6938454: Unable to determine generic type in program that compiles under Java 6
Summary: a redundant dubtyping check causes spurious inference failure
Reviewed-by: jjg
--- a/langtools/src/share/classes/com/sun/tools/javac/comp/Attr.java Tue Jul 27 11:52:11 2010 -0700
+++ b/langtools/src/share/classes/com/sun/tools/javac/comp/Attr.java Thu Jul 29 15:56:25 2010 +0100
@@ -1694,8 +1694,22 @@
//if the type of the instance creation expression is an interface
//skip the method resolution step (JLS 15.12.2.7). The type to be
//inferred is of the kind <X1,X2, ... Xn>C<X1,X2, ... Xn>
- clazztype = new ForAll(clazztype.tsym.type.allparams(),
- clazztype.tsym.type);
+ clazztype = new ForAll(clazztype.tsym.type.allparams(), clazztype.tsym.type) {
+ @Override
+ public List<Type> getConstraints(TypeVar tv, ConstraintKind ck) {
+ switch (ck) {
+ case EXTENDS: return types.getBounds(tv);
+ default: return List.nil();
+ }
+ }
+ @Override
+ public Type inst(List<Type> inferred, Types types) throws Infer.NoInstanceException {
+ // check that inferred bounds conform to their bounds
+ infer.checkWithinBounds(tvars,
+ types.subst(tvars, tvars, inferred), Warner.noWarnings);
+ return super.inst(inferred, types);
+ }
+ };
} else {
//if the type of the instance creation expression is a class type
//apply method resolution inference (JLS 15.12.2.7). The return type
--- a/langtools/src/share/classes/com/sun/tools/javac/comp/Infer.java Tue Jul 27 11:52:11 2010 -0700
+++ b/langtools/src/share/classes/com/sun/tools/javac/comp/Infer.java Thu Jul 29 15:56:25 2010 +0100
@@ -256,7 +256,7 @@
UndetVar uv = (UndetVar) l.head;
TypeVar tv = (TypeVar)uv.qtype;
ListBuffer<Type> hibounds = new ListBuffer<Type>();
- for (Type t : that.getConstraints(tv, ConstraintKind.EXTENDS).prependList(types.getBounds(tv))) {
+ for (Type t : that.getConstraints(tv, ConstraintKind.EXTENDS)) {
if (!t.containsSome(that.tvars) && t.tag != BOT) {
hibounds.append(t);
}
@@ -280,7 +280,6 @@
// check bounds
List<Type> targs = Type.map(undetvars, getInstFun);
targs = types.subst(targs, that.tvars, targs);
- checkWithinBounds(that.tvars, targs, warn);
return chk.checkType(warn.pos(), that.inst(targs, types), to);
}
@@ -398,7 +397,7 @@
UndetVar uv = (UndetVar)t;
if (uv.qtype == tv) {
switch (ck) {
- case EXTENDS: return uv.hibounds;
+ case EXTENDS: return uv.hibounds.appendList(types.subst(types.getBounds(tv), all_tvars, inferredTypes));
case SUPER: return uv.lobounds;
case EQUAL: return uv.inst != null ? List.of(uv.inst) : List.<Type>nil();
}
@@ -458,7 +457,7 @@
/** check that type parameters are within their bounds.
*/
- private void checkWithinBounds(List<Type> tvars,
+ void checkWithinBounds(List<Type> tvars,
List<Type> arguments,
Warner warn)
throws InvalidInstanceException {
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/inference/6938454/T6938454a.java Thu Jul 29 15:56:25 2010 +0100
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2010 Sun Microsystems, Inc. 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.
+ *
+ * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+ * @test
+ * @bug 6938454
+ *
+ * @summary Unable to determine generic type in program that compiles under Java 6
+ * @author mcimadamore
+ * @compile T6938454a.java
+ *
+ */
+
+class T6938454a {
+
+ static abstract class A { }
+
+ static class B extends A { }
+
+ B getB(B b) {
+ return makeA(b);
+ }
+
+ <X extends A, Y extends X> Y makeA(X x) {
+ return (Y)new B();
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/inference/6938454/T6938454b.java Thu Jul 29 15:56:25 2010 +0100
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2010 Sun Microsystems, Inc. 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.
+ *
+ * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+import java.util.List;
+
+/*
+ * @test
+ * @bug 6938454
+ *
+ * @summary Unable to determine generic type in program that compiles under Java 6
+ * @author mcimadamore
+ * @compile T6938454b.java
+ *
+ */
+
+class T6938454b {
+
+ static interface A {}
+ static interface B extends A {}
+ static class C implements B {}
+
+ <T, R extends T, S extends R> List<R> m(List<T> l, S s) {
+ return null;
+ }
+
+ List<B> test(List<A> la) {
+ return m(la, new C());
+ }
+}