1 /*
2 * Copyright (c) 1999, 2006, 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.comp;
27
28 import java.util.*;
29 import java.util.Set;
30
31 import com.sun.tools.javac.code.*;
32 import com.sun.tools.javac.jvm.*;
33 import com.sun.tools.javac.tree.*;
34 import com.sun.tools.javac.util.*;
35 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
36 import com.sun.tools.javac.util.List;
37
38 import com.sun.tools.javac.tree.JCTree.*;
39 import com.sun.tools.javac.code.Lint;
40 import com.sun.tools.javac.code.Lint.LintCategory;
41 import com.sun.tools.javac.code.Type.*;
42 import com.sun.tools.javac.code.Symbol.*;
43
44 import static com.sun.tools.javac.code.Flags.*;
45 import static com.sun.tools.javac.code.Kinds.*;
46 import static com.sun.tools.javac.code.TypeTags.*;
47
48 /** Type checking helper class for the attribution phase.
49 *
50 * <p><b>This is NOT part of any supported API.
51 * If you write code that depends on this, you do so at your own risk.
52 * This code and its internal interfaces are subject to change or
53 * deletion without notice.</b>
54 */
55 public class Check {
56 protected static final Context.Key<Check> checkKey =
57 new Context.Key<Check>();
58
59 private final Name.Table names;
60 private final Log log;
61 private final Symtab syms;
62 private final Infer infer;
63 private final Target target;
64 private final Source source;
65 private final Types types;
66 private final boolean skipAnnotations;
67 private final TreeInfo treeinfo;
68
69 // The set of lint options currently in effect. It is initialized
70 // from the context, and then is set/reset as needed by Attr as it
71 // visits all the various parts of the trees during attribution.
72 private Lint lint;
73
74 public static Check instance(Context context) {
75 Check instance = context.get(checkKey);
76 if (instance == null)
77 instance = new Check(context);
78 return instance;
79 }
80
81 protected Check(Context context) {
82 context.put(checkKey, this);
83
84 names = Name.Table.instance(context);
85 log = Log.instance(context);
86 syms = Symtab.instance(context);
87 infer = Infer.instance(context);
88 this.types = Types.instance(context);
89 Options options = Options.instance(context);
90 target = Target.instance(context);
91 source = Source.instance(context);
92 lint = Lint.instance(context);
93 treeinfo = TreeInfo.instance(context);
94
95 Source source = Source.instance(context);
96 allowGenerics = source.allowGenerics();
97 allowAnnotations = source.allowAnnotations();
98 complexInference = options.get("-complexinference") != null;
99 skipAnnotations = options.get("skipAnnotations") != null;
100
101 boolean verboseDeprecated = lint.isEnabled(LintCategory.DEPRECATION);
102 boolean verboseUnchecked = lint.isEnabled(LintCategory.UNCHECKED);
103 boolean enforceMandatoryWarnings = source.enforceMandatoryWarnings();
104
105 deprecationHandler = new MandatoryWarningHandler(log,verboseDeprecated,
106 enforceMandatoryWarnings, "deprecated");
107 uncheckedHandler = new MandatoryWarningHandler(log, verboseUnchecked,
108 enforceMandatoryWarnings, "unchecked");
109 }
110
111 /** Switch: generics enabled?
112 */
113 boolean allowGenerics;
114
115 /** Switch: annotations enabled?
116 */
117 boolean allowAnnotations;
118
119 /** Switch: -complexinference option set?
120 */
121 boolean complexInference;
122
123 /** A table mapping flat names of all compiled classes in this run to their
124 * symbols; maintained from outside.
125 */
126 public Map<Name,ClassSymbol> compiled = new HashMap<Name, ClassSymbol>();
127
128 /** A handler for messages about deprecated usage.
129 */
130 private MandatoryWarningHandler deprecationHandler;
131
132 /** A handler for messages about unchecked or unsafe usage.
133 */
134 private MandatoryWarningHandler uncheckedHandler;
135
136
137 /* *************************************************************************
138 * Errors and Warnings
139 **************************************************************************/
140
141 Lint setLint(Lint newLint) {
142 Lint prev = lint;
143 lint = newLint;
144 return prev;
145 }
146
147 /** Warn about deprecated symbol.
148 * @param pos Position to be used for error reporting.
149 * @param sym The deprecated symbol.
150 */
151 void warnDeprecated(DiagnosticPosition pos, Symbol sym) {
152 if (!lint.isSuppressed(LintCategory.DEPRECATION))
153 deprecationHandler.report(pos, "has.been.deprecated", sym, sym.location());
154 }
155
156 /** Warn about unchecked operation.
157 * @param pos Position to be used for error reporting.
158 * @param msg A string describing the problem.
159 */
160 public void warnUnchecked(DiagnosticPosition pos, String msg, Object... args) {
161 if (!lint.isSuppressed(LintCategory.UNCHECKED))
162 uncheckedHandler.report(pos, msg, args);
163 }
164
165 /**
166 * Report any deferred diagnostics.
167 */
168 public void reportDeferredDiagnostics() {
169 deprecationHandler.reportDeferredDiagnostic();
170 uncheckedHandler.reportDeferredDiagnostic();
171 }
172
173
174 /** Report a failure to complete a class.
175 * @param pos Position to be used for error reporting.
176 * @param ex The failure to report.
177 */
178 public Type completionError(DiagnosticPosition pos, CompletionFailure ex) {
179 log.error(pos, "cant.access", ex.sym, ex.errmsg);
180 if (ex instanceof ClassReader.BadClassFile) throw new Abort();
181 else return syms.errType;
182 }
183
184 /** Report a type error.
185 * @param pos Position to be used for error reporting.
186 * @param problem A string describing the error.
187 * @param found The type that was found.
188 * @param req The type that was required.
189 */
190 Type typeError(DiagnosticPosition pos, Object problem, Type found, Type req) {
191 log.error(pos, "prob.found.req",
192 problem, found, req);
193 return syms.errType;
194 }
195
196 Type typeError(DiagnosticPosition pos, String problem, Type found, Type req, Object explanation) {
197 log.error(pos, "prob.found.req.1", problem, found, req, explanation);
198 return syms.errType;
199 }
200
201 /** Report an error that wrong type tag was found.
202 * @param pos Position to be used for error reporting.
203 * @param required An internationalized string describing the type tag
204 * required.
205 * @param found The type that was found.
206 */
207 Type typeTagError(DiagnosticPosition pos, Object required, Object found) {
208 log.error(pos, "type.found.req", found, required);
209 return syms.errType;
210 }
211
212 /** Report an error that symbol cannot be referenced before super
213 * has been called.
214 * @param pos Position to be used for error reporting.
215 * @param sym The referenced symbol.
216 */
217 void earlyRefError(DiagnosticPosition pos, Symbol sym) {
218 log.error(pos, "cant.ref.before.ctor.called", sym);
219 }
220
221 /** Report duplicate declaration error.
222 */
223 void duplicateError(DiagnosticPosition pos, Symbol sym) {
224 if (!sym.type.isErroneous()) {
225 log.error(pos, "already.defined", sym, sym.location());
226 }
227 }
228
229 /** Report array/varargs duplicate declaration
230 */
231 void varargsDuplicateError(DiagnosticPosition pos, Symbol sym1, Symbol sym2) {
232 if (!sym1.type.isErroneous() && !sym2.type.isErroneous()) {
233 log.error(pos, "array.and.varargs", sym1, sym2, sym2.location());
234 }
235 }
236
237 /* ************************************************************************
238 * duplicate declaration checking
239 *************************************************************************/
240
241 /** Check that variable does not hide variable with same name in
242 * immediately enclosing local scope.
243 * @param pos Position for error reporting.
244 * @param v The symbol.
245 * @param s The scope.
246 */
247 void checkTransparentVar(DiagnosticPosition pos, VarSymbol v, Scope s) {
248 if (s.next != null) {
249 for (Scope.Entry e = s.next.lookup(v.name);
250 e.scope != null && e.sym.owner == v.owner;
251 e = e.next()) {
252 if (e.sym.kind == VAR &&
253 (e.sym.owner.kind & (VAR | MTH)) != 0 &&
254 v.name != names.error) {
255 duplicateError(pos, e.sym);
256 return;
257 }
258 }
259 }
260 }
261
262 /** Check that a class or interface does not hide a class or
263 * interface with same name in immediately enclosing local scope.
264 * @param pos Position for error reporting.
265 * @param c The symbol.
266 * @param s The scope.
267 */
268 void checkTransparentClass(DiagnosticPosition pos, ClassSymbol c, Scope s) {
269 if (s.next != null) {
270 for (Scope.Entry e = s.next.lookup(c.name);
271 e.scope != null && e.sym.owner == c.owner;
272 e = e.next()) {
273 if (e.sym.kind == TYP &&
274 (e.sym.owner.kind & (VAR | MTH)) != 0 &&
275 c.name != names.error) {
276 duplicateError(pos, e.sym);
277 return;
278 }
279 }
280 }
281 }
282
283 /** Check that class does not have the same name as one of
284 * its enclosing classes, or as a class defined in its enclosing scope.
285 * return true if class is unique in its enclosing scope.
286 * @param pos Position for error reporting.
287 * @param name The class name.
288 * @param s The enclosing scope.
289 */
290 boolean checkUniqueClassName(DiagnosticPosition pos, Name name, Scope s) {
291 for (Scope.Entry e = s.lookup(name); e.scope == s; e = e.next()) {
292 if (e.sym.kind == TYP && e.sym.name != names.error) {
293 duplicateError(pos, e.sym);
294 return false;
295 }
296 }
297 for (Symbol sym = s.owner; sym != null; sym = sym.owner) {
298 if (sym.kind == TYP && sym.name == name && sym.name != names.error) {
299 duplicateError(pos, sym);
300 return true;
301 }
302 }
303 return true;
304 }
305
306 /* *************************************************************************
307 * Class name generation
308 **************************************************************************/
309
310 /** Return name of local class.
311 * This is of the form <enclClass> $ n <classname>
312 * where
313 * enclClass is the flat name of the enclosing class,
314 * classname is the simple name of the local class
315 */
316 Name localClassName(ClassSymbol c) {
317 for (int i=1; ; i++) {
318 Name flatname = names.
319 fromString("" + c.owner.enclClass().flatname +
320 target.syntheticNameChar() + i +
321 c.name);
322 if (compiled.get(flatname) == null) return flatname;
323 }
324 }
325
326 /* *************************************************************************
327 * Type Checking
328 **************************************************************************/
329
330 /** Check that a given type is assignable to a given proto-type.
