find functional interface on arrow/dbl column (IDEA-122033)

java/java-impl/src/com/intellij/codeInsight/TargetElementUtil.java

@@ -99,6 +99,15 @@ public class TargetElementUtil extends TargetElementUtilBase {
       if (ref instanceof PsiJavaReference) {
         refElement = ((PsiJavaReference)ref).advancedResolve(true).getElement();
       }
+      else if (ref == null) {
+        final PsiElement element = file.findElementAt(offset);
+        if (element != null) {
+          final PsiElement parent = element.getParent();
+          if (parent instanceof PsiFunctionalExpression) {
+            refElement = PsiUtil.resolveClassInType(((PsiFunctionalExpression)parent).getFunctionalInterfaceType());
+          }
+        } 
+      }
     }
 
     if (refElement != null) {

java/java-tests/testSrc/com/intellij/navigation/ShowImplementationHandlerTest.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2000-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.intellij.navigation;
+
+import com.intellij.codeInsight.TargetElementUtilBase;
+import com.intellij.psi.CommonClassNames;
+import com.intellij.psi.PsiClass;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiFile;
+import com.intellij.testFramework.fixtures.JavaCodeInsightFixtureTestCase;
+
+public class ShowImplementationHandlerTest extends JavaCodeInsightFixtureTestCase {
+
+  public void testMultipleImplsFromAbstractCall() throws Throwable {
+    PsiFile file = myFixture.addFileToProject("Foo.java", "public abstract class Hello {" +
+                                                          "    {" +
+                                                          "        Runnable r = () <caret>-> {};\n" +
+                                                          "    }\n" +
+                                                          "}\n" +
+                                                          "\n");
+    myFixture.configureFromExistingVirtualFile(file.getVirtualFile());
+
+    final PsiElement element =
+      TargetElementUtilBase.findTargetElement(myFixture.getEditor(), TargetElementUtilBase.getInstance().getAllAccepted());
+    assertTrue(element instanceof PsiClass);
+    final String qualifiedName = ((PsiClass)element).getQualifiedName();
+    assertEquals(CommonClassNames.JAVA_LANG_RUNNABLE, qualifiedName);
+  }
+
+}