Difficulties with promoting numbers

[ChrisRackauckas]

@foobar_lv2

Unfortunately not: I use packages X and Y, not knowing about either MyPackage nor YourPackage, and the authors of X and Y know nothing about each other. X uses MyPackage, Y uses YourPackage, and I get into trouble.

No, then who wrote the YourNumber(5) + MyNumber(3)?

@foobar_lv2

A = Any; for i=1:10 push!(A, MyPackage.MyNumber(i)) end; for i=11:20 push!(A,YourPackage.YourNumber(i)) end;

Oh hey look, this code knows both numbers, so whoever wrote that knows both. To find an actual counter example, you’d have to write a code that never has both MyPackage and YourPackage in the same scope… otherwise yes, you can write code that doesn’t magically always work but that’s not surprising or non-local.