Moritz Angermann

@blaggacao I'm afraid that has no effect :-/

For reference, this is the error 9.2.4 provides: ``` src/Ouroboros/Network/Testing/ConcreteBlock.hs:124:10: error: • Non type-variable argument in the constraint: Hashable (HeaderHash b) (Use FlexibleContexts to permit this) • In the instance...

Uhh Oh, that's not good.

We've added the following patch: https://github.com/input-output-hk/ouroboros-network/pull/1423/files#diff-b6eac6cb1f63c584aee3e94132101030, and I believe we should do the following: - [ ] upstream it to ghc. - [ ] add it to our overlays, so...

@ttuegel > I think hsc2hs should be bundled with GHC, isn't that right? This is correct. With `haskell.nix` we try to rely as little on stuff that ghc is supposed...

@kaldonir ohh. That's missing the curly braces :( It should be `modules = [{ ... }]`. In general you can juse all kinds of options you'd like to change. The...

I think `nix-instantiate` would have to, but I'm not sure it lists it. I believe that using cachix with the `--watch-store` option is the best solution: ``` cachix push $cache...

The excessive `ghc-pkg` invocations would be another item to look into. Ideally we’d cache the unit-ids in nix and wouldn't have to call `ghc-pkg` that often. It would certainly be...

@purefn I'm afraid I don't know how about profiling tools :-/ We basically call `ghc-pkg` a lot in this: https://github.com/input-output-hk/haskell.nix/blob/5fa379ebc75c6f960d9f03aa857c0e0350e4dbe1/builder/make-config-files.nix#L9-L36 thus if we could stick the `id` and `name` somehow...

So we know that we spend about 90/150 or 3/5 in https://github.com/input-output-hk/haskell.nix/blob/5fa379ebc75c6f960d9f03aa857c0e0350e4dbe1/builder/make-config-files.nix#L46 That seems quite extreme! I believe it would be quite helpful to know how much time we spend...