warning: irrefutable while-let pattern
  --> $DIR/while-let.rs:7:13
   |
LL |               while let $p = $e $b
   |               ^^^^^^^^^^^^^^^^^^^^
...
LL | /     foo!(_a, 1, {
LL | |         println!("irrefutable pattern");
LL | |     });
   | |_______- in this macro invocation
   |
   = note: `#[warn(irrefutable_let_patterns)]` on by default
   = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

warning: irrefutable while-let pattern
  --> $DIR/while-let.rs:7:13
   |
LL |               while let $p = $e $b
   |               ^^^^^^^^^^^^^^^^^^^^
...
LL | /     bar!(_a, 1, {
LL | |         println!("irrefutable pattern");
LL | |     });
   | |_______- in this macro invocation
   |
   = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

warning: irrefutable while-let pattern
  --> $DIR/while-let.rs:27:5
   |
LL | /     while let _a = 1 {
LL | |         println!("irrefutable pattern");
LL | |         break;
LL | |     }
   | |_____^

warning: 3 warnings emitted