phlite: method selection on subtype of opaque

[lcnr]

https://crater-reports.s3.amazonaws.com/pr-133502-11/try%2328f13ad7c79d80decb5a3d54595a8b4105f397a3/gh/tomchaplin.phlite/log.txt

minimized

trait Trait {
    fn method(self);
}
impl<T> Trait for T {
    fn method(self) {}
}

fn recur(b: bool) -> impl Trait {
    if b {
        let local = recur(false);
        local.method();
    }
}
fn main() {}