331 * If it is, return the type, otherwise return errType.
332 * @param pos Position to be used for error reporting.
333 * @param found The type that was found.
334 * @param req The type that was required.
335 */
336 Type checkType(DiagnosticPosition pos, Type found, Type req) {
337 if (req.tag == ERROR)
338 return req;
339 if (found.tag == FORALL)
340 return instantiatePoly(pos, (ForAll)found, req, convertWarner(pos, found, req));
341 if (req.tag == NONE)
342 return found;
343 if (types.isAssignable(found, req, convertWarner(pos, found, req)))
344 return found;
345 if (found.tag <= DOUBLE && req.tag <= DOUBLE)
346 return typeError(pos, JCDiagnostic.fragment("possible.loss.of.precision"), found, req);
347 if (found.isSuperBound()) {
348 log.error(pos, "assignment.from.super-bound", found);
349 return syms.errType;
350 }
351 if (req.isExtendsBound()) {
352 log.error(pos, "assignment.to.extends-bound", req);
353 return syms.errType;
354 }
355 return typeError(pos, JCDiagnostic.fragment("incompatible.types"), found, req);
356 }
357
358 /** Instantiate polymorphic type to some prototype, unless
359 * prototype is `anyPoly' in which case polymorphic type
360 * is returned unchanged.
361 */
362 Type instantiatePoly(DiagnosticPosition pos, ForAll t, Type pt, Warner warn) {
363 if (pt == Infer.anyPoly && complexInference) {
364 return t;
365 } else if (pt == Infer.anyPoly || pt.tag == NONE) {
366 Type newpt = t.qtype.tag <= VOID ? t.qtype : syms.objectType;
367 return instantiatePoly(pos, t, newpt, warn);
368 } else if (pt.tag == ERROR) {
369 return pt;
370 } else {
371 try {
372 return infer.instantiateExpr(t, pt, warn);
373 } catch (Infer.NoInstanceException ex) {
374 if (ex.isAmbiguous) {
375 JCDiagnostic d = ex.getDiagnostic();
376 log.error(pos,
377 "undetermined.type" + (d!=null ? ".1" : ""),
378 t, d);
379 return syms.errType;
380 } else {
381 JCDiagnostic d = ex.getDiagnostic();
382 return typeError(pos,
383 JCDiagnostic.fragment("incompatible.types" + (d!=null ? ".1" : ""), d),
384 t, pt);
385 }
386 }
387 }
388 }
389
390 /** Check that a given type can be cast to a given target type.
391 * Return the result of the cast.
392 * @param pos Position to be used for error reporting.
393 * @param found The type that is being cast.
394 * @param req The target type of the cast.
395 */
396 Type checkCastable(DiagnosticPosition pos, Type found, Type req) {
397 if (found.tag == FORALL) {
398 instantiatePoly(pos, (ForAll) found, req, castWarner(pos, found, req));
399 return req;
400 } else if (types.isCastable(found, req, castWarner(pos, found, req))) {
401 return req;
402 } else {
403 return typeError(pos,
404 JCDiagnostic.fragment("inconvertible.types"),
405 found, req);
406 }
407 }
408 //where
409 /** Is type a type variable, or a (possibly multi-dimensional) array of
410 * type variables?
411 */
412 boolean isTypeVar(Type t) {
413 return t.tag == TYPEVAR || t.tag == ARRAY && isTypeVar(types.elemtype(t));
414 }
415
416 /** Check that a type is within some bounds.
417 *
418 * Used in TypeApply to verify that, e.g., X in V<X> is a valid
419 * type argument.
420 * @param pos Position to be used for error reporting.
421 * @param a The type that should be bounded by bs.
422 * @param bs The bound.
423 */
424 private void checkExtends(DiagnosticPosition pos, Type a, TypeVar bs) {
425 if (a.isUnbound()) {
426 return;
427 } else if (a.tag != WILDCARD) {
428 a = types.upperBound(a);
429 for (List<Type> l = types.getBounds(bs); l.nonEmpty(); l = l.tail) {
430 if (!types.isSubtype(a, l.head)) {
431 log.error(pos, "not.within.bounds", a);
432 return;
433 }
434 }
435 } else if (a.isExtendsBound()) {
436 if (!types.isCastable(bs.getUpperBound(), types.upperBound(a), Warner.noWarnings))
437 log.error(pos, "not.within.bounds", a);
438 } else if (a.isSuperBound()) {
439 if (types.notSoftSubtype(types.lowerBound(a), bs.getUpperBound()))
440 log.error(pos, "not.within.bounds", a);
441 }
442 }
443
444 /** Check that type is different from 'void'.
445 * @param pos Position to be used for error reporting.
446 * @param t The type to be checked.
447 */
448 Type checkNonVoid(DiagnosticPosition pos, Type t) {
449 if (t.tag == VOID) {
450 log.error(pos, "void.not.allowed.here");
451 return syms.errType;
452 } else {
453 return t;
454 }
455 }
456
457 /** Check that type is a class or interface type.
458 * @param pos Position to be used for error reporting.
459 * @param t The type to be checked.
460 */
461 Type checkClassType(DiagnosticPosition pos, Type t) {
462 if (t.tag != CLASS && t.tag != ERROR)
463 return typeTagError(pos,
464 JCDiagnostic.fragment("type.req.class"),
465 (t.tag == TYPEVAR)
466 ? JCDiagnostic.fragment("type.parameter", t)
467 : t);
468 else
469 return t;
470 }
471
472 /** Check that type is a class or interface type.
473 * @param pos Position to be used for error reporting.
474 * @param t The type to be checked.
475 * @param noBounds True if type bounds are illegal here.
476 */
477 Type checkClassType(DiagnosticPosition pos, Type t, boolean noBounds) {
478 t = checkClassType(pos, t);
479 if (noBounds && t.isParameterized()) {
480 List<Type> args = t.getTypeArguments();
481 while (args.nonEmpty()) {
482 if (args.head.tag == WILDCARD)
483 return typeTagError(pos,
484 log.getLocalizedString("type.req.exact"),
485 args.head);
486 args = args.tail;
487 }
488 }
489 return t;
490 }
491
492 /** Check that type is a reifiable class, interface or array type.
493 * @param pos Position to be used for error reporting.
494 * @param t The type to be checked.
495 */
496 Type checkReifiableReferenceType(DiagnosticPosition pos, Type t) {
497 if (t.tag != CLASS && t.tag != ARRAY && t.tag != ERROR) {
498 return typeTagError(pos,
499 JCDiagnostic.fragment("type.req.class.array"),
500 t);
501 } else if (!types.isReifiable(t)) {
502 log.error(pos, "illegal.generic.type.for.instof");
503 return syms.errType;
504 } else {
505 return t;
506 }
507 }
508
509 /** Check that type is a reference type, i.e. a class, interface or array type
510 * or a type variable.
511 * @param pos Position to be used for error reporting.
512 * @param t The type to be checked.
513 */
514 Type checkRefType(DiagnosticPosition pos, Type t) {
515 switch (t.tag) {
516 case CLASS:
517 case ARRAY:
518 case TYPEVAR:
519 case WILDCARD:
520 case ERROR:
521 return t;
522 default:
523 return typeTagError(pos,
524 JCDiagnostic.fragment("type.req.ref"),
525 t);
526 }
527 }
528
529 /** Check that type is a null or reference type.
530 * @param pos Position to be used for error reporting.
531 * @param t The type to be checked.
532 */
533 Type checkNullOrRefType(DiagnosticPosition pos, Type t) {
534 switch (t.tag) {
535 case CLASS:
536 case ARRAY:
537 case TYPEVAR:
538 case WILDCARD:
539 case BOT:
540 case ERROR:
541 return t;
542 default:
543 return typeTagError(pos,
544 JCDiagnostic.fragment("type.req.ref"),
545 t);
546 }
547 }
548
549 /** Check that flag set does not contain elements of two conflicting sets. s
550 * Return true if it doesn't.
551 * @param pos Position to be used for error reporting.
552 * @param flags The set of flags to be checked.
553 * @param set1 Conflicting flags set #1.
554 * @param set2 Conflicting flags set #2.
555 */
556 boolean checkDisjoint(DiagnosticPosition pos, long flags, long set1, long set2) {
557 if ((flags & set1) != 0 && (flags & set2) != 0) {
558 log.error(pos,
559 "illegal.combination.of.modifiers",
560 TreeInfo.flagNames(TreeInfo.firstFlag(flags & set1)),
561 TreeInfo.flagNames(TreeInfo.firstFlag(flags & set2)));
562 return false;
563 } else
564 return true;
565 }
566
567 /** Check that given modifiers are legal for given symbol and
568 * return modifiers together with any implicit modififiers for that symbol.
569 * Warning: we can't use flags() here since this method
570 * is called during class enter, when flags() would cause a premature
571 * completion.
572 * @param pos Position to be used for error reporting.
573 * @param flags The set of modifiers given in a definition.
574 * @param sym The defined symbol.
575 */
576 long checkFlags(DiagnosticPosition pos, long flags, Symbol sym, JCTree tree) {
577 long mask;
578 long implicit = 0;
579 switch (sym.kind) {
580 case VAR:
581 if (sym.owner.kind != TYP)
582 mask = LocalVarFlags;
583 else if ((sym.owner.flags_field & INTERFACE) != 0)
584 mask = implicit = InterfaceVarFlags;
585 else
586 mask = VarFlags;
587 break;
588 case MTH:
589 if (sym.name == names.init) {
590 if ((sym.owner.flags_field & ENUM) != 0) {
591 // enum constructors cannot be declared public or
592 // protected and must be implicitly or explicitly
593 // private
594 implicit = PRIVATE;
595 mask = PRIVATE;
596 } else
597 mask = ConstructorFlags;
598 } else if ((sym.owner.flags_field & INTERFACE) != 0)
599 mask = implicit = InterfaceMethodFlags;
600 else {
601 mask = MethodFlags;
602 }
603 // Imply STRICTFP if owner has STRICTFP set.
