idris2 in nix develop shell searches for packages in home directory but should not

[michaelmesser]

$ nix develop                             
MacBook-Pro:IdrisNixTest michaelmesser$ idris2 --build mypkg.ipkg 
1/1: Building Main (src/Main.idr)
Error: Error in TTC
file: TTC data is in an newer format, file: /Users/michaelmesser/.idris2/idris2-0.5.1/prelude-0.5.1/Prelude.ttc, expected version: 71, actual version: 2022041300 (the most likely case is that the ./build directory in your current project contains files from a previous build of idris2 or the idris2 executable is from a different build than the installed .ttc files)