error[E0521]: borrowed data escapes outside of associated function
  --> $DIR/issue-17758.rs:7:9
   |
LL | trait Foo<'a> {
   |           -- lifetime `'a` defined here
LL |     fn foo(&'a self);
LL |     fn bar(&self) {
   |            -----
   |            |
   |            `self` is a reference that is only valid in the associated function body
   |            let's call the lifetime of this reference `'1`
LL |         self.foo();
   |         ^^^^^^^^^^
   |         |
   |         `self` escapes the associated function body here
   |         argument requires that `'1` must outlive `'a`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0521`.