Re: [Nix-dev] Debugging a haskellPackages deep override gone wrong

Oh, I incorrectly assumed that the failure has anything to do with your overriding. But if you do $ nix-build -E "with (import {}); with haskell.lib; dontCheck (haskell.packages.ghc801.comonad)" that does fail in the same way, so in fact the overriding is not related at all to the issue your

Re: [Nix-dev] Debugging a haskellPackages deep override gone wrong

I have no knowledge of Nix internals. I wonder if it is possible to add a debug / tracing commands which will track source of the literal value or tuple? Even more awesome would be to have a data lineage for a tuple, which would contain original tuple location and all spots where this tuple was

Re: [Nix-dev] Debugging a haskellPackages deep override gone wrong

Oops, small to the code example: the line should be `let parent = (oldArgs.overrides or (_: _: {})) new old` (new instead of parent in the second to last word) Benno Fünfstück schrieb am So., 21. Feb. 2016 um 16:59 Uhr: > Hi Kosyrev, > > The problem here is most

Re: [Nix-dev] Debugging a haskellPackages deep override gone wrong

Hi Kosyrev, The problem here is most likely that ghcOrig is already passed an overrides argument, so you need to preserve the changes done by that: ghc = ghcOrig.override (oldArgs: { overrides = with haskell.lib; new: old: let parent = (oldArgs.overrides or (_: _: {})) parent old;