Consider moving to Show-able functions once QuickCheck releases >2.15.0

[nwf]

QuickCheck has a notion of Show-able functions in Test.QuickCheck.Function. After the 2.15.0 release, the requisite constructor was exported, making these more useful as general-purpose objects. Consider moving the currently higher-order (that is, ->-bearing) MetaInfo ctors, https://github.com/lowRISC/QuickCheckVEngine/blob/ab924b4ac037b45fd182f11d2c1a7e079b1dcd0b/src/QuickCheckVEngine/TestTypes.hs#L66-L67 over to these once that's possible?

[PeterRugg]

Sounds good: I imagine that would tidy up MetaAssertLastVal which is already saved and restored in the traces IIRC. I imagine we'd need to introduce some constraints to MetaAssertCompound: presumably the Show can't cope with arbitrarily complex functions over sequences of unbounded length?

[nwf]

Yeah, MetaAssertCompound could be tricky. How would you feel about imposing the requirement that its ->s be static?