Imported Upstream version 5.10.0.78

Former-commit-id: 46737382176d7b811604042c613d5df6eef74f33

mcs/tests/test-readonly-03.cs

@@ -0,0 +1,16 @@
+// Compiler options: -langversion:latest
+using System;
+
+readonly struct S
+{
+	static S shared = new S ();
+
+	public S (int arg)
+	{
+		this = shared;
+	}
+
+	public static void Main ()
+	{
+	}
+}