[m-rev.] for post-commit review: warn about bad coerce arities

[Zoltan Somogyi]

For review by Peter.

Zoltan.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Log.ca
Type: application/octet-stream
Size: 160 bytes
Desc: not available
URL: <http://lists.mercurylang.org/archives/reviews/attachments/20240527/7b7517fb/attachment.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: DIFF.ca
Type: application/octet-stream
Size: 4366 bytes
Desc: not available
URL: <http://lists.mercurylang.org/archives/reviews/attachments/20240527/7b7517fb/attachment-0001.obj>