In background compilation make a copy of Field in order to freeze its state

runtime/vm/ast_transformer.cc

Index: runtime/vm/ast_transformer.cc
diff --git a/runtime/vm/ast_transformer.cc b/runtime/vm/ast_transformer.cc
index 8b14e299bf7fa5a93715ac2a6814468e3614b6c0..a534a057acba7bea3381ab3a1ef65adf637af302 100644
--- a/runtime/vm/ast_transformer.cc
+++ b/runtime/vm/ast_transformer.cc
@@ -522,7 +522,7 @@ void AwaitTransformer::VisitLoadStaticFieldNode(LoadStaticFieldNode* node) {
 void AwaitTransformer::VisitStoreStaticFieldNode(StoreStaticFieldNode* node) {
   AstNode* new_value = Transform(node->value());
   result_ = new(Z) StoreStaticFieldNode(node->token_pos(),
-                                        node->field(),
+                                        *node->field().OriginalAsHandle(Z),

[siva, 2016/02/25 23:38:32]

ditto comment.

[srdjan, 2016/02/26 00:40:42]

Resolved using Field::ZoneHandle

                                         new_value);
 }