Local closures may be the only survivors in a library.

runtime/vm/precompiler.h

 // Copyright (c) 2015, 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.
 
 #ifndef VM_PRECOMPILER_H_
 #define VM_PRECOMPILER_H_
 
 #include "vm/allocation.h"
 #include "vm/hash_map.h"
 #include "vm/hash_table.h"
@@ skipping 291 matching lines @@
   void AddField(const Field& field);
   void AddFunction(const Function& function);
   void AddInstantiatedClass(const Class& cls);
   void AddSelector(const String& selector);
   bool IsSent(const String& selector);
 
   void ProcessFunction(const Function& function);
   void CheckForNewDynamicFunctions();
   void TraceConstFunctions();
 
+  void TraceForRetainedFunctions();
   void DropFunctions();
   void DropFields();
   void TraceTypesFromRetainedClasses();
   void DropTypes();
   void DropTypeArguments();
   void DropClasses();
   void DropLibraries();
 
   void BindStaticCalls();
   void SwitchICCalls();
@@ skipping 33 matching lines @@
   intptr_t dropped_class_count_;
   intptr_t dropped_typearg_count_;
   intptr_t dropped_type_count_;
   intptr_t dropped_library_count_;
 
   GrowableObjectArray& libraries_;
   const GrowableObjectArray& pending_functions_;
   SymbolSet sent_selectors_;
   FunctionSet enqueued_functions_;
   FieldSet fields_to_retain_;
+  FunctionSet functions_to_retain_;
   ClassSet classes_to_retain_;
   TypeArgumentsSet typeargs_to_retain_;
   AbstractTypeSet types_to_retain_;
   InstanceSet consts_to_retain_;
   Error& error_;
 };
 
 
 class FunctionsTraits {
  public:
@@ skipping 21 matching lines @@
     return function.raw();
   }
 };
 
 typedef UnorderedHashSet<FunctionsTraits> UniqueFunctionsSet;
 
 
 }  // namespace dart
 
 #endif  // VM_PRECOMPILER_H_