[Haskell-beginners] System.USB.writeInterrupt -- confused by error message from type system

[Brent Yorgey]

On Wed, Feb 27, 2013 at 09:06:30PM +0000, emacstheviking wrote:
> HURRAH! I have finally got it to compile...
> 
> I manually deleted the broken packages (I play too much anyway so a tidy up
> was in order) and it still failed with:
> 
> [1 of 1] Compiling Main             ( usb1.hs, usb1.o )
> 
> usb1.hs:64:28:
>     Couldn't match expected type
> `bytestring-0.9.2.1:Data.ByteString.Internal.ByteString'
>                 with actual type `ByteString'

Glad you got it to work!  For future reference, the fact that the
error message includes a package name and version number
(bytestring-0.9.2.1:Data.ByteString.Internal.ByteString instead of
just Data.ByteString.Internal.ByteString) is usually a very strong
indication that the real problem is multiple versions of the package
interfering with one another.

-Brent