Separating typechecking and type error reporting in two passes?

Joachim Breitner mail at
Wed Nov 30 14:02:12 UTC 2016


Am Mittwoch, den 30.11.2016, 12:59 +0100 schrieb MarLinn via ghc-devs:
> > But you are right that when the programmer sits there and waits for a
> > result, that’s when snappyness is important.
> I had a random idea based on this observation:

please allow me to re-iterate that my proposal is *not* about
performance, but about being able to detect and report typical error
patterns such as confusing the order of arguments to a function, or to
leave out one argument. (Wouldn’t that be great?)

I regret pointing out hypothetical and likely insignificant performance
effects; it derails the discussion.

Your ideas (printing less errors, or less details, at first until
asked) can be pursued already now. There is precedent, e.g.
which added the -freverse-errors option. Options in similar vain
(-fone-line-errors, -fnum-errors=1) are worth considering and can be
implemented today, so if you feel like it, do explain your ideas in
greater detail.


Joachim “nomeata” Breitner
  mail at joachim-breitner.de
  XMPP: nomeata at • OpenPGP-Key: 0xF0FBF51F
  Debian Developer: nomeata at
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: This is a digitally signed message part
URL: <>

More information about the ghc-devs mailing list