This happened twice now in a short time. Compare:
Should there be a warning in the docs? Like, for example, here:
https://docs.julialang.org/en/v1/manual/arrays/#man-array-literals
Something along the lines of:
"Remember, promotion to a common type may also change the type of nested arrays:
julia> arr = [Int[1,2],[]]
3-element Array{Array{Any,1},1}:
[1, 2]
[]
julia> arr[1]
2-element Array{Any,1}:
1
2
To prevent this, declare an abstract type for the containing array:
julia> arr2 = Any[[1,2],[]]
3-element Array{Any,1}:
[1, 2]
Any[]
julia> arr2[1]
2-element Array{Int64,1}:
1
2
"