1 /*
2 * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.tools.javac.code;
27
28 import java.lang.ref.SoftReference;
29 import java.util.HashSet;
30 import java.util.HashMap;
31 import java.util.Locale;
32 import java.util.Map;
33 import java.util.Optional;
34 import java.util.Set;
35 import java.util.WeakHashMap;
36 import java.util.function.BiFunction;
37 import java.util.function.BiPredicate;
38 import java.util.function.Function;
39 import java.util.function.Predicate;
40 import java.util.stream.Collector;
41
42 import javax.tools.JavaFileObject;
43
44 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
45 import com.sun.tools.javac.code.Lint.LintCategory;
46 import com.sun.tools.javac.code.Source.Feature;
47 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
48 import com.sun.tools.javac.code.TypeMetadata.Annotations;
49 import com.sun.tools.javac.comp.AttrContext;
50 import com.sun.tools.javac.comp.Check;
51 import com.sun.tools.javac.comp.Enter;
52 import com.sun.tools.javac.comp.Env;
53 import com.sun.tools.javac.jvm.ClassFile;
54 import com.sun.tools.javac.util.*;
55
56 import static com.sun.tools.javac.code.BoundKind.*;
57 import static com.sun.tools.javac.code.Flags.*;
58 import static com.sun.tools.javac.code.Kinds.Kind.*;
59 import static com.sun.tools.javac.code.Scope.*;
60 import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
61 import static com.sun.tools.javac.code.Symbol.*;
62 import static com.sun.tools.javac.code.Type.*;
63 import static com.sun.tools.javac.code.TypeTag.*;
64 import static com.sun.tools.javac.jvm.ClassFile.externalize;
65 import static com.sun.tools.javac.main.Option.DOE;
66
67 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
68
69 /**
70 * Utility class containing various operations on types.
71 *
72 * <p>Unless other names are more illustrative, the following naming
73 * conventions should be observed in this file:
74 *
75 * <dl>
76 * <dt>t</dt>
77 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
78 * <dt>s</dt>
79 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
80 * <dt>ts</dt>
81 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
82 * <dt>ss</dt>
83 * <dd>A second list of types should be named ss.</dd>
84 * </dl>
85 *
86 * <p><b>This is NOT part of any supported API.
87 * If you write code that depends on this, you do so at your own risk.
88 * This code and its internal interfaces are subject to change or
89 * deletion without notice.</b>
90 */
91 public class Types {
92 protected static final Context.Key<Types> typesKey = new Context.Key<>();
93
94 final Symtab syms;
95 final JavacMessages messages;
96 final Names names;
97 final Check chk;
98 final Enter enter;
99 JCDiagnostic.Factory diags;
100 List<Warner> warnStack = List.nil();
101 final Name capturedName;
102
103 public final Warner noWarnings;
104 public final boolean dumpStacktraceOnError;
105
106 // <editor-fold defaultstate="collapsed" desc="Instantiating">
107 public static Types instance(Context context) {
108 Types instance = context.get(typesKey);
109 if (instance == null)
110 instance = new Types(context);
111 return instance;
112 }
113
114 @SuppressWarnings("this-escape")
115 protected Types(Context context) {
116 context.put(typesKey, this);
117 syms = Symtab.instance(context);
118 names = Names.instance(context);
119 Source source = Source.instance(context);
120 chk = Check.instance(context);
121 enter = Enter.instance(context);
122 capturedName = names.fromString("<captured wildcard>");
123 messages = JavacMessages.instance(context);
124 diags = JCDiagnostic.Factory.instance(context);
125 noWarnings = new Warner(null) {
126 @Override
127 public String toString() {
128 return "NO_WARNINGS";
129 }
130 };
131 Options options = Options.instance(context);
132 dumpStacktraceOnError = options.isSet("dev") || options.isSet(DOE);
133 }
134 // </editor-fold>
135
136 // <editor-fold defaultstate="collapsed" desc="bounds">
137 /**
138 * Get a wildcard's upper bound, returning non-wildcards unchanged.
139 * @param t a type argument, either a wildcard or a type
140 */
141 public Type wildUpperBound(Type t) {
142 if (t.hasTag(WILDCARD)) {
143 WildcardType w = (WildcardType) t;
144 if (w.isSuperBound())
145 return w.bound == null ? syms.objectType : w.bound.getUpperBound();
146 else
147 return wildUpperBound(w.type);
148 }
149 else return t;
150 }
151
152 /**
153 * Get a capture variable's upper bound, returning other types unchanged.
154 * @param t a type
155 */
156 public Type cvarUpperBound(Type t) {
157 if (t.hasTag(TYPEVAR)) {
158 TypeVar v = (TypeVar) t;
159 return v.isCaptured() ? cvarUpperBound(v.getUpperBound()) : v;
160 }
161 else return t;
162 }
163
164 /**
165 * Get a wildcard's lower bound, returning non-wildcards unchanged.
166 * @param t a type argument, either a wildcard or a type
167 */
168 public Type wildLowerBound(Type t) {
169 if (t.hasTag(WILDCARD)) {
170 WildcardType w = (WildcardType) t;
171 return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type);
172 }
173 else return t;
174 }
175
176 /**
177 * Get a capture variable's lower bound, returning other types unchanged.
178 * @param t a type
179 */
180 public Type cvarLowerBound(Type t) {
181 if (t.hasTag(TYPEVAR) && ((TypeVar) t).isCaptured()) {
182 return cvarLowerBound(t.getLowerBound());
183 }
184 else return t;
185 }
186
187 /**
188 * Recursively skip type-variables until a class/array type is found; capture conversion is then
189 * (optionally) applied to the resulting type. This is useful for i.e. computing a site that is
190 * suitable for a method lookup.
191 */
192 public Type skipTypeVars(Type site, boolean capture) {
193 while (site.hasTag(TYPEVAR)) {
194 site = site.getUpperBound();
195 }
196 return capture ? capture(site) : site;
197 }
198 // </editor-fold>
199
200 // <editor-fold defaultstate="collapsed" desc="projections">
201
202 /**
203 * A projection kind. See {@link TypeProjection}
204 */
205 enum ProjectionKind {
206 UPWARDS() {
207 @Override
208 ProjectionKind complement() {
209 return DOWNWARDS;
210 }
211 },
212 DOWNWARDS() {
213 @Override
214 ProjectionKind complement() {
215 return UPWARDS;
216 }
217 };
218
219 abstract ProjectionKind complement();
220 }
221
222 /**
223 * This visitor performs upwards and downwards projections on types.
224 *
225 * A projection is defined as a function that takes a type T, a set of type variables V and that
226 * produces another type S.
227 *
228 * An upwards projection maps a type T into a type S such that (i) T has no variables in V,
229 * and (ii) S is an upper bound of T.
230 *
231 * A downwards projection maps a type T into a type S such that (i) T has no variables in V,
232 * and (ii) S is a lower bound of T.
233 *
234 * Note that projections are only allowed to touch variables in V. Therefore, it is possible for
235 * a projection to leave its input type unchanged if it does not contain any variables in V.
236 *
237 * Moreover, note that while an upwards projection is always defined (every type as an upper bound),
238 * a downwards projection is not always defined.
239 *
240 * Examples:
241 *
242 * {@code upwards(List<#CAP1>, [#CAP1]) = List<? extends String>, where #CAP1 <: String }
243 * {@code downwards(List<#CAP2>, [#CAP2]) = List<? super String>, where #CAP2 :> String }
244 * {@code upwards(List<#CAP1>, [#CAP2]) = List<#CAP1> }
245 * {@code downwards(List<#CAP1>, [#CAP1]) = not defined }
246 */
247 class TypeProjection extends TypeMapping<ProjectionKind> {
248
249 List<Type> vars;
250 Set<Type> seen = new HashSet<>();
251
252 public TypeProjection(List<Type> vars) {
253 this.vars = vars;
254 }
255
256 @Override
257 public Type visitClassType(ClassType t, ProjectionKind pkind) {
258 if (t.isCompound()) {
259 List<Type> components = directSupertypes(t);
260 List<Type> components1 = components.map(c -> c.map(this, pkind));
261 if (components == components1) return t;
262 else return makeIntersectionType(components1);
263 } else {
264 Type outer = t.getEnclosingType();
265 Type outer1 = visit(outer, pkind);
266 List<Type> typarams = t.getTypeArguments();
267 List<Type> formals = t.tsym.type.getTypeArguments();
268 ListBuffer<Type> typarams1 = new ListBuffer<>();
269 boolean changed = false;
270 for (Type actual : typarams) {
271 Type t2 = mapTypeArgument(t, formals.head.getUpperBound(), actual, pkind);
272 if (t2.hasTag(BOT)) {
273 //not defined
274 return syms.botType;
275 }
276 typarams1.add(t2);
277 changed |= actual != t2;
278 formals = formals.tail;
279 }
280 if (outer1 == outer && !changed) return t;
281 else return new ClassType(outer1, typarams1.toList(), t.tsym, t.getMetadata()) {
282 @Override
283 protected boolean needsStripping() {
284 return true;
285 }
286 };
287 }
288 }
289
290 @Override
291 public Type visitArrayType(ArrayType t, ProjectionKind s) {
292 Type elemtype = t.elemtype;
293 Type elemtype1 = visit(elemtype, s);
294 if (elemtype1 == elemtype) {
295 return t;
296 } else if (elemtype1.hasTag(BOT)) {
297 //undefined
298 return syms.botType;
299 } else {
300 return new ArrayType(elemtype1, t.tsym, t.metadata) {
301 @Override
302 protected boolean needsStripping() {
303 return true;
304 }
305 };
306 }
307 }
308
309 @Override
310 public Type visitTypeVar(TypeVar t, ProjectionKind pkind) {
311 if (vars.contains(t)) {
312 if (seen.add(t)) {
313 try {
314 final Type bound;
315 switch (pkind) {
316 case UPWARDS:
317 bound = t.getUpperBound();
318 break;
319 case DOWNWARDS:
320 bound = (t.getLowerBound() == null) ?
321 syms.botType :
322 t.getLowerBound();
323 break;
324 default:
325 Assert.error();
326 return null;
327 }
328 return bound.map(this, pkind);
329 } finally {
330 seen.remove(t);
331 }
332 } else {
333 //cycle
334 return pkind == ProjectionKind.UPWARDS ?
335 syms.objectType : syms.botType;
336 }
337 } else {
338 return t;
339 }
340 }
341
342 private Type mapTypeArgument(Type site, Type declaredBound, Type t, ProjectionKind pkind) {
343 return t.containsAny(vars) ?
344 t.map(new TypeArgumentProjection(site, declaredBound), pkind) :
345 t;
346 }
347
348 class TypeArgumentProjection extends TypeMapping<ProjectionKind> {
349
350 Type site;
351 Type declaredBound;
352
353 TypeArgumentProjection(Type site, Type declaredBound) {
354 this.site = site;
355 this.declaredBound = declaredBound;
356 }
357
358 @Override
359 public Type visitType(Type t, ProjectionKind pkind) {
360 //type argument is some type containing restricted vars
361 if (pkind == ProjectionKind.DOWNWARDS) {
362 //not defined
363 return syms.botType;
364 }
365 Type upper = t.map(TypeProjection.this, ProjectionKind.UPWARDS);
366 Type lower = t.map(TypeProjection.this, ProjectionKind.DOWNWARDS);
367 List<Type> formals = site.tsym.type.getTypeArguments();
368 BoundKind bk;
369 Type bound;
370 if (!isSameType(upper, syms.objectType) &&
371 (declaredBound.containsAny(formals) ||
372 !isSubtype(declaredBound, upper))) {
373 bound = upper;
374 bk = EXTENDS;
375 } else if (!lower.hasTag(BOT)) {
376 bound = lower;
377 bk = SUPER;
378 } else {
379 bound = syms.objectType;
380 bk = UNBOUND;
381 }
382 return makeWildcard(bound, bk);
383 }
384
385 @Override
386 public Type visitWildcardType(WildcardType wt, ProjectionKind pkind) {
387 //type argument is some wildcard whose bound contains restricted vars
388 Type bound = syms.botType;
389 BoundKind bk = wt.kind;
390 switch (wt.kind) {
391 case EXTENDS:
392 bound = wt.type.map(TypeProjection.this, pkind);
393 if (bound.hasTag(BOT)) {
394 return syms.botType;
395 }
396 break;
397 case SUPER:
398 bound = wt.type.map(TypeProjection.this, pkind.complement());
399 if (bound.hasTag(BOT)) {
400 bound = syms.objectType;
401 bk = UNBOUND;
402 }
403 break;
404 }
405 return makeWildcard(bound, bk);
406 }
407
408 private Type makeWildcard(Type bound, BoundKind bk) {
409 return new WildcardType(bound, bk, syms.boundClass) {
410 @Override
411 protected boolean needsStripping() {
412 return true;
413 }
414 };
415 }
416 }
417 }
418
419 /**
420 * Computes an upward projection of given type, and vars. See {@link TypeProjection}.
421 *
422 * @param t the type to be projected
423 * @param vars the set of type variables to be mapped
424 * @return the type obtained as result of the projection
425 */
426 public Type upward(Type t, List<Type> vars) {
427 return t.map(new TypeProjection(vars), ProjectionKind.UPWARDS);
428 }
429
430 /**
431 * Computes the set of captured variables mentioned in a given type. See {@link CaptureScanner}.
432 * This routine is typically used to computed the input set of variables to be used during
433 * an upwards projection (see {@link Types#upward(Type, List)}).
434 *
435 * @param t the type where occurrences of captured variables have to be found
436 * @return the set of captured variables found in t
437 */
438 public List<Type> captures(Type t) {
439 CaptureScanner cs = new CaptureScanner();
440 Set<Type> captures = new HashSet<>();
441 cs.visit(t, captures);
442 return List.from(captures);
443 }
444
445 /**
446 * This visitor scans a type recursively looking for occurrences of captured type variables.
447 */
448 class CaptureScanner extends SimpleVisitor<Void, Set<Type>> {
449
450 @Override
451 public Void visitType(Type t, Set<Type> types) {
452 return null;
453 }
454
455 @Override
456 public Void visitClassType(ClassType t, Set<Type> seen) {
457 if (t.isCompound()) {
458 directSupertypes(t).forEach(s -> visit(s, seen));
459 } else {
460 t.allparams().forEach(ta -> visit(ta, seen));
461 }
462 return null;
463 }
464
465 @Override
466 public Void visitArrayType(ArrayType t, Set<Type> seen) {
467 return visit(t.elemtype, seen);
468 }
469
470 @Override
471 public Void visitWildcardType(WildcardType t, Set<Type> seen) {
472 visit(t.type, seen);
473 return null;
474 }
475
476 @Override
477 public Void visitTypeVar(TypeVar t, Set<Type> seen) {
478 if ((t.tsym.flags() & Flags.SYNTHETIC) != 0 && seen.add(t)) {
479 visit(t.getUpperBound(), seen);
480 }
481 return null;
482 }
483
484 @Override
485 public Void visitCapturedType(CapturedType t, Set<Type> seen) {
486 if (seen.add(t)) {
487 visit(t.getUpperBound(), seen);
488 visit(t.getLowerBound(), seen);
489 }
490 return null;
491 }
492 }
493
494 // </editor-fold>
495
496 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
497 /**
498 * Checks that all the arguments to a class are unbounded
499 * wildcards or something else that doesn't make any restrictions
500 * on the arguments. If a class isUnbounded, a raw super- or
501 * subclass can be cast to it without a warning.
502 * @param t a type
503 * @return true iff the given type is unbounded or raw
504 */
505 public boolean isUnbounded(Type t) {
506 return isUnbounded.visit(t);
507 }
508 // where
509 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
510
511 public Boolean visitType(Type t, Void ignored) {
512 return true;
513 }
514
515 @Override
516 public Boolean visitClassType(ClassType t, Void ignored) {
517 List<Type> parms = t.tsym.type.allparams();
518 List<Type> args = t.allparams();
519 while (parms.nonEmpty()) {
520 WildcardType unb = new WildcardType(syms.objectType,
521 BoundKind.UNBOUND,
522 syms.boundClass,
523 (TypeVar)parms.head);
524 if (!containsType(args.head, unb))
525 return false;
526 parms = parms.tail;
527 args = args.tail;
528 }
529 return true;
530 }
531 };
532 // </editor-fold>
533
534 // <editor-fold defaultstate="collapsed" desc="asSub">
535 /**
536 * Return the least specific subtype of t that starts with symbol
537 * sym. If none exists, return null. The least specific subtype
538 * is determined as follows:
539 *
540 * <p>If there is exactly one parameterized instance of sym that is a
541 * subtype of t, that parameterized instance is returned.<br>
542 * Otherwise, if the plain type or raw type `sym' is a subtype of
543 * type t, the type `sym' itself is returned. Otherwise, null is
544 * returned.
545 */
546 public Type asSub(Type t, Symbol sym) {
547 return asSub.visit(t, sym);
548 }
549 // where
550 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
551
552 public Type visitType(Type t, Symbol sym) {
553 return null;
554 }
555
556 @Override
557 public Type visitClassType(ClassType t, Symbol sym) {
558 if (t.tsym == sym)
559 return t;
560 Type base = asSuper(sym.type, t.tsym);
561 if (base == null)
562 return null;
563 ListBuffer<Type> from = new ListBuffer<>();
564 ListBuffer<Type> to = new ListBuffer<>();
565 try {
566 adapt(base, t, from, to);
567 } catch (AdaptFailure ex) {
568 return null;
569 }
570 Type res = subst(sym.type, from.toList(), to.toList());
571 if (!isSubtype(res, t))
572 return null;
573 ListBuffer<Type> openVars = new ListBuffer<>();
574 for (List<Type> l = sym.type.allparams();
575 l.nonEmpty(); l = l.tail)
576 if (res.contains(l.head) && !t.contains(l.head))
577 openVars.append(l.head);
578 if (openVars.nonEmpty()) {
579 if (t.isRaw()) {
580 // The subtype of a raw type is raw
581 res = erasure(res);
582 } else {
583 // Unbound type arguments default to ?
584 List<Type> opens = openVars.toList();
585 ListBuffer<Type> qs = new ListBuffer<>();
586 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
587 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND,
588 syms.boundClass, (TypeVar) iter.head));
589 }
590 res = subst(res, opens, qs.toList());
591 }
592 }
593 return res;
594 }
595
596 @Override
597 public Type visitErrorType(ErrorType t, Symbol sym) {
598 return t;
599 }
600 };
601 // </editor-fold>
602
603 // <editor-fold defaultstate="collapsed" desc="isConvertible">
604 /**
605 * Is t a subtype of or convertible via boxing/unboxing
606 * conversion to s?
607 */
608 public boolean isConvertible(Type t, Type s, Warner warn) {
609 if (t.hasTag(ERROR)) {
610 return true;
611 }
612 boolean tPrimitive = t.isPrimitive();
613 boolean sPrimitive = s.isPrimitive();
614 if (tPrimitive == sPrimitive) {
615 return isSubtypeUnchecked(t, s, warn);
616 }
617 boolean tUndet = t.hasTag(UNDETVAR);
618 boolean sUndet = s.hasTag(UNDETVAR);
619
620 if (tUndet || sUndet) {
621 return tUndet ?
622 isSubtype(t, boxedTypeOrType(s)) :
623 isSubtype(boxedTypeOrType(t), s);
624 }
625
626 return tPrimitive
627 ? isSubtype(boxedClass(t).type, s)
628 : isSubtype(unboxedType(t), s);
629 }
630
631 /**
632 * Is t a subtype of or convertible via boxing/unboxing
633 * conversions to s?
634 */
635 public boolean isConvertible(Type t, Type s) {
636 return isConvertible(t, s, noWarnings);
637 }
638 // </editor-fold>
639
640 // <editor-fold defaultstate="collapsed" desc="findSam">
641
642 /**
643 * Exception used to report a function descriptor lookup failure. The exception
644 * wraps a diagnostic that can be used to generate more details error
645 * messages.
646 */
647 public static class FunctionDescriptorLookupError extends CompilerInternalException {
648 private static final long serialVersionUID = 0;
649
650 transient JCDiagnostic diagnostic;
651
652 FunctionDescriptorLookupError(boolean dumpStackTraceOnError) {
653 super(dumpStackTraceOnError);
654 this.diagnostic = null;
655 }
656
657 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
658 this.diagnostic = diag;
659 return this;
660 }
661
662 public JCDiagnostic getDiagnostic() {
663 return diagnostic;
664 }
665 }
666
667 /**
668 * A cache that keeps track of function descriptors associated with given
669 * functional interfaces.
