haskell.nix/docs/migrations.md

overlay to extras

overlay was renamed to extras in #79 to prevent confusion between the notion of nix overlays. Therefore plan-pkgs and stack-pkgs as generated by plan-to-nix and stack-to-nix will expose extras instead of overlay. Similarly mkStackPkgSet, mkPkgSet and mkCabalProjectPkgSet take a pkg-def-extras instead of pkg-def-overlay argument. If you are using iohk-nix, the iohk-overlay was parameter was renamed to iohk-extras.

Drop th-packages

When using iohk-nix to facility cross compilation, we used to require explicit listing of packages that required TemplateHaskell, this was dropped in iohk-nix@da7c1ed, see #92. As such the th-packages and nixpkgs argument were dropped from the iohk-module.