1 /*
2 * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.tools.javac.code;
27
28 import java.lang.ref.SoftReference;
29 import java.util.HashSet;
30 import java.util.HashMap;
31 import java.util.Locale;
32 import java.util.Map;
33 import java.util.Optional;
34 import java.util.Set;
35 import java.util.WeakHashMap;
36 import java.util.function.BiPredicate;
37 import java.util.function.Function;
38 import java.util.stream.Collector;
39
40 import javax.tools.JavaFileObject;
41
42 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
43 import com.sun.tools.javac.code.Lint.LintCategory;
44 import com.sun.tools.javac.code.Source.Feature;
45 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
46 import com.sun.tools.javac.code.TypeMetadata.Entry.Kind;
47 import com.sun.tools.javac.comp.AttrContext;
48 import com.sun.tools.javac.comp.Check;
49 import com.sun.tools.javac.comp.Enter;
50 import com.sun.tools.javac.comp.Env;
51 import com.sun.tools.javac.comp.LambdaToMethod;
52 import com.sun.tools.javac.jvm.ClassFile;
53 import com.sun.tools.javac.util.*;
54
55 import static com.sun.tools.javac.code.BoundKind.*;
56 import static com.sun.tools.javac.code.Flags.*;
57 import static com.sun.tools.javac.code.Kinds.Kind.*;
58 import static com.sun.tools.javac.code.Scope.*;
59 import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
60 import static com.sun.tools.javac.code.Symbol.*;
61 import static com.sun.tools.javac.code.Type.*;
62 import static com.sun.tools.javac.code.TypeTag.*;
63 import static com.sun.tools.javac.jvm.ClassFile.externalize;
64 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
65
66 /**
67 * Utility class containing various operations on types.
68 *
69 * <p>Unless other names are more illustrative, the following naming
70 * conventions should be observed in this file:
71 *
72 * <dl>
73 * <dt>t</dt>
74 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
75 * <dt>s</dt>
76 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
77 * <dt>ts</dt>
78 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
79 * <dt>ss</dt>
80 * <dd>A second list of types should be named ss.</dd>
81 * </dl>
82 *
83 * <p><b>This is NOT part of any supported API.
84 * If you write code that depends on this, you do so at your own risk.
85 * This code and its internal interfaces are subject to change or
86 * deletion without notice.</b>
87 */
88 public class Types {
89 protected static final Context.Key<Types> typesKey = new Context.Key<>();
90
91 final Symtab syms;
92 final JavacMessages messages;
93 final Names names;
94 final boolean allowDefaultMethods;
95 final boolean mapCapturesToBounds;
96 final Check chk;
97 final Enter enter;
98 JCDiagnostic.Factory diags;
99 List<Warner> warnStack = List.nil();
100 final Name capturedName;
101
102 public final Warner noWarnings;
103
104 // <editor-fold defaultstate="collapsed" desc="Instantiating">
105 public static Types instance(Context context) {
106 Types instance = context.get(typesKey);
107 if (instance == null)
108 instance = new Types(context);
109 return instance;
110 }
111
112 protected Types(Context context) {
113 context.put(typesKey, this);
114 syms = Symtab.instance(context);
115 names = Names.instance(context);
116 Source source = Source.instance(context);
117 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.getUpperBound();
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.getUpperBound()) : 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 transient 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 || (s.isPrimitive() &&
1643 isSubtype(boxedClass(s).type, t)));
1644 }
1645 if (warn != warnStack.head) {
1646 try {
1647 warnStack = warnStack.prepend(warn);
1648 checkUnsafeVarargsConversion(t, s, warn);
1649 return isCastable.visit(t,s);
1650 } finally {
1651 warnStack = warnStack.tail;
1652 }
1653 } else {
1654 return isCastable.visit(t,s);
1655 }
1656 }
1657 // where
1658 private TypeRelation isCastable = new TypeRelation() {
1659
1660 public Boolean visitType(Type t, Type s) {
1661 if (s.hasTag(ERROR) || t.hasTag(NONE))
1662 return true;
1663
1664 switch (t.getTag()) {
1665 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1666 case DOUBLE:
1667 return s.isNumeric();
1668 case BOOLEAN:
1669 return s.hasTag(BOOLEAN);
1670 case VOID:
1671 return false;
1672 case BOT:
1673 return isSubtype(t, s);
1674 default:
1675 throw new AssertionError();
1676 }
1677 }
1678
1679 @Override
1680 public Boolean visitWildcardType(WildcardType t, Type s) {
1681 return isCastable(wildUpperBound(t), s, warnStack.head);
1682 }
1683
1684 @Override
1685 public Boolean visitClassType(ClassType t, Type s) {
1686 if (s.hasTag(ERROR) || s.hasTag(BOT))
1687 return true;
1688
1689 if (s.hasTag(TYPEVAR)) {
1690 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1691 warnStack.head.warn(LintCategory.UNCHECKED);
1692 return true;
1693 } else {
1694 return false;
1695 }
1696 }
1697
1698 if (t.isCompound() || s.isCompound()) {
1699 return !t.isCompound() ?
1700 visitCompoundType((ClassType)s, t, true) :
1701 visitCompoundType(t, s, false);
1702 }
1703
1704 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) {
1705 boolean upcast;
1706 if ((upcast = isSubtype(erasure(t), erasure(s)))
1707 || isSubtype(erasure(s), erasure(t))) {
1708 if (!upcast && s.hasTag(ARRAY)) {
1709 if (!isReifiable(s))
1710 warnStack.head.warn(LintCategory.UNCHECKED);
1711 return true;
1712 } else if (s.isRaw()) {
1713 return true;
1714 } else if (t.isRaw()) {
1715 if (!isUnbounded(s))
1716 warnStack.head.warn(LintCategory.UNCHECKED);
1717 return true;
1718 }
1719 // Assume |a| <: |b|
1720 final Type a = upcast ? t : s;
1721 final Type b = upcast ? s : t;
1722 final boolean HIGH = true;
1723 final boolean LOW = false;
1724 final boolean DONT_REWRITE_TYPEVARS = false;
1725 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1726 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1727 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1728 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1729 Type lowSub = asSub(bLow, aLow.tsym);
1730 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1731 if (highSub == null) {
1732 final boolean REWRITE_TYPEVARS = true;
1733 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1734 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1735 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1736 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1737 lowSub = asSub(bLow, aLow.tsym);
1738 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1739 }
1740 if (highSub != null) {
1741 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1742 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1743 }
1744 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1745 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1746 && !disjointTypes(aLow.allparams(), highSub.allparams())
1747 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1748 if (upcast ? giveWarning(a, b) :
1749 giveWarning(b, a))
1750 warnStack.head.warn(LintCategory.UNCHECKED);
1751 return true;
1752 }
1753 }
1754 if (isReifiable(s))
1755 return isSubtypeUnchecked(a, b);
1756 else
1757 return isSubtypeUnchecked(a, b, warnStack.head);
1758 }
1759
1760 // Sidecast
1761 if (s.hasTag(CLASS)) {
1762 if ((s.tsym.flags() & INTERFACE) != 0) {
1763 return ((t.tsym.flags() & FINAL) == 0)
1764 ? sideCast(t, s, warnStack.head)
1765 : sideCastFinal(t, s, warnStack.head);
1766 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1767 return ((s.tsym.flags() & FINAL) == 0)
1768 ? sideCast(t, s, warnStack.head)
1769 : sideCastFinal(t, s, warnStack.head);
1770 } else {
1771 // unrelated class types
1772 return false;
1773 }
1774 }
1775 }
1776 return false;
1777 }
1778
1779 boolean visitCompoundType(ClassType ct, Type s, boolean reverse) {
1780 Warner warn = noWarnings;
1781 for (Type c : directSupertypes(ct)) {
1782 warn.clear();
1783 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1784 return false;
1785 }
1786 if (warn.hasLint(LintCategory.UNCHECKED))
1787 warnStack.head.warn(LintCategory.UNCHECKED);
1788 return true;
1789 }
1790
1791 @Override
1792 public Boolean visitArrayType(ArrayType t, Type s) {
1793 switch (s.getTag()) {
1794 case ERROR:
1795 case BOT:
1796 return true;
1797 case TYPEVAR:
1798 if (isCastable(s, t, noWarnings)) {
1799 warnStack.head.warn(LintCategory.UNCHECKED);
1800 return true;
1801 } else {
1802 return false;
1803 }
1804 case CLASS:
1805 return isSubtype(t, s);
1806 case ARRAY:
1807 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1808 return elemtype(t).hasTag(elemtype(s).getTag());
1809 } else {
1810 return visit(elemtype(t), elemtype(s));
1811 }
1812 default:
1813 return false;
1814 }
1815 }
1816
1817 @Override
1818 public Boolean visitTypeVar(TypeVar t, Type s) {
1819 switch (s.getTag()) {
1820 case ERROR:
1821 case BOT:
1822 return true;
1823 case TYPEVAR:
1824 if (isSubtype(t, s)) {
1825 return true;
1826 } else if (isCastable(t.getUpperBound(), s, noWarnings)) {
1827 warnStack.head.warn(LintCategory.UNCHECKED);
1828 return true;
1829 } else {
1830 return false;
1831 }
1832 default:
1833 return isCastable(t.getUpperBound(), s, warnStack.head);
1834 }
1835 }
1836
1837 @Override
1838 public Boolean visitErrorType(ErrorType t, Type s) {
1839 return true;
1840 }
1841 };
1842 // </editor-fold>
1843
1844 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1845 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1846 while (ts.tail != null && ss.tail != null) {
1847 if (disjointType(ts.head, ss.head)) return true;
1848 ts = ts.tail;
1849 ss = ss.tail;
1850 }
1851 return false;
1852 }
1853
1854 /**
1855 * Two types or wildcards are considered disjoint if it can be
1856 * proven that no type can be contained in both. It is
1857 * conservative in that it is allowed to say that two types are
1858 * not disjoint, even though they actually are.
1859 *
1860 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1861 * {@code X} and {@code Y} are not disjoint.
1862 */
1863 public boolean disjointType(Type t, Type s) {
1864 return disjointType.visit(t, s);
1865 }
1866 // where
1867 private TypeRelation disjointType = new TypeRelation() {
1868
1869 private Set<TypePair> cache = new HashSet<>();
1870
1871 @Override
1872 public Boolean visitType(Type t, Type s) {
1873 if (s.hasTag(WILDCARD))
1874 return visit(s, t);
1875 else
1876 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1877 }
1878
1879 private boolean isCastableRecursive(Type t, Type s) {
1880 TypePair pair = new TypePair(t, s);
1881 if (cache.add(pair)) {
1882 try {
1883 return Types.this.isCastable(t, s);
1884 } finally {
1885 cache.remove(pair);
1886 }
1887 } else {
1888 return true;
1889 }
1890 }
1891
1892 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1893 TypePair pair = new TypePair(t, s);
1894 if (cache.add(pair)) {
1895 try {
1896 return Types.this.notSoftSubtype(t, s);
1897 } finally {
1898 cache.remove(pair);
1899 }
1900 } else {
1901 return false;
1902 }
1903 }
1904
1905 @Override
1906 public Boolean visitWildcardType(WildcardType t, Type s) {
1907 if (t.isUnbound())
1908 return false;
1909
1910 if (!s.hasTag(WILDCARD)) {
1911 if (t.isExtendsBound())
1912 return notSoftSubtypeRecursive(s, t.type);
1913 else
1914 return notSoftSubtypeRecursive(t.type, s);
1915 }
1916
1917 if (s.isUnbound())
1918 return false;
1919
1920 if (t.isExtendsBound()) {
1921 if (s.isExtendsBound())
1922 return !isCastableRecursive(t.type, wildUpperBound(s));
1923 else if (s.isSuperBound())
1924 return notSoftSubtypeRecursive(wildLowerBound(s), t.type);
1925 } else if (t.isSuperBound()) {
1926 if (s.isExtendsBound())
1927 return notSoftSubtypeRecursive(t.type, wildUpperBound(s));
1928 }
1929 return false;
1930 }
1931 };
1932 // </editor-fold>
1933
1934 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds">
1935 public List<Type> cvarLowerBounds(List<Type> ts) {
1936 return ts.map(cvarLowerBoundMapping);
1937 }
1938 private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() {
1939 @Override
1940 public Type visitCapturedType(CapturedType t, Void _unused) {
1941 return cvarLowerBound(t);
1942 }
1943 };
1944 // </editor-fold>
1945
1946 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1947 /**
1948 * This relation answers the question: is impossible that
1949 * something of type `t' can be a subtype of `s'? This is
1950 * different from the question "is `t' not a subtype of `s'?"
1951 * when type variables are involved: Integer is not a subtype of T
1952 * where {@code <T extends Number>} but it is not true that Integer cannot
1953 * possibly be a subtype of T.
1954 */
1955 public boolean notSoftSubtype(Type t, Type s) {
1956 if (t == s) return false;
1957 if (t.hasTag(TYPEVAR)) {
1958 TypeVar tv = (TypeVar) t;
1959 return !isCastable(tv.getUpperBound(),
1960 relaxBound(s),
1961 noWarnings);
1962 }
1963 if (!s.hasTag(WILDCARD))
1964 s = cvarUpperBound(s);
1965
1966 return !isSubtype(t, relaxBound(s));
1967 }
1968
1969 private Type relaxBound(Type t) {
1970 return (t.hasTag(TYPEVAR)) ?
