invalid cast to int in generated sql with a char property

a class with a char property
public class User
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual char Type { get; set; }
}

and this query

var user = s.Query<User>().Where(x => x.Type == 'A').ToList();

generate incorrect sql with a cast to int

select user0_.UserId as UserId0_, user0_.Name as Name0_, user0_.Type as Type0_ from [User] user0_ where cast(user0_.Type as INT)=@p0
Name1 - Value:65