error[E0106]: missing lifetime specifier
  --> $DIR/unusual-rib-combinations.rs:24:15
   |
LL | fn d<const C: S>() {}
   |               ^ expected named lifetime parameter
   |
help: consider introducing a named lifetime parameter
   |
LL | fn d<'a, const C: S<'a>>() {}
   |      +++           ++++

error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
  --> $DIR/unusual-rib-combinations.rs:7:16
   |
LL | fn a() -> [u8; foo::()] {
   |                ^^^^^^^ only `Fn` traits may use parentheses

error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
  --> $DIR/unusual-rib-combinations.rs:14:15
   |
LL | fn b<const C: u8()>() {}
   |               ^^^^ only `Fn` traits may use parentheses

error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
  --> $DIR/unusual-rib-combinations.rs:18:10
   |
LL | fn c<T = u8()>() {}
   |          ^^^^ only `Fn` traits may use parentheses

error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
  --> $DIR/unusual-rib-combinations.rs:18:6
   |
LL | fn c<T = u8()>() {}
   |      ^^^^^^^^
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #36887 <https://github.com/rust-lang/rust/issues/36887>
   = note: `#[deny(invalid_type_param_default)]` on by default

error[E0308]: mismatched types
  --> $DIR/unusual-rib-combinations.rs:7:16
   |
LL | fn a() -> [u8; foo::()] {
   |                ^^^^^^^ expected `usize`, found fn item
   |
   = note: expected type `usize`
           found fn item `fn() {foo}`

error: `S<'_>` is forbidden as the type of a const generic parameter
  --> $DIR/unusual-rib-combinations.rs:24:15
   |
LL | fn d<const C: S>() {}
   |               ^
   |
   = note: the only supported types are integers, `bool` and `char`
   = help: more complex types are supported with `#![feature(adt_const_params)]`

error: aborting due to 7 previous errors

Some errors have detailed explanations: E0106, E0214, E0308.
For more information about an error, try `rustc --explain E0106`.