ArrayType result = new ArrayType(t, syms.arrayClass);
2158 for (int i = 1; i < dimensions; i++) {
2159 result = new ArrayType(result, syms.arrayClass);
2160 }
2161 return result;
2162 }
2163 // </editor-fold>
2164
2165 // <editor-fold defaultstate="collapsed" desc="asSuper">
2166 /**
2167 * Return the (most specific) base type of t that starts with the
2168 * given symbol. If none exists, return null.
2169 *
2170 * Caveat Emptor: Since javac represents the class of all arrays with a singleton
2171 * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant,
2172 * this method could yield surprising answers when invoked on arrays. For example when
2173 * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null.
2174 *
2175 * @param t a type
2176 * @param sym a symbol
2177 */
2178 public Type asSuper(Type t, Symbol sym) {
2179 /* Some examples:
2180 *
2181 * (Enum<E>, Comparable) => Comparable<E>
2182 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind>
2183 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree
2184 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) =>
2185 * Iterable<capture#160 of ? extends c.s.s.d.DocTree>
2186 */
2187 if (sym.type == syms.objectType) { //optimization
2188 return syms.objectType;
2189 }
2190 return asSuper.visit(t, sym);
2191 }
2192 // where
2193 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
2194
2195 private Set<Symbol> seenTypes = new HashSet<>();
2196
2197 public Type visitType(Type t, Symbol sym) {
2198 return null;
2199 }
2200
2201 @Override
2202 public Type visitClassType(ClassType t, Symbol sym) {
2203 if (t.tsym == sym)
2204 return t;
2205
2206 Symbol c = t.tsym;
2207 if (!seenTypes.add(c)) {
2208 return null;
2209 }
2210 try {
2211 Type st = supertype(t);
2212 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) {
2213 Type x = asSuper(st, sym);
2214 if (x != null)
2215 return x;
2216 }
2217 if ((sym.flags() & INTERFACE) != 0) {
2218 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
2219 if (!l.head.hasTag(ERROR)) {
2220 Type x = asSuper(l.head, sym);
2221 if (x != null)
2222 return x;
2223 }
2224 }
2225 }
2226 return null;
2227 } finally {
2228 seenTypes.remove(c);
2229 }
2230 }
2231
2232 @Override
2233 public Type visitArrayType(ArrayType t, Symbol sym) {
2234 return isSubtype(t, sym.type) ? sym.type : null;
2235 }
2236
2237 @Override
2238 public Type visitTypeVar(TypeVar t, Symbol sym) {
2239 if (t.tsym == sym)
2240 return t;
2241 else
2242 return asSuper(t.getUpperBound(), sym);
2243 }
2244
2245 @Override
2246 public Type visitErrorType(ErrorType t, Symbol sym) {
2247 return t;
2248 }
2249 };
2250
2251 /**
2252 * Return the base type of t or any of its outer types that starts
2253 * with the given symbol. If none exists, return null.
2254 *
2255 * @param t a type
2256 * @param sym a symbol
2257 */
2258 public Type asOuterSuper(Type t, Symbol sym) {
2259 switch (t.getTag()) {
2260 case CLASS:
2261 do {
2262 Type s = asSuper(t, sym);
2263 if (s != null) return s;
2264 t = t.getEnclosingType();
2265 } while (t.hasTag(CLASS));
2266 return null;
2267 case ARRAY:
2268 return isSubtype(t, sym.type) ? sym.type : null;
2269 case TYPEVAR:
2270 return asSuper(t, sym);
2271 case ERROR:
2272 return t;
2273 default:
2274 return null;
2275 }
2276 }
2277
2278 /**
2279 * Return the base type of t or any of its enclosing types that
2280 * starts with the given symbol. If none exists, return null.
2281 *
2282 * @param t a type
2283 * @param sym a symbol
2284 */
2285 public Type asEnclosingSuper(Type t, Symbol sym) {
2286 switch (t.getTag()) {
2287 case CLASS:
2288 do {
2289 Type s = asSuper(t, sym);
2290 if (s != null) return s;
2291 Type outer = t.getEnclosingType();
2292 t = (outer.hasTag(CLASS)) ? outer :
2293 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
2294 Type.noType;
2295 } while (t.hasTag(CLASS));
2296 return null;
2297 case ARRAY:
2298 return isSubtype(t, sym.type) ? sym.type : null;
2299 case TYPEVAR:
2300 return asSuper(t, sym);
2301 case ERROR:
2302 return t;
2303 default:
2304 return null;
2305 }
2306 }
2307 // </editor-fold>
2308
2309 // <editor-fold defaultstate="collapsed" desc="memberType">
2310 /**
2311 * The type of given symbol, seen as a member of t.
2312 *
2313 * @param t a type
2314 * @param sym a symbol
2315 */
2316 public Type memberType(Type t, Symbol sym) {
2317 return (sym.flags() & STATIC) != 0
2318 ? sym.type
2319 : memberType.visit(t, sym);
2320 }
2321 // where
2322 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
2323
2324 public Type visitType(Type t, Symbol sym) {
2325 return sym.type;
2326 }
2327
2328 @Override
2329 public Type visitWildcardType(WildcardType t, Symbol sym) {
2330 return memberType(wildUpperBound(t), sym);
2331 }
2332
2333 @Override
2334 public Type visitClassType(ClassType t, Symbol sym) {
2335 Symbol owner = sym.owner;
2336 long flags = sym.flags();
2337 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
2338 Type base = asOuterSuper(t, owner);
2339 //if t is an intersection type T = CT & I1 & I2 ... & In
2340 //its supertypes CT, I1, ... In might contain wildcards
2341 //so we need to go through capture conversion
2342 base = t.isCompound() ? capture(base) : base;
2343 if (base != null) {
2344 List<Type> ownerParams = owner.type.allparams();
2345 List<Type> baseParams = base.allparams();
2346 if (ownerParams.nonEmpty()) {
2347 if (baseParams.isEmpty()) {
2348 // then base is a raw type
2349 return erasure(sym.type);
2350 } else {
2351 return subst(sym.type, ownerParams, baseParams);
2352 }
2353 }
2354 }
2355 }
2356 return sym.type;
2357 }
2358
2359 @Override
2360 public Type visitTypeVar(TypeVar t, Symbol sym) {
2361 return memberType(t.getUpperBound(), sym);
2362 }
2363
2364 @Override
2365 public Type visitErrorType(ErrorType t, Symbol sym) {
2366 return t;
2367 }
2368 };
2369 // </editor-fold>
2370
2371 // <editor-fold defaultstate="collapsed" desc="isAssignable">
2372 public boolean isAssignable(Type t, Type s) {
2373 return isAssignable(t, s, noWarnings);
2374 }
2375
2376 /**
2377 * Is t assignable to s?<br>
2378 * Equivalent to subtype except for constant values and raw
2379 * types.<br>
2380 * (not defined for Method and ForAll types)
2381 */
2382 public boolean isAssignable(Type t, Type s, Warner warn) {
2383 if (t.hasTag(ERROR))
2384 return true;
2385 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) {
2386 int value = ((Number)t.constValue()).intValue();
2387 switch (s.getTag()) {
2388 case BYTE:
2389 case CHAR:
2390 case SHORT:
2391 case INT:
2392 if (s.getTag().checkRange(value))
2393 return true;
2394 break;
2395 case CLASS:
2396 switch (unboxedType(s).getTag()) {
2397 case BYTE:
2398 case CHAR:
2399 case SHORT:
2400 return isAssignable(t, unboxedType(s), warn);
2401 }
2402 break;
2403 }
2404 }
2405 return isConvertible(t, s, warn);
2406 }
2407 // </editor-fold>
2408
2409 // <editor-fold defaultstate="collapsed" desc="erasure">
2410 /**
2411 * The erasure of t {@code |t|} -- the type that results when all
2412 * type parameters in t are deleted.
2413 */
2414 public Type erasure(Type t) {
2415 return eraseNotNeeded(t) ? t : erasure(t, false);
2416 }
2417 //where
2418 private boolean eraseNotNeeded(Type t) {
2419 // We don't want to erase primitive types and String type as that
2420 // operation is idempotent. Also, erasing these could result in loss
2421 // of information such as constant values attached to such types.
2422 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2423 }
2424
2425 private Type erasure(Type t, boolean recurse) {
2426 if (t.isPrimitive()) {
2427 return t; /* fast special case */
2428 } else {
2429 Type out = erasure.visit(t, recurse);
2430 return out;
2431 }
2432 }
2433 // where
2434 private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() {
2435 @SuppressWarnings("fallthrough")
2436 private Type combineMetadata(final Type s,
2437 final Type t) {
2438 if (t.getMetadata().nonEmpty()) {
2439 switch (s.getTag()) {
2440 case CLASS:
2441 if (s instanceof UnionClassType ||
2442 s instanceof IntersectionClassType) {
2443 return s;
2444 }
2445 //fall-through
2446 case BYTE, CHAR, SHORT, LONG, FLOAT, INT, DOUBLE, BOOLEAN,
2447 ARRAY, MODULE, TYPEVAR, WILDCARD, BOT:
2448 return s.dropMetadata(Annotations.class);
2449 case VOID, METHOD, PACKAGE, FORALL, DEFERRED,
2450 NONE, ERROR, UNDETVAR, UNINITIALIZED_THIS,
2451 UNINITIALIZED_OBJECT:
2452 return s;
2453 default:
2454 throw new AssertionError(s.getTag().name());
2455 }
2456 } else {
2457 return s;
2458 }
2459 }
2460
2461 public Type visitType(Type t, Boolean recurse) {
2462 if (t.isPrimitive())
2463 return t; /*fast special case*/
2464 else {
2465 //other cases already handled
2466 return combineMetadata(t, t);
2467 }
2468 }
2469
2470 @Override
2471 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2472 Type erased = erasure(wildUpperBound(t), recurse);
2473 return combineMetadata(erased, t);
2474 }
2475
2476 @Override
2477 public Type visitClassType(ClassType t, Boolean recurse) {
2478 Type erased = t.tsym.erasure(Types.this);
2479 if (recurse) {
2480 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym,
2481 t.dropMetadata(Annotations.class).getMetadata());
2482 return erased;
2483 } else {
2484 return combineMetadata(erased, t);
2485 }
2486 }
2487
2488 @Override
2489 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2490 Type erased = erasure(t.getUpperBound(), recurse);
2491 return combineMetadata(erased, t);
2492 }
2493 };
2494
2495 public List<Type> erasure(List<Type> ts) {
2496 return erasure.visit(ts, false);
2497 }
2498
2499 public Type erasureRecursive(Type t) {
2500 return erasure(t, true);
2501 }
2502
2503 public List<Type> erasureRecursive(List<Type> ts) {
2504 return erasure.visit(ts, true);
2505 }
2506 // </editor-fold>
2507
2508 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType">
2509 /**
2510 * Make an intersection type from non-empty list of types. The list should be ordered according to
2511 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion.
2512 * Hence, this version of makeIntersectionType may not be called during a classfile read.
2513 *
2514 * @param bounds the types from which the intersection type is formed
2515 */
2516 public IntersectionClassType makeIntersectionType(List<Type> bounds) {
2517 return makeIntersectionType(bounds, bounds.head.tsym.isInterface());
2518 }
2519
2520 /**
2521 * Make an intersection type from non-empty list of types. The list should be ordered according to
2522 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as
2523 * an extra parameter indicates as to whether all bounds are interfaces - in which case the
2524 * supertype is implicitly assumed to be 'Object'.
2525 *
2526 * @param bounds the types from which the intersection type is formed
2527 * @param allInterfaces are all bounds interface types?
2528 */
2529 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) {
2530 Assert.check(bounds.nonEmpty());
2531 Type firstExplicitBound = bounds.head;
2532 if (allInterfaces) {
2533 bounds = bounds.prepend(syms.objectType);
2534 }
2535 ClassSymbol bc =
2536 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2537 Type.moreInfo
2538 ? names.fromString(bounds.toString())
2539 : names.empty,
2540 null,
2541 syms.noSymbol);
2542 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces);
2543 bc.type = intersectionType;
2544 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
2545 syms.objectType : // error condition, recover
2546 erasure(firstExplicitBound);
2547 bc.members_field = WriteableScope.create(bc);
2548 return intersectionType;
2549 }
2550 // </editor-fold>
2551
2552 // <editor-fold defaultstate="collapsed" desc="supertype">
2553 public Type supertype(Type t) {
2554 return supertype.visit(t);
2555 }
2556 // where
2557 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2558
2559 public Type visitType(Type t, Void ignored) {
2560 // A note on wildcards: there is no good way to
2561 // determine a supertype for a lower-bounded wildcard.
