Re: new warnings in 4.5a: bint expected, bignum provided

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Hi Sven,

> Hi.
>=20
> I am seeing new (spurious?) warnings for the current unstable version (x8=
6_64 and x32-ABI):
>=20
> "bint" expected, "bignum" provided
>=20
> A minimal example:
>=20
> bugz11.scm:
> ---
> (module bugz11
>   (export
>    (list-ref-check::obj l pos::bint))
>   (main main))
>=20
> (define (list-ref-check l pos)
>   (let iter ()
>     (if (pair? l)
>         (cond ((=3D pos 0)
>                (car l))
>           (else
>             (set! l (cdr l))
>             (set! pos (- pos 1))
>             (iter)))
>         #f)))
>=20
> (define (main args)
>   (let ((val (list-ref-check args 1)))
>     (display val)
>     (newline)
>     0))
> ---
>=20
>  > bigloo -O3 -ldopt "-static" -o bugz11 bugz11.scm
>=20
> File "bugz11.scm", line 14, character 370:
> #            (set! pos (- pos 1))
> #                      ^
> *** WARNING: iter
> Type error --  "bint" expected, "bignum" provided
Actually, I think this new behavior is correct. The previous Bigloo versions
were simply not able to detect that potential error. Let me explain.

The "(- pos 1)" expression may overflow and then produce a bignum
value. This is incompatible the "bint" type assigned to pos. I think that to
get rid of the warning, you should use the "-fx" operator that will not
produce a bignum value. Does this make sense to you? Do you agree that
this new behavior is the one we should expect?

=2D-=20
Manuel

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