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:8:12 | LL | #![feature(const_cmp)] | ^^^^^^^^^ error: ~const can only be applied to `#[const_trait]` traits --> $DIR/fn_trait_refs.rs:15:15 | LL | T: ~const Fn<()> + ~const Destruct, | ^^^^^^ error: ~const can only be applied to `#[const_trait]` traits --> $DIR/fn_trait_refs.rs:15:15 | LL | T: ~const Fn<()> + ~const Destruct, | ^^^^^^ error: ~const can only be applied to `#[const_trait]` traits --> $DIR/fn_trait_refs.rs:22:15 | LL | T: ~const FnMut<()> + ~const Destruct, | ^^^^^^^^^ error: ~const can only be applied to `#[const_trait]` traits --> $DIR/fn_trait_refs.rs:22:15 | LL | T: ~const FnMut<()> + ~const Destruct, | ^^^^^^^^^ error: ~const can only be applied to `#[const_trait]` traits --> $DIR/fn_trait_refs.rs:29:15 | LL | T: ~const FnOnce<()>, | ^^^^^^^^^^ error: ~const can only be applied to `#[const_trait]` traits --> $DIR/fn_trait_refs.rs:29:15 | LL | T: ~const FnOnce<()>, | ^^^^^^^^^^ error: ~const can only be applied to `#[const_trait]` traits --> $DIR/fn_trait_refs.rs:36:15 | LL | T: ~const Fn<()> + ~const Destruct, | ^^^^^^ error: ~const can only be applied to `#[const_trait]` traits --> $DIR/fn_trait_refs.rs:36:15 | LL | T: ~const Fn<()> + ~const Destruct, | ^^^^^^ error: ~const can only be applied to `#[const_trait]` traits --> $DIR/fn_trait_refs.rs:50:15 | LL | T: ~const FnMut<()> + ~const Destruct, | ^^^^^^^^^ error: ~const can only be applied to `#[const_trait]` traits --> $DIR/fn_trait_refs.rs:50:15 | LL | T: ~const FnMut<()> + ~const Destruct, | ^^^^^^^^^ error: aborting due to 12 previous errors For more information about this error, try `rustc --explain E0635`.