error[E0423]: expected function, tuple struct or tuple variant, found struct `X`
  --> $DIR/issue-64792-bad-unicode-ctor.rs:3:14
   |
LL | struct X {}
   | ----------- `X` defined here
LL |
LL | const Y: X = X("ö");
   |              ^^^^^^ help: use struct literal syntax instead: `X {}`

error: aborting due to 1 previous error

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