Avoid piracy

[aplavin]

StaticArrays does some piracy, at least in similar():

StaticArrays.jl/src/abstractarray.jl

Lines 141 to 146 in 07c1245

	const HeterogeneousBaseShape = Union{Integer, Base.OneTo}
	const HeterogeneousShape = Union{HeterogeneousBaseShape, SOneTo}
	const HeterogeneousShapeTuple = Tuple{Vararg{HeterogeneousShape}}
	similar(A::AbstractArray, ::Type{T}, shape::HeterogeneousShapeTuple) where {T} = similar(A, T, homogenize_shape(shape))
	similar(::Type{A}, shape::HeterogeneousShapeTuple) where {A<:AbstractArray} = similar(A, homogenize_shape(shape))

Here,

HeterogeneousShapeTuple = Tuple{Vararg{Union{Integer, Base.OneTo, SOneTo} }} 

and it fits eg Tuple{}, Tuple{Int}, Tuple{Int, Int}.

It's generally a good thing to avoid piracy in foundational packages. Maybe, also related to ambiguities like JuliaArrays/StructArrays.jl#279?..

[jishnub]

Strictly speaking, this isn't piracy, as the narrower method is defined in Base. It would be good to remove this, though, if possible

[mateuszbaran]

It would be great if we actually had non-ambiguous documentation about what is and what isn't type piracy so that we can be sure what is and what is not wrong, ref. JuliaLang/julia#51669 . Currently there seems to be no consensus nor clear communication from core Julia devs regarding this "wider union" case.