error[E0308]: mismatched types
  --> $DIR/suggest-full-enum-variant-for-local-module.rs:9:28
   |
LL |     let _: option::O<()> = ();
   |            -------------   ^^ expected `O<()>`, found `()`
   |            |
   |            expected due to this
   |
   = note:   expected enum `O<()>`
           found unit type `()`
help: try wrapping the expression in `option::O::Some`
   |
LL |     let _: option::O<()> = option::O::Some(());
   |                            ++++++++++++++++  +

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0308`.