error[E0609]: no field `c` on type `&Foo`
  --> $DIR/issue-30580.rs:12:11
   |
LL |         b.c;
   |           ^ unknown field
   |
help: a field with a similar name exists
   |
LL |         b.a;
   |           ~

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0609`.