GHC panic when calling typeOf on a promoted data constructor
Here's what I did in GHCi to trigger the panic:
$ inplace/bin/ghc-stage2 --interactive
GHCi, version 8.1.20160101: http://www.haskell.org/ghc/ :? for help
λ> :set -XDataKinds
λ> :m Data.Typeable Data.Functor.Compose
λ> typeOf (Proxy :: Proxy 'Compose)
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 8.1.20160101 for x86_64-unknown-linux):
piResultTy
*
TYPE 'Lifted *
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabugEnabling -XPolyKinds doesn't trigger the error, though; #10343 (closed) will be triggered instead:
λ> :set -XPolyKinds
λ> typeOf (Proxy :: Proxy 'Compose)
<interactive>:5:1: error:
• No instance for (Typeable a0) arising from a use of ‘typeOf’
• In the expression: typeOf (Proxy :: Proxy Compose)
In an equation for ‘it’: it = typeOf (Proxy :: Proxy Compose)Trac metadata
| Trac field | Value |
|---|---|
| Version | 8.1 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | high |
| Resolution | Unresolved |
| Component | Compiler (Type checker) |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | goldfire |
| Operating system | |
| Architecture |
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