1971 rewriteQuantifiers(skipTypeVars(t, false), true, true) :
1972 t;
1973 }
1974 // </editor-fold>
1975
1976 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1977 public boolean isReifiable(Type t) {
1978 return isReifiable.visit(t);
1979 }
1980 // where
1981 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1982
1983 public Boolean visitType(Type t, Void ignored) {
1984 return true;
1985 }
1986
1987 @Override
1988 public Boolean visitClassType(ClassType t, Void ignored) {
1989 if (t.isCompound())
1990 return false;
1991 else {
1992 if (!t.isParameterized())
1993 return true;
1994
1995 for (Type param : t.allparams()) {
1996 if (!param.isUnbound())
1997 return false;
1998 }
1999 return true;
2000 }
2001 }
2002
2003 @Override
2004 public Boolean visitArrayType(ArrayType t, Void ignored) {
2005 return visit(t.elemtype);
2006 }
2007
2008 @Override
2009 public Boolean visitTypeVar(TypeVar t, Void ignored) {
2010 return false;
2011 }
2012 };
2013 // </editor-fold>
2014
2015 // <editor-fold defaultstate="collapsed" desc="Array Utils">
2016 public boolean isArray(Type t) {
2017 while (t.hasTag(WILDCARD))
2018 t = wildUpperBound(t);
2019 return t.hasTag(ARRAY);
2020 }
2021
2022 /**
2023 * The element type of an array.
2024 */
2025 public Type elemtype(Type t) {
2026 switch (t.getTag()) {
2027 case WILDCARD:
2028 return elemtype(wildUpperBound(t));
2029 case ARRAY:
2030 return ((ArrayType)t).elemtype;
2031 case FORALL:
2032 return elemtype(((ForAll)t).qtype);
2033 case ERROR:
2034 return t;
2035 default:
2036 return null;
2037 }
2038 }
2039
2040 public Type elemtypeOrType(Type t) {
2041 Type elemtype = elemtype(t);
2042 return elemtype != null ?
2043 elemtype :
2044 t;
2045 }
2046
2047 /**
2048 * Mapping to take element type of an arraytype
2049 */
2050 private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() {
2051 @Override
2052 public Type visitArrayType(ArrayType t, Void _unused) {
2053 return t.elemtype;
2054 }
2055
2056 @Override
2057 public Type visitTypeVar(TypeVar t, Void _unused) {
2058 return visit(skipTypeVars(t, false));
2059 }
2060 };
2061
2062 /**
2063 * The number of dimensions of an array type.
2064 */
2065 public int dimensions(Type t) {
2066 int result = 0;
2067 while (t.hasTag(ARRAY)) {
2068 result++;
2069 t = elemtype(t);
2070 }
2071 return result;
2072 }
2073
2074 /**
2075 * Returns an ArrayType with the component type t
2076 *
2077 * @param t The component type of the ArrayType
2078 * @return the ArrayType for the given component
2079 */
2080 public ArrayType makeArrayType(Type t) {
2081 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) {
2082 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
2083 }
2084 return new ArrayType(t, syms.arrayClass);
2085 }
2086 // </editor-fold>
2087
2088 // <editor-fold defaultstate="collapsed" desc="asSuper">
2089 /**
2090 * Return the (most specific) base type of t that starts with the
2091 * given symbol. If none exists, return null.
2092 *
2093 * Caveat Emptor: Since javac represents the class of all arrays with a singleton
2094 * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant,
2095 * this method could yield surprising answers when invoked on arrays. For example when
2096 * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null.
2097 *
2098 * @param t a type
2099 * @param sym a symbol
2100 */
2101 public Type asSuper(Type t, Symbol sym) {
2102 /* Some examples:
2103 *
2104 * (Enum<E>, Comparable) => Comparable<E>
2105 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind>
2106 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree
2107 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) =>
2108 * Iterable<capture#160 of ? extends c.s.s.d.DocTree>
2109 */
2110 if (sym.type == syms.objectType) { //optimization
2111 return syms.objectType;
2112 }
2113 return asSuper.visit(t, sym);
2114 }
2115 // where
2116 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
2117
2118 public Type visitType(Type t, Symbol sym) {
2119 return null;
2120 }
2121
2122 @Override
2123 public Type visitClassType(ClassType t, Symbol sym) {
2124 if (t.tsym == sym)
2125 return t;
2126
2127 Type st = supertype(t);
2128 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) {
2129 Type x = asSuper(st, sym);
2130 if (x != null)
2131 return x;
2132 }
2133 if ((sym.flags() & INTERFACE) != 0) {
2134 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
2135 if (!l.head.hasTag(ERROR)) {
2136 Type x = asSuper(l.head, sym);
2137 if (x != null)
2138 return x;
2139 }
2140 }
2141 }
2142 return null;
2143 }
2144
2145 @Override
2146 public Type visitArrayType(ArrayType t, Symbol sym) {
2147 return isSubtype(t, sym.type) ? sym.type : null;
2148 }
2149
2150 @Override
2151 public Type visitTypeVar(TypeVar t, Symbol sym) {
2152 if (t.tsym == sym)
2153 return t;
2154 else
2155 return asSuper(t.getUpperBound(), sym);
2156 }
2157
2158 @Override
2159 public Type visitErrorType(ErrorType t, Symbol sym) {
2160 return t;
2161 }
2162 };
2163
2164 /**
2165 * Return the base type of t or any of its outer types that starts
2166 * with the given symbol. If none exists, return null.
2167 *
2168 * @param t a type
2169 * @param sym a symbol
2170 */
2171 public Type asOuterSuper(Type t, Symbol sym) {
2172 switch (t.getTag()) {
2173 case CLASS:
2174 do {
2175 Type s = asSuper(t, sym);
2176 if (s != null) return s;
2177 t = t.getEnclosingType();
2178 } while (t.hasTag(CLASS));
2179 return null;
2180 case ARRAY:
2181 return isSubtype(t, sym.type) ? sym.type : null;
2182 case TYPEVAR:
2183 return asSuper(t, sym);
2184 case ERROR:
2185 return t;
2186 default:
2187 return null;
2188 }
2189 }
2190
2191 /**
2192 * Return the base type of t or any of its enclosing types that
2193 * starts with the given symbol. If none exists, return null.
2194 *
2195 * @param t a type
2196 * @param sym a symbol
2197 */
2198 public Type asEnclosingSuper(Type t, Symbol sym) {
2199 switch (t.getTag()) {
2200 case CLASS:
2201 do {
2202 Type s = asSuper(t, sym);
2203 if (s != null) return s;
2204 Type outer = t.getEnclosingType();
2205 t = (outer.hasTag(CLASS)) ? outer :
2206 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
2207 Type.noType;
2208 } while (t.hasTag(CLASS));
2209 return null;
2210 case ARRAY:
2211 return isSubtype(t, sym.type) ? sym.type : null;
2212 case TYPEVAR:
2213 return asSuper(t, sym);
2214 case ERROR:
2215 return t;
2216 default:
2217 return null;
2218 }
2219 }
2220 // </editor-fold>
2221
2222 // <editor-fold defaultstate="collapsed" desc="memberType">
2223 /**
2224 * The type of given symbol, seen as a member of t.
2225 *
2226 * @param t a type
2227 * @param sym a symbol
2228 */
2229 public Type memberType(Type t, Symbol sym) {
2230 return (sym.flags() & STATIC) != 0
2231 ? sym.type
2232 : memberType.visit(t, sym);
2233 }
2234 // where
2235 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
2236
2237 public Type visitType(Type t, Symbol sym) {
2238 return sym.type;
2239 }
2240
2241 @Override
2242 public Type visitWildcardType(WildcardType t, Symbol sym) {
2243 return memberType(wildUpperBound(t), sym);
2244 }
2245
2246 @Override
2247 public Type visitClassType(ClassType t, Symbol sym) {
2248 Symbol owner = sym.owner;
2249 long flags = sym.flags();
2250 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
2251 Type base = asOuterSuper(t, owner);
2252 //if t is an intersection type T = CT & I1 & I2 ... & In
2253 //its supertypes CT, I1, ... In might contain wildcards
2254 //so we need to go through capture conversion
2255 base = t.isCompound() ? capture(base) : base;
2256 if (base != null) {
2257 List<Type> ownerParams = owner.type.allparams();
2258 List<Type> baseParams = base.allparams();
2259 if (ownerParams.nonEmpty()) {
2260 if (baseParams.isEmpty()) {
2261 // then base is a raw type
2262 return erasure(sym.type);
2263 } else {
2264 return subst(sym.type, ownerParams, baseParams);
2265 }
2266 }
2267 }
2268 }
2269 return sym.type;
2270 }
2271
2272 @Override
2273 public Type visitTypeVar(TypeVar t, Symbol sym) {
2274 return memberType(t.getUpperBound(), sym);
2275 }
2276
2277 @Override
2278 public Type visitErrorType(ErrorType t, Symbol sym) {
2279 return t;
2280 }
2281 };
2282 // </editor-fold>
2283
2284 // <editor-fold defaultstate="collapsed" desc="isAssignable">
2285 public boolean isAssignable(Type t, Type s) {
2286 return isAssignable(t, s, noWarnings);
2287 }
2288
2289 /**
2290 * Is t assignable to s?<br>
2291 * Equivalent to subtype except for constant values and raw
2292 * types.<br>
2293 * (not defined for Method and ForAll types)
2294 */
2295 public boolean isAssignable(Type t, Type s, Warner warn) {
2296 if (t.hasTag(ERROR))
2297 return true;
2298 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) {
2299 int value = ((Number)t.constValue()).intValue();
2300 switch (s.getTag()) {
2301 case BYTE:
2302 case CHAR:
2303 case SHORT:
2304 case INT:
2305 if (s.getTag().checkRange(value))
2306 return true;
2307 break;
2308 case CLASS:
2309 switch (unboxedType(s).getTag()) {
2310 case BYTE:
2311 case CHAR:
2312 case SHORT:
2313 return isAssignable(t, unboxedType(s), warn);
2314 }
2315 break;
2316 }
2317 }
2318 return isConvertible(t, s, warn);
2319 }
2320 // </editor-fold>
2321
2322 // <editor-fold defaultstate="collapsed" desc="erasure">
2323 /**
2324 * The erasure of t {@code |t|} -- the type that results when all
2325 * type parameters in t are deleted.
2326 */
2327 public Type erasure(Type t) {
2328 return eraseNotNeeded(t) ? t : erasure(t, false);
2329 }
2330 //where
2331 private boolean eraseNotNeeded(Type t) {
2332 // We don't want to erase primitive types and String type as that
2333 // operation is idempotent. Also, erasing these could result in loss
2334 // of information such as constant values attached to such types.
2335 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2336 }
2337
2338 private Type erasure(Type t, boolean recurse) {
2339 if (t.isPrimitive()) {
2340 return t; /* fast special case */
2341 } else {
2342 Type out = erasure.visit(t, recurse);
2343 return out;
2344 }
2345 }
2346 // where
2347 private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() {
2348 private Type combineMetadata(final Type s,
2349 final Type t) {
2350 if (t.getMetadata() != TypeMetadata.EMPTY) {
2351 switch (s.getKind()) {
2352 case OTHER:
2353 case UNION:
2354 case INTERSECTION:
2355 case PACKAGE:
2356 case EXECUTABLE:
2357 case NONE:
2358 case VOID:
2359 case ERROR:
2360 return s;
2361 default: return s.cloneWithMetadata(s.getMetadata().without(Kind.ANNOTATIONS));
2362 }
2363 } else {
2364 return s;
2365 }
2366 }
2367
2368 public Type visitType(Type t, Boolean recurse) {
2369 if (t.isPrimitive())
2370 return t; /*fast special case*/
2371 else {
2372 //other cases already handled
2373 return combineMetadata(t, t);
2374 }
2375 }
2376
2377 @Override
2378 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2379 Type erased = erasure(wildUpperBound(t), recurse);
2380 return combineMetadata(erased, t);
2381 }
2382
2383 @Override
2384 public Type visitClassType(ClassType t, Boolean recurse) {
2385 Type erased = t.tsym.erasure(Types.this);
2386 if (recurse) {
2387 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym,
2388 t.getMetadata().without(Kind.ANNOTATIONS));
2389 return erased;
2390 } else {
2391 return combineMetadata(erased, t);
2392 }
2393 }
2394
2395 @Override
2396 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2397 Type erased = erasure(t.getUpperBound(), recurse);
2398 return combineMetadata(erased, t);
2399 }
2400 };
2401
2402 public List<Type> erasure(List<Type> ts) {
2403 return erasure.visit(ts, false);
2404 }
2405
2406 public Type erasureRecursive(Type t) {
2407 return erasure(t, true);
2408 }
2409
2410 public List<Type> erasureRecursive(List<Type> ts) {
2411 return erasure.visit(ts, true);
2412 }
2413 // </editor-fold>
2414
2415 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType">
2416 /**
2417 * Make an intersection type from non-empty list of types. The list should be ordered according to
2418 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion.
2419 * Hence, this version of makeIntersectionType may not be called during a classfile read.
2420 *
2421 * @param bounds the types from which the intersection type is formed
2422 */
2423 public IntersectionClassType makeIntersectionType(List<Type> bounds) {
2424 return makeIntersectionType(bounds, bounds.head.tsym.isInterface());
2425 }
2426
2427 /**
2428 * Make an intersection type from non-empty list of types. The list should be ordered according to
2429 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as
2430 * an extra parameter indicates as to whether all bounds are interfaces - in which case the
2431 * supertype is implicitly assumed to be 'Object'.
2432 *
2433 * @param bounds the types from which the intersection type is formed
2434 * @param allInterfaces are all bounds interface types?
2435 */
2436 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) {
2437 Assert.check(bounds.nonEmpty());
2438 Type firstExplicitBound = bounds.head;
2439 if (allInterfaces) {
2440 bounds = bounds.prepend(syms.objectType);
2441 }
2442 ClassSymbol bc =
2443 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2444 Type.moreInfo
2445 ? names.fromString(bounds.toString())
2446 : names.empty,
2447 null,
2448 syms.noSymbol);
2449 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces);
2450 bc.type = intersectionType;
2451 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
2452 syms.objectType : // error condition, recover
2453 erasure(firstExplicitBound);
2454 bc.members_field = WriteableScope.create(bc);
2455 return intersectionType;
2456 }
2457 // </editor-fold>
2458
2459 // <editor-fold defaultstate="collapsed" desc="supertype">
2460 public Type supertype(Type t) {
2461 return supertype.visit(t);
2462 }
2463 // where
2464 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2465
2466 public Type visitType(Type t, Void ignored) {
2467 // A note on wildcards: there is no good way to
2468 // determine a supertype for a super bounded wildcard.
