Re: [PATCH] libpoke: typify: Make cast error msgs more helpful

[Jose E. Marchesi]

Hi Mohammad.

> Type checking for "cast to struct type", incorrectly reports the
> location of expression's type, instead of the location of
> expression itself. This leads to a confusing error message when the
> expression is a function call.
>
> Running this code:
>
> ```
> fun f = uint16: { return 0; }
> type HL16 = struct uint<16> { uint8 hi; uint8 lo; };
> f as HL16;
> ```
>
> Emits this error message (which is confusing):
>
> ```
> t.pk:1:9: error: invalid cast, expected struct
> fun f = uint16: { return 0; }
>         ^~~~~~
> ```
>
> New behavior:
>
> ```
> t.pk:3:1: error: invalid cast, expected struct, got ushort
> f as HiLo16;
> ^
> ```
>
> Besides this fix, this commit also adds the type name of the unexpected
> type in the error message.

OK for both master and maint/poke-1.  Thanks.

> 2021-07-06  Mohammad-Reza Nabipoor  <mnabipoor@gnu.org>
>
>       * libpoke/pkl-typify.c (pkl_typify1_ps_cast): Make cast error
>       messages more helpful.
> ---
>  ChangeLog            |  5 +++++
>  libpoke/pkl-typify.c | 15 ++++++++++-----
>  2 files changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/ChangeLog b/ChangeLog
> index 76ea7c5d..2abd0dea 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,8 @@
> +2021-07-06  Mohammad-Reza Nabipoor  <mnabipoor@gnu.org>
> +
> +     * libpoke/pkl-typify.c (pkl_typify1_ps_cast): Make cast error
> +     messages more helpful.
> +
>  2021-06-06  Mohammad-Reza Nabipoor  <mnabipoor@gnu.org>
>  
>       * common/pk-utils.h (pk_format_binary): New function declaration.
> diff --git a/libpoke/pkl-typify.c b/libpoke/pkl-typify.c
> index 103d5113..73725ada 100644
> --- a/libpoke/pkl-typify.c
> +++ b/libpoke/pkl-typify.c
> @@ -493,8 +493,10 @@ PKL_PHASE_BEGIN_HANDLER (pkl_typify1_ps_cast)
>    if (PKL_AST_TYPE_CODE (type) == PKL_TYPE_STRUCT
>        && PKL_AST_TYPE_CODE (exp_type) != PKL_TYPE_STRUCT)
>      {
> -      PKL_ERROR (PKL_AST_LOC (exp_type),
> -                 "invalid cast, expected struct");
> +      char *found_type = pkl_type_str (exp_type, 1);
> +
> +      PKL_ERROR (PKL_AST_LOC (exp),
> +                 "invalid cast, expected struct, got %s", found_type);
>        PKL_TYPIFY_PAYLOAD->errors++;
>        PKL_PASS_ERROR;
>      }
> @@ -509,9 +511,12 @@ PKL_PHASE_BEGIN_HANDLER (pkl_typify1_ps_cast)
>          ;
>        else
>          {
> -          PKL_ERROR (PKL_AST_LOC (type),
> -                     "invalid cast, expected struct%s",
> -                     PKL_AST_TYPE_S_ITYPE (exp_type) ? " or integer" : "");
> +          char *type_str = pkl_type_str (type, 1);
> +
> +          PKL_ERROR (
> +              PKL_AST_LOC (type), "invalid cast, expected struct%s, got %s",
> +              PKL_AST_TYPE_S_ITYPE (exp_type) ? " or integral type" : "",
> +              type_str);
>            PKL_TYPIFY_PAYLOAD->errors++;
>            PKL_PASS_ERROR;
>          }