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src/share/classes/com/sun/tools/javac/code/Types.java@7a4717f3ea7b
src/share/classes/com/sun/tools/javac/code/Types.java
Thu, 22 Aug 2013 10:22:44 +0100
- author
- vromero
- date
- Thu, 22 Aug 2013 10:22:44 +0100
- changeset 1973
- 7a4717f3ea7b
- parent 1919
- 3155e77d2676
- child 2000
- 4a6acc42c3a1
- permissions
- -rw-r--r--
8022316: Generic throws, overriding and method reference
Reviewed-by: jjg, mcimadamore
1 /*
2 * Copyright (c) 2003, 2013, 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 */
26 package com.sun.tools.javac.code;
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.Set;
34 import java.util.WeakHashMap;
36 import javax.tools.JavaFileObject;
38 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
39 import com.sun.tools.javac.code.Lint.LintCategory;
40 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
41 import com.sun.tools.javac.comp.AttrContext;
42 import com.sun.tools.javac.comp.Check;
43 import com.sun.tools.javac.comp.Enter;
44 import com.sun.tools.javac.comp.Env;
45 import com.sun.tools.javac.jvm.ClassReader;
46 import com.sun.tools.javac.util.*;
47 import static com.sun.tools.javac.code.BoundKind.*;
48 import static com.sun.tools.javac.code.Flags.*;
49 import static com.sun.tools.javac.code.Scope.*;
50 import static com.sun.tools.javac.code.Symbol.*;
51 import static com.sun.tools.javac.code.Type.*;
52 import static com.sun.tools.javac.code.TypeTag.*;
53 import static com.sun.tools.javac.jvm.ClassFile.externalize;
54 import static com.sun.tools.javac.util.ListBuffer.lb;
56 /**
57 * Utility class containing various operations on types.
58 *
59 * <p>Unless other names are more illustrative, the following naming
60 * conventions should be observed in this file:
61 *
62 * <dl>
63 * <dt>t</dt>
64 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
65 * <dt>s</dt>
66 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
67 * <dt>ts</dt>
68 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
69 * <dt>ss</dt>
70 * <dd>A second list of types should be named ss.</dd>
71 * </dl>
72 *
73 * <p><b>This is NOT part of any supported API.
74 * If you write code that depends on this, you do so at your own risk.
75 * This code and its internal interfaces are subject to change or
76 * deletion without notice.</b>
77 */
78 public class Types {
79 protected static final Context.Key<Types> typesKey =
80 new Context.Key<Types>();
82 final Symtab syms;
83 final JavacMessages messages;
84 final Names names;
85 final boolean allowBoxing;
86 final boolean allowCovariantReturns;
87 final boolean allowObjectToPrimitiveCast;
88 final boolean allowDefaultMethods;
89 final ClassReader reader;
90 final Check chk;
91 final Enter enter;
92 JCDiagnostic.Factory diags;
93 List<Warner> warnStack = List.nil();
94 final Name capturedName;
95 private final FunctionDescriptorLookupError functionDescriptorLookupError;
97 public final Warner noWarnings;
99 // <editor-fold defaultstate="collapsed" desc="Instantiating">
100 public static Types instance(Context context) {
101 Types instance = context.get(typesKey);
102 if (instance == null)
103 instance = new Types(context);
104 return instance;
105 }
107 protected Types(Context context) {
108 context.put(typesKey, this);
109 syms = Symtab.instance(context);
110 names = Names.instance(context);
111 Source source = Source.instance(context);
112 allowBoxing = source.allowBoxing();
113 allowCovariantReturns = source.allowCovariantReturns();
114 allowObjectToPrimitiveCast = source.allowObjectToPrimitiveCast();
115 allowDefaultMethods = source.allowDefaultMethods();
116 reader = ClassReader.instance(context);
117 chk = Check.instance(context);
118 enter = Enter.instance(context);
119 capturedName = names.fromString("<captured wildcard>");
120 messages = JavacMessages.instance(context);
121 diags = JCDiagnostic.Factory.instance(context);
122 functionDescriptorLookupError = new FunctionDescriptorLookupError();
123 noWarnings = new Warner(null);
124 }
125 // </editor-fold>
127 // <editor-fold defaultstate="collapsed" desc="upperBound">
128 /**
129 * The "rvalue conversion".<br>
130 * The upper bound of most types is the type
131 * itself. Wildcards, on the other hand have upper
132 * and lower bounds.
133 * @param t a type
134 * @return the upper bound of the given type
135 */
136 public Type upperBound(Type t) {
137 return upperBound.visit(t).unannotatedType();
138 }
139 // where
140 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
142 @Override
143 public Type visitWildcardType(WildcardType t, Void ignored) {
144 if (t.isSuperBound())
145 return t.bound == null ? syms.objectType : t.bound.bound;
146 else
147 return visit(t.type);
148 }
150 @Override
151 public Type visitCapturedType(CapturedType t, Void ignored) {
152 return visit(t.bound);
153 }
154 };
155 // </editor-fold>
157 // <editor-fold defaultstate="collapsed" desc="lowerBound">
158 /**
159 * The "lvalue conversion".<br>
160 * The lower bound of most types is the type
161 * itself. Wildcards, on the other hand have upper
162 * and lower bounds.
163 * @param t a type
164 * @return the lower bound of the given type
165 */
166 public Type lowerBound(Type t) {
167 return lowerBound.visit(t);
168 }
169 // where
170 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
172 @Override
173 public Type visitWildcardType(WildcardType t, Void ignored) {
174 return t.isExtendsBound() ? syms.botType : visit(t.type);
175 }
177 @Override
178 public Type visitCapturedType(CapturedType t, Void ignored) {
179 return visit(t.getLowerBound());
180 }
181 };
182 // </editor-fold>
184 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
185 /**
186 * Checks that all the arguments to a class are unbounded
187 * wildcards or something else that doesn't make any restrictions
188 * on the arguments. If a class isUnbounded, a raw super- or
189 * subclass can be cast to it without a warning.
190 * @param t a type
191 * @return true iff the given type is unbounded or raw
192 */
193 public boolean isUnbounded(Type t) {
194 return isUnbounded.visit(t);
195 }
196 // where
197 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
199 public Boolean visitType(Type t, Void ignored) {
200 return true;
201 }
203 @Override
204 public Boolean visitClassType(ClassType t, Void ignored) {
205 List<Type> parms = t.tsym.type.allparams();
206 List<Type> args = t.allparams();
207 while (parms.nonEmpty()) {
208 WildcardType unb = new WildcardType(syms.objectType,
209 BoundKind.UNBOUND,
210 syms.boundClass,
211 (TypeVar)parms.head.unannotatedType());
212 if (!containsType(args.head, unb))
213 return false;
214 parms = parms.tail;
215 args = args.tail;
216 }
217 return true;
218 }
219 };
220 // </editor-fold>
222 // <editor-fold defaultstate="collapsed" desc="asSub">
223 /**
224 * Return the least specific subtype of t that starts with symbol
225 * sym. If none exists, return null. The least specific subtype
226 * is determined as follows:
227 *
228 * <p>If there is exactly one parameterized instance of sym that is a
229 * subtype of t, that parameterized instance is returned.<br>
230 * Otherwise, if the plain type or raw type `sym' is a subtype of
231 * type t, the type `sym' itself is returned. Otherwise, null is
232 * returned.
233 */
234 public Type asSub(Type t, Symbol sym) {
235 return asSub.visit(t, sym);
236 }
237 // where
238 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
240 public Type visitType(Type t, Symbol sym) {
241 return null;
242 }
244 @Override
245 public Type visitClassType(ClassType t, Symbol sym) {
246 if (t.tsym == sym)
247 return t;
248 Type base = asSuper(sym.type, t.tsym);
249 if (base == null)
250 return null;
251 ListBuffer<Type> from = new ListBuffer<Type>();
252 ListBuffer<Type> to = new ListBuffer<Type>();
253 try {
254 adapt(base, t, from, to);
255 } catch (AdaptFailure ex) {
256 return null;
257 }
258 Type res = subst(sym.type, from.toList(), to.toList());
259 if (!isSubtype(res, t))
260 return null;
261 ListBuffer<Type> openVars = new ListBuffer<Type>();
262 for (List<Type> l = sym.type.allparams();
263 l.nonEmpty(); l = l.tail)
264 if (res.contains(l.head) && !t.contains(l.head))
265 openVars.append(l.head);
266 if (openVars.nonEmpty()) {
267 if (t.isRaw()) {
268 // The subtype of a raw type is raw
269 res = erasure(res);
270 } else {
271 // Unbound type arguments default to ?
272 List<Type> opens = openVars.toList();
273 ListBuffer<Type> qs = new ListBuffer<Type>();
274 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
275 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head.unannotatedType()));
276 }
277 res = subst(res, opens, qs.toList());
278 }
279 }
280 return res;
281 }
283 @Override
284 public Type visitErrorType(ErrorType t, Symbol sym) {
285 return t;
286 }
287 };
288 // </editor-fold>
290 // <editor-fold defaultstate="collapsed" desc="isConvertible">
291 /**
292 * Is t a subtype of or convertible via boxing/unboxing
293 * conversion to s?
294 */
295 public boolean isConvertible(Type t, Type s, Warner warn) {
296 if (t.hasTag(ERROR)) {
297 return true;
298 }
299 boolean tPrimitive = t.isPrimitive();
300 boolean sPrimitive = s.isPrimitive();
301 if (tPrimitive == sPrimitive) {
302 return isSubtypeUnchecked(t, s, warn);
303 }
304 if (!allowBoxing) return false;
305 return tPrimitive
306 ? isSubtype(boxedClass(t).type, s)
307 : isSubtype(unboxedType(t), s);
308 }
310 /**
311 * Is t a subtype of or convertiable via boxing/unboxing
312 * convertions to s?
313 */
314 public boolean isConvertible(Type t, Type s) {
315 return isConvertible(t, s, noWarnings);
316 }
317 // </editor-fold>
319 // <editor-fold defaultstate="collapsed" desc="findSam">
321 /**
322 * Exception used to report a function descriptor lookup failure. The exception
323 * wraps a diagnostic that can be used to generate more details error
324 * messages.
325 */
326 public static class FunctionDescriptorLookupError extends RuntimeException {
327 private static final long serialVersionUID = 0;
329 JCDiagnostic diagnostic;
331 FunctionDescriptorLookupError() {
332 this.diagnostic = null;
333 }
335 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
336 this.diagnostic = diag;
337 return this;
338 }
340 public JCDiagnostic getDiagnostic() {
341 return diagnostic;
342 }
343 }
345 /**
346 * A cache that keeps track of function descriptors associated with given
347 * functional interfaces.
348 */
349 class DescriptorCache {
351 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<TypeSymbol, Entry>();
353 class FunctionDescriptor {
354 Symbol descSym;
356 FunctionDescriptor(Symbol descSym) {
357 this.descSym = descSym;
358 }
360 public Symbol getSymbol() {
361 return descSym;
362 }
364 public Type getType(Type site) {
365 site = removeWildcards(site);
366 if (!chk.checkValidGenericType(site)) {
367 //if the inferred functional interface type is not well-formed,
368 //or if it's not a subtype of the original target, issue an error
369 throw failure(diags.fragment("no.suitable.functional.intf.inst", site));
370 }
371 return memberType(site, descSym);
372 }
373 }
375 class Entry {
376 final FunctionDescriptor cachedDescRes;
377 final int prevMark;
379 public Entry(FunctionDescriptor cachedDescRes,
380 int prevMark) {
381 this.cachedDescRes = cachedDescRes;
382 this.prevMark = prevMark;
383 }
385 boolean matches(int mark) {
386 return this.prevMark == mark;
387 }
388 }
390 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
391 Entry e = _map.get(origin);
392 CompoundScope members = membersClosure(origin.type, false);
393 if (e == null ||
394 !e.matches(members.getMark())) {
395 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
396 _map.put(origin, new Entry(descRes, members.getMark()));
397 return descRes;
398 }
399 else {
400 return e.cachedDescRes;
401 }
402 }
404 /**
405 * Compute the function descriptor associated with a given functional interface
406 */
407 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin,
408 CompoundScope membersCache) throws FunctionDescriptorLookupError {
409 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0) {
410 //t must be an interface
411 throw failure("not.a.functional.intf", origin);
412 }
414 final ListBuffer<Symbol> abstracts = ListBuffer.lb();
415 for (Symbol sym : membersCache.getElements(new DescriptorFilter(origin))) {
416 Type mtype = memberType(origin.type, sym);
417 if (abstracts.isEmpty() ||
418 (sym.name == abstracts.first().name &&
419 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
420 abstracts.append(sym);
421 } else {
422 //the target method(s) should be the only abstract members of t
423 throw failure("not.a.functional.intf.1", origin,
424 diags.fragment("incompatible.abstracts", Kinds.kindName(origin), origin));
425 }
426 }
427 if (abstracts.isEmpty()) {
428 //t must define a suitable non-generic method
429 throw failure("not.a.functional.intf.1", origin,
430 diags.fragment("no.abstracts", Kinds.kindName(origin), origin));
431 } else if (abstracts.size() == 1) {
432 return new FunctionDescriptor(abstracts.first());
433 } else { // size > 1
434 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
435 if (descRes == null) {
436 //we can get here if the functional interface is ill-formed
437 ListBuffer<JCDiagnostic> descriptors = ListBuffer.lb();
438 for (Symbol desc : abstracts) {
439 String key = desc.type.getThrownTypes().nonEmpty() ?
440 "descriptor.throws" : "descriptor";
441 descriptors.append(diags.fragment(key, desc.name,
442 desc.type.getParameterTypes(),
443 desc.type.getReturnType(),
444 desc.type.getThrownTypes()));
445 }
446 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
447 new JCDiagnostic.MultilineDiagnostic(diags.fragment("incompatible.descs.in.functional.intf",
448 Kinds.kindName(origin), origin), descriptors.toList());
449 throw failure(incompatibleDescriptors);
450 }
451 return descRes;
452 }
453 }
455 /**
456 * Compute a synthetic type for the target descriptor given a list
457 * of override-equivalent methods in the functional interface type.
458 * The resulting method type is a method type that is override-equivalent
459 * and return-type substitutable with each method in the original list.
460 */
461 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
462 //pick argument types - simply take the signature that is a
463 //subsignature of all other signatures in the list (as per JLS 8.4.2)
464 List<Symbol> mostSpecific = List.nil();
465 outer: for (Symbol msym1 : methodSyms) {
466 Type mt1 = memberType(origin.type, msym1);
467 for (Symbol msym2 : methodSyms) {
468 Type mt2 = memberType(origin.type, msym2);
469 if (!isSubSignature(mt1, mt2)) {
470 continue outer;
471 }
472 }
473 mostSpecific = mostSpecific.prepend(msym1);
474 }
475 if (mostSpecific.isEmpty()) {
476 return null;
477 }
480 //pick return types - this is done in two phases: (i) first, the most
481 //specific return type is chosen using strict subtyping; if this fails,
482 //a second attempt is made using return type substitutability (see JLS 8.4.5)
483 boolean phase2 = false;
484 Symbol bestSoFar = null;
485 while (bestSoFar == null) {
486 outer: for (Symbol msym1 : mostSpecific) {
487 Type mt1 = memberType(origin.type, msym1);
488 for (Symbol msym2 : methodSyms) {
489 Type mt2 = memberType(origin.type, msym2);
490 if (phase2 ?
491 !returnTypeSubstitutable(mt1, mt2) :
492 !isSubtypeInternal(mt1.getReturnType(), mt2.getReturnType())) {
493 continue outer;
494 }
495 }
496 bestSoFar = msym1;
497 }
498 if (phase2) {
499 break;
500 } else {
501 phase2 = true;
502 }
503 }
504 if (bestSoFar == null) return null;
506 //merge thrown types - form the intersection of all the thrown types in
507 //all the signatures in the list
508 boolean toErase = !bestSoFar.type.hasTag(FORALL);
509 List<Type> thrown = null;
510 Type mt1 = memberType(origin.type, bestSoFar);
511 for (Symbol msym2 : methodSyms) {
512 Type mt2 = memberType(origin.type, msym2);
513 List<Type> thrown_mt2 = mt2.getThrownTypes();
514 if (toErase) {
515 thrown_mt2 = erasure(thrown_mt2);
516 } else {
517 /* If bestSoFar is generic then all the methods are generic.
518 * The opposite is not true: a non generic method can override
519 * a generic method (raw override) so it's safe to cast mt1 and
520 * mt2 to ForAll.
521 */
522 ForAll fa1 = (ForAll)mt1;
523 ForAll fa2 = (ForAll)mt2;
524 thrown_mt2 = subst(thrown_mt2, fa2.tvars, fa1.tvars);
525 }
526 thrown = (thrown == null) ?
527 thrown_mt2 :
528 chk.intersect(thrown_mt2, thrown);
529 }
531 final List<Type> thrown1 = thrown;
532 return new FunctionDescriptor(bestSoFar) {
533 @Override
534 public Type getType(Type origin) {
535 Type mt = memberType(origin, getSymbol());
536 return createMethodTypeWithThrown(mt, thrown1);
537 }
538 };
539 }
541 boolean isSubtypeInternal(Type s, Type t) {
542 return (s.isPrimitive() && t.isPrimitive()) ?
543 isSameType(t, s) :
544 isSubtype(s, t);
545 }
547 FunctionDescriptorLookupError failure(String msg, Object... args) {
548 return failure(diags.fragment(msg, args));
549 }
551 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
552 return functionDescriptorLookupError.setMessage(diag);
553 }
554 }
556 private DescriptorCache descCache = new DescriptorCache();
558 /**
559 * Find the method descriptor associated to this class symbol - if the
560 * symbol 'origin' is not a functional interface, an exception is thrown.
