diff -r 0524f786d7e8 -r 77352397867a src/share/classes/com/sun/tools/javac/comp/Infer.java --- a/src/share/classes/com/sun/tools/javac/comp/Infer.java Fri Apr 18 23:50:41 2014 +0100 +++ b/src/share/classes/com/sun/tools/javac/comp/Infer.java Fri Apr 18 23:58:05 2014 +0100 @@ -516,6 +516,32 @@ /** max number of incorporation rounds */ static final int MAX_INCORPORATION_STEPS = 100; + /* If for two types t and s there is a least upper bound that is a + * parameterized type G, then there exists a supertype of 't' of the form + * G and a supertype of 's' of the form G + * which will be returned by this method. If no such supertypes exists then + * null is returned. + * + * As an example for the following input: + * + * t = java.util.ArrayList + * s = java.util.List + * + * we get this ouput: + * + * Pair[java.util.List,java.util.List] + */ + private Pair getParameterizedSupers(Type t, Type s) { + Type lubResult = types.lub(t, s); + if (lubResult == syms.errType || lubResult == syms.botType || + !lubResult.isParameterized()) { + return null; + } + Type asSuperOfT = types.asSuper(t, lubResult.tsym); + Type asSuperOfS = types.asSuper(s, lubResult.tsym); + return new Pair<>(asSuperOfT, asSuperOfS); + } + /** * This enumeration defines an entry point for doing inference variable * bound incorporation - it can be used to inject custom incorporation @@ -651,6 +677,53 @@ } }, /** + * Given a bound set containing {@code alpha <: P} and + * {@code alpha <: P} where P is a parameterized type, + * perform {@code T = S} (which could lead to new bounds). + */ + CROSS_UPPER_UPPER() { + @Override + public void apply(UndetVar uv, InferenceContext inferenceContext, Warner warn) { + Infer infer = inferenceContext.infer(); + List boundList = uv.getBounds(InferenceBound.UPPER); + List boundListTail = boundList.tail; + while (boundList.nonEmpty()) { + List tmpTail = boundListTail; + while (tmpTail.nonEmpty()) { + Type b1 = boundList.head; + Type b2 = tmpTail.head; + if (b1 != b2) { + Pair commonSupers = infer.getParameterizedSupers(b1, b2); + if (commonSupers != null) { + List allParamsSuperBound1 = commonSupers.fst.allparams(); + List allParamsSuperBound2 = commonSupers.snd.allparams(); + while (allParamsSuperBound1.nonEmpty() && allParamsSuperBound2.nonEmpty()) { + //traverse the list of all params comparing them + if (!allParamsSuperBound1.head.hasTag(WILDCARD) && + !allParamsSuperBound2.head.hasTag(WILDCARD)) { + isSameType(inferenceContext.asUndetVar(allParamsSuperBound1.head), + inferenceContext.asUndetVar(allParamsSuperBound2.head), infer); + } + allParamsSuperBound1 = allParamsSuperBound1.tail; + allParamsSuperBound2 = allParamsSuperBound2.tail; + } + Assert.check(allParamsSuperBound1.isEmpty() && allParamsSuperBound2.isEmpty()); + } + } + tmpTail = tmpTail.tail; + } + boundList = boundList.tail; + boundListTail = boundList.tail; + } + } + + @Override + boolean accepts(UndetVar uv, InferenceContext inferenceContext) { + return !uv.isCaptured() && + uv.getBounds(InferenceBound.UPPER).nonEmpty(); + } + }, + /** * Given a bound set containing {@code alpha == S} and {@code alpha == T} * perform {@code S == T} (which could lead to new bounds). */