Implement type argument access and reification of runtime types.

pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart

Index: pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
diff --git a/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart b/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
index 787dd5f3739eadb55c92ce7f6adfe5a1fe42534f..a09107aa1fd971c678d91fcfe511cdad0e1c8d60 100644
--- a/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
+++ b/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
@@ -950,6 +950,16 @@ class ASTEmitter
     return errorUnsupportedNode(node);
   }
 
+  @override
+  Expression visitReadTypeVariable(tree.ReadTypeVariable node, arg) {
+    return errorUnsupportedNode(node);
+  }
+
+  @override
+  Expression visitReifyRuntimeType(tree.ReifyRuntimeType node, arg) {
+    return errorUnsupportedNode(node);
+  }
+
   errorUnsupportedNode(tree.JsSpecificNode node) {
     throw '$node not supported by dart backend';
   }