561 */
562 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
563 return descCache.get(origin).getSymbol();
564 }
566 /**
567 * Find the type of the method descriptor associated to this class symbol -
568 * if the symbol 'origin' is not a functional interface, an exception is thrown.
569 */
570 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
571 return descCache.get(origin.tsym).getType(origin);
572 }
574 /**
575 * Is given type a functional interface?
576 */
577 public boolean isFunctionalInterface(TypeSymbol tsym) {
578 try {
579 findDescriptorSymbol(tsym);
580 return true;
581 } catch (FunctionDescriptorLookupError ex) {
582 return false;
583 }
584 }
586 public boolean isFunctionalInterface(Type site) {
587 try {
588 findDescriptorType(site);
589 return true;
590 } catch (FunctionDescriptorLookupError ex) {
591 return false;
592 }
593 }
595 public Type removeWildcards(Type site) {
596 Type capturedSite = capture(site);
597 if (capturedSite != site) {
598 Type formalInterface = site.tsym.type;
599 ListBuffer<Type> typeargs = ListBuffer.lb();
600 List<Type> actualTypeargs = site.getTypeArguments();
601 List<Type> capturedTypeargs = capturedSite.getTypeArguments();
602 //simply replace the wildcards with its bound
603 for (Type t : formalInterface.getTypeArguments()) {
604 if (actualTypeargs.head.hasTag(WILDCARD)) {
605 WildcardType wt = (WildcardType)actualTypeargs.head.unannotatedType();
606 Type bound;
607 switch (wt.kind) {
608 case EXTENDS:
609 case UNBOUND:
610 CapturedType capVar = (CapturedType)capturedTypeargs.head.unannotatedType();
611 //use declared bound if it doesn't depend on formal type-args
612 bound = capVar.bound.containsAny(capturedSite.getTypeArguments()) ?
613 wt.type : capVar.bound;
614 break;
615 default:
616 bound = wt.type;
617 }
618 typeargs.append(bound);
619 } else {
620 typeargs.append(actualTypeargs.head);
621 }
622 actualTypeargs = actualTypeargs.tail;
623 capturedTypeargs = capturedTypeargs.tail;
624 }
625 return subst(formalInterface, formalInterface.getTypeArguments(), typeargs.toList());
626 } else {
627 return site;
628 }
629 }
631 /**
632 * Create a symbol for a class that implements a given functional interface
633 * and overrides its functional descriptor. This routine is used for two
634 * main purposes: (i) checking well-formedness of a functional interface;
635 * (ii) perform functional interface bridge calculation.
636 */
637 public ClassSymbol makeFunctionalInterfaceClass(Env<AttrContext> env, Name name, List<Type> targets, long cflags) {
638 if (targets.isEmpty() || !isFunctionalInterface(targets.head)) {
639 return null;
640 }
641 Symbol descSym = findDescriptorSymbol(targets.head.tsym);
642 Type descType = findDescriptorType(targets.head);
643 ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass());
644 csym.completer = null;
645 csym.members_field = new Scope(csym);
646 MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym);
647 csym.members_field.enter(instDescSym);
648 Type.ClassType ctype = new Type.ClassType(Type.noType, List.<Type>nil(), csym);
649 ctype.supertype_field = syms.objectType;
650 ctype.interfaces_field = targets;
651 csym.type = ctype;
652 csym.sourcefile = ((ClassSymbol)csym.owner).sourcefile;
653 return csym;
654 }
656 /**
657 * Find the minimal set of methods that are overridden by the functional
658 * descriptor in 'origin'. All returned methods are assumed to have different
659 * erased signatures.
660 */
661 public List<Symbol> functionalInterfaceBridges(TypeSymbol origin) {
662 Assert.check(isFunctionalInterface(origin));
663 Symbol descSym = findDescriptorSymbol(origin);
664 CompoundScope members = membersClosure(origin.type, false);
665 ListBuffer<Symbol> overridden = ListBuffer.lb();
666 outer: for (Symbol m2 : members.getElementsByName(descSym.name, bridgeFilter)) {
667 if (m2 == descSym) continue;
668 else if (descSym.overrides(m2, origin, Types.this, false)) {
669 for (Symbol m3 : overridden) {
670 if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) ||
671 (m3.overrides(m2, origin, Types.this, false) &&
672 (pendingBridges((ClassSymbol)origin, m3.enclClass()) ||
673 (((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) {
674 continue outer;
675 }
676 }
677 overridden.add(m2);
678 }
679 }
680 return overridden.toList();
681 }
682 //where
683 private Filter<Symbol> bridgeFilter = new Filter<Symbol>() {
684 public boolean accepts(Symbol t) {
685 return t.kind == Kinds.MTH &&
686 t.name != names.init &&
687 t.name != names.clinit &&
688 (t.flags() & SYNTHETIC) == 0;
689 }
690 };
691 private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) {
692 //a symbol will be completed from a classfile if (a) symbol has
693 //an associated file object with CLASS kind and (b) the symbol has
694 //not been entered
695 if (origin.classfile != null &&
696 origin.classfile.getKind() == JavaFileObject.Kind.CLASS &&
697 enter.getEnv(origin) == null) {
698 return false;
699 }
700 if (origin == s) {
701 return true;
702 }
703 for (Type t : interfaces(origin.type)) {
704 if (pendingBridges((ClassSymbol)t.tsym, s)) {
705 return true;
706 }
707 }
708 return false;
709 }
710 // </editor-fold>
712 /**
713 * Scope filter used to skip methods that should be ignored (such as methods
714 * overridden by j.l.Object) during function interface conversion interface check
715 */
716 class DescriptorFilter implements Filter<Symbol> {
718 TypeSymbol origin;
720 DescriptorFilter(TypeSymbol origin) {
721 this.origin = origin;
722 }
724 @Override
725 public boolean accepts(Symbol sym) {
726 return sym.kind == Kinds.MTH &&
727 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
728 !overridesObjectMethod(origin, sym) &&
729 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
730 }
731 };
733 // <editor-fold defaultstate="collapsed" desc="isSubtype">
734 /**
735 * Is t an unchecked subtype of s?
736 */
737 public boolean isSubtypeUnchecked(Type t, Type s) {
738 return isSubtypeUnchecked(t, s, noWarnings);
739 }
740 /**
741 * Is t an unchecked subtype of s?
742 */
743 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
744 boolean result = isSubtypeUncheckedInternal(t, s, warn);
745 if (result) {
746 checkUnsafeVarargsConversion(t, s, warn);
747 }
748 return result;
749 }
750 //where
751 private boolean isSubtypeUncheckedInternal(Type t, Type s, Warner warn) {
752 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
753 t = t.unannotatedType();
754 s = s.unannotatedType();
755 if (((ArrayType)t).elemtype.isPrimitive()) {
756 return isSameType(elemtype(t), elemtype(s));
757 } else {
758 return isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
759 }
760 } else if (isSubtype(t, s)) {
761 return true;
762 } else if (t.hasTag(TYPEVAR)) {
763 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
764 } else if (!s.isRaw()) {
765 Type t2 = asSuper(t, s.tsym);
766 if (t2 != null && t2.isRaw()) {
767 if (isReifiable(s)) {
768 warn.silentWarn(LintCategory.UNCHECKED);
769 } else {
770 warn.warn(LintCategory.UNCHECKED);
771 }
772 return true;
773 }
774 }
775 return false;
776 }
778 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
779 if (!t.hasTag(ARRAY) || isReifiable(t)) {
780 return;
781 }
782 t = t.unannotatedType();
783 s = s.unannotatedType();
784 ArrayType from = (ArrayType)t;
785 boolean shouldWarn = false;
786 switch (s.getTag()) {
787 case ARRAY:
788 ArrayType to = (ArrayType)s;
789 shouldWarn = from.isVarargs() &&
790 !to.isVarargs() &&
791 !isReifiable(from);
792 break;
793 case CLASS:
794 shouldWarn = from.isVarargs();
795 break;
796 }
797 if (shouldWarn) {
798 warn.warn(LintCategory.VARARGS);
799 }
800 }
802 /**
803 * Is t a subtype of s?<br>
804 * (not defined for Method and ForAll types)
805 */
806 final public boolean isSubtype(Type t, Type s) {
807 return isSubtype(t, s, true);
808 }
809 final public boolean isSubtypeNoCapture(Type t, Type s) {
810 return isSubtype(t, s, false);
811 }
812 public boolean isSubtype(Type t, Type s, boolean capture) {
813 if (t == s)
814 return true;
816 t = t.unannotatedType();
817 s = s.unannotatedType();
819 if (t == s)
820 return true;
822 if (s.isPartial())
823 return isSuperType(s, t);
825 if (s.isCompound()) {
826 for (Type s2 : interfaces(s).prepend(supertype(s))) {
827 if (!isSubtype(t, s2, capture))
828 return false;
829 }
830 return true;
831 }
833 Type lower = lowerBound(s);
834 if (s != lower)
835 return isSubtype(capture ? capture(t) : t, lower, false);
837 return isSubtype.visit(capture ? capture(t) : t, s);
838 }
839 // where
840 private TypeRelation isSubtype = new TypeRelation()
841 {
842 @Override
843 public Boolean visitType(Type t, Type s) {
844 switch (t.getTag()) {
845 case BYTE:
846 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
847 case CHAR:
848 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
849 case SHORT: case INT: case LONG:
850 case FLOAT: case DOUBLE:
851 return t.getTag().isSubRangeOf(s.getTag());
852 case BOOLEAN: case VOID:
853 return t.hasTag(s.getTag());
854 case TYPEVAR:
855 return isSubtypeNoCapture(t.getUpperBound(), s);
856 case BOT:
857 return
858 s.hasTag(BOT) || s.hasTag(CLASS) ||
859 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
860 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
861 case NONE:
862 return false;
863 default:
864 throw new AssertionError("isSubtype " + t.getTag());
865 }
866 }
868 private Set<TypePair> cache = new HashSet<TypePair>();
870 private boolean containsTypeRecursive(Type t, Type s) {
871 TypePair pair = new TypePair(t, s);
872 if (cache.add(pair)) {
873 try {
874 return containsType(t.getTypeArguments(),
875 s.getTypeArguments());
876 } finally {
877 cache.remove(pair);
878 }
879 } else {
880 return containsType(t.getTypeArguments(),
881 rewriteSupers(s).getTypeArguments());
882 }
883 }
885 private Type rewriteSupers(Type t) {
886 if (!t.isParameterized())
887 return t;
888 ListBuffer<Type> from = lb();
889 ListBuffer<Type> to = lb();
890 adaptSelf(t, from, to);
891 if (from.isEmpty())
892 return t;
893 ListBuffer<Type> rewrite = lb();
894 boolean changed = false;
895 for (Type orig : to.toList()) {
896 Type s = rewriteSupers(orig);
897 if (s.isSuperBound() && !s.isExtendsBound()) {
898 s = new WildcardType(syms.objectType,
899 BoundKind.UNBOUND,
900 syms.boundClass);
901 changed = true;
902 } else if (s != orig) {
903 s = new WildcardType(upperBound(s),
904 BoundKind.EXTENDS,
905 syms.boundClass);
906 changed = true;
907 }
908 rewrite.append(s);
909 }
910 if (changed)
911 return subst(t.tsym.type, from.toList(), rewrite.toList());
912 else
913 return t;
914 }
916 @Override
917 public Boolean visitClassType(ClassType t, Type s) {
918 Type sup = asSuper(t, s.tsym);
919 return sup != null
920 && sup.tsym == s.tsym
921 // You're not allowed to write
922 // Vector<Object> vec = new Vector<String>();
923 // But with wildcards you can write
924 // Vector<? extends Object> vec = new Vector<String>();
925 // which means that subtype checking must be done
926 // here instead of same-type checking (via containsType).
927 && (!s.isParameterized() || containsTypeRecursive(s, sup))
928 && isSubtypeNoCapture(sup.getEnclosingType(),
929 s.getEnclosingType());
930 }
932 @Override
933 public Boolean visitArrayType(ArrayType t, Type s) {
934 if (s.hasTag(ARRAY)) {
935 if (t.elemtype.isPrimitive())
936 return isSameType(t.elemtype, elemtype(s));
937 else
938 return isSubtypeNoCapture(t.elemtype, elemtype(s));
939 }
941 if (s.hasTag(CLASS)) {
942 Name sname = s.tsym.getQualifiedName();
943 return sname == names.java_lang_Object
944 || sname == names.java_lang_Cloneable
945 || sname == names.java_io_Serializable;
946 }
948 return false;
949 }
951 @Override
952 public Boolean visitUndetVar(UndetVar t, Type s) {
953 //todo: test against origin needed? or replace with substitution?
954 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
955 return true;
956 } else if (s.hasTag(BOT)) {
957 //if 's' is 'null' there's no instantiated type U for which
958 //U <: s (but 'null' itself, which is not a valid type)
959 return false;
960 }
962 t.addBound(InferenceBound.UPPER, s, Types.this);
963 return true;
964 }
966 @Override
967 public Boolean visitErrorType(ErrorType t, Type s) {
968 return true;
969 }
970 };
972 /**
973 * Is t a subtype of every type in given list `ts'?<br>
974 * (not defined for Method and ForAll types)<br>
975 * Allows unchecked conversions.
976 */
977 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
978 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
979 if (!isSubtypeUnchecked(t, l.head, warn))
980 return false;
981 return true;
982 }
984 /**
985 * Are corresponding elements of ts subtypes of ss? If lists are
986 * of different length, return false.
987 */
988 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
989 while (ts.tail != null && ss.tail != null
990 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
991 isSubtype(ts.head, ss.head)) {
992 ts = ts.tail;
993 ss = ss.tail;
994 }
995 return ts.tail == null && ss.tail == null;
996 /*inlined: ts.isEmpty() && ss.isEmpty();*/
997 }
999 /**
1000 * Are corresponding elements of ts subtypes of ss, allowing
1001 * unchecked conversions? If lists are of different length,
1002 * return false.
1003 **/
1004 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
1005 while (ts.tail != null && ss.tail != null
1006 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1007 isSubtypeUnchecked(ts.head, ss.head, warn)) {
1008 ts = ts.tail;
1009 ss = ss.tail;
1010 }
1011 return ts.tail == null && ss.tail == null;
1012 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1013 }
1014 // </editor-fold>
1016 // <editor-fold defaultstate="collapsed" desc="isSuperType">
1017 /**
1018 * Is t a supertype of s?
1019 */
1020 public boolean isSuperType(Type t, Type s) {
1021 switch (t.getTag()) {
1022 case ERROR:
1023 return true;
1024 case UNDETVAR: {
1025 UndetVar undet = (UndetVar)t;
1026 if (t == s ||
1027 undet.qtype == s ||
1028 s.hasTag(ERROR) ||
1029 s.hasTag(BOT)) {
1030 return true;
1031 }
1032 undet.addBound(InferenceBound.LOWER, s, this);
1033 return true;
1034 }
1035 default:
1036 return isSubtype(s, t);
1037 }
1038 }
1039 // </editor-fold>
1041 // <editor-fold defaultstate="collapsed" desc="isSameType">
1042 /**
1043 * Are corresponding elements of the lists the same type? If
1044 * lists are of different length, return false.
1045 */
1046 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
1047 return isSameTypes(ts, ss, false);
1048 }
1049 public boolean isSameTypes(List<Type> ts, List<Type> ss, boolean strict) {
1050 while (ts.tail != null && ss.tail != null
1051 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1052 isSameType(ts.head, ss.head, strict)) {
1053 ts = ts.tail;
1054 ss = ss.tail;
1055 }
1056 return ts.tail == null && ss.tail == null;
1057 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1058 }
1060 /**
1061 * A polymorphic signature method (JLS SE 7, 8.4.1) is a method that
1062 * (i) is declared in the java.lang.invoke.MethodHandle class, (ii) takes
1063 * a single variable arity parameter (iii) whose declared type is Object[],
1064 * (iv) has a return type of Object and (v) is native.
1065 */
1066 public boolean isSignaturePolymorphic(MethodSymbol msym) {
1067 List<Type> argtypes = msym.type.getParameterTypes();
1068 return (msym.flags_field & NATIVE) != 0 &&
1069 msym.owner == syms.methodHandleType.tsym &&
1070 argtypes.tail.tail == null &&
1071 argtypes.head.hasTag(TypeTag.ARRAY) &&
1072 msym.type.getReturnType().tsym == syms.objectType.tsym &&
1073 ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym;
1074 }
1076 /**
1077 * Is t the same type as s?
1078 */
1079 public boolean isSameType(Type t, Type s) {
1080 return isSameType(t, s, false);
1081 }
1082 public boolean isSameType(Type t, Type s, boolean strict) {
1083 return strict ?
