diff --git a/jl/abstractarray.jl b/jl/abstractarray.jl
index 4fc5939403297..c317478e63cbb 100644
--- a/jl/abstractarray.jl
+++ b/jl/abstractarray.jl
@@ -328,7 +328,7 @@ function vcat{T}(V::AbstractVector{T}...)
     for Vk in V
         n += length(Vk)
     end
-    a = similar(V[1], n)
+    a = similar(full(V[1]), n)
     pos = 1
     for k=1:length(V)
         Vk = V[k]
@@ -438,7 +438,7 @@ function cat(catdim::Integer, X...)
     ndimsC = max(catdim, d_max)
     dimsC = ntuple(ndimsC, compute_dims)::(Int...)
     typeC = promote_type(map(x->isa(x,AbstractArray) ? eltype(x) : typeof(x), X)...)
-    C = similar(isa(X[1],AbstractArray) ? X[1] : [X[1]], typeC, dimsC)
+    C = similar(isa(X[1],AbstractArray) ? full(X[1]) : [X[1]], typeC, dimsC)
 
     range = 1
     for k=1:nargs
@@ -501,7 +501,7 @@ function cat(catdim::Integer, A::AbstractArray...)
     ndimsC = max(catdim, d_max)
     dimsC = ntuple(ndimsC, compute_dims)::(Int...)
     typeC = promote_type(map(eltype, A)...)
-    C = similar(A[1], typeC, dimsC)
+    C = similar(full(A[1]), typeC, dimsC)
 
     range = 1
     for k=1:nargs
diff --git a/jl/sparse.jl b/jl/sparse.jl
index e6785fa90ed56..2c95db52388eb 100644
--- a/jl/sparse.jl
+++ b/jl/sparse.jl
@@ -730,7 +730,7 @@ end
 
 # Sparse concatenation
 
-function vcat{Tv, Ti}(X::SparseMatrixCSC{Tv, Ti}...)
+function vcat(X::SparseMatrixCSC...)
     num = length(X)
     mX = [ size(x, 1) | x = X ] 
     nX = [ size(x, 2) | x = X ]
@@ -740,6 +740,9 @@ function vcat{Tv, Ti}(X::SparseMatrixCSC{Tv, Ti}...)
     end
     m = sum(mX)
 
+    Tv = promote_type(map(x->eltype(x.nzval), X)...)
+    Ti = promote_type(map(x->eltype(x.rowval), X)...)
+
     colptr = Array(Ti, n + 1)
     nnzX = [ nnz(x) | x = X ]
     nnz_res = sum(nnzX)
@@ -765,7 +768,7 @@ function vcat{Tv, Ti}(X::SparseMatrixCSC{Tv, Ti}...)
     SparseMatrixCSC(m, n, colptr, rowval, nzval)
 end
 
-function hcat{Tv, Ti}(X::SparseMatrixCSC{Tv, Ti}...)
+function hcat(X::SparseMatrixCSC...)
     num = length(X)
     mX = [ size(x, 1) | x = X ]
     nX = [ size(x, 2) | x = X ]
@@ -775,6 +778,9 @@ function hcat{Tv, Ti}(X::SparseMatrixCSC{Tv, Ti}...)
     end
     n = sum(nX)
 
+    Tv = promote_type(map(x->eltype(x.nzval), X)...)
+    Ti = promote_type(map(x->eltype(x.rowval), X)...)
+
     colptr = Array(Ti, n + 1)
     nnzX = [ nnz(x) | x = X ]
     nnz_res = sum(nnzX)
@@ -794,10 +800,10 @@ function hcat{Tv, Ti}(X::SparseMatrixCSC{Tv, Ti}...)
     SparseMatrixCSC(m, n, colptr, rowval, nzval)
 end
 
-function hvcat{Tv, Ti}(rows::(Int...), X::SparseMatrixCSC{Tv, Ti}...)
+function hvcat(rows::(Int...), X::SparseMatrixCSC...)
     nbr = length(rows)  # number of block rows
 
-    tmp_rows = Array(SparseMatrixCSC{Tv,Ti}, nbr)
+    tmp_rows = Array(SparseMatrixCSC, nbr)
     k = 0
     for i = 1 : nbr
         tmp_rows[i] = hcat(X[(1 : rows[i]) + k]...)
@@ -851,7 +857,7 @@ function _jl_spa_store_reset{T}(S::SparseAccumulator{T}, col, colptr, rowval, nz
         else
             offs += 1
         end
-        flags[i] = false
+        flags[pos] = false
     end
 
     colptr[col+1] = start + nvals
diff --git a/test/sparse.jl b/test/sparse.jl
index ac6c58af15057..07d2bd7ec310e 100644
--- a/test/sparse.jl
+++ b/test/sparse.jl
@@ -1,6 +1,40 @@
-s = speye(3)
-o = ones(3)
-@assert s * s == s
-@assert s \ o == o
-@assert [s s] == sparse([1, 2, 3, 1, 2, 3], [1, 2, 3, 4, 5, 6], ones(6))
-@assert [s; s] == sparse([1, 4, 2, 5, 3, 6], [1, 1, 2, 2, 3, 3], ones(6))
+# check matrix operations
+se33 = speye(3)
+@assert se33 * se33 == se33
+
+# check mixed sparse-dense matrix operations
+do33 = ones(3)
+@assert se33 \ do33 == do33
+
+# check horiz concatenation
+@assert [se33 se33] == sparse([1, 2, 3, 1, 2, 3], [1, 2, 3, 4, 5, 6], ones(6))
+
+# check vert concatenation
+@assert [se33; se33] == sparse([1, 4, 2, 5, 3, 6], [1, 1, 2, 2, 3, 3], ones(6))
+
+# check h+v concatenation
+se44 = speye(4)
+sz42 = spzeros(4, 2)
+sz41 = spzeros(4, 1)
+sz34 = spzeros(3, 4)
+se77 = speye(7)
+@assert [se44 sz42 sz41; sz34 se33] == se77
+
+# check concatenation promotion
+sz41_f32 = spzeros(Float32, 4, 1)
+se33_i32 = speye(Int32, 3, 3)
+@assert [se44 sz42 sz41_f32; sz34 se33_i32] == se77
+
+# check mixed sparse-dense concatenation
+sz33 = spzeros(3)
+de33 = eye(3)
+@assert  [se33 de33; sz33 se33] == full([se33 se33; sz33 se33 ])
+
+# check splicing + concatenation on
+# random instances, with nested vcat
+# (also side-checks sparse ref, which uses
+# sparse multiplication)
+for i = 1 : 10
+    a = sprand(5, 4, 0.5)
+    @assert [a[1:2,1:2] a[1:2,3:4]; a[3:5,1] [a[3:4,2:4]; a[5,2:4]]] == a
+end