Set and keep parent function of signature functions.

runtime/vm/kernel_binary_flowgraph.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/kernel_binary_flowgraph.h"
 
 #include "vm/compiler.h"
 #include "vm/longjump.h"
 #include "vm/object_store.h"
 
@@ skipping 1462 matching lines @@
   // The spec describes in section "19.1 Static Types":
   //
   //     Any use of a malformed type gives rise to a static warning. A
   //     malformed type is then interpreted as dynamic by the static type
   //     checker and the runtime unless explicitly specified otherwise.
   //
   // So we convert malformed return/parameter types to `dynamic`.
   TypeParameterScope scope(this, first_item_offest, list_length);
 
   Function& signature_function = Function::ZoneHandle(
-      Z, Function::NewSignatureFunction(*active_class_->klass,
-                                        TokenPosition::kNoSource));
+      Z,
+      Function::NewSignatureFunction(*active_class_->klass, Function::Handle(Z),
+                                     TokenPosition::kNoSource));
 
   intptr_t required_count;
   intptr_t all_count;
   intptr_t positional_count;
   if (!simple) {
     required_count = builder_->ReadUInt();  // read required parameter count.
     all_count = builder_->ReadUInt();       // read total parameter count.
     positional_count =
         builder_->ReadListLength();  // read positional_parameters list length.
   } else {
@@ skipping 5434 matching lines @@
     metadata_values.SetAt(i, value);
   }
 
   return metadata_values.raw();
 }
 
 }  // namespace kernel
 }  // namespace dart
 
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)