Resolving dependencies...
Downloading splay-0.0.1...
Configuring splay-0.0.1...
Building splay-0.0.1...
Preprocessing library splay-0.0.1...
[1 of 2] Compiling Data.Splay.Internal ( src/Data/Splay/Internal.hs, dist/build/Data/Splay/Internal.o )
[2 of 2] Compiling Data.Splay       ( src/Data/Splay.hs, dist/build/Data/Splay.o )

src/Data/Splay.hs:33:7:
    Not in scope: type constructor or class ‘Monoid’
    Perhaps you meant ‘Monad’ (imported from Prelude)

src/Data/Splay.hs:38:18: Not in scope: ‘mempty’

src/Data/Splay.hs:52:24: Not in scope: ‘mempty’

src/Data/Splay.hs:126:20: Not in scope: ‘mempty’

src/Data/Splay.hs:127:15: Not in scope: ‘mempty’
Failed to install splay-0.0.1
cabal: Error: some packages failed to install:
splay-0.0.1 failed during the building phase. The exception was:
ExitFailure 1