warning: non-local `macro_rules!` definition, they should be avoided as they go against expectation
  --> $DIR/non_local_defs.rs:9:1
   |
LL | macro_rules! a_macro { () => {} }
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: remove the `#[macro_export]` or make this doc-test a standalone test with its own `fn main() { ... }`
   = note: a `macro_rules!` definition is non-local if it is nested inside an item and has a `#[macro_export]` attribute
   = note: one exception to the rule are anon-const (`const _: () = { ... }`) at top-level module
   = note: this lint may become deny-by-default in the edition 2024 and higher, see the tracking issue <https://github.com/rust-lang/rust/issues/120363>
   = note: `#[warn(non_local_definitions)]` on by default

warning: 1 warning emitted