[GHC] #8281: The impossible happened: primRepToFFIType

[GHC]

#8281: The impossible happened: primRepToFFIType
-------------------------------------+-------------------------------------
        Reporter:  tibbe             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.4.1
       Component:  Compiler          |              Version:  7.6.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by winter):

 Replying to [comment:15 simonmar]:
 > @winter it's always wrong to pass an unpinned `ByteArray#` to a foreign
 call, regardless of whether the call is annotated as `safe` or `unsafe`,
 because GHC is free to implement an `unsafe` call as a `safe` call.
 Indeed we do this in GHCi.

 But lots of packages(text, for example) seems to be relying on this
 assumption, as you pointed out, text implemented its copy with FFI memcpy
 rather than a `copyByteArray#`.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8281#comment:18>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler