private Expr MakeUnaryIntUFFunctionCall(string functionName, Type resultType, Expr arg)
{
Function f = verifier.GetOrCreateUnaryUF(functionName, resultType, arg.Type);
var e = new NAryExpr(Token.NoToken, new FunctionCall(f), new List <Expr> {
arg
});
e.Type = resultType;
return(e);
}