Imported Upstream version 5.10.0.47

Former-commit-id: d0813289fa2d35e1f8ed77530acb4fb1df441bc0

mcs/errors/cs8148-2.cs

@@ -0,0 +1,16 @@
+// CS8148: `B.Foo': must return by reference to match overridden member `A.Foo'
+// Line: 11
+
+public abstract class A
+{
+	public abstract ref int Foo { get; }
+}
+
+public class B : A
+{
+	public override long Foo {
+		get {
+			throw null;
+		}
+	}
+}