Fix bug in receiver-phi computation.

runtime/vm/intermediate_language.h

 // Copyright (c) 2013, 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_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 1984 matching lines @@
     kUnknownReceiver = -1,
     kNotReceiver = 0,
     kReceiver = 1
   };
 
   ReceiverType is_receiver() const {
     return static_cast<ReceiverType>(is_receiver_);
   }
 
   void set_is_receiver(ReceiverType is_receiver) {
-    ASSERT(is_receiver_ == kUnknownReceiver);
     is_receiver_ = is_receiver;
   }
 
  private:
   // Direct access to inputs_ in order to resize it due to unreachable
   // predecessors.
   friend class ConstantPropagator;
 
   void RawSetInputAt(intptr_t i, Value* value) { inputs_[i] = value; }
 
@@ skipping 6267 matching lines @@
   LocationSummary* Name::MakeLocationSummary(Zone* zone, bool opt) const {    \
     UNIMPLEMENTED();                                                          \
     return NULL;                                                              \
   }                                                                           \
   void Name::EmitNativeCode(FlowGraphCompiler* compiler) { UNIMPLEMENTED(); }
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_