KT-1254 "Implement members" gives strange result when implementing a method returning function type

#KT-1254 fixed

idea/src/org/jetbrains/jet/plugin/codeInsight/OverrideImplementMethodsHandler.java

@@ -162,7 +162,7 @@ public abstract class OverrideImplementMethodsHandler implements LanguageCodeIns
         final JetStandardLibrary stdlib = JetStandardLibrary.getInstance();
 
         if (returnType != null && !stdlib.getTuple0Type().equals(returnType)) {
-            bodyBuilder.append(" : ").append(returnType.toString());
+            bodyBuilder.append(" : ").append(DescriptorRenderer.COMPACT.renderTypeWithShortNames(returnType));
             ImportInsertHelper.addImportDirectiveIfNeeded(returnType, file);
         }
 

idea/testData/codeInsight/overrideImplement/functionMethod.kt

@@ -0,0 +1,8 @@
+// From KT-1254
+trait T {
+    fun Foo() : (String) -> Unit
+}
+
+class C : T {
+  <caret>
+}

idea/testData/codeInsight/overrideImplement/functionMethod.kt.after

@@ -0,0 +1,11 @@
+// From KT-1254
+trait T {
+    fun Foo() : (String) -> Unit
+}
+
+class C : T {
+
+    override fun Foo() : (String) -> Unit {
+        throw UnsupportedOperationException()
+    }
+}

idea/tests/org/jetbrains/jet/plugin/codeInsight/OverrideImplementTest.java

@@ -49,6 +49,10 @@ public class OverrideImplementTest extends LightCodeInsightFixtureTestCase {
         myFixture.setTestDataPath(PluginTestCaseBase.getTestDataPathBase() + "/codeInsight/overrideImplement");
     }
 
+    public void testFunctionMethod() {
+        doFileTest();
+    }
+
     public void testFunctionProperty() {
         doFileTest();
     }