Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

mcs/tests/gtest-136.cs

@@ -0,0 +1,44 @@
+using System;
+
+namespace Martin {
+	public struct A
+	{
+		public readonly long Data;
+
+		public A (long data)
+		{
+			this.Data = data;
+		}
+
+		public static explicit operator B (A a)
+		{
+			return new B ((int) a.Data);
+		}
+	}
+
+	public struct B
+	{
+		public readonly int Data;
+
+		public B (int data)
+		{
+			this.Data = data;
+		}
+
+		public static implicit operator A (B b)
+		{
+			return new A (b.Data);
+		}
+	}
+
+	class X
+	{
+		public static void Main ()
+		{
+			B? b = new B (5);
+			A? a = b;
+			B? c = (B?) a;
+			B? d = (Martin.B?) a;
+		}
+	}
+}