Address comments from 820093006

dart/pkg/compiler/lib/src/resolution/members.dart

Index: dart/pkg/compiler/lib/src/resolution/members.dart
diff --git a/dart/pkg/compiler/lib/src/resolution/members.dart b/dart/pkg/compiler/lib/src/resolution/members.dart
index 18309afce5bab2af2f045ba96af5fb3d8d733c41..b34ede20eb015eb51bcdc3bdfd29c23fcfea8e05 100644
--- a/dart/pkg/compiler/lib/src/resolution/members.dart
+++ b/dart/pkg/compiler/lib/src/resolution/members.dart
@@ -2233,6 +2233,9 @@ class ResolverVisitor extends MappingVisitor<ResolutionResult> {
                                                  MessageKind kind,
                                                  [Map arguments = const {}]) {
     compiler.reportWarning(node, kind, arguments);
+    // TODO(ahe): Use [allowedCategory] to synthesize a more precise subclass
+    // of [ErroneousElementX]. For example, [ErroneousFieldElementX],
+    // [ErroneousConstructorElementX], etc.
     return new ErroneousElementX(kind, arguments, name, enclosingElement);
   }
 
@@ -4922,18 +4925,18 @@ class ConstructorResolver extends CommonResolverVisitor<Element> {
     } else if (element.isTypedef) {
       error(node, MessageKind.CANNOT_INSTANTIATE_TYPEDEF,
             {'typedefName': name});
-      element = new ErroneousElementX(
+      element = new ErroneousConstructorElementX(
           MessageKind.CANNOT_INSTANTIATE_TYPEDEF,
           {'typedefName': name}, name, resolver.enclosingElement);
     } else if (element.isTypeVariable) {
       error(node, MessageKind.CANNOT_INSTANTIATE_TYPE_VARIABLE,
             {'typeVariableName': name});
-      element = new ErroneousElementX(
+      element = new ErroneousConstructorElementX(
           MessageKind.CANNOT_INSTANTIATE_TYPE_VARIABLE,
           {'typeVariableName': name}, name, resolver.enclosingElement);
     } else if (!element.isClass && !element.isPrefix) {
       error(node, MessageKind.NOT_A_TYPE, {'node': name});
-      element = new ErroneousElementX(
+      element = new ErroneousConstructorElementX(
           MessageKind.NOT_A_TYPE, {'node': name}, name,
           resolver.enclosingElement);
     }