| error: macro expansion ignores `expr` metavariable 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`. |