From 686ffdb98bab3e9a3db7c5654bcbf85ecf56cee7 Mon Sep 17 00:00:00 2001
From: Patrick Kofod Mogensen <patrick.mogensen@gmail.com>
Date: Tue, 14 Aug 2018 20:30:39 +0200
Subject: [PATCH] Keep parametric information when constructing a
 SparseMatrixCSC from a SparseMatrixCSC. (#28642)

---
 stdlib/SparseArrays/src/sparsematrix.jl | 1 +
 stdlib/SparseArrays/test/sparse.jl      | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/stdlib/SparseArrays/src/sparsematrix.jl b/stdlib/SparseArrays/src/sparsematrix.jl
index a88f27edd90d1..f954d33393d61 100644
--- a/stdlib/SparseArrays/src/sparsematrix.jl
+++ b/stdlib/SparseArrays/src/sparsematrix.jl
@@ -356,6 +356,7 @@ similar(S::SparseMatrixCSC, ::Type{TvNew}, ::Type{TiNew}, m::Integer, n::Integer
 
 
 # converting between SparseMatrixCSC types
+SparseMatrixCSC(S::SparseMatrixCSC) = copy(S)
 AbstractMatrix{Tv}(A::SparseMatrixCSC) where {Tv} = SparseMatrixCSC{Tv}(A)
 SparseMatrixCSC{Tv}(S::SparseMatrixCSC{Tv}) where {Tv} = copy(S)
 SparseMatrixCSC{Tv}(S::SparseMatrixCSC) where {Tv} = SparseMatrixCSC{Tv,eltype(S.colptr)}(S)
diff --git a/stdlib/SparseArrays/test/sparse.jl b/stdlib/SparseArrays/test/sparse.jl
index f88c6dde06493..0c17946d7a5d8 100644
--- a/stdlib/SparseArrays/test/sparse.jl
+++ b/stdlib/SparseArrays/test/sparse.jl
@@ -2289,4 +2289,10 @@ end
     @test adjoint(MC) == copy(adjoint(SC))
 end
 
+@testset "Issue #28634" begin
+    a = SparseMatrixCSC{Int8, Int16}([1 2; 3 4])
+    na = SparseMatrixCSC(a)
+    @test typeof(a) === typeof(na)
+end
+
 end # module