error[E0573]: expected type, found const parameter `C`
  --> $DIR/struct-with-invalid-const-param.rs:4:23
   |
LL | struct S<const C: u8>(C);
   | ----------------------^--
   | |                     |
   | |                     help: a struct with a similar name exists: `S`
   | similarly named struct `S` defined here

warning: the feature `const_generics` is incomplete and may cause the compiler to crash
  --> $DIR/struct-with-invalid-const-param.rs:1:12
   |
LL | #![feature(const_generics)]
   |            ^^^^^^^^^^^^^^
   |
   = note: `#[warn(incomplete_features)]` on by default

error: aborting due to previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0573`.