class X::Syntax::Augment::WithoutMonkeyTyping does X::Syntax { }
Compile time error thrown when augment is used without use MONKEY-TYPING.
Since augment is considered a rather unsafe and impolite action, you have to pre-declare your intent with the use MONKEY-TYPING; pragma.
If you don't do that, like here
augment class Int { };
you get the error
===SORRY!=== augment not allowed without 'use MONKEY-TYPING'