9.6.1 Macro-in-Macro

Build macros cannot be invoked from a macro context. This means it is impossible to use a macro to create a class which will provide build macros for other classes.

since Haxe 4.0.0

It is also disallowed to invoke expression macros in a macro context.

Trivia: Expression macro-in-macro

Prior to Haxe 4, using expression macros inside a macro context was possible. Support was primarily dropped because such code would cause issues with the compiler cache.