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