rust/tests/ui/generic-const-items/parameter-defaults.rs

#![feature(generic_const_items)]
#![allow(incomplete_features)]

// Check that we emit a *hard* error (not just a lint warning or error for example) for generic
// parameter defaults on free const items since we are not limited by backward compatibility.
#![allow(invalid_type_param_default)] // Should have no effect here.

// FIXME(default_type_parameter_fallback): Consider reallowing them once they work properly.

const NONE<T = ()>: Option<T> = None::<T>; //~ ERROR defaults for type parameters are only allowed

fn main() {
    let _ = NONE;
    //~^ ERROR type annotations needed
}