error: macro expansion ignores expression `2` and any tokens following
  --> $DIR/trait-non-item-macros.rs:3:9
   |
LL |         $a
   |         ^^
...
LL |     bah!(2);
   |     ------- caused by the macro expansion here
   |
   = note: the usage of `bah!` is likely invalid in trait item context

error[E0308]: mismatched types
  --> $DIR/trait-non-item-macros.rs:12:33
   |
LL |     let _recovery_witness: () = 0;
   |                            --   ^ expected `()`, found integer
   |                            |
   |                            expected due to this

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0308`.