[Bug modula2/117371] New: [14.2 Regression] type incompatibility between ‘INTEGER’ and ‘CARDINAL’

[ludovic--- via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117371

            Bug ID: 117371
           Summary: [14.2 Regression] type incompatibility between
                    ‘INTEGER’ and ‘CARDINAL’
           Product: gcc
           Version: 14.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: modula2
          Assignee: gaius at gcc dot gnu.org
          Reporter: ludo...@ludovic-brenta.org
  Target Milestone: ---

The following compiles and runs fine with gm2 13.0:

(* -*- mode: Modula-2; compile-command: "gm2 -fiso -g -O2 -o primes primes.mod"
-*- *)

MODULE primes;
FROM STextIO IMPORT WriteString, WriteLn, ReadChar;
FROM SWholeIO IMPORT WriteCard;
IMPORT RealMath;

PROCEDURE Compute_Primes (is_prime : ARRAY OF BOOLEAN);
VAR
     k, m : CARDINAL; (* line 10 *)
BEGIN
     FOR k := 1 TO HIGH (is_prime) DO is_prime[k] := TRUE; END;
     WriteCard (1, 1);
     WriteString (" ");
     FOR k := 2 TO HIGH (is_prime) DO
          IF is_prime[k] THEN
               WriteCard (k, 1);
               WriteString (" ");
          END;
          FOR m := k * k TO HIGH (is_prime) BY k DO (* line 20 *)
               is_prime[m] := FALSE;
          END;
     END;
     WriteLn;
END Compute_Primes;

VAR
     is_prime : ARRAY [1 .. 16 * 1024] OF BOOLEAN;
BEGIN
     Compute_Primes (is_prime);
END primes.


When recompiling the same with gm2 14.0, I get:

gm2 -fiso -g -O2 -o primes primes.mod
cc1gm2: error: In procedure ‘Compute_Primes’: type incompatibility between
‘INTEGER’ and ‘CARDINAL’

There is no indication on the location of the error.
If, at line 10, I change CARDINAL to INTEGER I get:

gm2 -fiso -g -O2 -o primes primes.mod
primes.mod:20:35: error: In procedure ‘Compute_Primes’: type incompatibility
between ‘INTEGER’ and ‘CARDINAL’
   20 |           FOR m := k * k TO HIGH (is_prime) BY k DO
      |                             ~~~~~~^~~~~~~~

Now there is a location for the error but I think the error is legit as
m, k, k*k, are INTEGER whereas HIGH returns a CARDINAL.  So I think the
bug is triggered by the original code where m and k are CARDINALs.

By the way:

gm2 --version -fiso -g -O2 -o primes primes.mod
gm2 (Debian 14.2.0-3) 14.2.0
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.