1 files changed, 95 insertions, 0 deletions
diff --git a/tests/src/JIT/Regression/JitBlue/Runtime_1241/Runtime_1241.cs b/tests/src/JIT/Regression/JitBlue/Runtime_1241/Runtime_1241.cs
new file mode 100644
index 0000000000..02c21ce5eb
--- /dev/null
+++ b/tests/src/JIT/Regression/JitBlue/Runtime_1241/Runtime_1241.cs
@@ -0,0 +1,95 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Linq;
+using System.Numerics;
+using System.Runtime.CompilerServices;
+
+namespace Runtime_1241
+{
+
+    public struct Vertex
+    {
+        public Vector3 Position;
+        public Vector2 TexCoords;
+
+        public Vertex(Vector3 pos, Vector2 tex)
+        {
+            Position = pos;
+            TexCoords = tex;
+        }
+    }
+
+    class Program
+    {
+        static int Main()
+        {
+            int returnVal = 100;
+
+            // This prints all zeros in the failure case.
+            Console.WriteLine("Replacing array element with new struct directly");
+            {
+                var bug = Bug.Create();
+                bug.MutateBroken();
+
+                Console.WriteLine(bug.Vertices[0].Position);
+                if ((bug.Vertices[0].Position.X != 1) || (bug.Vertices[0].Position.Y != 1) || (bug.Vertices[0].Position.Z != 1))
+                {
+                    returnVal = -1;
+                }
+            }
+
+            // Works
+            Console.WriteLine("Replacing array element with new struct, stored in a local variable first");
+            {
+                var bug = Bug.Create();
+                bug.MutateWorks();
+
+                Console.WriteLine(bug.Vertices[0].Position);
+                if ((bug.Vertices[0].Position.X != 1) || (bug.Vertices[0].Position.Y != 1) || (bug.Vertices[0].Position.Z != 1))
+                {
+                    returnVal = -1;
+                }
+            }
+
+            return returnVal;
+        }
+    }
+
+    public class Bug
+    {
+        public static Bug Create()
+        {
+            return new Bug
+            {
+                Vertices = Enumerable.Range(1, 100).Select(i => new Vertex(new Vector3(i), Vector2.One)).ToArray()
+            };
+        }
+
+        public Vertex[] Vertices { get; set; }
+
+        public void MutateBroken()
+        {
+            for (var i = 0; i < Vertices.Length; i++)
+            {
+                var vert = Vertices[i];
+
+                Vertices[i] = new Vertex(vert.Position, vert.TexCoords);
+            }
+        }
+
+        public void MutateWorks()
+        {
+            for (var i = 0; i < Vertices.Length; i++)
+            {
+                var vert = Vertices[i];
+
+                var newVert = new Vertex(vert.Position, vert.TexCoords);
+
+                Vertices[i] = newVert;
+            }
+        }
+    }
+}