Unitful and Plots, vector return types

[icweaver]

Leaving this here for future me once I forget about this again

Why? isa([(x,1),(y,1)], Array{Tuple{Stuff,Number},1}) = false

Covariance and etc. mean so many things outside computer science that it took me a while to get what people where saying here. I prefer to explain, probably not as comprehensively, but at least simply, by noting that: First, we have to differentiate two things: a) An array that can only contain numbers of type Float64 b) An array that can contain real numbers of different types (mixed Float64 and Int64, for example). Vectors of type (b) are not a subtype of vectors of type (a), of course, b…