error[E0631]: type mismatch in closure arguments
  --> $DIR/closure-arg-type-mismatch.rs:3:14
   |
LL |     a.iter().map(|_: (u32, u32)| 45);
   |              ^^^ --------------- found signature defined here
   |              |
   |              expected due to this
   |
   = note: expected closure signature `fn(&(_, _)) -> _`
              found closure signature `fn((_, _)) -> _`
note: required by a bound in `map`
  --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
help: consider adjusting the signature so it borrows its argument
   |
LL |     a.iter().map(|_: &(u32, u32)| 45);
   |                      +

error[E0631]: type mismatch in closure arguments
  --> $DIR/closure-arg-type-mismatch.rs:4:14
   |
LL |     a.iter().map(|_: &(u16, u16)| 45);
   |              ^^^ ---------------- found signature defined here
   |              |
   |              expected due to this
   |
   = note: expected closure signature `fn(&(u32, u32)) -> _`
              found closure signature `fn(&(u16, u16)) -> _`
note: required by a bound in `map`
  --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL

error[E0631]: type mismatch in closure arguments
  --> $DIR/closure-arg-type-mismatch.rs:5:14
   |
LL |     a.iter().map(|_: (u16, u16)| 45);
   |              ^^^ --------------- found signature defined here
   |              |
   |              expected due to this
   |
   = note: expected closure signature `fn(&(u32, u32)) -> _`
              found closure signature `fn((u16, u16)) -> _`
note: required by a bound in `map`
  --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL

error[E0521]: borrowed data escapes outside of function
  --> $DIR/closure-arg-type-mismatch.rs:10:5
   |
LL | fn _test<'a>(f: fn(*mut &'a u32)) {
   |          --  - `f` is a reference that is only valid in the function body
   |          |
   |          lifetime `'a` defined here
LL |     baz(f);
   |     ^^^^^^
   |     |
   |     `f` escapes the function body here
   |     argument requires that `'a` must outlive `'static`
   |
   = note: requirement occurs because of a mutable pointer to `&u32`
   = note: mutable pointers are invariant over their type parameter
   = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
note: due to current limitations in the borrow checker, this implies a `'static` lifetime
  --> $DIR/closure-arg-type-mismatch.rs:8:11
   |
LL | fn baz<F: Fn(*mut &u32)>(_: F) {}
   |           ^^^^^^^^^^^^^

error: implementation of `Fn` is not general enough
  --> $DIR/closure-arg-type-mismatch.rs:10:5
   |
LL |     baz(f);
   |     ^^^^^^ implementation of `Fn` is not general enough
   |
   = note: `fn(*mut &'2 u32)` must implement `Fn<(*mut &'1 u32,)>`, for any lifetime `'1`...
   = note: ...but it actually implements `Fn<(*mut &'2 u32,)>`, for some specific lifetime `'2`

error: implementation of `FnOnce` is not general enough
  --> $DIR/closure-arg-type-mismatch.rs:10:5
   |
LL |     baz(f);
   |     ^^^^^^ implementation of `FnOnce` is not general enough
   |
   = note: `fn(*mut &'2 u32)` must implement `FnOnce<(*mut &'1 u32,)>`, for any lifetime `'1`...
   = note: ...but it actually implements `FnOnce<(*mut &'2 u32,)>`, for some specific lifetime `'2`

error: aborting due to 6 previous errors

Some errors have detailed explanations: E0521, E0631.
For more information about an error, try `rustc --explain E0521`.