hmm.jl

using Base.Test

Base.hcat(Xin::Union{SparseVector, SparseMatrixCSC}...) = hcat(map(SparseMatrixCSC, Xin)...)
Base.vcat(Xin::Union{SparseVector, SparseMatrixCSC}...) = vcat(map(SparseMatrixCSC, Xin)...)
Base.hcat(Xin::Union{Vector, AbstractSparseVector}...) = hcat(map(sparse, Xin)...)
Base.vcat(Xin::Union{Vector, AbstractSparseVector}...) = vcat(map(sparse, Xin)...)

function Base.hcat(Xin::Union{Matrix, Vector, SparseMatrixCSC}...)
    X = SparseMatrixCSC[issparse(x) ? x : sparse(x) for x in Xin]
    hcat(X...)
end
function Base.vcat(Xin::Union{Matrix, Vector, SparseMatrixCSC}...)
    X = SparseMatrixCSC[issparse(x) ? x : sparse(x) for x in Xin]
    vcat(X...)
end

Base.hcat(A::Union{Matrix, Vector}...) = Base.typed_hcat(Base.promote_eltype(A...), A...)
Base.vcat{T}(A::Union{Matrix{T}, Vector{T}}...) = typed_vcat(T, A...)

Base.vcat(A::Union{Matrix, Vector}...) = Base.typed_vcat(Base.promote_eltype(A...), A...)
Base.hcat{T}(A::Union{Matrix{T}, Vector{T}}...) = typed_hcat(T, A...)

# Matrix vector cat not supported for sparse #13130 and #16661
@test issparse([sprand(10,10,.1) sprand(10,.1)])
@test issparse([sprand(10,1,.1); sprand(10,.1)])

@test issparse([sprand(10,10,.1) rand(10)])
@test issparse([sprand(10,1,.1)  rand(10)])
@test issparse([sprand(10,2,.1) sprand(10,1,.1) rand(10)])
@test issparse([sprand(10,1,.1); rand(10)])

@test issparse([sprand(10,.1)  rand(10)])
@test issparse([sprand(10,.1); rand(10)])

Hmm, it's the SparseVector, right? It's more specific, so it won't fall back to the abstractsparsevector method...