This package backports the "Control.Monad.Except" module from
@mtl@ (if using @mtl-22.214.171.124@ or earlier), which reexports the
@ExceptT@ monad transformer and the @MonadError@ class.
This package should only be used if there is a need to use the
@Control.Monad.Except@ module specifically. If you just want
the @mtl@ class instances for @ExceptT@, use
@transformers-compat@ instead, since @mtl-compat@ does nothing
but reexport the instances from that package.
Note that unlike how @mtl-2.2@ or later works, the
"Control.Monad.Except" module defined in this package exports
all of @ExceptT@'s monad class instances. Therefore, you may
have to declare @import Control.Monad.Except ()@ at the top of
your file to get all of the @ExceptT@ instances in scope.