error[E0585]: found a documentation comment that doesn't document anything
  --> $DIR/issue-48636.rs:7:5
   |
LL | struct S {
   |        - while parsing this struct
LL |     x: u8
LL |     /// The ID of the parent core
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: doc comments must come before what they document, if a comment was intended use `//`
help: missing comma here
   |
LL |     x: u8,
   |          +

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0585`.