604 if (((flags|implicit) & Flags.ABSTRACT) == 0)
605 implicit |= sym.owner.flags_field & STRICTFP;
606 break;
607 case TYP:
608 if (sym.isLocal()) {
609 mask = LocalClassFlags;
610 if (sym.name.len == 0) { // Anonymous class
611 // Anonymous classes in static methods are themselves static;
612 // that's why we admit STATIC here.
613 mask |= STATIC;
614 // JLS: Anonymous classes are final.
615 implicit |= FINAL;
616 }
617 if ((sym.owner.flags_field & STATIC) == 0 &&
618 (flags & ENUM) != 0)
619 log.error(pos, "enums.must.be.static");
620 } else if (sym.owner.kind == TYP) {
621 mask = MemberClassFlags;
622 if (sym.owner.owner.kind == PCK ||
623 (sym.owner.flags_field & STATIC) != 0)
624 mask |= STATIC;
625 else if ((flags & ENUM) != 0)
626 log.error(pos, "enums.must.be.static");
627 // Nested interfaces and enums are always STATIC (Spec ???)
628 if ((flags & (INTERFACE | ENUM)) != 0 ) implicit = STATIC;
629 } else {
630 mask = ClassFlags;
631 }
632 // Interfaces are always ABSTRACT
633 if ((flags & INTERFACE) != 0) implicit |= ABSTRACT;
634
635 if ((flags & ENUM) != 0) {
636 // enums can't be declared abstract or final
637 mask &= ~(ABSTRACT | FINAL);
638 implicit |= implicitEnumFinalFlag(tree);
639 }
640 // Imply STRICTFP if owner has STRICTFP set.
641 implicit |= sym.owner.flags_field & STRICTFP;
642 break;
643 default:
644 throw new AssertionError();
645 }
646 long illegal = flags & StandardFlags & ~mask;
647 if (illegal != 0) {
648 if ((illegal & INTERFACE) != 0) {
649 log.error(pos, "intf.not.allowed.here");
650 mask |= INTERFACE;
651 }
652 else {
653 log.error(pos,
654 "mod.not.allowed.here", TreeInfo.flagNames(illegal));
655 }
656 }
657 else if ((sym.kind == TYP ||
658 // ISSUE: Disallowing abstract&private is no longer appropriate
659 // in the presence of inner classes. Should it be deleted here?
660 checkDisjoint(pos, flags,
661 ABSTRACT,
662 PRIVATE | STATIC))
663 &&
664 checkDisjoint(pos, flags,
665 ABSTRACT | INTERFACE,
666 FINAL | NATIVE | SYNCHRONIZED)
667 &&
668 checkDisjoint(pos, flags,
669 PUBLIC,
670 PRIVATE | PROTECTED)
671 &&
672 checkDisjoint(pos, flags,
673 PRIVATE,
674 PUBLIC | PROTECTED)
675 &&
676 checkDisjoint(pos, flags,
677 FINAL,
678 VOLATILE)
679 &&
680 (sym.kind == TYP ||
681 checkDisjoint(pos, flags,
682 ABSTRACT | NATIVE,
683 STRICTFP))) {
684 // skip
685 }
686 return flags & (mask | ~StandardFlags) | implicit;
687 }
688
689
690 /** Determine if this enum should be implicitly final.
691 *
692 * If the enum has no specialized enum contants, it is final.
693 *
694 * If the enum does have specialized enum contants, it is
695 * <i>not</i> final.
696 */
697 private long implicitEnumFinalFlag(JCTree tree) {
698 if (tree.getTag() != JCTree.CLASSDEF) return 0;
699 class SpecialTreeVisitor extends JCTree.Visitor {
700 boolean specialized;
701 SpecialTreeVisitor() {
702 this.specialized = false;
703 };
704
705 public void visitTree(JCTree tree) { /* no-op */ }
706
707 public void visitVarDef(JCVariableDecl tree) {
708 if ((tree.mods.flags & ENUM) != 0) {
709 if (tree.init instanceof JCNewClass &&
710 ((JCNewClass) tree.init).def != null) {
711 specialized = true;
712 }
713 }
714 }
715 }
716
717 SpecialTreeVisitor sts = new SpecialTreeVisitor();
718 JCClassDecl cdef = (JCClassDecl) tree;
719 for (JCTree defs: cdef.defs) {
720 defs.accept(sts);
721 if (sts.specialized) return 0;
722 }
723 return FINAL;
724 }
725
726 /* *************************************************************************
727 * Type Validation
728 **************************************************************************/
729
730 /** Validate a type expression. That is,
731 * check that all type arguments of a parametric type are within
732 * their bounds. This must be done in a second phase after type attributon
733 * since a class might have a subclass as type parameter bound. E.g:
734 *
735 * class B<A extends C> { ... }
736 * class C extends B<C> { ... }
737 *
738 * and we can't make sure that the bound is already attributed because
739 * of possible cycles.
740 */
741 private Validator validator = new Validator();
742
743 /** Visitor method: Validate a type expression, if it is not null, catching
744 * and reporting any completion failures.
745 */
746 void validate(JCTree tree) {
747 try {
748 if (tree != null) tree.accept(validator);
749 } catch (CompletionFailure ex) {
750 completionError(tree.pos(), ex);
751 }
752 }
753
754 /** Visitor method: Validate a list of type expressions.
755 */
756 void validate(List<? extends JCTree> trees) {
757 for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail)
758 validate(l.head);
759 }
760
761 /** Visitor method: Validate a list of type parameters.
762 */
763 void validateTypeParams(List<JCTypeParameter> trees) {
764 for (List<JCTypeParameter> l = trees; l.nonEmpty(); l = l.tail)
765 validate(l.head);
766 }
767
768 /** A visitor class for type validation.
769 */
770 class Validator extends JCTree.Visitor {
771
772 public void visitTypeArray(JCArrayTypeTree tree) {
773 validate(tree.elemtype);
774 }
775
776 public void visitTypeApply(JCTypeApply tree) {
777 if (tree.type.tag == CLASS) {
778 List<Type> formals = tree.type.tsym.type.getTypeArguments();
779 List<Type> actuals = tree.type.getTypeArguments();
780 List<JCExpression> args = tree.arguments;
781 List<Type> forms = formals;
782 ListBuffer<TypeVar> tvars_buf = new ListBuffer<TypeVar>();
783
784 // For matching pairs of actual argument types `a' and
785 // formal type parameters with declared bound `b' ...
786 while (args.nonEmpty() && forms.nonEmpty()) {
787 validate(args.head);
788
789 // exact type arguments needs to know their
790 // bounds (for upper and lower bound
791 // calculations). So we create new TypeVars with
792 // bounds substed with actuals.
793 tvars_buf.append(types.substBound(((TypeVar)forms.head),
794 formals,
795 Type.removeBounds(actuals)));
796
797 args = args.tail;
798 forms = forms.tail;
799 }
800
801 args = tree.arguments;
802 List<TypeVar> tvars = tvars_buf.toList();
803 while (args.nonEmpty() && tvars.nonEmpty()) {
804 // Let the actual arguments know their bound
805 args.head.type.withTypeVar(tvars.head);
806 args = args.tail;
807 tvars = tvars.tail;
808 }
809
810 args = tree.arguments;
811 tvars = tvars_buf.toList();
812 while (args.nonEmpty() && tvars.nonEmpty()) {
813 checkExtends(args.head.pos(),
814 args.head.type,
815 tvars.head);
816 args = args.tail;
817 tvars = tvars.tail;
818 }
819
820 // Check that this type is either fully parameterized, or
821 // not parameterized at all.
822 if (tree.type.getEnclosingType().isRaw())
823 log.error(tree.pos(), "improperly.formed.type.inner.raw.param");
824 if (tree.clazz.getTag() == JCTree.SELECT)
825 visitSelectInternal((JCFieldAccess)tree.clazz);
826 }
827 }
828
829 public void visitTypeParameter(JCTypeParameter tree) {
830 validate(tree.bounds);
831 checkClassBounds(tree.pos(), tree.type);
832 }
833
834 @Override
835 public void visitWildcard(JCWildcard tree) {
836 if (tree.inner != null)
837 validate(tree.inner);
838 }
839
840 public void visitSelect(JCFieldAccess tree) {
841 if (tree.type.tag == CLASS) {
842 visitSelectInternal(tree);
843
844 // Check that this type is either fully parameterized, or
845 // not parameterized at all.
846 if (tree.selected.type.isParameterized() && tree.type.tsym.type.getTypeArguments().nonEmpty())
847 log.error(tree.pos(), "improperly.formed.type.param.missing");
848 }
849 }
850 public void visitSelectInternal(JCFieldAccess tree) {
851 if (tree.type.getEnclosingType().tag != CLASS &&
852 tree.selected.type.isParameterized()) {
853 // The enclosing type is not a class, so we are
854 // looking at a static member type. However, the
855 // qualifying expression is parameterized.
856 log.error(tree.pos(), "cant.select.static.class.from.param.type");
857 } else {
858 // otherwise validate the rest of the expression
859 validate(tree.selected);
860 }
861 }
862
863 /** Default visitor method: do nothing.
864 */
865 public void visitTree(JCTree tree) {
866 }
867 }
868
869 /* *************************************************************************
870 * Exception checking
871 **************************************************************************/
872
873 /* The following methods treat classes as sets that contain
874 * the class itself and all their subclasses
875 */
876
877 /** Is given type a subtype of some of the types in given list?
878 */
879 boolean subset(Type t, List<Type> ts) {
880 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
881 if (types.isSubtype(t, l.head)) return true;
882 return false;
883 }
884
885 /** Is given type a subtype or supertype of
886 * some of the types in given list?
887 */
888 boolean intersects(Type t, List<Type> ts) {
889 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
890 if (types.isSubtype(t, l.head) || types.isSubtype(l.head, t)) return true;
891 return false;
892 }
893
894 /** Add type set to given type list, unless it is a subclass of some class
895 * in the list.
896 */
897 List<Type> incl(Type t, List<Type> ts) {
898 return subset(t, ts) ? ts : excl(t, ts).prepend(t);
899 }
900
901 /** Remove type set from type set list.
