src/test/ui/rfc-2565-param-attrs/param-attrs-feature-gate.rs

// gate-test-param_attrs

fn foo(
    /// Foo
    //~^ ERROR documentation comments cannot be applied to function parameters
    //~| NOTE doc comments are not allowed here
    //~| ERROR attributes on function parameters are unstable
    //~| NOTE https://github.com/rust-lang/rust/issues/60406
    #[allow(C)] a: u8
    //~^ ERROR attributes on function parameters are unstable
    //~| NOTE https://github.com/rust-lang/rust/issues/60406
) {}

fn main() {}