Fix a duplicate AST ID recorded for for/in.

src/arm/full-codegen-arm.cc

Index: src/arm/full-codegen-arm.cc
diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index 2685fcb735cee0501a1d20c5c5231dc75375fdd6..3649941f92e73c936de71e48f174a3e3b69a7490 100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -1656,10 +1656,20 @@ void FullCodeGenerator::EmitAssignment(Expression* expr, int bailout_ast_id) {
     }
     case KEYED_PROPERTY: {
       __ push(r0);  // Preserve value.
-      VisitForStackValue(prop->obj());
-      VisitForAccumulatorValue(prop->key());
-      __ mov(r1, r0);
-      __ pop(r2);
+      if (prop->is_synthetic()) {
+        ASSERT(prop->obj()->AsVariableProxy() != NULL);
+        ASSERT(prop->key()->AsLiteral() != NULL);
+        { AccumulatorValueContext for_object(this);
+          EmitVariableLoad(prop->obj()->AsVariableProxy()->var());
+        }
+        __ mov(r2, r0);
+        __ mov(r1, Operand(prop->key()->AsLiteral()->handle()));
+      } else {
+        VisitForStackValue(prop->obj());
+        VisitForAccumulatorValue(prop->key());
+        __ mov(r1, r0);
+        __ pop(r2);
+      }
       __ pop(r0);  // Restore value.
       Handle<Code> ic(Builtins::builtin(Builtins::KeyedStoreIC_Initialize));
       EmitCallIC(ic, RelocInfo::CODE_TARGET);