@@ -13437,3 +13437,42 @@ The implementation is based on `unordered-containers`.")
(description
"A sensible set of defaults for writing custom Preludes.")
(license license:expat)))
+
+(define-public ghc-mtl-compat
+ (package
+ (name "ghc-mtl-compat")
+ (version "0.2.1.3")
+ (source
+ (origin
+ (method url-fetch)
+ (uri (string-append
+ "https://hackage.haskell.org/package/mtl-compat/mtl-compat-"
+ version
+ ".tar.gz"))
+ (sha256
+ (base32
+ "15388p9ybdn6digk6cpdsw6havd0yva8vvwl3p7fnc9sb59wln34"))))
+ (build-system haskell-build-system)
+ (arguments
+ `(#:cabal-revision
+ ("4"
+ "1mfrx8cpx0502sjv0bmlfkl0h46c4krldg8m89k4fj6iawwg2ab5")
+ #:haddock?
+ #f))
+ (home-page
+ "https://github.com/haskell-compat/mtl-compat")
+ (synopsis
+ "Backported Control.Monad.Except module from mtl")
+ (description
+ "This package backports the Control.Monad.Except module from mtl
+(if using mtl-2.2.0.1 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.")
+ (license license:bsd-3)))