error[E0308]: mismatched types
  --> $DIR/as-ref.rs:7:29
   |
LL |     opt.map(|arg| takes_ref(arg));
   |                   --------- ^^^ expected `&Foo`, found `Foo`
   |                   |
   |                   arguments to this function are incorrect
   |
note: function defined here
  --> $DIR/as-ref.rs:3:4
   |
LL | fn takes_ref(_: &Foo) {}
   |    ^^^^^^^^^ -------
help: consider using `as_ref` instead
   |
LL |     opt.as_ref().map(|arg| takes_ref(arg));
   |         +++++++++

error[E0308]: mismatched types
  --> $DIR/as-ref.rs:8:39
   |
LL |     opt.and_then(|arg| Some(takes_ref(arg)));
   |                             --------- ^^^ expected `&Foo`, found `Foo`
   |                             |
   |                             arguments to this function are incorrect
   |
note: function defined here
  --> $DIR/as-ref.rs:3:4
   |
LL | fn takes_ref(_: &Foo) {}
   |    ^^^^^^^^^ -------
help: consider using `as_ref` instead
   |
LL |     opt.as_ref().and_then(|arg| Some(takes_ref(arg)));
   |         +++++++++

error[E0308]: mismatched types
  --> $DIR/as-ref.rs:10:29
   |
LL |     opt.map(|arg| takes_ref(arg));
   |                   --------- ^^^ expected `&Foo`, found `Foo`
   |                   |
   |                   arguments to this function are incorrect
   |
note: function defined here
  --> $DIR/as-ref.rs:3:4
   |
LL | fn takes_ref(_: &Foo) {}
   |    ^^^^^^^^^ -------
help: consider using `as_ref` instead
   |
LL |     opt.as_ref().map(|arg| takes_ref(arg));
   |         +++++++++

error[E0308]: mismatched types
  --> $DIR/as-ref.rs:11:37
   |
LL |     opt.and_then(|arg| Ok(takes_ref(arg)));
   |                           --------- ^^^ expected `&Foo`, found `Foo`
   |                           |
   |                           arguments to this function are incorrect
   |
note: function defined here
  --> $DIR/as-ref.rs:3:4
   |
LL | fn takes_ref(_: &Foo) {}
   |    ^^^^^^^^^ -------
help: consider using `as_ref` instead
   |
LL |     opt.as_ref().and_then(|arg| Ok(takes_ref(arg)));
   |         +++++++++

error[E0308]: mismatched types
  --> $DIR/as-ref.rs:13:29
   |
LL |     let y: Option<&usize> = x;
   |            --------------   ^ expected `Option<&usize>`, found `&Option<usize>`
   |            |
   |            expected due to this
   |
   = note:   expected enum `Option<&usize>`
           found reference `&Option<usize>`
help: try using `.as_ref()` to convert `&Option<usize>` to `Option<&usize>`
   |
LL |     let y: Option<&usize> = x.as_ref();
   |                              +++++++++

error[E0308]: mismatched types
  --> $DIR/as-ref.rs:15:37
   |
LL |     let y: Result<&usize, &usize> = x;
   |            ----------------------   ^ expected `Result<&usize, &usize>`, found `&Result<usize, usize>`
   |            |
   |            expected due to this
   |
   = note:   expected enum `Result<&usize, &usize>`
           found reference `&Result<usize, usize>`
help: try using `.as_ref()` to convert `&Result<usize, usize>` to `Result<&usize, &usize>`
   |
LL |     let y: Result<&usize, &usize> = x.as_ref();
   |                                      +++++++++

error[E0308]: mismatched types
  --> $DIR/as-ref.rs:19:36
   |
LL |     let y: Result<&usize, usize> = x;
   |            ---------------------   ^ expected `Result<&usize, usize>`, found `&Result<usize, usize>`
   |            |
   |            expected due to this
   |
   = note:   expected enum `Result<&usize, usize>`
           found reference `&Result<usize, usize>`

error[E0308]: mismatched types
  --> $DIR/as-ref.rs:22:42
   |
LL |     multiple_ref_opt.map(|arg| takes_ref(arg));
   |                                --------- ^^^ expected `&Foo`, found `Foo`
   |                                |
   |                                arguments to this function are incorrect
   |
note: function defined here
  --> $DIR/as-ref.rs:3:4
   |
LL | fn takes_ref(_: &Foo) {}
   |    ^^^^^^^^^ -------
help: consider using `as_ref` instead
   |
LL |     multiple_ref_opt.as_ref().map(|arg| takes_ref(arg));
   |                      +++++++++

error[E0308]: mismatched types
  --> $DIR/as-ref.rs:23:52
   |
LL |     multiple_ref_opt.and_then(|arg| Some(takes_ref(arg)));
   |                                          --------- ^^^ expected `&Foo`, found `Foo`
   |                                          |
   |                                          arguments to this function are incorrect
   |
note: function defined here
  --> $DIR/as-ref.rs:3:4
   |
LL | fn takes_ref(_: &Foo) {}
   |    ^^^^^^^^^ -------
help: consider using `as_ref` instead
   |
LL |     multiple_ref_opt.as_ref().and_then(|arg| Some(takes_ref(arg)));
   |                      +++++++++

error[E0308]: mismatched types
  --> $DIR/as-ref.rs:25:45
   |
LL |     multiple_ref_result.map(|arg| takes_ref(arg));
   |                                   --------- ^^^ expected `&Foo`, found `Foo`
   |                                   |
   |                                   arguments to this function are incorrect
   |
note: function defined here
  --> $DIR/as-ref.rs:3:4
   |
LL | fn takes_ref(_: &Foo) {}
   |    ^^^^^^^^^ -------
help: consider using `as_ref` instead
   |
LL |     multiple_ref_result.as_ref().map(|arg| takes_ref(arg));
   |                         +++++++++

error[E0308]: mismatched types
  --> $DIR/as-ref.rs:26:53
   |
LL |     multiple_ref_result.and_then(|arg| Ok(takes_ref(arg)));
   |                                           --------- ^^^ expected `&Foo`, found `Foo`
   |                                           |
   |                                           arguments to this function are incorrect
   |
note: function defined here
  --> $DIR/as-ref.rs:3:4
   |
LL | fn takes_ref(_: &Foo) {}
   |    ^^^^^^^^^ -------
help: consider using `as_ref` instead
   |
LL |     multiple_ref_result.as_ref().and_then(|arg| Ok(takes_ref(arg)));
   |                         +++++++++

error[E0308]: mismatched types
  --> $DIR/as-ref.rs:28:32
   |
LL |     let _: Result<&usize, _> = &Ok(42);
   |            -----------------   ^^^^^^^ expected `Result<&usize, _>`, found `&Result<{integer}, _>`
   |            |
   |            expected due to this
   |
   = note:   expected enum `Result<&usize, _>`
           found reference `&Result<{integer}, _>`
help: try using `.as_ref()` to convert `&Result<{integer}, _>` to `Result<&usize, _>`
   |
LL -     let _: Result<&usize, _> = &Ok(42);
LL +     let _: Result<&usize, _> = Ok(42).as_ref();
   |

error: aborting due to 12 previous errors

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