error[E0782]: expected a type, found a trait
  --> $DIR/dyn-trait-sugg-2021.rs:10:5
   |
LL |     Foo::hi(123);
   |     ^^^
   |
help: you can add the `dyn` keyword if you want a trait object
   |
LL |     <dyn Foo>::hi(123);
   |     ++++    +

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0782`.