Friends I'm trying to repro #25064 with my development build of GHC. The test case depends on packages `primitive` and `hashtables`. So I try this (see below). Alas, apparently after the `cabal install`, it can't find Prelude. What should I do? I tried removing the "environments" file, whatever that is, which then meant it could find Prelude -- but the libraries were no longer installed. I lack a decent model of what is going on with installing packages for my development builds. Is there a write up anywhere? Thanks Simon bash$ cabal install --lib hashtables primitive --with-compiler $HOME/code/HEAD/$s2 Warning: Unknown/unsupported 'ghc' version detected (Cabal 3.10.1.0 supports 'ghc' version < 9.8): /home/simonpj/code/HEAD/_build/stage1/bin/ghc is version 9.11.20240517 Warning: Unknown/unsupported 'ghc' version detected (Cabal 3.10.1.0 supports 'ghc' version < 9.8): /home/simonpj/code/HEAD/_build/stage1/bin/ghc is version 9.11.20240517 Resolving dependencies... bash$ ~/code/HEAD/$s2 -c T25064.hs Loaded package environment from T25064.hs:1:8: error: [ ]8;;https://errors.haskell.org/messages/GHC-87110 \GHC-87110 ]8;; \] Could not load module ‘Prelude’. It is a member of the hidden package ‘base-4.20.0.0’. Use -v to see a list of the files searched for. | 1 | module Bug where | ^^^ bash$ rm /home/simonpj/.ghc/x86_64-linux-9.11.20240517/environments/default bash$ ~/code/HEAD/$s2 -c T25064.hs T25064.hs:3:1: error: [ ]8;;https://errors.haskell.org/messages/GHC-61948 \GHC-61948 ]8;; \] Could not find module ‘Control.Monad.Primitive’. Perhaps you meant Control.Monad.Writer (from mtl-2.3.1) Use -v to see a list of the files searched for. | 3 | import Control.Monad.Primitive | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ T25064.hs:4:1: error: [ ]8;;https://errors.haskell.org/messages/GHC-87110 \GHC-87110 ]8;; \] Could not find module ‘Data.HashTable.ST.Basic’. Use -v to see a list of the files searched for. | 4 | import qualified Data.HashTable.ST.Basic as H | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^