{cpp} allows you to append a macro value onto the end of a string literal. Prior to {cpp}11, it was possible to do this either with or without a space between the two. But with the introduction of user-defined literals in {cpp}11, the preprocessing of string suffixes changed. To get the same string + macro behavior under {cpp} 11, you must separate the string literal and the macro with a space. Without the space, you'll get a compile error.
For the purpose of preparing for migration to {cpp}11, this rule raises an issue when there's no space between a string literal and a macro.
