Avoid MSVC's C6323 warning (use of arithmetic operator on Boolean type)

src/runtime/runtime-scopes.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/arguments.h"
 #include "src/frames-inl.h"
 #include "src/runtime/runtime-utils.h"
@@ skipping 88 matching lines @@
     HandleScope scope(isolate);
     Handle<String> name(String::cast(pairs->get(i)));
     Handle<Object> initial_value(pairs->get(i + 1), isolate);
 
     // We have to declare a global const property. To capture we only
     // assign to it when evaluating the assignment for "const x =
     // <expr>" the initial value is the hole.
     bool is_var = initial_value->IsUndefined();
     bool is_const = initial_value->IsTheHole();
     bool is_function = initial_value->IsSharedFunctionInfo();
-    DCHECK(is_var + is_const + is_function == 1);
+    DCHECK_EQ(1,
+              BoolToInt(is_var) + BoolToInt(is_const) + BoolToInt(is_function));
 
     Handle<Object> value;
     if (is_function) {
       // Copy the function and update its context. Use it as value.
       Handle<SharedFunctionInfo> shared =
           Handle<SharedFunctionInfo>::cast(initial_value);
       Handle<JSFunction> function =
           isolate->factory()->NewFunctionFromSharedFunctionInfo(shared, context,
                                                                 TENURED);
       value = function;
@@ skipping 93 matching lines @@
   CONVERT_ARG_HANDLE_CHECKED(String, name, 1);
   CONVERT_SMI_ARG_CHECKED(attr_arg, 2);
   PropertyAttributes attr = static_cast<PropertyAttributes>(attr_arg);
   RUNTIME_ASSERT(attr == READ_ONLY || attr == NONE);
   CONVERT_ARG_HANDLE_CHECKED(Object, initial_value, 3);
 
   // TODO(verwaest): Unify the encoding indicating "var" with DeclareGlobals.
   bool is_var = *initial_value == NULL;
   bool is_const = initial_value->IsTheHole();
   bool is_function = initial_value->IsJSFunction();
-  DCHECK(is_var + is_const + is_function == 1);
+  DCHECK_EQ(1,
+            BoolToInt(is_var) + BoolToInt(is_const) + BoolToInt(is_function));
 
   int index;
   PropertyAttributes attributes;
   ContextLookupFlags flags = DONT_FOLLOW_CHAINS;
   BindingFlags binding_flags;
   Handle<Object> holder =
       context->Lookup(name, flags, &index, &attributes, &binding_flags);
 
   Handle<JSObject> object;
   Handle<Object> value =
@@ skipping 845 matching lines @@
   return Smi::FromInt(frame->GetArgumentsLength());
 }
 
 
 RUNTIME_FUNCTION(RuntimeReference_Arguments) {
   SealHandleScope shs(isolate);
   return __RT_impl_Runtime_GetArgumentsProperty(args, isolate);
 }
 }
 }  // namespace v8::internal