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 8b6ccfb525570a5b15857fa55db1582130946663..bcf85bf673964c77235a2c3cae1ab3cbb18655ac 100644
--- a/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
+++ b/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
@@ -945,6 +945,16 @@ 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';
   }