Bad magic in static (FFI) object (7.6.1 for x86_64-apple-darwin)

When spraying HOC (Haskell to Objective-C) for bitrot, I encountered a GHC panic during the loading of some FFI.

Judging by the log below, it looks like this is during a TH execution, so the problem may be bitrot in this code wrt TH. Quite happy to dig further myself if pointed in the right direction.

Orac:~/work/hoc-read-only/hoc $ cabal build
Compiling HOC_cbits...
Building HOC-1.0...
Preprocessing library HOC-1.0...
[16 of 31] Compiling HOC.Invocation   ( HOC/HOC/Invocation.hs, dist/build/HOC/Invocation.o )

HOC/HOC/Invocation.hs:14:1:
    Unacceptable argument type in foreign declaration: FFICif
    When checking declaration:
      foreign import ccall safe "static Invocation.h callWithExceptions" c_callWithExceptions
        :: FFICif
           -> FunPtr a -> Ptr b -> Ptr (Ptr ()) -> IO (Ptr ObjCObject)
Orac:~/work/hoc-read-only/hoc $ cabal build
Compiling HOC_cbits...
Building HOC-1.0...
Preprocessing library HOC-1.0...
[ 7 of 31] Compiling HOC.FFICallInterface ( HOC/HOC/FFICallInterface.hs, dist/build/HOC/FFICallInterface.o )
[ 8 of 31] Compiling HOC.Arguments    ( HOC/HOC/Arguments.hs, dist/build/HOC/Arguments.o ) [HOC.FFICallInterface changed]
[11 of 31] Compiling HOC.CStruct      ( HOC/HOC/CStruct.hs, dist/build/HOC/CStruct.o ) [HOC.FFICallInterface changed]
[13 of 31] Compiling HOC.ID           ( HOC/HOC/ID.hs, dist/build/HOC/ID.o ) [HOC.FFICallInterface changed]
[16 of 31] Compiling HOC.Invocation   ( HOC/HOC/Invocation.hs, dist/build/HOC/Invocation.o )
[17 of 31] Compiling HOC.ExternFunctions ( HOC/HOC/ExternFunctions.hs, dist/build/HOC/ExternFunctions.o )

HOC/HOC/ExternFunctions.hs:77:34:
    Ambiguous occurrence `unsafePerformIO'
    It could refer to either `Foreign.unsafePerformIO',
                             imported from `Foreign' at HOC/HOC/ExternFunctions.hs:10:1-14
                          or `System.IO.Unsafe.unsafePerformIO',
                             imported from `System.IO.Unsafe' at HOC/HOC/ExternFunctions.hs:11:1-23
                             (and originally defined in `GHC.IO')
Orac:~/work/hoc-read-only/hoc $ cabal build
Compiling HOC_cbits...
Building HOC-1.0...
Preprocessing library HOC-1.0...
[17 of 31] Compiling HOC.ExternFunctions ( HOC/HOC/ExternFunctions.hs, dist/build/HOC/ExternFunctions.o )
[18 of 31] Compiling HOC.StdArgumentTypes ( HOC/HOC/StdArgumentTypes.hs, dist/build/HOC/StdArgumentTypes.o )
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package array-0.4.0.1 ... linking ... done.
Loading package deepseq-1.3.0.1 ... linking ... done.
Loading package containers-0.5.0.0 ... linking ... done.
Loading package pretty-1.1.1.0 ... linking ... done.
Loading package template-haskell ... linking ... done.
Loading package syb-0.3.7 ... linking ... done.
Loading package bytestring-0.10.0.0 ... linking ... done.
Loading package transformers-0.3.0.0 ... linking ... done.
Loading package mtl-2.1.2 ... linking ... done.
Loading package text-0.11.2.3 ... linking ... done.
Loading package parsec-3.1.3 ... linking ... done.
Loading package old-locale-1.0.0.5 ... linking ... done.
Loading package old-time-1.1.0.1 ... linking ... done.
Loading package fgl-5.4.2.4 ... linking ... done.
Loading package filepath-1.3.0.1 ... linking ... done.
Loading package time-1.4.0.1 ... linking ... done.
Loading package unix-2.6.0.0 ... linking ... done.
Loading package directory-1.2.0.0 ... linking ... done.
Loading package binary-0.5.1.1 ... linking ... done.
Loading package HUnit-1.2.5.1 ... linking ... done.
Loading object (static) dist/build/HOC_cbits.o ... ghc: dist/build/HOC_cbits.o: Bad magic. Expected: feedfacf, got: feedface.

ghc: panic! (the 'impossible' happened)
  (GHC version 7.6.1 for x86_64-apple-darwin):
	loadObj "dist/build/HOC_cbits.o": failed

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

Trac metadata

Trac field	Value
Version	7.6.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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