Add char to types resolvable by GenericZero

[Happypig375]

It's resolvable by GenericOne already. Why not add it to GenericZero?

[cartermp]

Needs a @dsyme review since I don't have context on this omission

[dsyme]

This is by design, though I don't feel strongly about it - the rationale is

1. if you really want a numeric type you should use UInt16.

2. The One on char is only supported to allow addition in the range operator for x in 'a' .. 'z' do ...

Is there an example which shows the good reason to support Zero on Char?

See also ConstraintSolver.fs, which would also need updating, and we would need testing of course.

 // We pretend for uniformity that the numeric types have a static property called Zero and One // As with constants, only zero is polymorphic in its units
| [], [ty], false, "get_Zero", [] when IsNumericType g ty -> do! SolveTypeEqualsTypeKeepAbbrevs csenv ndeep m2 trace rty ty
return TTraitBuiltIn
| [], [ty], false, "get_One", [] when IsNumericType g ty || isCharTy g ty -> do! SolveDimensionlessNumericType csenv ndeep m2 trace ty do! SolveTypeEqualsTypeKeepAbbrevs csenv ndeep m2 trace rty ty
return TTraitBuiltIn

[Happypig375]

It's mostly for consistency. It is weird to have GenericOne supported but not GenericZero since char does have a zero value.

[dsyme]

It's mostly for consistency. It is weird to have GenericOne supported but not GenericZero since char does have a zero value.

Can you add the fix to ConstraintSolver.fs too, and also add test cases? Thanks

[cartermp]

Thanks @Happypig375, I think this is a good change.

[KevinRansom]

Thank you for this contribution

[KevinRansom]

@Happypig375 thank you for this contribution.

Kevin