`M-x delete-trailing-whitespace` & `M-x untabify`

libraries/base/Control/Exception/Base.hs

libraries/base/Control/Monad.hs

libraries/base/Control/Monad/Fix.hs

libraries/base/Data/Data.hs

libraries/base/Data/Foldable.hs

libraries/base/Data/Functor.hs

libraries/base/Data/Maybe.hs

libraries/base/Data/OldTypeable/Internal.hs

libraries/base/Data/Typeable/Internal.hs

libraries/base/Data/Version.hs

libraries/base/Debug/Trace.hs

libraries/base/Foreign/C/Error.hs

libraries/base/Foreign/C/String.hs

libraries/base/Foreign/Marshal/Pool.hs

libraries/base/GHC/Base.lhs

libraries/base/GHC/Event/EPoll.hsc

libraries/base/GHC/Exts.hs

libraries/base/GHC/Foreign.hs

libraries/base/GHC/ForeignPtr.hs

libraries/base/GHC/Generics.hs