Makes method shadowing a getter or setter or vice versa a compile time error.

compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java

Index: compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
diff --git a/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java b/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
index 75ea7f9016f281a985472570b280172415adac89..303ee79c6e8dd9041d38e9f85284e7a083b9b433 100644
--- a/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
+++ b/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
@@ -56,8 +56,8 @@ public enum TypeErrorCode implements ErrorCode {
   SETTER_TYPE_MUST_BE_ASSIGNABLE("Setter type '%s' must be assignable to getter type '%s'"),
   STATIC_MEMBER_ACCESSED_THROUGH_INSTANCE(
       "static member %s of %s cannot be accessed through an instance"),
-  SUPERTYPE_HAS_FIELD("%s is a field in %s"),
-  SUPERTYPE_HAS_METHOD("%s is a method in %s"),
+  SUPERTYPE_HAS_FIELD(ErrorSeverity.ERROR, "%s is a field in %s"),
+  SUPERTYPE_HAS_METHOD(ErrorSeverity.ERROR, "%s is a method in %s"),
   TYPE_VARIABLE_IN_STATIC_CONTEXT("cannot access type variable %s in static context"),
   TYPE_NOT_ASSIGNMENT_COMPATIBLE("'%s' is not assignable to '%s'"),
   USE_ASSIGNMENT_ON_SETTER("Use assignment to set field \"%s\" in %s"),