2469 return Type.noType;
2470 }
2471
2472 @Override
2473 public Type visitClassType(ClassType t, Void ignored) {
2474 if (t.supertype_field == null) {
2475 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2476 // An interface has no superclass; its supertype is Object.
2477 if (t.isInterface())
2478 supertype = ((ClassType)t.tsym.type).supertype_field;
2479 if (t.supertype_field == null) {
2480 List<Type> actuals = classBound(t).allparams();
2481 List<Type> formals = t.tsym.type.allparams();
2482 if (t.hasErasedSupertypes()) {
2483 t.supertype_field = erasureRecursive(supertype);
2484 } else if (formals.nonEmpty()) {
2485 t.supertype_field = subst(supertype, formals, actuals);
2486 }
2487 else {
2488 t.supertype_field = supertype;
2489 }
2490 }
2491 }
2492 return t.supertype_field;
2493 }
2494
2495 /**
2496 * The supertype is always a class type. If the type
2497 * variable's bounds start with a class type, this is also
2498 * the supertype. Otherwise, the supertype is
2499 * java.lang.Object.
2500 */
2501 @Override
2502 public Type visitTypeVar(TypeVar t, Void ignored) {
2503 if (t.getUpperBound().hasTag(TYPEVAR) ||
2504 (!t.getUpperBound().isCompound() && !t.getUpperBound().isInterface())) {
2505 return t.getUpperBound();
2506 } else {
2507 return supertype(t.getUpperBound());
2508 }
2509 }
2510
2511 @Override
2512 public Type visitArrayType(ArrayType t, Void ignored) {
2513 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2514 return arraySuperType();
2515 else
2516 return new ArrayType(supertype(t.elemtype), t.tsym);
2517 }
2518
2519 @Override
2520 public Type visitErrorType(ErrorType t, Void ignored) {
2521 return Type.noType;
2522 }
2523 };
2524 // </editor-fold>
2525
2526 // <editor-fold defaultstate="collapsed" desc="interfaces">
2527 /**
2528 * Return the interfaces implemented by this class.
2529 */
2530 public List<Type> interfaces(Type t) {
2531 return interfaces.visit(t);
2532 }
2533 // where
2534 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2535
2536 public List<Type> visitType(Type t, Void ignored) {
2537 return List.nil();
2538 }
2539
2540 @Override
2541 public List<Type> visitClassType(ClassType t, Void ignored) {
2542 if (t.interfaces_field == null) {
2543 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2544 if (t.interfaces_field == null) {
2545 // If t.interfaces_field is null, then t must
2546 // be a parameterized type (not to be confused
2547 // with a generic type declaration).
2548 // Terminology:
2549 // Parameterized type: List<String>
2550 // Generic type declaration: class List<E> { ... }
2551 // So t corresponds to List<String> and
2552 // t.tsym.type corresponds to List<E>.
2553 // The reason t must be parameterized type is
2554 // that completion will happen as a side
2555 // effect of calling
2556 // ClassSymbol.getInterfaces. Since
2557 // t.interfaces_field is null after
2558 // completion, we can assume that t is not the
2559 // type of a class/interface declaration.
2560 Assert.check(t != t.tsym.type, t);
2561 List<Type> actuals = t.allparams();
2562 List<Type> formals = t.tsym.type.allparams();
2563 if (t.hasErasedSupertypes()) {
2564 t.interfaces_field = erasureRecursive(interfaces);
2565 } else if (formals.nonEmpty()) {
2566 t.interfaces_field = subst(interfaces, formals, actuals);
2567 }
2568 else {
2569 t.interfaces_field = interfaces;
2570 }
2571 }
2572 }
2573 return t.interfaces_field;
2574 }
2575
2576 @Override
2577 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2578 if (t.getUpperBound().isCompound())
2579 return interfaces(t.getUpperBound());
2580
2581 if (t.getUpperBound().isInterface())
2582 return List.of(t.getUpperBound());
2583
2584 return List.nil();
2585 }
2586 };
2587
2588 public List<Type> directSupertypes(Type t) {
2589 return directSupertypes.visit(t);
2590 }
2591 // where
2592 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() {
2593
2594 public List<Type> visitType(final Type type, final Void ignored) {
2595 if (!type.isIntersection()) {
2596 final Type sup = supertype(type);
2597 return (sup == Type.noType || sup == type || sup == null)
2598 ? interfaces(type)
2599 : interfaces(type).prepend(sup);
2600 } else {
2601 return ((IntersectionClassType)type).getExplicitComponents();
2602 }
2603 }
2604 };
2605
2606 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2607 for (Type i2 : interfaces(origin.type)) {
2608 if (isym == i2.tsym) return true;
2609 }
2610 return false;
2611 }
2612 // </editor-fold>
2613
2614 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2615 Map<Type,Boolean> isDerivedRawCache = new HashMap<>();
2616
2617 public boolean isDerivedRaw(Type t) {
2618 Boolean result = isDerivedRawCache.get(t);
2619 if (result == null) {
2620 result = isDerivedRawInternal(t);
2621 isDerivedRawCache.put(t, result);
2622 }
2623 return result;
2624 }
2625
2626 public boolean isDerivedRawInternal(Type t) {
2627 if (t.isErroneous())
2628 return false;
2629 return
2630 t.isRaw() ||
2631 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) ||
2632 isDerivedRaw(interfaces(t));
2633 }
2634
2635 public boolean isDerivedRaw(List<Type> ts) {
2636 List<Type> l = ts;
2637 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2638 return l.nonEmpty();
2639 }
2640 // </editor-fold>
2641
2642 // <editor-fold defaultstate="collapsed" desc="setBounds">
2643 /**
2644 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly,
2645 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise
2646 * the supertype is simply left null (in this case, the supertype is assumed to be the head of
2647 * the bound list passed as second argument). Note that this check might cause a symbol completion.
2648 * Hence, this version of setBounds may not be called during a classfile read.
2649 *
2650 * @param t a type variable
2651 * @param bounds the bounds, must be nonempty
2652 */
2653 public void setBounds(TypeVar t, List<Type> bounds) {
2654 setBounds(t, bounds, bounds.head.tsym.isInterface());
2655 }
2656
2657 /**
2658 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds.
2659 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds
2660 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'.
2661 *
2662 * @param t a type variable
2663 * @param bounds the bounds, must be nonempty
2664 * @param allInterfaces are all bounds interface types?
2665 */
2666 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2667 t.setUpperBound( bounds.tail.isEmpty() ?
2668 bounds.head :
2669 makeIntersectionType(bounds, allInterfaces) );
2670 t.rank_field = -1;
2671 }
2672 // </editor-fold>
2673
2674 // <editor-fold defaultstate="collapsed" desc="getBounds">
2675 /**
2676 * Return list of bounds of the given type variable.
2677 */
2678 public List<Type> getBounds(TypeVar t) {
2679 if (t.getUpperBound().hasTag(NONE))
2680 return List.nil();
2681 else if (t.getUpperBound().isErroneous() || !t.getUpperBound().isCompound())
2682 return List.of(t.getUpperBound());
2683 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2684 return interfaces(t).prepend(supertype(t));
2685 else
2686 // No superclass was given in bounds.
2687 // In this case, supertype is Object, erasure is first interface.
2688 return interfaces(t);
2689 }
2690 // </editor-fold>
2691
2692 // <editor-fold defaultstate="collapsed" desc="classBound">
2693 /**
2694 * If the given type is a (possibly selected) type variable,
2695 * return the bounding class of this type, otherwise return the
2696 * type itself.
2697 */
2698 public Type classBound(Type t) {
2699 return classBound.visit(t);
2700 }
2701 // where
2702 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2703
2704 public Type visitType(Type t, Void ignored) {
2705 return t;
2706 }
2707
2708 @Override
2709 public Type visitClassType(ClassType t, Void ignored) {
2710 Type outer1 = classBound(t.getEnclosingType());
2711 if (outer1 != t.getEnclosingType())
2712 return new ClassType(outer1, t.getTypeArguments(), t.tsym,
2713 t.getMetadata());
2714 else
2715 return t;
2716 }
2717
2718 @Override
2719 public Type visitTypeVar(TypeVar t, Void ignored) {
2720 return classBound(supertype(t));
2721 }
2722
2723 @Override
2724 public Type visitErrorType(ErrorType t, Void ignored) {
2725 return t;
2726 }
2727 };
2728 // </editor-fold>
2729
2730 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
2731 /**
2732 * Returns true iff the first signature is a <em>sub
2733 * signature</em> of the other. This is <b>not</b> an equivalence
2734 * relation.
2735 *
2736 * @jls 8.4.2 Method Signature
2737 * @see #overrideEquivalent(Type t, Type s)
2738 * @param t first signature (possibly raw).
2739 * @param s second signature (could be subjected to erasure).
2740 * @return true if t is a sub signature of s.
2741 */
2742 public boolean isSubSignature(Type t, Type s) {
2743 return isSubSignature(t, s, true);
2744 }
2745
2746 public boolean isSubSignature(Type t, Type s, boolean strict) {
2747 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2748 }
2749
2750 /**
2751 * Returns true iff these signatures are related by <em>override
2752 * equivalence</em>. This is the natural extension of
2753 * isSubSignature to an equivalence relation.
2754 *
2755 * @jls 8.4.2 Method Signature
2756 * @see #isSubSignature(Type t, Type s)
2757 * @param t a signature (possible raw, could be subjected to
2758 * erasure).
2759 * @param s a signature (possible raw, could be subjected to
2760 * erasure).
2761 * @return true if either argument is a sub signature of the other.
2762 */
2763 public boolean overrideEquivalent(Type t, Type s) {
2764 return hasSameArgs(t, s) ||
2765 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2766 }
2767
2768 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2769 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) {
2770 if (msym.overrides(sym, origin, Types.this, true)) {
2771 return true;
2772 }
2773 }
2774 return false;
2775 }
2776
2777 /**
2778 * This enum defines the strategy for implementing most specific return type check
2779 * during the most specific and functional interface checks.
2780 */
2781 public enum MostSpecificReturnCheck {
2782 /**
2783 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling
2784 * method type variables (if either method is generic) and (ii) subtyping should be replaced
2785 * by type-equivalence for primitives. This is essentially an inlined version of
2786 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been
2787 * replaced with a strict subtyping check.
2788 */
2789 BASIC() {
2790 @Override
2791 public boolean test(Type mt1, Type mt2, Types types) {
2792 List<Type> tvars = mt1.getTypeArguments();
2793 List<Type> svars = mt2.getTypeArguments();
2794 Type t = mt1.getReturnType();
2795 Type s = types.subst(mt2.getReturnType(), svars, tvars);
2796 return types.isSameType(t, s) ||
2797 !t.isPrimitive() &&
2798 !s.isPrimitive() &&
2799 types.isSubtype(t, s);
2800 }
2801 },
2802 /**
2803 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2.
2804 */
2805 RTS() {
2806 @Override
2807 public boolean test(Type mt1, Type mt2, Types types) {
2808 return types.returnTypeSubstitutable(mt1, mt2);
2809 }
2810 };
2811
2812 public abstract boolean test(Type mt1, Type mt2, Types types);
2813 }
2814
2815 /**
2816 * Merge multiple abstract methods. The preferred method is a method that is a subsignature
2817 * of all the other signatures and whose return type is more specific {@see MostSpecificReturnCheck}.
2818 * The resulting preferred method has a thrown clause that is the intersection of the merged
2819 * methods' clauses.
2820 */
2821 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) {
2822 //first check for preconditions
2823 boolean shouldErase = false;
2824 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes();
2825 for (Symbol s : ambiguousInOrder) {
2826 if ((s.flags() & ABSTRACT) == 0 ||
2827 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) {
2828 return Optional.empty();
2829 } else if (s.type.hasTag(FORALL)) {
2830 shouldErase = true;
2831 }
2832 }
2833 //then merge abstracts
2834 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) {
2835 outer: for (Symbol s : ambiguousInOrder) {
2836 Type mt = memberType(site, s);
2837 List<Type> allThrown = mt.getThrownTypes();
2838 for (Symbol s2 : ambiguousInOrder) {
2839 if (s != s2) {
2840 Type mt2 = memberType(site, s2);
2841 if (!isSubSignature(mt, mt2) ||
2842 !mostSpecificReturnCheck.test(mt, mt2, this)) {
2843 //ambiguity cannot be resolved
2844 continue outer;
2845 } else {
2846 List<Type> thrownTypes2 = mt2.getThrownTypes();
2847 if (!mt.hasTag(FORALL) && shouldErase) {
2848 thrownTypes2 = erasure(thrownTypes2);
2849 } else if (mt.hasTag(FORALL)) {
2850 //subsignature implies that if most specific is generic, then all other
2851 //methods are too
2852 Assert.check(mt2.hasTag(FORALL));
2853 // if both are generic methods, adjust thrown types ahead of intersection computation
2854 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments());
2855 }
2856 allThrown = chk.intersect(allThrown, thrownTypes2);
2857 }
2858 }
2859 }
2860 return (allThrown == mt.getThrownTypes()) ?
