error[E0379]: functions in traits cannot be declared const
  --> $DIR/trait-fn-const.rs:6:5
   |
LL | #[const_trait]
   | -------------- this declares all associated functions implicitly const
LL | trait Trait {
LL |     const fn fun();
   |     ^^^^^-
   |     |
   |     functions in traits cannot be const
   |     help: remove the `const`

error[E0379]: functions in trait impls cannot be declared const
  --> $DIR/trait-fn-const.rs:10:5
   |
LL | impl const Trait for () {
   |      ----- this declares all associated functions implicitly const
LL |     const fn fun() {}
   |     ^^^^^-
   |     |
   |     functions in trait impls cannot be const
   |     help: remove the `const`

error[E0379]: functions in trait impls cannot be declared const
  --> $DIR/trait-fn-const.rs:14:5
   |
LL |     const fn fun() {}
   |     ^^^^^ functions in trait impls cannot be const
   |
help: remove the `const` ...
   |
LL -     const fn fun() {}
LL +     fn fun() {}
   |
help: ... and declare the impl to be const instead
   |
LL | impl const Trait for u32 {
   |      +++++

error[E0379]: functions in traits cannot be declared const
  --> $DIR/trait-fn-const.rs:18:5
   |
LL |     const fn fun();
   |     ^^^^^ functions in traits cannot be const
   |
help: remove the `const` ...
   |
LL -     const fn fun();
LL +     fn fun();
   |
help: ... and declare the trait to be a `#[const_trait]` instead
   |
LL + #[const_trait]
LL | trait NonConst {
   |

warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes
  --> $DIR/trait-fn-const.rs:2:30
   |
LL | #![feature(const_trait_impl, effects)]
   |                              ^^^^^^^
   |
   = note: see issue #102090 <https://github.com/rust-lang/rust/issues/102090> for more information
   = note: `#[warn(incomplete_features)]` on by default

error: aborting due to 4 previous errors; 1 warning emitted

For more information about this error, try `rustc --explain E0379`.