Compiling pandoc-188.8.131.52 on GHC HEAD panics (applyTypeToArgs)
Originally observed on a
head.hackage CI build here.
Attempting to compile
pandoc-184.108.40.206 on GHC HEAD will result in the following panic:
[106 of 166] Compiling Text.Pandoc.Writers.Docx ghc: panic! (the 'impossible' happened) (GHC version 220.127.116.1100403: applyTypeToArgs Expression: wild_a3j6U ys_a1Q2 Type: Element Args: [ys_a1Q2] Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1228:37 in ghc:Outputable pprPanic, called at compiler/GHC/Core/Utils.hs:237:14 in ghc:GHC.Core.Utils
Unfortunately, the code that triggers the panic is quite massive, and I have had no luck attempting to minimize it. I did confirm that the commit that caused this regression is b943b25d (
Re-engineer the binder-swap transformation), however.