Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

mcs/tests/test-599.cs

@@ -0,0 +1,50 @@
+using System;
+
+namespace Test
+{
+	using Text = System.Text;
+	using Str = System.String;
+	
+	public class String
+	{
+		string s;
+		public String(string s)
+		{
+			this.s=s;
+		}
+
+		public static implicit operator String (string s1) 
+		{
+			if(s1==null) return null;
+			return new String(s1);
+		}
+
+		public static implicit operator Str (String s1) 
+		{
+			if(s1==null) return null;
+			return s1.ToString();
+		}
+	}
+}
+
+namespace TestCompiler
+{
+	using String=Test.String;
+	
+	class MainClass
+	{
+		public static int Main ()
+		{
+			String a = "a";
+			int i=1;
+			a+=i;
+			string s = i + a;
+			
+			Console.WriteLine (s);
+			if (s != "1Test.String")
+				return 1;
+				
+			return 0;
+		}
+	}
+}