902 */
903 List<Type> excl(Type t, List<Type> ts) {
904 if (ts.isEmpty()) {
905 return ts;
906 } else {
907 List<Type> ts1 = excl(t, ts.tail);
908 if (types.isSubtype(ts.head, t)) return ts1;
909 else if (ts1 == ts.tail) return ts;
910 else return ts1.prepend(ts.head);
911 }
912 }
913
914 /** Form the union of two type set lists.
915 */
916 List<Type> union(List<Type> ts1, List<Type> ts2) {
917 List<Type> ts = ts1;
918 for (List<Type> l = ts2; l.nonEmpty(); l = l.tail)
919 ts = incl(l.head, ts);
920 return ts;
921 }
922
923 /** Form the difference of two type lists.
924 */
925 List<Type> diff(List<Type> ts1, List<Type> ts2) {
926 List<Type> ts = ts1;
927 for (List<Type> l = ts2; l.nonEmpty(); l = l.tail)
928 ts = excl(l.head, ts);
929 return ts;
930 }
931
932 /** Form the intersection of two type lists.
933 */
934 public List<Type> intersect(List<Type> ts1, List<Type> ts2) {
935 List<Type> ts = List.nil();
936 for (List<Type> l = ts1; l.nonEmpty(); l = l.tail)
937 if (subset(l.head, ts2)) ts = incl(l.head, ts);
938 for (List<Type> l = ts2; l.nonEmpty(); l = l.tail)
939 if (subset(l.head, ts1)) ts = incl(l.head, ts);
940 return ts;
941 }
942
943 /** Is exc an exception symbol that need not be declared?
944 */
945 boolean isUnchecked(ClassSymbol exc) {
946 return
947 exc.kind == ERR ||
948 exc.isSubClass(syms.errorType.tsym, types) ||
949 exc.isSubClass(syms.runtimeExceptionType.tsym, types);
950 }
951
952 /** Is exc an exception type that need not be declared?
953 */
954 boolean isUnchecked(Type exc) {
955 return
956 (exc.tag == TYPEVAR) ? isUnchecked(types.supertype(exc)) :
957 (exc.tag == CLASS) ? isUnchecked((ClassSymbol)exc.tsym) :
958 exc.tag == BOT;
959 }
960
961 /** Same, but handling completion failures.
962 */
963 boolean isUnchecked(DiagnosticPosition pos, Type exc) {
964 try {
965 return isUnchecked(exc);
966 } catch (CompletionFailure ex) {
967 completionError(pos, ex);
968 return true;
969 }
970 }
971
972 /** Is exc handled by given exception list?
973 */
974 boolean isHandled(Type exc, List<Type> handled) {
975 return isUnchecked(exc) || subset(exc, handled);
976 }
977
978 /** Return all exceptions in thrown list that are not in handled list.
979 * @param thrown The list of thrown exceptions.
980 * @param handled The list of handled exceptions.
981 */
982 List<Type> unHandled(List<Type> thrown, List<Type> handled) {
983 List<Type> unhandled = List.nil();
984 for (List<Type> l = thrown; l.nonEmpty(); l = l.tail)
985 if (!isHandled(l.head, handled)) unhandled = unhandled.prepend(l.head);
986 return unhandled;
987 }
988
989 /* *************************************************************************
990 * Overriding/Implementation checking
991 **************************************************************************/
992
993 /** The level of access protection given by a flag set,
994 * where PRIVATE is highest and PUBLIC is lowest.
995 */
996 static int protection(long flags) {
997 switch ((short)(flags & AccessFlags)) {
998 case PRIVATE: return 3;
999 case PROTECTED: return 1;
1000 default:
1001 case PUBLIC: return 0;
1002 case 0: return 2;
1003 }
1004 }
1005
1006 /** A string describing the access permission given by a flag set.
1007 * This always returns a space-separated list of Java Keywords.
1008 */
1009 private static String protectionString(long flags) {
1010 long flags1 = flags & AccessFlags;
1011 return (flags1 == 0) ? "package" : TreeInfo.flagNames(flags1);
1012 }
1013
1014 /** A customized "cannot override" error message.
1015 * @param m The overriding method.
1016 * @param other The overridden method.
1017 * @return An internationalized string.
1018 */
1019 static Object cannotOverride(MethodSymbol m, MethodSymbol other) {
1020 String key;
1021 if ((other.owner.flags() & INTERFACE) == 0)
1022 key = "cant.override";
1023 else if ((m.owner.flags() & INTERFACE) == 0)
1024 key = "cant.implement";
1025 else
1026 key = "clashes.with";
1027 return JCDiagnostic.fragment(key, m, m.location(), other, other.location());
1028 }
1029
1030 /** A customized "override" warning message.
1031 * @param m The overriding method.
1032 * @param other The overridden method.
1033 * @return An internationalized string.
1034 */
1035 static Object uncheckedOverrides(MethodSymbol m, MethodSymbol other) {
1036 String key;
1037 if ((other.owner.flags() & INTERFACE) == 0)
1038 key = "unchecked.override";
1039 else if ((m.owner.flags() & INTERFACE) == 0)
1040 key = "unchecked.implement";
1041 else
1042 key = "unchecked.clash.with";
1043 return JCDiagnostic.fragment(key, m, m.location(), other, other.location());
1044 }
1045
1046 /** A customized "override" warning message.
1047 * @param m The overriding method.
1048 * @param other The overridden method.
1049 * @return An internationalized string.
1050 */
1051 static Object varargsOverrides(MethodSymbol m, MethodSymbol other) {
1052 String key;
1053 if ((other.owner.flags() & INTERFACE) == 0)
1054 key = "varargs.override";
1055 else if ((m.owner.flags() & INTERFACE) == 0)
1056 key = "varargs.implement";
1057 else
1058 key = "varargs.clash.with";
1059 return JCDiagnostic.fragment(key, m, m.location(), other, other.location());
1060 }
1061
1062 /** Check that this method conforms with overridden method 'other'.
1063 * where `origin' is the class where checking started.
1064 * Complications:
1065 * (1) Do not check overriding of synthetic methods
1066 * (reason: they might be final).
1067 * todo: check whether this is still necessary.
1068 * (2) Admit the case where an interface proxy throws fewer exceptions
1069 * than the method it implements. Augment the proxy methods with the
1070 * undeclared exceptions in this case.
1071 * (3) When generics are enabled, admit the case where an interface proxy
1072 * has a result type
1073 * extended by the result type of the method it implements.
1074 * Change the proxies result type to the smaller type in this case.
1075 *
1076 * @param tree The tree from which positions
1077 * are extracted for errors.
1078 * @param m The overriding method.
1079 * @param other The overridden method.
1080 * @param origin The class of which the overriding method
1081 * is a member.
1082 */
1083 void checkOverride(JCTree tree,
1084 MethodSymbol m,
1085 MethodSymbol other,
1086 ClassSymbol origin) {
1087 // Don't check overriding of synthetic methods or by bridge methods.
1088 if ((m.flags() & (SYNTHETIC|BRIDGE)) != 0 || (other.flags() & SYNTHETIC) != 0) {
1089 return;
1090 }
1091
1092 // Error if static method overrides instance method (JLS 8.4.6.2).
1093 if ((m.flags() & STATIC) != 0 &&
1094 (other.flags() & STATIC) == 0) {
1095 log.error(TreeInfo.diagnosticPositionFor(m, tree), "override.static",
1096 cannotOverride(m, other));
1097 return;
1098 }
1099
1100 // Error if instance method overrides static or final
1101 // method (JLS 8.4.6.1).
1102 if ((other.flags() & FINAL) != 0 ||
1103 (m.flags() & STATIC) == 0 &&
1104 (other.flags() & STATIC) != 0) {
1105 log.error(TreeInfo.diagnosticPositionFor(m, tree), "override.meth",
1106 cannotOverride(m, other),
1107 TreeInfo.flagNames(other.flags() & (FINAL | STATIC)));
1108 return;
1109 }
1110
1111 if ((m.owner.flags() & ANNOTATION) != 0) {
1112 // handled in validateAnnotationMethod
1113 return;
1114 }
1115
1116 // Error if overriding method has weaker access (JLS 8.4.6.3).
1117 if ((origin.flags() & INTERFACE) == 0 &&
1118 protection(m.flags()) > protection(other.flags())) {
1119 log.error(TreeInfo.diagnosticPositionFor(m, tree), "override.weaker.access",
1120 cannotOverride(m, other),
1121 protectionString(other.flags()));
1122 return;
1123
1124 }
1125
1126 Type mt = types.memberType(origin.type, m);
1127 Type ot = types.memberType(origin.type, other);
1128 // Error if overriding result type is different
1129 // (or, in the case of generics mode, not a subtype) of
1130 // overridden result type. We have to rename any type parameters
1131 // before comparing types.
1132 List<Type> mtvars = mt.getTypeArguments();
1133 List<Type> otvars = ot.getTypeArguments();
1134 Type mtres = mt.getReturnType();
1135 Type otres = types.subst(ot.getReturnType(), otvars, mtvars);
1136
1137 overrideWarner.warned = false;
1138 boolean resultTypesOK =
1139 types.returnTypeSubstitutable(mt, ot, otres, overrideWarner);
1140 if (!resultTypesOK) {
1141 if (!source.allowCovariantReturns() &&
1142 m.owner != origin &&
1143 m.owner.isSubClass(other.owner, types)) {
1144 // allow limited interoperability with covariant returns
1145 } else {
1146 typeError(TreeInfo.diagnosticPositionFor(m, tree),
1147 JCDiagnostic.fragment("override.incompatible.ret",
1148 cannotOverride(m, other)),
1149 mtres, otres);
1150 return;
1151 }
1152 } else if (overrideWarner.warned) {
1153 warnUnchecked(TreeInfo.diagnosticPositionFor(m, tree),
1154 "prob.found.req",
1155 JCDiagnostic.fragment("override.unchecked.ret",
1156 uncheckedOverrides(m, other)),
1157 mtres, otres);
1158 }
1159
1160 // Error if overriding method throws an exception not reported
1161 // by overridden method.
