error[E0425]: cannot find value `_5` in this scope
 --> tests/compile_fail/self_references/unknown_reference.rs:6:22
  |
6 |     #[attr(a = #self.5)]
  |                      ^ help: a local variable with a similar name exists: `_0`

error[E0425]: cannot find value `unknown` in this scope
 --> tests/compile_fail/self_references/unknown_reference.rs:9:22
  |
9 |     #[attr(a = #self.unknown)]
  |                      ^^^^^^^ not found in this scope