670 */
671 class DescriptorCache {
672
673 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<>();
674
675 class FunctionDescriptor {
676 Symbol descSym;
677
678 FunctionDescriptor(Symbol descSym) {
679 this.descSym = descSym;
680 }
681
682 public Symbol getSymbol() {
683 return descSym;
684 }
685
686 public Type getType(Type site) {
687 site = removeWildcards(site);
688 if (site.isIntersection()) {
689 IntersectionClassType ict = (IntersectionClassType)site;
690 for (Type component : ict.getExplicitComponents()) {
691 if (!chk.checkValidGenericType(component)) {
692 //if the inferred functional interface type is not well-formed,
693 //or if it's not a subtype of the original target, issue an error
694 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
695 }
696 }
697 } else {
698 if (!chk.checkValidGenericType(site)) {
699 //if the inferred functional interface type is not well-formed,
700 //or if it's not a subtype of the original target, issue an error
701 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
702 }
703 }
704 return memberType(site, descSym);
705 }
706 }
707
708 class Entry {
709 final FunctionDescriptor cachedDescRes;
710 final int prevMark;
711
712 public Entry(FunctionDescriptor cachedDescRes,
713 int prevMark) {
714 this.cachedDescRes = cachedDescRes;
715 this.prevMark = prevMark;
716 }
717
718 boolean matches(int mark) {
719 return this.prevMark == mark;
720 }
721 }
722
723 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
724 Entry e = _map.get(origin);
725 CompoundScope members = membersClosure(origin.type, false);
726 if (e == null ||
727 !e.matches(members.getMark())) {
728 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
729 _map.put(origin, new Entry(descRes, members.getMark()));
730 return descRes;
731 }
732 else {
733 return e.cachedDescRes;
734 }
735 }
736
737 /**
738 * Compute the function descriptor associated with a given functional interface
739 */
740 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin,
741 CompoundScope membersCache) throws FunctionDescriptorLookupError {
742 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0 || origin.isSealed()) {
743 //t must be an interface
744 throw failure("not.a.functional.intf", origin);
745 }
746
747 final ListBuffer<Symbol> abstracts = new ListBuffer<>();
748 for (Symbol sym : membersCache.getSymbols(new DescriptorFilter(origin))) {
749 Type mtype = memberType(origin.type, sym);
750 if (abstracts.isEmpty()) {
751 abstracts.append(sym);
752 } else if ((sym.name == abstracts.first().name &&
753 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
754 if (!abstracts.stream().filter(msym -> msym.owner.isSubClass(sym.enclClass(), Types.this))
755 .map(msym -> memberType(origin.type, msym))
756 .anyMatch(abstractMType -> isSubSignature(abstractMType, mtype))) {
757 abstracts.append(sym);
758 }
759 } else {
760 //the target method(s) should be the only abstract members of t
761 throw failure("not.a.functional.intf.1", origin,
762 diags.fragment(Fragments.IncompatibleAbstracts(Kinds.kindName(origin), origin)));
763 }
764 }
765 if (abstracts.isEmpty()) {
766 //t must define a suitable non-generic method
767 throw failure("not.a.functional.intf.1", origin,
768 diags.fragment(Fragments.NoAbstracts(Kinds.kindName(origin), origin)));
769 } else if (abstracts.size() == 1) {
770 return new FunctionDescriptor(abstracts.first());
771 } else { // size > 1
772 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
773 if (descRes == null) {
774 //we can get here if the functional interface is ill-formed
775 ListBuffer<JCDiagnostic> descriptors = new ListBuffer<>();
776 for (Symbol desc : abstracts) {
777 String key = desc.type.getThrownTypes().nonEmpty() ?
778 "descriptor.throws" : "descriptor";
779 descriptors.append(diags.fragment(key, desc.name,
780 desc.type.getParameterTypes(),
781 desc.type.getReturnType(),
782 desc.type.getThrownTypes()));
783 }
784 JCDiagnostic msg =
785 diags.fragment(Fragments.IncompatibleDescsInFunctionalIntf(Kinds.kindName(origin),
786 origin));
787 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
788 new JCDiagnostic.MultilineDiagnostic(msg, descriptors.toList());
789 throw failure(incompatibleDescriptors);
790 }
791 return descRes;
792 }
793 }
794
795 /**
796 * Compute a synthetic type for the target descriptor given a list
797 * of override-equivalent methods in the functional interface type.
798 * The resulting method type is a method type that is override-equivalent
799 * and return-type substitutable with each method in the original list.
800 */
801 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
802 return mergeAbstracts(methodSyms, origin.type, false)
803 .map(bestSoFar -> new FunctionDescriptor(bestSoFar.baseSymbol()) {
804 @Override
805 public Type getType(Type origin) {
806 Type mt = memberType(origin, getSymbol());
807 return createMethodTypeWithThrown(mt, bestSoFar.type.getThrownTypes());
808 }
809 }).orElse(null);
810 }
811
812 FunctionDescriptorLookupError failure(String msg, Object... args) {
813 return failure(diags.fragment(msg, args));
814 }
815
816 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
817 return new FunctionDescriptorLookupError(Types.this.dumpStacktraceOnError).setMessage(diag);
818 }
819 }
820
821 private DescriptorCache descCache = new DescriptorCache();
822
823 /**
824 * Find the method descriptor associated to this class symbol - if the
825 * symbol 'origin' is not a functional interface, an exception is thrown.
826 */
827 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
828 return descCache.get(origin).getSymbol();
829 }
830
831 /**
832 * Find the type of the method descriptor associated to this class symbol -
833 * if the symbol 'origin' is not a functional interface, an exception is thrown.
834 */
835 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
836 return descCache.get(origin.tsym).getType(origin);
837 }
838
839 /**
840 * Is given type a functional interface?
841 */
842 public boolean isFunctionalInterface(TypeSymbol tsym) {
843 try {
844 findDescriptorSymbol(tsym);
845 return true;
846 } catch (FunctionDescriptorLookupError ex) {
847 return false;
848 }
849 }
850
851 public boolean isFunctionalInterface(Type site) {
852 try {
853 findDescriptorType(site);
854 return true;
855 } catch (FunctionDescriptorLookupError ex) {
856 return false;
857 }
858 }
859
860 public Type removeWildcards(Type site) {
861 if (site.getTypeArguments().stream().anyMatch(t -> t.hasTag(WILDCARD))) {
862 //compute non-wildcard parameterization - JLS 9.9
863 List<Type> actuals = site.getTypeArguments();
864 List<Type> formals = site.tsym.type.getTypeArguments();
865 ListBuffer<Type> targs = new ListBuffer<>();
866 for (Type formal : formals) {
867 Type actual = actuals.head;
868 Type bound = formal.getUpperBound();
869 if (actuals.head.hasTag(WILDCARD)) {
870 WildcardType wt = (WildcardType)actual;
871 //check that bound does not contain other formals
872 if (bound.containsAny(formals)) {
873 targs.add(wt.type);
874 } else {
875 //compute new type-argument based on declared bound and wildcard bound
876 switch (wt.kind) {
877 case UNBOUND:
878 targs.add(bound);
879 break;
880 case EXTENDS:
881 targs.add(glb(bound, wt.type));
882 break;
883 case SUPER:
884 targs.add(wt.type);
885 break;
886 default:
887 Assert.error("Cannot get here!");
888 }
889 }
890 } else {
891 //not a wildcard - the new type argument remains unchanged
892 targs.add(actual);
893 }
894 actuals = actuals.tail;
895 }
896 return subst(site.tsym.type, formals, targs.toList());
897 } else {
898 return site;
899 }
900 }
901
902 /**
903 * Create a symbol for a class that implements a given functional interface
904 * and overrides its functional descriptor. This routine is used for two
905 * main purposes: (i) checking well-formedness of a functional interface;
906 * (ii) perform functional interface bridge calculation.
907 */
908 public ClassSymbol makeFunctionalInterfaceClass(Env<AttrContext> env, Name name, Type target, long cflags) {
909 if (target == null || target == syms.unknownType) {
910 return null;
911 }
912 Symbol descSym = findDescriptorSymbol(target.tsym);
913 Type descType = findDescriptorType(target);
914 ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass());
915 csym.completer = Completer.NULL_COMPLETER;
916 csym.members_field = WriteableScope.create(csym);
917 MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym);
918 csym.members_field.enter(instDescSym);
919 Type.ClassType ctype = new Type.ClassType(Type.noType, List.nil(), csym);
920 ctype.supertype_field = syms.objectType;
921 ctype.interfaces_field = target.isIntersection() ?
922 directSupertypes(target) :
923 List.of(target);
924 csym.type = ctype;
925 csym.sourcefile = ((ClassSymbol)csym.owner).sourcefile;
926 return csym;
927 }
928
929 /**
930 * Find the minimal set of methods that are overridden by the functional
931 * descriptor in 'origin'. All returned methods are assumed to have different
932 * erased signatures.
933 */
934 public List<Symbol> functionalInterfaceBridges(TypeSymbol origin) {
935 Assert.check(isFunctionalInterface(origin));
936 Symbol descSym = findDescriptorSymbol(origin);
937 CompoundScope members = membersClosure(origin.type, false);
938 ListBuffer<Symbol> overridden = new ListBuffer<>();
939 outer: for (Symbol m2 : members.getSymbolsByName(descSym.name, bridgeFilter)) {
940 if (m2 == descSym) continue;
941 else if (descSym.overrides(m2, origin, Types.this, false)) {
942 for (Symbol m3 : overridden) {
943 if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) ||
944 (m3.overrides(m2, origin, Types.this, false) &&
945 (pendingBridges((ClassSymbol)origin, m3.enclClass()) ||
946 (((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) {
947 continue outer;
948 }
949 }
950 overridden.add(m2);
951 }
952 }
953 return overridden.toList();
954 }
955 //where
956 // Use anonymous class instead of lambda expression intentionally,
957 // because the variable `names` has modifier: final.
958 private Predicate<Symbol> bridgeFilter = new Predicate<Symbol>() {
959 public boolean test(Symbol t) {
960 return t.kind == MTH &&
961 t.name != names.init &&
962 t.name != names.clinit &&
963 (t.flags() & SYNTHETIC) == 0;
964 }
965 };
966
967 private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) {
968 //a symbol will be completed from a classfile if (a) symbol has
969 //an associated file object with CLASS kind and (b) the symbol has
970 //not been entered
971 if (origin.classfile != null &&
972 origin.classfile.getKind() == JavaFileObject.Kind.CLASS &&
973 enter.getEnv(origin) == null) {
974 return false;
975 }
976 if (origin == s) {
977 return true;
978 }
979 for (Type t : interfaces(origin.type)) {
980 if (pendingBridges((ClassSymbol)t.tsym, s)) {
981 return true;
982 }
983 }
984 return false;
985 }
986 // </editor-fold>
987
988 /**
989 * Scope filter used to skip methods that should be ignored (such as methods
990 * overridden by j.l.Object) during function interface conversion interface check
991 */
992 class DescriptorFilter implements Predicate<Symbol> {
993
994 TypeSymbol origin;
995
996 DescriptorFilter(TypeSymbol origin) {
997 this.origin = origin;
998 }
999
1000 @Override
1001 public boolean test(Symbol sym) {
1002 return sym.kind == MTH &&
1003 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
1004 !overridesObjectMethod(origin, sym) &&
1005 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
1006 }
1007 }
1008
1009 // <editor-fold defaultstate="collapsed" desc="isSubtype">
1010 /**
1011 * Is t an unchecked subtype of s?
1012 */
1013 public boolean isSubtypeUnchecked(Type t, Type s) {
1014 return isSubtypeUnchecked(t, s, noWarnings);
1015 }
1016 /**
1017 * Is t an unchecked subtype of s?
1018 */
1019 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
1020 boolean result = isSubtypeUncheckedInternal(t, s, true, warn);
1021 if (result) {
1022 checkUnsafeVarargsConversion(t, s, warn);
1023 }
1024 return result;
1025 }
1026 //where
1027 private boolean isSubtypeUncheckedInternal(Type t, Type s, boolean capture, Warner warn) {
1028 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
1029 if (((ArrayType)t).elemtype.isPrimitive()) {
1030 return isSameType(elemtype(t), elemtype(s));
1031 } else {
1032 return isSubtypeUncheckedInternal(elemtype(t), elemtype(s), false, warn);
1033 }
1034 } else if (isSubtype(t, s, capture)) {
1035 return true;
1036 } else if (t.hasTag(TYPEVAR)) {
1037 return isSubtypeUncheckedInternal(t.getUpperBound(), s, false, warn);
1038 } else if (!s.isRaw()) {
1039 Type t2 = asSuper(t, s.tsym);
1040 if (t2 != null && t2.isRaw()) {
1041 if (isReifiable(s)) {
1042 warn.silentWarn(LintCategory.UNCHECKED);
1043 } else {
1044 warn.warn(LintCategory.UNCHECKED);
1045 }
1046 return true;
1047 }
1048 }
1049 return false;
1050 }
1051
1052 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
1053 if (!t.hasTag(ARRAY) || isReifiable(t)) {
1054 return;
1055 }
1056 ArrayType from = (ArrayType)t;
1057 boolean shouldWarn = false;
1058 switch (s.getTag()) {
1059 case ARRAY:
1060 ArrayType to = (ArrayType)s;
1061 shouldWarn = from.isVarargs() &&
1062 !to.isVarargs() &&
1063 !isReifiable(from);
1064 break;
1065 case CLASS:
1066 shouldWarn = from.isVarargs();
1067 break;
1068 }
1069 if (shouldWarn) {
1070 warn.warn(LintCategory.VARARGS);
1071 }
1072 }
1073
1074 /**
1075 * Is t a subtype of s?<br>
1076 * (not defined for Method and ForAll types)
1077 */
1078 public final boolean isSubtype(Type t, Type s) {
1079 return isSubtype(t, s, true);
1080 }
1081 public final boolean isSubtypeNoCapture(Type t, Type s) {
1082 return isSubtype(t, s, false);
1083 }
1084 public boolean isSubtype(Type t, Type s, boolean capture) {
1085 if (t.equalsIgnoreMetadata(s))
1086 return true;
1087 if (s.isPartial())
1088 return isSuperType(s, t);
1089
1090 if (s.isCompound()) {
1091 for (Type s2 : interfaces(s).prepend(supertype(s))) {
1092 if (!isSubtype(t, s2, capture))
1093 return false;
1094 }
1095 return true;
1096 }
1097
1098 // Generally, if 's' is a lower-bounded type variable, recur on lower bound; but
1099 // for inference variables and intersections, we need to keep 's'
1100 // (see JLS 4.10.2 for intersections and 18.2.3 for inference vars)
1101 if (!t.hasTag(UNDETVAR) && !t.isCompound()) {
1102 // TODO: JDK-8039198, bounds checking sometimes passes in a wildcard as s
1103 Type lower = cvarLowerBound(wildLowerBound(s));
1104 if (s != lower && !lower.hasTag(BOT))
1105 return isSubtype(capture ? capture(t) : t, lower, false);
1106 }
1107
1108 return isSubtype.visit(capture ? capture(t) : t, s);
1109 }
1110 // where
1111 private TypeRelation isSubtype = new TypeRelation()
1112 {
1113 @Override
1114 public Boolean visitType(Type t, Type s) {
1115 switch (t.getTag()) {
1116 case BYTE:
1117 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
1118 case CHAR:
1119 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
1120 case SHORT: case INT: case LONG:
1121 case FLOAT: case DOUBLE:
1122 return t.getTag().isSubRangeOf(s.getTag());
1123 case BOOLEAN: case VOID:
1124 return t.hasTag(s.getTag());
1125 case TYPEVAR:
1126 return isSubtypeNoCapture(t.getUpperBound(), s);
1127 case BOT:
1128 return
1129 s.hasTag(BOT) || s.hasTag(CLASS) ||
1130 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
1131 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
1132 case NONE:
1133 return false;
1134 default:
1135 throw new AssertionError("isSubtype " + t.getTag());
1136 }
1137 }
1138
1139 private Set<TypePair> cache = new HashSet<>();
1140
1141 private boolean containsTypeRecursive(Type t, Type s) {
1142 TypePair pair = new TypePair(t, s);
1143 if (cache.add(pair)) {
1144 try {
1145 return containsType(t.getTypeArguments(),
1146 s.getTypeArguments());
1147 } finally {
1148 cache.remove(pair);
1149 }
1150 } else {
1151 return containsType(t.getTypeArguments(),
1152 rewriteSupers(s).getTypeArguments());
1153 }
1154 }
1155
1156 private Type rewriteSupers(Type t) {
1157 if (!t.isParameterized())
1158 return t;
1159 ListBuffer<Type> from = new ListBuffer<>();
1160 ListBuffer<Type> to = new ListBuffer<>();
1161 adaptSelf(t, from, to);
1162 if (from.isEmpty())
1163 return t;
1164 ListBuffer<Type> rewrite = new ListBuffer<>();
1165 boolean changed = false;
1166 for (Type orig : to.toList()) {
1167 Type s = rewriteSupers(orig);
1168 if (s.isSuperBound() && !s.isExtendsBound()) {
1169 s = new WildcardType(syms.objectType,
1170 BoundKind.UNBOUND,
1171 syms.boundClass,
1172 s.getMetadata());
1173 changed = true;
1174 } else if (s != orig) {
1175 s = new WildcardType(wildUpperBound(s),
1176 BoundKind.EXTENDS,
1177 syms.boundClass,
1178 s.getMetadata());
1179 changed = true;
1180 }
1181 rewrite.append(s);
1182 }
1183 if (changed)
1184 return subst(t.tsym.type, from.toList(), rewrite.toList());
1185 else
1186 return t;
1187 }
1188
1189 @Override
1190 public Boolean visitClassType(ClassType t, Type s) {
1191 Type sup = asSuper(t, s.tsym);
1192 if (sup == null) return false;
1193 // If t is an intersection, sup might not be a class type
1194 if (!sup.hasTag(CLASS)) return isSubtypeNoCapture(sup, s);
1195 return sup.tsym == s.tsym
1196 // Check type variable containment
1197 && (!s.isParameterized() || containsTypeRecursive(s, sup))
1198 && isSubtypeNoCapture(sup.getEnclosingType(),
1199 s.getEnclosingType());
1200 }
1201
1202 @Override
1203 public Boolean visitArrayType(ArrayType t, Type s) {
1204 if (s.hasTag(ARRAY)) {
1205 if (t.elemtype.isPrimitive())
1206 return isSameType(t.elemtype, elemtype(s));
1207 else
1208 return isSubtypeNoCapture(t.elemtype, elemtype(s));
1209 }
1210
1211 if (s.hasTag(CLASS)) {
1212 Name sname = s.tsym.getQualifiedName();
1213 return sname == names.java_lang_Object
1214 || sname == names.java_lang_Cloneable
1215 || sname == names.java_io_Serializable;
1216 }
1217
1218 return false;
1219 }
1220
1221 @Override
1222 public Boolean visitUndetVar(UndetVar t, Type s) {
1223 //todo: test against origin needed? or replace with substitution?
1224 if (t == s || t.qtype == s || s.hasTag(ERROR)) {
1225 return true;
1226 } else if (s.hasTag(BOT)) {
1227 //if 's' is 'null' there's no instantiated type U for which
1228 //U <: s (but 'null' itself, which is not a valid type)
1229 return false;
1230 }
1231
1232 t.addBound(InferenceBound.UPPER, s, Types.this);
1233 return true;
1234 }
1235
1236 @Override
1237 public Boolean visitErrorType(ErrorType t, Type s) {
1238 return true;
1239 }
1240 };
1241
1242 /**
1243 * Is t a subtype of every type in given list `ts'?<br>
1244 * (not defined for Method and ForAll types)<br>
1245 * Allows unchecked conversions.
1246 */
1247 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
1248 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
1249 if (!isSubtypeUnchecked(t, l.head, warn))
1250 return false;
1251 return true;
1252 }
1253
1254 /**
1255 * Are corresponding elements of ts subtypes of ss? If lists are
1256 * of different length, return false.
1257 */
1258 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
1259 while (ts.tail != null && ss.tail != null
1260 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1261 isSubtype(ts.head, ss.head)) {
1262 ts = ts.tail;
1263 ss = ss.tail;
1264 }
1265 return ts.tail == null && ss.tail == null;
1266 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1267 }
1268
1269 /**
1270 * Are corresponding elements of ts subtypes of ss, allowing
1271 * unchecked conversions? If lists are of different length,
1272 * return false.
1273 **/
1274 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
1275 while (ts.tail != null && ss.tail != null
1276 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1277 isSubtypeUnchecked(ts.head, ss.head, warn)) {
1278 ts = ts.tail;
1279 ss = ss.tail;
1280 }
1281 return ts.tail == null && ss.tail == null;
1282 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1283 }
1284 // </editor-fold>
1285
1286 // <editor-fold defaultstate="collapsed" desc="isSuperType">
1287 /**
1288 * Is t a supertype of s?
1289 */
1290 public boolean isSuperType(Type t, Type s) {
1291 switch (t.getTag()) {
1292 case ERROR:
1293 return true;
1294 case UNDETVAR: {
1295 UndetVar undet = (UndetVar)t;
1296 if (t == s ||
1297 undet.qtype == s ||
1298 s.hasTag(ERROR) ||
1299 s.hasTag(BOT)) {
1300 return true;
1301 }
1302 undet.addBound(InferenceBound.LOWER, s, this);
1303 return true;
1304 }
1305 default:
1306 return isSubtype(s, t);
1307 }
1308 }
1309 // </editor-fold>
1310
1311 // <editor-fold defaultstate="collapsed" desc="isSameType">
1312 /**
1313 * Are corresponding elements of the lists the same type? If
1314 * lists are of different length, return false.
