Imported Upstream version 5.10.0.47

Former-commit-id: d0813289fa2d35e1f8ed77530acb4fb1df441bc0

mcs/tests/test-pattern-12.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+
+class X
+{
+	public static int Main ()
+	{
+		foreach (var x in Test1 ("2"))
+		{
+			Console.WriteLine (x);
+			return 1;
+		}
+
+		foreach (var x in Test2 (2))
+		{
+			Console.WriteLine (x);
+			return 2;
+		}
+
+		return 0;
+	}
+
+	public static IEnumerable<object> Test1 (object expr)
+	{
+		if (expr is short list)
+		{
+			yield return "list.Length";
+		}
+	}
+
+	public static IEnumerable<object> Test2 (object expr)
+	{
+		if (expr is string list)
+		{
+			yield return "list.Length";
+		}
+	}
+}