Using a macro in a character class produces the error message “Macros in character classes are not supported.” This contradicts the documentation:

CharClassContent    ::= CharClass | Character |
                        Character'-'Character | 
                        MacroUsage | PredefinedClass

a character class [...] matches any character in that class. A Character is considered an element of a class if it is listed in the class or if its code lies within a listed character range Character’-’Character or Macro or predefined character class.