error[E0616]: field `bits` of struct `Flags1` is private
  --> $DIR/private_field.rs:12:41
   |
12 |     let flag1 = example::Flags1::FLAG_A.bits;
   |                                         ^^^^ private field
   |
help: a method `bits` also exists, call it with parentheses
   |
12 |     let flag1 = example::Flags1::FLAG_A.bits();
   |                                             ^^