WARNING pragmas in `Prelude.undefined` and `Prelude.error`

[Francesco Ariis]

On Sun, Dec 22, 2019 at 01:44:58PM +0200, Vilem Liepelt wrote:
> Has there been any discussion about adding WARNING pragmas to `Prelude.undefined` and `Prelude.error`, as done in some custom preludes?
> 
> I suppose this hasn't been done yet to avoid breaking existing code which makes "legitimate" use of those helpers?

`undefined` is useful when you want to check types in, e.g. ghcid, without
writing a function in full.
With -Wall on, that Warning could become annoying fast.