25 Mar
2026
25 Mar
'26
12:53 p.m.
Friends After 10 days of working on !15719 I have suddenly started getting /home/simonpj/code/HEAD-19/libraries/ghc-boot-th-next/../ghc-internal/src/GHC/Internal/Classes.hs:10:17: error: [GHC-04924] Unknown flag in {-# OPTIONS_GHC #-} pragma: -fdefines-known-key-names | 10 | {-# OPTIONS_GHC -fdefines-known-key-names #-} | ^^^^^^^^^^^^^^^^^^^^^^^^^ I have no idea why this was fine until 10am this morning, and has suddenly started happening now. *How does GHC decide what runtime flags it allows? * `-fdefines-known-key-names` is in GHC.Driver.Session.fFlagsDeps. I'm boggled that it worked until 10am and then abruptly stopped. Any advice? Simon