error[E0407]: method `unimplemented` is not a member of trait `std::ops::Add`
  --> $DIR/post-analysis-user-facing-param-env.rs:11:5
   |
LL | /     fn unimplemented(self, _: &Foo) -> Self::Output {
LL | |
LL | |
LL | |         loop {}
LL | |     }
   | |_____^ not a member of trait `std::ops::Add`

warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes
  --> $DIR/post-analysis-user-facing-param-env.rs:2:12
   |
LL | #![feature(generic_const_exprs)]
   |            ^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #76560 <https://github.com/rust-lang/rust/issues/76560> for more information
   = note: `#[warn(incomplete_features)]` on by default

error[E0207]: the const parameter `NUM` is not constrained by the impl trait, self type, or predicates
  --> $DIR/post-analysis-user-facing-param-env.rs:6:10
   |
LL | impl<'a, const NUM: usize> std::ops::Add<&'a Foo> for Foo
   |          ^^^^^^^^^^^^^^^^ unconstrained const parameter
   |
   = note: expressions using a const parameter must map each value to a distinct output value
   = note: proving the result of expressions other than the parameter are unique is not supported

error[E0284]: type annotations needed
  --> $DIR/post-analysis-user-facing-param-env.rs:11:40
   |
LL |     fn unimplemented(self, _: &Foo) -> Self::Output {
   |                                        ^^^^^^^^^^^^ cannot infer the value of const parameter `NUM`
   |
note: required for `Foo` to implement `Add<&'a Foo>`
  --> $DIR/post-analysis-user-facing-param-env.rs:6:28
   |
LL | impl<'a, const NUM: usize> std::ops::Add<&'a Foo> for Foo
   |          ----------------  ^^^^^^^^^^^^^^^^^^^^^^     ^^^
   |          |
   |          unsatisfied trait bound introduced here

error: aborting due to 3 previous errors; 1 warning emitted

Some errors have detailed explanations: E0207, E0284, E0407.
For more information about an error, try `rustc --explain E0207`.