method refs: search for potentially applicable members in supers (IDEA-121737)

java/java-psi-impl/src/com/intellij/psi/impl/source/tree/java/PsiMethodReferenceExpressionImpl.java

@@ -161,7 +161,7 @@ public class PsiMethodReferenceExpressionImpl extends PsiReferenceExpressionBase
     if (containingClass != null) {
       PsiMethod[] methods = null;
       if (element instanceof PsiIdentifier) {
-        methods = containingClass.findMethodsByName(element.getText(), false);
+        methods = containingClass.findMethodsByName(element.getText(), true);
       }
       else if (isConstructor()) {
         final PsiElementFactory factory = JavaPsiFacade.getElementFactory(getProject());

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/SuperClassPotentiallyApplicableMembers.java

@@ -0,0 +1,39 @@
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+interface Base {
+  int getInt(String a);
+  int getInt();
+
+  void foo();
+}
+
+abstract class ABase implements Base {
+  @Override
+  public int getInt(String a) {
+    return 0;
+  }
+
+  @Override
+  public int getInt() {
+    return 0;
+  }
+}
+
+class Impl extends ABase {
+  @Override
+  public int getInt() {
+    return 0;
+  }
+
+  @Override
+  public void foo() {
+    List<String> strs = Arrays.asList("one", "two");
+
+    List<Integer> withMethodRef = strs
+      .stream()
+      .map(this::getInt)
+      .collect( Collectors.toList());
+  }
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/NewMethodRefHighlightingTest.java

@@ -181,6 +181,10 @@ public class NewMethodRefHighlightingTest extends LightDaemonAnalyzerTestCase {
     doTest();
   }
 
+  public void testSuperClassPotentiallyApplicableMembers() throws Exception {
+    doTest();
+  }
+
   private void doTest() {
     doTest(false);
   }