error[E0635]: unknown feature `const_fn_trait_ref_impls`
  --> $DIR/fn_trait_refs.rs:3:12
   |
LL | #![feature(const_fn_trait_ref_impls)]
   |            ^^^^^^^^^^^^^^^^^^^^^^^^

error[E0635]: unknown feature `const_cmp`
  --> $DIR/fn_trait_refs.rs:7:12
   |
LL | #![feature(const_cmp)]
   |            ^^^^^^^^^

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:14:8
   |
LL |     T: ~const Fn<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `Fn`
   |
note: `Fn` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:14:8
   |
LL |     T: ~const Fn<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `Fn`
   |
note: `Fn` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:14:8
   |
LL |     T: ~const Fn<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `Fn`
   |
note: `Fn` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:21:8
   |
LL |     T: ~const FnMut<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `FnMut`
   |
note: `FnMut` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:21:8
   |
LL |     T: ~const FnMut<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `FnMut`
   |
note: `FnMut` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:21:8
   |
LL |     T: ~const FnMut<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `FnMut`
   |
note: `FnMut` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:28:8
   |
LL |     T: ~const FnOnce<()>,
   |        ^^^^^^ can't be applied to `FnOnce`
   |
note: `FnOnce` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:28:8
   |
LL |     T: ~const FnOnce<()>,
   |        ^^^^^^ can't be applied to `FnOnce`
   |
note: `FnOnce` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:28:8
   |
LL |     T: ~const FnOnce<()>,
   |        ^^^^^^ can't be applied to `FnOnce`
   |
note: `FnOnce` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:35:8
   |
LL |     T: ~const Fn<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `Fn`
   |
note: `Fn` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:35:8
   |
LL |     T: ~const Fn<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `Fn`
   |
note: `Fn` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:35:8
   |
LL |     T: ~const Fn<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `Fn`
   |
note: `Fn` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:49:8
   |
LL |     T: ~const FnMut<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `FnMut`
   |
note: `FnMut` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:49:8
   |
LL |     T: ~const FnMut<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `FnMut`
   |
note: `FnMut` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/fn_trait_refs.rs:49:8
   |
LL |     T: ~const FnMut<()> + ~const Destruct,
   |        ^^^^^^ can't be applied to `FnMut`
   |
note: `FnMut` can't be used with `~const` because it isn't annotated with `#[const_trait]`
  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error[E0277]: the trait bound `fn() -> i32 {one}: const Destruct` is not satisfied
  --> $DIR/fn_trait_refs.rs:70:32
   |
LL |         let test_one = test_fn(one);
   |                        ------- ^^^
   |                        |
   |                        required by a bound introduced by this call
   |
note: required by a bound in `test_fn`
  --> $DIR/fn_trait_refs.rs:35:24
   |
LL | const fn test_fn<T>(mut f: T) -> (T::Output, T::Output, T::Output)
   |          ------- required by a bound in this function
LL | where
LL |     T: ~const Fn<()> + ~const Destruct,
   |                        ^^^^^^ required by this bound in `test_fn`

error[E0277]: the trait bound `fn() -> i32 {two}: const Destruct` is not satisfied
  --> $DIR/fn_trait_refs.rs:73:36
   |
LL |         let test_two = test_fn_mut(two);
   |                        ----------- ^^^
   |                        |
   |                        required by a bound introduced by this call
   |
note: required by a bound in `test_fn_mut`
  --> $DIR/fn_trait_refs.rs:49:27
   |
LL | const fn test_fn_mut<T>(mut f: T) -> (T::Output, T::Output)
   |          ----------- required by a bound in this function
LL | where
LL |     T: ~const FnMut<()> + ~const Destruct,
   |                           ^^^^^^ required by this bound in `test_fn_mut`

error[E0277]: the trait bound `&T: ~const Destruct` is not satisfied
  --> $DIR/fn_trait_refs.rs:39:19
   |
LL |         tester_fn(&f),
   |         --------- ^^
   |         |
   |         required by a bound introduced by this call
   |
note: required by a bound in `tester_fn`
  --> $DIR/fn_trait_refs.rs:14:24
   |
LL | const fn tester_fn<T>(f: T) -> T::Output
   |          --------- required by a bound in this function
LL | where
LL |     T: ~const Fn<()> + ~const Destruct,
   |                        ^^^^^^ required by this bound in `tester_fn`

error[E0277]: the trait bound `&T: ~const Destruct` is not satisfied
  --> $DIR/fn_trait_refs.rs:41:23
   |
LL |         tester_fn_mut(&f),
   |         ------------- ^^
   |         |
   |         required by a bound introduced by this call
   |
note: required by a bound in `tester_fn_mut`
  --> $DIR/fn_trait_refs.rs:21:27
   |
LL | const fn tester_fn_mut<T>(mut f: T) -> T::Output
   |          ------------- required by a bound in this function
LL | where
LL |     T: ~const FnMut<()> + ~const Destruct,
   |                           ^^^^^^ required by this bound in `tester_fn_mut`

error[E0277]: the trait bound `&mut T: ~const Destruct` is not satisfied
  --> $DIR/fn_trait_refs.rs:53:23
   |
LL |         tester_fn_mut(&mut f),
   |         ------------- ^^^^^^
   |         |
   |         required by a bound introduced by this call
   |
note: required by a bound in `tester_fn_mut`
  --> $DIR/fn_trait_refs.rs:21:27
   |
LL | const fn tester_fn_mut<T>(mut f: T) -> T::Output
   |          ------------- required by a bound in this function
LL | where
LL |     T: ~const FnMut<()> + ~const Destruct,
   |                           ^^^^^^ required by this bound in `tester_fn_mut`

error[E0015]: cannot call non-const closure in constant functions
  --> $DIR/fn_trait_refs.rs:16:5
   |
LL |     f()
   |     ^^^
   |
   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants

error[E0015]: cannot call non-const closure in constant functions
  --> $DIR/fn_trait_refs.rs:23:5
   |
LL |     f()
   |     ^^^
   |
   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants

error[E0015]: cannot call non-const closure in constant functions
  --> $DIR/fn_trait_refs.rs:30:5
   |
LL |     f()
   |     ^^^
   |
   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants

error: aborting due to 25 previous errors

Some errors have detailed explanations: E0015, E0277, E0635.
For more information about an error, try `rustc --explain E0015`.