"Recursive expansion of macro"?

Development Macros
1

I have a macro that, when applied to a type, applies the same macro to nested types. E.g.,

@MyMacro
struct Foo {
  struct Bar {
  }
}

Should expand to:

-@MyMacro
 struct Foo {
+  @MyMacro
   struct Bar {
   }
 }

And so on.

Using a member attribute macro would seem to make this straightforward, but I get a "Recursive expansion of macro" error. I can see wanting some limitation on recursion to prevent the compiler from going into a tailspin, but it seems like it should work at some limited capacity.

Is this a bug worth filing or is this limitation by design?

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2

I'm having this issue, despite my nested macro only being applied one layer down like in your example.

Did you find a workaround / solution to this?

3

It's not pretty, but you could alias @MyMacro to @MyMacro2 and so on and apply them with an incremented number at each layer.

2 Likes