Collect type feedback for fields.

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
diff --git a/runtime/vm/parser.cc b/runtime/vm/parser.cc
index cb4bae56abe7598613b23681d1a61a701c2aed95..8dd1a560a6a16e02ffcc053886850ebc03506390 100644
--- a/runtime/vm/parser.cc
+++ b/runtime/vm/parser.cc
@@ -989,7 +989,6 @@ SequenceNode* Parser::ParseInstanceSetter(const Function& func) {
 
   StoreInstanceFieldNode* store_field =
       new StoreInstanceFieldNode(ident_pos, receiver, field, value);
-
   current_block_->statements->Add(store_field);
   current_block_->statements->Add(new ReturnNode(ident_pos));
   return CloseBlock();
@@ -1801,9 +1800,10 @@ void Parser::CheckConstFieldsInitialized(const Class& cls) {
   SequenceNode* initializers = current_block_->statements;
   for (int field_num = 0; field_num < fields.Length(); field_num++) {
     field ^= fields.At(field_num);
-    if (field.is_static() || !field.is_final()) {
+    if (field.is_static()) {
       continue;
     }
+
     bool found = false;
     for (int i = 0; i < initializers->length(); i++) {
       found = false;
@@ -1816,9 +1816,14 @@ void Parser::CheckConstFieldsInitialized(const Class& cls) {
         }
       }
     }
-    if (!found) {
+
+    if (found) continue;
+
+    if (field.is_final()) {
       ErrorMsg("final field '%s' not initialized",
                String::Handle(field.name()).ToCString());
+    } else {
+      field.UpdateCid(kNullCid);
     }
   }
 }