error[E0658]: non-inline modules in proc macro input are unstable
 --> $DIR/mod_not_inlined.rs:2:1
  |
2 | mod foo;
  | ^^^^^^^^
  |
  = note: see issue #54727 <https://github.com/rust-lang/rust/issues/54727> for more information

error: Invalid pallet definition, expected mod to be inlined.
 --> $DIR/mod_not_inlined.rs:2:1
  |
2 | mod foo;
  | ^^^