2562 return Type.noType;
2563 }
2564
2565 @Override
2566 public Type visitClassType(ClassType t, Void ignored) {
2567 if (t.supertype_field == null) {
2568 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2569 // An interface has no superclass; its supertype is Object.
2570 if (t.isInterface())
2571 supertype = ((ClassType)t.tsym.type).supertype_field;
2572 if (t.supertype_field == null) {
2573 List<Type> actuals = classBound(t).allparams();
2574 List<Type> formals = t.tsym.type.allparams();
2575 if (t.hasErasedSupertypes()) {
2576 t.supertype_field = erasureRecursive(supertype);
2577 } else if (formals.nonEmpty()) {
2578 t.supertype_field = subst(supertype, formals, actuals);
2579 }
2580 else {
2581 t.supertype_field = supertype;
2582 }
2583 }
2584 }
2585 return t.supertype_field;
2586 }
2587
2588 /**
2589 * The supertype is always a class type. If the type
2590 * variable's bounds start with a class type, this is also
2591 * the supertype. Otherwise, the supertype is
2592 * java.lang.Object.
2593 */
2594 @Override
2595 public Type visitTypeVar(TypeVar t, Void ignored) {
2596 if (t.getUpperBound().hasTag(TYPEVAR) ||
2597 (!t.getUpperBound().isCompound() && !t.getUpperBound().isInterface())) {
2598 return t.getUpperBound();
2599 } else {
2600 return supertype(t.getUpperBound());
2601 }
2602 }
2603
2604 @Override
2605 public Type visitArrayType(ArrayType t, Void ignored) {
2606 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2607 return arraySuperType();
2608 else
2609 return new ArrayType(supertype(t.elemtype), t.tsym);
2610 }
2611
2612 @Override
2613 public Type visitErrorType(ErrorType t, Void ignored) {
2614 return Type.noType;
2615 }
2616 };
2617 // </editor-fold>
2618
2619 // <editor-fold defaultstate="collapsed" desc="interfaces">
2620 /**
2621 * Return the interfaces implemented by this class.
2622 */
2623 public List<Type> interfaces(Type t) {
2624 return interfaces.visit(t);
2625 }
2626 // where
2627 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2628
2629 public List<Type> visitType(Type t, Void ignored) {
2630 return List.nil();
2631 }
2632
2633 @Override
2634 public List<Type> visitClassType(ClassType t, Void ignored) {
2635 if (t.interfaces_field == null) {
2636 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2637 if (t.interfaces_field == null) {
2638 // If t.interfaces_field is null, then t must
2639 // be a parameterized type (not to be confused
2640 // with a generic type declaration).
2641 // Terminology:
2642 // Parameterized type: List<String>
2643 // Generic type declaration: class List<E> { ... }
2644 // So t corresponds to List<String> and
2645 // t.tsym.type corresponds to List<E>.
2646 // The reason t must be parameterized type is
2647 // that completion will happen as a side
2648 // effect of calling
2649 // ClassSymbol.getInterfaces. Since
2650 // t.interfaces_field is null after
2651 // completion, we can assume that t is not the
2652 // type of a class/interface declaration.
2653 Assert.check(t != t.tsym.type, t);
2654 List<Type> actuals = t.allparams();
2655 List<Type> formals = t.tsym.type.allparams();
2656 if (t.hasErasedSupertypes()) {
2657 t.interfaces_field = erasureRecursive(interfaces);
2658 } else if (formals.nonEmpty()) {
2659 t.interfaces_field = subst(interfaces, formals, actuals);
2660 }
2661 else {
2662 t.interfaces_field = interfaces;
2663 }
2664 }
2665 }
2666 return t.interfaces_field;
2667 }
2668
2669 @Override
2670 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2671 if (t.getUpperBound().isCompound())
2672 return interfaces(t.getUpperBound());
2673
2674 if (t.getUpperBound().isInterface())
2675 return List.of(t.getUpperBound());
2676
2677 return List.nil();
2678 }
2679 };
2680
2681 public List<Type> directSupertypes(Type t) {
2682 return directSupertypes.visit(t);
2683 }
2684 // where
2685 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() {
2686
2687 public List<Type> visitType(final Type type, final Void ignored) {
2688 if (!type.isIntersection()) {
2689 final Type sup = supertype(type);
2690 return (sup == Type.noType || sup == type || sup == null)
2691 ? interfaces(type)
2692 : interfaces(type).prepend(sup);
2693 } else {
2694 return ((IntersectionClassType)type).getExplicitComponents();
2695 }
2696 }
2697 };
2698
2699 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2700 for (Type i2 : interfaces(origin.type)) {
2701 if (isym == i2.tsym) return true;
2702 }
2703 return false;
2704 }
2705 // </editor-fold>
2706
2707 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2708 Map<Type,Boolean> isDerivedRawCache = new HashMap<>();
2709
2710 public boolean isDerivedRaw(Type t) {
2711 Boolean result = isDerivedRawCache.get(t);
2712 if (result == null) {
2713 result = isDerivedRawInternal(t);
2714 isDerivedRawCache.put(t, result);
2715 }
2716 return result;
2717 }
2718
2719 public boolean isDerivedRawInternal(Type t) {
2720 if (t.isErroneous())
2721 return false;
2722 return
2723 t.isRaw() ||
2724 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) ||
2725 isDerivedRaw(interfaces(t));
2726 }
2727
2728 public boolean isDerivedRaw(List<Type> ts) {
2729 List<Type> l = ts;
2730 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2731 return l.nonEmpty();
2732 }
2733 // </editor-fold>
2734
2735 // <editor-fold defaultstate="collapsed" desc="setBounds">
2736 /**
2737 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly,
2738 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise
2739 * the supertype is simply left null (in this case, the supertype is assumed to be the head of
2740 * the bound list passed as second argument). Note that this check might cause a symbol completion.
2741 * Hence, this version of setBounds may not be called during a classfile read.
2742 *
2743 * @param t a type variable
2744 * @param bounds the bounds, must be nonempty
2745 */
2746 public void setBounds(TypeVar t, List<Type> bounds) {
2747 setBounds(t, bounds, bounds.head.tsym.isInterface());
2748 }
2749
2750 /**
2751 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds.
2752 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds
2753 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'.
2754 *
2755 * @param t a type variable
2756 * @param bounds the bounds, must be nonempty
2757 * @param allInterfaces are all bounds interface types?
2758 */
2759 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2760 t.setUpperBound( bounds.tail.isEmpty() ?
2761 bounds.head :
2762 makeIntersectionType(bounds, allInterfaces) );
2763 t.rank_field = -1;
2764 }
2765 // </editor-fold>
2766
2767 // <editor-fold defaultstate="collapsed" desc="getBounds">
2768 /**
2769 * Return list of bounds of the given type variable.
2770 */
2771 public List<Type> getBounds(TypeVar t) {
2772 if (t.getUpperBound().hasTag(NONE))
2773 return List.nil();
2774 else if (t.getUpperBound().isErroneous() || !t.getUpperBound().isCompound())
2775 return List.of(t.getUpperBound());
2776 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2777 return interfaces(t).prepend(supertype(t));
2778 else
2779 // No superclass was given in bounds.
2780 // In this case, supertype is Object, erasure is first interface.
2781 return interfaces(t);
2782 }
2783 // </editor-fold>
2784
2785 // <editor-fold defaultstate="collapsed" desc="classBound">
2786 /**
2787 * If the given type is a (possibly selected) type variable,
2788 * return the bounding class of this type, otherwise return the
2789 * type itself.
2790 */
2791 public Type classBound(Type t) {
2792 return classBound.visit(t);
2793 }
2794 // where
2795 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2796
2797 public Type visitType(Type t, Void ignored) {
2798 return t;
2799 }
2800
2801 @Override
2802 public Type visitClassType(ClassType t, Void ignored) {
2803 Type outer1 = classBound(t.getEnclosingType());
2804 if (outer1 != t.getEnclosingType())
2805 return new ClassType(outer1, t.getTypeArguments(), t.tsym,
2806 t.getMetadata());
2807 else
2808 return t;
2809 }
2810
2811 @Override
2812 public Type visitTypeVar(TypeVar t, Void ignored) {
2813 return classBound(supertype(t));
2814 }
2815
2816 @Override
2817 public Type visitErrorType(ErrorType t, Void ignored) {
2818 return t;
2819 }
2820 };
2821 // </editor-fold>
2822
2823 // <editor-fold defaultstate="collapsed" desc="subsignature / override equivalence">
2824 /**
2825 * Returns true iff the first signature is a <em>subsignature</em>
2826 * of the other. This is <b>not</b> an equivalence
2827 * relation.
2828 *
2829 * @jls 8.4.2 Method Signature
2830 * @see #overrideEquivalent(Type t, Type s)
2831 * @param t first signature (possibly raw).
2832 * @param s second signature (could be subjected to erasure).
2833 * @return true if t is a subsignature of s.
2834 */
2835 public boolean isSubSignature(Type t, Type s) {
2836 return hasSameArgs(t, s, true) || hasSameArgs(t, erasure(s), true);
2837 }
2838
2839 /**
2840 * Returns true iff these signatures are related by <em>override
2841 * equivalence</em>. This is the natural extension of
2842 * isSubSignature to an equivalence relation.
2843 *
2844 * @jls 8.4.2 Method Signature
2845 * @see #isSubSignature(Type t, Type s)
2846 * @param t a signature (possible raw, could be subjected to
2847 * erasure).
2848 * @param s a signature (possible raw, could be subjected to
2849 * erasure).
2850 * @return true if either argument is a subsignature of the other.
2851 */
2852 public boolean overrideEquivalent(Type t, Type s) {
2853 return hasSameArgs(t, s) ||
2854 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2855 }
2856
2857 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2858 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) {
2859 if (msym.overrides(sym, origin, Types.this, true)) {
2860 return true;
2861 }
2862 }
2863 return false;
2864 }
2865
2866 /**
2867 * This enum defines the strategy for implementing most specific return type check
2868 * during the most specific and functional interface checks.
2869 */
2870 public enum MostSpecificReturnCheck {
2871 /**
2872 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling
2873 * method type variables (if either method is generic) and (ii) subtyping should be replaced
2874 * by type-equivalence for primitives. This is essentially an inlined version of
2875 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been
2876 * replaced with a strict subtyping check.
2877 */
2878 BASIC() {
2879 @Override
2880 public boolean test(Type mt1, Type mt2, Types types) {
2881 List<Type> tvars = mt1.getTypeArguments();
2882 List<Type> svars = mt2.getTypeArguments();
2883 Type t = mt1.getReturnType();
2884 Type s = types.subst(mt2.getReturnType(), svars, tvars);
2885 return types.isSameType(t, s) ||
2886 !t.isPrimitive() &&
2887 !s.isPrimitive() &&
2888 types.isSubtype(t, s);
2889 }
2890 },
2891 /**
2892 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2.
2893 */
2894 RTS() {
2895 @Override
2896 public boolean test(Type mt1, Type mt2, Types types) {
2897 return types.returnTypeSubstitutable(mt1, mt2);
2898 }
2899 };
2900
2901 public abstract boolean test(Type mt1, Type mt2, Types types);
2902 }
2903
2904 /**
2905 * Merge multiple abstract methods. The preferred method is a method that is a subsignature
2906 * of all the other signatures and whose return type is more specific {@link MostSpecificReturnCheck}.
2907 * The resulting preferred method has a throws clause that is the intersection of the merged
2908 * methods' clauses.
2909 */
2910 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) {
2911 //first check for preconditions
2912 boolean shouldErase = false;
2913 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes();
2914 for (Symbol s : ambiguousInOrder) {
2915 if ((s.flags() & ABSTRACT) == 0 ||
2916 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) {
2917 return Optional.empty();
2918 } else if (s.type.hasTag(FORALL)) {
2919 shouldErase = true;
2920 }
2921 }
2922 //then merge abstracts
2923 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) {
2924 outer: for (Symbol s : ambiguousInOrder) {
2925 Type mt = memberType(site, s);
2926 List<Type> allThrown = mt.getThrownTypes();
2927 for (Symbol s2 : ambiguousInOrder) {
2928 if (s != s2) {
2929 Type mt2 = memberType(site, s2);
2930 if (!isSubSignature(mt, mt2) ||
2931 !mostSpecificReturnCheck.test(mt, mt2, this)) {
2932 //ambiguity cannot be resolved
2933 continue outer;
2934 } else {
2935 List<Type> thrownTypes2 = mt2.getThrownTypes();
2936 if (!mt.hasTag(FORALL) && shouldErase) {
2937 thrownTypes2 = erasure(thrownTypes2);
2938 } else if (mt.hasTag(FORALL)) {
2939 //subsignature implies that if most specific is generic, then all other
2940 //methods are too
2941 Assert.check(mt2.hasTag(FORALL));
2942 // if both are generic methods, adjust thrown types ahead of intersection computation
2943 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments());
2944 }
2945 allThrown = chk.intersect(allThrown, thrownTypes2);
2946 }
2947 }
2948 }
2949 return (allThrown == mt.getThrownTypes()) ?