1315 */
1316 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
1317 while (ts.tail != null && ss.tail != null
1318 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1319 isSameType(ts.head, ss.head)) {
1320 ts = ts.tail;
1321 ss = ss.tail;
1322 }
1323 return ts.tail == null && ss.tail == null;
1324 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1325 }
1326
1327 /**
1328 * A polymorphic signature method (JLS 15.12.3) is a method that
1329 * (i) is declared in the java.lang.invoke.MethodHandle/VarHandle classes;
1330 * (ii) takes a single variable arity parameter;
1331 * (iii) whose declared type is Object[];
1332 * (iv) has any return type, Object signifying a polymorphic return type; and
1333 * (v) is native.
1334 */
1335 public boolean isSignaturePolymorphic(MethodSymbol msym) {
1336 List<Type> argtypes = msym.type.getParameterTypes();
1337 return (msym.flags_field & NATIVE) != 0 &&
1338 (msym.owner == syms.methodHandleType.tsym || msym.owner == syms.varHandleType.tsym) &&
1339 argtypes.length() == 1 &&
1340 argtypes.head.hasTag(TypeTag.ARRAY) &&
1341 ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym;
1342 }
1343
1344 /**
1345 * Is t the same type as s?
1346 */
1347 public boolean isSameType(Type t, Type s) {
1348 return isSameTypeVisitor.visit(t, s);
1349 }
1350 // where
1351
1352 /**
1353 * Type-equality relation - type variables are considered
1354 * equals if they share the same object identity.
1355 */
1356 TypeRelation isSameTypeVisitor = new TypeRelation() {
1357
1358 public Boolean visitType(Type t, Type s) {
1359 if (t.equalsIgnoreMetadata(s))
1360 return true;
1361
1362 if (s.isPartial())
1363 return visit(s, t);
1364
1365 switch (t.getTag()) {
1366 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1367 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
1368 return t.hasTag(s.getTag());
1369 case TYPEVAR: {
1370 if (s.hasTag(TYPEVAR)) {
1371 //type-substitution does not preserve type-var types
1372 //check that type var symbols and bounds are indeed the same
1373 return t == s;
1374 }
1375 else {
1376 //special case for s == ? super X, where upper(s) = u
1377 //check that u == t, where u has been set by Type.withTypeVar
1378 return s.isSuperBound() &&
1379 !s.isExtendsBound() &&
1380 visit(t, wildUpperBound(s));
1381 }
1382 }
1383 default:
1384 throw new AssertionError("isSameType " + t.getTag());
1385 }
1386 }
1387
1388 @Override
1389 public Boolean visitWildcardType(WildcardType t, Type s) {
1390 if (!s.hasTag(WILDCARD)) {
1391 return false;
1392 } else {
1393 WildcardType t2 = (WildcardType)s;
1394 return (t.kind == t2.kind || (t.isExtendsBound() && s.isExtendsBound())) &&
1395 isSameType(t.type, t2.type);
1396 }
1397 }
1398
1399 @Override
1400 public Boolean visitClassType(ClassType t, Type s) {
1401 if (t == s)
1402 return true;
1403
1404 if (s.isPartial())
1405 return visit(s, t);
1406
1407 if (s.isSuperBound() && !s.isExtendsBound())
1408 return visit(t, wildUpperBound(s)) && visit(t, wildLowerBound(s));
1409
1410 if (t.isCompound() && s.isCompound()) {
1411 if (!visit(supertype(t), supertype(s)))
1412 return false;
1413
1414 Map<Symbol,Type> tMap = new HashMap<>();
1415 for (Type ti : interfaces(t)) {
1416 tMap.put(ti.tsym, ti);
1417 }
1418 for (Type si : interfaces(s)) {
1419 if (!tMap.containsKey(si.tsym))
1420 return false;
1421 Type ti = tMap.remove(si.tsym);
1422 if (!visit(ti, si))
1423 return false;
1424 }
1425 return tMap.isEmpty();
1426 }
1427 return t.tsym == s.tsym
1428 && visit(t.getEnclosingType(), s.getEnclosingType())
1429 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
1430 }
1431
1432 @Override
1433 public Boolean visitArrayType(ArrayType t, Type s) {
1434 if (t == s)
1435 return true;
1436
1437 if (s.isPartial())
1438 return visit(s, t);
1439
1440 return s.hasTag(ARRAY)
1441 && containsTypeEquivalent(t.elemtype, elemtype(s));
1442 }
1443
1444 @Override
1445 public Boolean visitMethodType(MethodType t, Type s) {
1446 // isSameType for methods does not take thrown
1447 // exceptions into account!
1448 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
1449 }
1450
1451 @Override
1452 public Boolean visitPackageType(PackageType t, Type s) {
1453 return t == s;
1454 }
1455
1456 @Override
1457 public Boolean visitForAll(ForAll t, Type s) {
1458 if (!s.hasTag(FORALL)) {
1459 return false;
1460 }
1461
1462 ForAll forAll = (ForAll)s;
1463 return hasSameBounds(t, forAll)
1464 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1465 }
1466
1467 @Override
1468 public Boolean visitUndetVar(UndetVar t, Type s) {
1469 if (s.hasTag(WILDCARD)) {
1470 // FIXME, this might be leftovers from before capture conversion
1471 return false;
1472 }
1473
1474 if (t == s || t.qtype == s || s.hasTag(ERROR)) {
1475 return true;
1476 }
1477
1478 t.addBound(InferenceBound.EQ, s, Types.this);
1479
1480 return true;
1481 }
1482
1483 @Override
1484 public Boolean visitErrorType(ErrorType t, Type s) {
1485 return true;
1486 }
1487 };
1488
1489 // </editor-fold>
1490
1491 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1492 public boolean containedBy(Type t, Type s) {
1493 switch (t.getTag()) {
1494 case UNDETVAR:
1495 if (s.hasTag(WILDCARD)) {
1496 UndetVar undetvar = (UndetVar)t;
1497 WildcardType wt = (WildcardType)s;
1498 switch(wt.kind) {
1499 case UNBOUND:
1500 break;
1501 case EXTENDS: {
1502 Type bound = wildUpperBound(s);
1503 undetvar.addBound(InferenceBound.UPPER, bound, this);
1504 break;
1505 }
1506 case SUPER: {
1507 Type bound = wildLowerBound(s);
1508 undetvar.addBound(InferenceBound.LOWER, bound, this);
1509 break;
1510 }
1511 }
1512 return true;
1513 } else {
1514 return isSameType(t, s);
1515 }
1516 case ERROR:
1517 return true;
1518 default:
1519 return containsType(s, t);
1520 }
1521 }
1522
1523 boolean containsType(List<Type> ts, List<Type> ss) {
1524 while (ts.nonEmpty() && ss.nonEmpty()
1525 && containsType(ts.head, ss.head)) {
1526 ts = ts.tail;
1527 ss = ss.tail;
1528 }
1529 return ts.isEmpty() && ss.isEmpty();
1530 }
1531
1532 /**
1533 * Check if t contains s.
1534 *
1535 * <p>T contains S if:
1536 *
1537 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1538 *
1539 * <p>This relation is only used by ClassType.isSubtype(), that
1540 * is,
1541 *
1542 * <p>{@code C<S> <: C<T> if T contains S.}
1543 *
1544 * <p>Because of F-bounds, this relation can lead to infinite
1545 * recursion. Thus we must somehow break that recursion. Notice
1546 * that containsType() is only called from ClassType.isSubtype().
1547 * Since the arguments have already been checked against their
1548 * bounds, we know:
1549 *
1550 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1551 *
1552 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1553 *
1554 * @param t a type
1555 * @param s a type
1556 */
1557 public boolean containsType(Type t, Type s) {
1558 return containsType.visit(t, s);
1559 }
1560 // where
1561 private TypeRelation containsType = new TypeRelation() {
1562
1563 public Boolean visitType(Type t, Type s) {
1564 if (s.isPartial())
1565 return containedBy(s, t);
1566 else
1567 return isSameType(t, s);
1568 }
1569
1570 // void debugContainsType(WildcardType t, Type s) {
1571 // System.err.println();
1572 // System.err.format(" does %s contain %s?%n", t, s);
1573 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1574 // wildUpperBound(s), s, t, wildUpperBound(t),
1575 // t.isSuperBound()
1576 // || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t)));
1577 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1578 // wildLowerBound(t), t, s, wildLowerBound(s),
1579 // t.isExtendsBound()
1580 // || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s)));
1581 // System.err.println();
1582 // }
1583
1584 @Override
1585 public Boolean visitWildcardType(WildcardType t, Type s) {
1586 if (s.isPartial())
1587 return containedBy(s, t);
1588 else {
1589 // debugContainsType(t, s);
1590 return isSameWildcard(t, s)
1591 || isCaptureOf(s, t)
1592 || ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))) &&
1593 (t.isSuperBound() || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t))));
1594 }
1595 }
1596
1597 @Override
1598 public Boolean visitUndetVar(UndetVar t, Type s) {
1599 if (!s.hasTag(WILDCARD)) {
1600 return isSameType(t, s);
1601 } else {
1602 return false;
1603 }
1604 }
1605
1606 @Override
1607 public Boolean visitErrorType(ErrorType t, Type s) {
1608 return true;
1609 }
1610 };
1611
1612 public boolean isCaptureOf(Type s, WildcardType t) {
1613 if (!s.hasTag(TYPEVAR) || !((TypeVar)s).isCaptured())
1614 return false;
1615 return isSameWildcard(t, ((CapturedType)s).wildcard);
1616 }
1617
1618 public boolean isSameWildcard(WildcardType t, Type s) {
1619 if (!s.hasTag(WILDCARD))
1620 return false;
1621 WildcardType w = (WildcardType)s;
1622 return w.kind == t.kind && w.type == t.type;
1623 }
1624
1625 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1626 while (ts.nonEmpty() && ss.nonEmpty()
1627 && containsTypeEquivalent(ts.head, ss.head)) {
1628 ts = ts.tail;
1629 ss = ss.tail;
1630 }
1631 return ts.isEmpty() && ss.isEmpty();
1632 }
1633 // </editor-fold>
1634
1635 // <editor-fold defaultstate="collapsed" desc="isCastable">
1636 public boolean isCastable(Type t, Type s) {
1637 return isCastable(t, s, noWarnings);
1638 }
1639
1640 /**
1641 * Is t castable to s?<br>
1642 * s is assumed to be an erased type.<br>
1643 * (not defined for Method and ForAll types).
1644 */
1645 public boolean isCastable(Type t, Type s, Warner warn) {
1646 // if same type
1647 if (t == s)
1648 return true;
1649 // if one of the types is primitive
1650 if (t.isPrimitive() != s.isPrimitive()) {
1651 t = skipTypeVars(t, false);
1652 return (isConvertible(t, s, warn)
1653 || (s.isPrimitive() &&
1654 isSubtype(boxedClass(s).type, t)));
1655 }
1656 boolean result;
1657 if (warn != warnStack.head) {
1658 try {
1659 warnStack = warnStack.prepend(warn);
1660 checkUnsafeVarargsConversion(t, s, warn);
1661 result = isCastable.visit(t,s);
1662 } finally {
1663 warnStack = warnStack.tail;
1664 }
1665 } else {
1666 result = isCastable.visit(t,s);
1667 }
1668 if (result && t.hasTag(CLASS) && t.tsym.kind.matches(Kinds.KindSelector.TYP)
1669 && s.hasTag(CLASS) && s.tsym.kind.matches(Kinds.KindSelector.TYP)
1670 && (t.tsym.isSealed() || s.tsym.isSealed())) {
1671 return (t.isCompound() || s.isCompound()) ?
1672 true :
1673 !(new DisjointChecker().areDisjoint((ClassSymbol)t.tsym, (ClassSymbol)s.tsym));
1674 }
1675 return result;
1676 }
1677 // where
1678 class DisjointChecker {
1679 Set<Pair<ClassSymbol, ClassSymbol>> pairsSeen = new HashSet<>();
1680 private boolean areDisjoint(ClassSymbol ts, ClassSymbol ss) {
1681 Pair<ClassSymbol, ClassSymbol> newPair = new Pair<>(ts, ss);
1682 /* if we are seeing the same pair again then there is an issue with the sealed hierarchy
1683 * bail out, a detailed error will be reported downstream
1684 */
1685 if (!pairsSeen.add(newPair))
1686 return false;
1687 if (isSubtype(erasure(ts.type), erasure(ss.type))) {
1688 return false;
1689 }
1690 // if both are classes or both are interfaces, shortcut
1691 if (ts.isInterface() == ss.isInterface() && isSubtype(erasure(ss.type), erasure(ts.type))) {
1692 return false;
1693 }
1694 if (ts.isInterface() && !ss.isInterface()) {
1695 /* so ts is interface but ss is a class
1696 * an interface is disjoint from a class if the class is disjoint form the interface
1697 */
1698 return areDisjoint(ss, ts);
1699 }
1700 // a final class that is not subtype of ss is disjoint
1701 if (!ts.isInterface() && ts.isFinal()) {
1702 return true;
1703 }
1704 // if at least one is sealed
1705 if (ts.isSealed() || ss.isSealed()) {
1706 // permitted subtypes have to be disjoint with the other symbol
1707 ClassSymbol sealedOne = ts.isSealed() ? ts : ss;
1708 ClassSymbol other = sealedOne == ts ? ss : ts;
1709 return sealedOne.getPermittedSubclasses().stream().allMatch(type -> areDisjoint((ClassSymbol)type.tsym, other));
1710 }
1711 return false;
1712 }
1713 }
1714
1715 private TypeRelation isCastable = new TypeRelation() {
1716
1717 public Boolean visitType(Type t, Type s) {
1718 if (s.hasTag(ERROR) || t.hasTag(NONE))
1719 return true;
1720
1721 switch (t.getTag()) {
1722 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1723 case DOUBLE:
1724 return s.isNumeric();
1725 case BOOLEAN:
1726 return s.hasTag(BOOLEAN);
1727 case VOID:
1728 return false;
1729 case BOT:
1730 return isSubtype(t, s);
1731 default:
1732 throw new AssertionError();
1733 }
1734 }
1735
1736 @Override
1737 public Boolean visitWildcardType(WildcardType t, Type s) {
1738 return isCastable(wildUpperBound(t), s, warnStack.head);
1739 }
1740
1741 @Override
1742 public Boolean visitClassType(ClassType t, Type s) {
1743 if (s.hasTag(ERROR) || s.hasTag(BOT))
1744 return true;
1745
1746 if (s.hasTag(TYPEVAR)) {
1747 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1748 warnStack.head.warn(LintCategory.UNCHECKED);
1749 return true;
1750 } else {
1751 return false;
1752 }
1753 }
1754
1755 if (t.isCompound() || s.isCompound()) {
1756 return !t.isCompound() ?
1757 visitCompoundType((ClassType)s, t, true) :
1758 visitCompoundType(t, s, false);
1759 }
1760
1761 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) {
1762 boolean upcast;
1763 if ((upcast = isSubtype(erasure(t), erasure(s)))
1764 || isSubtype(erasure(s), erasure(t))) {
1765 if (!upcast && s.hasTag(ARRAY)) {
1766 if (!isReifiable(s))
1767 warnStack.head.warn(LintCategory.UNCHECKED);
1768 return true;
1769 } else if (s.isRaw()) {
1770 return true;
1771 } else if (t.isRaw()) {
1772 if (!isUnbounded(s))
1773 warnStack.head.warn(LintCategory.UNCHECKED);
1774 return true;
1775 }
1776 // Assume |a| <: |b|
1777 final Type a = upcast ? t : s;
1778 final Type b = upcast ? s : t;
1779 final boolean HIGH = true;
1780 final boolean LOW = false;
1781 final boolean DONT_REWRITE_TYPEVARS = false;
1782 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1783 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1784 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1785 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1786 Type lowSub = asSub(bLow, aLow.tsym);
1787 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1788 if (highSub == null) {
1789 final boolean REWRITE_TYPEVARS = true;
1790 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1791 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1792 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1793 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1794 lowSub = asSub(bLow, aLow.tsym);
1795 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1796 }
1797 if (highSub != null) {
1798 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1799 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1800 }
1801 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1802 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1803 && !disjointTypes(aLow.allparams(), highSub.allparams())
1804 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1805 if (upcast ? giveWarning(a, b) :
1806 giveWarning(b, a))
1807 warnStack.head.warn(LintCategory.UNCHECKED);
1808 return true;
1809 }
1810 }
1811 if (isReifiable(s))
1812 return isSubtypeUnchecked(a, b);
1813 else
1814 return isSubtypeUnchecked(a, b, warnStack.head);
1815 }
1816
1817 // Sidecast
1818 if (s.hasTag(CLASS)) {
1819 if ((s.tsym.flags() & INTERFACE) != 0) {
1820 return ((t.tsym.flags() & FINAL) == 0)
1821 ? sideCast(t, s, warnStack.head)
1822 : sideCastFinal(t, s, warnStack.head);
1823 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1824 return ((s.tsym.flags() & FINAL) == 0)
1825 ? sideCast(t, s, warnStack.head)
1826 : sideCastFinal(t, s, warnStack.head);
1827 } else {
1828 // unrelated class types
1829 return false;
1830 }
1831 }
1832 }
1833 return false;
1834 }
1835
1836 boolean visitCompoundType(ClassType ct, Type s, boolean reverse) {
1837 Warner warn = noWarnings;
1838 for (Type c : directSupertypes(ct)) {
1839 warn.clear();
1840 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1841 return false;
1842 }
1843 if (warn.hasLint(LintCategory.UNCHECKED))
1844 warnStack.head.warn(LintCategory.UNCHECKED);
1845 return true;
1846 }
1847
1848 @Override
1849 public Boolean visitArrayType(ArrayType t, Type s) {
1850 switch (s.getTag()) {
1851 case ERROR:
1852 case BOT:
1853 return true;
1854 case TYPEVAR:
1855 if (isCastable(s, t, noWarnings)) {
1856 warnStack.head.warn(LintCategory.UNCHECKED);
1857 return true;
1858 } else {
1859 return false;
1860 }
1861 case CLASS:
1862 return isSubtype(t, s);
1863 case ARRAY:
1864 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1865 return elemtype(t).hasTag(elemtype(s).getTag());
1866 } else {
1867 return isCastable(elemtype(t), elemtype(s), warnStack.head);
1868 }
1869 default:
1870 return false;
1871 }
1872 }
1873
1874 @Override
1875 public Boolean visitTypeVar(TypeVar t, Type s) {
1876 switch (s.getTag()) {
1877 case ERROR:
1878 case BOT:
1879 return true;
1880 case TYPEVAR:
1881 if (isSubtype(t, s)) {
1882 return true;
1883 } else if (isCastable(t.getUpperBound(), s, noWarnings)) {
1884 warnStack.head.warn(LintCategory.UNCHECKED);
1885 return true;
1886 } else {
1887 return false;
1888 }
1889 default:
1890 return isCastable(t.getUpperBound(), s, warnStack.head);
1891 }
1892 }
1893
1894 @Override
1895 public Boolean visitErrorType(ErrorType t, Type s) {
1896 return true;
1897 }
1898 };
1899 // </editor-fold>
1900
1901 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1902 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1903 while (ts.tail != null && ss.tail != null) {
1904 if (disjointType(ts.head, ss.head)) return true;
1905 ts = ts.tail;
1906 ss = ss.tail;
1907 }
1908 return false;
1909 }
1910
1911 /**
1912 * Two types or wildcards are considered disjoint if it can be
1913 * proven that no type can be contained in both. It is
1914 * conservative in that it is allowed to say that two types are
1915 * not disjoint, even though they actually are.
1916 *
1917 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1918 * {@code X} and {@code Y} are not disjoint.
1919 */
1920 public boolean disjointType(Type t, Type s) {
1921 return disjointType.visit(t, s);
1922 }
1923 // where
1924 private TypeRelation disjointType = new TypeRelation() {
1925
1926 private Set<TypePair> cache = new HashSet<>();
1927
1928 @Override
1929 public Boolean visitType(Type t, Type s) {
1930 if (s.hasTag(WILDCARD))
1931 return visit(s, t);
1932 else
1933 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1934 }
1935
1936 private boolean isCastableRecursive(Type t, Type s) {
1937 TypePair pair = new TypePair(t, s);
1938 if (cache.add(pair)) {
1939 try {
1940 return Types.this.isCastable(t, s);
1941 } finally {
1942 cache.remove(pair);
1943 }
1944 } else {
1945 return true;
1946 }
1947 }
1948
1949 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1950 TypePair pair = new TypePair(t, s);
1951 if (cache.add(pair)) {
1952 try {
1953 return Types.this.notSoftSubtype(t, s);
1954 } finally {
1955 cache.remove(pair);
1956 }
1957 } else {
1958 return false;
1959 }
1960 }
1961
1962 @Override
1963 public Boolean visitWildcardType(WildcardType t, Type s) {
1964 if (t.isUnbound())
1965 return false;
1966
1967 if (!s.hasTag(WILDCARD)) {
1968 if (t.isExtendsBound())
1969 return notSoftSubtypeRecursive(s, t.type);
1970 else
1971 return notSoftSubtypeRecursive(t.type, s);
1972 }
1973
1974 if (s.isUnbound())
1975 return false;
1976
1977 if (t.isExtendsBound()) {
1978 if (s.isExtendsBound())
1979 return !isCastableRecursive(t.type, wildUpperBound(s));
1980 else if (s.isSuperBound())
1981 return notSoftSubtypeRecursive(wildLowerBound(s), t.type);
1982 } else if (t.isSuperBound()) {
1983 if (s.isExtendsBound())
1984 return notSoftSubtypeRecursive(t.type, wildUpperBound(s));
1985 }
1986 return false;
1987 }
1988 };
1989 // </editor-fold>
1990
1991 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds">
1992 public List<Type> cvarLowerBounds(List<Type> ts) {
1993 return ts.map(cvarLowerBoundMapping);
1994 }
1995 private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() {
1996 @Override
1997 public Type visitCapturedType(CapturedType t, Void _unused) {
1998 return cvarLowerBound(t);
1999 }
2000 };
2001 // </editor-fold>
2002
2003 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
2004 /**
2005 * This relation answers the question: is impossible that
2006 * something of type `t' can be a subtype of `s'? This is
2007 * different from the question "is `t' not a subtype of `s'?"
