error[E0282]: type annotations needed
  --> $DIR/cannot-infer-const-args.rs:6:5
   |
LL |     foo();
   |     ^^^ cannot infer the value of the const parameter `X` declared on the function `foo`
   |
help: consider specifying the generic argument
   |
LL |     foo::<X>();
   |        +++++

error: aborting due to previous error

For more information about this error, try `rustc --explain E0282`.