It seems like there are missing sparse matrix methods. In both 1.0.2 and 0.7 this code:

```
using SparseArrays
using LinearAlgebra
A = sprand(10,10,.9)
b_dense = Array(sprand(10,1,.8)) # works
b_sparse = sprand(10,1,.8) # doesn't work
x = A\b_dense # works
x = A\b_sparse # doesn't work
lu!(A) # gives an error
```

produces these errors:

`julia> x = A\b_sparse # error ERROR: MethodError: no method matching ldiv!(::SuiteSparse.UMFPACK.UmfpackLU{Float64,Int64}, ::SparseMatrixCSC{Float64,Int64})`

and

`ERROR: MethodError: no method matching lu!(::SparseMatrixCSC{Float64,Int64})`