error[E0658]: destructuring assignments are unstable
  --> $DIR/underscore.rs:8:9
   |
LL |         _
   |         ^
   | 
  ::: $DIR/main.rs:5:5
   |
LL |     underscore!();
   |     -------------- in this macro invocation
   |
   = note: see issue #71126 <https://github.com/rust-lang/rust/issues/71126> for more information
   = help: add `#![feature(destructuring_assignment)]` to the crate attributes to enable
   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

error: in expressions, `_` can only be used on the left-hand side of an assignment
  --> $DIR/underscore.rs:8:9
   |
LL |         _
   |         ^ `_` not allowed here
   | 
  ::: $DIR/main.rs:5:5
   |
LL |     underscore!();
   |     -------------- in this macro invocation
   |
   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0658`.