8024947: javac should issue the potentially ambiguous overload warning only where the problem appears
Reviewed-by: jjg
--- a/langtools/src/share/classes/com/sun/tools/javac/comp/Check.java Tue Oct 15 19:36:45 2013 +0100
+++ b/langtools/src/share/classes/com/sun/tools/javac/comp/Check.java Tue Oct 15 21:02:21 2013 +0100
@@ -2399,13 +2399,28 @@
ClashFilter cf = new ClashFilter(site);
//for each method m1 that is overridden (directly or indirectly)
//by method 'sym' in 'site'...
+
+ List<MethodSymbol> potentiallyAmbiguousList = List.nil();
+ boolean overridesAny = false;
for (Symbol m1 : types.membersClosure(site, false).getElementsByName(sym.name, cf)) {
- if (!sym.overrides(m1, site.tsym, types, false)) {
- checkPotentiallyAmbiguousOverloads(pos, site, sym, (MethodSymbol)m1);
- continue;
- }
- //...check each method m2 that is a member of 'site'
- for (Symbol m2 : types.membersClosure(site, false).getElementsByName(sym.name, cf)) {
+ if (!sym.overrides(m1, site.tsym, types, false)) {
+ if (m1 == sym) {
+ continue;
+ }
+
+ if (!overridesAny) {
+ potentiallyAmbiguousList = potentiallyAmbiguousList.prepend((MethodSymbol)m1);
+ }
+ continue;
+ }
+
+ if (m1 != sym) {
+ overridesAny = true;
+ potentiallyAmbiguousList = List.nil();
+ }
+
+ //...check each method m2 that is a member of 'site'
+ for (Symbol m2 : types.membersClosure(site, false).getElementsByName(sym.name, cf)) {
if (m2 == m1) continue;
//if (i) the signature of 'sym' is not a subsignature of m1 (seen as
//a member of 'site') and (ii) m1 has the same erasure as m2, issue an error
@@ -2424,10 +2439,14 @@
}
}
}
+
+ if (!overridesAny) {
+ for (MethodSymbol m: potentiallyAmbiguousList) {
+ checkPotentiallyAmbiguousOverloads(pos, site, sym, m);
+ }
+ }
}
-
-
/** Check that all static methods accessible from 'site' are
* mutually compatible (JLS 8.4.8).
*
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/lambda/T8024947/PotentiallyAmbiguousWarningTest.java Tue Oct 15 21:02:21 2013 +0100
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2013, 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.
+ *
+ * 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 8024947
+ * @summary javac should issue the potentially ambiguous overload warning only
+ * where the problem appears
+ * @compile/fail/ref=PotentiallyAmbiguousWarningTest.out -XDrawDiagnostics -Werror -Xlint:overloads PotentiallyAmbiguousWarningTest.java
+ * @compile PotentiallyAmbiguousWarningTest.java
+ */
+
+import java.util.function.*;
+
+public interface PotentiallyAmbiguousWarningTest {
+
+ //a warning should be fired
+ interface I1 {
+ void foo(Consumer<Integer> c);
+ void foo(IntConsumer c);
+ }
+
+ //a warning should be fired
+ class C1 {
+ void foo(Consumer<Integer> c) { }
+ void foo(IntConsumer c) { }
+ }
+
+ interface I2 {
+ void foo(Consumer<Integer> c);
+ }
+
+ //a warning should be fired, J1 is provoking the issue
+ interface J1 extends I2 {
+ void foo(IntConsumer c);
+ }
+
+ //no warning here, the issue is introduced in I1
+ interface I3 extends I1 {}
+
+ //no warning here, the issue is introduced in I1. I4 is just overriding an existing method
+ interface I4 extends I1 {
+ void foo(IntConsumer c);
+ }
+
+ class C2 {
+ void foo(Consumer<Integer> c) { }
+ }
+
+ //a warning should be fired, D1 is provoking the issue
+ class D1 extends C2 {
+ void foo(IntConsumer c) { }
+ }
+
+ //a warning should be fired, C3 is provoking the issue
+ class C3 implements I2 {
+ public void foo(Consumer<Integer> c) { }
+ public void foo(IntConsumer c) { }
+ }
+
+ //no warning here, the issue is introduced in C1
+ class C4 extends C1 {}
+
+ //no warning here, the issue is introduced in C1. C5 is just overriding an existing method
+ class C5 extends C1 {
+ void foo(IntConsumer c) {}
+ }
+
+ interface I5<T> {
+ void foo(T c);
+ }
+
+ //a warning should be fired, J2 is provoking the issue
+ interface J2 extends I5<IntConsumer> {
+ void foo(Consumer<Integer> c);
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/lambda/T8024947/PotentiallyAmbiguousWarningTest.out Tue Oct 15 21:02:21 2013 +0100
@@ -0,0 +1,9 @@
+PotentiallyAmbiguousWarningTest.java:39:14: compiler.warn.potentially.ambiguous.overload: foo(java.util.function.Consumer<java.lang.Integer>), PotentiallyAmbiguousWarningTest.I1, foo(java.util.function.IntConsumer), PotentiallyAmbiguousWarningTest.I1
+PotentiallyAmbiguousWarningTest.java:45:14: compiler.warn.potentially.ambiguous.overload: foo(java.util.function.Consumer<java.lang.Integer>), PotentiallyAmbiguousWarningTest.C1, foo(java.util.function.IntConsumer), PotentiallyAmbiguousWarningTest.C1
+PotentiallyAmbiguousWarningTest.java:55:14: compiler.warn.potentially.ambiguous.overload: foo(java.util.function.IntConsumer), PotentiallyAmbiguousWarningTest.J1, foo(java.util.function.Consumer<java.lang.Integer>), PotentiallyAmbiguousWarningTest.I2
+PotentiallyAmbiguousWarningTest.java:72:14: compiler.warn.potentially.ambiguous.overload: foo(java.util.function.IntConsumer), PotentiallyAmbiguousWarningTest.D1, foo(java.util.function.Consumer<java.lang.Integer>), PotentiallyAmbiguousWarningTest.C2
+PotentiallyAmbiguousWarningTest.java:78:21: compiler.warn.potentially.ambiguous.overload: foo(java.util.function.IntConsumer), PotentiallyAmbiguousWarningTest.C3, foo(java.util.function.Consumer<java.lang.Integer>), PotentiallyAmbiguousWarningTest.C3
+PotentiallyAmbiguousWarningTest.java:95:14: compiler.warn.potentially.ambiguous.overload: foo(java.util.function.Consumer<java.lang.Integer>), PotentiallyAmbiguousWarningTest.J2, foo(T), PotentiallyAmbiguousWarningTest.I5
+- compiler.err.warnings.and.werror
+1 error
+6 warnings