1084 isSameTypeStrict.visit(t, s) :
1085 isSameTypeLoose.visit(t, s);
1086 }
1087 public boolean isSameAnnotatedType(Type t, Type s) {
1088 return isSameAnnotatedType.visit(t, s);
1089 }
1090 // where
1091 abstract class SameTypeVisitor extends TypeRelation {
1093 public Boolean visitType(Type t, Type s) {
1094 if (t == s)
1095 return true;
1097 if (s.isPartial())
1098 return visit(s, t);
1100 switch (t.getTag()) {
1101 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1102 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
1103 return t.hasTag(s.getTag());
1104 case TYPEVAR: {
1105 if (s.hasTag(TYPEVAR)) {
1106 //type-substitution does not preserve type-var types
1107 //check that type var symbols and bounds are indeed the same
1108 return sameTypeVars((TypeVar)t.unannotatedType(), (TypeVar)s.unannotatedType());
1109 }
1110 else {
1111 //special case for s == ? super X, where upper(s) = u
1112 //check that u == t, where u has been set by Type.withTypeVar
1113 return s.isSuperBound() &&
1114 !s.isExtendsBound() &&
1115 visit(t, upperBound(s));
1116 }
1117 }
1118 default:
1119 throw new AssertionError("isSameType " + t.getTag());
1120 }
1121 }
1123 abstract boolean sameTypeVars(TypeVar tv1, TypeVar tv2);
1125 @Override
1126 public Boolean visitWildcardType(WildcardType t, Type s) {
1127 if (s.isPartial())
1128 return visit(s, t);
1129 else
1130 return false;
1131 }
1133 @Override
1134 public Boolean visitClassType(ClassType t, Type s) {
1135 if (t == s)
1136 return true;
1138 if (s.isPartial())
1139 return visit(s, t);
1141 if (s.isSuperBound() && !s.isExtendsBound())
1142 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
1144 if (t.isCompound() && s.isCompound()) {
1145 if (!visit(supertype(t), supertype(s)))
1146 return false;
1148 HashSet<UniqueType> set = new HashSet<UniqueType>();
1149 for (Type x : interfaces(t))
1150 set.add(new UniqueType(x.unannotatedType(), Types.this));
1151 for (Type x : interfaces(s)) {
1152 if (!set.remove(new UniqueType(x.unannotatedType(), Types.this)))
1153 return false;
1154 }
1155 return (set.isEmpty());
1156 }
1157 return t.tsym == s.tsym
1158 && visit(t.getEnclosingType(), s.getEnclosingType())
1159 && containsTypes(t.getTypeArguments(), s.getTypeArguments());
1160 }
1162 abstract protected boolean containsTypes(List<Type> ts1, List<Type> ts2);
1164 @Override
1165 public Boolean visitArrayType(ArrayType t, Type s) {
1166 if (t == s)
1167 return true;
1169 if (s.isPartial())
1170 return visit(s, t);
1172 return s.hasTag(ARRAY)
1173 && containsTypeEquivalent(t.elemtype, elemtype(s));
1174 }
1176 @Override
1177 public Boolean visitMethodType(MethodType t, Type s) {
1178 // isSameType for methods does not take thrown
1179 // exceptions into account!
1180 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
1181 }
1183 @Override
1184 public Boolean visitPackageType(PackageType t, Type s) {
1185 return t == s;
1186 }
1188 @Override
1189 public Boolean visitForAll(ForAll t, Type s) {
1190 if (!s.hasTag(FORALL)) {
1191 return false;
1192 }
1194 ForAll forAll = (ForAll)s;
1195 return hasSameBounds(t, forAll)
1196 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1197 }
1199 @Override
1200 public Boolean visitUndetVar(UndetVar t, Type s) {
1201 if (s.hasTag(WILDCARD)) {
1202 // FIXME, this might be leftovers from before capture conversion
1203 return false;
1204 }
1206 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
1207 return true;
1208 }
1210 t.addBound(InferenceBound.EQ, s, Types.this);
1212 return true;
1213 }
1215 @Override
1216 public Boolean visitErrorType(ErrorType t, Type s) {
1217 return true;
1218 }
1219 }
1221 /**
1222 * Standard type-equality relation - type variables are considered
1223 * equals if they share the same type symbol.
1224 */
1225 TypeRelation isSameTypeLoose = new LooseSameTypeVisitor();
1227 private class LooseSameTypeVisitor extends SameTypeVisitor {
1228 @Override
1229 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1230 return tv1.tsym == tv2.tsym && visit(tv1.getUpperBound(), tv2.getUpperBound());
1231 }
1232 @Override
1233 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1234 return containsTypeEquivalent(ts1, ts2);
1235 }
1236 };
1238 /**
1239 * Strict type-equality relation - type variables are considered
1240 * equals if they share the same object identity.
1241 */
1242 TypeRelation isSameTypeStrict = new SameTypeVisitor() {
1243 @Override
1244 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1245 return tv1 == tv2;
1246 }
1247 @Override
1248 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1249 return isSameTypes(ts1, ts2, true);
1250 }
1252 @Override
1253 public Boolean visitWildcardType(WildcardType t, Type s) {
1254 if (!s.hasTag(WILDCARD)) {
1255 return false;
1256 } else {
1257 WildcardType t2 = (WildcardType)s.unannotatedType();
1258 return t.kind == t2.kind &&
1259 isSameType(t.type, t2.type, true);
1260 }
1261 }
1262 };
1264 /**
1265 * A version of LooseSameTypeVisitor that takes AnnotatedTypes
1266 * into account.
1267 */
1268 TypeRelation isSameAnnotatedType = new LooseSameTypeVisitor() {
1269 @Override
1270 public Boolean visitAnnotatedType(AnnotatedType t, Type s) {
1271 if (!s.isAnnotated())
1272 return false;
1273 if (!t.getAnnotationMirrors().containsAll(s.getAnnotationMirrors()))
1274 return false;
1275 if (!s.getAnnotationMirrors().containsAll(t.getAnnotationMirrors()))
1276 return false;
1277 return visit(t.underlyingType, s);
1278 }
1279 };
1280 // </editor-fold>
1282 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1283 public boolean containedBy(Type t, Type s) {
1284 switch (t.getTag()) {
1285 case UNDETVAR:
1286 if (s.hasTag(WILDCARD)) {
1287 UndetVar undetvar = (UndetVar)t;
1288 WildcardType wt = (WildcardType)s.unannotatedType();
1289 switch(wt.kind) {
1290 case UNBOUND: //similar to ? extends Object
1291 case EXTENDS: {
1292 Type bound = upperBound(s);
1293 undetvar.addBound(InferenceBound.UPPER, bound, this);
1294 break;
1295 }
1296 case SUPER: {
1297 Type bound = lowerBound(s);
1298 undetvar.addBound(InferenceBound.LOWER, bound, this);
1299 break;
1300 }
1301 }
1302 return true;
1303 } else {
1304 return isSameType(t, s);
1305 }
1306 case ERROR:
1307 return true;
1308 default:
1309 return containsType(s, t);
1310 }
1311 }
1313 boolean containsType(List<Type> ts, List<Type> ss) {
1314 while (ts.nonEmpty() && ss.nonEmpty()
1315 && containsType(ts.head, ss.head)) {
1316 ts = ts.tail;
1317 ss = ss.tail;
1318 }
1319 return ts.isEmpty() && ss.isEmpty();
1320 }
1322 /**
1323 * Check if t contains s.
1324 *
1325 * <p>T contains S if:
1326 *
1327 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1328 *
1329 * <p>This relation is only used by ClassType.isSubtype(), that
1330 * is,
1331 *
1332 * <p>{@code C<S> <: C<T> if T contains S.}
1333 *
1334 * <p>Because of F-bounds, this relation can lead to infinite
1335 * recursion. Thus we must somehow break that recursion. Notice
1336 * that containsType() is only called from ClassType.isSubtype().
1337 * Since the arguments have already been checked against their
1338 * bounds, we know:
1339 *
1340 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1341 *
1342 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1343 *
1344 * @param t a type
1345 * @param s a type
1346 */
1347 public boolean containsType(Type t, Type s) {
1348 return containsType.visit(t, s);
1349 }
1350 // where
1351 private TypeRelation containsType = new TypeRelation() {
1353 private Type U(Type t) {
1354 while (t.hasTag(WILDCARD)) {
1355 WildcardType w = (WildcardType)t.unannotatedType();
1356 if (w.isSuperBound())
1357 return w.bound == null ? syms.objectType : w.bound.bound;
1358 else
1359 t = w.type;
1360 }
1361 return t;
1362 }
1364 private Type L(Type t) {
1365 while (t.hasTag(WILDCARD)) {
1366 WildcardType w = (WildcardType)t.unannotatedType();
1367 if (w.isExtendsBound())
1368 return syms.botType;
1369 else
1370 t = w.type;
1371 }
1372 return t;
1373 }
1375 public Boolean visitType(Type t, Type s) {
1376 if (s.isPartial())
1377 return containedBy(s, t);
1378 else
1379 return isSameType(t, s);
1380 }
1382 // void debugContainsType(WildcardType t, Type s) {
1383 // System.err.println();
1384 // System.err.format(" does %s contain %s?%n", t, s);
1385 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1386 // upperBound(s), s, t, U(t),
1387 // t.isSuperBound()
1388 // || isSubtypeNoCapture(upperBound(s), U(t)));
1389 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1390 // L(t), t, s, lowerBound(s),
1391 // t.isExtendsBound()
1392 // || isSubtypeNoCapture(L(t), lowerBound(s)));
1393 // System.err.println();
1394 // }
1396 @Override
1397 public Boolean visitWildcardType(WildcardType t, Type s) {
1398 if (s.isPartial())
1399 return containedBy(s, t);
1400 else {
1401 // debugContainsType(t, s);
1402 return isSameWildcard(t, s)
1403 || isCaptureOf(s, t)
1404 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
1405 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
1406 }
1407 }
1409 @Override
1410 public Boolean visitUndetVar(UndetVar t, Type s) {
1411 if (!s.hasTag(WILDCARD)) {
1412 return isSameType(t, s);
1413 } else {
1414 return false;
1415 }
1416 }
1418 @Override
1419 public Boolean visitErrorType(ErrorType t, Type s) {
1420 return true;
1421 }
1422 };
1424 public boolean isCaptureOf(Type s, WildcardType t) {
1425 if (!s.hasTag(TYPEVAR) || !((TypeVar)s.unannotatedType()).isCaptured())
1426 return false;
1427 return isSameWildcard(t, ((CapturedType)s.unannotatedType()).wildcard);
1428 }
1430 public boolean isSameWildcard(WildcardType t, Type s) {
1431 if (!s.hasTag(WILDCARD))
1432 return false;
1433 WildcardType w = (WildcardType)s.unannotatedType();
1434 return w.kind == t.kind && w.type == t.type;
1435 }
1437 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1438 while (ts.nonEmpty() && ss.nonEmpty()
1439 && containsTypeEquivalent(ts.head, ss.head)) {
1440 ts = ts.tail;
1441 ss = ss.tail;
1442 }
1443 return ts.isEmpty() && ss.isEmpty();
1444 }
1445 // </editor-fold>
1447 /**
1448 * Can t and s be compared for equality? Any primitive ==
1449 * primitive or primitive == object comparisons here are an error.
1450 * Unboxing and correct primitive == primitive comparisons are
1451 * already dealt with in Attr.visitBinary.
1452 *
1453 */
1454 public boolean isEqualityComparable(Type s, Type t, Warner warn) {
1455 if (t.isNumeric() && s.isNumeric())
1456 return true;
1458 boolean tPrimitive = t.isPrimitive();
1459 boolean sPrimitive = s.isPrimitive();
1460 if (!tPrimitive && !sPrimitive) {
1461 return isCastable(s, t, warn) || isCastable(t, s, warn);
1462 } else {
1463 return false;
1464 }
1465 }
1467 // <editor-fold defaultstate="collapsed" desc="isCastable">
1468 public boolean isCastable(Type t, Type s) {
1469 return isCastable(t, s, noWarnings);
1470 }
1472 /**
1473 * Is t is castable to s?<br>
1474 * s is assumed to be an erased type.<br>
1475 * (not defined for Method and ForAll types).
1476 */
1477 public boolean isCastable(Type t, Type s, Warner warn) {
1478 if (t == s)
1479 return true;
1481 if (t.isPrimitive() != s.isPrimitive())
1482 return allowBoxing && (
1483 isConvertible(t, s, warn)
1484 || (allowObjectToPrimitiveCast &&
1485 s.isPrimitive() &&
1486 isSubtype(boxedClass(s).type, t)));
1487 if (warn != warnStack.head) {
1488 try {
1489 warnStack = warnStack.prepend(warn);
1490 checkUnsafeVarargsConversion(t, s, warn);
1491 return isCastable.visit(t,s);
1492 } finally {
1493 warnStack = warnStack.tail;
1494 }
1495 } else {
1496 return isCastable.visit(t,s);
1497 }
1498 }
1499 // where
1500 private TypeRelation isCastable = new TypeRelation() {
1502 public Boolean visitType(Type t, Type s) {
1503 if (s.hasTag(ERROR))
1504 return true;
1506 switch (t.getTag()) {
1507 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1508 case DOUBLE:
1509 return s.isNumeric();
1510 case BOOLEAN:
1511 return s.hasTag(BOOLEAN);
1512 case VOID:
1513 return false;
1514 case BOT:
1515 return isSubtype(t, s);
1516 default:
1517 throw new AssertionError();
1518 }
1519 }
1521 @Override
1522 public Boolean visitWildcardType(WildcardType t, Type s) {
1523 return isCastable(upperBound(t), s, warnStack.head);
1524 }
1526 @Override
1527 public Boolean visitClassType(ClassType t, Type s) {
1528 if (s.hasTag(ERROR) || s.hasTag(BOT))
1529 return true;
1531 if (s.hasTag(TYPEVAR)) {
1532 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1533 warnStack.head.warn(LintCategory.UNCHECKED);
1534 return true;
1535 } else {
1536 return false;
1537 }
1538 }
1540 if (t.isCompound() || s.isCompound()) {
1541 return !t.isCompound() ?
1542 visitIntersectionType((IntersectionClassType)s.unannotatedType(), t, true) :
1543 visitIntersectionType((IntersectionClassType)t.unannotatedType(), s, false);
1544 }
1546 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) {
1547 boolean upcast;
1548 if ((upcast = isSubtype(erasure(t), erasure(s)))
1549 || isSubtype(erasure(s), erasure(t))) {
1550 if (!upcast && s.hasTag(ARRAY)) {
1551 if (!isReifiable(s))
1552 warnStack.head.warn(LintCategory.UNCHECKED);
1553 return true;
1554 } else if (s.isRaw()) {
1555 return true;
1556 } else if (t.isRaw()) {
1557 if (!isUnbounded(s))
1558 warnStack.head.warn(LintCategory.UNCHECKED);
1559 return true;
1560 }
1561 // Assume |a| <: |b|
1562 final Type a = upcast ? t : s;
1563 final Type b = upcast ? s : t;
1564 final boolean HIGH = true;
1565 final boolean LOW = false;
1566 final boolean DONT_REWRITE_TYPEVARS = false;
1567 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1568 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1569 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1570 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1571 Type lowSub = asSub(bLow, aLow.tsym);
1572 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1573 if (highSub == null) {
1574 final boolean REWRITE_TYPEVARS = true;
1575 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1576 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1577 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1578 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1579 lowSub = asSub(bLow, aLow.tsym);
1580 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1581 }
1582 if (highSub != null) {
1583 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1584 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1585 }
1586 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1587 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1588 && !disjointTypes(aLow.allparams(), highSub.allparams())
1589 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1590 if (upcast ? giveWarning(a, b) :
1591 giveWarning(b, a))
1592 warnStack.head.warn(LintCategory.UNCHECKED);
1593 return true;
1594 }
1595 }
1596 if (isReifiable(s))
1597 return isSubtypeUnchecked(a, b);
1598 else
1599 return isSubtypeUnchecked(a, b, warnStack.head);
1600 }
1602 // Sidecast
1603 if (s.hasTag(CLASS)) {
1604 if ((s.tsym.flags() & INTERFACE) != 0) {
1605 return ((t.tsym.flags() & FINAL) == 0)
1606 ? sideCast(t, s, warnStack.head)
1607 : sideCastFinal(t, s, warnStack.head);
1608 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1609 return ((s.tsym.flags() & FINAL) == 0)
1610 ? sideCast(t, s, warnStack.head)
1611 : sideCastFinal(t, s, warnStack.head);
1612 } else {
1613 // unrelated class types
1614 return false;
1615 }
1616 }
1617 }
1618 return false;
1619 }
1621 boolean visitIntersectionType(IntersectionClassType ict, Type s, boolean reverse) {
1622 Warner warn = noWarnings;
1623 for (Type c : ict.getComponents()) {
1624 warn.clear();
1625 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1626 return false;
1627 }
1628 if (warn.hasLint(LintCategory.UNCHECKED))
1629 warnStack.head.warn(LintCategory.UNCHECKED);
1630 return true;
1631 }
1633 @Override
1634 public Boolean visitArrayType(ArrayType t, Type s) {
1635 switch (s.getTag()) {
1636 case ERROR:
1637 case BOT:
1638 return true;
1639 case TYPEVAR:
1640 if (isCastable(s, t, noWarnings)) {
1641 warnStack.head.warn(LintCategory.UNCHECKED);
1642 return true;
1643 } else {
1644 return false;
1645 }
1646 case CLASS:
1647 return isSubtype(t, s);
1648 case ARRAY:
1649 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1650 return elemtype(t).hasTag(elemtype(s).getTag());
1651 } else {
1652 return visit(elemtype(t), elemtype(s));
1653 }
1654 default:
1655 return false;
1656 }
1657 }
1659 @Override
1660 public Boolean visitTypeVar(TypeVar t, Type s) {
1661 switch (s.getTag()) {
1662 case ERROR:
1663 case BOT:
1664 return true;
1665 case TYPEVAR:
1666 if (isSubtype(t, s)) {
1667 return true;
1668 } else if (isCastable(t.bound, s, noWarnings)) {
1669 warnStack.head.warn(LintCategory.UNCHECKED);
1670 return true;
1671 } else {
1672 return false;
1673 }
1674 default:
1675 return isCastable(t.bound, s, warnStack.head);
1676 }
1677 }
1679 @Override
1680 public Boolean visitErrorType(ErrorType t, Type s) {
1681 return true;
1682 }
1683 };
1684 // </editor-fold>
1686 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1687 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1688 while (ts.tail != null && ss.tail != null) {
1689 if (disjointType(ts.head, ss.head)) return true;
1690 ts = ts.tail;
1691 ss = ss.tail;
1692 }
1693 return false;
1694 }
1696 /**
1697 * Two types or wildcards are considered disjoint if it can be
1698 * proven that no type can be contained in both. It is
1699 * conservative in that it is allowed to say that two types are
1700 * not disjoint, even though they actually are.
1701 *
1702 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1703 * {@code X} and {@code Y} are not disjoint.
