warning: trailing semicolon in macro used in expression position
  --> $DIR/warn-semicolon-in-expressions-from-macros.rs:6:13
   |
LL |         true;
   |             ^
...
LL |         _ => foo!()
   |              ------ in this macro invocation
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
   = note: `#[warn(semicolon_in_expressions_from_macros)]` on by default
   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)

warning: 1 warning emitted

Future incompatibility report: Future breakage diagnostic:
warning: trailing semicolon in macro used in expression position
  --> $DIR/warn-semicolon-in-expressions-from-macros.rs:6:13
   |
LL |         true;
   |             ^
...
LL |         _ => foo!()
   |              ------ in this macro invocation
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
   = note: `#[warn(semicolon_in_expressions_from_macros)]` on by default
   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)