error: expected identifier, found `,`
  --> $DIR/issue-10392.rs:6:13
   |
LL |     let A { , } = a(); //~ ERROR expected ident
   |             ^ expected identifier

error[E0027]: pattern does not mention field `foo`
  --> $DIR/issue-10392.rs:6:9
   |
LL |     let A { , } = a(); //~ ERROR expected ident
   |         ^^^^^^^ missing field `foo`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0027`.