Abandon type inference on closures that (potentially) flow into Function.apply.

pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart

Index: pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
diff --git a/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart b/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
index d546679a536744760c2881ff0ac9f803605889c1..efaae28d3b728f86ccb1c037e2e8c4a3bc2b79e6 100644
--- a/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
+++ b/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
@@ -1037,16 +1037,16 @@ class TypeGraphInferrerEngine
       if (parameter.functionDeclaration.isInstanceMember) {
         ParameterAssignments assignments = info.assignments;
         assignments.replace(existing, type);
-        type.addUser(info);
       } else {
         List<TypeInformation> assignments = info.assignments;
         for (int i = 0; i < assignments.length; i++) {
           if (assignments[i] == existing) {
             assignments[i] = type;
-            type.addUser(info);
           }
         }
       }
+      // Also forward all users.
+      type.addUsersOf(existing);
     } else {
       assert(existing == null);
     }