error: expected one of `(`, `async`, `const`, `default`, `extern`, `fn`, `safe`, `unsafe`, or `use`, found keyword `pub`
  --> $DIR/duplicate-visibility.rs:4:9
   |
LL | extern "C" {
   |            - while parsing this item list starting here
LL |     pub pub fn foo();
   |         ^^^
   |         |
   |         expected one of 9 possible tokens
   |         help: there is already a visibility modifier, remove one
...
LL | }
   | - the item list ends here
   |
note: explicit visibility first seen here
  --> $DIR/duplicate-visibility.rs:4:5
   |
LL |     pub pub fn foo();
   |     ^^^

error: aborting due to 1 previous error