2950 Optional.of(s) :
2951 Optional.of(new MethodSymbol(
2952 s.flags(),
2953 s.name,
2954 createMethodTypeWithThrown(s.type, allThrown),
2955 s.owner) {
2956 @Override
2957 public Symbol baseSymbol() {
2958 return s;
2959 }
2960 });
2961 }
2962 }
2963 return Optional.empty();
2964 }
2965
2966 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2967 class ImplementationCache {
2968
2969 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>();
2970
2971 class Entry {
2972 final MethodSymbol cachedImpl;
2973 final Predicate<Symbol> implFilter;
2974 final boolean checkResult;
2975 final int prevMark;
2976
2977 public Entry(MethodSymbol cachedImpl,
2978 Predicate<Symbol> scopeFilter,
2979 boolean checkResult,
2980 int prevMark) {
2981 this.cachedImpl = cachedImpl;
2982 this.implFilter = scopeFilter;
2983 this.checkResult = checkResult;
2984 this.prevMark = prevMark;
2985 }
2986
2987 boolean matches(Predicate<Symbol> scopeFilter, boolean checkResult, int mark) {
2988 return this.implFilter == scopeFilter &&
2989 this.checkResult == checkResult &&
2990 this.prevMark == mark;
2991 }
2992 }
2993
2994 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2995 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2996 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2997 if (cache == null) {
2998 cache = new HashMap<>();
2999 _map.put(ms, new SoftReference<>(cache));
3000 }
3001 Entry e = cache.get(origin);
3002 CompoundScope members = membersClosure(origin.type, true);
3003 if (e == null ||
3004 !e.matches(implFilter, checkResult, members.getMark())) {
3005 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
3006 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
3007 return impl;
3008 }
3009 else {
3010 return e.cachedImpl;
3011 }
3012 }
3013
3014 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
3015 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
3016 t = skipTypeVars(t, false);
3017 TypeSymbol c = t.tsym;
3018 Symbol bestSoFar = null;
3019 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) {
3020 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) {
3021 bestSoFar = sym;
3022 if ((sym.flags() & ABSTRACT) == 0) {
3023 //if concrete impl is found, exit immediately
3024 break;
3025 }
3026 }
3027 }
3028 if (bestSoFar != null) {
3029 //return either the (only) concrete implementation or the first abstract one
3030 return (MethodSymbol)bestSoFar;
3031 }
3032 }
3033 return null;
3034 }
3035 }
3036
3037 private ImplementationCache implCache = new ImplementationCache();
3038
3039 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
3040 return implCache.get(ms, origin, checkResult, implFilter);
3041 }
3042 // </editor-fold>
3043
3044 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
3045 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> {
3046
3047 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>();
3048
3049 Set<TypeSymbol> seenTypes = new HashSet<>();
3050
3051 class MembersScope extends CompoundScope {
3052
3053 CompoundScope scope;
3054
3055 public MembersScope(CompoundScope scope) {
3056 super(scope.owner);
3057 this.scope = scope;
3058 }
3059
3060 Predicate<Symbol> combine(Predicate<Symbol> sf) {
3061 return s -> !s.owner.isInterface() && (sf == null || sf.test(s));
3062 }
3063
3064 @Override
3065 public Iterable<Symbol> getSymbols(Predicate<Symbol> sf, LookupKind lookupKind) {
3066 return scope.getSymbols(combine(sf), lookupKind);
3067 }
3068
3069 @Override
3070 public Iterable<Symbol> getSymbolsByName(Name name, Predicate<Symbol> sf, LookupKind lookupKind) {
3071 return scope.getSymbolsByName(name, combine(sf), lookupKind);
3072 }
3073
3074 @Override
3075 public int getMark() {
3076 return scope.getMark();
3077 }
3078 }
3079
3080 CompoundScope nilScope;
3081
3082 /** members closure visitor methods **/
3083
3084 public CompoundScope visitType(Type t, Void _unused) {
3085 if (nilScope == null) {
3086 nilScope = new CompoundScope(syms.noSymbol);
3087 }
3088 return nilScope;
3089 }
3090
3091 @Override
3092 public CompoundScope visitClassType(ClassType t, Void _unused) {
3093 if (!seenTypes.add(t.tsym)) {
3094 //this is possible when an interface is implemented in multiple
3095 //superclasses, or when a class hierarchy is circular - in such
3096 //cases we don't need to recurse (empty scope is returned)
3097 return new CompoundScope(t.tsym);
3098 }
3099 try {
3100 seenTypes.add(t.tsym);
3101 ClassSymbol csym = (ClassSymbol)t.tsym;
3102 CompoundScope membersClosure = _map.get(csym);
3103 if (membersClosure == null) {
3104 membersClosure = new CompoundScope(csym);
3105 for (Type i : interfaces(t)) {
3106 membersClosure.prependSubScope(visit(i, null));
3107 }
3108 membersClosure.prependSubScope(visit(supertype(t), null));
3109 membersClosure.prependSubScope(csym.members());
3110 _map.put(csym, membersClosure);
3111 }
3112 return membersClosure;
3113 }
3114 finally {
3115 seenTypes.remove(t.tsym);
3116 }
3117 }
3118
3119 @Override
3120 public CompoundScope visitTypeVar(TypeVar t, Void _unused) {
3121 return visit(t.getUpperBound(), null);
3122 }
3123 }
3124
3125 private MembersClosureCache membersCache = new MembersClosureCache();
3126
3127 public CompoundScope membersClosure(Type site, boolean skipInterface) {
3128 CompoundScope cs = membersCache.visit(site, null);
3129 Assert.checkNonNull(cs, () -> "type " + site);
3130 return skipInterface ? membersCache.new MembersScope(cs) : cs;
3131 }
3132 // </editor-fold>
3133
3134
3135 /** Return first abstract member of class `sym'.
3136 */
3137 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) {
3138 try {
3139 return firstUnimplementedAbstractImpl(sym, sym);
3140 } catch (CompletionFailure ex) {
3141 chk.completionError(enter.getEnv(sym).tree.pos(), ex);
3142 return null;
3143 }
3144 }
3145 //where:
3146 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) {
3147 MethodSymbol undef = null;
3148 // Do not bother to search in classes that are not abstract,
3149 // since they cannot have abstract members.
3150 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
3151 Scope s = c.members();
3152 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
3153 if (sym.kind == MTH &&
3154 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
3155 MethodSymbol absmeth = (MethodSymbol)sym;
3156 MethodSymbol implmeth = absmeth.implementation(impl, this, true);
3157 if (implmeth == null || implmeth == absmeth) {
3158 //look for default implementations
3159 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head;
3160 if (prov != null && prov.overrides(absmeth, impl, this, true)) {
3161 implmeth = prov;
3162 }
3163 }
3164 if (implmeth == null || implmeth == absmeth) {
3165 undef = absmeth;
3166 break;
3167 }
3168 }
3169 }
3170 if (undef == null) {
3171 Type st = supertype(c.type);
3172 if (st.hasTag(CLASS))
3173 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym);
3174 }
3175 for (List<Type> l = interfaces(c.type);
3176 undef == null && l.nonEmpty();
3177 l = l.tail) {
3178 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym);
3179 }
3180 }
3181 return undef;
3182 }
3183
3184 public class CandidatesCache {
3185 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>();
3186
3187 class Entry {
3188 Type site;
3189 MethodSymbol msym;
3190
3191 Entry(Type site, MethodSymbol msym) {
3192 this.site = site;
3193 this.msym = msym;
3194 }
3195
3196 @Override
3197 public boolean equals(Object obj) {
3198 return (obj instanceof Entry entry)
3199 && entry.msym == msym
3200 && isSameType(site, entry.site);
3201 }
3202
3203 @Override
3204 public int hashCode() {
3205 return Types.this.hashCode(site) & ~msym.hashCode();
3206 }
3207 }
3208
3209 public List<MethodSymbol> get(Entry e) {
3210 return cache.get(e);
3211 }
3212
3213 public void put(Entry e, List<MethodSymbol> msymbols) {
3214 cache.put(e, msymbols);
3215 }
3216 }
3217
3218 public CandidatesCache candidatesCache = new CandidatesCache();
3219
3220 //where
3221 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
3222 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms);
3223 List<MethodSymbol> candidates = candidatesCache.get(e);
3224 if (candidates == null) {
3225 Predicate<Symbol> filter = new MethodFilter(ms, site);
3226 List<MethodSymbol> candidates2 = List.nil();
3227 for (Symbol s : membersClosure(site, false).getSymbols(filter)) {
3228 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
3229 return List.of((MethodSymbol)s);
3230 } else if (!candidates2.contains(s)) {
3231 candidates2 = candidates2.prepend((MethodSymbol)s);
3232 }
3233 }
3234 candidates = prune(candidates2);
3235 candidatesCache.put(e, candidates);
3236 }
3237 return candidates;
3238 }
3239
3240 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
3241 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>();
3242 for (MethodSymbol m1 : methods) {
3243 boolean isMin_m1 = true;
3244 for (MethodSymbol m2 : methods) {
3245 if (m1 == m2) continue;
3246 if (m2.owner != m1.owner &&
3247 asSuper(m2.owner.type, m1.owner) != null) {
3248 isMin_m1 = false;
3249 break;
3250 }
3251 }
3252 if (isMin_m1)
3253 methodsMin.append(m1);
3254 }
3255 return methodsMin.toList();
3256 }
3257 // where
3258 private class MethodFilter implements Predicate<Symbol> {
3259
3260 Symbol msym;
3261 Type site;
3262
3263 MethodFilter(Symbol msym, Type site) {
3264 this.msym = msym;
3265 this.site = site;
3266 }
3267
3268 @Override
3269 public boolean test(Symbol s) {
3270 return s.kind == MTH &&
3271 s.name == msym.name &&
3272 (s.flags() & SYNTHETIC) == 0 &&
3273 s.isInheritedIn(site.tsym, Types.this) &&
3274 overrideEquivalent(memberType(site, s), memberType(site, msym));
3275 }
3276 }
3277 // </editor-fold>
3278
3279 /**
3280 * Does t have the same arguments as s? It is assumed that both
3281 * types are (possibly polymorphic) method types. Monomorphic
3282 * method types "have the same arguments", if their argument lists
3283 * are equal. Polymorphic method types "have the same arguments",
3284 * if they have the same arguments after renaming all type
3285 * variables of one to corresponding type variables in the other,
3286 * where correspondence is by position in the type parameter list.
3287 */
3288 public boolean hasSameArgs(Type t, Type s) {
3289 return hasSameArgs(t, s, true);
3290 }
3291
3292 public boolean hasSameArgs(Type t, Type s, boolean strict) {
3293 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
3294 }
3295
3296 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
3297 return hasSameArgs.visit(t, s);
3298 }
3299 // where
3300 private class HasSameArgs extends TypeRelation {
3301
3302 boolean strict;
3303
3304 public HasSameArgs(boolean strict) {
3305 this.strict = strict;
3306 }
3307
3308 public Boolean visitType(Type t, Type s) {
3309 throw new AssertionError();
3310 }
3311
3312 @Override
3313 public Boolean visitMethodType(MethodType t, Type s) {
3314 return s.hasTag(METHOD)
3315 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
3316 }
3317
3318 @Override
3319 public Boolean visitForAll(ForAll t, Type s) {
3320 if (!s.hasTag(FORALL))
3321 return strict ? false : visitMethodType(t.asMethodType(), s);
3322
3323 ForAll forAll = (ForAll)s;
3324 return hasSameBounds(t, forAll)
3325 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
3326 }
3327
3328 @Override
3329 public Boolean visitErrorType(ErrorType t, Type s) {
3330 return false;
3331 }
3332 }
3333
3334 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
3335 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
3336
3337 // </editor-fold>
3338
3339 // <editor-fold defaultstate="collapsed" desc="subst">
3340 public List<Type> subst(List<Type> ts,
3341 List<Type> from,
3342 List<Type> to) {
3343 return ts.map(new Subst(from, to));
3344 }
3345
3346 /**
3347 * Substitute all occurrences of a type in `from' with the
3348 * corresponding type in `to' in 't'. Match lists `from' and `to'
3349 * from the right: If lists have different length, discard leading
3350 * elements of the longer list.