1162 List<Type> otthrown = types.subst(ot.getThrownTypes(), otvars, mtvars);
1163 List<Type> unhandled = unHandled(mt.getThrownTypes(), otthrown);
1164 if (unhandled.nonEmpty()) {
1165 log.error(TreeInfo.diagnosticPositionFor(m, tree),
1166 "override.meth.doesnt.throw",
1167 cannotOverride(m, other),
1168 unhandled.head);
1169 return;
1170 }
1171
1172 // Optional warning if varargs don't agree
1173 if ((((m.flags() ^ other.flags()) & Flags.VARARGS) != 0)
1174 && lint.isEnabled(Lint.LintCategory.OVERRIDES)) {
1175 log.warning(TreeInfo.diagnosticPositionFor(m, tree),
1176 ((m.flags() & Flags.VARARGS) != 0)
1177 ? "override.varargs.missing"
1178 : "override.varargs.extra",
1179 varargsOverrides(m, other));
1180 }
1181
1182 // Warn if instance method overrides bridge method (compiler spec ??)
1183 if ((other.flags() & BRIDGE) != 0) {
1184 log.warning(TreeInfo.diagnosticPositionFor(m, tree), "override.bridge",
1185 uncheckedOverrides(m, other));
1186 }
1187
1188 // Warn if a deprecated method overridden by a non-deprecated one.
1189 if ((other.flags() & DEPRECATED) != 0
1190 && (m.flags() & DEPRECATED) == 0
1191 && m.outermostClass() != other.outermostClass()
1192 && !isDeprecatedOverrideIgnorable(other, origin)) {
1193 warnDeprecated(TreeInfo.diagnosticPositionFor(m, tree), other);
1194 }
1195 }
1196 // where
1197 private boolean isDeprecatedOverrideIgnorable(MethodSymbol m, ClassSymbol origin) {
1198 // If the method, m, is defined in an interface, then ignore the issue if the method
1199 // is only inherited via a supertype and also implemented in the supertype,
1200 // because in that case, we will rediscover the issue when examining the method
1201 // in the supertype.
1202 // If the method, m, is not defined in an interface, then the only time we need to
1203 // address the issue is when the method is the supertype implemementation: any other
1204 // case, we will have dealt with when examining the supertype classes
1205 ClassSymbol mc = m.enclClass();
1206 Type st = types.supertype(origin.type);
1207 if (st.tag != CLASS)
1208 return true;
1209 MethodSymbol stimpl = m.implementation((ClassSymbol)st.tsym, types, false);
1210
1211 if (mc != null && ((mc.flags() & INTERFACE) != 0)) {
1212 List<Type> intfs = types.interfaces(origin.type);
1213 return (intfs.contains(mc.type) ? false : (stimpl != null));
1214 }
1215 else
1216 return (stimpl != m);
1217 }
1218
1219
1220 // used to check if there were any unchecked conversions
1221 Warner overrideWarner = new Warner();
1222
1223 /** Check that a class does not inherit two concrete methods
1224 * with the same signature.
1225 * @param pos Position to be used for error reporting.
1226 * @param site The class type to be checked.
1227 */
1228 public void checkCompatibleConcretes(DiagnosticPosition pos, Type site) {
1229 Type sup = types.supertype(site);
1230 if (sup.tag != CLASS) return;
1231
1232 for (Type t1 = sup;
1233 t1.tsym.type.isParameterized();
1234 t1 = types.supertype(t1)) {
1235 for (Scope.Entry e1 = t1.tsym.members().elems;
1236 e1 != null;
1237 e1 = e1.sibling) {
1238 Symbol s1 = e1.sym;
1239 if (s1.kind != MTH ||
1240 (s1.flags() & (STATIC|SYNTHETIC|BRIDGE)) != 0 ||
1241 !s1.isInheritedIn(site.tsym, types) ||
1242 ((MethodSymbol)s1).implementation(site.tsym,
1243 types,
1244 true) != s1)
1245 continue;
1246 Type st1 = types.memberType(t1, s1);
1247 int s1ArgsLength = st1.getParameterTypes().length();
1248 if (st1 == s1.type) continue;
1249
1250 for (Type t2 = sup;
1251 t2.tag == CLASS;
1252 t2 = types.supertype(t2)) {
1253 for (Scope.Entry e2 = t1.tsym.members().lookup(s1.name);
1254 e2.scope != null;
1255 e2 = e2.next()) {
1256 Symbol s2 = e2.sym;
1257 if (s2 == s1 ||
1258 s2.kind != MTH ||
1259 (s2.flags() & (STATIC|SYNTHETIC|BRIDGE)) != 0 ||
1260 s2.type.getParameterTypes().length() != s1ArgsLength ||
1261 !s2.isInheritedIn(site.tsym, types) ||
1262 ((MethodSymbol)s2).implementation(site.tsym,
1263 types,
1264 true) != s2)
1265 continue;
1266 Type st2 = types.memberType(t2, s2);
1267 if (types.overrideEquivalent(st1, st2))
1268 log.error(pos, "concrete.inheritance.conflict",
1269 s1, t1, s2, t2, sup);
1270 }
1271 }
1272 }
1273 }
1274 }
1275
1276 /** Check that classes (or interfaces) do not each define an abstract
1277 * method with same name and arguments but incompatible return types.
1278 * @param pos Position to be used for error reporting.
1279 * @param t1 The first argument type.
1280 * @param t2 The second argument type.
1281 */
1282 public boolean checkCompatibleAbstracts(DiagnosticPosition pos,
1283 Type t1,
1284 Type t2) {
1285 return checkCompatibleAbstracts(pos, t1, t2,
1286 types.makeCompoundType(t1, t2));
1287 }
1288
1289 public boolean checkCompatibleAbstracts(DiagnosticPosition pos,
1290 Type t1,
1291 Type t2,
1292 Type site) {
1293 Symbol sym = firstIncompatibility(t1, t2, site);
1294 if (sym != null) {
1295 log.error(pos, "types.incompatible.diff.ret",
1296 t1, t2, sym.name +
1297 "(" + types.memberType(t2, sym).getParameterTypes() + ")");
1298 return false;
1299 }
1300 return true;
1301 }
1302
1303 /** Return the first method which is defined with same args
1304 * but different return types in two given interfaces, or null if none
1305 * exists.
1306 * @param t1 The first type.
1307 * @param t2 The second type.
1308 * @param site The most derived type.
1309 * @returns symbol from t2 that conflicts with one in t1.
1310 */
1311 private Symbol firstIncompatibility(Type t1, Type t2, Type site) {
1312 Map<TypeSymbol,Type> interfaces1 = new HashMap<TypeSymbol,Type>();
1313 closure(t1, interfaces1);
1314 Map<TypeSymbol,Type> interfaces2;
1315 if (t1 == t2)
1316 interfaces2 = interfaces1;
1317 else
1318 closure(t2, interfaces1, interfaces2 = new HashMap<TypeSymbol,Type>());
1319
1320 for (Type t3 : interfaces1.values()) {
1321 for (Type t4 : interfaces2.values()) {
1322 Symbol s = firstDirectIncompatibility(t3, t4, site);
1323 if (s != null) return s;
1324 }
1325 }
1326 return null;
1327 }
1328
1329 /** Compute all the supertypes of t, indexed by type symbol. */
1330 private void closure(Type t, Map<TypeSymbol,Type> typeMap) {
1331 if (t.tag != CLASS) return;
1332 if (typeMap.put(t.tsym, t) == null) {
1333 closure(types.supertype(t), typeMap);
1334 for (Type i : types.interfaces(t))
1335 closure(i, typeMap);
1336 }
1337 }
1338
1339 /** Compute all the supertypes of t, indexed by type symbol (except thise in typesSkip). */
1340 private void closure(Type t, Map<TypeSymbol,Type> typesSkip, Map<TypeSymbol,Type> typeMap) {
1341 if (t.tag != CLASS) return;
1342 if (typesSkip.get(t.tsym) != null) return;
1343 if (typeMap.put(t.tsym, t) == null) {
1344 closure(types.supertype(t), typesSkip, typeMap);
1345 for (Type i : types.interfaces(t))
1346 closure(i, typesSkip, typeMap);
1347 }
1348 }
1349
1350 /** Return the first method in t2 that conflicts with a method from t1. */
1351 private Symbol firstDirectIncompatibility(Type t1, Type t2, Type site) {
1352 for (Scope.Entry e1 = t1.tsym.members().elems; e1 != null; e1 = e1.sibling) {
1353 Symbol s1 = e1.sym;
1354 Type st1 = null;
1355 if (s1.kind != MTH || !s1.isInheritedIn(site.tsym, types)) continue;
1356 Symbol impl = ((MethodSymbol)s1).implementation(site.tsym, types, false);
1357 if (impl != null && (impl.flags() & ABSTRACT) == 0) continue;
1358 for (Scope.Entry e2 = t2.tsym.members().lookup(s1.name); e2.scope != null; e2 = e2.next()) {
1359 Symbol s2 = e2.sym;
1360 if (s1 == s2) continue;
1361 if (s2.kind != MTH || !s2.isInheritedIn(site.tsym, types)) continue;
1362 if (st1 == null) st1 = types.memberType(t1, s1);
1363 Type st2 = types.memberType(t2, s2);
1364 if (types.overrideEquivalent(st1, st2)) {
1365 List<Type> tvars1 = st1.getTypeArguments();
1366 List<Type> tvars2 = st2.getTypeArguments();
1367 Type rt1 = st1.getReturnType();
1368 Type rt2 = types.subst(st2.getReturnType(), tvars2, tvars1);
1369 boolean compat =
1370 types.isSameType(rt1, rt2) ||
1371 rt1.tag >= CLASS && rt2.tag >= CLASS &&
1372 (types.covariantReturnType(rt1, rt2, Warner.noWarnings) ||
1373 types.covariantReturnType(rt2, rt1, Warner.noWarnings));
1374 if (!compat) return s2;
1375 }
1376 }
1377 }
1378 return null;
1379 }
1380
1381 /** Check that a given method conforms with any method it overrides.
1382 * @param tree The tree from which positions are extracted
1383 * for errors.
1384 * @param m The overriding method.
1385 */
1386 void checkOverride(JCTree tree, MethodSymbol m) {
1387 ClassSymbol origin = (ClassSymbol)m.owner;
1388 if ((origin.flags() & ENUM) != 0 && names.finalize.equals(m.name))
1389 if (m.overrides(syms.enumFinalFinalize, origin, types, false)) {
1390 log.error(tree.pos(), "enum.no.finalize");
1391 return;
1392 }
1393 for (Type t = types.supertype(origin.type); t.tag == CLASS;
1394 t = types.supertype(t)) {
1395 TypeSymbol c = t.tsym;
1396 Scope.Entry e = c.members().lookup(m.name);
1397 while (e.scope != null) {
1398 if (m.overrides(e.sym, origin, types, false))
1399 checkOverride(tree, m, (MethodSymbol)e.sym, origin);
1400 e = e.next();
1401 }
1402 }
1403 }
1404
1405 /** Check that all abstract members of given class have definitions.
