segfault when ignoring invalid byte sequence when decoding UTF8//IGNORE

The code below segfaults on a variety of platforms and GHC versions - I've tried 7.4.1 and 7.6.1, on Windows and Linux.

It seems to be related to (a) the specific choice of UTF8 - doesn't happen with UTF16 or UTF32 etc and (b) having the invalid byte sequence at the end of the thing being decoded.

import qualified Data.ByteString as B
import System.IO

tempFile = "temp"

main = do
   utf8Ignore <- mkTextEncoding "UTF8//IGNORE"
   B.writeFile tempFile (B.pack [128])
   h <- openFile tempFile ReadMode
   hSetEncoding h utf8Ignore
   hGetContents h >>= putStrLn

Trac metadata

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