Removing -fext-core

Austin Seipp austin at
Sun Apr 27 13:14:20 UTC 2014

Hello all,

Recently I was wondering something: is there any reason to keep
-fext-core around? In particular, it's been broken for a while at this
point, see GHC bug #5630[1]

As far as I'm aware there really aren't any users of it still around
these days, at least none working with a modern GHC. And it seems like
if people were to need access to Core, they could use a plugin or some
such to get direct access to what they want.

Simon mentioned removing ExtCore in face of replacing it with IfaceSyn
in the compiler. I'm not entirely sure how much work that would be to
bring it all up to scratch if people needed it, but maybe it's worth
thinking about.

One other issue is a notion of semantics which is present in External
Core, but we also now have a documented semantics for GHC's core
language as well (which has evolved quite a bit), so I don't know how
much that matters.

So long story short: I don't think anyone is using it, maintaining it,
and it seems subsumed by more recent events.

Therefore, if nobody objects, I'd vote to remove -fext-core from GHC,
unless someone is willing to step up and really maintain it. If you're
using it, you should probably speak up soon I'd imagine...



Austin Seipp, Haskell Consultant
Well-Typed LLP,

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