2008 * when type variables are involved: Integer is not a subtype of T
2009 * where {@code <T extends Number>} but it is not true that Integer cannot
2010 * possibly be a subtype of T.
2011 */
2012 public boolean notSoftSubtype(Type t, Type s) {
2013 if (t == s) return false;
2014 if (t.hasTag(TYPEVAR)) {
2015 TypeVar tv = (TypeVar) t;
2016 return !isCastable(tv.getUpperBound(),
2017 relaxBound(s),
2018 noWarnings);
2019 }
2020 if (!s.hasTag(WILDCARD))
2021 s = cvarUpperBound(s);
2022
2023 return !isSubtype(t, relaxBound(s));
2024 }
2025
2026 private Type relaxBound(Type t) {
2027 return (t.hasTag(TYPEVAR)) ?
2028 rewriteQuantifiers(skipTypeVars(t, false), true, true) :
2029 t;
2030 }
2031 // </editor-fold>
2032
2033 // <editor-fold defaultstate="collapsed" desc="isReifiable">
2034 public boolean isReifiable(Type t) {
2035 return isReifiable.visit(t);
2036 }
2037 // where
2038 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
2039
2040 public Boolean visitType(Type t, Void ignored) {
2041 return true;
2042 }
2043
2044 @Override
2045 public Boolean visitClassType(ClassType t, Void ignored) {
2046 if (t.isCompound())
2047 return false;
2048 else {
2049 if (!t.isParameterized())
2050 return true;
2051
2052 for (Type param : t.allparams()) {
2053 if (!param.isUnbound())
2054 return false;
2055 }
2056 return true;
2057 }
2058 }
2059
2060 @Override
2061 public Boolean visitArrayType(ArrayType t, Void ignored) {
2062 return visit(t.elemtype);
2063 }
2064
2065 @Override
2066 public Boolean visitTypeVar(TypeVar t, Void ignored) {
2067 return false;
2068 }
2069 };
2070 // </editor-fold>
2071
2072 // <editor-fold defaultstate="collapsed" desc="Array Utils">
2073 public boolean isArray(Type t) {
2074 while (t.hasTag(WILDCARD))
2075 t = wildUpperBound(t);
2076 return t.hasTag(ARRAY);
2077 }
2078
2079 /**
2080 * The element type of an array.
2081 */
2082 public Type elemtype(Type t) {
2083 switch (t.getTag()) {
2084 case WILDCARD:
2085 return elemtype(wildUpperBound(t));
2086 case ARRAY:
2087 return ((ArrayType)t).elemtype;
2088 case FORALL:
2089 return elemtype(((ForAll)t).qtype);
2090 case ERROR:
2091 return t;
2092 default:
2093 return null;
2094 }
2095 }
2096
2097 public Type elemtypeOrType(Type t) {
2098 Type elemtype = elemtype(t);
2099 return elemtype != null ?
2100 elemtype :
2101 t;
2102 }
2103
2104 /**
2105 * Mapping to take element type of an arraytype
2106 */
2107 private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() {
2108 @Override
2109 public Type visitArrayType(ArrayType t, Void _unused) {
2110 return t.elemtype;
2111 }
2112
2113 @Override
2114 public Type visitTypeVar(TypeVar t, Void _unused) {
2115 return visit(skipTypeVars(t, false));
2116 }
2117 };
2118
2119 /**
2120 * The number of dimensions of an array type.
2121 */
2122 public int dimensions(Type t) {
2123 int result = 0;
2124 while (t.hasTag(ARRAY)) {
2125 result++;
2126 t = elemtype(t);
2127 }
2128 return result;
2129 }
2130
2131 /**
2132 * Returns an ArrayType with the component type t
2133 *
2134 * @param t The component type of the ArrayType
2135 * @return the ArrayType for the given component
2136 */
2137 public ArrayType makeArrayType(Type t) {
2138 return makeArrayType(t, 1);
2139 }
2140
2141 public ArrayType makeArrayType(Type t, int dimensions) {
2142 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) {
2143 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
2144 }
2145 ArrayType result = new ArrayType(t, syms.arrayClass);
2146 for (int i = 1; i < dimensions; i++) {
2147 result = new ArrayType(result, syms.arrayClass);
2148 }
2149 return result;
2150 }
2151 // </editor-fold>
2152
2153 // <editor-fold defaultstate="collapsed" desc="asSuper">
2154 /**
2155 * Return the (most specific) base type of t that starts with the
2156 * given symbol. If none exists, return null.
2157 *
2158 * Caveat Emptor: Since javac represents the class of all arrays with a singleton
2159 * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant,
2160 * this method could yield surprising answers when invoked on arrays. For example when
2161 * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null.
2162 *
2163 * @param t a type
2164 * @param sym a symbol
2165 */
2166 public Type asSuper(Type t, Symbol sym) {
2167 /* Some examples:
2168 *
2169 * (Enum<E>, Comparable) => Comparable<E>
2170 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind>
2171 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree
2172 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) =>
2173 * Iterable<capture#160 of ? extends c.s.s.d.DocTree>
2174 */
2175 if (sym.type == syms.objectType) { //optimization
2176 return syms.objectType;
2177 }
2178 return asSuper.visit(t, sym);
2179 }
2180 // where
2181 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
2182
2183 private Set<Symbol> seenTypes = new HashSet<>();
2184
2185 public Type visitType(Type t, Symbol sym) {
2186 return null;
2187 }
2188
2189 @Override
2190 public Type visitClassType(ClassType t, Symbol sym) {
2191 if (t.tsym == sym)
2192 return t;
2193
2194 Symbol c = t.tsym;
2195 if (!seenTypes.add(c)) {
2196 return null;
2197 }
2198 try {
2199 Type st = supertype(t);
2200 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) {
2201 Type x = asSuper(st, sym);
2202 if (x != null)
2203 return x;
2204 }
2205 if ((sym.flags() & INTERFACE) != 0) {
2206 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
2207 if (!l.head.hasTag(ERROR)) {
2208 Type x = asSuper(l.head, sym);
2209 if (x != null)
2210 return x;
2211 }
2212 }
2213 }
2214 return null;
2215 } finally {
2216 seenTypes.remove(c);
2217 }
2218 }
2219
2220 @Override
2221 public Type visitArrayType(ArrayType t, Symbol sym) {
2222 return isSubtype(t, sym.type) ? sym.type : null;
2223 }
2224
2225 @Override
2226 public Type visitTypeVar(TypeVar t, Symbol sym) {
2227 if (t.tsym == sym)
2228 return t;
2229 else
2230 return asSuper(t.getUpperBound(), sym);
2231 }
2232
2233 @Override
2234 public Type visitErrorType(ErrorType t, Symbol sym) {
2235 return t;
2236 }
2237 };
2238
2239 /**
2240 * Return the base type of t or any of its outer types that starts
2241 * with the given symbol. If none exists, return null.
2242 *
2243 * @param t a type
2244 * @param sym a symbol
2245 */
2246 public Type asOuterSuper(Type t, Symbol sym) {
2247 switch (t.getTag()) {
2248 case CLASS:
2249 do {
2250 Type s = asSuper(t, sym);
2251 if (s != null) return s;
2252 t = t.getEnclosingType();
2253 } while (t.hasTag(CLASS));
2254 return null;
2255 case ARRAY:
2256 return isSubtype(t, sym.type) ? sym.type : null;
2257 case TYPEVAR:
2258 return asSuper(t, sym);
2259 case ERROR:
2260 return t;
2261 default:
2262 return null;
2263 }
2264 }
2265
2266 /**
2267 * Return the base type of t or any of its enclosing types that
2268 * starts with the given symbol. If none exists, return null.
2269 *
2270 * @param t a type
2271 * @param sym a symbol
2272 */
2273 public Type asEnclosingSuper(Type t, Symbol sym) {
2274 switch (t.getTag()) {
2275 case CLASS:
2276 do {
2277 Type s = asSuper(t, sym);
2278 if (s != null) return s;
2279 Type outer = t.getEnclosingType();
2280 t = (outer.hasTag(CLASS)) ? outer :
2281 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
2282 Type.noType;
2283 } while (t.hasTag(CLASS));
2284 return null;
2285 case ARRAY:
2286 return isSubtype(t, sym.type) ? sym.type : null;
2287 case TYPEVAR:
2288 return asSuper(t, sym);
2289 case ERROR:
2290 return t;
2291 default:
2292 return null;
2293 }
2294 }
2295 // </editor-fold>
2296
2297 // <editor-fold defaultstate="collapsed" desc="memberType">
2298 /**
2299 * The type of given symbol, seen as a member of t.
2300 *
2301 * @param t a type
2302 * @param sym a symbol
2303 */
2304 public Type memberType(Type t, Symbol sym) {
2305 return (sym.flags() & STATIC) != 0
2306 ? sym.type
2307 : memberType.visit(t, sym);
2308 }
2309 // where
2310 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
2311
2312 public Type visitType(Type t, Symbol sym) {
2313 return sym.type;
2314 }
2315
2316 @Override
2317 public Type visitWildcardType(WildcardType t, Symbol sym) {
2318 return memberType(wildUpperBound(t), sym);
2319 }
2320
2321 @Override
2322 public Type visitClassType(ClassType t, Symbol sym) {
2323 Symbol owner = sym.owner;
2324 long flags = sym.flags();
2325 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
2326 Type base = asOuterSuper(t, owner);
2327 //if t is an intersection type T = CT & I1 & I2 ... & In
2328 //its supertypes CT, I1, ... In might contain wildcards
2329 //so we need to go through capture conversion
2330 base = t.isCompound() ? capture(base) : base;
2331 if (base != null) {
2332 List<Type> ownerParams = owner.type.allparams();
2333 List<Type> baseParams = base.allparams();
2334 if (ownerParams.nonEmpty()) {
2335 if (baseParams.isEmpty()) {
2336 // then base is a raw type
2337 return erasure(sym.type);
2338 } else {
2339 return subst(sym.type, ownerParams, baseParams);
2340 }
2341 }
2342 }
2343 }
2344 return sym.type;
2345 }
2346
2347 @Override
2348 public Type visitTypeVar(TypeVar t, Symbol sym) {
2349 return memberType(t.getUpperBound(), sym);
2350 }
2351
2352 @Override
2353 public Type visitErrorType(ErrorType t, Symbol sym) {
2354 return t;
2355 }
2356 };
2357 // </editor-fold>
2358
2359 // <editor-fold defaultstate="collapsed" desc="isAssignable">
2360 public boolean isAssignable(Type t, Type s) {
2361 return isAssignable(t, s, noWarnings);
2362 }
2363
2364 /**
2365 * Is t assignable to s?<br>
2366 * Equivalent to subtype except for constant values and raw
2367 * types.<br>
2368 * (not defined for Method and ForAll types)
2369 */
2370 public boolean isAssignable(Type t, Type s, Warner warn) {
2371 if (t.hasTag(ERROR))
2372 return true;
2373 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) {
2374 int value = ((Number)t.constValue()).intValue();
2375 switch (s.getTag()) {
2376 case BYTE:
2377 case CHAR:
2378 case SHORT:
2379 case INT:
2380 if (s.getTag().checkRange(value))
2381 return true;
2382 break;
2383 case CLASS:
2384 switch (unboxedType(s).getTag()) {
2385 case BYTE:
2386 case CHAR:
2387 case SHORT:
2388 return isAssignable(t, unboxedType(s), warn);
2389 }
2390 break;
2391 }
2392 }
2393 return isConvertible(t, s, warn);
2394 }
2395 // </editor-fold>
2396
2397 // <editor-fold defaultstate="collapsed" desc="erasure">
2398 /**
2399 * The erasure of t {@code |t|} -- the type that results when all
2400 * type parameters in t are deleted.
2401 */
2402 public Type erasure(Type t) {
2403 return eraseNotNeeded(t) ? t : erasure(t, false);
2404 }
2405 //where
2406 private boolean eraseNotNeeded(Type t) {
2407 // We don't want to erase primitive types and String type as that
2408 // operation is idempotent. Also, erasing these could result in loss
2409 // of information such as constant values attached to such types.
2410 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2411 }
2412
2413 private Type erasure(Type t, boolean recurse) {
2414 if (t.isPrimitive()) {
2415 return t; /* fast special case */
2416 } else {
2417 Type out = erasure.visit(t, recurse);
2418 return out;
2419 }
2420 }
2421 // where
2422 private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() {
2423 @SuppressWarnings("fallthrough")
2424 private Type combineMetadata(final Type s,
2425 final Type t) {
2426 if (t.getMetadata().nonEmpty()) {
2427 switch (s.getTag()) {
2428 case CLASS:
2429 if (s instanceof UnionClassType ||
2430 s instanceof IntersectionClassType) {
2431 return s;
2432 }
2433 //fall-through
2434 case BYTE, CHAR, SHORT, LONG, FLOAT, INT, DOUBLE, BOOLEAN,
2435 ARRAY, MODULE, TYPEVAR, WILDCARD, BOT:
2436 return s.dropMetadata(Annotations.class);
2437 case VOID, METHOD, PACKAGE, FORALL, DEFERRED,
2438 NONE, ERROR, UNDETVAR, UNINITIALIZED_THIS,
2439 UNINITIALIZED_OBJECT:
2440 return s;
2441 default:
2442 throw new AssertionError(s.getTag().name());
2443 }
2444 } else {
2445 return s;
2446 }
2447 }
2448
2449 public Type visitType(Type t, Boolean recurse) {
2450 if (t.isPrimitive())
2451 return t; /*fast special case*/
2452 else {
2453 //other cases already handled
2454 return combineMetadata(t, t);
2455 }
2456 }
2457
2458 @Override
2459 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2460 Type erased = erasure(wildUpperBound(t), recurse);
2461 return combineMetadata(erased, t);
2462 }
2463
2464 @Override
2465 public Type visitClassType(ClassType t, Boolean recurse) {
2466 Type erased = t.tsym.erasure(Types.this);
2467 if (recurse) {
2468 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym,
2469 t.dropMetadata(Annotations.class).getMetadata());
2470 return erased;
2471 } else {
2472 return combineMetadata(erased, t);
2473 }
2474 }
2475
2476 @Override
2477 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2478 Type erased = erasure(t.getUpperBound(), recurse);
2479 return combineMetadata(erased, t);
2480 }
2481 };
2482
2483 public List<Type> erasure(List<Type> ts) {
2484 return erasure.visit(ts, false);
2485 }
2486
2487 public Type erasureRecursive(Type t) {
2488 return erasure(t, true);
2489 }
2490
2491 public List<Type> erasureRecursive(List<Type> ts) {
2492 return erasure.visit(ts, true);
2493 }
2494 // </editor-fold>
2495
2496 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType">
2497 /**
2498 * Make an intersection type from non-empty list of types. The list should be ordered according to
2499 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion.
2500 * Hence, this version of makeIntersectionType may not be called during a classfile read.
2501 *
2502 * @param bounds the types from which the intersection type is formed
2503 */
2504 public IntersectionClassType makeIntersectionType(List<Type> bounds) {
2505 return makeIntersectionType(bounds, bounds.head.tsym.isInterface());
2506 }
2507
2508 /**
2509 * Make an intersection type from non-empty list of types. The list should be ordered according to
2510 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as
2511 * an extra parameter indicates as to whether all bounds are interfaces - in which case the
2512 * supertype is implicitly assumed to be 'Object'.
2513 *
2514 * @param bounds the types from which the intersection type is formed
2515 * @param allInterfaces are all bounds interface types?
2516 */
2517 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) {
2518 Assert.check(bounds.nonEmpty());
2519 Type firstExplicitBound = bounds.head;
2520 if (allInterfaces) {
2521 bounds = bounds.prepend(syms.objectType);
2522 }
2523 ClassSymbol bc =
2524 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2525 Type.moreInfo
2526 ? names.fromString(bounds.toString())
2527 : names.empty,
2528 null,
2529 syms.noSymbol);
2530 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces);
2531 bc.type = intersectionType;
2532 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
2533 syms.objectType : // error condition, recover
2534 erasure(firstExplicitBound);
2535 bc.members_field = WriteableScope.create(bc);
2536 return intersectionType;
2537 }
2538 // </editor-fold>
2539
2540 // <editor-fold defaultstate="collapsed" desc="supertype">
2541 public Type supertype(Type t) {
2542 return supertype.visit(t);
2543 }
2544 // where
2545 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2546
2547 public Type visitType(Type t, Void ignored) {
2548 // A note on wildcards: there is no good way to
2549 // determine a supertype for a lower-bounded wildcard.
2550 return Type.noType;
2551 }
2552
2553 @Override
2554 public Type visitClassType(ClassType t, Void ignored) {
2555 if (t.supertype_field == null) {
2556 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2557 // An interface has no superclass; its supertype is Object.
2558 if (t.isInterface())
2559 supertype = ((ClassType)t.tsym.type).supertype_field;
2560 if (t.supertype_field == null) {
2561 List<Type> actuals = classBound(t).allparams();
2562 List<Type> formals = t.tsym.type.allparams();
2563 if (t.hasErasedSupertypes()) {
2564 t.supertype_field = erasureRecursive(supertype);
2565 } else if (formals.nonEmpty()) {
2566 t.supertype_field = subst(supertype, formals, actuals);
2567 }
2568 else {
2569 t.supertype_field = supertype;
2570 }
2571 }
2572 }
2573 return t.supertype_field;
2574 }
2575
2576 /**
2577 * The supertype is always a class type. If the type
2578 * variable's bounds start with a class type, this is also
2579 * the supertype. Otherwise, the supertype is
2580 * java.lang.Object.
2581 */
2582 @Override
2583 public Type visitTypeVar(TypeVar t, Void ignored) {
2584 if (t.getUpperBound().hasTag(TYPEVAR) ||
2585 (!t.getUpperBound().isCompound() && !t.getUpperBound().isInterface())) {
2586 return t.getUpperBound();
2587 } else {
2588 return supertype(t.getUpperBound());
2589 }
2590 }
2591
2592 @Override
2593 public Type visitArrayType(ArrayType t, Void ignored) {
2594 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2595 return arraySuperType();
2596 else
2597 return new ArrayType(supertype(t.elemtype), t.tsym);
2598 }
2599
2600 @Override
2601 public Type visitErrorType(ErrorType t, Void ignored) {
2602 return Type.noType;
2603 }
2604 };
2605 // </editor-fold>
2606
2607 // <editor-fold defaultstate="collapsed" desc="interfaces">
2608 /**
2609 * Return the interfaces implemented by this class.
2610 */
2611 public List<Type> interfaces(Type t) {
2612 return interfaces.visit(t);
2613 }
2614 // where
2615 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2616
2617 public List<Type> visitType(Type t, Void ignored) {
2618 return List.nil();
2619 }
2620
2621 @Override
2622 public List<Type> visitClassType(ClassType t, Void ignored) {
2623 if (t.interfaces_field == null) {
2624 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2625 if (t.interfaces_field == null) {
2626 // If t.interfaces_field is null, then t must
2627 // be a parameterized type (not to be confused
2628 // with a generic type declaration).
2629 // Terminology:
2630 // Parameterized type: List<String>
2631 // Generic type declaration: class List<E> { ... }
2632 // So t corresponds to List<String> and
2633 // t.tsym.type corresponds to List<E>.
2634 // The reason t must be parameterized type is
2635 // that completion will happen as a side
2636 // effect of calling
2637 // ClassSymbol.getInterfaces. Since
2638 // t.interfaces_field is null after
2639 // completion, we can assume that t is not the
2640 // type of a class/interface declaration.
