Remove use of JS templates in reified type information

pkg/compiler/lib/src/js_backend/constant_emitter.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import '../common.dart';
 import '../compiler.dart' show Compiler;
 import '../constants/values.dart';
 import '../dart_types.dart';
 import '../elements/elements.dart';
 import '../io/code_output.dart';
@@ skipping 302 matching lines @@
 
   String stripComments(String rawJavaScript) {
     return rawJavaScript.replaceAll(COMMENT_RE, '');
   }
 
   jsAst.Expression maybeAddTypeArguments(
       InterfaceType type, jsAst.Expression value) {
     if (type is InterfaceType &&
         !type.treatAsRaw &&
         backend.classNeedsRti(type.element)) {
-      InterfaceType interface = type;
-      RuntimeTypesEncoder rtiEncoder = backend.rtiEncoder;
-      Iterable<jsAst.Expression> arguments = interface.typeArguments.map(
-          (DartType type) =>
-              rtiEncoder.getTypeRepresentationWithPlaceholders(type, (_) {}));
-      jsAst.Expression argumentList =
-          new jsAst.ArrayInitializer(arguments.toList());
       return new jsAst.Call(
           getHelperProperty(backend.helpers.setRuntimeTypeInfo),
-          [value, argumentList]);
+          [value, _reifiedTypeArguments(type)]);
     }
     return value;
   }
 
+  jsAst.Expression _reifiedTypeArguments(InterfaceType type) {
+    jsAst.Expression unexpected(TypeVariableType variable) {
+      reporter.internalError(
+          NO_LOCATION_SPANNABLE,
+          "Unexpected type variable '${variable.getStringAsDeclared(null)}'"
+          " in constant type '${type.getStringAsDeclared(null)}'");
+      return null;
+    }
+    List<jsAst.Expression> arguments = <jsAst.Expression>[];
+    RuntimeTypesEncoder rtiEncoder = backend.rtiEncoder;
+    for (DartType argument in type.typeArguments) {
+      arguments.add(rtiEncoder.getTypeRepresentation(argument, unexpected));
+    }
+    return new jsAst.ArrayInitializer(arguments);
+  }
+
   @override
   jsAst.Expression visitDeferred(DeferredConstantValue constant, [_]) {
     return constantReferenceGenerator(constant.referenced);
   }
 }