From ef2272f2e1084acc43039c739fe19a55caee2188 Mon Sep 17 00:00:00 2001
From: Martin Raum <martin@raum-brothers.eu>
Date: Thu, 3 Dec 2020 17:28:07 +0100
Subject: [PATCH 1/2] fix aliasing in matrix algebra constructor

---
 src/generic/MatrixAlgebra.jl       | 2 +-
 test/generic/MatrixAlgebra-test.jl | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/generic/MatrixAlgebra.jl b/src/generic/MatrixAlgebra.jl
index 42a3efcbbc..69a2be204d 100644
--- a/src/generic/MatrixAlgebra.jl
+++ b/src/generic/MatrixAlgebra.jl
@@ -598,7 +598,7 @@ function (a::MatAlgebra{T})(b::S) where {S <: RingElement, T <: RingElement}
          if i != j
             entries[i, j] = zero(R)
          else
-            entries[i, j] = rb
+            entries[i, j] = i == 1 ? rb : deepcopy(rb)
          end
       end
    end
diff --git a/test/generic/MatrixAlgebra-test.jl b/test/generic/MatrixAlgebra-test.jl
index 4d090c7a86..1d465c31fa 100644
--- a/test/generic/MatrixAlgebra-test.jl
+++ b/test/generic/MatrixAlgebra-test.jl
@@ -27,6 +27,7 @@ end
    f = S(t^2 + 1)
 
    @test isa(f, MatAlgElem)
+   @test !(f[1,1] === f[2,2])
 
    g = S(2)
 

From 414553f05b380ea9440e274aa4820d9795171da0 Mon Sep 17 00:00:00 2001
From: Martin Raum <martin@raum-brothers.eu>
Date: Thu, 3 Dec 2020 21:06:45 +0100
Subject: [PATCH 2/2] fix alising also for matrix spaces

---
 src/generic/Matrix.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/generic/Matrix.jl b/src/generic/Matrix.jl
index de7ca3454c..7df99310a5 100644
--- a/src/generic/Matrix.jl
+++ b/src/generic/Matrix.jl
@@ -5856,7 +5856,7 @@ function (a::MatSpace{T})(b::S) where {S <: RingElement, T <: RingElement}
          if i != j
             entries[i, j] = zero(R)
          else
-            entries[i, j] = rb
+            entries[i, j] = i == 1 ? rb : deepcopy(rb)
          end
       end
    end