2641 Assert.check(t != t.tsym.type, t);
2642 List<Type> actuals = t.allparams();
2643 List<Type> formals = t.tsym.type.allparams();
2644 if (t.hasErasedSupertypes()) {
2645 t.interfaces_field = erasureRecursive(interfaces);
2646 } else if (formals.nonEmpty()) {
2647 t.interfaces_field = subst(interfaces, formals, actuals);
2648 }
2649 else {
2650 t.interfaces_field = interfaces;
2651 }
2652 }
2653 }
2654 return t.interfaces_field;
2655 }
2656
2657 @Override
2658 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2659 if (t.getUpperBound().isCompound())
2660 return interfaces(t.getUpperBound());
2661
2662 if (t.getUpperBound().isInterface())
2663 return List.of(t.getUpperBound());
2664
2665 return List.nil();
2666 }
2667 };
2668
2669 public List<Type> directSupertypes(Type t) {
2670 return directSupertypes.visit(t);
2671 }
2672 // where
2673 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() {
2674
2675 public List<Type> visitType(final Type type, final Void ignored) {
2676 if (!type.isIntersection()) {
2677 final Type sup = supertype(type);
2678 return (sup == Type.noType || sup == type || sup == null)
2679 ? interfaces(type)
2680 : interfaces(type).prepend(sup);
2681 } else {
2682 return ((IntersectionClassType)type).getExplicitComponents();
2683 }
2684 }
2685 };
2686
2687 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2688 for (Type i2 : interfaces(origin.type)) {
2689 if (isym == i2.tsym) return true;
2690 }
2691 return false;
2692 }
2693 // </editor-fold>
2694
2695 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2696 Map<Type,Boolean> isDerivedRawCache = new HashMap<>();
2697
2698 public boolean isDerivedRaw(Type t) {
2699 Boolean result = isDerivedRawCache.get(t);
2700 if (result == null) {
2701 result = isDerivedRawInternal(t);
2702 isDerivedRawCache.put(t, result);
2703 }
2704 return result;
2705 }
2706
2707 public boolean isDerivedRawInternal(Type t) {
2708 if (t.isErroneous())
2709 return false;
2710 return
2711 t.isRaw() ||
2712 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) ||
2713 isDerivedRaw(interfaces(t));
2714 }
2715
2716 public boolean isDerivedRaw(List<Type> ts) {
2717 List<Type> l = ts;
2718 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2719 return l.nonEmpty();
2720 }
2721 // </editor-fold>
2722
2723 // <editor-fold defaultstate="collapsed" desc="setBounds">
2724 /**
2725 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly,
2726 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise
2727 * the supertype is simply left null (in this case, the supertype is assumed to be the head of
2728 * the bound list passed as second argument). Note that this check might cause a symbol completion.
2729 * Hence, this version of setBounds may not be called during a classfile read.
2730 *
2731 * @param t a type variable
2732 * @param bounds the bounds, must be nonempty
2733 */
2734 public void setBounds(TypeVar t, List<Type> bounds) {
2735 setBounds(t, bounds, bounds.head.tsym.isInterface());
2736 }
2737
2738 /**
2739 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds.
2740 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds
2741 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'.
2742 *
2743 * @param t a type variable
2744 * @param bounds the bounds, must be nonempty
2745 * @param allInterfaces are all bounds interface types?
2746 */
2747 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2748 t.setUpperBound( bounds.tail.isEmpty() ?
2749 bounds.head :
2750 makeIntersectionType(bounds, allInterfaces) );
2751 t.rank_field = -1;
2752 }
2753 // </editor-fold>
2754
2755 // <editor-fold defaultstate="collapsed" desc="getBounds">
2756 /**
2757 * Return list of bounds of the given type variable.
2758 */
2759 public List<Type> getBounds(TypeVar t) {
2760 if (t.getUpperBound().hasTag(NONE))
2761 return List.nil();
2762 else if (t.getUpperBound().isErroneous() || !t.getUpperBound().isCompound())
2763 return List.of(t.getUpperBound());
2764 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2765 return interfaces(t).prepend(supertype(t));
2766 else
2767 // No superclass was given in bounds.
2768 // In this case, supertype is Object, erasure is first interface.
2769 return interfaces(t);
2770 }
2771 // </editor-fold>
2772
2773 // <editor-fold defaultstate="collapsed" desc="classBound">
2774 /**
2775 * If the given type is a (possibly selected) type variable,
2776 * return the bounding class of this type, otherwise return the
2777 * type itself.
2778 */
2779 public Type classBound(Type t) {
2780 return classBound.visit(t);
2781 }
2782 // where
2783 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2784
2785 public Type visitType(Type t, Void ignored) {
2786 return t;
2787 }
2788
2789 @Override
2790 public Type visitClassType(ClassType t, Void ignored) {
2791 Type outer1 = classBound(t.getEnclosingType());
2792 if (outer1 != t.getEnclosingType())
2793 return new ClassType(outer1, t.getTypeArguments(), t.tsym,
2794 t.getMetadata());
2795 else
2796 return t;
2797 }
2798
2799 @Override
2800 public Type visitTypeVar(TypeVar t, Void ignored) {
2801 return classBound(supertype(t));
2802 }
2803
2804 @Override
2805 public Type visitErrorType(ErrorType t, Void ignored) {
2806 return t;
2807 }
2808 };
2809 // </editor-fold>
2810
2811 // <editor-fold defaultstate="collapsed" desc="subsignature / override equivalence">
2812 /**
2813 * Returns true iff the first signature is a <em>subsignature</em>
2814 * of the other. This is <b>not</b> an equivalence
2815 * relation.
2816 *
2817 * @jls 8.4.2 Method Signature
2818 * @see #overrideEquivalent(Type t, Type s)
2819 * @param t first signature (possibly raw).
2820 * @param s second signature (could be subjected to erasure).
2821 * @return true if t is a subsignature of s.
2822 */
2823 public boolean isSubSignature(Type t, Type s) {
2824 return hasSameArgs(t, s, true) || hasSameArgs(t, erasure(s), true);
2825 }
2826
2827 /**
2828 * Returns true iff these signatures are related by <em>override
2829 * equivalence</em>. This is the natural extension of
2830 * isSubSignature to an equivalence relation.
2831 *
2832 * @jls 8.4.2 Method Signature
2833 * @see #isSubSignature(Type t, Type s)
2834 * @param t a signature (possible raw, could be subjected to
2835 * erasure).
2836 * @param s a signature (possible raw, could be subjected to
2837 * erasure).
2838 * @return true if either argument is a subsignature of the other.
2839 */
2840 public boolean overrideEquivalent(Type t, Type s) {
2841 return hasSameArgs(t, s) ||
2842 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2843 }
2844
2845 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2846 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) {
2847 if (msym.overrides(sym, origin, Types.this, true)) {
2848 return true;
2849 }
2850 }
2851 return false;
2852 }
2853
2854 /**
2855 * This enum defines the strategy for implementing most specific return type check
2856 * during the most specific and functional interface checks.
2857 */
2858 public enum MostSpecificReturnCheck {
2859 /**
2860 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling
2861 * method type variables (if either method is generic) and (ii) subtyping should be replaced
2862 * by type-equivalence for primitives. This is essentially an inlined version of
2863 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been
2864 * replaced with a strict subtyping check.
2865 */
2866 BASIC() {
2867 @Override
2868 public boolean test(Type mt1, Type mt2, Types types) {
2869 List<Type> tvars = mt1.getTypeArguments();
2870 List<Type> svars = mt2.getTypeArguments();
2871 Type t = mt1.getReturnType();
2872 Type s = types.subst(mt2.getReturnType(), svars, tvars);
2873 return types.isSameType(t, s) ||
2874 !t.isPrimitive() &&
2875 !s.isPrimitive() &&
2876 types.isSubtype(t, s);
2877 }
2878 },
2879 /**
2880 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2.
2881 */
2882 RTS() {
2883 @Override
2884 public boolean test(Type mt1, Type mt2, Types types) {
2885 return types.returnTypeSubstitutable(mt1, mt2);
2886 }
2887 };
2888
2889 public abstract boolean test(Type mt1, Type mt2, Types types);
2890 }
2891
2892 /**
2893 * Merge multiple abstract methods. The preferred method is a method that is a subsignature
2894 * of all the other signatures and whose return type is more specific {@link MostSpecificReturnCheck}.
2895 * The resulting preferred method has a throws clause that is the intersection of the merged
2896 * methods' clauses.
2897 */
2898 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) {
2899 //first check for preconditions
2900 boolean shouldErase = false;
2901 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes();
2902 for (Symbol s : ambiguousInOrder) {
2903 if ((s.flags() & ABSTRACT) == 0 ||
2904 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) {
2905 return Optional.empty();
2906 } else if (s.type.hasTag(FORALL)) {
2907 shouldErase = true;
2908 }
2909 }
2910 //then merge abstracts
2911 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) {
2912 outer: for (Symbol s : ambiguousInOrder) {
2913 Type mt = memberType(site, s);
2914 List<Type> allThrown = mt.getThrownTypes();
2915 for (Symbol s2 : ambiguousInOrder) {
2916 if (s != s2) {
2917 Type mt2 = memberType(site, s2);
2918 if (!isSubSignature(mt, mt2) ||
2919 !mostSpecificReturnCheck.test(mt, mt2, this)) {
2920 //ambiguity cannot be resolved
2921 continue outer;
2922 } else {
2923 List<Type> thrownTypes2 = mt2.getThrownTypes();
2924 if (!mt.hasTag(FORALL) && shouldErase) {
2925 thrownTypes2 = erasure(thrownTypes2);
2926 } else if (mt.hasTag(FORALL)) {
2927 //subsignature implies that if most specific is generic, then all other
2928 //methods are too
2929 Assert.check(mt2.hasTag(FORALL));
2930 // if both are generic methods, adjust thrown types ahead of intersection computation
2931 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments());
2932 }
2933 allThrown = chk.intersect(allThrown, thrownTypes2);
2934 }
2935 }
2936 }
2937 return (allThrown == mt.getThrownTypes()) ?
2938 Optional.of(s) :
2939 Optional.of(new MethodSymbol(
2940 s.flags(),
2941 s.name,
2942 createMethodTypeWithThrown(s.type, allThrown),
2943 s.owner) {
2944 @Override
2945 public Symbol baseSymbol() {
2946 return s;
2947 }
2948 });
2949 }
2950 }
2951 return Optional.empty();
2952 }
2953
2954 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2955 class ImplementationCache {
2956
2957 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>();
2958
2959 class Entry {
2960 final MethodSymbol cachedImpl;
2961 final Predicate<Symbol> implFilter;
2962 final boolean checkResult;
2963 final int prevMark;
2964
2965 public Entry(MethodSymbol cachedImpl,
2966 Predicate<Symbol> scopeFilter,
2967 boolean checkResult,
2968 int prevMark) {
2969 this.cachedImpl = cachedImpl;
2970 this.implFilter = scopeFilter;
2971 this.checkResult = checkResult;
2972 this.prevMark = prevMark;
2973 }
2974
2975 boolean matches(Predicate<Symbol> scopeFilter, boolean checkResult, int mark) {
2976 return this.implFilter == scopeFilter &&
2977 this.checkResult == checkResult &&
2978 this.prevMark == mark;
2979 }
2980 }
2981
2982 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
2983 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2984 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2985 if (cache == null) {
2986 cache = new HashMap<>();
2987 _map.put(ms, new SoftReference<>(cache));
2988 }
2989 Entry e = cache.get(origin);
2990 CompoundScope members = membersClosure(origin.type, true);
2991 if (e == null ||
2992 !e.matches(implFilter, checkResult, members.getMark())) {
2993 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2994 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2995 return impl;
2996 }
2997 else {
2998 return e.cachedImpl;
2999 }
3000 }
3001
3002 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
3003 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
3004 t = skipTypeVars(t, false);
3005 TypeSymbol c = t.tsym;
3006 Symbol bestSoFar = null;
3007 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) {
3008 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) {
3009 bestSoFar = sym;
3010 if ((sym.flags() & ABSTRACT) == 0) {
3011 //if concrete impl is found, exit immediately
3012 break;
3013 }
3014 }
3015 }
3016 if (bestSoFar != null) {
3017 //return either the (only) concrete implementation or the first abstract one
3018 return (MethodSymbol)bestSoFar;
3019 }
3020 }
3021 return null;
3022 }
3023 }
3024
3025 private ImplementationCache implCache = new ImplementationCache();
3026
3027 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) {
3028 return implCache.get(ms, origin, checkResult, implFilter);
3029 }
3030 // </editor-fold>
3031
3032 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
3033 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> {
3034
3035 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>();
3036
3037 Set<TypeSymbol> seenTypes = new HashSet<>();
3038
3039 class MembersScope extends CompoundScope {
3040
3041 CompoundScope scope;
3042
3043 public MembersScope(CompoundScope scope) {
3044 super(scope.owner);
3045 this.scope = scope;
3046 }
3047
3048 Predicate<Symbol> combine(Predicate<Symbol> sf) {
3049 return s -> !s.owner.isInterface() && (sf == null || sf.test(s));
3050 }
3051
3052 @Override
3053 public Iterable<Symbol> getSymbols(Predicate<Symbol> sf, LookupKind lookupKind) {
3054 return scope.getSymbols(combine(sf), lookupKind);
3055 }
3056
3057 @Override
3058 public Iterable<Symbol> getSymbolsByName(Name name, Predicate<Symbol> sf, LookupKind lookupKind) {
3059 return scope.getSymbolsByName(name, combine(sf), lookupKind);
3060 }
3061
3062 @Override
3063 public int getMark() {
3064 return scope.getMark();
3065 }
3066 }
3067
3068 CompoundScope nilScope;
3069
3070 /** members closure visitor methods **/
3071
3072 public CompoundScope visitType(Type t, Void _unused) {
3073 if (nilScope == null) {
3074 nilScope = new CompoundScope(syms.noSymbol);
3075 }
3076 return nilScope;
3077 }
3078
3079 @Override
3080 public CompoundScope visitClassType(ClassType t, Void _unused) {
3081 if (!seenTypes.add(t.tsym)) {
3082 //this is possible when an interface is implemented in multiple
3083 //superclasses, or when a class hierarchy is circular - in such
3084 //cases we don't need to recurse (empty scope is returned)
3085 return new CompoundScope(t.tsym);
3086 }
3087 try {
3088 seenTypes.add(t.tsym);
3089 ClassSymbol csym = (ClassSymbol)t.tsym;
3090 CompoundScope membersClosure = _map.get(csym);
3091 if (membersClosure == null) {
3092 membersClosure = new CompoundScope(csym);
3093 for (Type i : interfaces(t)) {
3094 membersClosure.prependSubScope(visit(i, null));
3095 }
3096 membersClosure.prependSubScope(visit(supertype(t), null));
3097 membersClosure.prependSubScope(csym.members());
3098 _map.put(csym, membersClosure);
3099 }
3100 return membersClosure;
3101 }
3102 finally {
3103 seenTypes.remove(t.tsym);
3104 }
3105 }
3106
3107 @Override
3108 public CompoundScope visitTypeVar(TypeVar t, Void _unused) {
3109 return visit(t.getUpperBound(), null);
3110 }
3111 }
3112
3113 private MembersClosureCache membersCache = new MembersClosureCache();
3114
3115 public CompoundScope membersClosure(Type site, boolean skipInterface) {
3116 CompoundScope cs = membersCache.visit(site, null);
3117 Assert.checkNonNull(cs, () -> "type " + site);
3118 return skipInterface ? membersCache.new MembersScope(cs) : cs;
3119 }
3120 // </editor-fold>
3121
3122
3123 /** Return first abstract member of class `sym'.
3124 */
3125 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) {
3126 try {
3127 return firstUnimplementedAbstractImpl(sym, sym);
3128 } catch (CompletionFailure ex) {
3129 chk.completionError(enter.getEnv(sym).tree.pos(), ex);
3130 return null;
3131 }
3132 }
3133 //where:
3134 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) {
3135 MethodSymbol undef = null;
3136 // Do not bother to search in classes that are not abstract,
3137 // since they cannot have abstract members.
3138 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
3139 Scope s = c.members();
3140 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
3141 if (sym.kind == MTH &&
3142 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
3143 MethodSymbol absmeth = (MethodSymbol)sym;
3144 MethodSymbol implmeth = absmeth.implementation(impl, this, true);
3145 if (implmeth == null || implmeth == absmeth) {
3146 //look for default implementations
3147 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head;
3148 if (prov != null && prov.overrides(absmeth, impl, this, true)) {
3149 implmeth = prov;
3150 }
3151 }
3152 if (implmeth == null || implmeth == absmeth) {
3153 undef = absmeth;
3154 break;
3155 }
3156 }
3157 }
3158 if (undef == null) {
3159 Type st = supertype(c.type);
3160 if (st.hasTag(CLASS))
3161 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym);
3162 }
3163 for (List<Type> l = interfaces(c.type);
3164 undef == null && l.nonEmpty();
3165 l = l.tail) {
3166 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym);
3167 }
3168 }
3169 return undef;
3170 }
3171
3172 public class CandidatesCache {
3173 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>();
3174
3175 class Entry {
3176 Type site;
3177 MethodSymbol msym;
3178
3179 Entry(Type site, MethodSymbol msym) {
3180 this.site = site;
3181 this.msym = msym;
3182 }
3183
3184 @Override
3185 public boolean equals(Object obj) {
3186 return (obj instanceof Entry entry)
3187 && entry.msym == msym
3188 && isSameType(site, entry.site);
3189 }
3190
3191 @Override
3192 public int hashCode() {
3193 return Types.this.hashCode(site) & ~msym.hashCode();
3194 }
3195 }
3196
3197 public List<MethodSymbol> get(Entry e) {
3198 return cache.get(e);
3199 }
3200
3201 public void put(Entry e, List<MethodSymbol> msymbols) {
3202 cache.put(e, msymbols);
3203 }
3204 }
3205
3206 public CandidatesCache candidatesCache = new CandidatesCache();
3207
3208 //where
3209 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
3210 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms);
3211 List<MethodSymbol> candidates = candidatesCache.get(e);
3212 if (candidates == null) {
3213 Predicate<Symbol> filter = new MethodFilter(ms, site);
3214 List<MethodSymbol> candidates2 = List.nil();
3215 for (Symbol s : membersClosure(site, false).getSymbols(filter)) {
3216 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
3217 return List.of((MethodSymbol)s);
3218 } else if (!candidates2.contains(s)) {
3219 candidates2 = candidates2.prepend((MethodSymbol)s);
3220 }
3221 }
3222 candidates = prune(candidates2);
3223 candidatesCache.put(e, candidates);
3224 }
3225 return candidates;
3226 }
3227
3228 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
3229 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>();
3230 for (MethodSymbol m1 : methods) {
3231 boolean isMin_m1 = true;
3232 for (MethodSymbol m2 : methods) {
3233 if (m1 == m2) continue;
3234 if (m2.owner != m1.owner &&
3235 asSuper(m2.owner.type, m1.owner) != null) {
3236 isMin_m1 = false;
3237 break;
3238 }
3239 }
3240 if (isMin_m1)
3241 methodsMin.append(m1);
3242 }
3243 return methodsMin.toList();
3244 }
3245 // where
3246 private class MethodFilter implements Predicate<Symbol> {
3247
3248 Symbol msym;
3249 Type site;
3250
3251 MethodFilter(Symbol msym, Type site) {
3252 this.msym = msym;
3253 this.site = site;
3254 }
3255
3256 @Override
3257 public boolean test(Symbol s) {
3258 return s.kind == MTH &&
3259 s.name == msym.name &&
3260 (s.flags() & SYNTHETIC) == 0 &&
3261 s.isInheritedIn(site.tsym, Types.this) &&
3262 overrideEquivalent(memberType(site, s), memberType(site, msym));
3263 }
3264 }
3265 // </editor-fold>
3266
3267 /**
3268 * Does t have the same arguments as s? It is assumed that both
3269 * types are (possibly polymorphic) method types. Monomorphic
3270 * method types "have the same arguments", if their argument lists
3271 * are equal. Polymorphic method types "have the same arguments",
3272 * if they have the same arguments after renaming all type
3273 * variables of one to corresponding type variables in the other,
3274 * where correspondence is by position in the type parameter list.
3275 */
3276 public boolean hasSameArgs(Type t, Type s) {
3277 return hasSameArgs(t, s, true);
3278 }
3279
3280 public boolean hasSameArgs(Type t, Type s, boolean strict) {
3281 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
3282 }
3283
3284 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
3285 return hasSameArgs.visit(t, s);
3286 }
3287 // where
3288 private class HasSameArgs extends TypeRelation {
3289
3290 boolean strict;
3291
3292 public HasSameArgs(boolean strict) {
3293 this.strict = strict;
3294 }
3295
3296 public Boolean visitType(Type t, Type s) {
3297 throw new AssertionError();
3298 }
3299
3300 @Override
3301 public Boolean visitMethodType(MethodType t, Type s) {
3302 return s.hasTag(METHOD)
3303 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
3304 }
3305
3306 @Override
3307 public Boolean visitForAll(ForAll t, Type s) {
3308 if (!s.hasTag(FORALL))
3309 return strict ? false : visitMethodType(t.asMethodType(), s);
3310
3311 ForAll forAll = (ForAll)s;
3312 return hasSameBounds(t, forAll)
3313 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
3314 }
3315
3316 @Override
3317 public Boolean visitErrorType(ErrorType t, Type s) {
3318 return false;
3319 }
3320 }
3321
3322 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
3323 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
3324
3325 // </editor-fold>
3326
3327 // <editor-fold defaultstate="collapsed" desc="subst">
3328 public List<Type> subst(List<Type> ts,
3329 List<Type> from,
3330 List<Type> to) {
3331 return ts.map(new Subst(from, to));
3332 }
3333
3334 /**
3335 * Substitute all occurrences of a type in `from' with the
3336 * corresponding type in `to' in 't'. Match lists `from' and `to'
3337 * from the right: If lists have different length, discard leading
3338 * elements of the longer list.
