public override void VisitIsExpression (IsExpression isExpression)
{
base.VisitIsExpression (isExpression);
var p = isExpression.Type as PrimitiveType;
if (p != null) {
var e = isExpression.Expression;
e.Remove ();
var n = new BinaryOperatorExpression (
new MemberReferenceExpression (e, "constructor"),
BinaryOperatorType.Equality,
new TypeReferenceExpression (GetJsConstructorType (isExpression.Type)));
isExpression.ReplaceWith (n);
}
}