 -        "of the property it overrides from interface {1}\n" +
 -        "original: {2}\n" +
 -        "override: {3}");
--
+ 
    static final DiagnosticGroup ALL_DIAGNOSTICS = new DiagnosticGroup(
        INVALID_CAST,
-       TYPE_MISMATCH_WARNING,
+@@ -121,8 +114,7 @@ class TypeValidator {
        MISSING_EXTENDS_TAG_WARNING,
        DUP_VAR_DECLARATION,
        HIDDEN_PROPERTY_MISMATCH,

+          "of the property it overrides from interface {1}\n" +
+          "original: {2}\n" +
+          "override: {3}");
+
   static final DiagnosticType UNKNOWN_OVERRIDE =
       DiagnosticType.warning(
           "JSC_UNKNOWN_OVERRIDE",
@@ -232,6 +240,7 @@ public class TypeCheck implements NodeTraversal.Callback, CompilerPass {
       HIDDEN_SUPERCLASS_PROPERTY,
       HIDDEN_INTERFACE_PROPERTY,
       HIDDEN_SUPERCLASS_PROPERTY_MISMATCH,

       }
     }
 
diff --git a/src/com/google/javascript/jscomp/TypeValidator.java b/src/com/google/javascript/jscomp/TypeValidator.java
index 24bf792f..1d585226 100644
--- a/src/com/google/javascript/jscomp/TypeValidator.java
+++ b/src/com/google/javascript/jscomp/TypeValidator.java
@@ -107,13 +107,6 @@ class TypeValidator {
           "JSC_INTERFACE_METHOD_NOT_IMPLEMENTED",
           "property {0} on interface {1} is not implemented by type {2}");
 
