Panic on undersaturated keepAlive#
File:
{-# LANGUAGE MagicHash #-}
module T where
import GHC.Exts
f = keepAlive#
causes a panic:
<no location info>: error:
panic! (the 'impossible' happened)
GHC version 9.5.20220429:
invalid keepAlive# application
args: [app TYPE: 'Lifted, app TYPE: LiftedRep]
Call stack:
CallStack (from HasCallStack):
callStackDoc, called at compiler/GHC/Utils/Panic.hs:182:37 in ghc:GHC.Utils.Panic
pprPanic, called at compiler/GHC/CoreToStg/Prep.hs:1079:11 in ghc:GHC.CoreToStg.Prep
CorePrep assumes keepAlive#
is saturated but this is not checked.
NB: with ghci
, this fails Lint, but this is an independent bug #21415 (closed).