generics: choose least bound symmetric (IDEA-57500)

java/java-psi-api/src/com/intellij/psi/GenericsUtil.java

@@ -150,7 +150,7 @@ public class GenericsUtil {
         if (type2 instanceof PsiWildcardType) {
           PsiWildcardType wild2 = (PsiWildcardType)type2;
           final PsiType bound2 = wild2.getBound();
-          if (bound2 == null) return wild1;
+          if (bound2 == null) return type2;
           if (wild1.isExtends() == wild2.isExtends()) {
             return wild1.isExtends() ?
                    PsiWildcardType.createExtends(manager, getLeastUpperBound(bound1, bound2, compared, manager)) :

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting7/ambiguousIDEA57500/pck/AmbiguousMethodCall.java

@@ -0,0 +1,14 @@
+package pck;
+
+interface I<T> {}
+interface A extends I<I<? extends String>>{}
+interface B extends I<I<?>>{}
+
+abstract class X {
+    abstract <T> T foo(T x, T y);
+
+    void bar(A x, B y){
+        foo(x, y);
+        foo(y, y);
+    }
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/AdvHighlightingJdk7Test.java

@@ -192,6 +192,10 @@ public class AdvHighlightingJdk7Test extends DaemonAnalyzerTestCase {
     doTestAmbiguous();
   }
 
+  public void testAmbiguousIDEA57500() throws Exception {
+    doTestAmbiguous();
+  }
+
   public void testAmbiguousMethodsFromSameClassAccess() throws Exception {
     doTestAmbiguous();
   }