3339 */
3340 public Type subst(Type t, List<Type> from, List<Type> to) {
3341 return t.map(new Subst(from, to));
3342 }
3343
3344 /* this class won't substitute all types for example UndetVars are never substituted, this is
3345 * by design as UndetVars are used locally during inference and shouldn't escape from inference routines,
3346 * some specialized applications could need a tailored solution
3347 */
3348 private class Subst extends StructuralTypeMapping<Void> {
3349 List<Type> from;
3350 List<Type> to;
3351
3352 public Subst(List<Type> from, List<Type> to) {
3353 int fromLength = from.length();
3354 int toLength = to.length();
3355 while (fromLength > toLength) {
3356 fromLength--;
3357 from = from.tail;
3358 }
3359 while (fromLength < toLength) {
3360 toLength--;
3361 to = to.tail;
3362 }
3363 this.from = from;
3364 this.to = to;
3365 }
3366
3367 @Override
3368 public Type visitTypeVar(TypeVar t, Void ignored) {
3369 for (List<Type> from = this.from, to = this.to;
3370 from.nonEmpty();
3371 from = from.tail, to = to.tail) {
3372 if (t.equalsIgnoreMetadata(from.head)) {
3373 return to.head.withTypeVar(t);
3374 }
3375 }
3376 return t;
3377 }
3378
3379 @Override
3380 public Type visitClassType(ClassType t, Void ignored) {
3381 if (!t.isCompound()) {
3382 return super.visitClassType(t, ignored);
3383 } else {
3384 Type st = visit(supertype(t));
3385 List<Type> is = visit(interfaces(t), ignored);
3386 if (st == supertype(t) && is == interfaces(t))
3387 return t;
3388 else
3389 return makeIntersectionType(is.prepend(st));
3390 }
3391 }
3392
3393 @Override
3394 public Type visitWildcardType(WildcardType t, Void ignored) {
3395 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored);
3396 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) {
3397 t2.type = wildUpperBound(t2.type);
3398 }
3399 return t2;
3400 }
3401
3402 @Override
3403 public Type visitForAll(ForAll t, Void ignored) {
3404 if (Type.containsAny(to, t.tvars)) {
3405 //perform alpha-renaming of free-variables in 't'
3406 //if 'to' types contain variables that are free in 't'
3407 List<Type> freevars = newInstances(t.tvars);
3408 t = new ForAll(freevars,
3409 Types.this.subst(t.qtype, t.tvars, freevars));
3410 }
3411 List<Type> tvars1 = substBounds(t.tvars, from, to);
3412 Type qtype1 = visit(t.qtype);
3413 if (tvars1 == t.tvars && qtype1 == t.qtype) {
3414 return t;
3415 } else if (tvars1 == t.tvars) {
3416 return new ForAll(tvars1, qtype1) {
3417 @Override
3418 public boolean needsStripping() {
3419 return true;
3420 }
3421 };
3422 } else {
3423 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) {
3424 @Override
3425 public boolean needsStripping() {
3426 return true;
3427 }
3428 };
3429 }
3430 }
3431 }
3432
3433 public List<Type> substBounds(List<Type> tvars,
3434 List<Type> from,
3435 List<Type> to) {
3436 if (tvars.isEmpty())
3437 return tvars;
3438 ListBuffer<Type> newBoundsBuf = new ListBuffer<>();
3439 boolean changed = false;
3440 // calculate new bounds
3441 for (Type t : tvars) {
3442 TypeVar tv = (TypeVar) t;
3443 Type bound = subst(tv.getUpperBound(), from, to);
3444 if (bound != tv.getUpperBound())
3445 changed = true;
3446 newBoundsBuf.append(bound);
3447 }
3448 if (!changed)
3449 return tvars;
3450 ListBuffer<Type> newTvars = new ListBuffer<>();
3451 // create new type variables without bounds
3452 for (Type t : tvars) {
3453 newTvars.append(new TypeVar(t.tsym, null, syms.botType,
3454 t.getMetadata()));
3455 }
3456 // the new bounds should use the new type variables in place
3457 // of the old
3458 List<Type> newBounds = newBoundsBuf.toList();
3459 from = tvars;
3460 to = newTvars.toList();
3461 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
3462 newBounds.head = subst(newBounds.head, from, to);
3463 }
3464 newBounds = newBoundsBuf.toList();
3465 // set the bounds of new type variables to the new bounds
3466 for (Type t : newTvars.toList()) {
3467 TypeVar tv = (TypeVar) t;
3468 tv.setUpperBound( newBounds.head );
3469 newBounds = newBounds.tail;
3470 }
3471 return newTvars.toList();
3472 }
3473
3474 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
3475 Type bound1 = subst(t.getUpperBound(), from, to);
3476 if (bound1 == t.getUpperBound())
3477 return t;
3478 else {
3479 // create new type variable without bounds
3480 TypeVar tv = new TypeVar(t.tsym, null, syms.botType,
3481 t.getMetadata());
3482 // the new bound should use the new type variable in place
3483 // of the old
3484 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) );
3485 return tv;
3486 }
3487 }
3488 // </editor-fold>
3489
3490 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
3491 /**
3492 * Does t have the same bounds for quantified variables as s?
3493 */
3494 public boolean hasSameBounds(ForAll t, ForAll s) {
3495 List<Type> l1 = t.tvars;
3496 List<Type> l2 = s.tvars;
3497 while (l1.nonEmpty() && l2.nonEmpty() &&
3498 isSameType(l1.head.getUpperBound(),
3499 subst(l2.head.getUpperBound(),
3500 s.tvars,
3501 t.tvars))) {
3502 l1 = l1.tail;
3503 l2 = l2.tail;
3504 }
3505 return l1.isEmpty() && l2.isEmpty();
3506 }
3507 // </editor-fold>
3508
3509 // <editor-fold defaultstate="collapsed" desc="newInstances">
3510 /** Create new vector of type variables from list of variables
3511 * changing all recursive bounds from old to new list.
3512 */
3513 public List<Type> newInstances(List<Type> tvars) {
3514 List<Type> tvars1 = tvars.map(newInstanceFun);
3515 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
3516 TypeVar tv = (TypeVar) l.head;
3517 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) );
3518 }
3519 return tvars1;
3520 }
3521 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() {
3522 @Override
3523 public TypeVar visitTypeVar(TypeVar t, Void _unused) {
3524 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata());
3525 }
3526 };
3527 // </editor-fold>
3528
3529 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
3530 return original.accept(methodWithParameters, newParams);
3531 }
3532 // where
3533 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
3534 public Type visitType(Type t, List<Type> newParams) {
3535 throw new IllegalArgumentException("Not a method type: " + t);
3536 }
3537 public Type visitMethodType(MethodType t, List<Type> newParams) {
3538 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
3539 }
3540 public Type visitForAll(ForAll t, List<Type> newParams) {
3541 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
3542 }
3543 };
3544
3545 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
3546 return original.accept(methodWithThrown, newThrown);
3547 }
3548 // where
3549 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
3550 public Type visitType(Type t, List<Type> newThrown) {
3551 throw new IllegalArgumentException("Not a method type: " + t);
3552 }
3553 public Type visitMethodType(MethodType t, List<Type> newThrown) {
3554 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
3555 }
3556 public Type visitForAll(ForAll t, List<Type> newThrown) {
3557 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
3558 }
3559 };
3560
3561 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
3562 return original.accept(methodWithReturn, newReturn);
3563 }
3564 // where
3565 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
3566 public Type visitType(Type t, Type newReturn) {
3567 throw new IllegalArgumentException("Not a method type: " + t);
3568 }
3569 public Type visitMethodType(MethodType t, Type newReturn) {
3570 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) {
3571 @Override
3572 public Type baseType() {
3573 return t;
3574 }
3575 };
3576 }
3577 public Type visitForAll(ForAll t, Type newReturn) {
3578 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) {
3579 @Override
3580 public Type baseType() {
3581 return t;
3582 }
3583 };
3584 }
3585 };
3586
3587 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3588 public Type createErrorType(Type originalType) {
3589 return new ErrorType(originalType, syms.errSymbol);
3590 }
3591
3592 public Type createErrorType(ClassSymbol c, Type originalType) {
3593 return new ErrorType(c, originalType);
3594 }
3595
3596 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3597 return new ErrorType(name, container, originalType);
3598 }
3599 // </editor-fold>
3600
3601 // <editor-fold defaultstate="collapsed" desc="rank">
3602 /**
3603 * The rank of a class is the length of the longest path between
3604 * the class and java.lang.Object in the class inheritance
3605 * graph. Undefined for all but reference types.
3606 */
3607 public int rank(Type t) {
3608 switch(t.getTag()) {
3609 case CLASS: {
3610 ClassType cls = (ClassType)t;
3611 if (cls.rank_field < 0) {
3612 Name fullname = cls.tsym.getQualifiedName();
3613 if (fullname == names.java_lang_Object)
3614 cls.rank_field = 0;
3615 else {
3616 int r = rank(supertype(cls));
3617 for (List<Type> l = interfaces(cls);
3618 l.nonEmpty();
3619 l = l.tail) {
3620 if (rank(l.head) > r)
3621 r = rank(l.head);
3622 }
3623 cls.rank_field = r + 1;
3624 }
3625 }
3626 return cls.rank_field;
3627 }
3628 case TYPEVAR: {
3629 TypeVar tvar = (TypeVar)t;
3630 if (tvar.rank_field < 0) {
3631 int r = rank(supertype(tvar));
3632 for (List<Type> l = interfaces(tvar);
3633 l.nonEmpty();
3634 l = l.tail) {
3635 if (rank(l.head) > r) r = rank(l.head);
3636 }
3637 tvar.rank_field = r + 1;
3638 }
3639 return tvar.rank_field;
3640 }
3641 case ERROR:
3642 case NONE:
3643 return 0;
3644 default:
3645 throw new AssertionError();
3646 }
3647 }
3648 // </editor-fold>
3649
3650 /**
3651 * Helper method for generating a string representation of a given type
3652 * accordingly to a given locale
3653 */
3654 public String toString(Type t, Locale locale) {
3655 return Printer.createStandardPrinter(messages).visit(t, locale);
3656 }
3657
3658 /**
3659 * Helper method for generating a string representation of a given type
3660 * accordingly to a given locale
3661 */
3662 public String toString(Symbol t, Locale locale) {
3663 return Printer.createStandardPrinter(messages).visit(t, locale);
3664 }
3665
3666 // <editor-fold defaultstate="collapsed" desc="toString">
3667 /**
3668 * This toString is slightly more descriptive than the one on Type.
3669 *
3670 * @deprecated Types.toString(Type t, Locale l) provides better support
3671 * for localization
3672 */
3673 @Deprecated
3674 public String toString(Type t) {
3675 if (t.hasTag(FORALL)) {
3676 ForAll forAll = (ForAll)t;
3677 return typaramsString(forAll.tvars) + forAll.qtype;
3678 }
3679 return "" + t;
3680 }
3681 // where
3682 private String typaramsString(List<Type> tvars) {
3683 StringBuilder s = new StringBuilder();
3684 s.append('<');
3685 boolean first = true;
3686 for (Type t : tvars) {
3687 if (!first) s.append(", ");
3688 first = false;
3689 appendTyparamString(((TypeVar)t), s);
3690 }
3691 s.append('>');
3692 return s.toString();
3693 }
3694 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3695 buf.append(t);
3696 if (t.getUpperBound() == null ||
3697 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object)
3698 return;
3699 buf.append(" extends "); // Java syntax; no need for i18n
3700 Type bound = t.getUpperBound();
3701 if (!bound.isCompound()) {
3702 buf.append(bound);
3703 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3704 buf.append(supertype(t));
3705 for (Type intf : interfaces(t)) {
3706 buf.append('&');
3707 buf.append(intf);
3708 }
3709 } else {
3710 // No superclass was given in bounds.
3711 // In this case, supertype is Object, erasure is first interface.
3712 boolean first = true;
3713 for (Type intf : interfaces(t)) {
3714 if (!first) buf.append('&');
3715 first = false;
3716 buf.append(intf);
3717 }
3718 }
3719 }
3720 // </editor-fold>
3721
3722 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3723 /**
3724 * A cache for closures.
3725 *
3726 * <p>A closure is a list of all the supertypes and interfaces of
3727 * a class or interface type, ordered by ClassSymbol.precedes
3728 * (that is, subclasses come first, arbitrarily but fixed
3729 * otherwise).
3730 */
3731 private Map<Type,List<Type>> closureCache = new HashMap<>();
3732
3733 /**
3734 * Returns the closure of a class or interface type.
3735 */
3736 public List<Type> closure(Type t) {
3737 List<Type> cl = closureCache.get(t);
3738 if (cl == null) {
3739 Type st = supertype(t);
3740 if (!t.isCompound()) {
3741 if (st.hasTag(CLASS)) {
3742 cl = insert(closure(st), t);
3743 } else if (st.hasTag(TYPEVAR)) {
3744 cl = closure(st).prepend(t);
3745 } else {
3746 cl = List.of(t);
3747 }
3748 } else {
3749 cl = closure(supertype(t));
3750 }
3751 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3752 cl = union(cl, closure(l.head));
3753 closureCache.put(t, cl);
3754 }
3755 return cl;
3756 }
3757
3758 /**
3759 * Collect types into a new closure (using a {@code ClosureHolder})
3760 */
3761 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3762 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip),
3763 ClosureHolder::add,
3764 ClosureHolder::merge,
3765 ClosureHolder::closure);
3766 }
3767 //where
3768 class ClosureHolder {
3769 List<Type> closure;
3770 final boolean minClosure;
3771 final BiPredicate<Type, Type> shouldSkip;
3772
3773 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
3774 this.closure = List.nil();
3775 this.minClosure = minClosure;
3776 this.shouldSkip = shouldSkip;
3777 }
3778
3779 void add(Type type) {
3780 closure = insert(closure, type, shouldSkip);
3781 }
3782
3783 ClosureHolder merge(ClosureHolder other) {
3784 closure = union(closure, other.closure, shouldSkip);
3785 return this;
3786 }
3787
3788 List<Type> closure() {
3789 return minClosure ? closureMin(closure) : closure;
3790 }
3791 }
3792
3793 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym;
3794
3795 /**
3796 * Insert a type in a closure
3797 */
3798 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) {
3799 if (cl.isEmpty()) {
3800 return cl.prepend(t);
3801 } else if (shouldSkip.test(t, cl.head)) {
3802 return cl;
3803 } else if (t.tsym.precedes(cl.head.tsym, this)) {
3804 return cl.prepend(t);
3805 } else {
3806 // t comes after head, or the two are unrelated
3807 return insert(cl.tail, t, shouldSkip).prepend(cl.head);
3808 }
3809 }
3810
3811 public List<Type> insert(List<Type> cl, Type t) {
3812 return insert(cl, t, basicClosureSkip);
3813 }
3814
3815 /**
3816 * Form the union of two closures
3817 */
3818 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) {
3819 if (cl1.isEmpty()) {
3820 return cl2;
3821 } else if (cl2.isEmpty()) {
3822 return cl1;
3823 } else if (shouldSkip.test(cl1.head, cl2.head)) {
3824 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
3825 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3826 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
3827 } else {
3828 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
3829 }
3830 }
3831
3832 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3833 return union(cl1, cl2, basicClosureSkip);
3834 }
3835
3836 /**
3837 * Intersect two closures
3838 */
3839 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3840 if (cl1 == cl2)
3841 return cl1;
3842 if (cl1.isEmpty() || cl2.isEmpty())
3843 return List.nil();
3844 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3845 return intersect(cl1.tail, cl2);
3846 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3847 return intersect(cl1, cl2.tail);
3848 if (isSameType(cl1.head, cl2.head))
3849 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3850 if (cl1.head.tsym == cl2.head.tsym &&
3851 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) {
3852 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3853 Type merge = merge(cl1.head,cl2.head);
3854 return intersect(cl1.tail, cl2.tail).prepend(merge);
3855 }
3856 if (cl1.head.isRaw() || cl2.head.isRaw())
3857 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3858 }
3859 return intersect(cl1.tail, cl2.tail);
3860 }
3861 // where
3862 class TypePair {
3863 final Type t1;
3864 final Type t2;;
3865
3866 TypePair(Type t1, Type t2) {
3867 this.t1 = t1;
3868 this.t2 = t2;
3869 }
3870 @Override
3871 public int hashCode() {
3872 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3873 }
3874 @Override
3875 public boolean equals(Object obj) {
3876 return (obj instanceof TypePair typePair)
3877 && isSameType(t1, typePair.t1)
3878 && isSameType(t2, typePair.t2);
3879 }
3880 }
3881 Set<TypePair> mergeCache = new HashSet<>();
3882 private Type merge(Type c1, Type c2) {
3883 ClassType class1 = (ClassType) c1;
3884 List<Type> act1 = class1.getTypeArguments();
3885 ClassType class2 = (ClassType) c2;
3886 List<Type> act2 = class2.getTypeArguments();
3887 ListBuffer<Type> merged = new ListBuffer<>();
3888 List<Type> typarams = class1.tsym.type.getTypeArguments();
3889
3890 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3891 if (containsType(act1.head, act2.head)) {
3892 merged.append(act1.head);
3893 } else if (containsType(act2.head, act1.head)) {
3894 merged.append(act2.head);
3895 } else {
3896 TypePair pair = new TypePair(c1, c2);
3897 Type m;
3898 if (mergeCache.add(pair)) {
3899 m = new WildcardType(lub(wildUpperBound(act1.head),
3900 wildUpperBound(act2.head)),
3901 BoundKind.EXTENDS,
3902 syms.boundClass);
3903 mergeCache.remove(pair);
3904 } else {
3905 m = new WildcardType(syms.objectType,
3906 BoundKind.UNBOUND,
3907 syms.boundClass);
3908 }
3909 merged.append(m.withTypeVar(typarams.head));
3910 }
3911 act1 = act1.tail;
3912 act2 = act2.tail;
3913 typarams = typarams.tail;
3914 }
3915 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3916 // There is no spec detailing how type annotations are to
3917 // be inherited. So set it to noAnnotations for now
3918 return new ClassType(class1.getEnclosingType(), merged.toList(),
3919 class1.tsym, List.nil());
3920 }
3921
3922 /**
3923 * Return the minimum type of a closure, a compound type if no
3924 * unique minimum exists.
3925 */
3926 private Type compoundMin(List<Type> cl) {
3927 if (cl.isEmpty()) return syms.objectType;
3928 List<Type> compound = closureMin(cl);
3929 if (compound.isEmpty())
3930 return null;
3931 else if (compound.tail.isEmpty())
3932 return compound.head;
3933 else
3934 return makeIntersectionType(compound);
3935 }
3936
3937 /**
3938 * Return the minimum types of a closure, suitable for computing
3939 * compoundMin or glb.
3940 */
3941 private List<Type> closureMin(List<Type> cl) {
3942 ListBuffer<Type> classes = new ListBuffer<>();
3943 ListBuffer<Type> interfaces = new ListBuffer<>();
3944 Set<Type> toSkip = new HashSet<>();
3945 while (!cl.isEmpty()) {
3946 Type current = cl.head;
3947 boolean keep = !toSkip.contains(current);
3948 if (keep && current.hasTag(TYPEVAR)) {
3949 // skip lower-bounded variables with a subtype in cl.tail
3950 for (Type t : cl.tail) {
3951 if (isSubtypeNoCapture(t, current)) {
3952 keep = false;
3953 break;
3954 }
3955 }
3956 }
3957 if (keep) {
3958 if (current.isInterface())
3959 interfaces.append(current);
3960 else
3961 classes.append(current);
3962 for (Type t : cl.tail) {
3963 // skip supertypes of 'current' in cl.tail
3964 if (isSubtypeNoCapture(current, t))
3965 toSkip.add(t);
3966 }
3967 }
3968 cl = cl.tail;
3969 }
3970 return classes.appendList(interfaces).toList();
3971 }
3972
3973 /**
3974 * Return the least upper bound of list of types. if the lub does
3975 * not exist return null.
3976 */
3977 public Type lub(List<Type> ts) {
3978 return lub(ts.toArray(new Type[ts.length()]));
3979 }
3980
3981 /**
3982 * Return the least upper bound (lub) of set of types. If the lub
3983 * does not exist return the type of null (bottom).