3351 */
3352 public Type subst(Type t, List<Type> from, List<Type> to) {
3353 return t.map(new Subst(from, to));
3354 }
3355
3356 /* this class won't substitute all types for example UndetVars are never substituted, this is
3357 * by design as UndetVars are used locally during inference and shouldn't escape from inference routines,
3358 * some specialized applications could need a tailored solution
3359 */
3360 private class Subst extends StructuralTypeMapping<Void> {
3361 List<Type> from;
3362 List<Type> to;
3363
3364 public Subst(List<Type> from, List<Type> to) {
3365 int fromLength = from.length();
3366 int toLength = to.length();
3367 while (fromLength > toLength) {
3368 fromLength--;
3369 from = from.tail;
3370 }
3371 while (fromLength < toLength) {
3372 toLength--;
3373 to = to.tail;
3374 }
3375 this.from = from;
3376 this.to = to;
3377 }
3378
3379 @Override
3380 public Type visitTypeVar(TypeVar t, Void ignored) {
3381 for (List<Type> from = this.from, to = this.to;
3382 from.nonEmpty();
3383 from = from.tail, to = to.tail) {
3384 if (t.equalsIgnoreMetadata(from.head)) {
3385 return to.head.withTypeVar(t);
3386 }
3387 }
3388 return t;
3389 }
3390
3391 @Override
3392 public Type visitClassType(ClassType t, Void ignored) {
3393 if (!t.isCompound()) {
3394 return super.visitClassType(t, ignored);
3395 } else {
3396 Type st = visit(supertype(t));
3397 List<Type> is = visit(interfaces(t), ignored);
3398 if (st == supertype(t) && is == interfaces(t))
3399 return t;
3400 else
3401 return makeIntersectionType(is.prepend(st));
3402 }
3403 }
3404
3405 @Override
3406 public Type visitWildcardType(WildcardType t, Void ignored) {
3407 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored);
3408 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) {
3409 t2.type = wildUpperBound(t2.type);
3410 }
3411 return t2;
3412 }
3413
3414 @Override
3415 public Type visitForAll(ForAll t, Void ignored) {
3416 if (Type.containsAny(to, t.tvars)) {
3417 //perform alpha-renaming of free-variables in 't'
3418 //if 'to' types contain variables that are free in 't'
3419 List<Type> freevars = newInstances(t.tvars);
3420 t = new ForAll(freevars,
3421 Types.this.subst(t.qtype, t.tvars, freevars));
3422 }
3423 List<Type> tvars1 = substBounds(t.tvars, from, to);
3424 Type qtype1 = visit(t.qtype);
3425 if (tvars1 == t.tvars && qtype1 == t.qtype) {
3426 return t;
3427 } else if (tvars1 == t.tvars) {
3428 return new ForAll(tvars1, qtype1) {
3429 @Override
3430 public boolean needsStripping() {
3431 return true;
3432 }
3433 };
3434 } else {
3435 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) {
3436 @Override
3437 public boolean needsStripping() {
3438 return true;
3439 }
3440 };
3441 }
3442 }
3443 }
3444
3445 public List<Type> substBounds(List<Type> tvars,
3446 List<Type> from,
3447 List<Type> to) {
3448 if (tvars.isEmpty())
3449 return tvars;
3450 ListBuffer<Type> newBoundsBuf = new ListBuffer<>();
3451 boolean changed = false;
3452 // calculate new bounds
3453 for (Type t : tvars) {
3454 TypeVar tv = (TypeVar) t;
3455 Type bound = subst(tv.getUpperBound(), from, to);
3456 if (bound != tv.getUpperBound())
3457 changed = true;
3458 newBoundsBuf.append(bound);
3459 }
3460 if (!changed)
3461 return tvars;
3462 ListBuffer<Type> newTvars = new ListBuffer<>();
3463 // create new type variables without bounds
3464 for (Type t : tvars) {
3465 newTvars.append(new TypeVar(t.tsym, null, syms.botType,
3466 t.getMetadata()));
3467 }
3468 // the new bounds should use the new type variables in place
3469 // of the old
3470 List<Type> newBounds = newBoundsBuf.toList();
3471 from = tvars;
3472 to = newTvars.toList();
3473 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
3474 newBounds.head = subst(newBounds.head, from, to);
3475 }
3476 newBounds = newBoundsBuf.toList();
3477 // set the bounds of new type variables to the new bounds
3478 for (Type t : newTvars.toList()) {
3479 TypeVar tv = (TypeVar) t;
3480 tv.setUpperBound( newBounds.head );
3481 newBounds = newBounds.tail;
3482 }
3483 return newTvars.toList();
3484 }
3485
3486 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
3487 Type bound1 = subst(t.getUpperBound(), from, to);
3488 if (bound1 == t.getUpperBound())
3489 return t;
3490 else {
3491 // create new type variable without bounds
3492 TypeVar tv = new TypeVar(t.tsym, null, syms.botType,
3493 t.getMetadata());
3494 // the new bound should use the new type variable in place
3495 // of the old
3496 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) );
3497 return tv;
3498 }
3499 }
3500 // </editor-fold>
3501
3502 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
3503 /**
3504 * Does t have the same bounds for quantified variables as s?
3505 */
3506 public boolean hasSameBounds(ForAll t, ForAll s) {
3507 List<Type> l1 = t.tvars;
3508 List<Type> l2 = s.tvars;
3509 while (l1.nonEmpty() && l2.nonEmpty() &&
3510 isSameType(l1.head.getUpperBound(),
3511 subst(l2.head.getUpperBound(),
3512 s.tvars,
3513 t.tvars))) {
3514 l1 = l1.tail;
3515 l2 = l2.tail;
3516 }
3517 return l1.isEmpty() && l2.isEmpty();
3518 }
3519 // </editor-fold>
3520
3521 // <editor-fold defaultstate="collapsed" desc="newInstances">
3522 /** Create new vector of type variables from list of variables
3523 * changing all recursive bounds from old to new list.
3524 */
3525 public List<Type> newInstances(List<Type> tvars) {
3526 List<Type> tvars1 = tvars.map(newInstanceFun);
3527 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
3528 TypeVar tv = (TypeVar) l.head;
3529 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) );
3530 }
3531 return tvars1;
3532 }
3533 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() {
3534 @Override
3535 public TypeVar visitTypeVar(TypeVar t, Void _unused) {
3536 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata());
3537 }
3538 };
3539 // </editor-fold>
3540
3541 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
3542 return original.accept(methodWithParameters, newParams);
3543 }
3544 // where
3545 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
3546 public Type visitType(Type t, List<Type> newParams) {
3547 throw new IllegalArgumentException("Not a method type: " + t);
3548 }
3549 public Type visitMethodType(MethodType t, List<Type> newParams) {
3550 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
3551 }
3552 public Type visitForAll(ForAll t, List<Type> newParams) {
3553 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
3554 }
3555 };
3556
3557 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
3558 return original.accept(methodWithThrown, newThrown);
3559 }
3560 // where
3561 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
3562 public Type visitType(Type t, List<Type> newThrown) {
3563 throw new IllegalArgumentException("Not a method type: " + t);
3564 }
3565 public Type visitMethodType(MethodType t, List<Type> newThrown) {
3566 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
3567 }
3568 public Type visitForAll(ForAll t, List<Type> newThrown) {
3569 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
3570 }
3571 };
3572
3573 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
3574 return original.accept(methodWithReturn, newReturn);
3575 }
3576 // where
3577 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
3578 public Type visitType(Type t, Type newReturn) {
3579 throw new IllegalArgumentException("Not a method type: " + t);
3580 }
3581 public Type visitMethodType(MethodType t, Type newReturn) {
3582 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) {
3583 @Override
3584 public Type baseType() {
3585 return t;
3586 }
3587 };
3588 }
3589 public Type visitForAll(ForAll t, Type newReturn) {
3590 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) {
3591 @Override
3592 public Type baseType() {
3593 return t;
3594 }
3595 };
3596 }
3597 };
3598
3599 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3600 public Type createErrorType(Type originalType) {
3601 return new ErrorType(originalType, syms.errSymbol);
3602 }
3603
3604 public Type createErrorType(ClassSymbol c, Type originalType) {
3605 return new ErrorType(c, originalType);
3606 }
3607
3608 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3609 return new ErrorType(name, container, originalType);
3610 }
3611 // </editor-fold>
3612
3613 // <editor-fold defaultstate="collapsed" desc="rank">
3614 /**
3615 * The rank of a class is the length of the longest path between
3616 * the class and java.lang.Object in the class inheritance
3617 * graph. Undefined for all but reference types.
3618 */
3619 public int rank(Type t) {
3620 switch(t.getTag()) {
3621 case CLASS: {
3622 ClassType cls = (ClassType)t;
3623 if (cls.rank_field < 0) {
3624 Name fullname = cls.tsym.getQualifiedName();
3625 if (fullname == names.java_lang_Object)
3626 cls.rank_field = 0;
3627 else {
3628 int r = rank(supertype(cls));
3629 for (List<Type> l = interfaces(cls);
3630 l.nonEmpty();
3631 l = l.tail) {
3632 if (rank(l.head) > r)
3633 r = rank(l.head);
3634 }
3635 cls.rank_field = r + 1;
3636 }
3637 }
3638 return cls.rank_field;
3639 }
3640 case TYPEVAR: {
3641 TypeVar tvar = (TypeVar)t;
3642 if (tvar.rank_field < 0) {
3643 int r = rank(supertype(tvar));
3644 for (List<Type> l = interfaces(tvar);
3645 l.nonEmpty();
3646 l = l.tail) {
3647 if (rank(l.head) > r) r = rank(l.head);
3648 }
3649 tvar.rank_field = r + 1;
3650 }
3651 return tvar.rank_field;
3652 }
3653 case ERROR:
3654 case NONE:
3655 return 0;
3656 default:
3657 throw new AssertionError();
3658 }
3659 }
3660 // </editor-fold>
3661
3662 /**
3663 * Helper method for generating a string representation of a given type
3664 * accordingly to a given locale
3665 */
3666 public String toString(Type t, Locale locale) {
3667 return Printer.createStandardPrinter(messages).visit(t, locale);
3668 }
3669
3670 /**
3671 * Helper method for generating a string representation of a given type
3672 * accordingly to a given locale
3673 */
3674 public String toString(Symbol t, Locale locale) {
3675 return Printer.createStandardPrinter(messages).visit(t, locale);
3676 }
3677
3678 // <editor-fold defaultstate="collapsed" desc="toString">
3679 /**
3680 * This toString is slightly more descriptive than the one on Type.
3681 *
3682 * @deprecated Types.toString(Type t, Locale l) provides better support
3683 * for localization
3684 */
3685 @Deprecated
3686 public String toString(Type t) {
3687 if (t.hasTag(FORALL)) {
3688 ForAll forAll = (ForAll)t;
3689 return typaramsString(forAll.tvars) + forAll.qtype;
3690 }
3691 return "" + t;
3692 }
3693 // where
3694 private String typaramsString(List<Type> tvars) {
3695 StringBuilder s = new StringBuilder();
3696 s.append('<');
3697 boolean first = true;
3698 for (Type t : tvars) {
3699 if (!first) s.append(", ");
3700 first = false;
3701 appendTyparamString(((TypeVar)t), s);
3702 }
3703 s.append('>');
3704 return s.toString();
3705 }
3706 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3707 buf.append(t);
3708 if (t.getUpperBound() == null ||
3709 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object)
3710 return;
3711 buf.append(" extends "); // Java syntax; no need for i18n
3712 Type bound = t.getUpperBound();
3713 if (!bound.isCompound()) {
3714 buf.append(bound);
3715 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3716 buf.append(supertype(t));
3717 for (Type intf : interfaces(t)) {
3718 buf.append('&');
3719 buf.append(intf);
3720 }
3721 } else {
3722 // No superclass was given in bounds.
3723 // In this case, supertype is Object, erasure is first interface.
3724 boolean first = true;
3725 for (Type intf : interfaces(t)) {
3726 if (!first) buf.append('&');
3727 first = false;
3728 buf.append(intf);
3729 }
3730 }
3731 }
3732 // </editor-fold>
3733
3734 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3735 /**
3736 * A cache for closures.
3737 *
3738 * <p>A closure is a list of all the supertypes and interfaces of
3739 * a class or interface type, ordered by ClassSymbol.precedes
3740 * (that is, subclasses come first, arbitrarily but fixed
3741 * otherwise).
3742 */
3743 private Map<Type,List<Type>> closureCache = new HashMap<>();
3744
3745 /**
3746 * Returns the closure of a class or interface type.
