freer-simple fails to build on 9.6.0-alpha2 with a superclass error
See master ticket #22912 (closed)
Summary
When building the latest version package freer-simple
from Hackage on alpha2, it fails with a superclass error. Building on alpha1 has no problem. I guess this is due to !7050 (merged), but in my impression freer-simple
is a fairly popular package, so this could be a problem.
Steps to reproduce
cabal install freer-simple --allow-newer
Fails with:
Configuring library for freer-simple-1.2.1.2..
Preprocessing library for freer-simple-1.2.1.2..
Building library for freer-simple-1.2.1.2..
[ 1 of 14] Compiling Data.FTCQueue ( src/Data/FTCQueue.hs, dist/build/Data/FTCQueue.o, dist/build/Data/FTCQueue.dyn_o )
[ 2 of 14] Compiling Data.OpenUnion.Internal ( src/Data/OpenUnion/Internal.hs, dist/build/Data/OpenUnion/Internal.o, dist/build/Data/OpenUnion/Internal.dyn_o )
[ 3 of 14] Compiling Data.OpenUnion ( src/Data/OpenUnion.hs, dist/build/Data/OpenUnion.o, dist/build/Data/OpenUnion.dyn_o )
[ 4 of 14] Compiling Control.Monad.Freer.Internal ( src/Control/Monad/Freer/Internal.hs, dist/build/Control/Monad/Freer/Internal.o, dist/build/Control/Monad/Freer/Internal.dyn_o )
src/Control/Monad/Freer/Internal.hs:156:10: error: [GHC-39999]
• Could not deduce ‘Applicative b’
arising from the superclasses of an instance declaration
from the context: (MonadBase b m, LastMember m effs)
bound by the instance declaration
at src/Control/Monad/Freer/Internal.hs:156:10-69
Possible fix:
add (Applicative b) to the context of the instance declaration
• In the instance declaration for ‘MonadBase b (Eff effs)’
|
156 | instance (MonadBase b m, LastMember m effs) => MonadBase b (Eff effs) where
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
src/Control/Monad/Freer/Internal.hs:156:10: error: [GHC-39999]
• Could not deduce ‘Monad b’
arising from the superclasses of an instance declaration
from the context: (MonadBase b m, LastMember m effs)
bound by the instance declaration
at src/Control/Monad/Freer/Internal.hs:156:10-69
Possible fix:
add (Monad b) to the context of the instance declaration
• In the instance declaration for ‘MonadBase b (Eff effs)’
|
156 | instance (MonadBase b m, LastMember m effs) => MonadBase b (Eff effs) where
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Environment
- GHC version used: 9.6.0.20230128
Optional:
- Operating System: Arch Linux
- System Architecture: x64