3984 */
3985 public Type lub(Type... ts) {
3986 final int UNKNOWN_BOUND = 0;
3987 final int ARRAY_BOUND = 1;
3988 final int CLASS_BOUND = 2;
3989
3990 int[] kinds = new int[ts.length];
3991
3992 int boundkind = UNKNOWN_BOUND;
3993 for (int i = 0 ; i < ts.length ; i++) {
3994 Type t = ts[i];
3995 switch (t.getTag()) {
3996 case CLASS:
3997 boundkind |= kinds[i] = CLASS_BOUND;
3998 break;
3999 case ARRAY:
4000 boundkind |= kinds[i] = ARRAY_BOUND;
4001 break;
4002 case TYPEVAR:
4003 do {
4004 t = t.getUpperBound();
4005 } while (t.hasTag(TYPEVAR));
4006 if (t.hasTag(ARRAY)) {
4007 boundkind |= kinds[i] = ARRAY_BOUND;
4008 } else {
4009 boundkind |= kinds[i] = CLASS_BOUND;
4010 }
4011 break;
4012 default:
4013 kinds[i] = UNKNOWN_BOUND;
4014 if (t.isPrimitive())
4015 return syms.errType;
4016 }
4017 }
4018 switch (boundkind) {
4019 case 0:
4020 return syms.botType;
4021
4022 case ARRAY_BOUND:
4023 // calculate lub(A[], B[])
4024 Type[] elements = new Type[ts.length];
4025 for (int i = 0 ; i < ts.length ; i++) {
4026 Type elem = elements[i] = elemTypeFun.apply(ts[i]);
4027 if (elem.isPrimitive()) {
4028 // if a primitive type is found, then return
4029 // arraySuperType unless all the types are the
4030 // same
4031 Type first = ts[0];
4032 for (int j = 1 ; j < ts.length ; j++) {
4033 if (!isSameType(first, ts[j])) {
4034 // lub(int[], B[]) is Cloneable & Serializable
4035 return arraySuperType();
4036 }
4037 }
4038 // all the array types are the same, return one
4039 // lub(int[], int[]) is int[]
4040 return first;
4041 }
4042 }
4043 // lub(A[], B[]) is lub(A, B)[]
4044 return new ArrayType(lub(elements), syms.arrayClass);
4045
4046 case CLASS_BOUND:
4047 // calculate lub(A, B)
4048 int startIdx = 0;
4049 for (int i = 0; i < ts.length ; i++) {
4050 Type t = ts[i];
4051 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) {
4052 break;
4053 } else {
4054 startIdx++;
4055 }
4056 }
4057 Assert.check(startIdx < ts.length);
4058 //step 1 - compute erased candidate set (EC)
4059 List<Type> cl = erasedSupertypes(ts[startIdx]);
4060 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4061 Type t = ts[i];
4062 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
4063 cl = intersect(cl, erasedSupertypes(t));
4064 }
4065 //step 2 - compute minimal erased candidate set (MEC)
4066 List<Type> mec = closureMin(cl);
4067 //step 3 - for each element G in MEC, compute lci(Inv(G))
4068 List<Type> candidates = List.nil();
4069 for (Type erasedSupertype : mec) {
4070 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
4071 for (int i = startIdx + 1 ; i < ts.length ; i++) {
4072 Type superType = asSuper(ts[i], erasedSupertype.tsym);
4073 lci = intersect(lci, superType != null ? List.of(superType) : List.nil());
4074 }
4075 candidates = candidates.appendList(lci);
4076 }
4077 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
4078 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
4079 return compoundMin(candidates);
4080
4081 default:
4082 // calculate lub(A, B[])
4083 List<Type> classes = List.of(arraySuperType());
4084 for (int i = 0 ; i < ts.length ; i++) {
4085 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays
4086 classes = classes.prepend(ts[i]);
4087 }
4088 // lub(A, B[]) is lub(A, arraySuperType)
4089 return lub(classes);
4090 }
4091 }
4092 // where
4093 List<Type> erasedSupertypes(Type t) {
4094 ListBuffer<Type> buf = new ListBuffer<>();
4095 for (Type sup : closure(t)) {
4096 if (sup.hasTag(TYPEVAR)) {
4097 buf.append(sup);
4098 } else {
4099 buf.append(erasure(sup));
4100 }
4101 }
4102 return buf.toList();
4103 }
4104
4105 private Type arraySuperType;
4106 private Type arraySuperType() {
4107 // initialized lazily to avoid problems during compiler startup
4108 if (arraySuperType == null) {
4109 // JLS 10.8: all arrays implement Cloneable and Serializable.
4110 arraySuperType = makeIntersectionType(List.of(syms.serializableType,
4111 syms.cloneableType), true);
4112 }
4113 return arraySuperType;
4114 }
4115 // </editor-fold>
4116
4117 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
4118 public Type glb(List<Type> ts) {
4119 Type t1 = ts.head;
4120 for (Type t2 : ts.tail) {
4121 if (t1.isErroneous())
4122 return t1;
4123 t1 = glb(t1, t2);
4124 }
4125 return t1;
4126 }
4127 //where
4128 public Type glb(Type t, Type s) {
4129 if (s == null)
4130 return t;
4131 else if (t.isPrimitive() || s.isPrimitive())
4132 return syms.errType;
4133 else if (isSubtypeNoCapture(t, s))
4134 return t;
4135 else if (isSubtypeNoCapture(s, t))
4136 return s;
4137
4138 List<Type> closure = union(closure(t), closure(s));
4139 return glbFlattened(closure, t);
4140 }
4141 //where
4142 /**
4143 * Perform glb for a list of non-primitive, non-error, non-compound types;
4144 * redundant elements are removed. Bounds should be ordered according to
4145 * {@link Symbol#precedes(TypeSymbol,Types)}.
4146 *
4147 * @param flatBounds List of type to glb
4148 * @param errT Original type to use if the result is an error type
4149 */
4150 private Type glbFlattened(List<Type> flatBounds, Type errT) {
4151 List<Type> bounds = closureMin(flatBounds);
4152
4153 if (bounds.isEmpty()) { // length == 0
4154 return syms.objectType;
4155 } else if (bounds.tail.isEmpty()) { // length == 1
4156 return bounds.head;
4157 } else { // length > 1
4158 int classCount = 0;
4159 List<Type> cvars = List.nil();
4160 List<Type> lowers = List.nil();
4161 for (Type bound : bounds) {
4162 if (!bound.isInterface()) {
4163 classCount++;
4164 Type lower = cvarLowerBound(bound);
4165 if (bound != lower && !lower.hasTag(BOT)) {
4166 cvars = cvars.append(bound);
4167 lowers = lowers.append(lower);
4168 }
4169 }
4170 }
4171 if (classCount > 1) {
4172 if (lowers.isEmpty()) {
4173 return createErrorType(errT);
4174 } else {
4175 // try again with lower bounds included instead of capture variables
4176 List<Type> newBounds = bounds.diff(cvars).appendList(lowers);
4177 return glb(newBounds);
4178 }
4179 }
4180 }
4181 return makeIntersectionType(bounds);
4182 }
4183 // </editor-fold>
4184
4185 // <editor-fold defaultstate="collapsed" desc="hashCode">
4186 /**
4187 * Compute a hash code on a type.
4188 */
4189 public int hashCode(Type t) {
4190 return hashCode(t, false);
4191 }
4192
4193 public int hashCode(Type t, boolean strict) {
4194 return strict ?
4195 hashCodeStrictVisitor.visit(t) :
4196 hashCodeVisitor.visit(t);
4197 }
4198 // where
4199 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor();
4200 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() {
4201 @Override
4202 public Integer visitTypeVar(TypeVar t, Void ignored) {
4203 return System.identityHashCode(t);
4204 }
4205 };
4206
4207 private static class HashCodeVisitor extends UnaryVisitor<Integer> {
4208 public Integer visitType(Type t, Void ignored) {
4209 return t.getTag().ordinal();
4210 }
4211
4212 @Override
4213 public Integer visitClassType(ClassType t, Void ignored) {
4214 int result = visit(t.getEnclosingType());
4215 result *= 127;
4216 result += t.tsym.flatName().hashCode();
4217 for (Type s : t.getTypeArguments()) {
4218 result *= 127;
4219 result += visit(s);
4220 }
4221 return result;
4222 }
4223
4224 @Override
4225 public Integer visitMethodType(MethodType t, Void ignored) {
4226 int h = METHOD.ordinal();
4227 for (List<Type> thisargs = t.argtypes;
4228 thisargs.tail != null;
4229 thisargs = thisargs.tail)
4230 h = (h << 5) + visit(thisargs.head);
4231 return (h << 5) + visit(t.restype);
4232 }
4233
4234 @Override
4235 public Integer visitWildcardType(WildcardType t, Void ignored) {
4236 int result = t.kind.hashCode();
4237 if (t.type != null) {
4238 result *= 127;
4239 result += visit(t.type);
4240 }
4241 return result;
4242 }
4243
4244 @Override
4245 public Integer visitArrayType(ArrayType t, Void ignored) {
4246 return visit(t.elemtype) + 12;
4247 }
4248
4249 @Override
4250 public Integer visitTypeVar(TypeVar t, Void ignored) {
4251 return System.identityHashCode(t);
4252 }
4253
4254 @Override
4255 public Integer visitUndetVar(UndetVar t, Void ignored) {
4256 return System.identityHashCode(t);
4257 }
4258
4259 @Override
4260 public Integer visitErrorType(ErrorType t, Void ignored) {
4261 return 0;
4262 }
4263 }
4264 // </editor-fold>
4265
4266 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
4267 /**
4268 * Does t have a result that is a subtype of the result type of s,
4269 * suitable for covariant returns? It is assumed that both types
4270 * are (possibly polymorphic) method types. Monomorphic method
4271 * types are handled in the obvious way. Polymorphic method types
4272 * require renaming all type variables of one to corresponding
4273 * type variables in the other, where correspondence is by
4274 * position in the type parameter list. */
4275 public boolean resultSubtype(Type t, Type s, Warner warner) {
4276 List<Type> tvars = t.getTypeArguments();
4277 List<Type> svars = s.getTypeArguments();
4278 Type tres = t.getReturnType();
4279 Type sres = subst(s.getReturnType(), svars, tvars);
4280 return covariantReturnType(tres, sres, warner);
4281 }
4282
4283 /**
4284 * Return-Type-Substitutable.
4285 * @jls 8.4.5 Method Result
4286 */
4287 public boolean returnTypeSubstitutable(Type r1, Type r2) {
4288 if (hasSameArgs(r1, r2))
4289 return resultSubtype(r1, r2, noWarnings);
4290 else
4291 return covariantReturnType(r1.getReturnType(),
4292 erasure(r2.getReturnType()),
4293 noWarnings);
4294 }
4295
4296 public boolean returnTypeSubstitutable(Type r1,
4297 Type r2, Type r2res,
4298 Warner warner) {
4299 if (isSameType(r1.getReturnType(), r2res))
4300 return true;
4301 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
4302 return false;
4303
4304 if (hasSameArgs(r1, r2))
4305 return covariantReturnType(r1.getReturnType(), r2res, warner);
4306 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
4307 return true;
4308 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
4309 return false;
4310 warner.warn(LintCategory.UNCHECKED);
4311 return true;
4312 }
4313
4314 /**
4315 * Is t an appropriate return type in an overrider for a
4316 * method that returns s?
4317 */
4318 public boolean covariantReturnType(Type t, Type s, Warner warner) {
4319 return
4320 isSameType(t, s) ||
4321 !t.isPrimitive() &&
4322 !s.isPrimitive() &&
4323 isAssignable(t, s, warner);
4324 }
4325 // </editor-fold>
4326
4327 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
4328 /**
4329 * Return the class that boxes the given primitive.
4330 */
4331 public ClassSymbol boxedClass(Type t) {
4332 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]);
4333 }
4334
4335 /**
4336 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
4337 */
4338 public Type boxedTypeOrType(Type t) {
4339 return t.isPrimitive() ?
4340 boxedClass(t).type :
4341 t;
4342 }
4343
4344 /**
4345 * Return the primitive type corresponding to a boxed type.
4346 */
4347 public Type unboxedType(Type t) {
4348 if (t.hasTag(ERROR))
4349 return Type.noType;
4350 for (int i=0; i<syms.boxedName.length; i++) {
4351 Name box = syms.boxedName[i];
4352 if (box != null &&
4353 asSuper(t, syms.enterClass(syms.java_base, box)) != null)
4354 return syms.typeOfTag[i];
4355 }
4356 return Type.noType;
4357 }
4358
4359 /**
4360 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
4361 */
4362 public Type unboxedTypeOrType(Type t) {
4363 Type unboxedType = unboxedType(t);
4364 return unboxedType.hasTag(NONE) ? t : unboxedType;
4365 }
4366 // </editor-fold>
4367
4368 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
4369 /*
4370 * JLS 5.1.10 Capture Conversion:
4371 *
4372 * Let G name a generic type declaration with n formal type
4373 * parameters A1 ... An with corresponding bounds U1 ... Un. There
4374 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
4375 * where, for 1 <= i <= n:
4376 *
4377 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
4378 * Si is a fresh type variable whose upper bound is
4379 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
4380 * type.
4381 *
4382 * + If Ti is a wildcard type argument of the form ? extends Bi,
4383 * then Si is a fresh type variable whose upper bound is
4384 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
4385 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
4386 * a compile-time error if for any two classes (not interfaces)
4387 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
4388 *
4389 * + If Ti is a wildcard type argument of the form ? super Bi,
4390 * then Si is a fresh type variable whose upper bound is
4391 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
4392 *
4393 * + Otherwise, Si = Ti.
4394 *
4395 * Capture conversion on any type other than a parameterized type
4396 * (4.5) acts as an identity conversion (5.1.1). Capture
4397 * conversions never require a special action at run time and
4398 * therefore never throw an exception at run time.
4399 *
4400 * Capture conversion is not applied recursively.
4401 */
4402 /**
4403 * Capture conversion as specified by the JLS.
4404 */
4405
4406 public List<Type> capture(List<Type> ts) {
4407 List<Type> buf = List.nil();
4408 for (Type t : ts) {
4409 buf = buf.prepend(capture(t));
4410 }
4411 return buf.reverse();
4412 }
4413
4414 public Type capture(Type t) {
4415 if (!t.hasTag(CLASS)) {
4416 return t;
4417 }
4418 if (t.getEnclosingType() != Type.noType) {
4419 Type capturedEncl = capture(t.getEnclosingType());
4420 if (capturedEncl != t.getEnclosingType()) {
4421 Type type1 = memberType(capturedEncl, t.tsym);
4422 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
4423 }
4424 }
4425 ClassType cls = (ClassType)t;
4426 if (cls.isRaw() || !cls.isParameterized())
4427 return cls;
4428
4429 ClassType G = (ClassType)cls.asElement().asType();
4430 List<Type> A = G.getTypeArguments();
4431 List<Type> T = cls.getTypeArguments();
4432 List<Type> S = freshTypeVariables(T);
4433
4434 List<Type> currentA = A;
4435 List<Type> currentT = T;
4436 List<Type> currentS = S;
4437 boolean captured = false;
4438 while (!currentA.isEmpty() &&
4439 !currentT.isEmpty() &&
4440 !currentS.isEmpty()) {
4441 if (currentS.head != currentT.head) {
4442 captured = true;
4443 WildcardType Ti = (WildcardType)currentT.head;
4444 Type Ui = currentA.head.getUpperBound();
4445 CapturedType Si = (CapturedType)currentS.head;
4446 if (Ui == null)
4447 Ui = syms.objectType;
4448 switch (Ti.kind) {
4449 case UNBOUND:
4450 Si.setUpperBound( subst(Ui, A, S) );
4451 Si.lower = syms.botType;
4452 break;
4453 case EXTENDS:
4454 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) );
4455 Si.lower = syms.botType;
4456 break;
4457 case SUPER:
4458 Si.setUpperBound( subst(Ui, A, S) );
4459 Si.lower = Ti.getSuperBound();
4460 break;
4461 }
4462 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound();
4463 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower;
4464 if (!Si.getUpperBound().hasTag(ERROR) &&
4465 !Si.lower.hasTag(ERROR) &&
4466 isSameType(tmpBound, tmpLower)) {
4467 currentS.head = Si.getUpperBound();
4468 }
4469 }
4470 currentA = currentA.tail;
4471 currentT = currentT.tail;
4472 currentS = currentS.tail;
4473 }
4474 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
4475 return erasure(t); // some "rare" type involved
4476
4477 if (captured)
4478 return new ClassType(cls.getEnclosingType(), S, cls.tsym,
4479 cls.getMetadata());
4480 else
4481 return t;
4482 }
4483 // where
4484 public List<Type> freshTypeVariables(List<Type> types) {
4485 ListBuffer<Type> result = new ListBuffer<>();
4486 for (Type t : types) {
4487 if (t.hasTag(WILDCARD)) {
4488 Type bound = ((WildcardType)t).getExtendsBound();
4489 if (bound == null)
4490 bound = syms.objectType;
4491 result.append(new CapturedType(capturedName,
4492 syms.noSymbol,
4493 bound,
4494 syms.botType,
4495 (WildcardType)t));
4496 } else {
4497 result.append(t);
4498 }
4499 }
4500 return result.toList();
4501 }
4502 // </editor-fold>
4503
4504 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
4505 private boolean sideCast(Type from, Type to, Warner warn) {
4506 // We are casting from type $from$ to type $to$, which are
4507 // non-final unrelated types. This method
4508 // tries to reject a cast by transferring type parameters
4509 // from $to$ to $from$ by common superinterfaces.
4510 boolean reverse = false;
4511 Type target = to;
4512 if ((to.tsym.flags() & INTERFACE) == 0) {
4513 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4514 reverse = true;
4515 to = from;
4516 from = target;
4517 }
4518 List<Type> commonSupers = superClosure(to, erasure(from));
4519 boolean giveWarning = commonSupers.isEmpty();
4520 // The arguments to the supers could be unified here to
4521 // get a more accurate analysis
4522 while (commonSupers.nonEmpty()) {
4523 Type t1 = asSuper(from, commonSupers.head.tsym);
4524 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
4525 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4526 return false;
4527 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
4528 commonSupers = commonSupers.tail;
4529 }
4530 if (giveWarning && !isReifiable(reverse ? from : to))
4531 warn.warn(LintCategory.UNCHECKED);
4532 return true;
4533 }
4534
4535 private boolean sideCastFinal(Type from, Type to, Warner warn) {
4536 // We are casting from type $from$ to type $to$, which are
4537 // unrelated types one of which is final and the other of
4538 // which is an interface. This method
4539 // tries to reject a cast by transferring type parameters
4540 // from the final class to the interface.
4541 boolean reverse = false;
4542 Type target = to;
4543 if ((to.tsym.flags() & INTERFACE) == 0) {
4544 Assert.check((from.tsym.flags() & INTERFACE) != 0);
4545 reverse = true;
4546 to = from;
4547 from = target;
4548 }
4549 Assert.check((from.tsym.flags() & FINAL) != 0);
4550 Type t1 = asSuper(from, to.tsym);
4551 if (t1 == null) return false;
4552 Type t2 = to;
4553 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
4554 return false;
4555 if (!isReifiable(target) &&
4556 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
4557 warn.warn(LintCategory.UNCHECKED);
4558 return true;
4559 }
4560
4561 private boolean giveWarning(Type from, Type to) {
4562 List<Type> bounds = to.isCompound() ?
4563 directSupertypes(to) : List.of(to);
4564 for (Type b : bounds) {
4565 Type subFrom = asSub(from, b.tsym);
4566 if (b.isParameterized() &&
4567 (!(isUnbounded(b) ||
4568 isSubtype(from, b) ||
4569 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
4570 return true;
4571 }
4572 }
4573 return false;
4574 }
4575
4576 private List<Type> superClosure(Type t, Type s) {
4577 List<Type> cl = List.nil();
4578 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
4579 if (isSubtype(s, erasure(l.head))) {
4580 cl = insert(cl, l.head);
4581 } else {
4582 cl = union(cl, superClosure(l.head, s));
4583 }
4584 }
4585 return cl;
4586 }
4587
4588 private boolean containsTypeEquivalent(Type t, Type s) {
4589 return isSameType(t, s) || // shortcut
4590 containsType(t, s) && containsType(s, t);
4591 }
4592
4593 // <editor-fold defaultstate="collapsed" desc="adapt">
4594 /**
4595 * Adapt a type by computing a substitution which maps a source
4596 * type to a target type.
4597 *
4598 * @param source the source type
4599 * @param target the target type
4600 * @param from the type variables of the computed substitution
4601 * @param to the types of the computed substitution.
