``` using SparseArrays C = spzeros(2,2) C[1,1] = 0.0 ``` [does not add](https://github.com/JuliaLang/julia/blob/b1ceadc524e507f466e00681df6e8bca652dba53/stdlib/SparseArrays/src/sparsematrix.jl#L2497) an entry to the sparse matrix. Neither should: ``` using ExtendableSparse A = ExtendableSparseMatrix(2, 2) A[1,1] = 0.0 ``` but it does.