Illegal back-quote delimiter '`'
It is possible to specify a string literal other than with double quotation marks. You can use the back quote and then enclose the string by using any character that is not a space. CS1539 is generated when you use a space to delimit a string after a back quote.
The following sample generates CS1539:
using System; public class MyClass { public static void Main() { string s = ` j ; // CS1539 // try the following line instead // string s = `[j]; Console.WriteLine(s); } }