1.1 --- a/src/share/classes/com/sun/tools/javac/comp/Infer.java Fri Apr 18 23:50:41 2014 +0100
1.2 +++ b/src/share/classes/com/sun/tools/javac/comp/Infer.java Fri Apr 18 23:58:05 2014 +0100
1.3 @@ -516,6 +516,32 @@
1.4 /** max number of incorporation rounds */
1.5 static final int MAX_INCORPORATION_STEPS = 100;
1.6
1.7 + /* If for two types t and s there is a least upper bound that is a
1.8 + * parameterized type G, then there exists a supertype of 't' of the form
1.9 + * G<T1, ..., Tn> and a supertype of 's' of the form G<S1, ..., Sn>
1.10 + * which will be returned by this method. If no such supertypes exists then
1.11 + * null is returned.
1.12 + *
1.13 + * As an example for the following input:
1.14 + *
1.15 + * t = java.util.ArrayList<java.lang.String>
1.16 + * s = java.util.List<T>
1.17 + *
1.18 + * we get this ouput:
1.19 + *
1.20 + * Pair[java.util.List<java.lang.String>,java.util.List<T>]
1.21 + */
1.22 + private Pair<Type, Type> getParameterizedSupers(Type t, Type s) {
1.23 + Type lubResult = types.lub(t, s);
1.24 + if (lubResult == syms.errType || lubResult == syms.botType ||
1.25 + !lubResult.isParameterized()) {
1.26 + return null;
1.27 + }
1.28 + Type asSuperOfT = types.asSuper(t, lubResult.tsym);
1.29 + Type asSuperOfS = types.asSuper(s, lubResult.tsym);
1.30 + return new Pair<>(asSuperOfT, asSuperOfS);
1.31 + }
1.32 +
1.33 /**
1.34 * This enumeration defines an entry point for doing inference variable
1.35 * bound incorporation - it can be used to inject custom incorporation
1.36 @@ -651,6 +677,53 @@
1.37 }
1.38 },
1.39 /**
1.40 + * Given a bound set containing {@code alpha <: P<T>} and
1.41 + * {@code alpha <: P<S>} where P is a parameterized type,
1.42 + * perform {@code T = S} (which could lead to new bounds).
1.43 + */
1.44 + CROSS_UPPER_UPPER() {
1.45 + @Override
1.46 + public void apply(UndetVar uv, InferenceContext inferenceContext, Warner warn) {
1.47 + Infer infer = inferenceContext.infer();
1.48 + List<Type> boundList = uv.getBounds(InferenceBound.UPPER);
1.49 + List<Type> boundListTail = boundList.tail;
1.50 + while (boundList.nonEmpty()) {
1.51 + List<Type> tmpTail = boundListTail;
1.52 + while (tmpTail.nonEmpty()) {
1.53 + Type b1 = boundList.head;
1.54 + Type b2 = tmpTail.head;
1.55 + if (b1 != b2) {
1.56 + Pair<Type, Type> commonSupers = infer.getParameterizedSupers(b1, b2);
1.57 + if (commonSupers != null) {
1.58 + List<Type> allParamsSuperBound1 = commonSupers.fst.allparams();
1.59 + List<Type> allParamsSuperBound2 = commonSupers.snd.allparams();
1.60 + while (allParamsSuperBound1.nonEmpty() && allParamsSuperBound2.nonEmpty()) {
1.61 + //traverse the list of all params comparing them
1.62 + if (!allParamsSuperBound1.head.hasTag(WILDCARD) &&
1.63 + !allParamsSuperBound2.head.hasTag(WILDCARD)) {
1.64 + isSameType(inferenceContext.asUndetVar(allParamsSuperBound1.head),
1.65 + inferenceContext.asUndetVar(allParamsSuperBound2.head), infer);
1.66 + }
1.67 + allParamsSuperBound1 = allParamsSuperBound1.tail;
1.68 + allParamsSuperBound2 = allParamsSuperBound2.tail;
1.69 + }
1.70 + Assert.check(allParamsSuperBound1.isEmpty() && allParamsSuperBound2.isEmpty());
1.71 + }
1.72 + }
1.73 + tmpTail = tmpTail.tail;
1.74 + }
1.75 + boundList = boundList.tail;
1.76 + boundListTail = boundList.tail;
1.77 + }
1.78 + }
1.79 +
1.80 + @Override
1.81 + boolean accepts(UndetVar uv, InferenceContext inferenceContext) {
1.82 + return !uv.isCaptured() &&
1.83 + uv.getBounds(InferenceBound.UPPER).nonEmpty();
1.84 + }
1.85 + },
1.86 + /**
1.87 * Given a bound set containing {@code alpha == S} and {@code alpha == T}
1.88 * perform {@code S == T} (which could lead to new bounds).
1.89 */
