25 Nov
2019
25 Nov
'19
11:37 a.m.
On Mon, 25 Nov 2019, Bertram Felgenhauer via Libraries wrote:
Oleg Grenrus wrote:
I cannot see any justification for that instance
-- | @since 4.11.0.0 instance Fail.MonadFail (ST s) where fail s = errorWithoutStackTrace s
It's certainly not in the spirit of the MonadFail proposal. Arguably, *all* implementations of `fail` in terms of `error*` are wrong, even the one for IO. (I suspect dropping the instance for IO would cause a lot of pain though...)
Isn't fail in IO a synonym for (ioError . userError) ?