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