operate type piracy

[blegat]

These are type piracy as the ... could have no element.
https://github.com/JuliaOpt/MathOptInterface.jl/blob/ef83d2381b2e26a3e6466b8bc34b6687c7c20c61/src/Utilities/functions.jl#L904-L909
https://github.com/JuliaOpt/MathOptInterface.jl/blob/ef83d2381b2e26a3e6466b8bc34b6687c7c20c61/src/Utilities/functions.jl#L913-L915
To remove the type piracy, we should do f::ScalarLike{T}, g::ScalarLike{T}...