error[E0106]: missing lifetime specifier
  --> $DIR/opaque-used-in-extraneous-argument.rs:5:39
   |
LL | fn frob() -> impl Fn<P, Output = T> + '_ {}
   |                                       ^^ expected named lifetime parameter
   |
   = help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from
help: consider using the `'static` lifetime, but this is uncommon unless you're returning a borrowed value from a `const` or a `static`, or if you will only have owned values
   |
LL | fn frob() -> impl Fn<P, Output = T> + 'static {}
   |                                       ~~~~~~~

error[E0412]: cannot find type `P` in this scope
  --> $DIR/opaque-used-in-extraneous-argument.rs:5:22
   |
LL | fn frob() -> impl Fn<P, Output = T> + '_ {}
   |                      ^ not found in this scope
   |
help: you might be missing a type parameter
   |
LL | fn frob<P>() -> impl Fn<P, Output = T> + '_ {}
   |        +++

error[E0412]: cannot find type `T` in this scope
  --> $DIR/opaque-used-in-extraneous-argument.rs:5:34
   |
LL | fn frob() -> impl Fn<P, Output = T> + '_ {}
   |                                  ^ not found in this scope
   |
help: you might be missing a type parameter
   |
LL | fn frob<T>() -> impl Fn<P, Output = T> + '_ {}
   |        +++

error[E0658]: the precise format of `Fn`-family traits' type parameters is subject to change
  --> $DIR/opaque-used-in-extraneous-argument.rs:5:19
   |
LL | fn frob() -> impl Fn<P, Output = T> + '_ {}
   |                   ^^^^^^^^^^^^^^^^^ help: use parenthetical notation instead: `Fn(P) -> T`
   |
   = note: see issue #29625 <https://github.com/rust-lang/rust/issues/29625> for more information
   = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date

error[E0658]: the precise format of `Fn`-family traits' type parameters is subject to change
  --> $DIR/opaque-used-in-extraneous-argument.rs:5:19
   |
LL | fn frob() -> impl Fn<P, Output = T> + '_ {}
   |                   ^^^^^^^^^^^^^^^^^ help: use parenthetical notation instead: `Fn(P) -> T`
   |
   = note: see issue #29625 <https://github.com/rust-lang/rust/issues/29625> for more information
   = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error[E0061]: this function takes 0 arguments but 1 argument was supplied
  --> $DIR/opaque-used-in-extraneous-argument.rs:17:20
   |
LL |     let old_path = frob("hello");
   |                    ^^^^ ------- unexpected argument of type `&'static str`
   |
note: function defined here
  --> $DIR/opaque-used-in-extraneous-argument.rs:5:4
   |
LL | fn frob() -> impl Fn<P, Output = T> + '_ {}
   |    ^^^^
help: remove the extra argument
   |
LL -     let old_path = frob("hello");
LL +     let old_path = frob();
   |

error[E0061]: this function takes 0 arguments but 1 argument was supplied
  --> $DIR/opaque-used-in-extraneous-argument.rs:20:5
   |
LL |     open_parent(&old_path)
   |     ^^^^^^^^^^^ --------- unexpected argument of type `&impl FnOnce<{type error}, Output = {type error}> + Fn<{type error}> + 'static`
   |
note: function defined here
  --> $DIR/opaque-used-in-extraneous-argument.rs:12:4
   |
LL | fn open_parent<'path>() {
   |    ^^^^^^^^^^^
help: remove the extra argument
   |
LL -     open_parent(&old_path)
LL +     open_parent()
   |

error: aborting due to 7 previous errors

Some errors have detailed explanations: E0061, E0106, E0412, E0658.
For more information about an error, try `rustc --explain E0061`.