error[E0659]: `Foo` is ambiguous
  --> $DIR/rfc-1560-warning-cycle.rs:19:17
   |
LL |         fn f(_: Foo) {} //~ ERROR `Foo` is ambiguous
   |                 ^^^
   |
note: `Foo` could refer to the name imported here
  --> $DIR/rfc-1560-warning-cycle.rs:17:13
   |
LL |         use *;
   |             ^
note: `Foo` could also refer to the name imported here
  --> $DIR/rfc-1560-warning-cycle.rs:18:13
   |
LL |         use bar::*;
   |             ^^^^^^
   = note: consider adding an explicit import of `Foo` to disambiguate

error: aborting due to previous error

For more information about this error, try `rustc --explain E0659`.