diff --git a/overlays/haskell.nix b/overlays/haskell.nix
index 7671866b7..2000f47e8 100644
--- a/overlays/haskell.nix
+++ b/overlays/haskell.nix
@@ -827,10 +827,11 @@ final: prev: {
             #     ];
             #   }
             #
-            shellFor = extraArgs: shellFor' (rawProject.args.shell // extraArgs).crossPlatforms extraArgs;
-            shellFor' = crossPlatforms: extraArgs:
+            shellFor = extraArgs: (appendModule { shell = extraArgs; }).shell;
+            shell = shellFor' rawProject.args.shell.crossPlatforms;
+            shellFor' = crossPlatforms:
               let
-                shellArgs = builtins.removeAttrs (rawProject.args.shell // extraArgs) [ "crossPlatforms" ];
+                shellArgs = builtins.removeAttrs rawProject.args.shell [ "crossPlatforms" ];
                 # These are the args we will pass to the shells for the corss compiler
                 argsCross =
                   # These things should match main shell
@@ -848,9 +849,6 @@ final: prev: {
                   inputsFrom = shellArgs.inputsFrom or [] ++ crossShells;
                 });
 
-            # Default shell
-            shell = shellFor {};
-
             # Like `.hsPkgs.${packageName}` but when compined with `getComponent` any
             # cabal configure errors are defered until the components derivation builds.
             getPackage = packageName:
diff --git a/test/cabal.project.local b/test/cabal.project.local
index d3e73d819..5c36c9fe2 100644
--- a/test/cabal.project.local
+++ b/test/cabal.project.local
@@ -1,3 +1,10 @@
+-- See https://github.com/haskellari/splitmix/pull/97
+source-repository-package
+  type: git
+  location: https://github.com/hamishmack/splitmix.git
+  tag: e3549473b124a7ba078408ac0d2c8aa8111c3888
+  --sha256: sha256-o18DEF4+z3/jGhMZbow8PFtYBiIm6+b4B+6o5tM6ez0=
+
 if impl(ghc>=9.12.1)
   -- allow newer packages, that are bound to be newer due to
   -- being shipped with a newer compiler.  If you extend this