Report errors and warnings for hiding elements, issue 572.

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

Index: compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java
diff --git a/compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java b/compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java
index 81abd2af5e9d0a193e329a98c3a3658c53b9601a..412af3a62ff61de3f54e0c9eecbf12fc9d076d8c 100644
--- a/compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java
+++ b/compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java
@@ -24,8 +24,7 @@ public enum ResolverErrorCode implements ErrorCode {
   CANNOT_INIT_STATIC_FIELD_IN_INITIALIZER("Cannot initialize a static field in an initializer list"),
   CANNOT_OVERRIDE_INSTANCE_MEMBER("static member cannot override instance member %s of %s"),
   CANNOT_OVERRIDE_STATIC_MEMBER("cannot override static member %s of %s"),
-  CANNOT_OVERRIDE_METHOD_WRONG_NUM_PARAMS(
-      "cannot override method %s, wrong number of parameters"),
+  CANNOT_OVERRIDE_METHOD_WRONG_NUM_PARAMS("cannot override method %s, wrong number of parameters"),
   CANNOT_OVERRIDE_METHOD_NUM_NAMED_PARAMS(
       "cannot override method %s, number of named parameters doesn't match"),
   CANNOT_OVERRIDE_METHOD_ORDER_NAMED_PARAMS(
@@ -49,8 +48,18 @@ public enum ResolverErrorCode implements ErrorCode {
   CYCLIC_CLASS("%s causes a cycle in the supertype graph"),
   DID_YOU_MEAN_NEW("%1$s is a %2$s. Did you mean (new %1$s)?"),
   DUPLICATED_INTERFACE("%s and %s are duplicated in the supertype graph"),
+  DUPLICATE_FUNCTION_EXPRESSION(ErrorSeverity.ERROR, "Duplicate function expression '%s'"),
+  DUPLICATE_FUNCTION_EXPRESSION_WARNING(ErrorSeverity.WARNING,
+      "Function expression '%s' is hiding '%s' at %s"),
+  DUPLICATE_LOCAL_VARIABLE_ERROR(ErrorSeverity.ERROR, "Duplicate local variable '%s'"),
+  DUPLICATE_LOCAL_VARIABLE_WARNING(ErrorSeverity.WARNING,
+      "Local variable '%s' is hiding '%s' at %s"),
   DUPLICATE_MEMBER("Duplicate member '%s'"),
+  DUPLICATE_PARAMETER(ErrorSeverity.ERROR, "Duplicate parameter '%s'"),
+  DUPLICATE_PARAMETER_WARNING(ErrorSeverity.WARNING, "Parameter '%s' is hiding '%s' at %s"),
   DUPLICATE_TOP_LEVEL_DEFINITION("duplicate top-level definition '%s'"),
+  DUPLICATE_TYPE_VARIABLE(ErrorSeverity.ERROR, "Duplicate type variable '%s'"),
+  DUPLICATE_TYPE_VARIABLE_WARNING(ErrorSeverity.WARNING, "Type variable '%s' is hiding '%s' at %s"),
   DYNAMIC_EXTENDS("Dynamic can not be used as superclass"),
   DYNAMIC_IMPLEMENTS("Dynamic can not be used as superinterface"),
   EXPECTED_AN_INSTANCE_FIELD_IN_SUPER_CLASS(