pub trait A where Self: 'static {
  fn foo<'a>(self) -> Foo<'a>;
}

pub enum Foo<'a> {
  Bar(B<'a>),
  Baz(C<'a>),
}

pub struct B<'a> {
  b: &'a str,
}

pub struct C<'a> {
  c: &'a str,
}

impl A for B<'static> {
  fn foo<'a>(self) -> Foo<'a> {
    Foo::Baz(C {
      c: self.b,
    })
  }
}

fn main() {}