error[E0601]: `main` function not found in crate `issue_65466`
  --> $DIR/issue-65466.rs:1:1
   |
LL | / #![deny(indirect_structural_match)]
LL | |
LL | | #[derive(PartialEq, Eq)]
LL | | enum O<T> {
...  |
LL | |     }
LL | | }
   | |_^ consider adding a `main` function to `$DIR/issue-65466.rs`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0601`.