1704 */
1705 public boolean disjointType(Type t, Type s) {
1706 return disjointType.visit(t, s);
1707 }
1708 // where
1709 private TypeRelation disjointType = new TypeRelation() {
1711 private Set<TypePair> cache = new HashSet<TypePair>();
1713 @Override
1714 public Boolean visitType(Type t, Type s) {
1715 if (s.hasTag(WILDCARD))
1716 return visit(s, t);
1717 else
1718 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1719 }
1721 private boolean isCastableRecursive(Type t, Type s) {
1722 TypePair pair = new TypePair(t, s);
1723 if (cache.add(pair)) {
1724 try {
1725 return Types.this.isCastable(t, s);
1726 } finally {
1727 cache.remove(pair);
1728 }
1729 } else {
1730 return true;
1731 }
1732 }
1734 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1735 TypePair pair = new TypePair(t, s);
1736 if (cache.add(pair)) {
1737 try {
1738 return Types.this.notSoftSubtype(t, s);
1739 } finally {
1740 cache.remove(pair);
1741 }
1742 } else {
1743 return false;
1744 }
1745 }
1747 @Override
1748 public Boolean visitWildcardType(WildcardType t, Type s) {
1749 if (t.isUnbound())
1750 return false;
1752 if (!s.hasTag(WILDCARD)) {
1753 if (t.isExtendsBound())
1754 return notSoftSubtypeRecursive(s, t.type);
1755 else
1756 return notSoftSubtypeRecursive(t.type, s);
1757 }
1759 if (s.isUnbound())
1760 return false;
1762 if (t.isExtendsBound()) {
1763 if (s.isExtendsBound())
1764 return !isCastableRecursive(t.type, upperBound(s));
1765 else if (s.isSuperBound())
1766 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1767 } else if (t.isSuperBound()) {
1768 if (s.isExtendsBound())
1769 return notSoftSubtypeRecursive(t.type, upperBound(s));
1770 }
1771 return false;
1772 }
1773 };
1774 // </editor-fold>
1776 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1777 /**
1778 * Returns the lower bounds of the formals of a method.
1779 */
1780 public List<Type> lowerBoundArgtypes(Type t) {
1781 return lowerBounds(t.getParameterTypes());
1782 }
1783 public List<Type> lowerBounds(List<Type> ts) {
1784 return map(ts, lowerBoundMapping);
1785 }
1786 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1787 public Type apply(Type t) {
1788 return lowerBound(t);
1789 }
1790 };
1791 // </editor-fold>
1793 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1794 /**
1795 * This relation answers the question: is impossible that
1796 * something of type `t' can be a subtype of `s'? This is
1797 * different from the question "is `t' not a subtype of `s'?"
1798 * when type variables are involved: Integer is not a subtype of T
1799 * where {@code <T extends Number>} but it is not true that Integer cannot
1800 * possibly be a subtype of T.
1801 */
1802 public boolean notSoftSubtype(Type t, Type s) {
1803 if (t == s) return false;
1804 if (t.hasTag(TYPEVAR)) {
1805 TypeVar tv = (TypeVar) t;
1806 return !isCastable(tv.bound,
1807 relaxBound(s),
1808 noWarnings);
1809 }
1810 if (!s.hasTag(WILDCARD))
1811 s = upperBound(s);
1813 return !isSubtype(t, relaxBound(s));
1814 }
1816 private Type relaxBound(Type t) {
1817 if (t.hasTag(TYPEVAR)) {
1818 while (t.hasTag(TYPEVAR))
1819 t = t.getUpperBound();
1820 t = rewriteQuantifiers(t, true, true);
1821 }
1822 return t;
1823 }
1824 // </editor-fold>
1826 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1827 public boolean isReifiable(Type t) {
1828 return isReifiable.visit(t);
1829 }
1830 // where
1831 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1833 public Boolean visitType(Type t, Void ignored) {
1834 return true;
1835 }
1837 @Override
1838 public Boolean visitClassType(ClassType t, Void ignored) {
1839 if (t.isCompound())
1840 return false;
1841 else {
1842 if (!t.isParameterized())
1843 return true;
1845 for (Type param : t.allparams()) {
1846 if (!param.isUnbound())
1847 return false;
1848 }
1849 return true;
1850 }
1851 }
1853 @Override
1854 public Boolean visitArrayType(ArrayType t, Void ignored) {
1855 return visit(t.elemtype);
1856 }
1858 @Override
1859 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1860 return false;
1861 }
1862 };
1863 // </editor-fold>
1865 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1866 public boolean isArray(Type t) {
1867 while (t.hasTag(WILDCARD))
1868 t = upperBound(t);
1869 return t.hasTag(ARRAY);
1870 }
1872 /**
1873 * The element type of an array.
1874 */
1875 public Type elemtype(Type t) {
1876 switch (t.getTag()) {
1877 case WILDCARD:
1878 return elemtype(upperBound(t));
1879 case ARRAY:
1880 t = t.unannotatedType();
1881 return ((ArrayType)t).elemtype;
1882 case FORALL:
1883 return elemtype(((ForAll)t).qtype);
1884 case ERROR:
1885 return t;
1886 default:
1887 return null;
1888 }
1889 }
1891 public Type elemtypeOrType(Type t) {
1892 Type elemtype = elemtype(t);
1893 return elemtype != null ?
1894 elemtype :
1895 t;
1896 }
1898 /**
1899 * Mapping to take element type of an arraytype
1900 */
1901 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1902 public Type apply(Type t) { return elemtype(t); }
1903 };
1905 /**
1906 * The number of dimensions of an array type.
1907 */
1908 public int dimensions(Type t) {
1909 int result = 0;
1910 while (t.hasTag(ARRAY)) {
1911 result++;
1912 t = elemtype(t);
1913 }
1914 return result;
1915 }
1917 /**
1918 * Returns an ArrayType with the component type t
1919 *
1920 * @param t The component type of the ArrayType
1921 * @return the ArrayType for the given component
1922 */
1923 public ArrayType makeArrayType(Type t) {
1924 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) {
1925 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
1926 }
1927 return new ArrayType(t, syms.arrayClass);
1928 }
1929 // </editor-fold>
1931 // <editor-fold defaultstate="collapsed" desc="asSuper">
1932 /**
1933 * Return the (most specific) base type of t that starts with the
1934 * given symbol. If none exists, return null.
1935 *
1936 * @param t a type
1937 * @param sym a symbol
1938 */
1939 public Type asSuper(Type t, Symbol sym) {
1940 return asSuper.visit(t, sym);
1941 }
1942 // where
1943 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1945 public Type visitType(Type t, Symbol sym) {
1946 return null;
1947 }
1949 @Override
1950 public Type visitClassType(ClassType t, Symbol sym) {
1951 if (t.tsym == sym)
1952 return t;
1954 Type st = supertype(t);
1955 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR) || st.hasTag(ERROR)) {
1956 Type x = asSuper(st, sym);
1957 if (x != null)
1958 return x;
1959 }
1960 if ((sym.flags() & INTERFACE) != 0) {
1961 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1962 Type x = asSuper(l.head, sym);
1963 if (x != null)
1964 return x;
1965 }
1966 }
1967 return null;
1968 }
1970 @Override
1971 public Type visitArrayType(ArrayType t, Symbol sym) {
1972 return isSubtype(t, sym.type) ? sym.type : null;
1973 }
1975 @Override
1976 public Type visitTypeVar(TypeVar t, Symbol sym) {
1977 if (t.tsym == sym)
1978 return t;
1979 else
1980 return asSuper(t.bound, sym);
1981 }
1983 @Override
1984 public Type visitErrorType(ErrorType t, Symbol sym) {
1985 return t;
1986 }
1987 };
1989 /**
1990 * Return the base type of t or any of its outer types that starts
1991 * with the given symbol. If none exists, return null.
1992 *
1993 * @param t a type
1994 * @param sym a symbol
1995 */
1996 public Type asOuterSuper(Type t, Symbol sym) {
1997 switch (t.getTag()) {
1998 case CLASS:
1999 do {
2000 Type s = asSuper(t, sym);
2001 if (s != null) return s;
2002 t = t.getEnclosingType();
2003 } while (t.hasTag(CLASS));
2004 return null;
2005 case ARRAY:
2006 return isSubtype(t, sym.type) ? sym.type : null;
2007 case TYPEVAR:
2008 return asSuper(t, sym);
2009 case ERROR:
2010 return t;
2011 default:
2012 return null;
2013 }
2014 }
2016 /**
2017 * Return the base type of t or any of its enclosing types that
2018 * starts with the given symbol. If none exists, return null.
2019 *
2020 * @param t a type
2021 * @param sym a symbol
2022 */
2023 public Type asEnclosingSuper(Type t, Symbol sym) {
2024 switch (t.getTag()) {
2025 case CLASS:
2026 do {
2027 Type s = asSuper(t, sym);
2028 if (s != null) return s;
2029 Type outer = t.getEnclosingType();
2030 t = (outer.hasTag(CLASS)) ? outer :
2031 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
2032 Type.noType;
2033 } while (t.hasTag(CLASS));
2034 return null;
2035 case ARRAY:
2036 return isSubtype(t, sym.type) ? sym.type : null;
2037 case TYPEVAR:
2038 return asSuper(t, sym);
2039 case ERROR:
2040 return t;
2041 default:
2042 return null;
2043 }
2044 }
2045 // </editor-fold>
2047 // <editor-fold defaultstate="collapsed" desc="memberType">
2048 /**
2049 * The type of given symbol, seen as a member of t.
2050 *
2051 * @param t a type
2052 * @param sym a symbol
2053 */
2054 public Type memberType(Type t, Symbol sym) {
2055 return (sym.flags() & STATIC) != 0
2056 ? sym.type
2057 : memberType.visit(t, sym);
2058 }
2059 // where
2060 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
2062 public Type visitType(Type t, Symbol sym) {
2063 return sym.type;
2064 }
2066 @Override
2067 public Type visitWildcardType(WildcardType t, Symbol sym) {
2068 return memberType(upperBound(t), sym);
2069 }
2071 @Override
2072 public Type visitClassType(ClassType t, Symbol sym) {
2073 Symbol owner = sym.owner;
2074 long flags = sym.flags();
2075 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
2076 Type base = asOuterSuper(t, owner);
2077 //if t is an intersection type T = CT & I1 & I2 ... & In
2078 //its supertypes CT, I1, ... In might contain wildcards
2079 //so we need to go through capture conversion
2080 base = t.isCompound() ? capture(base) : base;
2081 if (base != null) {
2082 List<Type> ownerParams = owner.type.allparams();
2083 List<Type> baseParams = base.allparams();
2084 if (ownerParams.nonEmpty()) {
2085 if (baseParams.isEmpty()) {
2086 // then base is a raw type
2087 return erasure(sym.type);
2088 } else {
2089 return subst(sym.type, ownerParams, baseParams);
2090 }
2091 }
2092 }
2093 }
2094 return sym.type;
2095 }
2097 @Override
2098 public Type visitTypeVar(TypeVar t, Symbol sym) {
2099 return memberType(t.bound, sym);
2100 }
2102 @Override
2103 public Type visitErrorType(ErrorType t, Symbol sym) {
2104 return t;
2105 }
2106 };
2107 // </editor-fold>
2109 // <editor-fold defaultstate="collapsed" desc="isAssignable">
2110 public boolean isAssignable(Type t, Type s) {
2111 return isAssignable(t, s, noWarnings);
2112 }
2114 /**
2115 * Is t assignable to s?<br>
2116 * Equivalent to subtype except for constant values and raw
2117 * types.<br>
2118 * (not defined for Method and ForAll types)
2119 */
2120 public boolean isAssignable(Type t, Type s, Warner warn) {
2121 if (t.hasTag(ERROR))
2122 return true;
2123 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) {
2124 int value = ((Number)t.constValue()).intValue();
2125 switch (s.getTag()) {
2126 case BYTE:
2127 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
2128 return true;
2129 break;
2130 case CHAR:
2131 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
2132 return true;
2133 break;
2134 case SHORT:
2135 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
2136 return true;
2137 break;
2138 case INT:
2139 return true;
2140 case CLASS:
2141 switch (unboxedType(s).getTag()) {
2142 case BYTE:
2143 case CHAR:
2144 case SHORT:
2145 return isAssignable(t, unboxedType(s), warn);
2146 }
2147 break;
2148 }
2149 }
2150 return isConvertible(t, s, warn);
2151 }
2152 // </editor-fold>
2154 // <editor-fold defaultstate="collapsed" desc="erasure">
2155 /**
2156 * The erasure of t {@code |t|} -- the type that results when all
2157 * type parameters in t are deleted.
2158 */
2159 public Type erasure(Type t) {
2160 return eraseNotNeeded(t)? t : erasure(t, false);
2161 }
2162 //where
2163 private boolean eraseNotNeeded(Type t) {
2164 // We don't want to erase primitive types and String type as that
2165 // operation is idempotent. Also, erasing these could result in loss
2166 // of information such as constant values attached to such types.
2167 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2168 }
2170 private Type erasure(Type t, boolean recurse) {
2171 if (t.isPrimitive())
2172 return t; /* fast special case */
2173 else
2174 return erasure.visit(t, recurse);
2175 }
2176 // where
2177 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
2178 public Type visitType(Type t, Boolean recurse) {
2179 if (t.isPrimitive())
2180 return t; /*fast special case*/
2181 else
2182 return t.map(recurse ? erasureRecFun : erasureFun);
2183 }
2185 @Override
2186 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2187 return erasure(upperBound(t), recurse);
2188 }
2190 @Override
2191 public Type visitClassType(ClassType t, Boolean recurse) {
2192 Type erased = t.tsym.erasure(Types.this);
2193 if (recurse) {
2194 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
2195 }
2196 return erased;
2197 }
2199 @Override
2200 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2201 return erasure(t.bound, recurse);
2202 }
2204 @Override
2205 public Type visitErrorType(ErrorType t, Boolean recurse) {
2206 return t;
2207 }
2209 @Override
2210 public Type visitAnnotatedType(AnnotatedType t, Boolean recurse) {
2211 Type erased = erasure(t.underlyingType, recurse);
2212 if (erased.isAnnotated()) {
2213 // This can only happen when the underlying type is a
2214 // type variable and the upper bound of it is annotated.
2215 // The annotation on the type variable overrides the one
2216 // on the bound.
2217 erased = ((AnnotatedType)erased).underlyingType;
2218 }
2219 return new AnnotatedType(t.typeAnnotations, erased);
2220 }
2221 };
2223 private Mapping erasureFun = new Mapping ("erasure") {
2224 public Type apply(Type t) { return erasure(t); }
2225 };
2227 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
2228 public Type apply(Type t) { return erasureRecursive(t); }
2229 };
2231 public List<Type> erasure(List<Type> ts) {
2232 return Type.map(ts, erasureFun);
2233 }
2235 public Type erasureRecursive(Type t) {
2236 return erasure(t, true);
2237 }
2239 public List<Type> erasureRecursive(List<Type> ts) {
2240 return Type.map(ts, erasureRecFun);
2241 }
2242 // </editor-fold>
2244 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
2245 /**
2246 * Make a compound type from non-empty list of types
2247 *
2248 * @param bounds the types from which the compound type is formed
2249 * @param supertype is objectType if all bounds are interfaces,
2250 * null otherwise.
2251 */
2252 public Type makeCompoundType(List<Type> bounds) {
2253 return makeCompoundType(bounds, bounds.head.tsym.isInterface());
2254 }
2255 public Type makeCompoundType(List<Type> bounds, boolean allInterfaces) {
2256 Assert.check(bounds.nonEmpty());
2257 Type firstExplicitBound = bounds.head;
2258 if (allInterfaces) {
2259 bounds = bounds.prepend(syms.objectType);
2260 }
2261 ClassSymbol bc =
2262 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2263 Type.moreInfo
2264 ? names.fromString(bounds.toString())
2265 : names.empty,
2266 null,
2267 syms.noSymbol);
2268 bc.type = new IntersectionClassType(bounds, bc, allInterfaces);
2269 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
2270 syms.objectType : // error condition, recover
2271 erasure(firstExplicitBound);
2272 bc.members_field = new Scope(bc);
2273 return bc.type;
2274 }
2276 /**
2277 * A convenience wrapper for {@link #makeCompoundType(List)}; the
2278 * arguments are converted to a list and passed to the other
2279 * method. Note that this might cause a symbol completion.
2280 * Hence, this version of makeCompoundType may not be called
2281 * during a classfile read.
2282 */
2283 public Type makeCompoundType(Type bound1, Type bound2) {
2284 return makeCompoundType(List.of(bound1, bound2));
2285 }
2286 // </editor-fold>
2288 // <editor-fold defaultstate="collapsed" desc="supertype">
2289 public Type supertype(Type t) {
2290 return supertype.visit(t);
2291 }
2292 // where
2293 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2295 public Type visitType(Type t, Void ignored) {
2296 // A note on wildcards: there is no good way to
2297 // determine a supertype for a super bounded wildcard.
2298 return null;
2299 }
2301 @Override
2302 public Type visitClassType(ClassType t, Void ignored) {
2303 if (t.supertype_field == null) {
2304 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2305 // An interface has no superclass; its supertype is Object.
2306 if (t.isInterface())
2307 supertype = ((ClassType)t.tsym.type).supertype_field;
2308 if (t.supertype_field == null) {
2309 List<Type> actuals = classBound(t).allparams();
2310 List<Type> formals = t.tsym.type.allparams();
2311 if (t.hasErasedSupertypes()) {
2312 t.supertype_field = erasureRecursive(supertype);
2313 } else if (formals.nonEmpty()) {
2314 t.supertype_field = subst(supertype, formals, actuals);
2315 }
2316 else {
2317 t.supertype_field = supertype;
2318 }
2319 }
2320 }
2321 return t.supertype_field;
2322 }
2324 /**
2325 * The supertype is always a class type. If the type
2326 * variable's bounds start with a class type, this is also
2327 * the supertype. Otherwise, the supertype is
2328 * java.lang.Object.
