Resolving dependencies...
Configuring parsek-1.0.0...
Building parsek-1.0.0...
Preprocessing library parsek-1.0.0...
[1 of 3] Compiling Text.ParserCombinators.Class ( Text/ParserCombinators/Class.hs, dist/build/Text/ParserCombinators/Class.o )

Text/ParserCombinators/Class.hs:28:1:
    Non type-variable argument in the constraint: Eq (SymbolOf p)
    (Use FlexibleContexts to permit this)
    When checking that ‘char’ has the inferred type
      char :: forall (p :: * -> *).
              (Eq (SymbolOf p), Show (SymbolOf p), IsParser p) =>
              SymbolOf p -> p (SymbolOf p)
Failed to install parsek-1.0.0
cabal: Error: some packages failed to install:
parsek-1.0.0 failed during the building phase. The exception was:
ExitFailure 1