error[E0308]: mismatched types
  --> $DIR/fully-qualified-type-name2.rs:12:12
   |
LL | fn bar(x: x::Foo) -> y::Foo {
   |                      ------ expected `y::Foo` because of return type
LL |     return x;
   |            ^ expected enum `y::Foo`, found enum `x::Foo`
   |
   = note: enum `x::Foo` and enum `y::Foo` have similar names, but are actually distinct types
note: enum `x::Foo` is defined in module `crate::x` of the current crate
  --> $DIR/fully-qualified-type-name2.rs:4:5
   |
LL |     pub enum Foo { }
   |     ^^^^^^^^^^^^
note: enum `y::Foo` is defined in module `crate::y` of the current crate
  --> $DIR/fully-qualified-type-name2.rs:8:5
   |
LL |     pub enum Foo { }
   |     ^^^^^^^^^^^^

error: aborting due to previous error

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