error[E0426]: use of undeclared label `'a` --> $DIR/label_break_value_invalid.rs:6:19 | LL | break 'a $val; | ^^ undeclared label `'a` ... LL | mac2!(2); | -------- in this macro invocation | = note: this error originates in the macro `mac2` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0426]: use of undeclared label `'a` --> $DIR/label_break_value_invalid.rs:28:19 | LL | let x: u8 = mac3!('b: { | -- a label with a similar name is reachable LL | if true { LL | break 'a 3; | ^^ | | | undeclared label `'a` | help: try using similarly named label: `'b` error[E0426]: use of undeclared label `'a` --> $DIR/label_break_value_invalid.rs:33:29 | LL | let x: u8 = mac3!(break 'a 4); | ^^ undeclared label `'a` error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0426`.