rust/tests/ui/higher-ranked/trait-bounds/hrtb-higher-ranker-supertraits.rs

// Test a trait (`Bar`) with a higher-ranked supertrait.

trait Foo<'tcx>
{
    fn foo(&'tcx self) -> &'tcx isize;
}

trait Bar<'ccx>
    : for<'tcx> Foo<'tcx>
{
    fn bar(&'ccx self) -> &'ccx isize;
}

fn want_foo_for_some_tcx<'x,F>(f: &'x F)
    where F : Foo<'x>
{
    want_foo_for_some_tcx(f);
    want_foo_for_any_tcx(f); //~ ERROR not satisfied
}

fn want_foo_for_any_tcx<F>(f: &F) //~ WARN cannot return without recursing
    where F : for<'tcx> Foo<'tcx>
{
    want_foo_for_some_tcx(f);
    want_foo_for_any_tcx(f);
}

fn want_bar_for_some_ccx<'x,B>(b: &B)
    where B : Bar<'x>
{
    want_foo_for_some_tcx(b);
    want_foo_for_any_tcx(b);

    want_bar_for_some_ccx(b);
    want_bar_for_any_ccx(b); //~ ERROR not satisfied
}

fn want_bar_for_any_ccx<B>(b: &B) //~ WARN cannot return without recursing
    where B : for<'ccx> Bar<'ccx>
{
    want_foo_for_some_tcx(b);
    want_foo_for_any_tcx(b);

    want_bar_for_some_ccx(b);
    want_bar_for_any_ccx(b);
}

fn main() {}