internal error (deriving generic / cyclical imports?)
|Reported by:||mf825||Owned by:|
|Operating System:||Linux||Architecture:||x86_64 (amd64)|
|Type of failure:||GHCi crash||Test Case:|
|Related Tickets:||7878, 8374||Differential Revisions:|
I often get compiler crashes in my larger and less well-maintained projects of this sort:
ghc: panic! (the 'impossible' happened)
(GHC version 7.6.3 for x86_64-unknown-linux):
tcIfaceGlobal (local): not found:
This happened on earlier 7.* ghc versions (debian 64bit), and from the counter-example I have condensed today my vague guess is that it has something to do with cyclical imports and -XDerivingGeneric or some other type system related language extension. I witnessed this in both ghc and ghci, but the counter-example is in ghci.
I want to investigate this further later, but in the hope that somebody can immediately see what's wrong, I decided to open this ticket with my preliminary findings.
Just unpack and run ./crash.sh. (Possibly you don't need to populate the sandbox and can crash it manually in your environment right away.)