2861 Optional.of(s) :
2862 Optional.of(new MethodSymbol(
2863 s.flags(),
2864 s.name,
2865 createMethodTypeWithThrown(s.type, allThrown),
2866 s.owner) {
2867 @Override
2868 public Symbol baseSymbol() {
2869 return s;
2870 }
2871 });
2872 }
2873 }
2874 return Optional.empty();
2875 }
2876
2877 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2878 class ImplementationCache {
2879
2880 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>();
2881
2882 class Entry {
2883 final MethodSymbol cachedImpl;
2884 final Filter<Symbol> implFilter;
2885 final boolean checkResult;
2886 final int prevMark;
2887
2888 public Entry(MethodSymbol cachedImpl,
2889 Filter<Symbol> scopeFilter,
2890 boolean checkResult,
2891 int prevMark) {
2892 this.cachedImpl = cachedImpl;
2893 this.implFilter = scopeFilter;
2894 this.checkResult = checkResult;
2895 this.prevMark = prevMark;
2896 }
2897
2898 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2899 return this.implFilter == scopeFilter &&
2900 this.checkResult == checkResult &&
2901 this.prevMark == mark;
2902 }
2903 }
2904
2905 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2906 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2907 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2908 if (cache == null) {
2909 cache = new HashMap<>();
2910 _map.put(ms, new SoftReference<>(cache));
2911 }
2912 Entry e = cache.get(origin);
2913 CompoundScope members = membersClosure(origin.type, true);
2914 if (e == null ||
2915 !e.matches(implFilter, checkResult, members.getMark())) {
2916 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2917 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2918 return impl;
2919 }
2920 else {
2921 return e.cachedImpl;
2922 }
2923 }
2924
2925 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2926 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
2927 t = skipTypeVars(t, false);
2928 TypeSymbol c = t.tsym;
2929 Symbol bestSoFar = null;
2930 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) {
2931 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) {
2932 bestSoFar = sym;
2933 if ((sym.flags() & ABSTRACT) == 0) {
2934 //if concrete impl is found, exit immediately
2935 break;
2936 }
2937 }
2938 }
2939 if (bestSoFar != null) {
2940 //return either the (only) concrete implementation or the first abstract one
2941 return (MethodSymbol)bestSoFar;
2942 }
2943 }
2944 return null;
2945 }
2946 }
2947
2948 private ImplementationCache implCache = new ImplementationCache();
2949
2950 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2951 return implCache.get(ms, origin, checkResult, implFilter);
2952 }
2953 // </editor-fold>
2954
2955 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2956 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> {
2957
2958 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>();
2959
2960 Set<TypeSymbol> seenTypes = new HashSet<>();
2961
2962 class MembersScope extends CompoundScope {
2963
2964 CompoundScope scope;
2965
2966 public MembersScope(CompoundScope scope) {
2967 super(scope.owner);
2968 this.scope = scope;
2969 }
2970
2971 Filter<Symbol> combine(Filter<Symbol> sf) {
2972 return s -> !s.owner.isInterface() && (sf == null || sf.accepts(s));
2973 }
2974
2975 @Override
2976 public Iterable<Symbol> getSymbols(Filter<Symbol> sf, LookupKind lookupKind) {
2977 return scope.getSymbols(combine(sf), lookupKind);
2978 }
2979
2980 @Override
2981 public Iterable<Symbol> getSymbolsByName(Name name, Filter<Symbol> sf, LookupKind lookupKind) {
2982 return scope.getSymbolsByName(name, combine(sf), lookupKind);
2983 }
2984
2985 @Override
2986 public int getMark() {
2987 return scope.getMark();
2988 }
2989 }
2990
2991 CompoundScope nilScope;
2992
2993 /** members closure visitor methods **/
2994
2995 public CompoundScope visitType(Type t, Void _unused) {
2996 if (nilScope == null) {
2997 nilScope = new CompoundScope(syms.noSymbol);
2998 }
2999 return nilScope;
3000 }
3001
3002 @Override
3003 public CompoundScope visitClassType(ClassType t, Void _unused) {
3004 if (!seenTypes.add(t.tsym)) {
3005 //this is possible when an interface is implemented in multiple
3006 //superclasses, or when a class hierarchy is circular - in such
3007 //cases we don't need to recurse (empty scope is returned)
3008 return new CompoundScope(t.tsym);
3009 }
3010 try {
3011 seenTypes.add(t.tsym);
3012 ClassSymbol csym = (ClassSymbol)t.tsym;
3013 CompoundScope membersClosure = _map.get(csym);
3014 if (membersClosure == null) {
3015 membersClosure = new CompoundScope(csym);
3016 for (Type i : interfaces(t)) {
3017 membersClosure.prependSubScope(visit(i, null));
3018 }
3019 membersClosure.prependSubScope(visit(supertype(t), null));
3020 membersClosure.prependSubScope(csym.members());
3021 _map.put(csym, membersClosure);
3022 }
3023 return membersClosure;
3024 }
3025 finally {
3026 seenTypes.remove(t.tsym);
3027 }
3028 }
3029
3030 @Override
3031 public CompoundScope visitTypeVar(TypeVar t, Void _unused) {
3032 return visit(t.getUpperBound(), null);
3033 }
3034 }
3035
3036 private MembersClosureCache membersCache = new MembersClosureCache();
3037
3038 public CompoundScope membersClosure(Type site, boolean skipInterface) {
3039 CompoundScope cs = membersCache.visit(site, null);
3040 Assert.checkNonNull(cs, () -> "type " + site);
3041 return skipInterface ? membersCache.new MembersScope(cs) : cs;
3042 }
3043 // </editor-fold>
3044
3045
3046 /** Return first abstract member of class `sym'.
3047 */
3048 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) {
3049 try {
3050 return firstUnimplementedAbstractImpl(sym, sym);
3051 } catch (CompletionFailure ex) {
3052 chk.completionError(enter.getEnv(sym).tree.pos(), ex);
3053 return null;
3054 }
3055 }
3056 //where:
3057 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) {
3058 MethodSymbol undef = null;
3059 // Do not bother to search in classes that are not abstract,
3060 // since they cannot have abstract members.
3061 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
3062 Scope s = c.members();
3063 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
3064 if (sym.kind == MTH &&
3065 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
3066 MethodSymbol absmeth = (MethodSymbol)sym;
3067 MethodSymbol implmeth = absmeth.implementation(impl, this, true);
3068 if (implmeth == null || implmeth == absmeth) {
3069 //look for default implementations
3070 if (allowDefaultMethods) {
3071 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head;
3072 if (prov != null && prov.overrides(absmeth, impl, this, true)) {
3073 implmeth = prov;
3074 }
3075 }
3076 }
3077 if (implmeth == null || implmeth == absmeth) {
3078 undef = absmeth;
3079 break;
3080 }
3081 }
3082 }
3083 if (undef == null) {
3084 Type st = supertype(c.type);
3085 if (st.hasTag(CLASS))
3086 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym);
3087 }
3088 for (List<Type> l = interfaces(c.type);
3089 undef == null && l.nonEmpty();
3090 l = l.tail) {
3091 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym);
3092 }
3093 }
3094 return undef;
3095 }
3096
3097 public class CandidatesCache {
3098 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>();
3099
3100 class Entry {
3101 Type site;
3102 MethodSymbol msym;
3103
3104 Entry(Type site, MethodSymbol msym) {
3105 this.site = site;
3106 this.msym = msym;
3107 }
3108
3109 @Override
3110 public boolean equals(Object obj) {
3111 if (obj instanceof Entry) {
3112 Entry e = (Entry)obj;
3113 return e.msym == msym && isSameType(site, e.site);
3114 } else {
3115 return false;
3116 }
3117 }
3118
3119 @Override
3120 public int hashCode() {
3121 return Types.this.hashCode(site) & ~msym.hashCode();
3122 }
3123 }
3124
3125 public List<MethodSymbol> get(Entry e) {
3126 return cache.get(e);
3127 }
3128
3129 public void put(Entry e, List<MethodSymbol> msymbols) {
3130 cache.put(e, msymbols);
3131 }
3132 }
3133
3134 public CandidatesCache candidatesCache = new CandidatesCache();
3135
3136 //where
3137 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
3138 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms);
3139 List<MethodSymbol> candidates = candidatesCache.get(e);
3140 if (candidates == null) {
3141 Filter<Symbol> filter = new MethodFilter(ms, site);
3142 List<MethodSymbol> candidates2 = List.nil();
3143 for (Symbol s : membersClosure(site, false).getSymbols(filter)) {
3144 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
3145 return List.of((MethodSymbol)s);
3146 } else if (!candidates2.contains(s)) {
3147 candidates2 = candidates2.prepend((MethodSymbol)s);
3148 }
3149 }
3150 candidates = prune(candidates2);
3151 candidatesCache.put(e, candidates);
3152 }
3153 return candidates;
3154 }
3155
3156 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
3157 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>();
3158 for (MethodSymbol m1 : methods) {
3159 boolean isMin_m1 = true;
3160 for (MethodSymbol m2 : methods) {
3161 if (m1 == m2) continue;
3162 if (m2.owner != m1.owner &&
3163 asSuper(m2.owner.type, m1.owner) != null) {
3164 isMin_m1 = false;
3165 break;
3166 }
3167 }
3168 if (isMin_m1)
3169 methodsMin.append(m1);
3170 }
3171 return methodsMin.toList();
3172 }
3173 // where
3174 private class MethodFilter implements Filter<Symbol> {
3175
3176 Symbol msym;
3177 Type site;
3178
3179 MethodFilter(Symbol msym, Type site) {
3180 this.msym = msym;
3181 this.site = site;
3182 }
3183
3184 public boolean accepts(Symbol s) {
3185 return s.kind == MTH &&
3186 s.name == msym.name &&
3187 (s.flags() & SYNTHETIC) == 0 &&
3188 s.isInheritedIn(site.tsym, Types.this) &&
3189 overrideEquivalent(memberType(site, s), memberType(site, msym));
3190 }
3191 }
3192 // </editor-fold>
3193
3194 /**
3195 * Does t have the same arguments as s? It is assumed that both
3196 * types are (possibly polymorphic) method types. Monomorphic
3197 * method types "have the same arguments", if their argument lists
3198 * are equal. Polymorphic method types "have the same arguments",
3199 * if they have the same arguments after renaming all type
3200 * variables of one to corresponding type variables in the other,
3201 * where correspondence is by position in the type parameter list.
3202 */
3203 public boolean hasSameArgs(Type t, Type s) {
3204 return hasSameArgs(t, s, true);
3205 }
3206
3207 public boolean hasSameArgs(Type t, Type s, boolean strict) {
3208 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
3209 }
3210
3211 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
3212 return hasSameArgs.visit(t, s);
3213 }
3214 // where
3215 private class HasSameArgs extends TypeRelation {
3216
3217 boolean strict;
3218
3219 public HasSameArgs(boolean strict) {
3220 this.strict = strict;
3221 }
3222
3223 public Boolean visitType(Type t, Type s) {
3224 throw new AssertionError();
3225 }
3226
3227 @Override
3228 public Boolean visitMethodType(MethodType t, Type s) {
3229 return s.hasTag(METHOD)
3230 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
3231 }
3232
3233 @Override
3234 public Boolean visitForAll(ForAll t, Type s) {
3235 if (!s.hasTag(FORALL))
3236 return strict ? false : visitMethodType(t.asMethodType(), s);
3237
3238 ForAll forAll = (ForAll)s;
3239 return hasSameBounds(t, forAll)
3240 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
3241 }
3242
3243 @Override
3244 public Boolean visitErrorType(ErrorType t, Type s) {
3245 return false;
3246 }
3247 }
3248
3249 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
3250 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
3251
3252 // </editor-fold>
3253
3254 // <editor-fold defaultstate="collapsed" desc="subst">
3255 public List<Type> subst(List<Type> ts,
3256 List<Type> from,
3257 List<Type> to) {
3258 return ts.map(new Subst(from, to));
3259 }
3260
3261 /**
3262 * Substitute all occurrences of a type in `from' with the
3263 * corresponding type in `to' in 't'. Match lists `from' and `to'
3264 * from the right: If lists have different length, discard leading
3265 * elements of the longer list.
