Segfault due to levity polymorphism of mkWeak#

This code segfaults:

{-# LANGUAGE MagicHash, UnboxedTuples #-}
import GHC.Prim
import GHC.Types

main = do
    let local = ()
    let null = 0## :: Word#
    let triple = (# local, null, null #)
    IO (\s -> case mkWeakNoFinalizer# triple () s of (# s, r #) -> (# s, () #))

The problem is that mkWeakNoFinalizer# has a levity polymorphic type for its first argument, but the implementation really requires the first argument to be a pointer.

Trac metadata

Trac field	Value
Version	8.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	goldfire
Operating system
Architecture