Do not ignore side effects of a type test or type cast as expression, such

runtime/vm/intermediate_language.cc

 // 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.
 
 #include "vm/intermediate_language.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/bit_vector.h"
 #include "vm/cpu.h"
 #include "vm/dart_entry.h"
@@ skipping 16 matching lines @@
 
 DEFINE_FLAG(bool, propagate_ic_data, true,
     "Propagate IC data from unoptimized to optimized IC calls.");
 DEFINE_FLAG(bool, unbox_numeric_fields, true,
     "Support unboxed double and float32x4 fields.");
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, eliminate_type_checks);
 DECLARE_FLAG(bool, trace_optimization);
 DECLARE_FLAG(bool, trace_constant_propagation);
 DECLARE_FLAG(bool, throw_on_javascript_int_overflow);
-DECLARE_FLAG(bool, enable_type_checks);
 
 Definition::Definition()
     : range_(NULL),
       type_(NULL),
       temp_index_(-1),
       ssa_temp_index_(-1),
       input_use_list_(NULL),
       env_use_list_(NULL),
       use_kind_(kValue),  // Phis and parameters rely on this default.
       constant_value_(Object::ZoneHandle(ConstantPropagator::Unknown())) {
@@ skipping 1469 matching lines @@
   // are constant, instantiate the target type here.
   if (dst_type().IsInstantiated()) return this;
 
   ConstantInstr* constant_type_args =
       instantiator_type_arguments()->definition()->AsConstant();
   if (constant_type_args != NULL &&
       !constant_type_args->value().IsNull() &&
       constant_type_args->value().IsTypeArguments()) {
     const TypeArguments& instantiator_type_args =
         TypeArguments::Cast(constant_type_args->value());
+    Error& bound_error = Error::Handle();
     const AbstractType& new_dst_type = AbstractType::Handle(
-        dst_type().InstantiateFrom(instantiator_type_args, NULL));
+        dst_type().InstantiateFrom(instantiator_type_args, &bound_error));
     // If dst_type is instantiated to dynamic or Object, skip the test.
-    if (!new_dst_type.IsMalformedOrMalbounded() &&
+    if (!new_dst_type.IsMalformedOrMalbounded() && bound_error.IsNull() &&
         (new_dst_type.IsDynamicType() || new_dst_type.IsObjectType())) {
       return value()->definition();
     }
     set_dst_type(AbstractType::ZoneHandle(new_dst_type.Canonicalize()));
     if (FLAG_eliminate_type_checks &&
         value()->Type()->IsAssignableTo(dst_type())) {
       return value()->definition();
     }
     ConstantInstr* null_constant = flow_graph->constant_null();
     instantiator_type_arguments()->BindTo(null_constant);
@@ skipping 1710 matching lines @@
     case Token::kTRUNCDIV: return 0;
     case Token::kMOD: return 1;
     default: UNIMPLEMENTED(); return -1;
   }
 }
 
 
 #undef __
 
 }  // namespace dart