VM [KERNEL] Avoid emitting :expr_temp and capturing :iterator

runtime/vm/scopes.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/scopes.h"
 
 #include "vm/object.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 
@@ skipping 621 matching lines @@
 
 void LocalScope::CaptureLocalVariables(LocalScope* top_scope) {
   ASSERT(top_scope->function_level() == function_level());
   LocalScope* scope = this;
   while (scope != top_scope->parent()) {
     for (intptr_t i = 0; i < scope->num_variables(); i++) {
       LocalVariable* variable = scope->VariableAt(i);
       if (variable->is_forced_stack() ||
           (variable->name().raw() == Symbols::StackTraceVar().raw()) ||
           (variable->name().raw() == Symbols::ExceptionVar().raw()) ||
-          (variable->name().raw() == Symbols::SavedTryContextVar().raw())) {
+          (variable->name().raw() == Symbols::SavedTryContextVar().raw()) ||
+          (variable->name().raw() == Symbols::IteratorParameter().raw())) {

[Vyacheslav Egorov (Google), 2017/03/27 14:31:46]

Can we move this to kernel_to_il.cc? We prefer to keep all scope related Kernel
specific changes confined to it.

Solution would be to find Symbols::IteratorParameter() named paramter and
set_is_forced_stack() it. 

         // Don't capture those variables because the VM expects them to be on
         // the stack.
         continue;
       }
       scope->CaptureVariable(variable);
     }
     scope = scope->parent();
   }
 }
 
@@ skipping 45 matching lines @@
     return fixed_parameter_count - (index() - kParamEndSlotFromFp);
   } else {
     // Shift negative indexes so that the lowest one is 0 (they are still
     // non-positive).
     return fixed_parameter_count - (index() - kFirstLocalSlotFromFp);
   }
 }
 
 
 }  // namespace dart