error: expected identifier, found `,`
  --> $DIR/struct-duplicate-comma.rs:11:14
   |
LL |     let _ = Foo {
   |             --- while parsing this struct
LL |         a: 0,,
   |              ^ expected identifier
   |
help: remove this comma
   |
LL -         a: 0,,
LL +         a: 0,
   |

error: aborting due to 1 previous error