`Fn` implementation for function pointers to method of `~const` bounded trait are not `const`

[netsutetsu]

I tried this code (playground):

#![feature(const_trait_impl)]

use std::marker::Destruct;

const fn f<T, F: ~const Fn(&T) -> T + ~const Destruct>(_: F) {}

const fn g<T: ~const Clone>() {
    f(<T as Clone>::clone);
}

I got a compile error:

error[E0277]: the trait bound `for<'a> for<'a> fn(&'a T) -> T {<T as Clone>::clone}: ~const Fn<(&'a T,)>` is not satisfied
 --> src\lib.rs:8:7
  |
8 |     f(<T as Clone>::clone);
  |     - ^^^^^^^^^^^^^^^^^^^ expected an `Fn<(&T,)>` closure, found `for<'a> fn(&'a T) -> T {<T as Clone>::clone}`
  |     |
  |     required by a bound introduced by this call
  |
  = help: the trait `for<'a> ~const Fn<(&'a T,)>` is not implemented for fn item `for<'a> fn(&'a T) -> T {<T as Clone>::clone}`
note: the trait `for<'a> Fn<(&'a T,)>` is implemented for `for<'a> fn(&'a T) -> T {<T as Clone>::clone}`, but that implementation is not `const`
 --> src\lib.rs:8:7
  |
8 |     f(<T as Clone>::clone);
  |       ^^^^^^^^^^^^^^^^^^^
note: required by a bound in `f`
 --> src\lib.rs:5:18
  |
5 | const fn f<T, F: ~const Fn(&T) -> T + ~const Destruct>(_: F) {}
  |                  ^^^^^^^^^^^^^^^^^^ required by this bound in `f`

Meta

rustc --version --verbose:

rustc 1.67.0-nightly (42325c525 2022-11-11)
binary: rustc
commit-hash: 42325c525b9d3885847a3f803abe53c562d289da
commit-date: 2022-11-11
host: x86_64-pc-windows-msvc
release: 1.67.0-nightly
LLVM version: 15.0.4

[netsutetsu]

@rustbot label: +A-const-fn +F-const_trait_impl

[compiler-errors]

I think this is because Default is not marked as a #[const_trait].

[netsutetsu]

I think this is because Default is not marked as a #[const_trait].

I originally encountered this with Clone, I'll fix.

[netsutetsu]

@compiler-errors I fixed the example.