Fallback for copying views into sparse matrices (#30895)

* Fallback for copying views into sparse matrices

* SparseArray --> SparseVecOrMat

* move copy method to sparsevector

* use the union explicitly

Author: mkborregaard

stdlib/SparseArrays/src/sparsevector.jl

@@ -700,6 +700,8 @@ function getindex(A::SparseMatrixCSC{Tv,Ti}, I::AbstractVector) where {Tv,Ti}
     SparseVector(n, rowvalB, nzvalB)
 end
 
+Base.copy(a::SubArray{<:Any,<:Any,<:Union{SparseVector, SparseMatrixCSC}}) = a.parent[a.indices...]
+
 function findall(x::SparseVector)
     return findall(identity, x)
 end