ghc-tasty depends via “inputs” on ghc-clock-bootstrap (v0.5) which is built without tests, while ghc-clock (v0.7) depends via “native-inputs” on ghc-tasty for tests.
This means that any package which depends on ghc-tasty and ghc-clock is potentially broken, e.g.: Warning: This package indirectly depends on multiple versions of the same package. This is very likely to cause a compile failure. package tasty (tasty-1.1.0.3-98rSghuW4l26JGzzQLN3ha) requires clock-0.5.1-KAiVgaxjUlIIuEB7RoOIe6 package hspec-core (hspec-core-2.5.5-BSfG8Pnx1al9rTpu1j0PaW) requires clock-0.7.2-JStwYFlKVmNHl0K1ll1Mx5 I’d suggest breaking the cycle instead by 1. introducing tasty-bootstrap which builds against the `time` module via the cabal flags: flag clock description: Depend on the clock package for more accurate time measurement default: True This could be done via (arguments `(#:configure-flags (“—flag=-clock”))) as far as I understand. 2. changing ghc-clock to test via tasty-bootstrap (and possibly some more variant testing packages that would be changed to depend on tasty-bootstrap) 3. changing tasty to test via ghc-clock. (I gave this approach a shot myself, but I’m running into mysterious silently hanging guild and guix build processes — possibly some cyclic dependencies which are noticed?)