I’m working on a GHC plugin (as part of my Haskell-to-hardware work) and running into trouble with coercions & roles. Error message from Core Lint:
Warning: In the expression: LambdaCCC.Lambda.lamvP# @ (GHC.Types.Bool → GHC.Types.Bool → GHC.Types.Bool → GHC.Types.Bool) @ (Simple.HasIf GHC.Types.Bool) "tpl"# ((LambdaCCC.Lambda.varP# @ (GHC.Types.Bool → GHC.Types.Bool → GHC.Types.Bool → GHC.Types.Bool) "tpl"#) `cast` (<LambdaCCC.Lambda.EP>_N (Sym (Simple.NTCo:HasIf[0] <GHC.Types.Bool>_N)) ∷ LambdaCCC.Lambda.EP (GHC.Types.Bool → GHC.Types.Bool → GHC.Types.Bool → GHC.Types.Bool) ~# LambdaCCC.Lambda.EP (Simple.HasIf GHC.Types.Bool))) Role incompatibility: expected nominal, got representationalin <LambdaCCC.Lambda.EP>_N (Sym (Simple.NTCo:HasIf[0] <GHC.Types.Bool>_N)) Do you see anything inconsistent/incompatible in the coercions or roles above? I constructed the nominal EP Refl coercion, and applied it (AppCo) an existing coercion of a simpler type. Thanks, -- Conal
_______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users