Agda needs an older version of haskell-equivalence

pkgs/development/libraries/haskell/equivalence/0.2.3.nix

@@ -0,0 +1,22 @@
+# This file was auto-generated by cabal2nix. Please do NOT edit manually!
+
+{ cabal, mtl, QuickCheck, STMonadTrans, testFramework
+, testFrameworkQuickcheck2
+}:
+
+cabal.mkDerivation (self: {
+  pname = "equivalence";
+  version = "0.2.3";
+  sha256 = "0dd986y0sn89fparyz6kz9yhzysbqjcp8s99r81ihghg7s9yc743";
+  buildDepends = [ mtl STMonadTrans ];
+  testDepends = [
+    mtl QuickCheck STMonadTrans testFramework testFrameworkQuickcheck2
+  ];
+  doCheck = false;
+  meta = {
+    homepage = "https://bitbucket.org/paba/equivalence/";
+    description = "Maintaining an equivalence relation implemented as union-find using STT";
+    license = self.stdenv.lib.licenses.bsd3;
+    platforms = self.ghc.meta.platforms;
+  };
+})