Ah. Hmm. I see.
Can you try this in TcEvidence
-- We expect only coercion bindings
go_bind :: EvBind -> VarSet
go_bind (EvBind _ (EvCoercion co)) = go co
go_bind (EvBind _ (EvId v)) = unitVarSet v
go_bind other = pprPanic "coVarsOfTcCo:Bind" (ppr other)
with this instead?
-- We expect only coercion bindings, so use evTermCoercion
go_bind :: EvBind -> VarSet
go_bind (EvBind _ tm) = go (evTermCoercion tm)
I think that'll fix it.
Simon
| -----Original Message-----
| From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-
| haskell-users-bounces@haskell.org] On Behalf Of Ganesh Sittampalam
| Sent: 22 August 2012 06:32
| To: glasgow-haskell-users@haskell.org
| Subject: 7.6.1 RC1 panic "coVarsOfTcCo:Bind"
|
| Hi,
|
| I'm getting the panic below when building darcs 2.8 with GHC 7.6. It'll
| take some effort to cut it down or give repro instructions for an
| uncut-down version (I needed to hack a lot of underlying packages to be
| able to even get as far as doing this build), so could someone confirm
| that it's worth it before I do so? I can't spot anything already
| reporting this in trac.
|
| Cheers,
|
| Ganesh
|
| ghc.exe: panic! (the 'impossible' happened)
| (GHC version 7.6.0.20120810 for i386-unknown-mingw32):
| coVarsOfTcCo:Bind
| cobox{v a6Czs} [lid]
| = cobox{v a6CTr} [lid] `cast`
| (