3747 */
3748 public List<Type> closure(Type t) {
3749 List<Type> cl = closureCache.get(t);
3750 if (cl == null) {
3751 Type st = supertype(t);
3752 if (!t.isCompound()) {
3753 if (st.hasTag(CLASS)) {
3754 cl = insert(closure(st), t);
3755 } else if (st.hasTag(TYPEVAR)) {
3756 cl = closure(st).prepend(t);
3757 } else {
3758 cl = List.of(t);
3759 }
3760 } else {
3761 cl = closure(supertype(t));
3762 }
3763 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3764 cl = union(cl, closure(l.head));
3765 closureCache.put(t, cl);
3766 }
3767 return cl;
3768 }
3769
3770 /**
3771 * Collect types into a new closure (using a {@code ClosureHolder})
3772 */
3773 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3774 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip),
3775 ClosureHolder::add,
3776 ClosureHolder::merge,
3777 ClosureHolder::closure);
3778 }
3779 //where
3780 class ClosureHolder {
3781 List<Type> closure;
3782 final boolean minClosure;
3783 final BiPredicate<Type, Type> shouldSkip;
3784
3785 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3786 this.closure = List.nil();
3787 this.minClosure = minClosure;
3788 this.shouldSkip = shouldSkip;
3789 }
3790
3791 void add(Type type) {
3792 closure = insert(closure, type, shouldSkip);
3793 }
3794
3795 ClosureHolder merge(ClosureHolder other) {
3796 closure = union(closure, other.closure, shouldSkip);
3797 return this;
3798 }
3799
3800 List<Type> closure() {
3801 return minClosure ? closureMin(closure) : closure;
3802 }
3803 }
3804
3805 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym;
3806
3807 /**
3808 * Insert a type in a closure
3809 */
3810 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) {
3811 if (cl.isEmpty()) {
3812 return cl.prepend(t);
3813 } else if (shouldSkip.test(t, cl.head)) {
3814 return cl;
3815 } else if (t.tsym.precedes(cl.head.tsym, this)) {
3816 return cl.prepend(t);
3817 } else {
3818 // t comes after head, or the two are unrelated
3819 return insert(cl.tail, t, shouldSkip).prepend(cl.head);
3820 }
3821 }
3822
3823 public List<Type> insert(List<Type> cl, Type t) {
3824 return insert(cl, t, basicClosureSkip);
3825 }
3826
3827 /**
3828 * Form the union of two closures
3829 */
3830 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) {
3831 if (cl1.isEmpty()) {
3832 return cl2;
3833 } else if (cl2.isEmpty()) {
3834 return cl1;
3835 } else if (shouldSkip.test(cl1.head, cl2.head)) {
3836 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
3837 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3838 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
3839 } else {
3840 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
3841 }
3842 }
3843
3844 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3845 return union(cl1, cl2, basicClosureSkip);
3846 }
3847
3848 /**
3849 * Intersect two closures
3850 */
3851 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3852 if (cl1 == cl2)
3853 return cl1;
3854 if (cl1.isEmpty() || cl2.isEmpty())
3855 return List.nil();
3856 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3857 return intersect(cl1.tail, cl2);
3858 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3859 return intersect(cl1, cl2.tail);
3860 if (isSameType(cl1.head, cl2.head))
3861 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3862 if (cl1.head.tsym == cl2.head.tsym &&
3863 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) {
3864 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3865 Type merge = merge(cl1.head,cl2.head);
3866 return intersect(cl1.tail, cl2.tail).prepend(merge);
3867 }
3868 if (cl1.head.isRaw() || cl2.head.isRaw())
3869 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3870 }
3871 return intersect(cl1.tail, cl2.tail);
3872 }
3873 // where
3874 class TypePair {
3875 final Type t1;
3876 final Type t2;;
3877
3878 TypePair(Type t1, Type t2) {
3879 this.t1 = t1;
3880 this.t2 = t2;
3881 }
3882 @Override
3883 public int hashCode() {
3884 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3885 }
3886 @Override
3887 public boolean equals(Object obj) {
3888 return (obj instanceof TypePair typePair)
3889 && isSameType(t1, typePair.t1)
3890 && isSameType(t2, typePair.t2);
3891 }
3892 }
3893 Set<TypePair> mergeCache = new HashSet<>();
3894 private Type merge(Type c1, Type c2) {
3895 ClassType class1 = (ClassType) c1;
3896 List<Type> act1 = class1.getTypeArguments();
3897 ClassType class2 = (ClassType) c2;
3898 List<Type> act2 = class2.getTypeArguments();
3899 ListBuffer<Type> merged = new ListBuffer<>();
3900 List<Type> typarams = class1.tsym.type.getTypeArguments();
3901
3902 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3903 if (containsType(act1.head, act2.head)) {
3904 merged.append(act1.head);
3905 } else if (containsType(act2.head, act1.head)) {
3906 merged.append(act2.head);
3907 } else {
3908 TypePair pair = new TypePair(c1, c2);
3909 Type m;
3910 if (mergeCache.add(pair)) {
3911 m = new WildcardType(lub(wildUpperBound(act1.head),
3912 wildUpperBound(act2.head)),
3913 BoundKind.EXTENDS,
3914 syms.boundClass);
3915 mergeCache.remove(pair);
3916 } else {
3917 m = new WildcardType(syms.objectType,
3918 BoundKind.UNBOUND,
3919 syms.boundClass);
3920 }
3921 merged.append(m.withTypeVar(typarams.head));
3922 }
3923 act1 = act1.tail;
3924 act2 = act2.tail;
3925 typarams = typarams.tail;
3926 }
3927 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3928 // There is no spec detailing how type annotations are to
3929 // be inherited. So set it to noAnnotations for now
3930 return new ClassType(class1.getEnclosingType(), merged.toList(),
3931 class1.tsym, List.nil());
3932 }
3933
3934 /**
3935 * Return the minimum type of a closure, a compound type if no
3936 * unique minimum exists.
3937 */
3938 private Type compoundMin(List<Type> cl) {
3939 if (cl.isEmpty()) return syms.objectType;
3940 List<Type> compound = closureMin(cl);
3941 if (compound.isEmpty())
3942 return null;
3943 else if (compound.tail.isEmpty())
3944 return compound.head;
3945 else
3946 return makeIntersectionType(compound);
3947 }
3948
3949 /**
3950 * Return the minimum types of a closure, suitable for computing
3951 * compoundMin or glb.
3952 */
3953 private List<Type> closureMin(List<Type> cl) {
3954 ListBuffer<Type> classes = new ListBuffer<>();
3955 ListBuffer<Type> interfaces = new ListBuffer<>();
3956 Set<Type> toSkip = new HashSet<>();
3957 while (!cl.isEmpty()) {
3958 Type current = cl.head;
3959 boolean keep = !toSkip.contains(current);
3960 if (keep && current.hasTag(TYPEVAR)) {
3961 // skip lower-bounded variables with a subtype in cl.tail
3962 for (Type t : cl.tail) {
3963 if (isSubtypeNoCapture(t, current)) {
3964 keep = false;
3965 break;
3966 }
3967 }
3968 }
3969 if (keep) {
3970 if (current.isInterface())
3971 interfaces.append(current);
3972 else
3973 classes.append(current);
3974 for (Type t : cl.tail) {
3975 // skip supertypes of 'current' in cl.tail
3976 if (isSubtypeNoCapture(current, t))
3977 toSkip.add(t);
3978 }
3979 }
3980 cl = cl.tail;
3981 }
3982 return classes.appendList(interfaces).toList();
3983 }
3984
3985 /**
3986 * Return the least upper bound of list of types. if the lub does
3987 * not exist return null.
3988 */
3989 public Type lub(List<Type> ts) {
3990 return lub(ts.toArray(new Type[ts.length()]));
3991 }
3992
3993 /**
3994 * Return the least upper bound (lub) of set of types. If the lub
3995 * does not exist return the type of null (bottom).
3996 */
3997 public Type lub(Type... ts) {
3998 final int UNKNOWN_BOUND = 0;
3999 final int ARRAY_BOUND = 1;
4000 final int CLASS_BOUND = 2;
4001
4002 int[] kinds = new int[ts.length];
4003
4004 int boundkind = UNKNOWN_BOUND;
4005 for (int i = 0 ; i < ts.length ; i++) {
4006 Type t = ts[i];
4007 switch (t.getTag()) {
4008 case CLASS:
4009 boundkind |= kinds[i] = CLASS_BOUND;
4010 break;
4011 case ARRAY:
4012 boundkind |= kinds[i] = ARRAY_BOUND;
4013 break;
4014 case TYPEVAR:
4015 do {
4016 t = t.getUpperBound();
4017 } while (t.hasTag(TYPEVAR));
4018 if (t.hasTag(ARRAY)) {
4019 boundkind |= kinds[i] = ARRAY_BOUND;
4020 } else {
4021 boundkind |= kinds[i] = CLASS_BOUND;
4022 }
4023 break;
4024 default:
4025 kinds[i] = UNKNOWN_BOUND;
4026 if (t.isPrimitive())
4027 return syms.errType;
4028 }
4029 }
4030 switch (boundkind) {
4031 case 0:
4032 return syms.botType;
4033
4034 case ARRAY_BOUND:
4035 // calculate lub(A[], B[])
4036 Type[] elements = new Type[ts.length];
4037 for (int i = 0 ; i < ts.length ; i++) {
4038 Type elem = elements[i] = elemTypeFun.apply(ts[i]);
4039 if (elem.isPrimitive()) {
4040 // if a primitive type is found, then return
4041 // arraySuperType unless all the types are the
4042 // same
4043 Type first = ts[0];
4044 for (int j = 1 ; j < ts.length ; j++) {
4045 if (!isSameType(first, ts[j])) {
4046 // lub(int[], B[]) is Cloneable & Serializable
4047 return arraySuperType();
4048 }
4049 }
4050 // all the array types are the same, return one
4051 // lub(int[], int[]) is int[]
4052 return first;
4053 }
4054 }
4055 // lub(A[], B[]) is lub(A, B)[]
4056 return new ArrayType(lub(elements), syms.arrayClass);
4057
4058 case CLASS_BOUND:
4059 // calculate lub(A, B)
4060 int startIdx = 0;
4061 for (int i = 0; i < ts.length ; i++) {
4062 Type t = ts[i];
4063 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) {
4064 break;
4065 } else {
4066 startIdx++;
4067 }
4068 }
4069 Assert.check(startIdx < ts.length);
4070 //step 1 - compute erased candidate set (EC)
4071 List<Type> cl = erasedSupertypes(ts[startIdx]);
4072 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4073 Type t = ts[i];
4074 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
4075 cl = intersect(cl, erasedSupertypes(t));
4076 }
4077 //step 2 - compute minimal erased candidate set (MEC)
4078 List<Type> mec = closureMin(cl);
4079 //step 3 - for each element G in MEC, compute lci(Inv(G))
4080 List<Type> candidates = List.nil();
4081 for (Type erasedSupertype : mec) {
4082 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
4083 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4084 Type superType = asSuper(ts[i], erasedSupertype.tsym);
4085 lci = intersect(lci, superType != null ? List.of(superType) : List.nil());
4086 }
4087 candidates = candidates.appendList(lci);
4088 }
4089 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
4090 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
4091 return compoundMin(candidates);
4092
4093 default:
4094 // calculate lub(A, B[])
4095 List<Type> classes = List.of(arraySuperType());
4096 for (int i = 0 ; i < ts.length ; i++) {
4097 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays
4098 classes = classes.prepend(ts[i]);
4099 }
4100 // lub(A, B[]) is lub(A, arraySuperType)
4101 return lub(classes);
4102 }
4103 }
4104 // where
4105 List<Type> erasedSupertypes(Type t) {
4106 ListBuffer<Type> buf = new ListBuffer<>();
4107 for (Type sup : closure(t)) {
4108 if (sup.hasTag(TYPEVAR)) {
4109 buf.append(sup);
4110 } else {
4111 buf.append(erasure(sup));
4112 }
4113 }
4114 return buf.toList();
4115 }
4116
4117 private Type arraySuperType;
4118 private Type arraySuperType() {
4119 // initialized lazily to avoid problems during compiler startup
4120 if (arraySuperType == null) {
4121 // JLS 10.8: all arrays implement Cloneable and Serializable.
4122 arraySuperType = makeIntersectionType(List.of(syms.serializableType,
4123 syms.cloneableType), true);
4124 }
4125 return arraySuperType;
4126 }
4127 // </editor-fold>
4128
4129 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
4130 public Type glb(List<Type> ts) {
4131 Type t1 = ts.head;
4132 for (Type t2 : ts.tail) {
4133 if (t1.isErroneous())
4134 return t1;
4135 t1 = glb(t1, t2);
4136 }
4137 return t1;
4138 }
4139 //where
4140 public Type glb(Type t, Type s) {
4141 if (s == null)
4142 return t;
4143 else if (t.isPrimitive() || s.isPrimitive())
4144 return syms.errType;
4145 else if (isSubtypeNoCapture(t, s))
4146 return t;
4147 else if (isSubtypeNoCapture(s, t))
4148 return s;
4149
4150 List<Type> closure = union(closure(t), closure(s));
4151 return glbFlattened(closure, t);
4152 }
4153 //where
4154 /**
4155 * Perform glb for a list of non-primitive, non-error, non-compound types;
4156 * redundant elements are removed. Bounds should be ordered according to
4157 * {@link Symbol#precedes(TypeSymbol,Types)}.
