Hi all, I went into the rabbit hole that starts here https://ghc.haskell.org/trac/ghc/ticket/11501 So far I know that: 1. fibon is not built regularly by any CI and it bitrotted significantly. 2. Makefile's for fibon use undefined variables like INPLACE_HSC2HS_PGM. Probably those were sourced from ghc/mk/*.mk, but not now. 3. Haskell courses are pre-AMP (this is easiest to fix). 4. Makefile's build object files one by one and that fails in case modules depend on each other. ghc-paths.mk sorts objects and that gives wrong compile order. Does anybody know a commit-hash or date when it did compile last time? Knowing that this module (fibno) wasn't used for so long does it make sense to fix it? How about removing it? -- Gracjan