1406 * @param pos Position to be used for error reporting.
1407 * @param c The class.
1408 */
1409 void checkAllDefined(DiagnosticPosition pos, ClassSymbol c) {
1410 try {
1411 MethodSymbol undef = firstUndef(c, c);
1412 if (undef != null) {
1413 if ((c.flags() & ENUM) != 0 &&
1414 types.supertype(c.type).tsym == syms.enumSym &&
1415 (c.flags() & FINAL) == 0) {
1416 // add the ABSTRACT flag to an enum
1417 c.flags_field |= ABSTRACT;
1418 } else {
1419 MethodSymbol undef1 =
1420 new MethodSymbol(undef.flags(), undef.name,
1421 types.memberType(c.type, undef), undef.owner);
1422 log.error(pos, "does.not.override.abstract",
1423 c, undef1, undef1.location());
1424 }
1425 }
1426 } catch (CompletionFailure ex) {
1427 completionError(pos, ex);
1428 }
1429 }
1430 //where
1431 /** Return first abstract member of class `c' that is not defined
1432 * in `impl', null if there is none.
1433 */
1434 private MethodSymbol firstUndef(ClassSymbol impl, ClassSymbol c) {
1435 MethodSymbol undef = null;
1436 // Do not bother to search in classes that are not abstract,
1437 // since they cannot have abstract members.
1438 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
1439 Scope s = c.members();
1440 for (Scope.Entry e = s.elems;
1441 undef == null && e != null;
1442 e = e.sibling) {
1443 if (e.sym.kind == MTH &&
1444 (e.sym.flags() & (ABSTRACT|IPROXY)) == ABSTRACT) {
1445 MethodSymbol absmeth = (MethodSymbol)e.sym;
1446 MethodSymbol implmeth = absmeth.implementation(impl, types, true);
1447 if (implmeth == null || implmeth == absmeth)
1448 undef = absmeth;
1449 }
1450 }
1451 if (undef == null) {
1452 Type st = types.supertype(c.type);
1453 if (st.tag == CLASS)
1454 undef = firstUndef(impl, (ClassSymbol)st.tsym);
1455 }
1456 for (List<Type> l = types.interfaces(c.type);
1457 undef == null && l.nonEmpty();
1458 l = l.tail) {
1459 undef = firstUndef(impl, (ClassSymbol)l.head.tsym);
1460 }
1461 }
1462 return undef;
1463 }
1464
1465 /** Check for cyclic references. Issue an error if the
1466 * symbol of the type referred to has a LOCKED flag set.
1467 *
1468 * @param pos Position to be used for error reporting.
1469 * @param t The type referred to.
1470 */
1471 void checkNonCyclic(DiagnosticPosition pos, Type t) {
1472 checkNonCyclicInternal(pos, t);
1473 }
1474
1475
1476 void checkNonCyclic(DiagnosticPosition pos, TypeVar t) {
1477 checkNonCyclic1(pos, t, new HashSet<TypeVar>());
1478 }
1479
1480 private void checkNonCyclic1(DiagnosticPosition pos, Type t, Set<TypeVar> seen) {
1481 final TypeVar tv;
1482 if (seen.contains(t)) {
1483 tv = (TypeVar)t;
1484 tv.bound = new ErrorType();
1485 log.error(pos, "cyclic.inheritance", t);
1486 } else if (t.tag == TYPEVAR) {
1487 tv = (TypeVar)t;
1488 seen.add(tv);
1489 for (Type b : types.getBounds(tv))
1490 checkNonCyclic1(pos, b, seen);
1491 }
1492 }
1493
1494 /** Check for cyclic references. Issue an error if the
1495 * symbol of the type referred to has a LOCKED flag set.
1496 *
1497 * @param pos Position to be used for error reporting.
1498 * @param t The type referred to.
1499 * @returns True if the check completed on all attributed classes
1500 */
1501 private boolean checkNonCyclicInternal(DiagnosticPosition pos, Type t) {
1502 boolean complete = true; // was the check complete?
1503 //- System.err.println("checkNonCyclicInternal("+t+");");//DEBUG
1504 Symbol c = t.tsym;
1505 if ((c.flags_field & ACYCLIC) != 0) return true;
1506
1507 if ((c.flags_field & LOCKED) != 0) {
1508 noteCyclic(pos, (ClassSymbol)c);
1509 } else if (!c.type.isErroneous()) {
1510 try {
1511 c.flags_field |= LOCKED;
1512 if (c.type.tag == CLASS) {
1513 ClassType clazz = (ClassType)c.type;
1514 if (clazz.interfaces_field != null)
1515 for (List<Type> l=clazz.interfaces_field; l.nonEmpty(); l=l.tail)
1516 complete &= checkNonCyclicInternal(pos, l.head);
1517 if (clazz.supertype_field != null) {
1518 Type st = clazz.supertype_field;
1519 if (st != null && st.tag == CLASS)
1520 complete &= checkNonCyclicInternal(pos, st);
1521 }
1522 if (c.owner.kind == TYP)
1523 complete &= checkNonCyclicInternal(pos, c.owner.type);
1524 }
1525 } finally {
1526 c.flags_field &= ~LOCKED;
1527 }
1528 }
1529 if (complete)
1530 complete = ((c.flags_field & UNATTRIBUTED) == 0) && c.completer == null;
1531 if (complete) c.flags_field |= ACYCLIC;
1532 return complete;
1533 }
1534
1535 /** Note that we found an inheritance cycle. */
1536 private void noteCyclic(DiagnosticPosition pos, ClassSymbol c) {
1537 log.error(pos, "cyclic.inheritance", c);
1538 for (List<Type> l=types.interfaces(c.type); l.nonEmpty(); l=l.tail)
1539 l.head = new ErrorType((ClassSymbol)l.head.tsym);
1540 Type st = types.supertype(c.type);
1541 if (st.tag == CLASS)
1542 ((ClassType)c.type).supertype_field = new ErrorType((ClassSymbol)st.tsym);
1543 c.type = new ErrorType(c);
1544 c.flags_field |= ACYCLIC;
1545 }
1546
1547 /** Check that all methods which implement some
1548 * method conform to the method they implement.
1549 * @param tree The class definition whose members are checked.
1550 */
1551 void checkImplementations(JCClassDecl tree) {
1552 checkImplementations(tree, tree.sym);
1553 }
1554 //where
1555 /** Check that all methods which implement some
1556 * method in `ic' conform to the method they implement.
1557 */
1558 void checkImplementations(JCClassDecl tree, ClassSymbol ic) {
1559 ClassSymbol origin = tree.sym;
1560 for (List<Type> l = types.closure(ic.type); l.nonEmpty(); l = l.tail) {
1561 ClassSymbol lc = (ClassSymbol)l.head.tsym;
1562 if ((allowGenerics || origin != lc) && (lc.flags() & ABSTRACT) != 0) {
1563 for (Scope.Entry e=lc.members().elems; e != null; e=e.sibling) {
1564 if (e.sym.kind == MTH &&
1565 (e.sym.flags() & (STATIC|ABSTRACT)) == ABSTRACT) {
1566 MethodSymbol absmeth = (MethodSymbol)e.sym;
1567 MethodSymbol implmeth = absmeth.implementation(origin, types, false);
1568 if (implmeth != null && implmeth != absmeth &&
1569 (implmeth.owner.flags() & INTERFACE) ==
1570 (origin.flags() & INTERFACE)) {
1571 // don't check if implmeth is in a class, yet
1572 // origin is an interface. This case arises only
1573 // if implmeth is declared in Object. The reason is
1574 // that interfaces really don't inherit from
1575 // Object it's just that the compiler represents
1576 // things that way.
1577 checkOverride(tree, implmeth, absmeth, origin);
1578 }
1579 }
1580 }
1581 }
1582 }
1583 }
1584
1585 /** Check that all abstract methods implemented by a class are
1586 * mutually compatible.
1587 * @param pos Position to be used for error reporting.
1588 * @param c The class whose interfaces are checked.
1589 */
1590 void checkCompatibleSupertypes(DiagnosticPosition pos, Type c) {
1591 List<Type> supertypes = types.interfaces(c);
1592 Type supertype = types.supertype(c);
1593 if (supertype.tag == CLASS &&
1594 (supertype.tsym.flags() & ABSTRACT) != 0)
1595 supertypes = supertypes.prepend(supertype);
1596 for (List<Type> l = supertypes; l.nonEmpty(); l = l.tail) {
1597 if (allowGenerics && !l.head.getTypeArguments().isEmpty() &&
1598 !checkCompatibleAbstracts(pos, l.head, l.head, c))
1599 return;
1600 for (List<Type> m = supertypes; m != l; m = m.tail)
1601 if (!checkCompatibleAbstracts(pos, l.head, m.head, c))
1602 return;
1603 }
1604 checkCompatibleConcretes(pos, c);
1605 }
1606
1607 /** Check that class c does not implement directly or indirectly
1608 * the same parameterized interface with two different argument lists.
1609 * @param pos Position to be used for error reporting.
1610 * @param type The type whose interfaces are checked.
1611 */
1612 void checkClassBounds(DiagnosticPosition pos, Type type) {
1613 checkClassBounds(pos, new HashMap<TypeSymbol,Type>(), type);
1614 }
1615 //where
1616 /** Enter all interfaces of type `type' into the hash table `seensofar'
1617 * with their class symbol as key and their type as value. Make
1618 * sure no class is entered with two different types.
