Resolving dependencies...
Configuring sorted-list-0.1.4.0...
Building sorted-list-0.1.4.0...
Preprocessing library sorted-list-0.1.4.0...
[1 of 1] Compiling Data.SortedList  ( Data/SortedList.hs, dist/build/Data/SortedList.o )

Data/SortedList.hs:265:12:
    Ambiguous occurrence ‘foldl’
    It could refer to either ‘List.foldl’,
                             imported from ‘Prelude’ at Data/SortedList.hs:(50,1)-(58,5)
                             (and originally defined in ‘GHC.List’)
                          or ‘Data.Foldable.foldl’,
                             imported from ‘Data.Foldable’ at Data/SortedList.hs:60:23-35
Failed to install sorted-list-0.1.4.0
cabal: Error: some packages failed to install:
sorted-list-0.1.4.0 failed during the building phase. The exception was:
ExitFailure 1