error: expected identifier, found `<eof>`
  --> $DIR/mbe-const-trait-bound-theoretical-regression.rs:13:14
   |
LL |     ($ty:ty) => { compile_error!("ty"); };
   |      ------ while parsing argument for this `ty` macro fragment
...
LL | demo! { impl const }
   |              ^^^^^ expected identifier

error: expected identifier, found `<eof>`
  --> $DIR/mbe-const-trait-bound-theoretical-regression.rs:16:13
   |
LL |     ($ty:ty) => { compile_error!("ty"); };
   |      ------ while parsing argument for this `ty` macro fragment
...
LL | demo! { dyn const }
   |             ^^^^^ expected identifier

error[E0658]: const trait impls are experimental
  --> $DIR/mbe-const-trait-bound-theoretical-regression.rs:16:13
   |
LL | demo! { dyn const }
   |             ^^^^^
   |
   = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable

error: aborting due to 3 previous errors

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