stage2 build fails

Simon Peyton Jones simonpj at
Sat Jan 25 20:26:29 UTC 2020

I'm getting this with "sh validate -legacy"

compiler/main/DynFlags.hs:1344:15: error: [-Woverlapping-patterns, -Werror=overlapping-patterns]

    Pattern match is redundant

    In an equation for 'settings': settings s | otherwise = ...


1344 |             | otherwise = panic $ "Invalid cfg parameters." ++ exampleString

     |               ^^^^^^^^^
This is when compiling the stage-2 compiler.  There's an ifdef in DynFlags thus

#if __GLASGOW_HASKELL__ <= 810

            | otherwise = panic $ "Invalid cfg parameters." ++ exampleString

but somehow it's not triggering for the stage2 compiler.
Any ideas?  It's blocking a full build.
This #ifdef was added in 8038cbd96f4, when GHC became better at reporting redundant code.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the ghc-devs mailing list