diff --git a/pkgs/development/haskell-modules/make-package-set.nix b/pkgs/development/haskell-modules/make-package-set.nix
index 95dac230cc55..3f339030de55 100644
--- a/pkgs/development/haskell-modules/make-package-set.nix
+++ b/pkgs/development/haskell-modules/make-package-set.nix
@@ -159,6 +159,13 @@ let
         # Generated from ${src}
         ${orig.preConfigure or ""}
       '';
+      passthru = orig.passthru or {} // {
+        # When using callCabal2nix or callHackage, it is often useful
+        # to debug a failure by inspecting the Nix expression
+        # generated by cabal2nix. This can be accessed via this
+        # cabal2nixDeriver field.
+        cabal2nixDeriver = src;
+      };
     });
 
 in package-set { inherit pkgs stdenv callPackage; } self // {