show warning on type parameter declaration if it lead to multiple methods with same erasure (java7 only)

java/java-impl/src/com/intellij/codeInsight/daemon/impl/analysis/GenericsHighlightUtil.java

@@ -372,6 +372,7 @@ public class GenericsHighlightUtil {
     }
   }
 
+  @Nullable
   public static HighlightInfo checkElementInTypeParameterExtendsList(PsiReferenceList referenceList, JavaResolveResult resolveResult, PsiElement element) {
     PsiClass aClass = (PsiClass)referenceList.getParent();
     final PsiJavaCodeReferenceElement[] referenceElements = referenceList.getReferenceElements();
@@ -393,6 +394,11 @@ public class GenericsHighlightUtil {
       IntentionAction fix = QUICK_FIX_FACTORY.createExtendsListFix(aClass, type, false);
       QuickFixAction.registerQuickFixAction(errorResult, fix, null);
     }
+    if (errorResult == null && JavaVersionService.getInstance().isAtLeast(referenceList, JavaSdkVersion.JDK_1_7) && 
+        referenceElements.length > 1) {
+      //todo suppress erased methods which come from the same class
+      return checkOverrideEquivalentMethods(aClass);
+    }
     return errorResult;
   }
   public static HighlightInfo checkInterfaceMultipleInheritance(PsiClass aClass) {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting7/ambiguousMultipleTypeParamExtends1/pck/AmbiguousMethodCall.java

@@ -9,7 +9,7 @@ interface IB{
     <T> void foo(A<T> x);
 }
 class C {
-    <T extends IA & IB> void bar(T x, A<String> y){
+    <<error descr="'foo(A<T>)' in 'pck.IB' clashes with 'foo(A<?>)' in 'pck.IA'; both methods have same erasure, yet neither overrides the other"></error>T extends IA & IB> void bar(T x, A<String> y){
         x.foo<error descr="Ambiguous method call: both 'IA.foo(A<?>)' and 'IB.foo(A<String>)' match">(y)</error>;
     }
 }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting7/ambiguousMultipleTypeParamExtends2/pck/AmbiguousMethodCall.java

@@ -9,7 +9,7 @@ interface IB{
     <T> void foo(A<? super A<T>> x);
 }
 class C {
-    <T extends IB & IA> void bar(T x, A<A<String>> y){
+    <<error descr="'foo(A<A<T>>)' in 'pck.IA' clashes with 'foo(A<? super A<T>>)' in 'pck.IB'; both methods have same erasure, yet neither overrides the other"></error>T extends IB & IA> void bar(T x, A<A<String>> y){
         x.foo(y);
     }
 }