2329 */
2330 @Override
2331 public Type visitTypeVar(TypeVar t, Void ignored) {
2332 if (t.bound.hasTag(TYPEVAR) ||
2333 (!t.bound.isCompound() && !t.bound.isInterface())) {
2334 return t.bound;
2335 } else {
2336 return supertype(t.bound);
2337 }
2338 }
2340 @Override
2341 public Type visitArrayType(ArrayType t, Void ignored) {
2342 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2343 return arraySuperType();
2344 else
2345 return new ArrayType(supertype(t.elemtype), t.tsym);
2346 }
2348 @Override
2349 public Type visitErrorType(ErrorType t, Void ignored) {
2350 return Type.noType;
2351 }
2352 };
2353 // </editor-fold>
2355 // <editor-fold defaultstate="collapsed" desc="interfaces">
2356 /**
2357 * Return the interfaces implemented by this class.
2358 */
2359 public List<Type> interfaces(Type t) {
2360 return interfaces.visit(t);
2361 }
2362 // where
2363 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2365 public List<Type> visitType(Type t, Void ignored) {
2366 return List.nil();
2367 }
2369 @Override
2370 public List<Type> visitClassType(ClassType t, Void ignored) {
2371 if (t.interfaces_field == null) {
2372 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2373 if (t.interfaces_field == null) {
2374 // If t.interfaces_field is null, then t must
2375 // be a parameterized type (not to be confused
2376 // with a generic type declaration).
2377 // Terminology:
2378 // Parameterized type: List<String>
2379 // Generic type declaration: class List<E> { ... }
2380 // So t corresponds to List<String> and
2381 // t.tsym.type corresponds to List<E>.
2382 // The reason t must be parameterized type is
2383 // that completion will happen as a side
2384 // effect of calling
2385 // ClassSymbol.getInterfaces. Since
2386 // t.interfaces_field is null after
2387 // completion, we can assume that t is not the
2388 // type of a class/interface declaration.
2389 Assert.check(t != t.tsym.type, t);
2390 List<Type> actuals = t.allparams();
2391 List<Type> formals = t.tsym.type.allparams();
2392 if (t.hasErasedSupertypes()) {
2393 t.interfaces_field = erasureRecursive(interfaces);
2394 } else if (formals.nonEmpty()) {
2395 t.interfaces_field =
2396 upperBounds(subst(interfaces, formals, actuals));
2397 }
2398 else {
2399 t.interfaces_field = interfaces;
2400 }
2401 }
2402 }
2403 return t.interfaces_field;
2404 }
2406 @Override
2407 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2408 if (t.bound.isCompound())
2409 return interfaces(t.bound);
2411 if (t.bound.isInterface())
2412 return List.of(t.bound);
2414 return List.nil();
2415 }
2416 };
2418 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2419 for (Type i2 : interfaces(origin.type)) {
2420 if (isym == i2.tsym) return true;
2421 }
2422 return false;
2423 }
2424 // </editor-fold>
2426 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2427 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
2429 public boolean isDerivedRaw(Type t) {
2430 Boolean result = isDerivedRawCache.get(t);
2431 if (result == null) {
2432 result = isDerivedRawInternal(t);
2433 isDerivedRawCache.put(t, result);
2434 }
2435 return result;
2436 }
2438 public boolean isDerivedRawInternal(Type t) {
2439 if (t.isErroneous())
2440 return false;
2441 return
2442 t.isRaw() ||
2443 supertype(t) != null && isDerivedRaw(supertype(t)) ||
2444 isDerivedRaw(interfaces(t));
2445 }
2447 public boolean isDerivedRaw(List<Type> ts) {
2448 List<Type> l = ts;
2449 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2450 return l.nonEmpty();
2451 }
2452 // </editor-fold>
2454 // <editor-fold defaultstate="collapsed" desc="setBounds">
2455 /**
2456 * Set the bounds field of the given type variable to reflect a
2457 * (possibly multiple) list of bounds.
2458 * @param t a type variable
2459 * @param bounds the bounds, must be nonempty
2460 * @param supertype is objectType if all bounds are interfaces,
2461 * null otherwise.
2462 */
2463 public void setBounds(TypeVar t, List<Type> bounds) {
2464 setBounds(t, bounds, bounds.head.tsym.isInterface());
2465 }
2467 /**
2468 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
2469 * third parameter is computed directly, as follows: if all
2470 * all bounds are interface types, the computed supertype is Object,
2471 * otherwise the supertype is simply left null (in this case, the supertype
2472 * is assumed to be the head of the bound list passed as second argument).
2473 * Note that this check might cause a symbol completion. Hence, this version of
2474 * setBounds may not be called during a classfile read.
2475 */
2476 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2477 t.bound = bounds.tail.isEmpty() ?
2478 bounds.head :
2479 makeCompoundType(bounds, allInterfaces);
2480 t.rank_field = -1;
2481 }
2482 // </editor-fold>
2484 // <editor-fold defaultstate="collapsed" desc="getBounds">
2485 /**
2486 * Return list of bounds of the given type variable.
2487 */
2488 public List<Type> getBounds(TypeVar t) {
2489 if (t.bound.hasTag(NONE))
2490 return List.nil();
2491 else if (t.bound.isErroneous() || !t.bound.isCompound())
2492 return List.of(t.bound);
2493 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2494 return interfaces(t).prepend(supertype(t));
2495 else
2496 // No superclass was given in bounds.
2497 // In this case, supertype is Object, erasure is first interface.
2498 return interfaces(t);
2499 }
2500 // </editor-fold>
2502 // <editor-fold defaultstate="collapsed" desc="classBound">
2503 /**
2504 * If the given type is a (possibly selected) type variable,
2505 * return the bounding class of this type, otherwise return the
2506 * type itself.
2507 */
2508 public Type classBound(Type t) {
2509 return classBound.visit(t);
2510 }
2511 // where
2512 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2514 public Type visitType(Type t, Void ignored) {
2515 return t;
2516 }
2518 @Override
2519 public Type visitClassType(ClassType t, Void ignored) {
2520 Type outer1 = classBound(t.getEnclosingType());
2521 if (outer1 != t.getEnclosingType())
2522 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
2523 else
2524 return t;
2525 }
2527 @Override
2528 public Type visitTypeVar(TypeVar t, Void ignored) {
2529 return classBound(supertype(t));
2530 }
2532 @Override
2533 public Type visitErrorType(ErrorType t, Void ignored) {
2534 return t;
2535 }
2536 };
2537 // </editor-fold>
2539 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
2540 /**
2541 * Returns true iff the first signature is a <em>sub
2542 * signature</em> of the other. This is <b>not</b> an equivalence
2543 * relation.
2544 *
2545 * @jls section 8.4.2.
2546 * @see #overrideEquivalent(Type t, Type s)
2547 * @param t first signature (possibly raw).
2548 * @param s second signature (could be subjected to erasure).
2549 * @return true if t is a sub signature of s.
2550 */
2551 public boolean isSubSignature(Type t, Type s) {
2552 return isSubSignature(t, s, true);
2553 }
2555 public boolean isSubSignature(Type t, Type s, boolean strict) {
2556 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2557 }
2559 /**
2560 * Returns true iff these signatures are related by <em>override
2561 * equivalence</em>. This is the natural extension of
2562 * isSubSignature to an equivalence relation.
2563 *
2564 * @jls section 8.4.2.
2565 * @see #isSubSignature(Type t, Type s)
2566 * @param t a signature (possible raw, could be subjected to
2567 * erasure).
2568 * @param s a signature (possible raw, could be subjected to
2569 * erasure).
2570 * @return true if either argument is a sub signature of the other.
2571 */
2572 public boolean overrideEquivalent(Type t, Type s) {
2573 return hasSameArgs(t, s) ||
2574 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2575 }
2577 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2578 for (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) {
2579 if (msym.overrides(e.sym, origin, Types.this, true)) {
2580 return true;
2581 }
2582 }
2583 return false;
2584 }
2586 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2587 class ImplementationCache {
2589 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2590 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2592 class Entry {
2593 final MethodSymbol cachedImpl;
2594 final Filter<Symbol> implFilter;
2595 final boolean checkResult;
2596 final int prevMark;
2598 public Entry(MethodSymbol cachedImpl,
2599 Filter<Symbol> scopeFilter,
2600 boolean checkResult,
2601 int prevMark) {
2602 this.cachedImpl = cachedImpl;
2603 this.implFilter = scopeFilter;
2604 this.checkResult = checkResult;
2605 this.prevMark = prevMark;
2606 }
2608 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2609 return this.implFilter == scopeFilter &&
2610 this.checkResult == checkResult &&
2611 this.prevMark == mark;
2612 }
2613 }
2615 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2616 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2617 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2618 if (cache == null) {
2619 cache = new HashMap<TypeSymbol, Entry>();
2620 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2621 }
2622 Entry e = cache.get(origin);
2623 CompoundScope members = membersClosure(origin.type, true);
2624 if (e == null ||
2625 !e.matches(implFilter, checkResult, members.getMark())) {
2626 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2627 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2628 return impl;
2629 }
2630 else {
2631 return e.cachedImpl;
2632 }
2633 }
2635 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2636 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
2637 while (t.hasTag(TYPEVAR))
2638 t = t.getUpperBound();
2639 TypeSymbol c = t.tsym;
2640 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2641 e.scope != null;
2642 e = e.next(implFilter)) {
2643 if (e.sym != null &&
2644 e.sym.overrides(ms, origin, Types.this, checkResult))
2645 return (MethodSymbol)e.sym;
2646 }
2647 }
2648 return null;
2649 }
2650 }
2652 private ImplementationCache implCache = new ImplementationCache();
2654 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2655 return implCache.get(ms, origin, checkResult, implFilter);
2656 }
2657 // </editor-fold>
2659 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2660 class MembersClosureCache extends SimpleVisitor<CompoundScope, Boolean> {
2662 private WeakHashMap<TypeSymbol, Entry> _map =
2663 new WeakHashMap<TypeSymbol, Entry>();
2665 class Entry {
2666 final boolean skipInterfaces;
2667 final CompoundScope compoundScope;
2669 public Entry(boolean skipInterfaces, CompoundScope compoundScope) {
2670 this.skipInterfaces = skipInterfaces;
2671 this.compoundScope = compoundScope;
2672 }
2674 boolean matches(boolean skipInterfaces) {
2675 return this.skipInterfaces == skipInterfaces;
2676 }
2677 }
2679 List<TypeSymbol> seenTypes = List.nil();
2681 /** members closure visitor methods **/
2683 public CompoundScope visitType(Type t, Boolean skipInterface) {
2684 return null;
2685 }
2687 @Override
2688 public CompoundScope visitClassType(ClassType t, Boolean skipInterface) {
2689 if (seenTypes.contains(t.tsym)) {
2690 //this is possible when an interface is implemented in multiple
2691 //superclasses, or when a classs hierarchy is circular - in such
2692 //cases we don't need to recurse (empty scope is returned)
2693 return new CompoundScope(t.tsym);
2694 }
2695 try {
2696 seenTypes = seenTypes.prepend(t.tsym);
2697 ClassSymbol csym = (ClassSymbol)t.tsym;
2698 Entry e = _map.get(csym);
2699 if (e == null || !e.matches(skipInterface)) {
2700 CompoundScope membersClosure = new CompoundScope(csym);
2701 if (!skipInterface) {
2702 for (Type i : interfaces(t)) {
2703 membersClosure.addSubScope(visit(i, skipInterface));
2704 }
2705 }
2706 membersClosure.addSubScope(visit(supertype(t), skipInterface));
2707 membersClosure.addSubScope(csym.members());
2708 e = new Entry(skipInterface, membersClosure);
2709 _map.put(csym, e);
2710 }
2711 return e.compoundScope;
2712 }
2713 finally {
2714 seenTypes = seenTypes.tail;
2715 }
2716 }
2718 @Override
2719 public CompoundScope visitTypeVar(TypeVar t, Boolean skipInterface) {
2720 return visit(t.getUpperBound(), skipInterface);
2721 }
2722 }
2724 private MembersClosureCache membersCache = new MembersClosureCache();
2726 public CompoundScope membersClosure(Type site, boolean skipInterface) {
2727 return membersCache.visit(site, skipInterface);
2728 }
2729 // </editor-fold>
2732 //where
2733 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
2734 Filter<Symbol> filter = new MethodFilter(ms, site);
2735 List<MethodSymbol> candidates = List.nil();
2736 for (Symbol s : membersClosure(site, false).getElements(filter)) {
2737 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
2738 return List.of((MethodSymbol)s);
2739 } else if (!candidates.contains(s)) {
2740 candidates = candidates.prepend((MethodSymbol)s);
2741 }
2742 }
2743 return prune(candidates);
2744 }
2746 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
2747 ListBuffer<MethodSymbol> methodsMin = ListBuffer.lb();
2748 for (MethodSymbol m1 : methods) {
2749 boolean isMin_m1 = true;
2750 for (MethodSymbol m2 : methods) {
2751 if (m1 == m2) continue;
2752 if (m2.owner != m1.owner &&
2753 asSuper(m2.owner.type, m1.owner) != null) {
2754 isMin_m1 = false;
2755 break;
2756 }
2757 }
2758 if (isMin_m1)
2759 methodsMin.append(m1);
2760 }
2761 return methodsMin.toList();
2762 }
2763 // where
2764 private class MethodFilter implements Filter<Symbol> {
2766 Symbol msym;
2767 Type site;
2769 MethodFilter(Symbol msym, Type site) {
2770 this.msym = msym;
2771 this.site = site;
2772 }
2774 public boolean accepts(Symbol s) {
2775 return s.kind == Kinds.MTH &&
2776 s.name == msym.name &&
2777 (s.flags() & SYNTHETIC) == 0 &&
2778 s.isInheritedIn(site.tsym, Types.this) &&
2779 overrideEquivalent(memberType(site, s), memberType(site, msym));
2780 }
2781 };
2782 // </editor-fold>
2784 /**
2785 * Does t have the same arguments as s? It is assumed that both
2786 * types are (possibly polymorphic) method types. Monomorphic
2787 * method types "have the same arguments", if their argument lists
2788 * are equal. Polymorphic method types "have the same arguments",
2789 * if they have the same arguments after renaming all type
2790 * variables of one to corresponding type variables in the other,
2791 * where correspondence is by position in the type parameter list.
2792 */
2793 public boolean hasSameArgs(Type t, Type s) {
2794 return hasSameArgs(t, s, true);
2795 }
2797 public boolean hasSameArgs(Type t, Type s, boolean strict) {
2798 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
2799 }
2801 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
2802 return hasSameArgs.visit(t, s);
2803 }
2804 // where
2805 private class HasSameArgs extends TypeRelation {
2807 boolean strict;
2809 public HasSameArgs(boolean strict) {
2810 this.strict = strict;
2811 }
2813 public Boolean visitType(Type t, Type s) {
2814 throw new AssertionError();
2815 }
2817 @Override
2818 public Boolean visitMethodType(MethodType t, Type s) {
2819 return s.hasTag(METHOD)
2820 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2821 }
2823 @Override
2824 public Boolean visitForAll(ForAll t, Type s) {
2825 if (!s.hasTag(FORALL))
2826 return strict ? false : visitMethodType(t.asMethodType(), s);
2828 ForAll forAll = (ForAll)s;
2829 return hasSameBounds(t, forAll)
2830 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2831 }
2833 @Override
2834 public Boolean visitErrorType(ErrorType t, Type s) {
2835 return false;
2836 }
2837 };
2839 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
2840 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
2842 // </editor-fold>
2844 // <editor-fold defaultstate="collapsed" desc="subst">
2845 public List<Type> subst(List<Type> ts,
2846 List<Type> from,
2847 List<Type> to) {
2848 return new Subst(from, to).subst(ts);
2849 }
2851 /**
2852 * Substitute all occurrences of a type in `from' with the
2853 * corresponding type in `to' in 't'. Match lists `from' and `to'
2854 * from the right: If lists have different length, discard leading
2855 * elements of the longer list.