4602 */
4603 public void adapt(Type source,
4604 Type target,
4605 ListBuffer<Type> from,
4606 ListBuffer<Type> to) throws AdaptFailure {
4607 new Adapter(from, to).adapt(source, target);
4608 }
4609
4610 class Adapter extends SimpleVisitor<Void, Type> {
4611
4612 ListBuffer<Type> from;
4613 ListBuffer<Type> to;
4614 Map<Symbol,Type> mapping;
4615
4616 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
4617 this.from = from;
4618 this.to = to;
4619 mapping = new HashMap<>();
4620 }
4621
4622 public void adapt(Type source, Type target) throws AdaptFailure {
4623 visit(source, target);
4624 List<Type> fromList = from.toList();
4625 List<Type> toList = to.toList();
4626 while (!fromList.isEmpty()) {
4627 Type val = mapping.get(fromList.head.tsym);
4628 if (toList.head != val)
4629 toList.head = val;
4630 fromList = fromList.tail;
4631 toList = toList.tail;
4632 }
4633 }
4634
4635 @Override
4636 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
4637 if (target.hasTag(CLASS))
4638 adaptRecursive(source.allparams(), target.allparams());
4639 return null;
4640 }
4641
4642 @Override
4643 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
4644 if (target.hasTag(ARRAY))
4645 adaptRecursive(elemtype(source), elemtype(target));
4646 return null;
4647 }
4648
4649 @Override
4650 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
4651 if (source.isExtendsBound())
4652 adaptRecursive(wildUpperBound(source), wildUpperBound(target));
4653 else if (source.isSuperBound())
4654 adaptRecursive(wildLowerBound(source), wildLowerBound(target));
4655 return null;
4656 }
4657
4658 @Override
4659 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
4660 // Check to see if there is
4661 // already a mapping for $source$, in which case
4662 // the old mapping will be merged with the new
4663 Type val = mapping.get(source.tsym);
4664 if (val != null) {
4665 if (val.isSuperBound() && target.isSuperBound()) {
4666 val = isSubtype(wildLowerBound(val), wildLowerBound(target))
4667 ? target : val;
4668 } else if (val.isExtendsBound() && target.isExtendsBound()) {
4669 val = isSubtype(wildUpperBound(val), wildUpperBound(target))
4670 ? val : target;
4671 } else if (!isSameType(val, target)) {
4672 throw new AdaptFailure();
4673 }
4674 } else {
4675 val = target;
4676 from.append(source);
4677 to.append(target);
4678 }
4679 mapping.put(source.tsym, val);
4680 return null;
4681 }
4682
4683 @Override
4684 public Void visitType(Type source, Type target) {
4685 return null;
4686 }
4687
4688 private Set<TypePair> cache = new HashSet<>();
4689
4690 private void adaptRecursive(Type source, Type target) {
4691 TypePair pair = new TypePair(source, target);
4692 if (cache.add(pair)) {
4693 try {
4694 visit(source, target);
4695 } finally {
4696 cache.remove(pair);
4697 }
4698 }
4699 }
4700
4701 private void adaptRecursive(List<Type> source, List<Type> target) {
4702 if (source.length() == target.length()) {
4703 while (source.nonEmpty()) {
4704 adaptRecursive(source.head, target.head);
4705 source = source.tail;
4706 target = target.tail;
4707 }
4708 }
4709 }
4710 }
4711
4712 public static class AdaptFailure extends RuntimeException {
4713 static final long serialVersionUID = -7490231548272701566L;
4714 }
4715
4716 private void adaptSelf(Type t,
4717 ListBuffer<Type> from,
4718 ListBuffer<Type> to) {
4719 try {
4720 //if (t.tsym.type != t)
4721 adapt(t.tsym.type, t, from, to);
4722 } catch (AdaptFailure ex) {
4723 // Adapt should never fail calculating a mapping from
4724 // t.tsym.type to t as there can be no merge problem.
4725 throw new AssertionError(ex);
4726 }
4727 }
4728 // </editor-fold>
4729
4730 /**
4731 * Rewrite all type variables (universal quantifiers) in the given
4732 * type to wildcards (existential quantifiers). This is used to
4733 * determine if a cast is allowed. For example, if high is true
4734 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4735 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4736 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4737 * List<Integer>} with a warning.
4738 * @param t a type
4739 * @param high if true return an upper bound; otherwise a lower
4740 * bound
4741 * @param rewriteTypeVars only rewrite captured wildcards if false;
4742 * otherwise rewrite all type variables
4743 * @return the type rewritten with wildcards (existential
4744 * quantifiers) only
4745 */
4746 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4747 return new Rewriter(high, rewriteTypeVars).visit(t);
4748 }
4749
4750 class Rewriter extends UnaryVisitor<Type> {
4751
4752 boolean high;
4753 boolean rewriteTypeVars;
4754 // map to avoid visiting same type argument twice, like in Foo<T>.Bar<T>
4755 Map<Type, Type> argMap = new HashMap<>();
4756 // cycle detection within an argument, see JDK-8324809
4757 Set<Type> seen = new HashSet<>();
4758
4759 Rewriter(boolean high, boolean rewriteTypeVars) {
4760 this.high = high;
4761 this.rewriteTypeVars = rewriteTypeVars;
4762 }
4763
4764 @Override
4765 public Type visitClassType(ClassType t, Void s) {
4766 ListBuffer<Type> rewritten = new ListBuffer<>();
4767 boolean changed = false;
4768 for (Type arg : t.allparams()) {
4769 Type bound = argMap.get(arg);
4770 if (bound == null) {
4771 argMap.put(arg, bound = visit(arg));
4772 }
4773 if (arg != bound) {
4774 changed = true;
4775 }
4776 rewritten.append(bound);
4777 }
4778 if (changed)
4779 return subst(t.tsym.type,
4780 t.tsym.type.allparams(),
4781 rewritten.toList());
4782 else
4783 return t;
4784 }
4785
4786 public Type visitType(Type t, Void s) {
4787 return t;
4788 }
4789
4790 @Override
4791 public Type visitCapturedType(CapturedType t, Void s) {
4792 Type w_bound = t.wildcard.type;
4793 Type bound = w_bound.contains(t) ?
4794 erasure(w_bound) :
4795 visit(w_bound);
4796 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4797 }
4798
4799 @Override
4800 public Type visitTypeVar(TypeVar t, Void s) {
4801 if (seen.add(t)) {
4802 if (rewriteTypeVars) {
4803 Type bound = t.getUpperBound().contains(t) ?
4804 erasure(t.getUpperBound()) :
4805 visit(t.getUpperBound());
4806 return rewriteAsWildcardType(bound, t, EXTENDS);
4807 } else {
4808 return t;
4809 }
4810 } else {
4811 return rewriteTypeVars ? makeExtendsWildcard(syms.objectType, t) : t;
4812 }
4813 }
4814
4815 @Override
4816 public Type visitWildcardType(WildcardType t, Void s) {
4817 Type bound2 = visit(t.type);
4818 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4819 }
4820
4821 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4822 switch (bk) {
4823 case EXTENDS: return high ?
4824 makeExtendsWildcard(B(bound), formal) :
4825 makeExtendsWildcard(syms.objectType, formal);
4826 case SUPER: return high ?
4827 makeSuperWildcard(syms.botType, formal) :
4828 makeSuperWildcard(B(bound), formal);
4829 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4830 default:
4831 Assert.error("Invalid bound kind " + bk);
4832 return null;
4833 }
4834 }
4835
4836 Type B(Type t) {
4837 while (t.hasTag(WILDCARD)) {
4838 WildcardType w = (WildcardType)t;
4839 t = high ?
4840 w.getExtendsBound() :
4841 w.getSuperBound();
4842 if (t == null) {
4843 t = high ? syms.objectType : syms.botType;
4844 }
4845 }
4846 return t;
4847 }
4848 }
4849
4850
4851 /**
4852 * Create a wildcard with the given upper (extends) bound; create
4853 * an unbounded wildcard if bound is Object.
4854 *
4855 * @param bound the upper bound
4856 * @param formal the formal type parameter that will be
4857 * substituted by the wildcard
4858 */
4859 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4860 if (bound == syms.objectType) {
4861 return new WildcardType(syms.objectType,
4862 BoundKind.UNBOUND,
4863 syms.boundClass,
4864 formal);
4865 } else {
4866 return new WildcardType(bound,
4867 BoundKind.EXTENDS,
4868 syms.boundClass,
4869 formal);
4870 }
4871 }
4872
4873 /**
4874 * Create a wildcard with the given lower (super) bound; create an
4875 * unbounded wildcard if bound is bottom (type of {@code null}).
4876 *
4877 * @param bound the lower bound
4878 * @param formal the formal type parameter that will be
4879 * substituted by the wildcard
4880 */
4881 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4882 if (bound.hasTag(BOT)) {
4883 return new WildcardType(syms.objectType,
4884 BoundKind.UNBOUND,
4885 syms.boundClass,
4886 formal);
4887 } else {
4888 return new WildcardType(bound,
4889 BoundKind.SUPER,
4890 syms.boundClass,
4891 formal);
4892 }
4893 }
4894
4895 /**
4896 * A wrapper for a type that allows use in sets.
4897 */
4898 public static class UniqueType {
4899 public final Type type;
4900 final Types types;
4901 private boolean encodeTypeSig;
4902
4903 public UniqueType(Type type, Types types, boolean encodeTypeSig) {
4904 this.type = type;
4905 this.types = types;
4906 this.encodeTypeSig = encodeTypeSig;
4907 }
4908
4909 public UniqueType(Type type, Types types) {
4910 this(type, types, true);
4911 }
4912
4913 public int hashCode() {
4914 return types.hashCode(type);
4915 }
4916
4917 public boolean equals(Object obj) {
4918 return (obj instanceof UniqueType uniqueType) &&
4919 types.isSameType(type, uniqueType.type);
4920 }
4921
4922 public boolean encodeTypeSig() {
4923 return encodeTypeSig;
4924 }
4925
4926 public String toString() {
4927 return type.toString();
4928 }
4929
4930 }
4931 // </editor-fold>
4932
4933 // <editor-fold defaultstate="collapsed" desc="Visitors">
4934 /**
4935 * A default visitor for types. All visitor methods except
4936 * visitType are implemented by delegating to visitType. Concrete
4937 * subclasses must provide an implementation of visitType and can
4938 * override other methods as needed.
4939 *
4940 * @param <R> the return type of the operation implemented by this
4941 * visitor; use Void if no return type is needed.
4942 * @param <S> the type of the second argument (the first being the
4943 * type itself) of the operation implemented by this visitor; use
4944 * Void if a second argument is not needed.
4945 */
4946 public abstract static class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4947 public final R visit(Type t, S s) { return t.accept(this, s); }
4948 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4949 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4950 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4951 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4952 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4953 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); }
4954 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4955 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4956 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4957 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4958 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4959 }
4960
4961 /**
4962 * A default visitor for symbols. All visitor methods except
4963 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4964 * subclasses must provide an implementation of visitSymbol and can
4965 * override other methods as needed.
4966 *
4967 * @param <R> the return type of the operation implemented by this
4968 * visitor; use Void if no return type is needed.
4969 * @param <S> the type of the second argument (the first being the
4970 * symbol itself) of the operation implemented by this visitor; use
4971 * Void if a second argument is not needed.
4972 */
4973 public abstract static class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4974 public final R visit(Symbol s, S arg) { return s.accept(this, arg); }
4975 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4976 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4977 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4978 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4979 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4980 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4981 }
4982
4983 /**
4984 * A <em>simple</em> visitor for types. This visitor is simple as
4985 * captured wildcards, for-all types (generic methods), and
4986 * undetermined type variables (part of inference) are hidden.
4987 * Captured wildcards are hidden by treating them as type
4988 * variables and the rest are hidden by visiting their qtypes.
4989 *
4990 * @param <R> the return type of the operation implemented by this
4991 * visitor; use Void if no return type is needed.
4992 * @param <S> the type of the second argument (the first being the
4993 * type itself) of the operation implemented by this visitor; use
4994 * Void if a second argument is not needed.
4995 */
4996 public abstract static class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4997 @Override
4998 public R visitCapturedType(CapturedType t, S s) {
4999 return visitTypeVar(t, s);
5000 }
5001 @Override
5002 public R visitForAll(ForAll t, S s) {
5003 return visit(t.qtype, s);
5004 }
5005 @Override
5006 public R visitUndetVar(UndetVar t, S s) {
5007 return visit(t.qtype, s);
5008 }
5009 }
5010
5011 /**
5012 * A plain relation on types. That is a 2-ary function on the
5013 * form Type × Type → Boolean.
5014 * <!-- In plain text: Type x Type -> Boolean -->
5015 */
5016 public abstract static class TypeRelation extends SimpleVisitor<Boolean,Type> {}
5017
5018 /**
5019 * A convenience visitor for implementing operations that only
5020 * require one argument (the type itself), that is, unary
5021 * operations.
5022 *
5023 * @param <R> the return type of the operation implemented by this
5024 * visitor; use Void if no return type is needed.
5025 */
5026 public abstract static class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
5027 public final R visit(Type t) { return t.accept(this, null); }
5028 }
5029
5030 /**
5031 * A visitor for implementing a mapping from types to types. The
5032 * default behavior of this class is to implement the identity
5033 * mapping (mapping a type to itself). This can be overridden in
5034 * subclasses.
5035 *
5036 * @param <S> the type of the second argument (the first being the
5037 * type itself) of this mapping; use Void if a second argument is
5038 * not needed.
5039 */
5040 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
5041 public final Type visit(Type t) { return t.accept(this, null); }
5042 public Type visitType(Type t, S s) { return t; }
5043 }
5044
5045 /**
5046 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}.
5047 * This class implements the functional interface {@code Function}, that allows it to be used
5048 * fluently in stream-like processing.
5049 */
5050 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> {
5051 @Override
5052 public Type apply(Type type) { return visit(type); }
5053
5054 List<Type> visit(List<Type> ts, S s) {
5055 return ts.map(t -> visit(t, s));
5056 }
5057
5058 @Override
5059 public Type visitCapturedType(CapturedType t, S s) {
5060 return visitTypeVar(t, s);
5061 }
5062 }
5063 // </editor-fold>
5064
5065 // <editor-fold defaultstate="collapsed" desc="Unconditionality">
5066 /** Check unconditionality between any combination of reference or primitive types.
5067 *
5068 * Rules:
5069 * an identity conversion
5070 * a widening reference conversion
5071 * a widening primitive conversion (delegates to `checkUnconditionallyExactPrimitives`)
5072 * a boxing conversion
5073 * a boxing conversion followed by a widening reference conversion
5074 *
5075 * @param source Source primitive or reference type
5076 * @param target Target primitive or reference type
5077 */
5078 public boolean isUnconditionallyExact(Type source, Type target) {
5079 if (isSameType(source, target)) {
5080 return true;
5081 }
5082
5083 return target.isPrimitive()
5084 ? isUnconditionallyExactPrimitives(source, target)
5085 : isSubtype(boxedTypeOrType(erasure(source)), target);
5086 }
5087
5088 /** Check unconditionality between primitive types.
5089 *
5090 * - widening from one integral type to another,
5091 * - widening from one floating point type to another,
5092 * - widening from byte, short, or char to a floating point type,
5093 * - widening from int to double.
5094 *
5095 * @param selectorType Type of selector
5096 * @param targetType Target type
5097 */
5098 public boolean isUnconditionallyExactPrimitives(Type selectorType, Type targetType) {
5099 if (isSameType(selectorType, targetType)) {
5100 return true;
5101 }
5102
5103 return (selectorType.isPrimitive() && targetType.isPrimitive()) &&
5104 ((selectorType.hasTag(BYTE) && !targetType.hasTag(CHAR)) ||
5105 (selectorType.hasTag(SHORT) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag()))) ||
5106 (selectorType.hasTag(CHAR) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag()))) ||
5107 (selectorType.hasTag(INT) && (targetType.hasTag(DOUBLE) || targetType.hasTag(LONG))) ||
5108 (selectorType.hasTag(FLOAT) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag()))));
5109 }
5110 // </editor-fold>
5111
5112 // <editor-fold defaultstate="collapsed" desc="Annotation support">
5113
5114 public RetentionPolicy getRetention(Attribute.Compound a) {
5115 return getRetention(a.type.tsym);
5116 }
5117
5118 public RetentionPolicy getRetention(TypeSymbol sym) {
5119 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
5120 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
5121 if (c != null) {
5122 Attribute value = c.member(names.value);
5123 if (value != null && value instanceof Attribute.Enum attributeEnum) {
5124 Name levelName = attributeEnum.value.name;
5125 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
5126 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
5127 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
5128 else ;// /* fail soft */ throw new AssertionError(levelName);
5129 }
5130 }
5131 return vis;
5132 }
5133 // </editor-fold>
5134
5135 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
5136
5137 public abstract class SignatureGenerator {
5138
5139 public class InvalidSignatureException extends CompilerInternalException {
5140 private static final long serialVersionUID = 0;
5141
5142 private final transient Type type;
5143
5144 InvalidSignatureException(Type type, boolean dumpStackTraceOnError) {
5145 super(dumpStackTraceOnError);
5146 this.type = type;
5147 }
5148
5149 public Type type() {
5150 return type;
5151 }
5152 }
5153
5154 protected abstract void append(char ch);
5155 protected abstract void append(byte[] ba);
5156 protected abstract void append(Name name);
5157 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
5158
5159 protected void reportIllegalSignature(Type t) {
5160 throw new InvalidSignatureException(t, Types.this.dumpStacktraceOnError);
5161 }
5162
5163 /**
5164 * Assemble signature of given type in string buffer.
5165 */
5166 public void assembleSig(Type type) {
5167 switch (type.getTag()) {
5168 case BYTE:
5169 append('B');
5170 break;
5171 case SHORT:
5172 append('S');
5173 break;
5174 case CHAR:
5175 append('C');
5176 break;
5177 case INT:
5178 append('I');
5179 break;
5180 case LONG:
5181 append('J');
5182 break;
5183 case FLOAT:
5184 append('F');
5185 break;
5186 case DOUBLE:
5187 append('D');
5188 break;
5189 case BOOLEAN:
5190 append('Z');
5191 break;
5192 case VOID:
5193 append('V');
5194 break;
5195 case CLASS:
5196 if (type.isCompound()) {
5197 reportIllegalSignature(type);
5198 }
5199 append('L');
5200 assembleClassSig(type);
5201 append(';');
5202 break;
5203 case ARRAY:
5204 ArrayType at = (ArrayType) type;
5205 append('[');
5206 assembleSig(at.elemtype);
5207 break;
5208 case METHOD:
5209 MethodType mt = (MethodType) type;
5210 append('(');
5211 assembleSig(mt.argtypes);
5212 append(')');
5213 assembleSig(mt.restype);
5214 if (hasTypeVar(mt.thrown)) {
5215 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
5216 append('^');
5217 assembleSig(l.head);
5218 }
5219 }
5220 break;
5221 case WILDCARD: {
5222 Type.WildcardType ta = (Type.WildcardType) type;
5223 switch (ta.kind) {
5224 case SUPER:
5225 append('-');
5226 assembleSig(ta.type);
5227 break;
5228 case EXTENDS:
5229 append('+');
5230 assembleSig(ta.type);
5231 break;
5232 case UNBOUND:
5233 append('*');
5234 break;
5235 default:
5236 throw new AssertionError(ta.kind);
5237 }
5238 break;
5239 }
5240 case TYPEVAR:
5241 if (((TypeVar)type).isCaptured()) {
5242 reportIllegalSignature(type);
5243 }
5244 append('T');
5245 append(type.tsym.name);
5246 append(';');
5247 break;
5248 case FORALL:
5249 Type.ForAll ft = (Type.ForAll) type;
5250 assembleParamsSig(ft.tvars);
5251 assembleSig(ft.qtype);
5252 break;
5253 default:
5254 throw new AssertionError("typeSig " + type.getTag());
5255 }
5256 }
5257
5258 public boolean hasTypeVar(List<Type> l) {
5259 while (l.nonEmpty()) {
5260 if (l.head.hasTag(TypeTag.TYPEVAR)) {
5261 return true;
5262 }
5263 l = l.tail;
5264 }
5265 return false;
5266 }
5267
5268 public void assembleClassSig(Type type) {
5269 ClassType ct = (ClassType) type;
5270 ClassSymbol c = (ClassSymbol) ct.tsym;
5271 classReference(c);
5272 Type outer = ct.getEnclosingType();
5273 if (outer.allparams().nonEmpty()) {
5274 boolean rawOuter =
5275 c.owner.kind == MTH || // either a local class
5276 c.name == Types.this.names.empty; // or anonymous
5277 assembleClassSig(rawOuter
5278 ? Types.this.erasure(outer)
5279 : outer);
5280 append(rawOuter ? '$' : '.');
5281 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
5282 append(rawOuter
5283 ? c.flatname.subName(c.owner.enclClass().flatname.length() + 1)
5284 : c.name);
5285 } else {
5286 append(externalize(c.flatname));
5287 }
5288 if (ct.getTypeArguments().nonEmpty()) {
5289 append('<');
5290 assembleSig(ct.getTypeArguments());
5291 append('>');
5292 }
5293 }
5294
5295 public void assembleParamsSig(List<Type> typarams) {
5296 append('<');
5297 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
5298 Type.TypeVar tvar = (Type.TypeVar) ts.head;
5299 append(tvar.tsym.name);
5300 List<Type> bounds = Types.this.getBounds(tvar);
5301 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
5302 append(':');
5303 }
5304 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
5305 append(':');
5306 assembleSig(l.head);
5307 }
5308 }
5309 append('>');
5310 }
5311
5312 public void assembleSig(List<Type> types) {
5313 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
5314 assembleSig(ts.head);
5315 }
5316 }
5317 }
5318
5319 public Type constantType(LoadableConstant c) {
5320 switch (c.poolTag()) {
5321 case ClassFile.CONSTANT_Class:
5322 return syms.classType;
5323 case ClassFile.CONSTANT_String:
5324 return syms.stringType;
5325 case ClassFile.CONSTANT_Integer:
5326 return syms.intType;
5327 case ClassFile.CONSTANT_Float:
5328 return syms.floatType;
5329 case ClassFile.CONSTANT_Long:
5330 return syms.longType;
5331 case ClassFile.CONSTANT_Double:
5332 return syms.doubleType;
5333 case ClassFile.CONSTANT_MethodHandle:
5334 return syms.methodHandleType;
5335 case ClassFile.CONSTANT_MethodType:
5336 return syms.methodTypeType;
5337 case ClassFile.CONSTANT_Dynamic:
5338 return ((DynamicVarSymbol)c).type;
5339 default:
5340 throw new AssertionError("Not a loadable constant: " + c.poolTag());
5341 }
5342 }
5343 // </editor-fold>
5344
5345 public void newRound() {
5346 descCache._map.clear();
5347 isDerivedRawCache.clear();
5348 implCache._map.clear();
5349 membersCache._map.clear();
5350 closureCache.clear();
5351 }
5352 }