8055963: Inference failure with nested invocation
Summary: Revise heuristics to force eager instantiation of return inference vars
Reviewed-by: vromero
--- a/langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Infer.java Fri Sep 12 17:05:18 2014 -0700
+++ b/langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Infer.java Mon Sep 15 12:43:35 2014 +0100
@@ -358,11 +358,9 @@
for (Type aLowerBound : from.getBounds(InferenceBound.LOWER)) {
for (Type anotherLowerBound : from.getBounds(InferenceBound.LOWER)) {
if (aLowerBound != anotherLowerBound &&
- commonSuperWithDiffParameterization(aLowerBound, anotherLowerBound)) {
- /* self comment check if any lower bound may be and undetVar,
- * in that case the result of this call may be a false positive.
- * Should this be restricted to non free types?
- */
+ !inferenceContext.free(aLowerBound) &&
+ !inferenceContext.free(anotherLowerBound) &&
+ commonSuperWithDiffParameterization(aLowerBound, anotherLowerBound)) {
return generateReferenceToTargetConstraint(tree, from, to,
resultInfo, inferenceContext);
}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/inference/8055963/T8055963.java Mon Sep 15 12:43:35 2014 +0100
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8055963
+ * @summary Inference failure with nested invocation
+ * @compile T8055963.java
+ */
+class T8055963 {
+
+ static class C<T> {}
+
+ <T> T choose(T first, T second) { return null; }
+
+ void test() {
+ C<String> cs = choose(new C<String>(), new C<>());
+ }
+}