2856 */
2857 public Type subst(Type t, List<Type> from, List<Type> to) {
2858 return new Subst(from, to).subst(t);
2859 }
2861 private class Subst extends UnaryVisitor<Type> {
2862 List<Type> from;
2863 List<Type> to;
2865 public Subst(List<Type> from, List<Type> to) {
2866 int fromLength = from.length();
2867 int toLength = to.length();
2868 while (fromLength > toLength) {
2869 fromLength--;
2870 from = from.tail;
2871 }
2872 while (fromLength < toLength) {
2873 toLength--;
2874 to = to.tail;
2875 }
2876 this.from = from;
2877 this.to = to;
2878 }
2880 Type subst(Type t) {
2881 if (from.tail == null)
2882 return t;
2883 else
2884 return visit(t);
2885 }
2887 List<Type> subst(List<Type> ts) {
2888 if (from.tail == null)
2889 return ts;
2890 boolean wild = false;
2891 if (ts.nonEmpty() && from.nonEmpty()) {
2892 Type head1 = subst(ts.head);
2893 List<Type> tail1 = subst(ts.tail);
2894 if (head1 != ts.head || tail1 != ts.tail)
2895 return tail1.prepend(head1);
2896 }
2897 return ts;
2898 }
2900 public Type visitType(Type t, Void ignored) {
2901 return t;
2902 }
2904 @Override
2905 public Type visitMethodType(MethodType t, Void ignored) {
2906 List<Type> argtypes = subst(t.argtypes);
2907 Type restype = subst(t.restype);
2908 List<Type> thrown = subst(t.thrown);
2909 if (argtypes == t.argtypes &&
2910 restype == t.restype &&
2911 thrown == t.thrown)
2912 return t;
2913 else
2914 return new MethodType(argtypes, restype, thrown, t.tsym);
2915 }
2917 @Override
2918 public Type visitTypeVar(TypeVar t, Void ignored) {
2919 for (List<Type> from = this.from, to = this.to;
2920 from.nonEmpty();
2921 from = from.tail, to = to.tail) {
2922 if (t == from.head) {
2923 return to.head.withTypeVar(t);
2924 }
2925 }
2926 return t;
2927 }
2929 @Override
2930 public Type visitClassType(ClassType t, Void ignored) {
2931 if (!t.isCompound()) {
2932 List<Type> typarams = t.getTypeArguments();
2933 List<Type> typarams1 = subst(typarams);
2934 Type outer = t.getEnclosingType();
2935 Type outer1 = subst(outer);
2936 if (typarams1 == typarams && outer1 == outer)
2937 return t;
2938 else
2939 return new ClassType(outer1, typarams1, t.tsym);
2940 } else {
2941 Type st = subst(supertype(t));
2942 List<Type> is = upperBounds(subst(interfaces(t)));
2943 if (st == supertype(t) && is == interfaces(t))
2944 return t;
2945 else
2946 return makeCompoundType(is.prepend(st));
2947 }
2948 }
2950 @Override
2951 public Type visitWildcardType(WildcardType t, Void ignored) {
2952 Type bound = t.type;
2953 if (t.kind != BoundKind.UNBOUND)
2954 bound = subst(bound);
2955 if (bound == t.type) {
2956 return t;
2957 } else {
2958 if (t.isExtendsBound() && bound.isExtendsBound())
2959 bound = upperBound(bound);
2960 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2961 }
2962 }
2964 @Override
2965 public Type visitArrayType(ArrayType t, Void ignored) {
2966 Type elemtype = subst(t.elemtype);
2967 if (elemtype == t.elemtype)
2968 return t;
2969 else
2970 return new ArrayType(elemtype, t.tsym);
2971 }
2973 @Override
2974 public Type visitForAll(ForAll t, Void ignored) {
2975 if (Type.containsAny(to, t.tvars)) {
2976 //perform alpha-renaming of free-variables in 't'
2977 //if 'to' types contain variables that are free in 't'
2978 List<Type> freevars = newInstances(t.tvars);
2979 t = new ForAll(freevars,
2980 Types.this.subst(t.qtype, t.tvars, freevars));
2981 }
2982 List<Type> tvars1 = substBounds(t.tvars, from, to);
2983 Type qtype1 = subst(t.qtype);
2984 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2985 return t;
2986 } else if (tvars1 == t.tvars) {
2987 return new ForAll(tvars1, qtype1);
2988 } else {
2989 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2990 }
2991 }
2993 @Override
2994 public Type visitErrorType(ErrorType t, Void ignored) {
2995 return t;
2996 }
2997 }
2999 public List<Type> substBounds(List<Type> tvars,
3000 List<Type> from,
3001 List<Type> to) {
3002 if (tvars.isEmpty())
3003 return tvars;
3004 ListBuffer<Type> newBoundsBuf = lb();
3005 boolean changed = false;
3006 // calculate new bounds
3007 for (Type t : tvars) {
3008 TypeVar tv = (TypeVar) t;
3009 Type bound = subst(tv.bound, from, to);
3010 if (bound != tv.bound)
3011 changed = true;
3012 newBoundsBuf.append(bound);
3013 }
3014 if (!changed)
3015 return tvars;
3016 ListBuffer<Type> newTvars = lb();
3017 // create new type variables without bounds
3018 for (Type t : tvars) {
3019 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
3020 }
3021 // the new bounds should use the new type variables in place
3022 // of the old
3023 List<Type> newBounds = newBoundsBuf.toList();
3024 from = tvars;
3025 to = newTvars.toList();
3026 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
3027 newBounds.head = subst(newBounds.head, from, to);
3028 }
3029 newBounds = newBoundsBuf.toList();
3030 // set the bounds of new type variables to the new bounds
3031 for (Type t : newTvars.toList()) {
3032 TypeVar tv = (TypeVar) t;
3033 tv.bound = newBounds.head;
3034 newBounds = newBounds.tail;
3035 }
3036 return newTvars.toList();
3037 }
3039 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
3040 Type bound1 = subst(t.bound, from, to);
3041 if (bound1 == t.bound)
3042 return t;
3043 else {
3044 // create new type variable without bounds
3045 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
3046 // the new bound should use the new type variable in place
3047 // of the old
3048 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
3049 return tv;
3050 }
3051 }
3052 // </editor-fold>
3054 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
3055 /**
3056 * Does t have the same bounds for quantified variables as s?
3057 */
3058 boolean hasSameBounds(ForAll t, ForAll s) {
3059 List<Type> l1 = t.tvars;
3060 List<Type> l2 = s.tvars;
3061 while (l1.nonEmpty() && l2.nonEmpty() &&
3062 isSameType(l1.head.getUpperBound(),
3063 subst(l2.head.getUpperBound(),
3064 s.tvars,
3065 t.tvars))) {
3066 l1 = l1.tail;
3067 l2 = l2.tail;
3068 }
3069 return l1.isEmpty() && l2.isEmpty();
3070 }
3071 // </editor-fold>
3073 // <editor-fold defaultstate="collapsed" desc="newInstances">
3074 /** Create new vector of type variables from list of variables
3075 * changing all recursive bounds from old to new list.
3076 */
3077 public List<Type> newInstances(List<Type> tvars) {
3078 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
3079 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
3080 TypeVar tv = (TypeVar) l.head;
3081 tv.bound = subst(tv.bound, tvars, tvars1);
3082 }
3083 return tvars1;
3084 }
3085 private static final Mapping newInstanceFun = new Mapping("newInstanceFun") {
3086 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
3087 };
3088 // </editor-fold>
3090 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
3091 return original.accept(methodWithParameters, newParams);
3092 }
3093 // where
3094 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
3095 public Type visitType(Type t, List<Type> newParams) {
3096 throw new IllegalArgumentException("Not a method type: " + t);
3097 }
3098 public Type visitMethodType(MethodType t, List<Type> newParams) {
3099 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
3100 }
3101 public Type visitForAll(ForAll t, List<Type> newParams) {
3102 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
3103 }
3104 };
3106 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
3107 return original.accept(methodWithThrown, newThrown);
3108 }
3109 // where
3110 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
3111 public Type visitType(Type t, List<Type> newThrown) {
3112 throw new IllegalArgumentException("Not a method type: " + t);
3113 }
3114 public Type visitMethodType(MethodType t, List<Type> newThrown) {
3115 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
3116 }
3117 public Type visitForAll(ForAll t, List<Type> newThrown) {
3118 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
3119 }
3120 };
3122 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
3123 return original.accept(methodWithReturn, newReturn);
3124 }
3125 // where
3126 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
3127 public Type visitType(Type t, Type newReturn) {
3128 throw new IllegalArgumentException("Not a method type: " + t);
3129 }
3130 public Type visitMethodType(MethodType t, Type newReturn) {
3131 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym);
3132 }
3133 public Type visitForAll(ForAll t, Type newReturn) {
3134 return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
3135 }
3136 };
3138 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3139 public Type createErrorType(Type originalType) {
3140 return new ErrorType(originalType, syms.errSymbol);
3141 }
3143 public Type createErrorType(ClassSymbol c, Type originalType) {
3144 return new ErrorType(c, originalType);
3145 }
3147 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3148 return new ErrorType(name, container, originalType);
3149 }
3150 // </editor-fold>
3152 // <editor-fold defaultstate="collapsed" desc="rank">
3153 /**
3154 * The rank of a class is the length of the longest path between
3155 * the class and java.lang.Object in the class inheritance
3156 * graph. Undefined for all but reference types.
3157 */
3158 public int rank(Type t) {
3159 t = t.unannotatedType();
3160 switch(t.getTag()) {
3161 case CLASS: {
3162 ClassType cls = (ClassType)t;
3163 if (cls.rank_field < 0) {
3164 Name fullname = cls.tsym.getQualifiedName();
3165 if (fullname == names.java_lang_Object)
3166 cls.rank_field = 0;
3167 else {
3168 int r = rank(supertype(cls));
3169 for (List<Type> l = interfaces(cls);
3170 l.nonEmpty();
3171 l = l.tail) {
3172 if (rank(l.head) > r)
3173 r = rank(l.head);
3174 }
3175 cls.rank_field = r + 1;
3176 }
3177 }
3178 return cls.rank_field;
3179 }
3180 case TYPEVAR: {
3181 TypeVar tvar = (TypeVar)t;
3182 if (tvar.rank_field < 0) {
3183 int r = rank(supertype(tvar));
3184 for (List<Type> l = interfaces(tvar);
3185 l.nonEmpty();
3186 l = l.tail) {
3187 if (rank(l.head) > r) r = rank(l.head);
3188 }
3189 tvar.rank_field = r + 1;
3190 }
3191 return tvar.rank_field;
3192 }
3193 case ERROR:
3194 return 0;
3195 default:
3196 throw new AssertionError();
3197 }
3198 }
3199 // </editor-fold>
3201 /**
3202 * Helper method for generating a string representation of a given type
3203 * accordingly to a given locale
3204 */
3205 public String toString(Type t, Locale locale) {
3206 return Printer.createStandardPrinter(messages).visit(t, locale);
3207 }
3209 /**
3210 * Helper method for generating a string representation of a given type
3211 * accordingly to a given locale
3212 */
3213 public String toString(Symbol t, Locale locale) {
3214 return Printer.createStandardPrinter(messages).visit(t, locale);
3215 }
3217 // <editor-fold defaultstate="collapsed" desc="toString">
3218 /**
3219 * This toString is slightly more descriptive than the one on Type.
3220 *
3221 * @deprecated Types.toString(Type t, Locale l) provides better support
3222 * for localization
3223 */
3224 @Deprecated
3225 public String toString(Type t) {
3226 if (t.hasTag(FORALL)) {
3227 ForAll forAll = (ForAll)t;
3228 return typaramsString(forAll.tvars) + forAll.qtype;
3229 }
3230 return "" + t;
3231 }
3232 // where
3233 private String typaramsString(List<Type> tvars) {
3234 StringBuilder s = new StringBuilder();
3235 s.append('<');
3236 boolean first = true;
3237 for (Type t : tvars) {
3238 if (!first) s.append(", ");
3239 first = false;
3240 appendTyparamString(((TypeVar)t.unannotatedType()), s);
3241 }
3242 s.append('>');
3243 return s.toString();
3244 }
3245 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3246 buf.append(t);
3247 if (t.bound == null ||
3248 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
3249 return;
3250 buf.append(" extends "); // Java syntax; no need for i18n
3251 Type bound = t.bound;
3252 if (!bound.isCompound()) {
3253 buf.append(bound);
3254 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3255 buf.append(supertype(t));
3256 for (Type intf : interfaces(t)) {
3257 buf.append('&');
3258 buf.append(intf);
3259 }
3260 } else {
3261 // No superclass was given in bounds.
3262 // In this case, supertype is Object, erasure is first interface.
3263 boolean first = true;
3264 for (Type intf : interfaces(t)) {
3265 if (!first) buf.append('&');
3266 first = false;
3267 buf.append(intf);
3268 }
3269 }
3270 }
3271 // </editor-fold>
3273 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3274 /**
3275 * A cache for closures.
3276 *
3277 * <p>A closure is a list of all the supertypes and interfaces of
3278 * a class or interface type, ordered by ClassSymbol.precedes
3279 * (that is, subclasses come first, arbitrary but fixed
3280 * otherwise).
3281 */
3282 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
3284 /**
3285 * Returns the closure of a class or interface type.
3286 */
3287 public List<Type> closure(Type t) {
3288 List<Type> cl = closureCache.get(t);
3289 if (cl == null) {
3290 Type st = supertype(t);
3291 if (!t.isCompound()) {
3292 if (st.hasTag(CLASS)) {
3293 cl = insert(closure(st), t);
3294 } else if (st.hasTag(TYPEVAR)) {
3295 cl = closure(st).prepend(t);
3296 } else {
3297 cl = List.of(t);
3298 }
3299 } else {
3300 cl = closure(supertype(t));
3301 }
3302 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3303 cl = union(cl, closure(l.head));
3304 closureCache.put(t, cl);
3305 }
3306 return cl;
3307 }
3309 /**
3310 * Insert a type in a closure
3311 */
3312 public List<Type> insert(List<Type> cl, Type t) {
3313 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
3314 return cl.prepend(t);
3315 } else if (cl.head.tsym.precedes(t.tsym, this)) {
3316 return insert(cl.tail, t).prepend(cl.head);
3317 } else {
3318 return cl;
3319 }
3320 }
3322 /**
3323 * Form the union of two closures
3324 */
3325 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3326 if (cl1.isEmpty()) {
3327 return cl2;
3328 } else if (cl2.isEmpty()) {
3329 return cl1;
3330 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
3331 return union(cl1.tail, cl2).prepend(cl1.head);
3332 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3333 return union(cl1, cl2.tail).prepend(cl2.head);
3334 } else {
3335 return union(cl1.tail, cl2.tail).prepend(cl1.head);
3336 }
3337 }
3339 /**
3340 * Intersect two closures
3341 */
3342 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3343 if (cl1 == cl2)
3344 return cl1;
3345 if (cl1.isEmpty() || cl2.isEmpty())
3346 return List.nil();
3347 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3348 return intersect(cl1.tail, cl2);
3349 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3350 return intersect(cl1, cl2.tail);
3351 if (isSameType(cl1.head, cl2.head))
3352 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3353 if (cl1.head.tsym == cl2.head.tsym &&
3354 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) {
3355 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3356 Type merge = merge(cl1.head,cl2.head);
3357 return intersect(cl1.tail, cl2.tail).prepend(merge);
3358 }
3359 if (cl1.head.isRaw() || cl2.head.isRaw())
3360 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3361 }
3362 return intersect(cl1.tail, cl2.tail);
3363 }
3364 // where
3365 class TypePair {
3366 final Type t1;
3367 final Type t2;
3368 TypePair(Type t1, Type t2) {
3369 this.t1 = t1;
3370 this.t2 = t2;
3371 }
3372 @Override
3373 public int hashCode() {
3374 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3375 }
3376 @Override
3377 public boolean equals(Object obj) {
3378 if (!(obj instanceof TypePair))
3379 return false;
3380 TypePair typePair = (TypePair)obj;
3381 return isSameType(t1, typePair.t1)
3382 && isSameType(t2, typePair.t2);
3383 }
3384 }
3385 Set<TypePair> mergeCache = new HashSet<TypePair>();
3386 private Type merge(Type c1, Type c2) {
3387 ClassType class1 = (ClassType) c1;
3388 List<Type> act1 = class1.getTypeArguments();
3389 ClassType class2 = (ClassType) c2;
3390 List<Type> act2 = class2.getTypeArguments();
3391 ListBuffer<Type> merged = new ListBuffer<Type>();
3392 List<Type> typarams = class1.tsym.type.getTypeArguments();
3394 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3395 if (containsType(act1.head, act2.head)) {
3396 merged.append(act1.head);
3397 } else if (containsType(act2.head, act1.head)) {
3398 merged.append(act2.head);
3399 } else {
3400 TypePair pair = new TypePair(c1, c2);
3401 Type m;
3402 if (mergeCache.add(pair)) {
3403 m = new WildcardType(lub(upperBound(act1.head),
3404 upperBound(act2.head)),
3405 BoundKind.EXTENDS,
3406 syms.boundClass);
3407 mergeCache.remove(pair);
3408 } else {
3409 m = new WildcardType(syms.objectType,
3410 BoundKind.UNBOUND,
3411 syms.boundClass);
3412 }
3413 merged.append(m.withTypeVar(typarams.head));
3414 }
3415 act1 = act1.tail;
3416 act2 = act2.tail;
3417 typarams = typarams.tail;
3418 }
3419 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3420 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
3421 }
3423 /**
3424 * Return the minimum type of a closure, a compound type if no
3425 * unique minimum exists.
3426 */
3427 private Type compoundMin(List<Type> cl) {
3428 if (cl.isEmpty()) return syms.objectType;
3429 List<Type> compound = closureMin(cl);
3430 if (compound.isEmpty())
3431 return null;
3432 else if (compound.tail.isEmpty())
3433 return compound.head;
3434 else
3435 return makeCompoundType(compound);
3436 }
3438 /**
3439 * Return the minimum types of a closure, suitable for computing
3440 * compoundMin or glb.
3441 */
3442 private List<Type> closureMin(List<Type> cl) {
3443 ListBuffer<Type> classes = lb();
3444 ListBuffer<Type> interfaces = lb();
3445 while (!cl.isEmpty()) {
3446 Type current = cl.head;
3447 if (current.isInterface())
3448 interfaces.append(current);
3449 else
3450 classes.append(current);
3451 ListBuffer<Type> candidates = lb();
3452 for (Type t : cl.tail) {
3453 if (!isSubtypeNoCapture(current, t))
3454 candidates.append(t);
3455 }
3456 cl = candidates.toList();
3457 }
3458 return classes.appendList(interfaces).toList();
3459 }
3461 /**
3462 * Return the least upper bound of pair of types. if the lub does
3463 * not exist return null.
3464 */
3465 public Type lub(Type t1, Type t2) {
3466 return lub(List.of(t1, t2));
3467 }
3469 /**
3470 * Return the least upper bound (lub) of set of types. If the lub
3471 * does not exist return the type of null (bottom).
