ghc panic in deriving Generic1 on Array#
Compiling the following code
{-# Language DeriveGeneric, MagicHash #-}
module Test where
import GHC.Generics
import GHC.Prim
data Array a = Array (Array# a)
newtype Vec a = MkVec {unVec :: Array a} deriving Generic1
causes panic:
[1 of 1] Compiling Test ( Test.hs, Test.o )
ghc: panic! (the 'impossible' happened)
(GHC version 7.6.3 for x86_64-unknown-linux):
No match in record selector tyConTyVars
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
some comments from IRC:
<monoidal> with deriving Generic1 we get "Can't make a derived instance of `Generic1 Array': Array must not have unlifted or polymorphic arguments" - so it seems the check is not done recursively on used types <monoidal> * deriving Generic1 on Array
Trac metadata
Trac field | Value |
---|---|
Version | 7.6.3 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
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Blocking | |
CC | |
Operating system | |
Architecture |