3266 */
3267 public Type subst(Type t, List<Type> from, List<Type> to) {
3268 return t.map(new Subst(from, to));
3269 }
3270
3271 private class Subst extends StructuralTypeMapping<Void> {
3272 List<Type> from;
3273 List<Type> to;
3274
3275 public Subst(List<Type> from, List<Type> to) {
3276 int fromLength = from.length();
3277 int toLength = to.length();
3278 while (fromLength > toLength) {
3279 fromLength--;
3280 from = from.tail;
3281 }
3282 while (fromLength < toLength) {
3283 toLength--;
3284 to = to.tail;
3285 }
3286 this.from = from;
3287 this.to = to;
3288 }
3289
3290 @Override
3291 public Type visitTypeVar(TypeVar t, Void ignored) {
3292 for (List<Type> from = this.from, to = this.to;
3293 from.nonEmpty();
3294 from = from.tail, to = to.tail) {
3295 if (t.equalsIgnoreMetadata(from.head)) {
3296 return to.head.withTypeVar(t);
3297 }
3298 }
3299 return t;
3300 }
3301
3302 @Override
3303 public Type visitClassType(ClassType t, Void ignored) {
3304 if (!t.isCompound()) {
3305 return super.visitClassType(t, ignored);
3306 } else {
3307 Type st = visit(supertype(t));
3308 List<Type> is = visit(interfaces(t), ignored);
3309 if (st == supertype(t) && is == interfaces(t))
3310 return t;
3311 else
3312 return makeIntersectionType(is.prepend(st));
3313 }
3314 }
3315
3316 @Override
3317 public Type visitWildcardType(WildcardType t, Void ignored) {
3318 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored);
3319 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) {
3320 t2.type = wildUpperBound(t2.type);
3321 }
3322 return t2;
3323 }
3324
3325 @Override
3326 public Type visitForAll(ForAll t, Void ignored) {
3327 if (Type.containsAny(to, t.tvars)) {
3328 //perform alpha-renaming of free-variables in 't'
3329 //if 'to' types contain variables that are free in 't'
3330 List<Type> freevars = newInstances(t.tvars);
3331 t = new ForAll(freevars,
3332 Types.this.subst(t.qtype, t.tvars, freevars));
3333 }
3334 List<Type> tvars1 = substBounds(t.tvars, from, to);
3335 Type qtype1 = visit(t.qtype);
3336 if (tvars1 == t.tvars && qtype1 == t.qtype) {
3337 return t;
3338 } else if (tvars1 == t.tvars) {
3339 return new ForAll(tvars1, qtype1) {
3340 @Override
3341 public boolean needsStripping() {
3342 return true;
3343 }
3344 };
3345 } else {
3346 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) {
3347 @Override
3348 public boolean needsStripping() {
3349 return true;
3350 }
3351 };
3352 }
3353 }
3354 }
3355
3356 public List<Type> substBounds(List<Type> tvars,
3357 List<Type> from,
3358 List<Type> to) {
3359 if (tvars.isEmpty())
3360 return tvars;
3361 ListBuffer<Type> newBoundsBuf = new ListBuffer<>();
3362 boolean changed = false;
3363 // calculate new bounds
3364 for (Type t : tvars) {
3365 TypeVar tv = (TypeVar) t;
3366 Type bound = subst(tv.getUpperBound(), from, to);
3367 if (bound != tv.getUpperBound())
3368 changed = true;
3369 newBoundsBuf.append(bound);
3370 }
3371 if (!changed)
3372 return tvars;
3373 ListBuffer<Type> newTvars = new ListBuffer<>();
3374 // create new type variables without bounds
3375 for (Type t : tvars) {
3376 newTvars.append(new TypeVar(t.tsym, null, syms.botType,
3377 t.getMetadata()));
3378 }
3379 // the new bounds should use the new type variables in place
3380 // of the old
3381 List<Type> newBounds = newBoundsBuf.toList();
3382 from = tvars;
3383 to = newTvars.toList();
3384 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
3385 newBounds.head = subst(newBounds.head, from, to);
3386 }
3387 newBounds = newBoundsBuf.toList();
3388 // set the bounds of new type variables to the new bounds
3389 for (Type t : newTvars.toList()) {
3390 TypeVar tv = (TypeVar) t;
3391 tv.setUpperBound( newBounds.head );
3392 newBounds = newBounds.tail;
3393 }
3394 return newTvars.toList();
3395 }
3396
3397 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
3398 Type bound1 = subst(t.getUpperBound(), from, to);
3399 if (bound1 == t.getUpperBound())
3400 return t;
3401 else {
3402 // create new type variable without bounds
3403 TypeVar tv = new TypeVar(t.tsym, null, syms.botType,
3404 t.getMetadata());
3405 // the new bound should use the new type variable in place
3406 // of the old
3407 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) );
3408 return tv;
3409 }
3410 }
3411 // </editor-fold>
3412
3413 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
3414 /**
3415 * Does t have the same bounds for quantified variables as s?
3416 */
3417 public boolean hasSameBounds(ForAll t, ForAll s) {
3418 List<Type> l1 = t.tvars;
3419 List<Type> l2 = s.tvars;
3420 while (l1.nonEmpty() && l2.nonEmpty() &&
3421 isSameType(l1.head.getUpperBound(),
3422 subst(l2.head.getUpperBound(),
3423 s.tvars,
3424 t.tvars))) {
3425 l1 = l1.tail;
3426 l2 = l2.tail;
3427 }
3428 return l1.isEmpty() && l2.isEmpty();
3429 }
3430 // </editor-fold>
3431
3432 // <editor-fold defaultstate="collapsed" desc="newInstances">
3433 /** Create new vector of type variables from list of variables
3434 * changing all recursive bounds from old to new list.
3435 */
3436 public List<Type> newInstances(List<Type> tvars) {
3437 List<Type> tvars1 = tvars.map(newInstanceFun);
3438 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
3439 TypeVar tv = (TypeVar) l.head;
3440 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) );
3441 }
3442 return tvars1;
3443 }
3444 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() {
3445 @Override
3446 public TypeVar visitTypeVar(TypeVar t, Void _unused) {
3447 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata());
3448 }
3449 };
3450 // </editor-fold>
3451
3452 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
3453 return original.accept(methodWithParameters, newParams);
3454 }
3455 // where
3456 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
3457 public Type visitType(Type t, List<Type> newParams) {
3458 throw new IllegalArgumentException("Not a method type: " + t);
3459 }
3460 public Type visitMethodType(MethodType t, List<Type> newParams) {
3461 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
3462 }
3463 public Type visitForAll(ForAll t, List<Type> newParams) {
3464 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
3465 }
3466 };
3467
3468 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
3469 return original.accept(methodWithThrown, newThrown);
3470 }
3471 // where
3472 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
3473 public Type visitType(Type t, List<Type> newThrown) {
3474 throw new IllegalArgumentException("Not a method type: " + t);
3475 }
3476 public Type visitMethodType(MethodType t, List<Type> newThrown) {
3477 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
3478 }
3479 public Type visitForAll(ForAll t, List<Type> newThrown) {
3480 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
3481 }
3482 };
3483
3484 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
3485 return original.accept(methodWithReturn, newReturn);
3486 }
3487 // where
3488 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
3489 public Type visitType(Type t, Type newReturn) {
3490 throw new IllegalArgumentException("Not a method type: " + t);
3491 }
3492 public Type visitMethodType(MethodType t, Type newReturn) {
3493 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) {
3494 @Override
3495 public Type baseType() {
3496 return t;
3497 }
3498 };
3499 }
3500 public Type visitForAll(ForAll t, Type newReturn) {
3501 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) {
3502 @Override
3503 public Type baseType() {
3504 return t;
3505 }
3506 };
3507 }
3508 };
3509
3510 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3511 public Type createErrorType(Type originalType) {
3512 return new ErrorType(originalType, syms.errSymbol);
3513 }
3514
3515 public Type createErrorType(ClassSymbol c, Type originalType) {
3516 return new ErrorType(c, originalType);
3517 }
3518
3519 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3520 return new ErrorType(name, container, originalType);
3521 }
3522 // </editor-fold>
3523
3524 // <editor-fold defaultstate="collapsed" desc="rank">
3525 /**
3526 * The rank of a class is the length of the longest path between
3527 * the class and java.lang.Object in the class inheritance
3528 * graph. Undefined for all but reference types.
3529 */
3530 public int rank(Type t) {
3531 switch(t.getTag()) {
3532 case CLASS: {
3533 ClassType cls = (ClassType)t;
3534 if (cls.rank_field < 0) {
3535 Name fullname = cls.tsym.getQualifiedName();
3536 if (fullname == names.java_lang_Object)
3537 cls.rank_field = 0;
3538 else {
3539 int r = rank(supertype(cls));
3540 for (List<Type> l = interfaces(cls);
3541 l.nonEmpty();
3542 l = l.tail) {
3543 if (rank(l.head) > r)
3544 r = rank(l.head);
3545 }
3546 cls.rank_field = r + 1;
3547 }
3548 }
3549 return cls.rank_field;
3550 }
3551 case TYPEVAR: {
3552 TypeVar tvar = (TypeVar)t;
3553 if (tvar.rank_field < 0) {
3554 int r = rank(supertype(tvar));
3555 for (List<Type> l = interfaces(tvar);
3556 l.nonEmpty();
3557 l = l.tail) {
3558 if (rank(l.head) > r) r = rank(l.head);
3559 }
3560 tvar.rank_field = r + 1;
3561 }
3562 return tvar.rank_field;
3563 }
3564 case ERROR:
3565 case NONE:
3566 return 0;
3567 default:
3568 throw new AssertionError();
3569 }
3570 }
3571 // </editor-fold>
3572
3573 /**
3574 * Helper method for generating a string representation of a given type
3575 * accordingly to a given locale
3576 */
3577 public String toString(Type t, Locale locale) {
3578 return Printer.createStandardPrinter(messages).visit(t, locale);
3579 }
3580
3581 /**
3582 * Helper method for generating a string representation of a given type
3583 * accordingly to a given locale
3584 */
3585 public String toString(Symbol t, Locale locale) {
3586 return Printer.createStandardPrinter(messages).visit(t, locale);
3587 }
3588
3589 // <editor-fold defaultstate="collapsed" desc="toString">
3590 /**
3591 * This toString is slightly more descriptive than the one on Type.
3592 *
3593 * @deprecated Types.toString(Type t, Locale l) provides better support
3594 * for localization
3595 */
3596 @Deprecated
3597 public String toString(Type t) {
3598 if (t.hasTag(FORALL)) {
3599 ForAll forAll = (ForAll)t;
3600 return typaramsString(forAll.tvars) + forAll.qtype;
3601 }
3602 return "" + t;
3603 }
3604 // where
3605 private String typaramsString(List<Type> tvars) {
3606 StringBuilder s = new StringBuilder();
3607 s.append('<');
3608 boolean first = true;
3609 for (Type t : tvars) {
3610 if (!first) s.append(", ");
3611 first = false;
3612 appendTyparamString(((TypeVar)t), s);
3613 }
3614 s.append('>');
3615 return s.toString();
3616 }
3617 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3618 buf.append(t);
3619 if (t.getUpperBound() == null ||
3620 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object)
3621 return;
3622 buf.append(" extends "); // Java syntax; no need for i18n
3623 Type bound = t.getUpperBound();
3624 if (!bound.isCompound()) {
3625 buf.append(bound);
3626 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3627 buf.append(supertype(t));
3628 for (Type intf : interfaces(t)) {
3629 buf.append('&');
3630 buf.append(intf);
3631 }
3632 } else {
3633 // No superclass was given in bounds.
3634 // In this case, supertype is Object, erasure is first interface.
3635 boolean first = true;
3636 for (Type intf : interfaces(t)) {
3637 if (!first) buf.append('&');
3638 first = false;
3639 buf.append(intf);
3640 }
3641 }
3642 }
3643 // </editor-fold>
3644
3645 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3646 /**
3647 * A cache for closures.
3648 *
3649 * <p>A closure is a list of all the supertypes and interfaces of
3650 * a class or interface type, ordered by ClassSymbol.precedes
3651 * (that is, subclasses come first, arbitrary but fixed
3652 * otherwise).
3653 */
3654 private Map<Type,List<Type>> closureCache = new HashMap<>();
3655
3656 /**
3657 * Returns the closure of a class or interface type.
3658 */
3659 public List<Type> closure(Type t) {
3660 List<Type> cl = closureCache.get(t);
3661 if (cl == null) {
3662 Type st = supertype(t);
3663 if (!t.isCompound()) {
3664 if (st.hasTag(CLASS)) {
3665 cl = insert(closure(st), t);
3666 } else if (st.hasTag(TYPEVAR)) {
3667 cl = closure(st).prepend(t);
3668 } else {
3669 cl = List.of(t);
3670 }
3671 } else {
3672 cl = closure(supertype(t));
3673 }
3674 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3675 cl = union(cl, closure(l.head));
3676 closureCache.put(t, cl);
3677 }
3678 return cl;
3679 }
3680
3681 /**
3682 * Collect types into a new closure (using a @code{ClosureHolder})
3683 */
3684 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3685 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip),
3686 ClosureHolder::add,
3687 ClosureHolder::merge,
3688 ClosureHolder::closure);
3689 }
3690 //where
3691 class ClosureHolder {
3692 List<Type> closure;
3693 final boolean minClosure;
3694 final BiPredicate<Type, Type> shouldSkip;
3695
3696 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3697 this.closure = List.nil();
3698 this.minClosure = minClosure;
3699 this.shouldSkip = shouldSkip;
3700 }
3701
3702 void add(Type type) {
3703 closure = insert(closure, type, shouldSkip);
3704 }
3705
3706 ClosureHolder merge(ClosureHolder other) {
3707 closure = union(closure, other.closure, shouldSkip);
3708 return this;
3709 }
3710
3711 List<Type> closure() {
3712 return minClosure ? closureMin(closure) : closure;
3713 }
3714 }
3715
3716 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym;
3717
3718 /**
3719 * Insert a type in a closure
3720 */
3721 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) {
3722 if (cl.isEmpty()) {
3723 return cl.prepend(t);
3724 } else if (shouldSkip.test(t, cl.head)) {
3725 return cl;
3726 } else if (t.tsym.precedes(cl.head.tsym, this)) {
3727 return cl.prepend(t);
3728 } else {
3729 // t comes after head, or the two are unrelated
3730 return insert(cl.tail, t, shouldSkip).prepend(cl.head);
3731 }
3732 }
3733
3734 public List<Type> insert(List<Type> cl, Type t) {
3735 return insert(cl, t, basicClosureSkip);
3736 }
3737
3738 /**
3739 * Form the union of two closures
3740 */
3741 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) {
3742 if (cl1.isEmpty()) {
3743 return cl2;
3744 } else if (cl2.isEmpty()) {
3745 return cl1;
3746 } else if (shouldSkip.test(cl1.head, cl2.head)) {
3747 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
3748 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3749 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
3750 } else {
3751 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
3752 }
3753 }
3754
3755 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3756 return union(cl1, cl2, basicClosureSkip);
3757 }
3758
3759 /**
3760 * Intersect two closures
3761 */
3762 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3763 if (cl1 == cl2)
3764 return cl1;
3765 if (cl1.isEmpty() || cl2.isEmpty())
3766 return List.nil();
3767 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3768 return intersect(cl1.tail, cl2);
3769 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3770 return intersect(cl1, cl2.tail);
3771 if (isSameType(cl1.head, cl2.head))
3772 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3773 if (cl1.head.tsym == cl2.head.tsym &&
3774 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) {
3775 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3776 Type merge = merge(cl1.head,cl2.head);
3777 return intersect(cl1.tail, cl2.tail).prepend(merge);
3778 }
3779 if (cl1.head.isRaw() || cl2.head.isRaw())
3780 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3781 }
3782 return intersect(cl1.tail, cl2.tail);
3783 }
3784 // where
3785 class TypePair {
3786 final Type t1;
3787 final Type t2;;
3788
3789 TypePair(Type t1, Type t2) {
3790 this.t1 = t1;
3791 this.t2 = t2;
3792 }
3793 @Override
3794 public int hashCode() {
3795 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3796 }
3797 @Override
3798 public boolean equals(Object obj) {
3799 if (!(obj instanceof TypePair))
3800 return false;
3801 TypePair typePair = (TypePair)obj;
3802 return isSameType(t1, typePair.t1)
3803 && isSameType(t2, typePair.t2);
3804 }
3805 }
3806 Set<TypePair> mergeCache = new HashSet<>();
3807 private Type merge(Type c1, Type c2) {
3808 ClassType class1 = (ClassType) c1;
3809 List<Type> act1 = class1.getTypeArguments();
3810 ClassType class2 = (ClassType) c2;
3811 List<Type> act2 = class2.getTypeArguments();
3812 ListBuffer<Type> merged = new ListBuffer<>();
3813 List<Type> typarams = class1.tsym.type.getTypeArguments();
3814
3815 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3816 if (containsType(act1.head, act2.head)) {
3817 merged.append(act1.head);
3818 } else if (containsType(act2.head, act1.head)) {
3819 merged.append(act2.head);
3820 } else {
3821 TypePair pair = new TypePair(c1, c2);
3822 Type m;
3823 if (mergeCache.add(pair)) {
3824 m = new WildcardType(lub(wildUpperBound(act1.head),
3825 wildUpperBound(act2.head)),
3826 BoundKind.EXTENDS,
3827 syms.boundClass);
3828 mergeCache.remove(pair);
3829 } else {
3830 m = new WildcardType(syms.objectType,
3831 BoundKind.UNBOUND,
3832 syms.boundClass);
3833 }
3834 merged.append(m.withTypeVar(typarams.head));
3835 }
3836 act1 = act1.tail;
3837 act2 = act2.tail;
3838 typarams = typarams.tail;
3839 }
3840 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3841 // There is no spec detailing how type annotations are to
3842 // be inherited. So set it to noAnnotations for now
3843 return new ClassType(class1.getEnclosingType(), merged.toList(),
3844 class1.tsym);
3845 }
3846
3847 /**
3848 * Return the minimum type of a closure, a compound type if no
3849 * unique minimum exists.
