Test for reporting clashes with multiple delegated methods

Verifies that the order in which traits are inherited is irrelevant

compiler/frontend/src/org/jetbrains/jet/lang/resolve/DelegationResolver.java

@@ -219,6 +219,7 @@ public final class DelegationResolver<T extends CallableMemberDescriptor> {
     }
 
     private static boolean haveSameSignatures(@NotNull CallableDescriptor memberOne, @NotNull CallableDescriptor memberTwo) {
+        //isOverridableBy ignores return types
         return OverridingUtil.isOverridableBy(memberOne, memberTwo).getResult() == OVERRIDABLE;
     }
 

compiler/testData/diagnostics/tests/Delegation_ClashingFunctions.kt

@@ -0,0 +1,17 @@
+trait One {
+    public fun foo(): Any?
+}
+trait Two {
+    public fun foo(): String?
+}
+
+trait Three {
+    public fun foo(): String
+}
+
+class <!MANY_IMPL_MEMBER_NOT_IMPLEMENTED, MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>Test123<!>(val v1: One, val v2: Two, val v3: Three) : One by v1, Two by v2, Three by v3 { }
+class <!MANY_IMPL_MEMBER_NOT_IMPLEMENTED, MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>Test132<!>(val v1: One, val v2: Two, val v3: Three) : One by v1, Three by v3, Two by v2 { }
+class <!MANY_IMPL_MEMBER_NOT_IMPLEMENTED, MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>Test312<!>(val v1: One, val v2: Two, val v3: Three) : Three by v3, One by v1, Two by v2 { }
+class <!MANY_IMPL_MEMBER_NOT_IMPLEMENTED, MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>Test321<!>(val v1: One, val v2: Two, val v3: Three) : Three by v3, Two by v2, One by v1 { }
+class <!MANY_IMPL_MEMBER_NOT_IMPLEMENTED, MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>Test231<!>(val v1: One, val v2: Two, val v3: Three) : Two by v2, Three by v3, One by v1 { }
+class <!MANY_IMPL_MEMBER_NOT_IMPLEMENTED, MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>Test213<!>(val v1: One, val v2: Two, val v3: Three) : Two by v2, One by v1, Three by v3 { }

compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java

@@ -194,6 +194,11 @@ public class JetDiagnosticsTestGenerated extends AbstractDiagnosticsTestWithEage
             doTest("compiler/testData/diagnostics/tests/DelegationToJavaIface.kt");
         }
         
+        @TestMetadata("Delegation_ClashingFunctions.kt")
+        public void testDelegation_ClashingFunctions() throws Exception {
+            doTest("compiler/testData/diagnostics/tests/Delegation_ClashingFunctions.kt");
+        }
+        
         @TestMetadata("Delegation_Hierarchy.kt")
         public void testDelegation_Hierarchy() throws Exception {
             doTest("compiler/testData/diagnostics/tests/Delegation_Hierarchy.kt");