Invalid suggestion to use a vertical bar in `let a, b = x;`

[goffrie]

Introduced in #57008, the following program

fn main() {
    let a, b = x;
}

yields the following message:

error: unexpected `,` in pattern
 --> src/main.rs:2:10
  |
2 |     let a, b = x;
  |          ^
help: try adding parentheses to match on a tuple..
  |
2 |     let (a, b) = x;
  |         ^^^^^^
help: ..or a vertical bar to match on multiple alternatives
  |
2 |     let a | b = x;
  |         ^^^^^

However, the suggestion let a | b = x; is nonsensical.

[petrochenkov]

let a | b is supposed to work eventually (#48215, #54883), but it's not yet implemented.

[goffrie]

I see. However, in this case, a | b would still not be a legal pattern.

[compiler-errors]

This was resolved.