error[E0412]: cannot find type `N` in this scope
  --> $DIR/diagnostics.rs:7:16
   |
LL | struct A<const N: u8>;
   | ---------------------- similarly named struct `A` defined here
LL | trait Foo {}
LL | impl Foo for A<N> {}
   |                ^ help: a struct with a similar name exists: `A`

error[E0412]: cannot find type `T` in this scope
  --> $DIR/diagnostics.rs:16:32
   |
LL | struct A<const N: u8>;
   | ---------------------- similarly named struct `A` defined here
...
LL | impl<const N: u8> Foo for C<N, T> {}
   |                                ^ help: a struct with a similar name exists: `A`

error[E0747]: unresolved item provided when a constant was expected
  --> $DIR/diagnostics.rs:7:16
   |
LL | impl Foo for A<N> {}
   |                ^
   |
help: if this generic argument was intended as a const parameter, surround it with braces
   |
LL | impl Foo for A<{ N }> {}
   |                ^   ^

error[E0747]: type provided when a constant was expected
  --> $DIR/diagnostics.rs:12:19
   |
LL | impl<N> Foo for B<N> {}
   |      -            ^
   |      |
   |      help: consider changing this type paramater to a `const`-generic: `const N: u8`

error[E0747]: unresolved item provided when a constant was expected
  --> $DIR/diagnostics.rs:16:32
   |
LL | impl<const N: u8> Foo for C<N, T> {}
   |                                ^
   |
help: if this generic argument was intended as a const parameter, surround it with braces
   |
LL | impl<const N: u8> Foo for C<N, { T }> {}
   |                                ^   ^

error: aborting due to 5 previous errors

Some errors have detailed explanations: E0412, E0747.
For more information about an error, try `rustc --explain E0412`.