https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114380
--- Comment #3 from Gaius Mulley <gaius at gcc dot gnu.org> ---
$ gm2 tiny4.mod
tiny4.mod:13:17: error: In program module ‘tiny4’: type incompatibility between
‘BITSET’ and ‘WORD’
13 | b := func () - {6..31}
| ~~~~~~~~^~~~~~~~~
