UnboxedTupleRep-related panic involving typeclasses
You can trigger a GHC panic by abusing UnboxedTupleRep in just the right way:
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE UnboxedTuples #-}
import GHC.Exts
class Wat (a :: TYPE 'UnboxedTupleRep)
deriving instance Wat (# a, b #)$ /opt/ghc/8.0.1/bin/ghc Bug.hs
[1 of 1] Compiling Bug ( Bug.hs, Bug.o )
ghc: panic! (the 'impossible' happened)
(GHC version 8.0.1 for x86_64-unknown-linux):
newTyConEtadArity (#,#)
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabugThis is probably a leak that #11723 (closed) didn't plug, as it only considered datatypes, not typeclasses.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 8.0.1 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | goldfire |
| Operating system | |
| Architecture |