Hi *, I'm hoping someone could help me understand what the asserts in CoreToStg on line 240 and 216 are trying to tell me. I hit both of them while trying to compile libraries as dyn. WARNING: file compiler\stgSyn\CoreToStg.hs, line 250 $trModule2 False True ghc-stage1.exe: panic! (the 'impossible' happened) (GHC version 8.1.20160612 for x86_64-unknown-mingw32): ASSERT failed! file compiler\stgSyn\CoreToStg.hs line 216 $trModule2 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug WARNING: file compiler\simplCore\SimplCore.hs, line 633 Simplifier bailing out after 4 iterations [6737, 736, 51, 9] Size = {terms: 12,990, types: 9,998, coercions: 443} WARNING: file compiler\stgSyn\CoreToStg.hs, line 250 $fEqBigNat_$c/= False True ghc-stage1.exe: panic! (the 'impossible' happened) (GHC version 8.1.20160612 for x86_64-unknown-mingw32): ASSERT failed! file compiler\stgSyn\CoreToStg.hs line 240 [$fEqBigNat_$c/=, $fEqBigNat] Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug Kind Regards, Tamar