error[E0423]: cannot initialize a tuple struct which contains private fields
  --> $DIR/issue-75906.rs:11:13
   |
LL |     let y = Bar(12);
   |             ^^^
   |
note: constructor is not visible here due to private fields
  --> $DIR/issue-75906.rs:4:20
   |
LL |     pub struct Bar(u8);
   |                    ^^ private field

error: aborting due to previous error

For more information about this error, try `rustc --explain E0423`.