4158 *
4159 * @param flatBounds List of type to glb
4160 * @param errT Original type to use if the result is an error type
4161 */
4162 private Type glbFlattened(List<Type> flatBounds, Type errT) {
4163 List<Type> bounds = closureMin(flatBounds);
4164
4165 if (bounds.isEmpty()) { // length == 0
4166 return syms.objectType;
4167 } else if (bounds.tail.isEmpty()) { // length == 1
4168 return bounds.head;
4169 } else { // length > 1
4170 int classCount = 0;
4171 List<Type> cvars = List.nil();
4172 List<Type> lowers = List.nil();
4173 for (Type bound : bounds) {
4174 if (!bound.isInterface()) {
4175 classCount++;
4176 Type lower = cvarLowerBound(bound);
4177 if (bound != lower && !lower.hasTag(BOT)) {
4178 cvars = cvars.append(bound);
4179 lowers = lowers.append(lower);
4180 }
4181 }
4182 }
4183 if (classCount > 1) {
4184 if (lowers.isEmpty()) {
4185 return createErrorType(errT);
4186 } else {
4187 // try again with lower bounds included instead of capture variables
4188 List<Type> newBounds = bounds.diff(cvars).appendList(lowers);
4189 return glb(newBounds);
4190 }
4191 }
4192 }
4193 return makeIntersectionType(bounds);
4194 }
4195 // </editor-fold>
4196
4197 // <editor-fold defaultstate="collapsed" desc="hashCode">
4198 /**
4199 * Compute a hash code on a type.
4200 */
4201 public int hashCode(Type t) {
4202 return hashCode(t, false);
4203 }
4204
4205 public int hashCode(Type t, boolean strict) {
4206 return strict ?
4207 hashCodeStrictVisitor.visit(t) :
4208 hashCodeVisitor.visit(t);
4209 }
4210 // where
4211 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor();
4212 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() {
4213 @Override
4214 public Integer visitTypeVar(TypeVar t, Void ignored) {
4215 return System.identityHashCode(t);
4216 }
4217 };
4218
4219 private static class HashCodeVisitor extends UnaryVisitor<Integer> {
4220 public Integer visitType(Type t, Void ignored) {
4221 return t.getTag().ordinal();
4222 }
4223
4224 @Override
4225 public Integer visitClassType(ClassType t, Void ignored) {
4226 int result = visit(t.getEnclosingType());
4227 result *= 127;
4228 result += t.tsym.flatName().hashCode();
4229 for (Type s : t.getTypeArguments()) {
4230 result *= 127;
4231 result += visit(s);
4232 }
4233 return result;
4234 }
4235
4236 @Override
4237 public Integer visitMethodType(MethodType t, Void ignored) {
4238 int h = METHOD.ordinal();
4239 for (List<Type> thisargs = t.argtypes;
4240 thisargs.tail != null;
4241 thisargs = thisargs.tail)
4242 h = (h << 5) + visit(thisargs.head);
4243 return (h << 5) + visit(t.restype);
4244 }
4245
4246 @Override
4247 public Integer visitWildcardType(WildcardType t, Void ignored) {
4248 int result = t.kind.hashCode();
4249 if (t.type != null) {
4250 result *= 127;
4251 result += visit(t.type);
4252 }
4253 return result;
4254 }
4255
4256 @Override
4257 public Integer visitArrayType(ArrayType t, Void ignored) {
4258 return visit(t.elemtype) + 12;
4259 }
4260
4261 @Override
4262 public Integer visitTypeVar(TypeVar t, Void ignored) {
4263 return System.identityHashCode(t);
4264 }
4265
4266 @Override
4267 public Integer visitUndetVar(UndetVar t, Void ignored) {
4268 return System.identityHashCode(t);
4269 }
4270
4271 @Override
4272 public Integer visitErrorType(ErrorType t, Void ignored) {
4273 return 0;
4274 }
4275 }
4276 // </editor-fold>
4277
4278 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
4279 /**
4280 * Does t have a result that is a subtype of the result type of s,
4281 * suitable for covariant returns? It is assumed that both types
4282 * are (possibly polymorphic) method types. Monomorphic method
4283 * types are handled in the obvious way. Polymorphic method types
4284 * require renaming all type variables of one to corresponding
4285 * type variables in the other, where correspondence is by
4286 * position in the type parameter list. */
4287 public boolean resultSubtype(Type t, Type s, Warner warner) {
4288 List<Type> tvars = t.getTypeArguments();
4289 List<Type> svars = s.getTypeArguments();
4290 Type tres = t.getReturnType();
4291 Type sres = subst(s.getReturnType(), svars, tvars);
4292 return covariantReturnType(tres, sres, warner);
4293 }
4294
4295 /**
4296 * Return-Type-Substitutable.
4297 * @jls 8.4.5 Method Result
4298 */
4299 public boolean returnTypeSubstitutable(Type r1, Type r2) {
4300 if (hasSameArgs(r1, r2))
4301 return resultSubtype(r1, r2, noWarnings);
4302 else
4303 return covariantReturnType(r1.getReturnType(),
4304 erasure(r2.getReturnType()),
4305 noWarnings);
4306 }
4307
4308 public boolean returnTypeSubstitutable(Type r1,
4309 Type r2, Type r2res,
4310 Warner warner) {
4311 if (isSameType(r1.getReturnType(), r2res))
4312 return true;
4313 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
4314 return false;
4315
4316 if (hasSameArgs(r1, r2))
4317 return covariantReturnType(r1.getReturnType(), r2res, warner);
4318 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
4319 return true;
4320 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
4321 return false;
4322 warner.warn(LintCategory.UNCHECKED);
4323 return true;
4324 }
4325
4326 /**
4327 * Is t an appropriate return type in an overrider for a
4328 * method that returns s?
4329 */
4330 public boolean covariantReturnType(Type t, Type s, Warner warner) {
4331 return
4332 isSameType(t, s) ||
4333 !t.isPrimitive() &&
4334 !s.isPrimitive() &&
4335 isAssignable(t, s, warner);
4336 }
4337 // </editor-fold>
4338
4339 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
4340 /**
4341 * Return the class that boxes the given primitive.
4342 */
4343 public ClassSymbol boxedClass(Type t) {
4344 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]);
4345 }
4346
4347 /**
4348 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
4349 */
4350 public Type boxedTypeOrType(Type t) {
4351 return t.isPrimitive() ?
4352 boxedClass(t).type :
4353 t;
4354 }
4355
4356 /**
4357 * Return the primitive type corresponding to a boxed type.
4358 */
4359 public Type unboxedType(Type t) {
4360 if (t.hasTag(ERROR))
4361 return Type.noType;
4362 for (int i=0; i<syms.boxedName.length; i++) {
4363 Name box = syms.boxedName[i];
4364 if (box != null &&
4365 asSuper(t, syms.enterClass(syms.java_base, box)) != null)
4366 return syms.typeOfTag[i];
4367 }
4368 return Type.noType;
4369 }
4370
4371 /**
4372 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
4373 */
4374 public Type unboxedTypeOrType(Type t) {
4375 Type unboxedType = unboxedType(t);
4376 return unboxedType.hasTag(NONE) ? t : unboxedType;
4377 }
4378 // </editor-fold>
4379
4380 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
4381 /*
4382 * JLS 5.1.10 Capture Conversion:
4383 *
4384 * Let G name a generic type declaration with n formal type
4385 * parameters A1 ... An with corresponding bounds U1 ... Un. There
4386 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
4387 * where, for 1 <= i <= n:
4388 *
4389 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
4390 * Si is a fresh type variable whose upper bound is
4391 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
4392 * type.
4393 *
4394 * + If Ti is a wildcard type argument of the form ? extends Bi,
4395 * then Si is a fresh type variable whose upper bound is
4396 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
4397 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
4398 * a compile-time error if for any two classes (not interfaces)
4399 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
4400 *
4401 * + If Ti is a wildcard type argument of the form ? super Bi,
4402 * then Si is a fresh type variable whose upper bound is
4403 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
4404 *
4405 * + Otherwise, Si = Ti.
4406 *
4407 * Capture conversion on any type other than a parameterized type
4408 * (4.5) acts as an identity conversion (5.1.1). Capture
4409 * conversions never require a special action at run time and
4410 * therefore never throw an exception at run time.
4411 *
4412 * Capture conversion is not applied recursively.
4413 */
4414 /**
4415 * Capture conversion as specified by the JLS.
4416 */
4417
4418 public List<Type> capture(List<Type> ts) {
4419 List<Type> buf = List.nil();
4420 for (Type t : ts) {
4421 buf = buf.prepend(capture(t));
4422 }
4423 return buf.reverse();
4424 }
4425
4426 public Type capture(Type t) {
4427 if (!t.hasTag(CLASS)) {
4428 return t;
4429 }
4430 if (t.getEnclosingType() != Type.noType) {
4431 Type capturedEncl = capture(t.getEnclosingType());
4432 if (capturedEncl != t.getEnclosingType()) {
4433 Type type1 = memberType(capturedEncl, t.tsym);
4434 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
4435 }
4436 }
4437 ClassType cls = (ClassType)t;
4438 if (cls.isRaw() || !cls.isParameterized())
4439 return cls;
4440
4441 ClassType G = (ClassType)cls.asElement().asType();
4442 List<Type> A = G.getTypeArguments();
4443 List<Type> T = cls.getTypeArguments();
4444 List<Type> S = freshTypeVariables(T);
4445
4446 List<Type> currentA = A;
4447 List<Type> currentT = T;
4448 List<Type> currentS = S;
4449 boolean captured = false;
4450 while (!currentA.isEmpty() &&
4451 !currentT.isEmpty() &&
4452 !currentS.isEmpty()) {
4453 if (currentS.head != currentT.head) {
4454 captured = true;
4455 WildcardType Ti = (WildcardType)currentT.head;
4456 Type Ui = currentA.head.getUpperBound();
4457 CapturedType Si = (CapturedType)currentS.head;
4458 if (Ui == null)
4459 Ui = syms.objectType;
4460 switch (Ti.kind) {
4461 case UNBOUND:
4462 Si.setUpperBound( subst(Ui, A, S) );
4463 Si.lower = syms.botType;
4464 break;
4465 case EXTENDS:
4466 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) );
4467 Si.lower = syms.botType;
4468 break;
4469 case SUPER:
4470 Si.setUpperBound( subst(Ui, A, S) );
4471 Si.lower = Ti.getSuperBound();
4472 break;
4473 }
4474 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound();
4475 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower;
4476 if (!Si.getUpperBound().hasTag(ERROR) &&
4477 !Si.lower.hasTag(ERROR) &&
4478 isSameType(tmpBound, tmpLower)) {
4479 currentS.head = Si.getUpperBound();
4480 }
4481 }
4482 currentA = currentA.tail;
4483 currentT = currentT.tail;
4484 currentS = currentS.tail;
4485 }
4486 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
4487 return erasure(t); // some "rare" type involved
4488
4489 if (captured)
4490 return new ClassType(cls.getEnclosingType(), S, cls.tsym,
4491 cls.getMetadata());
4492 else
4493 return t;
4494 }
4495 // where
4496 public List<Type> freshTypeVariables(List<Type> types) {
4497 ListBuffer<Type> result = new ListBuffer<>();
4498 for (Type t : types) {
4499 if (t.hasTag(WILDCARD)) {
4500 Type bound = ((WildcardType)t).getExtendsBound();
4501 if (bound == null)
4502 bound = syms.objectType;
4503 result.append(new CapturedType(capturedName,
4504 syms.noSymbol,
4505 bound,
4506 syms.botType,
4507 (WildcardType)t));
4508 } else {
4509 result.append(t);
4510 }
4511 }
4512 return result.toList();
4513 }
4514 // </editor-fold>
4515
4516 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
4517 private boolean sideCast(Type from, Type to, Warner warn) {
4518 // We are casting from type $from$ to type $to$, which are
4519 // non-final unrelated types. This method
4520 // tries to reject a cast by transferring type parameters
4521 // from $to$ to $from$ by common superinterfaces.
