Smarter derive(Default) for PhantomData

[ark0f]

use std::marker::PhantomData;

struct TypeWithoutDefault;

#[derive(Default)]
struct NewType<T>(PhantomData<T>);

fn main() {
    let _ = NewType::<TypeWithoutDefault>::default();
    // ^ E0599
    // no function or associated item named `default` found 
    // for type `NewType<TypeWithoutDefault>` in the current scope
}

But if we implement Default without derive:

impl<T> Default for NewType<T> {
    fn default() -> Self {
        Self(PhantomData)
    }
}

Then code compiles successfully.

Can derive(Default) be smarter for cases like this?

[jonas-schievink]

Duplicate of #26925