error: You matched a field with a wildcard pattern. Consider using `..` instead
  --> $DIR/unneeded_field_pattern.rs:17:15
   |
17 |         Foo { a: _, b: 0, .. } => {}
   |               ^^^^
   |
   = note: `-D unneeded-field-pattern` implied by `-D warnings`
   = help: Try with `Foo { b: 0, .. }`

error: All the struct fields are matched to a wildcard pattern, consider using `..`.
  --> $DIR/unneeded_field_pattern.rs:19:9
   |
19 |         Foo { a: _, b: _, c: _ } => {}
   |         ^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: Try with `Foo { .. }` instead

error: aborting due to 2 previous errors