4522 boolean reverse = false;
4523 Type target = to;
4524 if ((to.tsym.flags() & INTERFACE) == 0) {
4525 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4526 reverse = true;
4527 to = from;
4528 from = target;
4529 }
4530 List<Type> commonSupers = superClosure(to, erasure(from));
4531 boolean giveWarning = commonSupers.isEmpty();
4532 // The arguments to the supers could be unified here to
4533 // get a more accurate analysis
4534 while (commonSupers.nonEmpty()) {
4535 Type t1 = asSuper(from, commonSupers.head.tsym);
4536 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
4537 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4538 return false;
4539 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
4540 commonSupers = commonSupers.tail;
4541 }
4542 if (giveWarning && !isReifiable(reverse ? from : to))
4543 warn.warn(LintCategory.UNCHECKED);
4544 return true;
4545 }
4546
4547 private boolean sideCastFinal(Type from, Type to, Warner warn) {
4548 // We are casting from type $from$ to type $to$, which are
4549 // unrelated types one of which is final and the other of
4550 // which is an interface. This method
4551 // tries to reject a cast by transferring type parameters
4552 // from the final class to the interface.
4553 boolean reverse = false;
4554 Type target = to;
4555 if ((to.tsym.flags() & INTERFACE) == 0) {
4556 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4557 reverse = true;
4558 to = from;
4559 from = target;
4560 }
4561 Assert.check((from.tsym.flags() & FINAL) != 0);
4562 Type t1 = asSuper(from, to.tsym);
4563 if (t1 == null) return false;
4564 Type t2 = to;
4565 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4566 return false;
4567 if (!isReifiable(target) &&
4568 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
4569 warn.warn(LintCategory.UNCHECKED);
4570 return true;
4571 }
4572
4573 private boolean giveWarning(Type from, Type to) {
4574 List<Type> bounds = to.isCompound() ?
4575 directSupertypes(to) : List.of(to);
4576 for (Type b : bounds) {
4577 Type subFrom = asSub(from, b.tsym);
4578 if (b.isParameterized() &&
4579 (!(isUnbounded(b) ||
4580 isSubtype(from, b) ||
4581 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
4582 return true;
4583 }
4584 }
4585 return false;
4586 }
4587
4588 private List<Type> superClosure(Type t, Type s) {
4589 List<Type> cl = List.nil();
4590 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
4591 if (isSubtype(s, erasure(l.head))) {
4592 cl = insert(cl, l.head);
4593 } else {
4594 cl = union(cl, superClosure(l.head, s));
4595 }
4596 }
4597 return cl;
4598 }
4599
4600 private boolean containsTypeEquivalent(Type t, Type s) {
4601 return isSameType(t, s) || // shortcut
4602 containsType(t, s) && containsType(s, t);
4603 }
4604
4605 // <editor-fold defaultstate="collapsed" desc="adapt">
4606 /**
4607 * Adapt a type by computing a substitution which maps a source
4608 * type to a target type.
4609 *
4610 * @param source the source type
4611 * @param target the target type
4612 * @param from the type variables of the computed substitution
4613 * @param to the types of the computed substitution.
4614 */
4615 public void adapt(Type source,
4616 Type target,
4617 ListBuffer<Type> from,
4618 ListBuffer<Type> to) throws AdaptFailure {
4619 new Adapter(from, to).adapt(source, target);
4620 }
4621
4622 class Adapter extends SimpleVisitor<Void, Type> {
4623
4624 ListBuffer<Type> from;
4625 ListBuffer<Type> to;
4626 Map<Symbol,Type> mapping;
4627
4628 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
4629 this.from = from;
4630 this.to = to;
4631 mapping = new HashMap<>();
4632 }
4633
4634 public void adapt(Type source, Type target) throws AdaptFailure {
4635 visit(source, target);
4636 List<Type> fromList = from.toList();
4637 List<Type> toList = to.toList();
4638 while (!fromList.isEmpty()) {
4639 Type val = mapping.get(fromList.head.tsym);
4640 if (toList.head != val)
4641 toList.head = val;
4642 fromList = fromList.tail;
4643 toList = toList.tail;
4644 }
4645 }
4646
4647 @Override
4648 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
4649 if (target.hasTag(CLASS))
4650 adaptRecursive(source.allparams(), target.allparams());
4651 return null;
4652 }
4653
4654 @Override
4655 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
4656 if (target.hasTag(ARRAY))
4657 adaptRecursive(elemtype(source), elemtype(target));
4658 return null;
4659 }
4660
4661 @Override
4662 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
4663 if (source.isExtendsBound())
4664 adaptRecursive(wildUpperBound(source), wildUpperBound(target));
4665 else if (source.isSuperBound())
4666 adaptRecursive(wildLowerBound(source), wildLowerBound(target));
4667 return null;
4668 }
4669
4670 @Override
4671 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
4672 // Check to see if there is
4673 // already a mapping for $source$, in which case
4674 // the old mapping will be merged with the new
4675 Type val = mapping.get(source.tsym);
4676 if (val != null) {
4677 if (val.isSuperBound() && target.isSuperBound()) {
4678 val = isSubtype(wildLowerBound(val), wildLowerBound(target))
4679 ? target : val;
4680 } else if (val.isExtendsBound() && target.isExtendsBound()) {
4681 val = isSubtype(wildUpperBound(val), wildUpperBound(target))
4682 ? val : target;
4683 } else if (!isSameType(val, target)) {
4684 throw new AdaptFailure();
4685 }
4686 } else {
4687 val = target;
4688 from.append(source);
4689 to.append(target);
4690 }
4691 mapping.put(source.tsym, val);
4692 return null;
4693 }
4694
4695 @Override
4696 public Void visitType(Type source, Type target) {
4697 return null;
4698 }
4699
4700 private Set<TypePair> cache = new HashSet<>();
4701
4702 private void adaptRecursive(Type source, Type target) {
4703 TypePair pair = new TypePair(source, target);
4704 if (cache.add(pair)) {
4705 try {
4706 visit(source, target);
4707 } finally {
4708 cache.remove(pair);
4709 }
4710 }
4711 }
4712
4713 private void adaptRecursive(List<Type> source, List<Type> target) {
4714 if (source.length() == target.length()) {
4715 while (source.nonEmpty()) {
4716 adaptRecursive(source.head, target.head);
4717 source = source.tail;
4718 target = target.tail;
4719 }
4720 }
4721 }
4722 }
4723
4724 public static class AdaptFailure extends RuntimeException {
4725 static final long serialVersionUID = -7490231548272701566L;
4726 }
4727
4728 private void adaptSelf(Type t,
4729 ListBuffer<Type> from,
4730 ListBuffer<Type> to) {
4731 try {
4732 //if (t.tsym.type != t)
4733 adapt(t.tsym.type, t, from, to);
4734 } catch (AdaptFailure ex) {
4735 // Adapt should never fail calculating a mapping from
4736 // t.tsym.type to t as there can be no merge problem.
4737 throw new AssertionError(ex);
4738 }
4739 }
4740 // </editor-fold>
4741
4742 /**
4743 * Rewrite all type variables (universal quantifiers) in the given
4744 * type to wildcards (existential quantifiers). This is used to
4745 * determine if a cast is allowed. For example, if high is true
4746 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4747 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4748 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4749 * List<Integer>} with a warning.
4750 * @param t a type
4751 * @param high if true return an upper bound; otherwise a lower
4752 * bound
4753 * @param rewriteTypeVars only rewrite captured wildcards if false;
4754 * otherwise rewrite all type variables
4755 * @return the type rewritten with wildcards (existential
4756 * quantifiers) only
4757 */
4758 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4759 return new Rewriter(high, rewriteTypeVars).visit(t);
4760 }
4761
4762 class Rewriter extends UnaryVisitor<Type> {
4763
4764 boolean high;
4765 boolean rewriteTypeVars;
4766 // map to avoid visiting same type argument twice, like in Foo<T>.Bar<T>
4767 Map<Type, Type> argMap = new HashMap<>();
4768 // cycle detection within an argument, see JDK-8324809
4769 Set<Type> seen = new HashSet<>();
4770
4771 Rewriter(boolean high, boolean rewriteTypeVars) {
4772 this.high = high;
4773 this.rewriteTypeVars = rewriteTypeVars;
4774 }
4775
4776 @Override
4777 public Type visitClassType(ClassType t, Void s) {
4778 ListBuffer<Type> rewritten = new ListBuffer<>();
4779 boolean changed = false;
4780 for (Type arg : t.allparams()) {
4781 Type bound = argMap.get(arg);
4782 if (bound == null) {
4783 argMap.put(arg, bound = visit(arg));
4784 }
4785 if (arg != bound) {
4786 changed = true;
4787 }
4788 rewritten.append(bound);
4789 }
4790 if (changed)
4791 return subst(t.tsym.type,
4792 t.tsym.type.allparams(),
4793 rewritten.toList());
4794 else
4795 return t;
4796 }
4797
4798 public Type visitType(Type t, Void s) {
4799 return t;
4800 }
4801
4802 @Override
4803 public Type visitCapturedType(CapturedType t, Void s) {
4804 Type w_bound = t.wildcard.type;
4805 Type bound = w_bound.contains(t) ?
4806 erasure(w_bound) :
4807 visit(w_bound);
4808 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4809 }
4810
4811 @Override
4812 public Type visitTypeVar(TypeVar t, Void s) {
4813 if (seen.add(t)) {
4814 if (rewriteTypeVars) {
4815 Type bound = t.getUpperBound().contains(t) ?
4816 erasure(t.getUpperBound()) :
4817 visit(t.getUpperBound());
4818 return rewriteAsWildcardType(bound, t, EXTENDS);
4819 } else {
4820 return t;
4821 }
4822 } else {
4823 return rewriteTypeVars ? makeExtendsWildcard(syms.objectType, t) : t;
4824 }
4825 }
4826
4827 @Override
4828 public Type visitWildcardType(WildcardType t, Void s) {
4829 Type bound2 = visit(t.type);
4830 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4831 }
4832
4833 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4834 switch (bk) {
4835 case EXTENDS: return high ?
4836 makeExtendsWildcard(B(bound), formal) :
4837 makeExtendsWildcard(syms.objectType, formal);
4838 case SUPER: return high ?
4839 makeSuperWildcard(syms.botType, formal) :
4840 makeSuperWildcard(B(bound), formal);
4841 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4842 default:
4843 Assert.error("Invalid bound kind " + bk);
4844 return null;
4845 }
4846 }
4847
4848 Type B(Type t) {
4849 while (t.hasTag(WILDCARD)) {
4850 WildcardType w = (WildcardType)t;
4851 t = high ?
4852 w.getExtendsBound() :
4853 w.getSuperBound();
4854 if (t == null) {
4855 t = high ? syms.objectType : syms.botType;
4856 }
4857 }
4858 return t;
4859 }
4860 }
4861
4862
4863 /**
4864 * Create a wildcard with the given upper (extends) bound; create
4865 * an unbounded wildcard if bound is Object.
4866 *
4867 * @param bound the upper bound
4868 * @param formal the formal type parameter that will be
4869 * substituted by the wildcard
4870 */
4871 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4872 if (bound == syms.objectType) {
4873 return new WildcardType(syms.objectType,
4874 BoundKind.UNBOUND,
4875 syms.boundClass,
4876 formal);
4877 } else {
4878 return new WildcardType(bound,
4879 BoundKind.EXTENDS,
4880 syms.boundClass,
4881 formal);
4882 }
4883 }
4884
4885 /**
4886 * Create a wildcard with the given lower (super) bound; create an
4887 * unbounded wildcard if bound is bottom (type of {@code null}).
4888 *
4889 * @param bound the lower bound
4890 * @param formal the formal type parameter that will be
4891 * substituted by the wildcard
4892 */
4893 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4894 if (bound.hasTag(BOT)) {
4895 return new WildcardType(syms.objectType,
4896 BoundKind.UNBOUND,
4897 syms.boundClass,
4898 formal);
4899 } else {
4900 return new WildcardType(bound,
4901 BoundKind.SUPER,
4902 syms.boundClass,
4903 formal);
4904 }
4905 }
4906
4907 /**
4908 * A wrapper for a type that allows use in sets.
4909 */
4910 public static class UniqueType {
4911 public final Type type;
4912 final Types types;
4913 private boolean encodeTypeSig;
4914
4915 public UniqueType(Type type, Types types, boolean encodeTypeSig) {
4916 this.type = type;
4917 this.types = types;
4918 this.encodeTypeSig = encodeTypeSig;
4919 }
4920
4921 public UniqueType(Type type, Types types) {
4922 this(type, types, true);
4923 }
4924
4925 public int hashCode() {
4926 return types.hashCode(type);
4927 }
4928
4929 public boolean equals(Object obj) {
4930 return (obj instanceof UniqueType uniqueType) &&
4931 types.isSameType(type, uniqueType.type);
4932 }
4933
4934 public boolean encodeTypeSig() {
4935 return encodeTypeSig;
4936 }
4937
4938 public String toString() {
4939 return type.toString();
4940 }
4941
4942 }
4943 // </editor-fold>
4944
4945 // <editor-fold defaultstate="collapsed" desc="Visitors">
4946 /**
4947 * A default visitor for types. All visitor methods except
4948 * visitType are implemented by delegating to visitType. Concrete
4949 * subclasses must provide an implementation of visitType 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 * type itself) of the operation implemented by this visitor; use
4956 * Void if a second argument is not needed.
