Over loaded strings test case

[Simon Marlow]

Ian Lynagh wrote:
> Hi Lennart,
> 
> I've applied all the overloaded-strings patches. Thanks!

Looks like there's one failure in nofib/spectral/power related to this:

==nofib== power: time to compile Main follows...
/playpen/ghc/nightly/HEAD-cam-02-unx/i386-unknown-linux/compiler/stage3/ghc-inplace 
-H16m -O -O -Rghc-timing -H32m -hisuf hi -c Main.hs -o Main.o

Main.hs:15:0:
     No instances for (IsString Double,
		      IsString Rational,
		      IsString Integer)
       arising from a 'default' declaration at Main.hs:15:0-34
     Possible fix:
       add an instance declaration for
       (IsString Double, IsString Rational, IsString Integer)
     when checking that each type in a default declaration
     is an instance of class Num

Cheers,
	Simon