3850 */
3851 private Type compoundMin(List<Type> cl) {
3852 if (cl.isEmpty()) return syms.objectType;
3853 List<Type> compound = closureMin(cl);
3854 if (compound.isEmpty())
3855 return null;
3856 else if (compound.tail.isEmpty())
3857 return compound.head;
3858 else
3859 return makeIntersectionType(compound);
3860 }
3861
3862 /**
3863 * Return the minimum types of a closure, suitable for computing
3864 * compoundMin or glb.
3865 */
3866 private List<Type> closureMin(List<Type> cl) {
3867 ListBuffer<Type> classes = new ListBuffer<>();
3868 ListBuffer<Type> interfaces = new ListBuffer<>();
3869 Set<Type> toSkip = new HashSet<>();
3870 while (!cl.isEmpty()) {
3871 Type current = cl.head;
3872 boolean keep = !toSkip.contains(current);
3873 if (keep && current.hasTag(TYPEVAR)) {
3874 // skip lower-bounded variables with a subtype in cl.tail
3875 for (Type t : cl.tail) {
3876 if (isSubtypeNoCapture(t, current)) {
3877 keep = false;
3878 break;
3879 }
3880 }
3881 }
3882 if (keep) {
3883 if (current.isInterface())
3884 interfaces.append(current);
3885 else
3886 classes.append(current);
3887 for (Type t : cl.tail) {
3888 // skip supertypes of 'current' in cl.tail
3889 if (isSubtypeNoCapture(current, t))
3890 toSkip.add(t);
3891 }
3892 }
3893 cl = cl.tail;
3894 }
3895 return classes.appendList(interfaces).toList();
3896 }
3897
3898 /**
3899 * Return the least upper bound of list of types. if the lub does
3900 * not exist return null.
3901 */
3902 public Type lub(List<Type> ts) {
3903 return lub(ts.toArray(new Type[ts.length()]));
3904 }
3905
3906 /**
3907 * Return the least upper bound (lub) of set of types. If the lub
3908 * does not exist return the type of null (bottom).
3909 */
3910 public Type lub(Type... ts) {
3911 final int UNKNOWN_BOUND = 0;
3912 final int ARRAY_BOUND = 1;
3913 final int CLASS_BOUND = 2;
3914
3915 int[] kinds = new int[ts.length];
3916
3917 int boundkind = UNKNOWN_BOUND;
3918 for (int i = 0 ; i < ts.length ; i++) {
3919 Type t = ts[i];
3920 switch (t.getTag()) {
3921 case CLASS:
3922 boundkind |= kinds[i] = CLASS_BOUND;
3923 break;
3924 case ARRAY:
3925 boundkind |= kinds[i] = ARRAY_BOUND;
3926 break;
3927 case TYPEVAR:
3928 do {
3929 t = t.getUpperBound();
3930 } while (t.hasTag(TYPEVAR));
3931 if (t.hasTag(ARRAY)) {
3932 boundkind |= kinds[i] = ARRAY_BOUND;
3933 } else {
3934 boundkind |= kinds[i] = CLASS_BOUND;
3935 }
3936 break;
3937 default:
3938 kinds[i] = UNKNOWN_BOUND;
3939 if (t.isPrimitive())
3940 return syms.errType;
3941 }
3942 }
3943 switch (boundkind) {
3944 case 0:
3945 return syms.botType;
3946
3947 case ARRAY_BOUND:
3948 // calculate lub(A[], B[])
3949 Type[] elements = new Type[ts.length];
3950 for (int i = 0 ; i < ts.length ; i++) {
3951 Type elem = elements[i] = elemTypeFun.apply(ts[i]);
3952 if (elem.isPrimitive()) {
3953 // if a primitive type is found, then return
3954 // arraySuperType unless all the types are the
3955 // same
3956 Type first = ts[0];
3957 for (int j = 1 ; j < ts.length ; j++) {
3958 if (!isSameType(first, ts[j])) {
3959 // lub(int[], B[]) is Cloneable & Serializable
3960 return arraySuperType();
3961 }
3962 }
3963 // all the array types are the same, return one
3964 // lub(int[], int[]) is int[]
3965 return first;
3966 }
3967 }
3968 // lub(A[], B[]) is lub(A, B)[]
3969 return new ArrayType(lub(elements), syms.arrayClass);
3970
3971 case CLASS_BOUND:
3972 // calculate lub(A, B)
3973 int startIdx = 0;
3974 for (int i = 0; i < ts.length ; i++) {
3975 Type t = ts[i];
3976 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) {
3977 break;
3978 } else {
3979 startIdx++;
3980 }
3981 }
3982 Assert.check(startIdx < ts.length);
3983 //step 1 - compute erased candidate set (EC)
3984 List<Type> cl = erasedSupertypes(ts[startIdx]);
3985 for (int i = startIdx + 1 ; i < ts.length ; i++) {
3986 Type t = ts[i];
3987 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
3988 cl = intersect(cl, erasedSupertypes(t));
3989 }
3990 //step 2 - compute minimal erased candidate set (MEC)
3991 List<Type> mec = closureMin(cl);
3992 //step 3 - for each element G in MEC, compute lci(Inv(G))
3993 List<Type> candidates = List.nil();
3994 for (Type erasedSupertype : mec) {
3995 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
3996 for (int i = startIdx + 1 ; i < ts.length ; i++) {
3997 Type superType = asSuper(ts[i], erasedSupertype.tsym);
3998 lci = intersect(lci, superType != null ? List.of(superType) : List.nil());
3999 }
4000 candidates = candidates.appendList(lci);
4001 }
4002 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
4003 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
4004 return compoundMin(candidates);
4005
4006 default:
4007 // calculate lub(A, B[])
4008 List<Type> classes = List.of(arraySuperType());
4009 for (int i = 0 ; i < ts.length ; i++) {
4010 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays
4011 classes = classes.prepend(ts[i]);
4012 }
4013 // lub(A, B[]) is lub(A, arraySuperType)
4014 return lub(classes);
4015 }
4016 }
4017 // where
4018 List<Type> erasedSupertypes(Type t) {
4019 ListBuffer<Type> buf = new ListBuffer<>();
4020 for (Type sup : closure(t)) {
4021 if (sup.hasTag(TYPEVAR)) {
4022 buf.append(sup);
4023 } else {
4024 buf.append(erasure(sup));
4025 }
4026 }
4027 return buf.toList();
4028 }
4029
4030 private Type arraySuperType = null;
4031 private Type arraySuperType() {
4032 // initialized lazily to avoid problems during compiler startup
4033 if (arraySuperType == null) {
4034 synchronized (this) {
4035 if (arraySuperType == null) {
4036 // JLS 10.8: all arrays implement Cloneable and Serializable.
4037 arraySuperType = makeIntersectionType(List.of(syms.serializableType,
4038 syms.cloneableType), true);
4039 }
4040 }
4041 }
4042 return arraySuperType;
4043 }
4044 // </editor-fold>
4045
4046 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
4047 public Type glb(List<Type> ts) {
4048 Type t1 = ts.head;
4049 for (Type t2 : ts.tail) {
4050 if (t1.isErroneous())
4051 return t1;
4052 t1 = glb(t1, t2);
4053 }
4054 return t1;
4055 }
4056 //where
4057 public Type glb(Type t, Type s) {
4058 if (s == null)
4059 return t;
4060 else if (t.isPrimitive() || s.isPrimitive())
4061 return syms.errType;
4062 else if (isSubtypeNoCapture(t, s))
4063 return t;
4064 else if (isSubtypeNoCapture(s, t))
4065 return s;
4066
4067 List<Type> closure = union(closure(t), closure(s));
4068 return glbFlattened(closure, t);
4069 }
4070 //where
4071 /**
4072 * Perform glb for a list of non-primitive, non-error, non-compound types;
4073 * redundant elements are removed. Bounds should be ordered according to
4074 * {@link Symbol#precedes(TypeSymbol,Types)}.
4075 *
4076 * @param flatBounds List of type to glb
4077 * @param errT Original type to use if the result is an error type
4078 */
4079 private Type glbFlattened(List<Type> flatBounds, Type errT) {
4080 List<Type> bounds = closureMin(flatBounds);
4081
4082 if (bounds.isEmpty()) { // length == 0
4083 return syms.objectType;
4084 } else if (bounds.tail.isEmpty()) { // length == 1
4085 return bounds.head;
4086 } else { // length > 1
4087 int classCount = 0;
4088 List<Type> cvars = List.nil();
4089 List<Type> lowers = List.nil();
4090 for (Type bound : bounds) {
4091 if (!bound.isInterface()) {
4092 classCount++;
4093 Type lower = cvarLowerBound(bound);
4094 if (bound != lower && !lower.hasTag(BOT)) {
4095 cvars = cvars.append(bound);
4096 lowers = lowers.append(lower);
4097 }
4098 }
4099 }
4100 if (classCount > 1) {
4101 if (lowers.isEmpty()) {
4102 return createErrorType(errT);
4103 } else {
4104 // try again with lower bounds included instead of capture variables
4105 List<Type> newBounds = bounds.diff(cvars).appendList(lowers);
4106 return glb(newBounds);
4107 }
4108 }
4109 }
4110 return makeIntersectionType(bounds);
4111 }
4112 // </editor-fold>
4113
4114 // <editor-fold defaultstate="collapsed" desc="hashCode">
4115 /**
4116 * Compute a hash code on a type.
4117 */
4118 public int hashCode(Type t) {
4119 return hashCode(t, false);
4120 }
4121
4122 public int hashCode(Type t, boolean strict) {
4123 return strict ?
4124 hashCodeStrictVisitor.visit(t) :
4125 hashCodeVisitor.visit(t);
4126 }
4127 // where
4128 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor();
4129 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() {
4130 @Override
4131 public Integer visitTypeVar(TypeVar t, Void ignored) {
4132 return System.identityHashCode(t);
4133 }
4134 };
4135
4136 private static class HashCodeVisitor extends UnaryVisitor<Integer> {
4137 public Integer visitType(Type t, Void ignored) {
4138 return t.getTag().ordinal();
4139 }
4140
4141 @Override
4142 public Integer visitClassType(ClassType t, Void ignored) {
4143 int result = visit(t.getEnclosingType());
4144 result *= 127;
4145 result += t.tsym.flatName().hashCode();
4146 for (Type s : t.getTypeArguments()) {
4147 result *= 127;
4148 result += visit(s);
4149 }
4150 return result;
4151 }
4152
4153 @Override
4154 public Integer visitMethodType(MethodType t, Void ignored) {
4155 int h = METHOD.ordinal();
4156 for (List<Type> thisargs = t.argtypes;
4157 thisargs.tail != null;
4158 thisargs = thisargs.tail)
4159 h = (h << 5) + visit(thisargs.head);
4160 return (h << 5) + visit(t.restype);
4161 }
4162
4163 @Override
4164 public Integer visitWildcardType(WildcardType t, Void ignored) {
4165 int result = t.kind.hashCode();
4166 if (t.type != null) {
4167 result *= 127;
4168 result += visit(t.type);
4169 }
4170 return result;
4171 }
4172
4173 @Override
4174 public Integer visitArrayType(ArrayType t, Void ignored) {
4175 return visit(t.elemtype) + 12;
4176 }
4177
4178 @Override
4179 public Integer visitTypeVar(TypeVar t, Void ignored) {
4180 return System.identityHashCode(t);
4181 }
4182
4183 @Override
4184 public Integer visitUndetVar(UndetVar t, Void ignored) {
4185 return System.identityHashCode(t);
4186 }
4187
4188 @Override
4189 public Integer visitErrorType(ErrorType t, Void ignored) {
4190 return 0;
4191 }
4192 }
4193 // </editor-fold>
4194
4195 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
4196 /**
4197 * Does t have a result that is a subtype of the result type of s,
4198 * suitable for covariant returns? It is assumed that both types
4199 * are (possibly polymorphic) method types. Monomorphic method
4200 * types are handled in the obvious way. Polymorphic method types
4201 * require renaming all type variables of one to corresponding
4202 * type variables in the other, where correspondence is by
4203 * position in the type parameter list. */
4204 public boolean resultSubtype(Type t, Type s, Warner warner) {
4205 List<Type> tvars = t.getTypeArguments();
4206 List<Type> svars = s.getTypeArguments();
4207 Type tres = t.getReturnType();
4208 Type sres = subst(s.getReturnType(), svars, tvars);
4209 return covariantReturnType(tres, sres, warner);
4210 }
4211
4212 /**
4213 * Return-Type-Substitutable.
