Simon Peyton Jones pushed to branch wip/T26548 at Glasgow Haskell Compiler / GHC Commits: 57dcbdf7 by Simon Peyton Jones at 2025-11-26T09:34:55+00:00 Try making Reduction strict in its Coercion Just an experiment. The comment says -- N.B. the 'Coercion' field must be lazy: see for instance -- GHC.Tc.Solver.Rewrite.rewrite_tyvar2 which returns an error in the 'Coercion' -- field when dealing with a Derived constraint (which is OK as this Coercion -- gets ignored later). We might want to revisit the strictness once Deriveds -- are removed. But Deriveds are in the rear view mirror. - - - - - 1 changed file: - compiler/GHC/Core/Reduction.hs Changes: ===================================== compiler/GHC/Core/Reduction.hs ===================================== @@ -94,7 +94,7 @@ but in fact `reductionOriginalType` is very seldom used, so it's not worth it. -- See Note [The Reduction type]. data Reduction = Reduction - { reductionCoercion :: Coercion + { reductionCoercion :: !Coercion , reductionReducedType :: !Type } -- N.B. the 'Coercion' field must be lazy: see for instance GHC.Tc.Solver.Rewrite.rewrite_tyvar2 View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/57dcbdf7cf9f0b443d5dd97c1603517e... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/57dcbdf7cf9f0b443d5dd97c1603517e... You're receiving this email because of your account on gitlab.haskell.org.