Hello Simon,
On Mon, 15 Apr 2019 at 23:14, Simon Peyton Jones via ghc-devs
It is terribly mysterious that “cabal install hspec” doesn’t, well, install hspec.
In the cabal v2-* model [1] installing libraries globally is no longer the recommended mode of operation, which is why you now need to pass --lib to 'install' to do that. There are now better alternatives for most use cases of 'install --lib': * For just trying out some set of libraries in REPL, you can use `cabal new-repl --build-depends=foo,bar,baz` outside of a project instead of ghci. [2] If you have .ghc.environment file generation turned on, you can also use plain ghci inside your project, and it will pick up the project context. [3] * For running Haskell scripts that expect extra libraries in the global package DB you can use `#! cabal` instead of `#! runghc`. [4]
It must surely be a bug that “cabal install –lib hspec” simply crashes.
This is a bug that we haven't fixed yet [5]. Should've just worked. [1] https://cabal.readthedocs.io/en/latest/nix-local-build-overview.html [2] https://cabal.readthedocs.io/en/latest/nix-local-build.html#cabal-v2-repl [3] https://cabal.readthedocs.io/en/latest/nix-local-build.html#cfg-field-write-... [4] https://cabal.readthedocs.io/en/latest/nix-local-build.html#cabal-v2-run [5] https://github.com/haskell/cabal/issues/5990