Add assertion for variable index of reused potentially reused AST nodes.

runtime/vm/flow_graph_builder.cc

 // Copyright (c) 2012, 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/flow_graph_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/class_finalizer.h"
@@ skipping 2364 matching lines @@
 }
 
 
 void EffectGraphVisitor::BuildLetTempExpressions(LetNode* node) {
   intptr_t num_temps = node->num_temps();
   for (intptr_t i = 0; i < num_temps; ++i) {
     ValueGraphVisitor for_value(owner());
     node->InitializerAt(i)->Visit(&for_value);
     Append(for_value);
     Value* temp_val = for_value.value();
+    ASSERT(!node->TempAt(i)->HasIndex() ||
+           (node->TempAt(i)->index() == GetCurrentTempLocalIndex()));
     node->TempAt(i)->set_index(GetCurrentTempLocalIndex());
     Do(new(Z) PushTempInstr(temp_val));
     owner()->AllocateTemp();
   }
 }
 
 
 void EffectGraphVisitor::VisitLetNode(LetNode* node) {
   BuildLetTempExpressions(node);
 
@@ skipping 1977 matching lines @@
   Report::MessageF(Report::kBailout,
                    Script::Handle(function.script()),
                    function.token_pos(),
                    "FlowGraphBuilder Bailout: %s %s",
                    String::Handle(function.name()).ToCString(),
                    reason);
   UNREACHABLE();
 }
 
 }  // namespace dart