No completions for impl blocks on dyn traits with lifetimes

[MaikKlein]

Follow up with #6777 because I noticed that it doesn't work in our internal project. After a quick investigation I noticed that lifetimes on impl blocks cause problems.

For example this code doesn't have any completions with the latest release

trait Foo {
    fn foo_dyn(&self, s: &str);
}

impl dyn Foo + '_ {
    pub fn foo<T: AsRef<str>>(&self, s: T) {
        self.foo_dyn(s.as_ref())
    }
}

impl Foo for u32 {
    fn foo_dyn(&self, s: &str) {
        println!("{} {}", self, s);
    }
}

fn completion(f: &dyn Foo) {
    // No completion
    f.foo("Hello");
}

fn main() {}

No completions if the impl block has a lifetime like this

impl dyn Foo + '_ {
impl<'a> dyn Foo + 'a {
impl dyn Foo + 'static {

[Veykril]

Okay I think I found the problem, in https://github.com/rust-analyzer/rust-analyzer/blob/ba3a5c518a4e20ddacad05d7a8a67704ca2b2a9a/crates/hir_ty/src/lower.rs#L708-L709 the TraitRef::from_type_bound call returns None when we check the lifetime bound as we haven't implemented lifetime generic predicates. Due to that the None gets mapped to a GenericPredicate::Error which then bubbles up to the method resolution stuff which then causes the impl to not match roughly speaking.

[MaikKlein]

Thanks a lot for looking into these issues <3

[Veykril]

I hope it will work for you this time 😄

[MaikKlein]

I hope it will work for you this time

I can confirm that it works on nightly :)