Allow access to type variables as expressions in factory constructors.

pkg/compiler/lib/src/elements/elements.dart

Index: pkg/compiler/lib/src/elements/elements.dart
diff --git a/pkg/compiler/lib/src/elements/elements.dart b/pkg/compiler/lib/src/elements/elements.dart
index 8cda9671a994680c4fa1da6356c522bc407a220c..dc8650408d5eda22cf29027819a3b56d05381456 100644
--- a/pkg/compiler/lib/src/elements/elements.dart
+++ b/pkg/compiler/lib/src/elements/elements.dart
@@ -490,6 +490,12 @@ class Elements {
     return true;
   }
 
+  static bool hasAccessToTypeVariables(Element element) {
+    Element outer = element.outermostEnclosingMemberOrTopLevel;
+    return (outer != null && outer.isFactoryConstructor) ||
+        !isInStaticContext(element);
+  }
+
   static bool isStaticOrTopLevelField(Element element) {
     return isStaticOrTopLevel(element)
            && (identical(element.kind, ElementKind.FIELD)