3472 */
3473 public Type lub(List<Type> ts) {
3474 final int ARRAY_BOUND = 1;
3475 final int CLASS_BOUND = 2;
3476 int boundkind = 0;
3477 for (Type t : ts) {
3478 switch (t.getTag()) {
3479 case CLASS:
3480 boundkind |= CLASS_BOUND;
3481 break;
3482 case ARRAY:
3483 boundkind |= ARRAY_BOUND;
3484 break;
3485 case TYPEVAR:
3486 do {
3487 t = t.getUpperBound();
3488 } while (t.hasTag(TYPEVAR));
3489 if (t.hasTag(ARRAY)) {
3490 boundkind |= ARRAY_BOUND;
3491 } else {
3492 boundkind |= CLASS_BOUND;
3493 }
3494 break;
3495 default:
3496 if (t.isPrimitive())
3497 return syms.errType;
3498 }
3499 }
3500 switch (boundkind) {
3501 case 0:
3502 return syms.botType;
3504 case ARRAY_BOUND:
3505 // calculate lub(A[], B[])
3506 List<Type> elements = Type.map(ts, elemTypeFun);
3507 for (Type t : elements) {
3508 if (t.isPrimitive()) {
3509 // if a primitive type is found, then return
3510 // arraySuperType unless all the types are the
3511 // same
3512 Type first = ts.head;
3513 for (Type s : ts.tail) {
3514 if (!isSameType(first, s)) {
3515 // lub(int[], B[]) is Cloneable & Serializable
3516 return arraySuperType();
3517 }
3518 }
3519 // all the array types are the same, return one
3520 // lub(int[], int[]) is int[]
3521 return first;
3522 }
3523 }
3524 // lub(A[], B[]) is lub(A, B)[]
3525 return new ArrayType(lub(elements), syms.arrayClass);
3527 case CLASS_BOUND:
3528 // calculate lub(A, B)
3529 while (!ts.head.hasTag(CLASS) && !ts.head.hasTag(TYPEVAR)) {
3530 ts = ts.tail;
3531 }
3532 Assert.check(!ts.isEmpty());
3533 //step 1 - compute erased candidate set (EC)
3534 List<Type> cl = erasedSupertypes(ts.head);
3535 for (Type t : ts.tail) {
3536 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
3537 cl = intersect(cl, erasedSupertypes(t));
3538 }
3539 //step 2 - compute minimal erased candidate set (MEC)
3540 List<Type> mec = closureMin(cl);
3541 //step 3 - for each element G in MEC, compute lci(Inv(G))
3542 List<Type> candidates = List.nil();
3543 for (Type erasedSupertype : mec) {
3544 List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
3545 for (Type t : ts) {
3546 lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
3547 }
3548 candidates = candidates.appendList(lci);
3549 }
3550 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
3551 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
3552 return compoundMin(candidates);
3554 default:
3555 // calculate lub(A, B[])
3556 List<Type> classes = List.of(arraySuperType());
3557 for (Type t : ts) {
3558 if (!t.hasTag(ARRAY)) // Filter out any arrays
3559 classes = classes.prepend(t);
3560 }
3561 // lub(A, B[]) is lub(A, arraySuperType)
3562 return lub(classes);
3563 }
3564 }
3565 // where
3566 List<Type> erasedSupertypes(Type t) {
3567 ListBuffer<Type> buf = lb();
3568 for (Type sup : closure(t)) {
3569 if (sup.hasTag(TYPEVAR)) {
3570 buf.append(sup);
3571 } else {
3572 buf.append(erasure(sup));
3573 }
3574 }
3575 return buf.toList();
3576 }
3578 private Type arraySuperType = null;
3579 private Type arraySuperType() {
3580 // initialized lazily to avoid problems during compiler startup
3581 if (arraySuperType == null) {
3582 synchronized (this) {
3583 if (arraySuperType == null) {
3584 // JLS 10.8: all arrays implement Cloneable and Serializable.
3585 arraySuperType = makeCompoundType(List.of(syms.serializableType,
3586 syms.cloneableType), true);
3587 }
3588 }
3589 }
3590 return arraySuperType;
3591 }
3592 // </editor-fold>
3594 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
3595 public Type glb(List<Type> ts) {
3596 Type t1 = ts.head;
3597 for (Type t2 : ts.tail) {
3598 if (t1.isErroneous())
3599 return t1;
3600 t1 = glb(t1, t2);
3601 }
3602 return t1;
3603 }
3604 //where
3605 public Type glb(Type t, Type s) {
3606 if (s == null)
3607 return t;
3608 else if (t.isPrimitive() || s.isPrimitive())
3609 return syms.errType;
3610 else if (isSubtypeNoCapture(t, s))
3611 return t;
3612 else if (isSubtypeNoCapture(s, t))
3613 return s;
3615 List<Type> closure = union(closure(t), closure(s));
3616 List<Type> bounds = closureMin(closure);
3618 if (bounds.isEmpty()) { // length == 0
3619 return syms.objectType;
3620 } else if (bounds.tail.isEmpty()) { // length == 1
3621 return bounds.head;
3622 } else { // length > 1
3623 int classCount = 0;
3624 for (Type bound : bounds)
3625 if (!bound.isInterface())
3626 classCount++;
3627 if (classCount > 1)
3628 return createErrorType(t);
3629 }
3630 return makeCompoundType(bounds);
3631 }
3632 // </editor-fold>
3634 // <editor-fold defaultstate="collapsed" desc="hashCode">
3635 /**
3636 * Compute a hash code on a type.
3637 */
3638 public int hashCode(Type t) {
3639 return hashCode.visit(t);
3640 }
3641 // where
3642 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
3644 public Integer visitType(Type t, Void ignored) {
3645 return t.getTag().ordinal();
3646 }
3648 @Override
3649 public Integer visitClassType(ClassType t, Void ignored) {
3650 int result = visit(t.getEnclosingType());
3651 result *= 127;
3652 result += t.tsym.flatName().hashCode();
3653 for (Type s : t.getTypeArguments()) {
3654 result *= 127;
3655 result += visit(s);
3656 }
3657 return result;
3658 }
3660 @Override
3661 public Integer visitMethodType(MethodType t, Void ignored) {
3662 int h = METHOD.ordinal();
3663 for (List<Type> thisargs = t.argtypes;
3664 thisargs.tail != null;
3665 thisargs = thisargs.tail)
3666 h = (h << 5) + visit(thisargs.head);
3667 return (h << 5) + visit(t.restype);
3668 }
3670 @Override
3671 public Integer visitWildcardType(WildcardType t, Void ignored) {
3672 int result = t.kind.hashCode();
3673 if (t.type != null) {
3674 result *= 127;
3675 result += visit(t.type);
3676 }
3677 return result;
3678 }
3680 @Override
3681 public Integer visitArrayType(ArrayType t, Void ignored) {
3682 return visit(t.elemtype) + 12;
3683 }
3685 @Override
3686 public Integer visitTypeVar(TypeVar t, Void ignored) {
3687 return System.identityHashCode(t.tsym);
3688 }
3690 @Override
3691 public Integer visitUndetVar(UndetVar t, Void ignored) {
3692 return System.identityHashCode(t);
3693 }
3695 @Override
3696 public Integer visitErrorType(ErrorType t, Void ignored) {
3697 return 0;
3698 }
3699 };
3700 // </editor-fold>
3702 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
3703 /**
3704 * Does t have a result that is a subtype of the result type of s,
3705 * suitable for covariant returns? It is assumed that both types
3706 * are (possibly polymorphic) method types. Monomorphic method
3707 * types are handled in the obvious way. Polymorphic method types
3708 * require renaming all type variables of one to corresponding
3709 * type variables in the other, where correspondence is by
3710 * position in the type parameter list. */
3711 public boolean resultSubtype(Type t, Type s, Warner warner) {
3712 List<Type> tvars = t.getTypeArguments();
3713 List<Type> svars = s.getTypeArguments();
3714 Type tres = t.getReturnType();
3715 Type sres = subst(s.getReturnType(), svars, tvars);
3716 return covariantReturnType(tres, sres, warner);
3717 }
3719 /**
3720 * Return-Type-Substitutable.
3721 * @jls section 8.4.5
3722 */
3723 public boolean returnTypeSubstitutable(Type r1, Type r2) {
3724 if (hasSameArgs(r1, r2))
3725 return resultSubtype(r1, r2, noWarnings);
3726 else
3727 return covariantReturnType(r1.getReturnType(),
3728 erasure(r2.getReturnType()),
3729 noWarnings);
3730 }
3732 public boolean returnTypeSubstitutable(Type r1,
3733 Type r2, Type r2res,
3734 Warner warner) {
3735 if (isSameType(r1.getReturnType(), r2res))
3736 return true;
3737 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
3738 return false;
3740 if (hasSameArgs(r1, r2))
3741 return covariantReturnType(r1.getReturnType(), r2res, warner);
3742 if (!allowCovariantReturns)
3743 return false;
3744 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
3745 return true;
3746 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
3747 return false;
3748 warner.warn(LintCategory.UNCHECKED);
3749 return true;
3750 }
3752 /**
3753 * Is t an appropriate return type in an overrider for a
3754 * method that returns s?
3755 */
3756 public boolean covariantReturnType(Type t, Type s, Warner warner) {
3757 return
3758 isSameType(t, s) ||
3759 allowCovariantReturns &&
3760 !t.isPrimitive() &&
3761 !s.isPrimitive() &&
3762 isAssignable(t, s, warner);
3763 }
3764 // </editor-fold>
3766 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3767 /**
3768 * Return the class that boxes the given primitive.
3769 */
3770 public ClassSymbol boxedClass(Type t) {
3771 return reader.enterClass(syms.boxedName[t.getTag().ordinal()]);
3772 }
3774 /**
3775 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3776 */
3777 public Type boxedTypeOrType(Type t) {
3778 return t.isPrimitive() ?
3779 boxedClass(t).type :
3780 t;
3781 }
3783 /**
3784 * Return the primitive type corresponding to a boxed type.
3785 */
3786 public Type unboxedType(Type t) {
3787 if (allowBoxing) {
3788 for (int i=0; i<syms.boxedName.length; i++) {
3789 Name box = syms.boxedName[i];
3790 if (box != null &&
3791 asSuper(t, reader.enterClass(box)) != null)
3792 return syms.typeOfTag[i];
3793 }
3794 }
3795 return Type.noType;
3796 }
3798 /**
3799 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
3800 */
3801 public Type unboxedTypeOrType(Type t) {
3802 Type unboxedType = unboxedType(t);
3803 return unboxedType.hasTag(NONE) ? t : unboxedType;
3804 }
3805 // </editor-fold>
3807 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3808 /*
3809 * JLS 5.1.10 Capture Conversion:
3810 *
3811 * Let G name a generic type declaration with n formal type
3812 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3813 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3814 * where, for 1 <= i <= n:
3815 *
3816 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3817 * Si is a fresh type variable whose upper bound is
3818 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3819 * type.
3820 *
3821 * + If Ti is a wildcard type argument of the form ? extends Bi,
3822 * then Si is a fresh type variable whose upper bound is
3823 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3824 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3825 * a compile-time error if for any two classes (not interfaces)
3826 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3827 *
3828 * + If Ti is a wildcard type argument of the form ? super Bi,
3829 * then Si is a fresh type variable whose upper bound is
3830 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3831 *
3832 * + Otherwise, Si = Ti.
3833 *
3834 * Capture conversion on any type other than a parameterized type
3835 * (4.5) acts as an identity conversion (5.1.1). Capture
3836 * conversions never require a special action at run time and
3837 * therefore never throw an exception at run time.
3838 *
3839 * Capture conversion is not applied recursively.
3840 */
3841 /**
3842 * Capture conversion as specified by the JLS.
3843 */
3845 public List<Type> capture(List<Type> ts) {
3846 List<Type> buf = List.nil();
3847 for (Type t : ts) {
3848 buf = buf.prepend(capture(t));
3849 }
3850 return buf.reverse();
3851 }
3852 public Type capture(Type t) {
3853 if (!t.hasTag(CLASS))
3854 return t;
3855 if (t.getEnclosingType() != Type.noType) {
3856 Type capturedEncl = capture(t.getEnclosingType());
3857 if (capturedEncl != t.getEnclosingType()) {
3858 Type type1 = memberType(capturedEncl, t.tsym);
3859 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3860 }
3861 }
3862 t = t.unannotatedType();
3863 ClassType cls = (ClassType)t;
3864 if (cls.isRaw() || !cls.isParameterized())
3865 return cls;
3867 ClassType G = (ClassType)cls.asElement().asType();
3868 List<Type> A = G.getTypeArguments();
3869 List<Type> T = cls.getTypeArguments();
3870 List<Type> S = freshTypeVariables(T);
3872 List<Type> currentA = A;
3873 List<Type> currentT = T;
3874 List<Type> currentS = S;
3875 boolean captured = false;
3876 while (!currentA.isEmpty() &&
3877 !currentT.isEmpty() &&
3878 !currentS.isEmpty()) {
3879 if (currentS.head != currentT.head) {
3880 captured = true;
3881 WildcardType Ti = (WildcardType)currentT.head.unannotatedType();
3882 Type Ui = currentA.head.getUpperBound();
3883 CapturedType Si = (CapturedType)currentS.head.unannotatedType();
3884 if (Ui == null)
3885 Ui = syms.objectType;
3886 switch (Ti.kind) {
3887 case UNBOUND:
3888 Si.bound = subst(Ui, A, S);
3889 Si.lower = syms.botType;
3890 break;
3891 case EXTENDS:
3892 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3893 Si.lower = syms.botType;
3894 break;
3895 case SUPER:
3896 Si.bound = subst(Ui, A, S);
3897 Si.lower = Ti.getSuperBound();
3898 break;
3899 }
3900 if (Si.bound == Si.lower)
3901 currentS.head = Si.bound;
3902 }
3903 currentA = currentA.tail;
3904 currentT = currentT.tail;
3905 currentS = currentS.tail;
3906 }
3907 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3908 return erasure(t); // some "rare" type involved
3910 if (captured)
3911 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3912 else
3913 return t;
3914 }
3915 // where
3916 public List<Type> freshTypeVariables(List<Type> types) {
3917 ListBuffer<Type> result = lb();
3918 for (Type t : types) {
3919 if (t.hasTag(WILDCARD)) {
3920 t = t.unannotatedType();
3921 Type bound = ((WildcardType)t).getExtendsBound();
3922 if (bound == null)
3923 bound = syms.objectType;
3924 result.append(new CapturedType(capturedName,
3925 syms.noSymbol,
3926 bound,
3927 syms.botType,
3928 (WildcardType)t));
3929 } else {
3930 result.append(t);
3931 }
3932 }
3933 return result.toList();
3934 }
3935 // </editor-fold>
3937 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3938 private List<Type> upperBounds(List<Type> ss) {
3939 if (ss.isEmpty()) return ss;
3940 Type head = upperBound(ss.head);
3941 List<Type> tail = upperBounds(ss.tail);
3942 if (head != ss.head || tail != ss.tail)
3943 return tail.prepend(head);
3944 else
3945 return ss;
3946 }
3948 private boolean sideCast(Type from, Type to, Warner warn) {
3949 // We are casting from type $from$ to type $to$, which are
3950 // non-final unrelated types. This method
3951 // tries to reject a cast by transferring type parameters
3952 // from $to$ to $from$ by common superinterfaces.
3953 boolean reverse = false;
3954 Type target = to;
3955 if ((to.tsym.flags() & INTERFACE) == 0) {
3956 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3957 reverse = true;
3958 to = from;
3959 from = target;
3960 }
3961 List<Type> commonSupers = superClosure(to, erasure(from));
3962 boolean giveWarning = commonSupers.isEmpty();
3963 // The arguments to the supers could be unified here to
3964 // get a more accurate analysis
3965 while (commonSupers.nonEmpty()) {
3966 Type t1 = asSuper(from, commonSupers.head.tsym);
3967 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3968 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3969 return false;
3970 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3971 commonSupers = commonSupers.tail;
3972 }
3973 if (giveWarning && !isReifiable(reverse ? from : to))
3974 warn.warn(LintCategory.UNCHECKED);
3975 if (!allowCovariantReturns)
3976 // reject if there is a common method signature with
3977 // incompatible return types.
3978 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3979 return true;
3980 }
3982 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3983 // We are casting from type $from$ to type $to$, which are
3984 // unrelated types one of which is final and the other of
3985 // which is an interface. This method
3986 // tries to reject a cast by transferring type parameters
3987 // from the final class to the interface.
3988 boolean reverse = false;
3989 Type target = to;
3990 if ((to.tsym.flags() & INTERFACE) == 0) {
3991 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3992 reverse = true;
3993 to = from;
3994 from = target;
3995 }
3996 Assert.check((from.tsym.flags() & FINAL) != 0);
3997 Type t1 = asSuper(from, to.tsym);
3998 if (t1 == null) return false;
3999 Type t2 = to;
4000 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4001 return false;
4002 if (!allowCovariantReturns)
4003 // reject if there is a common method signature with
4004 // incompatible return types.
4005 chk.checkCompatibleAbstracts(warn.pos(), from, to);
4006 if (!isReifiable(target) &&
4007 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
4008 warn.warn(LintCategory.UNCHECKED);
4009 return true;
4010 }
4012 private boolean giveWarning(Type from, Type to) {
4013 List<Type> bounds = to.isCompound() ?
4014 ((IntersectionClassType)to.unannotatedType()).getComponents() : List.of(to);
4015 for (Type b : bounds) {
4016 Type subFrom = asSub(from, b.tsym);
4017 if (b.isParameterized() &&
4018 (!(isUnbounded(b) ||
4019 isSubtype(from, b) ||
4020 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
4021 return true;
4022 }
4023 }
4024 return false;
4025 }
4027 private List<Type> superClosure(Type t, Type s) {
4028 List<Type> cl = List.nil();
4029 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
4030 if (isSubtype(s, erasure(l.head))) {
4031 cl = insert(cl, l.head);
4032 } else {
4033 cl = union(cl, superClosure(l.head, s));
4034 }
4035 }
4036 return cl;
4037 }
4039 private boolean containsTypeEquivalent(Type t, Type s) {
4040 return
4041 isSameType(t, s) || // shortcut
4042 containsType(t, s) && containsType(s, t);
4043 }
4045 // <editor-fold defaultstate="collapsed" desc="adapt">
4046 /**
4047 * Adapt a type by computing a substitution which maps a source
4048 * type to a target type.
