Report arity errors on user definable operators.

sdk/lib/_internal/compiler/implementation/warnings.dart

Index: sdk/lib/_internal/compiler/implementation/warnings.dart
diff --git a/sdk/lib/_internal/compiler/implementation/warnings.dart b/sdk/lib/_internal/compiler/implementation/warnings.dart
index 5f5b74e096cb3497ae237f2f9a2d84ba719e57b6..bb0a7634c048cb200bb4cdc693c436c55e389a45 100644
--- a/sdk/lib/_internal/compiler/implementation/warnings.dart
+++ b/sdk/lib/_internal/compiler/implementation/warnings.dart
@@ -258,6 +258,24 @@ class MessageKind {
   static const EXTRA_FORMALS = const MessageKind(
       "Error: Formal parameters are not allowed here.");
 
+  static const UNARY_OPERATOR_BAD_ARITY = const MessageKind(
+      "Error: Operator #{1} must take no arguments.");
+
+  static const MINUS_OPERATOR_BAD_ARITY = const MessageKind(
+      "Error: Operator - must take 0 or 1 arguments.");
+
+  static const BINARY_OPERATOR_BAD_ARITY = const MessageKind(
+      "Error: Operator #{1} must take 1 argument.");
+
+  static const TERNARY_OPERATOR_BAD_ARITY = const MessageKind(
+      "Error: Operator #{1} must take 2 arguments.");
+
+  static const OPERATOR_OPTIONAL_ARGUMENTS = const MessageKind(
+      "Error: Operator #{1} cannot have optional arguments.");
+
+  static const OPERATOR_NAMED_ARGUMENTS = const MessageKind(
+      "Error: Operator #{1} cannot have named arguments.");
+
   // TODO(ahe): This message is hard to localize.  This is acceptable,
   // as it will be removed when we ship Dart version 1.0.
   static const DEPRECATED_FEATURE_WARNING = const MessageKind(