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trait ATC<'a> {
type Type: Sized;
}
trait WithDefault: for<'a> ATC<'a> {
fn with_default<F: for<'a> Fn(<Self as ATC<'a>>::Type)>(f: F);
}
fn call<'b, T: for<'a> ATC<'a>, F: for<'a> Fn(<T as ATC<'a>>::Type)>(
f: F,
x: <T as ATC<'b>>::Type,
) {
f(x);
}
impl<'a> ATC<'a> for () {
type Type = Self;
}
impl WithDefault for () {
fn with_default<F: for<'a> Fn(<Self as ATC<'a>>::Type)>(f: F) {
// Errors with a bogus type mismatch.
//f(());
// Going through another generic function works fine.
call(f, ());
//~^ expected a
}
}
fn main() {
// <()>::with_default(|_| {});
}
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