4049 *
4050 * @param source the source type
4051 * @param target the target type
4052 * @param from the type variables of the computed substitution
4053 * @param to the types of the computed substitution.
4054 */
4055 public void adapt(Type source,
4056 Type target,
4057 ListBuffer<Type> from,
4058 ListBuffer<Type> to) throws AdaptFailure {
4059 new Adapter(from, to).adapt(source, target);
4060 }
4062 class Adapter extends SimpleVisitor<Void, Type> {
4064 ListBuffer<Type> from;
4065 ListBuffer<Type> to;
4066 Map<Symbol,Type> mapping;
4068 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
4069 this.from = from;
4070 this.to = to;
4071 mapping = new HashMap<Symbol,Type>();
4072 }
4074 public void adapt(Type source, Type target) throws AdaptFailure {
4075 visit(source, target);
4076 List<Type> fromList = from.toList();
4077 List<Type> toList = to.toList();
4078 while (!fromList.isEmpty()) {
4079 Type val = mapping.get(fromList.head.tsym);
4080 if (toList.head != val)
4081 toList.head = val;
4082 fromList = fromList.tail;
4083 toList = toList.tail;
4084 }
4085 }
4087 @Override
4088 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
4089 if (target.hasTag(CLASS))
4090 adaptRecursive(source.allparams(), target.allparams());
4091 return null;
4092 }
4094 @Override
4095 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
4096 if (target.hasTag(ARRAY))
4097 adaptRecursive(elemtype(source), elemtype(target));
4098 return null;
4099 }
4101 @Override
4102 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
4103 if (source.isExtendsBound())
4104 adaptRecursive(upperBound(source), upperBound(target));
4105 else if (source.isSuperBound())
4106 adaptRecursive(lowerBound(source), lowerBound(target));
4107 return null;
4108 }
4110 @Override
4111 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
4112 // Check to see if there is
4113 // already a mapping for $source$, in which case
4114 // the old mapping will be merged with the new
4115 Type val = mapping.get(source.tsym);
4116 if (val != null) {
4117 if (val.isSuperBound() && target.isSuperBound()) {
4118 val = isSubtype(lowerBound(val), lowerBound(target))
4119 ? target : val;
4120 } else if (val.isExtendsBound() && target.isExtendsBound()) {
4121 val = isSubtype(upperBound(val), upperBound(target))
4122 ? val : target;
4123 } else if (!isSameType(val, target)) {
4124 throw new AdaptFailure();
4125 }
4126 } else {
4127 val = target;
4128 from.append(source);
4129 to.append(target);
4130 }
4131 mapping.put(source.tsym, val);
4132 return null;
4133 }
4135 @Override
4136 public Void visitType(Type source, Type target) {
4137 return null;
4138 }
4140 private Set<TypePair> cache = new HashSet<TypePair>();
4142 private void adaptRecursive(Type source, Type target) {
4143 TypePair pair = new TypePair(source, target);
4144 if (cache.add(pair)) {
4145 try {
4146 visit(source, target);
4147 } finally {
4148 cache.remove(pair);
4149 }
4150 }
4151 }
4153 private void adaptRecursive(List<Type> source, List<Type> target) {
4154 if (source.length() == target.length()) {
4155 while (source.nonEmpty()) {
4156 adaptRecursive(source.head, target.head);
4157 source = source.tail;
4158 target = target.tail;
4159 }
4160 }
4161 }
4162 }
4164 public static class AdaptFailure extends RuntimeException {
4165 static final long serialVersionUID = -7490231548272701566L;
4166 }
4168 private void adaptSelf(Type t,
4169 ListBuffer<Type> from,
4170 ListBuffer<Type> to) {
4171 try {
4172 //if (t.tsym.type != t)
4173 adapt(t.tsym.type, t, from, to);
4174 } catch (AdaptFailure ex) {
4175 // Adapt should never fail calculating a mapping from
4176 // t.tsym.type to t as there can be no merge problem.
4177 throw new AssertionError(ex);
4178 }
4179 }
4180 // </editor-fold>
4182 /**
4183 * Rewrite all type variables (universal quantifiers) in the given
4184 * type to wildcards (existential quantifiers). This is used to
4185 * determine if a cast is allowed. For example, if high is true
4186 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4187 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4188 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4189 * List<Integer>} with a warning.
4190 * @param t a type
4191 * @param high if true return an upper bound; otherwise a lower
4192 * bound
4193 * @param rewriteTypeVars only rewrite captured wildcards if false;
4194 * otherwise rewrite all type variables
4195 * @return the type rewritten with wildcards (existential
4196 * quantifiers) only
4197 */
4198 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4199 return new Rewriter(high, rewriteTypeVars).visit(t);
4200 }
4202 class Rewriter extends UnaryVisitor<Type> {
4204 boolean high;
4205 boolean rewriteTypeVars;
4207 Rewriter(boolean high, boolean rewriteTypeVars) {
4208 this.high = high;
4209 this.rewriteTypeVars = rewriteTypeVars;
4210 }
4212 @Override
4213 public Type visitClassType(ClassType t, Void s) {
4214 ListBuffer<Type> rewritten = new ListBuffer<Type>();
4215 boolean changed = false;
4216 for (Type arg : t.allparams()) {
4217 Type bound = visit(arg);
4218 if (arg != bound) {
4219 changed = true;
4220 }
4221 rewritten.append(bound);
4222 }
4223 if (changed)
4224 return subst(t.tsym.type,
4225 t.tsym.type.allparams(),
4226 rewritten.toList());
4227 else
4228 return t;
4229 }
4231 public Type visitType(Type t, Void s) {
4232 return high ? upperBound(t) : lowerBound(t);
4233 }
4235 @Override
4236 public Type visitCapturedType(CapturedType t, Void s) {
4237 Type w_bound = t.wildcard.type;
4238 Type bound = w_bound.contains(t) ?
4239 erasure(w_bound) :
4240 visit(w_bound);
4241 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4242 }
4244 @Override
4245 public Type visitTypeVar(TypeVar t, Void s) {
4246 if (rewriteTypeVars) {
4247 Type bound = t.bound.contains(t) ?
4248 erasure(t.bound) :
4249 visit(t.bound);
4250 return rewriteAsWildcardType(bound, t, EXTENDS);
4251 } else {
4252 return t;
4253 }
4254 }
4256 @Override
4257 public Type visitWildcardType(WildcardType t, Void s) {
4258 Type bound2 = visit(t.type);
4259 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4260 }
4262 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4263 switch (bk) {
4264 case EXTENDS: return high ?
4265 makeExtendsWildcard(B(bound), formal) :
4266 makeExtendsWildcard(syms.objectType, formal);
4267 case SUPER: return high ?
4268 makeSuperWildcard(syms.botType, formal) :
4269 makeSuperWildcard(B(bound), formal);
4270 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4271 default:
4272 Assert.error("Invalid bound kind " + bk);
4273 return null;
4274 }
4275 }
4277 Type B(Type t) {
4278 while (t.hasTag(WILDCARD)) {
4279 WildcardType w = (WildcardType)t.unannotatedType();
4280 t = high ?
4281 w.getExtendsBound() :
4282 w.getSuperBound();
4283 if (t == null) {
4284 t = high ? syms.objectType : syms.botType;
4285 }
4286 }
4287 return t;
4288 }
4289 }
4292 /**
4293 * Create a wildcard with the given upper (extends) bound; create
4294 * an unbounded wildcard if bound is Object.
4295 *
4296 * @param bound the upper bound
4297 * @param formal the formal type parameter that will be
4298 * substituted by the wildcard
4299 */
4300 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4301 if (bound == syms.objectType) {
4302 return new WildcardType(syms.objectType,
4303 BoundKind.UNBOUND,
4304 syms.boundClass,
4305 formal);
4306 } else {
4307 return new WildcardType(bound,
4308 BoundKind.EXTENDS,
4309 syms.boundClass,
4310 formal);
4311 }
4312 }
4314 /**
4315 * Create a wildcard with the given lower (super) bound; create an
4316 * unbounded wildcard if bound is bottom (type of {@code null}).
4317 *
4318 * @param bound the lower bound
4319 * @param formal the formal type parameter that will be
4320 * substituted by the wildcard
4321 */
4322 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4323 if (bound.hasTag(BOT)) {
4324 return new WildcardType(syms.objectType,
4325 BoundKind.UNBOUND,
4326 syms.boundClass,
4327 formal);
4328 } else {
4329 return new WildcardType(bound,
4330 BoundKind.SUPER,
4331 syms.boundClass,
4332 formal);
4333 }
4334 }
4336 /**
4337 * A wrapper for a type that allows use in sets.
4338 */
4339 public static class UniqueType {
4340 public final Type type;
4341 final Types types;
4343 public UniqueType(Type type, Types types) {
4344 this.type = type;
4345 this.types = types;
4346 }
4348 public int hashCode() {
4349 return types.hashCode(type);
4350 }
4352 public boolean equals(Object obj) {
4353 return (obj instanceof UniqueType) &&
4354 types.isSameAnnotatedType(type, ((UniqueType)obj).type);
4355 }
4357 public String toString() {
4358 return type.toString();
4359 }
4361 }
4362 // </editor-fold>
4364 // <editor-fold defaultstate="collapsed" desc="Visitors">
4365 /**
4366 * A default visitor for types. All visitor methods except
4367 * visitType are implemented by delegating to visitType. Concrete
4368 * subclasses must provide an implementation of visitType and can
4369 * override other methods as needed.
4370 *
4371 * @param <R> the return type of the operation implemented by this
4372 * visitor; use Void if no return type is needed.
4373 * @param <S> the type of the second argument (the first being the
4374 * type itself) of the operation implemented by this visitor; use
4375 * Void if a second argument is not needed.
4376 */
4377 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4378 final public R visit(Type t, S s) { return t.accept(this, s); }
4379 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4380 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4381 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4382 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4383 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4384 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4385 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4386 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4387 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4388 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4389 // Pretend annotations don't exist
4390 public R visitAnnotatedType(AnnotatedType t, S s) { return visit(t.underlyingType, s); }
4391 }
4393 /**
4394 * A default visitor for symbols. All visitor methods except
4395 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4396 * subclasses must provide an implementation of visitSymbol and can
4397 * override other methods as needed.
4398 *
4399 * @param <R> the return type of the operation implemented by this
4400 * visitor; use Void if no return type is needed.
4401 * @param <S> the type of the second argument (the first being the
4402 * symbol itself) of the operation implemented by this visitor; use
4403 * Void if a second argument is not needed.
4404 */
4405 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4406 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
4407 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4408 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4409 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4410 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4411 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4412 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4413 }
4415 /**
4416 * A <em>simple</em> visitor for types. This visitor is simple as
4417 * captured wildcards, for-all types (generic methods), and
4418 * undetermined type variables (part of inference) are hidden.
4419 * Captured wildcards are hidden by treating them as type
4420 * variables and the rest are hidden by visiting their qtypes.
4421 *
4422 * @param <R> the return type of the operation implemented by this
4423 * visitor; use Void if no return type is needed.
4424 * @param <S> the type of the second argument (the first being the
4425 * type itself) of the operation implemented by this visitor; use
4426 * Void if a second argument is not needed.
4427 */
4428 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4429 @Override
4430 public R visitCapturedType(CapturedType t, S s) {
4431 return visitTypeVar(t, s);
4432 }
4433 @Override
4434 public R visitForAll(ForAll t, S s) {
4435 return visit(t.qtype, s);
4436 }
4437 @Override
4438 public R visitUndetVar(UndetVar t, S s) {
4439 return visit(t.qtype, s);
4440 }
4441 }
4443 /**
4444 * A plain relation on types. That is a 2-ary function on the
4445 * form Type × Type → Boolean.
4446 * <!-- In plain text: Type x Type -> Boolean -->
4447 */
4448 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4450 /**
4451 * A convenience visitor for implementing operations that only
4452 * require one argument (the type itself), that is, unary
4453 * operations.
4454 *
4455 * @param <R> the return type of the operation implemented by this
4456 * visitor; use Void if no return type is needed.
4457 */
4458 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4459 final public R visit(Type t) { return t.accept(this, null); }
4460 }
4462 /**
4463 * A visitor for implementing a mapping from types to types. The
4464 * default behavior of this class is to implement the identity
4465 * mapping (mapping a type to itself). This can be overridden in
4466 * subclasses.
4467 *
4468 * @param <S> the type of the second argument (the first being the
4469 * type itself) of this mapping; use Void if a second argument is
4470 * not needed.
4471 */
4472 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4473 final public Type visit(Type t) { return t.accept(this, null); }
4474 public Type visitType(Type t, S s) { return t; }
4475 }
4476 // </editor-fold>
4479 // <editor-fold defaultstate="collapsed" desc="Annotation support">
4481 public RetentionPolicy getRetention(Attribute.Compound a) {
4482 return getRetention(a.type.tsym);
4483 }
4485 public RetentionPolicy getRetention(Symbol sym) {
4486 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
4487 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
4488 if (c != null) {
4489 Attribute value = c.member(names.value);
4490 if (value != null && value instanceof Attribute.Enum) {
4491 Name levelName = ((Attribute.Enum)value).value.name;
4492 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
4493 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
4494 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
4495 else ;// /* fail soft */ throw new AssertionError(levelName);
4496 }
4497 }
4498 return vis;
4499 }
4500 // </editor-fold>
4502 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
4504 public static abstract class SignatureGenerator {
4506 private final Types types;
4508 protected abstract void append(char ch);
4509 protected abstract void append(byte[] ba);
4510 protected abstract void append(Name name);
4511 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
4513 protected SignatureGenerator(Types types) {
4514 this.types = types;
4515 }
4517 /**
4518 * Assemble signature of given type in string buffer.
4519 */
4520 public void assembleSig(Type type) {
4521 type = type.unannotatedType();
4522 switch (type.getTag()) {
4523 case BYTE:
4524 append('B');
4525 break;
4526 case SHORT:
4527 append('S');
4528 break;
4529 case CHAR:
4530 append('C');
4531 break;
4532 case INT:
4533 append('I');
4534 break;
4535 case LONG:
4536 append('J');
4537 break;
4538 case FLOAT:
4539 append('F');
4540 break;
4541 case DOUBLE:
4542 append('D');
4543 break;
4544 case BOOLEAN:
4545 append('Z');
4546 break;
4547 case VOID:
4548 append('V');
4549 break;
4550 case CLASS:
4551 append('L');
4552 assembleClassSig(type);
4553 append(';');
4554 break;
4555 case ARRAY:
4556 ArrayType at = (ArrayType) type;
4557 append('[');
4558 assembleSig(at.elemtype);
4559 break;
4560 case METHOD:
4561 MethodType mt = (MethodType) type;
4562 append('(');
4563 assembleSig(mt.argtypes);
4564 append(')');
4565 assembleSig(mt.restype);
4566 if (hasTypeVar(mt.thrown)) {
4567 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
4568 append('^');
4569 assembleSig(l.head);
4570 }
4571 }
4572 break;
4573 case WILDCARD: {
4574 Type.WildcardType ta = (Type.WildcardType) type;
4575 switch (ta.kind) {
4576 case SUPER:
4577 append('-');
4578 assembleSig(ta.type);
4579 break;
4580 case EXTENDS:
4581 append('+');
4582 assembleSig(ta.type);
4583 break;
4584 case UNBOUND:
4585 append('*');
4586 break;
4587 default:
4588 throw new AssertionError(ta.kind);
4589 }
4590 break;
4591 }
4592 case TYPEVAR:
4593 append('T');
4594 append(type.tsym.name);
4595 append(';');
4596 break;
4597 case FORALL:
4598 Type.ForAll ft = (Type.ForAll) type;
4599 assembleParamsSig(ft.tvars);
4600 assembleSig(ft.qtype);
4601 break;
4602 default:
4603 throw new AssertionError("typeSig " + type.getTag());
4604 }
4605 }
4607 public boolean hasTypeVar(List<Type> l) {
4608 while (l.nonEmpty()) {
4609 if (l.head.hasTag(TypeTag.TYPEVAR)) {
4610 return true;
4611 }
4612 l = l.tail;
4613 }
4614 return false;
4615 }
4617 public void assembleClassSig(Type type) {
4618 type = type.unannotatedType();
4619 ClassType ct = (ClassType) type;
4620 ClassSymbol c = (ClassSymbol) ct.tsym;
4621 classReference(c);
4622 Type outer = ct.getEnclosingType();
4623 if (outer.allparams().nonEmpty()) {
4624 boolean rawOuter =
4625 c.owner.kind == Kinds.MTH || // either a local class
4626 c.name == types.names.empty; // or anonymous
4627 assembleClassSig(rawOuter
4628 ? types.erasure(outer)
4629 : outer);
4630 append('.');
4631 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
4632 append(rawOuter
4633 ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength())
4634 : c.name);
4635 } else {
4636 append(externalize(c.flatname));
4637 }
4638 if (ct.getTypeArguments().nonEmpty()) {
4639 append('<');
4640 assembleSig(ct.getTypeArguments());
4641 append('>');
4642 }
4643 }
4645 public void assembleParamsSig(List<Type> typarams) {
4646 append('<');
4647 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
4648 Type.TypeVar tvar = (Type.TypeVar) ts.head;
4649 append(tvar.tsym.name);
4650 List<Type> bounds = types.getBounds(tvar);
4651 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
4652 append(':');
4653 }
4654 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
4655 append(':');
4656 assembleSig(l.head);
4657 }
4658 }
4659 append('>');
4660 }
4662 private void assembleSig(List<Type> types) {
4663 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
4664 assembleSig(ts.head);
4665 }
4666 }
4667 }
4668 // </editor-fold>
4669 }
