unsafeCoerce of data constructor application results in invalid code generation
@RyanGlScott noticed that a program using his parameterized-utils
library crashes reliably in all GHC versions from 8.6 to 9.0.1 and helpfully produced a minimal reproducer ($2777). Specifically compiling and running this program under -O0
results in a runtime error:
hi: internal error: stg_ap_pp_ret
(GHC version 9.0.1 for x86_64_unknown_linux)
Please report this as a GHC bug: https://www.haskell.org/ghc/reportabug
Aborted (core dumped)
Running with -O2
prints an different result depending upon which GHC version is used.