Imported Upstream version 5.8.0.22

Former-commit-id: df344e34b07851d296efb3e6604c8db42b6f7aa3

mcs/errors/cs8139-4.cs

@@ -0,0 +1,20 @@
+// CS8139: `D.Prop': cannot change return type tuple element names when overriding inherited member `C.Prop'
+// Line: 14
+
+class C
+{
+	public virtual (int a, int b) Prop {
+		get {
+			throw null;
+		}
+	}
+}
+
+class D : C
+{
+	public override (int c, int d) Prop {
+		get {
+			throw null;
+		}
+	}	
+}