4214 * @jls 8.4.5 Method Result
4215 */
4216 public boolean returnTypeSubstitutable(Type r1, Type r2) {
4217 if (hasSameArgs(r1, r2))
4218 return resultSubtype(r1, r2, noWarnings);
4219 else
4220 return covariantReturnType(r1.getReturnType(),
4221 erasure(r2.getReturnType()),
4222 noWarnings);
4223 }
4224
4225 public boolean returnTypeSubstitutable(Type r1,
4226 Type r2, Type r2res,
4227 Warner warner) {
4228 if (isSameType(r1.getReturnType(), r2res))
4229 return true;
4230 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
4231 return false;
4232
4233 if (hasSameArgs(r1, r2))
4234 return covariantReturnType(r1.getReturnType(), r2res, warner);
4235 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
4236 return true;
4237 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
4238 return false;
4239 warner.warn(LintCategory.UNCHECKED);
4240 return true;
4241 }
4242
4243 /**
4244 * Is t an appropriate return type in an overrider for a
4245 * method that returns s?
4246 */
4247 public boolean covariantReturnType(Type t, Type s, Warner warner) {
4248 return
4249 isSameType(t, s) ||
4250 !t.isPrimitive() &&
4251 !s.isPrimitive() &&
4252 isAssignable(t, s, warner);
4253 }
4254 // </editor-fold>
4255
4256 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
4257 /**
4258 * Return the class that boxes the given primitive.
4259 */
4260 public ClassSymbol boxedClass(Type t) {
4261 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]);
4262 }
4263
4264 /**
4265 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
4266 */
4267 public Type boxedTypeOrType(Type t) {
4268 return t.isPrimitive() ?
4269 boxedClass(t).type :
4270 t;
4271 }
4272
4273 /**
4274 * Return the primitive type corresponding to a boxed type.
4275 */
4276 public Type unboxedType(Type t) {
4277 for (int i=0; i<syms.boxedName.length; i++) {
4278 Name box = syms.boxedName[i];
4279 if (box != null &&
4280 asSuper(t, syms.enterClass(syms.java_base, box)) != null)
4281 return syms.typeOfTag[i];
4282 }
4283 return Type.noType;
4284 }
4285
4286 /**
4287 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
4288 */
4289 public Type unboxedTypeOrType(Type t) {
4290 Type unboxedType = unboxedType(t);
4291 return unboxedType.hasTag(NONE) ? t : unboxedType;
4292 }
4293 // </editor-fold>
4294
4295 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
4296 /*
4297 * JLS 5.1.10 Capture Conversion:
4298 *
4299 * Let G name a generic type declaration with n formal type
4300 * parameters A1 ... An with corresponding bounds U1 ... Un. There
4301 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
4302 * where, for 1 <= i <= n:
4303 *
4304 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
4305 * Si is a fresh type variable whose upper bound is
4306 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
4307 * type.
4308 *
4309 * + If Ti is a wildcard type argument of the form ? extends Bi,
4310 * then Si is a fresh type variable whose upper bound is
4311 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
4312 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
4313 * a compile-time error if for any two classes (not interfaces)
4314 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
4315 *
4316 * + If Ti is a wildcard type argument of the form ? super Bi,
4317 * then Si is a fresh type variable whose upper bound is
4318 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
4319 *
4320 * + Otherwise, Si = Ti.
4321 *
4322 * Capture conversion on any type other than a parameterized type
4323 * (4.5) acts as an identity conversion (5.1.1). Capture
4324 * conversions never require a special action at run time and
4325 * therefore never throw an exception at run time.
4326 *
4327 * Capture conversion is not applied recursively.
4328 */
4329 /**
4330 * Capture conversion as specified by the JLS.
4331 */
4332
4333 public List<Type> capture(List<Type> ts) {
4334 List<Type> buf = List.nil();
4335 for (Type t : ts) {
4336 buf = buf.prepend(capture(t));
4337 }
4338 return buf.reverse();
4339 }
4340
4341 public Type capture(Type t) {
4342 if (!t.hasTag(CLASS)) {
4343 return t;
4344 }
4345 if (t.getEnclosingType() != Type.noType) {
4346 Type capturedEncl = capture(t.getEnclosingType());
4347 if (capturedEncl != t.getEnclosingType()) {
4348 Type type1 = memberType(capturedEncl, t.tsym);
4349 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
4350 }
4351 }
4352 ClassType cls = (ClassType)t;
4353 if (cls.isRaw() || !cls.isParameterized())
4354 return cls;
4355
4356 ClassType G = (ClassType)cls.asElement().asType();
4357 List<Type> A = G.getTypeArguments();
4358 List<Type> T = cls.getTypeArguments();
4359 List<Type> S = freshTypeVariables(T);
4360
4361 List<Type> currentA = A;
4362 List<Type> currentT = T;
4363 List<Type> currentS = S;
4364 boolean captured = false;
4365 while (!currentA.isEmpty() &&
4366 !currentT.isEmpty() &&
4367 !currentS.isEmpty()) {
4368 if (currentS.head != currentT.head) {
4369 captured = true;
4370 WildcardType Ti = (WildcardType)currentT.head;
4371 Type Ui = currentA.head.getUpperBound();
4372 CapturedType Si = (CapturedType)currentS.head;
4373 if (Ui == null)
4374 Ui = syms.objectType;
4375 switch (Ti.kind) {
4376 case UNBOUND:
4377 Si.setUpperBound( subst(Ui, A, S) );
4378 Si.lower = syms.botType;
4379 break;
4380 case EXTENDS:
4381 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) );
4382 Si.lower = syms.botType;
4383 break;
4384 case SUPER:
4385 Si.setUpperBound( subst(Ui, A, S) );
4386 Si.lower = Ti.getSuperBound();
4387 break;
4388 }
4389 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound();
4390 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower;
4391 if (!Si.getUpperBound().hasTag(ERROR) &&
4392 !Si.lower.hasTag(ERROR) &&
4393 isSameType(tmpBound, tmpLower)) {
4394 currentS.head = Si.getUpperBound();
4395 }
4396 }
4397 currentA = currentA.tail;
4398 currentT = currentT.tail;
4399 currentS = currentS.tail;
4400 }
4401 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
4402 return erasure(t); // some "rare" type involved
4403
4404 if (captured)
4405 return new ClassType(cls.getEnclosingType(), S, cls.tsym,
4406 cls.getMetadata());
4407 else
4408 return t;
4409 }
4410 // where
4411 public List<Type> freshTypeVariables(List<Type> types) {
4412 ListBuffer<Type> result = new ListBuffer<>();
4413 for (Type t : types) {
4414 if (t.hasTag(WILDCARD)) {
4415 Type bound = ((WildcardType)t).getExtendsBound();
4416 if (bound == null)
4417 bound = syms.objectType;
4418 result.append(new CapturedType(capturedName,
4419 syms.noSymbol,
4420 bound,
4421 syms.botType,
4422 (WildcardType)t));
4423 } else {
4424 result.append(t);
4425 }
4426 }
4427 return result.toList();
4428 }
4429 // </editor-fold>
4430
4431 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
4432 private boolean sideCast(Type from, Type to, Warner warn) {
4433 // We are casting from type $from$ to type $to$, which are
4434 // non-final unrelated types. This method
4435 // tries to reject a cast by transferring type parameters
4436 // from $to$ to $from$ by common superinterfaces.
4437 boolean reverse = false;
4438 Type target = to;
4439 if ((to.tsym.flags() & INTERFACE) == 0) {
4440 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4441 reverse = true;
4442 to = from;
4443 from = target;
4444 }
4445 List<Type> commonSupers = superClosure(to, erasure(from));
4446 boolean giveWarning = commonSupers.isEmpty();
4447 // The arguments to the supers could be unified here to
4448 // get a more accurate analysis
4449 while (commonSupers.nonEmpty()) {
4450 Type t1 = asSuper(from, commonSupers.head.tsym);
4451 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
4452 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4453 return false;
4454 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
4455 commonSupers = commonSupers.tail;
4456 }
4457 if (giveWarning && !isReifiable(reverse ? from : to))
4458 warn.warn(LintCategory.UNCHECKED);
4459 return true;
4460 }
4461
4462 private boolean sideCastFinal(Type from, Type to, Warner warn) {
4463 // We are casting from type $from$ to type $to$, which are
4464 // unrelated types one of which is final and the other of
4465 // which is an interface. This method
4466 // tries to reject a cast by transferring type parameters
4467 // from the final class to the interface.
4468 boolean reverse = false;
4469 Type target = to;
4470 if ((to.tsym.flags() & INTERFACE) == 0) {
4471 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4472 reverse = true;
4473 to = from;
4474 from = target;
4475 }
4476 Assert.check((from.tsym.flags() & FINAL) != 0);
4477 Type t1 = asSuper(from, to.tsym);
4478 if (t1 == null) return false;
4479 Type t2 = to;
4480 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4481 return false;
4482 if (!isReifiable(target) &&
4483 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
4484 warn.warn(LintCategory.UNCHECKED);
4485 return true;
4486 }
4487
4488 private boolean giveWarning(Type from, Type to) {
4489 List<Type> bounds = to.isCompound() ?
4490 directSupertypes(to) : List.of(to);
4491 for (Type b : bounds) {
4492 Type subFrom = asSub(from, b.tsym);
4493 if (b.isParameterized() &&
4494 (!(isUnbounded(b) ||
4495 isSubtype(from, b) ||
4496 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
4497 return true;
4498 }
4499 }
4500 return false;
4501 }
4502
4503 private List<Type> superClosure(Type t, Type s) {
4504 List<Type> cl = List.nil();
4505 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
4506 if (isSubtype(s, erasure(l.head))) {
4507 cl = insert(cl, l.head);
4508 } else {
4509 cl = union(cl, superClosure(l.head, s));
4510 }
4511 }
4512 return cl;
4513 }
4514
4515 private boolean containsTypeEquivalent(Type t, Type s) {
4516 return isSameType(t, s) || // shortcut
4517 containsType(t, s) && containsType(s, t);
4518 }
4519
4520 // <editor-fold defaultstate="collapsed" desc="adapt">
4521 /**
4522 * Adapt a type by computing a substitution which maps a source
4523 * type to a target type.
4524 *
4525 * @param source the source type
4526 * @param target the target type
4527 * @param from the type variables of the computed substitution
4528 * @param to the types of the computed substitution.
4529 */
4530 public void adapt(Type source,
4531 Type target,
4532 ListBuffer<Type> from,
4533 ListBuffer<Type> to) throws AdaptFailure {
4534 new Adapter(from, to).adapt(source, target);
4535 }
4536
4537 class Adapter extends SimpleVisitor<Void, Type> {
4538
4539 ListBuffer<Type> from;
4540 ListBuffer<Type> to;
4541 Map<Symbol,Type> mapping;
4542
4543 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
4544 this.from = from;
4545 this.to = to;
4546 mapping = new HashMap<>();
4547 }
4548
4549 public void adapt(Type source, Type target) throws AdaptFailure {
4550 visit(source, target);
4551 List<Type> fromList = from.toList();
4552 List<Type> toList = to.toList();
4553 while (!fromList.isEmpty()) {
4554 Type val = mapping.get(fromList.head.tsym);
4555 if (toList.head != val)
4556 toList.head = val;
4557 fromList = fromList.tail;
4558 toList = toList.tail;
4559 }
4560 }
4561
4562 @Override
4563 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
4564 if (target.hasTag(CLASS))
4565 adaptRecursive(source.allparams(), target.allparams());
4566 return null;
4567 }
4568
4569 @Override
4570 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
4571 if (target.hasTag(ARRAY))
4572 adaptRecursive(elemtype(source), elemtype(target));
4573 return null;
4574 }
4575
4576 @Override
4577 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
4578 if (source.isExtendsBound())
4579 adaptRecursive(wildUpperBound(source), wildUpperBound(target));
4580 else if (source.isSuperBound())
4581 adaptRecursive(wildLowerBound(source), wildLowerBound(target));
4582 return null;
4583 }
4584
4585 @Override
4586 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
4587 // Check to see if there is
4588 // already a mapping for $source$, in which case
4589 // the old mapping will be merged with the new
4590 Type val = mapping.get(source.tsym);
4591 if (val != null) {
4592 if (val.isSuperBound() && target.isSuperBound()) {
4593 val = isSubtype(wildLowerBound(val), wildLowerBound(target))
4594 ? target : val;
4595 } else if (val.isExtendsBound() && target.isExtendsBound()) {
4596 val = isSubtype(wildUpperBound(val), wildUpperBound(target))
4597 ? val : target;
4598 } else if (!isSameType(val, target)) {
4599 throw new AdaptFailure();
4600 }
4601 } else {
4602 val = target;
4603 from.append(source);
4604 to.append(target);
4605 }
4606 mapping.put(source.tsym, val);
4607 return null;
4608 }
4609
4610 @Override
4611 public Void visitType(Type source, Type target) {
4612 return null;
4613 }
4614
4615 private Set<TypePair> cache = new HashSet<>();
4616
4617 private void adaptRecursive(Type source, Type target) {
4618 TypePair pair = new TypePair(source, target);
4619 if (cache.add(pair)) {
4620 try {
4621 visit(source, target);
4622 } finally {
4623 cache.remove(pair);
4624 }
4625 }
4626 }
4627
4628 private void adaptRecursive(List<Type> source, List<Type> target) {
4629 if (source.length() == target.length()) {
4630 while (source.nonEmpty()) {
4631 adaptRecursive(source.head, target.head);
4632 source = source.tail;
4633 target = target.tail;
4634 }
4635 }
4636 }
4637 }
4638
4639 public static class AdaptFailure extends RuntimeException {
4640 static final long serialVersionUID = -7490231548272701566L;
4641 }
4642
4643 private void adaptSelf(Type t,
4644 ListBuffer<Type> from,
4645 ListBuffer<Type> to) {
4646 try {
4647 //if (t.tsym.type != t)
4648 adapt(t.tsym.type, t, from, to);
4649 } catch (AdaptFailure ex) {
4650 // Adapt should never fail calculating a mapping from
4651 // t.tsym.type to t as there can be no merge problem.