1619 */
1620 void checkClassBounds(DiagnosticPosition pos,
1621 Map<TypeSymbol,Type> seensofar,
1622 Type type) {
1623 if (type.isErroneous()) return;
1624 for (List<Type> l = types.interfaces(type); l.nonEmpty(); l = l.tail) {
1625 Type it = l.head;
1626 Type oldit = seensofar.put(it.tsym, it);
1627 if (oldit != null) {
1628 List<Type> oldparams = oldit.allparams();
1629 List<Type> newparams = it.allparams();
1630 if (!types.containsTypeEquivalent(oldparams, newparams))
1631 log.error(pos, "cant.inherit.diff.arg",
1632 it.tsym, Type.toString(oldparams),
1633 Type.toString(newparams));
1634 }
1635 checkClassBounds(pos, seensofar, it);
1636 }
1637 Type st = types.supertype(type);
1638 if (st != null) checkClassBounds(pos, seensofar, st);
1639 }
1640
1641 /** Enter interface into into set.
1642 * If it existed already, issue a "repeated interface" error.
1643 */
1644 void checkNotRepeated(DiagnosticPosition pos, Type it, Set<Type> its) {
1645 if (its.contains(it))
1646 log.error(pos, "repeated.interface");
1647 else {
1648 its.add(it);
1649 }
1650 }
1651
1652 /* *************************************************************************
1653 * Check annotations
1654 **************************************************************************/
1655
1656 /** Annotation types are restricted to primitives, String, an
1657 * enum, an annotation, Class, Class<?>, Class<? extends
1658 * Anything>, arrays of the preceding.
1659 */
1660 void validateAnnotationType(JCTree restype) {
1661 // restype may be null if an error occurred, so don't bother validating it
1662 if (restype != null) {
1663 validateAnnotationType(restype.pos(), restype.type);
1664 }
1665 }
1666
1667 void validateAnnotationType(DiagnosticPosition pos, Type type) {
1668 if (type.isPrimitive()) return;
1669 if (types.isSameType(type, syms.stringType)) return;
1670 if ((type.tsym.flags() & Flags.ENUM) != 0) return;
1671 if ((type.tsym.flags() & Flags.ANNOTATION) != 0) return;
1672 if (types.lowerBound(type).tsym == syms.classType.tsym) return;
1673 if (types.isArray(type) && !types.isArray(types.elemtype(type))) {
1674 validateAnnotationType(pos, types.elemtype(type));
1675 return;
1676 }
1677 log.error(pos, "invalid.annotation.member.type");
1678 }
1679
1680 /**
1681 * "It is also a compile-time error if any method declared in an
1682 * annotation type has a signature that is override-equivalent to
1683 * that of any public or protected method declared in class Object
1684 * or in the interface annotation.Annotation."
1685 *
1686 * @jls3 9.6 Annotation Types
1687 */
1688 void validateAnnotationMethod(DiagnosticPosition pos, MethodSymbol m) {
1689 for (Type sup = syms.annotationType; sup.tag == CLASS; sup = types.supertype(sup)) {
1690 Scope s = sup.tsym.members();
1691 for (Scope.Entry e = s.lookup(m.name); e.scope != null; e = e.next()) {
1692 if (e.sym.kind == MTH &&
1693 (e.sym.flags() & (PUBLIC | PROTECTED)) != 0 &&
1694 types.overrideEquivalent(m.type, e.sym.type))
1695 log.error(pos, "intf.annotation.member.clash", e.sym, sup);
1696 }
1697 }
1698 }
1699
1700 /** Check the annotations of a symbol.
1701 */
1702 public void validateAnnotations(List<JCAnnotation> annotations, Symbol s) {
1703 if (skipAnnotations) return;
1704 for (JCAnnotation a : annotations)
1705 validateAnnotation(a, s);
1706 }
1707
1708 /** Check an annotation of a symbol.
1709 */
1710 public void validateAnnotation(JCAnnotation a, Symbol s) {
1711 validateAnnotation(a);
1712
1713 if (!annotationApplicable(a, s))
1714 log.error(a.pos(), "annotation.type.not.applicable");
1715
1716 if (a.annotationType.type.tsym == syms.overrideType.tsym) {
1717 if (!isOverrider(s))
1718 log.error(a.pos(), "method.does.not.override.superclass");
1719 }
1720 }
1721
1722 /** Is s a method symbol that overrides a method in a superclass? */
1723 boolean isOverrider(Symbol s) {
1724 if (s.kind != MTH || s.isStatic())
1725 return false;
1726 MethodSymbol m = (MethodSymbol)s;
1727 TypeSymbol owner = (TypeSymbol)m.owner;
1728 for (Type sup : types.closure(owner.type)) {
1729 if (sup == owner.type)
1730 continue; // skip "this"
1731 Scope scope = sup.tsym.members();
1732 for (Scope.Entry e = scope.lookup(m.name); e.scope != null; e = e.next()) {
1733 if (!e.sym.isStatic() && m.overrides(e.sym, owner, types, true))
1734 return true;
1735 }
1736 }
1737 return false;
1738 }
1739
1740 /** Is the annotation applicable to the symbol? */
1741 boolean annotationApplicable(JCAnnotation a, Symbol s) {
1742 Attribute.Compound atTarget =
1743 a.annotationType.type.tsym.attribute(syms.annotationTargetType.tsym);
1744 if (atTarget == null) return true;
1745 Attribute atValue = atTarget.member(names.value);
1746 if (!(atValue instanceof Attribute.Array)) return true; // error recovery
1747 Attribute.Array arr = (Attribute.Array) atValue;
1748 for (Attribute app : arr.values) {
1749 if (!(app instanceof Attribute.Enum)) return true; // recovery
1750 Attribute.Enum e = (Attribute.Enum) app;
1751 if (e.value.name == names.TYPE)
1752 { if (s.kind == TYP) return true; }
1753 else if (e.value.name == names.FIELD)
1754 { if (s.kind == VAR && s.owner.kind != MTH) return true; }
1755 else if (e.value.name == names.METHOD)
1756 { if (s.kind == MTH && !s.isConstructor()) return true; }
1757 else if (e.value.name == names.PARAMETER)
1758 { if (s.kind == VAR &&
1759 s.owner.kind == MTH &&
1760 (s.flags() & PARAMETER) != 0)
1761 return true;
1762 }
1763 else if (e.value.name == names.CONSTRUCTOR)
1764 { if (s.kind == MTH && s.isConstructor()) return true; }
1765 else if (e.value.name == names.LOCAL_VARIABLE)
1766 { if (s.kind == VAR && s.owner.kind == MTH &&
1767 (s.flags() & PARAMETER) == 0)
1768 return true;
1769 }
1770 else if (e.value.name == names.ANNOTATION_TYPE)
1771 { if (s.kind == TYP && (s.flags() & ANNOTATION) != 0)
1772 return true;
1773 }
1774 else if (e.value.name == names.PACKAGE)
1775 { if (s.kind == PCK) return true; }
1776 else
1777 return true; // recovery
1778 }
1779 return false;
1780 }
1781
1782 /** Check an annotation value.
1783 */
1784 public void validateAnnotation(JCAnnotation a) {
1785 if (a.type.isErroneous()) return;
1786
1787 // collect an inventory of the members
1788 Set<MethodSymbol> members = new HashSet<MethodSymbol>();
1789 for (Scope.Entry e = a.annotationType.type.tsym.members().elems;
1790 e != null;
1791 e = e.sibling)
1792 if (e.sym.kind == MTH)
1793 members.add((MethodSymbol) e.sym);
1794
1795 // count them off as they're annotated
1796 for (JCTree arg : a.args) {
1797 if (arg.getTag() != JCTree.ASSIGN) continue; // recovery
1798 JCAssign assign = (JCAssign) arg;
1799 Symbol m = TreeInfo.symbol(assign.lhs);
1800 if (m == null || m.type.isErroneous()) continue;
1801 if (!members.remove(m))
1802 log.error(arg.pos(), "duplicate.annotation.member.value",
1803 m.name, a.type);
1804 if (assign.rhs.getTag() == ANNOTATION)
1805 validateAnnotation((JCAnnotation)assign.rhs);
1806 }
1807
1808 // all the remaining ones better have default values
1809 for (MethodSymbol m : members)
1810 if (m.defaultValue == null && !m.type.isErroneous())
1811 log.error(a.pos(), "annotation.missing.default.value",
1812 a.type, m.name);
1813
1814 // special case: java.lang.annotation.Target must not have
1815 // repeated values in its value member
1816 if (a.annotationType.type.tsym != syms.annotationTargetType.tsym ||
1817 a.args.tail == null)
1818 return;
1819
1820 if (a.args.head.getTag() != JCTree.ASSIGN) return; // error recovery
1821 JCAssign assign = (JCAssign) a.args.head;
1822 Symbol m = TreeInfo.symbol(assign.lhs);
1823 if (m.name != names.value) return;
1824 JCTree rhs = assign.rhs;
1825 if (rhs.getTag() != JCTree.NEWARRAY) return;
1826 JCNewArray na = (JCNewArray) rhs;
1827 Set<Symbol> targets = new HashSet<Symbol>();
1828 for (JCTree elem : na.elems) {
1829 if (!targets.add(TreeInfo.symbol(elem))) {
1830 log.error(elem.pos(), "repeated.annotation.target");
1831 }
1832 }
1833 }
1834
1835 void checkDeprecatedAnnotation(DiagnosticPosition pos, Symbol s) {
1836 if (allowAnnotations &&
1837 lint.isEnabled(Lint.LintCategory.DEP_ANN) &&
1838 (s.flags() & DEPRECATED) != 0 &&
1839 !syms.deprecatedType.isErroneous() &&
1840 s.attribute(syms.deprecatedType.tsym) == null) {
1841 log.warning(pos, "missing.deprecated.annotation");
1842 }
1843 }
1844
1845 /* *************************************************************************
1846 * Check for recursive annotation elements.
1847 **************************************************************************/
1848
1849 /** Check for cycles in the graph of annotation elements.
