error[E0599]: no method named `len` found for struct `A` in the current scope
  --> $DIR/double-reference-ty-in-self-ty.rs:10:7
   |
LL | struct A;
   | -------- method `len` not found for this struct
...
LL |     fn len(self: &&A) {}
   |        --- the method is available for `&A` here
...
LL |     A.len();
   |       ^^^ method not found in `A`
   |
   = help: items from traits can only be used if the trait is implemented and in scope
   = note: the following trait defines an item `len`, perhaps you need to implement it:
           candidate #1: `ExactSizeIterator`

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0599`.