error: more than 0 bools in a struct
  --> $DIR/test.rs:3:1
   |
LL | / struct S {
LL | |     a: bool,
LL | | }
   | |_^
   |
   = note: `-D clippy::struct-excessive-bools` implied by `-D warnings`
   = help: consider using a state machine or refactoring bools into two-variant enums

error: aborting due to previous error