Re: ICE on procedure-local CONST declaration

[Gaius Mulley]

Alcor <alcor@tilde.club> writes:

> Hi all,
>
> The following program (Test.mod) causes an ICE on gm2 (GCC) 15.0.1 20240707 
> (x86_64, Arch Linux):
>
> --
>
> MODULE Test;
>
> IMPORT SYSTEM;
>
> TYPE
>       T = POINTER TO CONS;
>       CONS = RECORD
>               CAR: SYSTEM.ADDRESS;
>               CDR: T;
>       END;
>
> PROCEDURE POP(VAR LST: T): SYSTEM.ADDRESS;
>       CONST CAR = LST.CAR;
> BEGIN
>       RETURN NIL;
> END POP;
>
> BEGIN
> END Test.
>
> --
>
> I am not entirely sure whether this is valid Modula-2 code. I'm just
> experimenting with the compiler by attempting to write a toy Lisp
> implementation in M2 and thought this may be worth reporting.
>

Hi Alcor,

many thanks for the bug report - now fixed in the gcc git,

regards,
Gaius


$ gm2 -c badconst.mod 
badconst.mod:13:13: error: In procedure ‘POP’: not expecting a variable ‘LST’ 
as a term in a constant expression
   13 | CONST CAR = LST.CAR;
      |             ^~~