1850 */
1851 void checkNonCyclicElements(JCClassDecl tree) {
1852 if ((tree.sym.flags_field & ANNOTATION) == 0) return;
1853 assert (tree.sym.flags_field & LOCKED) == 0;
1854 try {
1855 tree.sym.flags_field |= LOCKED;
1856 for (JCTree def : tree.defs) {
1857 if (def.getTag() != JCTree.METHODDEF) continue;
1858 JCMethodDecl meth = (JCMethodDecl)def;
1859 checkAnnotationResType(meth.pos(), meth.restype.type);
1860 }
1861 } finally {
1862 tree.sym.flags_field &= ~LOCKED;
1863 tree.sym.flags_field |= ACYCLIC_ANN;
1864 }
1865 }
1866
1867 void checkNonCyclicElementsInternal(DiagnosticPosition pos, TypeSymbol tsym) {
1868 if ((tsym.flags_field & ACYCLIC_ANN) != 0)
1869 return;
1870 if ((tsym.flags_field & LOCKED) != 0) {
1871 log.error(pos, "cyclic.annotation.element");
1872 return;
1873 }
1874 try {
1875 tsym.flags_field |= LOCKED;
1876 for (Scope.Entry e = tsym.members().elems; e != null; e = e.sibling) {
1877 Symbol s = e.sym;
1878 if (s.kind != Kinds.MTH)
1879 continue;
1880 checkAnnotationResType(pos, ((MethodSymbol)s).type.getReturnType());
1881 }
1882 } finally {
1883 tsym.flags_field &= ~LOCKED;
1884 tsym.flags_field |= ACYCLIC_ANN;
1885 }
1886 }
1887
1888 void checkAnnotationResType(DiagnosticPosition pos, Type type) {
1889 switch (type.tag) {
1890 case TypeTags.CLASS:
1891 if ((type.tsym.flags() & ANNOTATION) != 0)
1892 checkNonCyclicElementsInternal(pos, type.tsym);
1893 break;
1894 case TypeTags.ARRAY:
1895 checkAnnotationResType(pos, types.elemtype(type));
1896 break;
1897 default:
1898 break; // int etc
1899 }
1900 }
1901
1902 /* *************************************************************************
1903 * Check for cycles in the constructor call graph.
1904 **************************************************************************/
1905
1906 /** Check for cycles in the graph of constructors calling other
1907 * constructors.
1908 */
1909 void checkCyclicConstructors(JCClassDecl tree) {
1910 Map<Symbol,Symbol> callMap = new HashMap<Symbol, Symbol>();
1911
1912 // enter each constructor this-call into the map
1913 for (List<JCTree> l = tree.defs; l.nonEmpty(); l = l.tail) {
1914 JCMethodInvocation app = TreeInfo.firstConstructorCall(l.head);
1915 if (app == null) continue;
1916 JCMethodDecl meth = (JCMethodDecl) l.head;
1917 if (TreeInfo.name(app.meth) == names._this) {
1918 callMap.put(meth.sym, TreeInfo.symbol(app.meth));
1919 } else {
1920 meth.sym.flags_field |= ACYCLIC;
1921 }
1922 }
1923
1924 // Check for cycles in the map
1925 Symbol[] ctors = new Symbol[0];
1926 ctors = callMap.keySet().toArray(ctors);
1927 for (Symbol caller : ctors) {
1928 checkCyclicConstructor(tree, caller, callMap);
1929 }
1930 }
1931
1932 /** Look in the map to see if the given constructor is part of a
1933 * call cycle.
1934 */
1935 private void checkCyclicConstructor(JCClassDecl tree, Symbol ctor,
1936 Map<Symbol,Symbol> callMap) {
1937 if (ctor != null && (ctor.flags_field & ACYCLIC) == 0) {
1938 if ((ctor.flags_field & LOCKED) != 0) {
1939 log.error(TreeInfo.diagnosticPositionFor(ctor, tree),
1940 "recursive.ctor.invocation");
1941 } else {
1942 ctor.flags_field |= LOCKED;
1943 checkCyclicConstructor(tree, callMap.remove(ctor), callMap);
1944 ctor.flags_field &= ~LOCKED;
1945 }
1946 ctor.flags_field |= ACYCLIC;
1947 }
1948 }
1949
1950 /* *************************************************************************
1951 * Miscellaneous
1952 **************************************************************************/
1953
1954 /**
1955 * Return the opcode of the operator but emit an error if it is an
1956 * error.
1957 * @param pos position for error reporting.
1958 * @param operator an operator
1959 * @param tag a tree tag
1960 * @param left type of left hand side
1961 * @param right type of right hand side
1962 */
1963 int checkOperator(DiagnosticPosition pos,
1964 OperatorSymbol operator,
1965 int tag,
1966 Type left,
1967 Type right) {
1968 if (operator.opcode == ByteCodes.error) {
1969 log.error(pos,
1970 "operator.cant.be.applied",
1971 treeinfo.operatorName(tag),
1972 left + "," + right);
1973 }
1974 return operator.opcode;
1975 }
1976
1977
1978 /**
1979 * Check for division by integer constant zero
1980 * @param pos Position for error reporting.
1981 * @param operator The operator for the expression
1982 * @param operand The right hand operand for the expression
1983 */
1984 void checkDivZero(DiagnosticPosition pos, Symbol operator, Type operand) {
1985 if (operand.constValue() != null
1986 && lint.isEnabled(Lint.LintCategory.DIVZERO)
1987 && operand.tag <= LONG
1988 && ((Number) (operand.constValue())).longValue() == 0) {
1989 int opc = ((OperatorSymbol)operator).opcode;
1990 if (opc == ByteCodes.idiv || opc == ByteCodes.imod
1991 || opc == ByteCodes.ldiv || opc == ByteCodes.lmod) {
1992 log.warning(pos, "div.zero");
1993 }
1994 }
1995 }
1996
1997 /**
1998 * Check for empty statements after if
1999 */
2000 void checkEmptyIf(JCIf tree) {
2001 if (tree.thenpart.getTag() == JCTree.SKIP && tree.elsepart == null && lint.isEnabled(Lint.LintCategory.EMPTY))
2002 log.warning(tree.thenpart.pos(), "empty.if");
2003 }
2004
2005 /** Check that symbol is unique in given scope.
2006 * @param pos Position for error reporting.
2007 * @param sym The symbol.
2008 * @param s The scope.
2009 */
2010 boolean checkUnique(DiagnosticPosition pos, Symbol sym, Scope s) {
2011 if (sym.type.isErroneous())
2012 return true;
2013 if (sym.owner.name == names.any) return false;
2014 for (Scope.Entry e = s.lookup(sym.name); e.scope == s; e = e.next()) {
2015 if (sym != e.sym &&
2016 sym.kind == e.sym.kind &&
2017 sym.name != names.error &&
2018 (sym.kind != MTH || types.overrideEquivalent(sym.type, e.sym.type))) {
2019 if ((sym.flags() & VARARGS) != (e.sym.flags() & VARARGS))
2020 varargsDuplicateError(pos, sym, e.sym);
2021 else
2022 duplicateError(pos, e.sym);
2023 return false;
2024 }
2025 }
2026 return true;
2027 }
2028
2029 /** Check that single-type import is not already imported or top-level defined,
2030 * but make an exception for two single-type imports which denote the same type.
2031 * @param pos Position for error reporting.
2032 * @param sym The symbol.
2033 * @param s The scope
2034 */
2035 boolean checkUniqueImport(DiagnosticPosition pos, Symbol sym, Scope s) {
2036 return checkUniqueImport(pos, sym, s, false);
2037 }
2038
2039 /** Check that static single-type import is not already imported or top-level defined,
2040 * but make an exception for two single-type imports which denote the same type.
2041 * @param pos Position for error reporting.
2042 * @param sym The symbol.
2043 * @param s The scope
2044 * @param staticImport Whether or not this was a static import
2045 */
2046 boolean checkUniqueStaticImport(DiagnosticPosition pos, Symbol sym, Scope s) {
2047 return checkUniqueImport(pos, sym, s, true);
2048 }
2049
2050 /** Check that single-type import is not already imported or top-level defined,
2051 * but make an exception for two single-type imports which denote the same type.
2052 * @param pos Position for error reporting.
2053 * @param sym The symbol.
2054 * @param s The scope.
2055 * @param staticImport Whether or not this was a static import
2056 */
2057 private boolean checkUniqueImport(DiagnosticPosition pos, Symbol sym, Scope s, boolean staticImport) {
2058 for (Scope.Entry e = s.lookup(sym.name); e.scope != null; e = e.next()) {
2059 // is encountered class entered via a class declaration?
2060 boolean isClassDecl = e.scope == s;
2061 if ((isClassDecl || sym != e.sym) &&
2062 sym.kind == e.sym.kind &&
2063 sym.name != names.error) {
2064 if (!e.sym.type.isErroneous()) {
2065 String what = e.sym.toString();
2066 if (!isClassDecl) {
2067 if (staticImport)
2068 log.error(pos, "already.defined.static.single.import", what);
2069 else
2070 log.error(pos, "already.defined.single.import", what);
2071 }
2072 else if (sym != e.sym)
2073 log.error(pos, "already.defined.this.unit", what);
2074 }
2075 return false;
2076 }
2077 }
2078 return true;
2079 }
2080
2081 /** Check that a qualified name is in canonical form (for import decls).
2082 */
2083 public void checkCanonical(JCTree tree) {
2084 if (!isCanonical(tree))
2085 log.error(tree.pos(), "import.requires.canonical",
2086 TreeInfo.symbol(tree));
2087 }
2088 // where
2089 private boolean isCanonical(JCTree tree) {
2090 while (tree.getTag() == JCTree.SELECT) {
2091 JCFieldAccess s = (JCFieldAccess) tree;
2092 if (s.sym.owner != TreeInfo.symbol(s.selected))
2093 return false;
2094 tree = s.selected;
2095 }
2096 return true;
2097 }
2098
2099 private class ConversionWarner extends Warner {
2100 final String key;
2101 final Type found;
2102 final Type expected;
2103 public ConversionWarner(DiagnosticPosition pos, String key, Type found, Type expected) {
2104 super(pos);
2105 this.key = key;
2106 this.found = found;
2107 this.expected = expected;
2108 }
2109
2110 public void warnUnchecked() {
2111 boolean warned = this.warned;
2112 super.warnUnchecked();
2113 if (warned) return; // suppress redundant diagnostics
2114 Object problem = JCDiagnostic.fragment(key);
2115 Check.this.warnUnchecked(pos(), "prob.found.req", problem, found, expected);
2116 }
2117 }
2118
2119 public Warner castWarner(DiagnosticPosition pos, Type found, Type expected) {
2120 return new ConversionWarner(pos, "unchecked.cast.to.type", found, expected);
2121 }
2122
2123 public Warner convertWarner(DiagnosticPosition pos, Type found, Type expected) {
2124 return new ConversionWarner(pos, "unchecked.assign", found, expected);
2125 }
2126 }