4652 throw new AssertionError(ex);
4653 }
4654 }
4655 // </editor-fold>
4656
4657 /**
4658 * Rewrite all type variables (universal quantifiers) in the given
4659 * type to wildcards (existential quantifiers). This is used to
4660 * determine if a cast is allowed. For example, if high is true
4661 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4662 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4663 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4664 * List<Integer>} with a warning.
4665 * @param t a type
4666 * @param high if true return an upper bound; otherwise a lower
4667 * bound
4668 * @param rewriteTypeVars only rewrite captured wildcards if false;
4669 * otherwise rewrite all type variables
4670 * @return the type rewritten with wildcards (existential
4671 * quantifiers) only
4672 */
4673 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4674 return new Rewriter(high, rewriteTypeVars).visit(t);
4675 }
4676
4677 class Rewriter extends UnaryVisitor<Type> {
4678
4679 boolean high;
4680 boolean rewriteTypeVars;
4681
4682 Rewriter(boolean high, boolean rewriteTypeVars) {
4683 this.high = high;
4684 this.rewriteTypeVars = rewriteTypeVars;
4685 }
4686
4687 @Override
4688 public Type visitClassType(ClassType t, Void s) {
4689 ListBuffer<Type> rewritten = new ListBuffer<>();
4690 boolean changed = false;
4691 for (Type arg : t.allparams()) {
4692 Type bound = visit(arg);
4693 if (arg != bound) {
4694 changed = true;
4695 }
4696 rewritten.append(bound);
4697 }
4698 if (changed)
4699 return subst(t.tsym.type,
4700 t.tsym.type.allparams(),
4701 rewritten.toList());
4702 else
4703 return t;
4704 }
4705
4706 public Type visitType(Type t, Void s) {
4707 return t;
4708 }
4709
4710 @Override
4711 public Type visitCapturedType(CapturedType t, Void s) {
4712 Type w_bound = t.wildcard.type;
4713 Type bound = w_bound.contains(t) ?
4714 erasure(w_bound) :
4715 visit(w_bound);
4716 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4717 }
4718
4719 @Override
4720 public Type visitTypeVar(TypeVar t, Void s) {
4721 if (rewriteTypeVars) {
4722 Type bound = t.getUpperBound().contains(t) ?
4723 erasure(t.getUpperBound()) :
4724 visit(t.getUpperBound());
4725 return rewriteAsWildcardType(bound, t, EXTENDS);
4726 } else {
4727 return t;
4728 }
4729 }
4730
4731 @Override
4732 public Type visitWildcardType(WildcardType t, Void s) {
4733 Type bound2 = visit(t.type);
4734 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4735 }
4736
4737 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4738 switch (bk) {
4739 case EXTENDS: return high ?
4740 makeExtendsWildcard(B(bound), formal) :
4741 makeExtendsWildcard(syms.objectType, formal);
4742 case SUPER: return high ?
4743 makeSuperWildcard(syms.botType, formal) :
4744 makeSuperWildcard(B(bound), formal);
4745 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4746 default:
4747 Assert.error("Invalid bound kind " + bk);
4748 return null;
4749 }
4750 }
4751
4752 Type B(Type t) {
4753 while (t.hasTag(WILDCARD)) {
4754 WildcardType w = (WildcardType)t;
4755 t = high ?
4756 w.getExtendsBound() :
4757 w.getSuperBound();
4758 if (t == null) {
4759 t = high ? syms.objectType : syms.botType;
4760 }
4761 }
4762 return t;
4763 }
4764 }
4765
4766
4767 /**
4768 * Create a wildcard with the given upper (extends) bound; create
4769 * an unbounded wildcard if bound is Object.
4770 *
4771 * @param bound the upper bound
4772 * @param formal the formal type parameter that will be
4773 * substituted by the wildcard
4774 */
4775 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4776 if (bound == syms.objectType) {
4777 return new WildcardType(syms.objectType,
4778 BoundKind.UNBOUND,
4779 syms.boundClass,
4780 formal);
4781 } else {
4782 return new WildcardType(bound,
4783 BoundKind.EXTENDS,
4784 syms.boundClass,
4785 formal);
4786 }
4787 }
4788
4789 /**
4790 * Create a wildcard with the given lower (super) bound; create an
4791 * unbounded wildcard if bound is bottom (type of {@code null}).
4792 *
4793 * @param bound the lower bound
4794 * @param formal the formal type parameter that will be
4795 * substituted by the wildcard
4796 */
4797 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4798 if (bound.hasTag(BOT)) {
4799 return new WildcardType(syms.objectType,
4800 BoundKind.UNBOUND,
4801 syms.boundClass,
4802 formal);
4803 } else {
4804 return new WildcardType(bound,
4805 BoundKind.SUPER,
4806 syms.boundClass,
4807 formal);
4808 }
4809 }
4810
4811 /**
4812 * A wrapper for a type that allows use in sets.
4813 */
4814 public static class UniqueType {
4815 public final Type type;
4816 final Types types;
4817
4818 public UniqueType(Type type, Types types) {
4819 this.type = type;
4820 this.types = types;
4821 }
4822
4823 public int hashCode() {
4824 return types.hashCode(type);
4825 }
4826
4827 public boolean equals(Object obj) {
4828 return (obj instanceof UniqueType) &&
4829 types.isSameType(type, ((UniqueType)obj).type);
4830 }
4831
4832 public String toString() {
4833 return type.toString();
4834 }
4835
4836 }
4837 // </editor-fold>
4838
4839 // <editor-fold defaultstate="collapsed" desc="Visitors">
4840 /**
4841 * A default visitor for types. All visitor methods except
4842 * visitType are implemented by delegating to visitType. Concrete
4843 * subclasses must provide an implementation of visitType and can
4844 * override other methods as needed.
4845 *
4846 * @param <R> the return type of the operation implemented by this
4847 * visitor; use Void if no return type is needed.
4848 * @param <S> the type of the second argument (the first being the
4849 * type itself) of the operation implemented by this visitor; use
4850 * Void if a second argument is not needed.
4851 */
4852 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4853 final public R visit(Type t, S s) { return t.accept(this, s); }
4854 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4855 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4856 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4857 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4858 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4859 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); }
4860 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4861 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4862 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4863 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4864 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4865 }
4866
4867 /**
4868 * A default visitor for symbols. All visitor methods except
4869 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4870 * subclasses must provide an implementation of visitSymbol and can
4871 * override other methods as needed.
4872 *
4873 * @param <R> the return type of the operation implemented by this
4874 * visitor; use Void if no return type is needed.
4875 * @param <S> the type of the second argument (the first being the
4876 * symbol itself) of the operation implemented by this visitor; use
4877 * Void if a second argument is not needed.
4878 */
4879 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4880 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
4881 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4882 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4883 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4884 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4885 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4886 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4887 }
4888
4889 /**
4890 * A <em>simple</em> visitor for types. This visitor is simple as
4891 * captured wildcards, for-all types (generic methods), and
4892 * undetermined type variables (part of inference) are hidden.
4893 * Captured wildcards are hidden by treating them as type
4894 * variables and the rest are hidden by visiting their qtypes.
4895 *
4896 * @param <R> the return type of the operation implemented by this
4897 * visitor; use Void if no return type is needed.
4898 * @param <S> the type of the second argument (the first being the
4899 * type itself) of the operation implemented by this visitor; use
4900 * Void if a second argument is not needed.
4901 */
4902 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4903 @Override
4904 public R visitCapturedType(CapturedType t, S s) {
4905 return visitTypeVar(t, s);
4906 }
4907 @Override
4908 public R visitForAll(ForAll t, S s) {
4909 return visit(t.qtype, s);
4910 }
4911 @Override
4912 public R visitUndetVar(UndetVar t, S s) {
4913 return visit(t.qtype, s);
4914 }
4915 }
4916
4917 /**
4918 * A plain relation on types. That is a 2-ary function on the
4919 * form Type × Type → Boolean.
4920 * <!-- In plain text: Type x Type -> Boolean -->
4921 */
4922 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4923
4924 /**
4925 * A convenience visitor for implementing operations that only
4926 * require one argument (the type itself), that is, unary
4927 * operations.
4928 *
4929 * @param <R> the return type of the operation implemented by this
4930 * visitor; use Void if no return type is needed.
4931 */
4932 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4933 final public R visit(Type t) { return t.accept(this, null); }
4934 }
4935
4936 /**
4937 * A visitor for implementing a mapping from types to types. The
4938 * default behavior of this class is to implement the identity
4939 * mapping (mapping a type to itself). This can be overridden in
4940 * subclasses.
4941 *
4942 * @param <S> the type of the second argument (the first being the
4943 * type itself) of this mapping; use Void if a second argument is
4944 * not needed.
4945 */
4946 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4947 final public Type visit(Type t) { return t.accept(this, null); }
4948 public Type visitType(Type t, S s) { return t; }
4949 }
4950
4951 /**
4952 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}.
4953 * This class implements the functional interface {@code Function}, that allows it to be used
4954 * fluently in stream-like processing.
4955 */
4956 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> {
4957 @Override
4958 public Type apply(Type type) { return visit(type); }
4959
4960 List<Type> visit(List<Type> ts, S s) {
4961 return ts.map(t -> visit(t, s));
4962 }
4963
4964 @Override
4965 public Type visitCapturedType(CapturedType t, S s) {
4966 return visitTypeVar(t, s);
4967 }
4968 }
4969 // </editor-fold>
4970
4971
4972 // <editor-fold defaultstate="collapsed" desc="Annotation support">
4973
4974 public RetentionPolicy getRetention(Attribute.Compound a) {
4975 return getRetention(a.type.tsym);
4976 }
4977
4978 public RetentionPolicy getRetention(TypeSymbol sym) {
4979 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
4980 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
4981 if (c != null) {
4982 Attribute value = c.member(names.value);
4983 if (value != null && value instanceof Attribute.Enum) {
4984 Name levelName = ((Attribute.Enum)value).value.name;
4985 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
4986 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
4987 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
4988 else ;// /* fail soft */ throw new AssertionError(levelName);
4989 }
4990 }
4991 return vis;
4992 }
4993 // </editor-fold>
4994
4995 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
4996
4997 public static abstract class SignatureGenerator {
4998
4999 public static class InvalidSignatureException extends RuntimeException {
5000 private static final long serialVersionUID = 0;
5001
5002 private final transient Type type;
5003
5004 InvalidSignatureException(Type type) {
5005 this.type = type;
5006 }
5007
5008 public Type type() {
5009 return type;
5010 }
5011 }
5012
5013 private final Types types;
5014
5015 protected abstract void append(char ch);
5016 protected abstract void append(byte[] ba);
5017 protected abstract void append(Name name);
5018 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
5019
5020 protected SignatureGenerator(Types types) {
5021 this.types = types;
5022 }
5023
5024 protected void reportIllegalSignature(Type t) {
5025 throw new InvalidSignatureException(t);
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 reportIllegalSignature(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 reportIllegalSignature(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 public void assembleSig(List<Type> types) {
5178 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
5179 assembleSig(ts.head);
5180 }
5181 }
5182 }
5183
5184 public Type constantType(LoadableConstant c) {
5185 switch (c.poolTag()) {
5186 case ClassFile.CONSTANT_Class:
5187 return syms.classType;
5188 case ClassFile.CONSTANT_String:
5189 return syms.stringType;
5190 case ClassFile.CONSTANT_Integer:
5191 return syms.intType;
5192 case ClassFile.CONSTANT_Float:
5193 return syms.floatType;
5194 case ClassFile.CONSTANT_Long:
5195 return syms.longType;
5196 case ClassFile.CONSTANT_Double:
5197 return syms.doubleType;
5198 case ClassFile.CONSTANT_MethodHandle:
5199 return syms.methodHandleType;
5200 case ClassFile.CONSTANT_MethodType:
5201 return syms.methodTypeType;
5202 case ClassFile.CONSTANT_Dynamic:
5203 return ((DynamicVarSymbol)c).type;
5204 default:
5205 throw new AssertionError("Not a loadable constant: " + c.poolTag());
5206 }
5207 }
5208 // </editor-fold>
5209
5210 public void newRound() {
5211 descCache._map.clear();
5212 isDerivedRawCache.clear();
5213 implCache._map.clear();
5214 membersCache._map.clear();
5215 closureCache.clear();
5216 }
5217 }