Adjusts dart2js backend to handle method type arguments.

pkg/compiler/lib/src/diagnostics/messages.dart

Index: pkg/compiler/lib/src/diagnostics/messages.dart
diff --git a/pkg/compiler/lib/src/diagnostics/messages.dart b/pkg/compiler/lib/src/diagnostics/messages.dart
index bbe777e09c6d537b8596815b896b5499d80e37ce..4baa88972f6daf7aa7fa53a0cdeeb275eb87c8c3 100644
--- a/pkg/compiler/lib/src/diagnostics/messages.dart
+++ b/pkg/compiler/lib/src/diagnostics/messages.dart
@@ -430,6 +430,7 @@ enum MessageKind {
   TYPE_ARGUMENT_COUNT_MISMATCH,
   TYPE_VARIABLE_IN_CONSTANT,
   TYPE_VARIABLE_WITHIN_STATIC_MEMBER,
+  TYPE_VARIABLE_FROM_METHOD_NOT_REIFIED,
   TYPEDEF_FORMAL_WITH_DEFAULT,
   UNARY_OPERATOR_BAD_ARITY,
   UNBOUND_LABEL,
@@ -1152,6 +1153,36 @@ void main() => new C().m(null);
 """
           ]),
 
+      MessageKind.TYPE_VARIABLE_FROM_METHOD_NOT_REIFIED: const MessageTemplate(
+          MessageKind.TYPE_VARIABLE_FROM_METHOD_NOT_REIFIED,
+          "Method type variables are not reified.",
+          howToFix: "Try using the intended upper bound of the "
+              "type variable, or dynamic."

[Johnni Winther, 2016/05/23 12:50:41]

You can add an [options] argument to MessageTemplate to make the examples work.

And I think you need to add checks for and use fo this message template in
resolution/members.dart in handleIs, handleAs, and
handleTypeVariableTypeLiteralAccess

[eernst, 2016/05/23 14:30:24]

Marked as TODOs for the next CL.

+// GENERIC_METHODS: These examples can be commented in when the compiler
+// supports generic methods without an option:
+//
+//        examples: const [
+//            """
+// // Method type variables are not reified, so they cannot be returned.
+// Type f<T>() => T;
+//
+// main() => f<int>();
+// """,
+//            """
+// // Method type variables are not reified, so they cannot be tested dynamically.
+// bool f<T>(Object o) => o is T;
+//
+// main() => f<int>(42);
+// """,
+//            """
+// // Method type variables are not reified, so they cannot be tested dynamically.
+// bool f<T>(Object o) => o as T;
+//
+// main() => f<int>(42);
+// """
+//    ]
+      ),
+
       MessageKind.INVALID_TYPE_VARIABLE_BOUND: const MessageTemplate(
           MessageKind.INVALID_TYPE_VARIABLE_BOUND,
           "'#{typeArgument}' is not a subtype of bound '#{bound}' for "