Render FQ name of default package as "root package" in OverloadResolver

compiler/frontend/src/org/jetbrains/jet/lang/resolve/OverloadResolver.java

@@ -106,7 +106,9 @@ public class OverloadResolver {
         }
 
         for (Map.Entry<FqNameUnsafe, Collection<CallableMemberDescriptor>> e : functionsByName.entrySet()) {
-            checkOverloadsWithSameName(e.getValue(), e.getKey().parent().asString());
+            // TODO: don't render FQ name here, extract this logic to somewhere
+            FqNameUnsafe fqName = e.getKey().parent();
+            checkOverloadsWithSameName(e.getValue(), fqName.isRoot() ? "root package" : fqName.asString());
         }
     }
 

idea/testData/diagnosticMessage/conflictingOverloadsDefaultPackage.kt

@@ -0,0 +1,6 @@
+// !DIAGNOSTICS_NUMBER: 2
+// !DIAGNOSTICS: CONFLICTING_OVERLOADS
+// !MESSAGE_TYPE: TEXT
+
+fun foo(x: Int) = x
+fun foo(y: Int) = y

idea/testData/diagnosticMessage/conflictingOverloadsDefaultPackage1.txt

@@ -0,0 +1,2 @@
+<!-- conflictingOverloadsDefaultPackage1 -->
+'internal fun foo(x: kotlin.Int): kotlin.Int' is already defined in root package

idea/testData/diagnosticMessage/conflictingOverloadsDefaultPackage2.txt

@@ -0,0 +1,2 @@
+<!-- conflictingOverloadsDefaultPackage2 -->
+'internal fun foo(y: kotlin.Int): kotlin.Int' is already defined in root package

idea/tests/org/jetbrains/jet/plugin/highlighter/DiagnosticMessageTestGenerated.java

@@ -41,6 +41,11 @@ public class DiagnosticMessageTestGenerated extends AbstractDiagnosticMessageTes
         doTest("idea/testData/diagnosticMessage/conflictingOverloadsClass.kt");
     }
     
+    @TestMetadata("conflictingOverloadsDefaultPackage.kt")
+    public void testConflictingOverloadsDefaultPackage() throws Exception {
+        doTest("idea/testData/diagnosticMessage/conflictingOverloadsDefaultPackage.kt");
+    }
+    
     @TestMetadata("conflictingSubstitutions.kt")
     public void testConflictingSubstitutions() throws Exception {
         doTest("idea/testData/diagnosticMessage/conflictingSubstitutions.kt");