Turn vector of matrices into a tuple?

[dkarrasch]

Have you considered making the type of the blocks field a Tuple{Vararg{AbstractMatrix}}? This would allow you to store the individual matrix types and make information available to the compiler.

julia> using LinearAlgebra, BlockDiagonals

julia> BlockDiagonal([rand(10,10), UpperTriangular(rand(10,10))])
20×20 BlockDiagonal{Float64,AbstractArray{Float64,2}}:

Note the AbstractArray type!