1 error[E0308]: mismatched types
2 --> $DIR/issue-29084.rs:4:13
5 | ^^^^^^^ expected `u8`, found `&mut u8`
8 | --------- in this macro invocation
10 = note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
12 error: aborting due to previous error
14 For more information about this error, try `rustc --explain E0308`.