4957 */
4958 public abstract static class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4959 public final R visit(Type t, S s) { return t.accept(this, s); }
4960 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4961 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4962 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4963 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4964 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4965 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); }
4966 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4967 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4968 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4969 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4970 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4971 }
4972
4973 /**
4974 * A default visitor for symbols. All visitor methods except
4975 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4976 * subclasses must provide an implementation of visitSymbol and can
4977 * override other methods as needed.
4978 *
4979 * @param <R> the return type of the operation implemented by this
4980 * visitor; use Void if no return type is needed.
4981 * @param <S> the type of the second argument (the first being the
4982 * symbol itself) of the operation implemented by this visitor; use
4983 * Void if a second argument is not needed.
4984 */
4985 public abstract static class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4986 public final R visit(Symbol s, S arg) { return s.accept(this, arg); }
4987 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4988 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4989 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4990 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4991 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4992 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4993 }
4994
4995 /**
4996 * A <em>simple</em> visitor for types. This visitor is simple as
4997 * captured wildcards, for-all types (generic methods), and
4998 * undetermined type variables (part of inference) are hidden.
4999 * Captured wildcards are hidden by treating them as type
5000 * variables and the rest are hidden by visiting their qtypes.
5001 *
5002 * @param <R> the return type of the operation implemented by this
5003 * visitor; use Void if no return type is needed.
5004 * @param <S> the type of the second argument (the first being the
5005 * type itself) of the operation implemented by this visitor; use
5006 * Void if a second argument is not needed.
5007 */
5008 public abstract static class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
5009 @Override
5010 public R visitCapturedType(CapturedType t, S s) {
5011 return visitTypeVar(t, s);
5012 }
5013 @Override
5014 public R visitForAll(ForAll t, S s) {
5015 return visit(t.qtype, s);
5016 }
5017 @Override
5018 public R visitUndetVar(UndetVar t, S s) {
5019 return visit(t.qtype, s);
5020 }
5021 }
5022
5023 /**
5024 * A plain relation on types. That is a 2-ary function on the
5025 * form Type × Type → Boolean.
5026 * <!-- In plain text: Type x Type -> Boolean -->
5027 */
5028 public abstract static class TypeRelation extends SimpleVisitor<Boolean,Type> {}
5029
5030 /**
5031 * A convenience visitor for implementing operations that only
5032 * require one argument (the type itself), that is, unary
5033 * operations.
5034 *
5035 * @param <R> the return type of the operation implemented by this
5036 * visitor; use Void if no return type is needed.
5037 */
5038 public abstract static class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
5039 public final R visit(Type t) { return t.accept(this, null); }
5040 }
5041
5042 /**
5043 * A visitor for implementing a mapping from types to types. The
5044 * default behavior of this class is to implement the identity
5045 * mapping (mapping a type to itself). This can be overridden in
5046 * subclasses.
5047 *
5048 * @param <S> the type of the second argument (the first being the
5049 * type itself) of this mapping; use Void if a second argument is
5050 * not needed.
5051 */
5052 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
5053 public final Type visit(Type t) { return t.accept(this, null); }
5054 public Type visitType(Type t, S s) { return t; }
5055 }
5056
5057 /**
5058 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}.
5059 * This class implements the functional interface {@code Function}, that allows it to be used
5060 * fluently in stream-like processing.
5061 */
5062 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> {
5063 @Override
5064 public Type apply(Type type) { return visit(type); }
5065
5066 List<Type> visit(List<Type> ts, S s) {
5067 return ts.map(t -> visit(t, s));
5068 }
5069
5070 @Override
5071 public Type visitCapturedType(CapturedType t, S s) {
5072 return visitTypeVar(t, s);
5073 }
5074 }
5075 // </editor-fold>
5076
5077 // <editor-fold defaultstate="collapsed" desc="Unconditionality">
5078 /** Check unconditionality between any combination of reference or primitive types.
5079 *
5080 * Rules:
5081 * an identity conversion
5082 * a widening reference conversion
5083 * a widening primitive conversion (delegates to `checkUnconditionallyExactPrimitives`)
5084 * a boxing conversion
5085 * a boxing conversion followed by a widening reference conversion
5086 *
5087 * @param source Source primitive or reference type
5088 * @param target Target primitive or reference type
5089 */
5090 public boolean isUnconditionallyExact(Type source, Type target) {
5091 if (isSameType(source, target)) {
5092 return true;
5093 }
5094
5095 return target.isPrimitive()
5096 ? isUnconditionallyExactPrimitives(source, target)
5097 : isSubtype(boxedTypeOrType(erasure(source)), target);
5098 }
5099
5100 /** Check unconditionality between primitive types.
5101 *
5102 * - widening from one integral type to another,
5103 * - widening from one floating point type to another,
5104 * - widening from byte, short, or char to a floating point type,
5105 * - widening from int to double.
5106 *
5107 * @param selectorType Type of selector
5108 * @param targetType Target type
5109 */
5110 public boolean isUnconditionallyExactPrimitives(Type selectorType, Type targetType) {
5111 if (isSameType(selectorType, targetType)) {
5112 return true;
5113 }
5114
5115 return (selectorType.isPrimitive() && targetType.isPrimitive()) &&
5116 ((selectorType.hasTag(BYTE) && !targetType.hasTag(CHAR)) ||
5117 (selectorType.hasTag(SHORT) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag()))) ||
5118 (selectorType.hasTag(CHAR) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag()))) ||
5119 (selectorType.hasTag(INT) && (targetType.hasTag(DOUBLE) || targetType.hasTag(LONG))) ||
5120 (selectorType.hasTag(FLOAT) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag()))));
5121 }
5122 // </editor-fold>
5123
5124 // <editor-fold defaultstate="collapsed" desc="Annotation support">
5125
5126 public RetentionPolicy getRetention(Attribute.Compound a) {
5127 return getRetention(a.type.tsym);
5128 }
5129
5130 public RetentionPolicy getRetention(TypeSymbol sym) {
5131 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
5132 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
5133 if (c != null) {
5134 Attribute value = c.member(names.value);
5135 if (value != null && value instanceof Attribute.Enum attributeEnum) {
5136 Name levelName = attributeEnum.value.name;
5137 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
5138 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
5139 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
5140 else ;// /* fail soft */ throw new AssertionError(levelName);
5141 }
5142 }
5143 return vis;
5144 }
5145 // </editor-fold>
5146
5147 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
5148
5149 public abstract class SignatureGenerator {
5150
5151 public class InvalidSignatureException extends CompilerInternalException {
5152 private static final long serialVersionUID = 0;
5153
5154 private final transient Type type;
5155
5156 InvalidSignatureException(Type type, boolean dumpStackTraceOnError) {
5157 super(dumpStackTraceOnError);
5158 this.type = type;
5159 }
5160
5161 public Type type() {
5162 return type;
5163 }
5164 }
5165
5166 protected abstract void append(char ch);
5167 protected abstract void append(byte[] ba);
5168 protected abstract void append(Name name);
5169 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
5170
5171 protected void reportIllegalSignature(Type t) {
5172 throw new InvalidSignatureException(t, Types.this.dumpStacktraceOnError);
5173 }
5174
5175 /**
5176 * Assemble signature of given type in string buffer.
5177 */
5178 public void assembleSig(Type type) {
5179 switch (type.getTag()) {
5180 case BYTE:
5181 append('B');
5182 break;
5183 case SHORT:
5184 append('S');
5185 break;
5186 case CHAR:
5187 append('C');
5188 break;
5189 case INT:
5190 append('I');
5191 break;
5192 case LONG:
5193 append('J');
5194 break;
5195 case FLOAT:
5196 append('F');
5197 break;
5198 case DOUBLE:
5199 append('D');
5200 break;
5201 case BOOLEAN:
5202 append('Z');
5203 break;
5204 case VOID:
5205 append('V');
5206 break;
5207 case CLASS:
5208 if (type.isCompound()) {
5209 reportIllegalSignature(type);
5210 }
5211 append('L');
5212 assembleClassSig(type);
5213 append(';');
5214 break;
5215 case ARRAY:
5216 ArrayType at = (ArrayType) type;
5217 append('[');
5218 assembleSig(at.elemtype);
5219 break;
5220 case METHOD:
5221 MethodType mt = (MethodType) type;
5222 append('(');
5223 assembleSig(mt.argtypes);
5224 append(')');
5225 assembleSig(mt.restype);
5226 if (hasTypeVar(mt.thrown)) {
5227 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
5228 append('^');
5229 assembleSig(l.head);
5230 }
5231 }
5232 break;
5233 case WILDCARD: {
5234 Type.WildcardType ta = (Type.WildcardType) type;
5235 switch (ta.kind) {
5236 case SUPER:
5237 append('-');
5238 assembleSig(ta.type);
5239 break;
5240 case EXTENDS:
5241 append('+');
5242 assembleSig(ta.type);
5243 break;
5244 case UNBOUND:
5245 append('*');
5246 break;
5247 default:
5248 throw new AssertionError(ta.kind);
5249 }
5250 break;
5251 }
5252 case TYPEVAR:
5253 if (((TypeVar)type).isCaptured()) {
5254 reportIllegalSignature(type);
5255 }
5256 append('T');
5257 append(type.tsym.name);
5258 append(';');
5259 break;
5260 case FORALL:
5261 Type.ForAll ft = (Type.ForAll) type;
5262 assembleParamsSig(ft.tvars);
5263 assembleSig(ft.qtype);
5264 break;
5265 default:
5266 throw new AssertionError("typeSig " + type.getTag());
5267 }
5268 }
5269
5270 public boolean hasTypeVar(List<Type> l) {
5271 while (l.nonEmpty()) {
5272 if (l.head.hasTag(TypeTag.TYPEVAR)) {
5273 return true;
5274 }
5275 l = l.tail;
5276 }
5277 return false;
5278 }
5279
5280 public void assembleClassSig(Type type) {
5281 ClassType ct = (ClassType) type;
5282 ClassSymbol c = (ClassSymbol) ct.tsym;
5283 classReference(c);
5284 Type outer = ct.getEnclosingType();
5285 if (outer.allparams().nonEmpty()) {
5286 boolean rawOuter =
5287 c.owner.kind == MTH || // either a local class
5288 c.name == Types.this.names.empty; // or anonymous
5289 assembleClassSig(rawOuter
5290 ? Types.this.erasure(outer)
5291 : outer);
5292 append(rawOuter ? '$' : '.');
5293 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
5294 append(rawOuter
5295 ? c.flatname.subName(c.owner.enclClass().flatname.length() + 1)
5296 : c.name);
5297 } else {
5298 append(externalize(c.flatname));
5299 }
5300 if (ct.getTypeArguments().nonEmpty()) {
5301 append('<');
5302 assembleSig(ct.getTypeArguments());
5303 append('>');
5304 }
5305 }
5306
5307 public void assembleParamsSig(List<Type> typarams) {
5308 append('<');
5309 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
5310 Type.TypeVar tvar = (Type.TypeVar) ts.head;
5311 append(tvar.tsym.name);
5312 List<Type> bounds = Types.this.getBounds(tvar);
5313 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
5314 append(':');
5315 }
5316 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
5317 append(':');
5318 assembleSig(l.head);
5319 }
5320 }
5321 append('>');
5322 }
5323
5324 public void assembleSig(List<Type> types) {
5325 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
5326 assembleSig(ts.head);
5327 }
5328 }
5329 }
5330
5331 public Type constantType(LoadableConstant c) {
5332 switch (c.poolTag()) {
5333 case ClassFile.CONSTANT_Class:
5334 return syms.classType;
5335 case ClassFile.CONSTANT_String:
5336 return syms.stringType;
5337 case ClassFile.CONSTANT_Integer:
5338 return syms.intType;
5339 case ClassFile.CONSTANT_Float:
5340 return syms.floatType;
5341 case ClassFile.CONSTANT_Long:
5342 return syms.longType;
5343 case ClassFile.CONSTANT_Double:
5344 return syms.doubleType;
5345 case ClassFile.CONSTANT_MethodHandle:
5346 return syms.methodHandleType;
5347 case ClassFile.CONSTANT_MethodType:
5348 return syms.methodTypeType;
5349 case ClassFile.CONSTANT_Dynamic:
5350 return ((DynamicVarSymbol)c).type;
5351 default:
5352 throw new AssertionError("Not a loadable constant: " + c.poolTag());
5353 }
5354 }
5355 // </editor-fold>
5356
5357 public void newRound() {
5358 descCache._map.clear();
5359 isDerivedRawCache.clear();
5360 implCache._map.clear();
5361 membersCache._map.clear();
5362 closureCache.clear();
5363 }
5364 }