error: expected identifier, found keyword `let` --> $DIR/removed-syntax-field-let.rs:2:5 | LL | let foo: (), | ^^^- | | | expected identifier, found keyword | help: remove this `let` keyword | = note: the `let` keyword is not allowed in `struct` fields = note: see <https://doc.rust-lang.org/book/ch05-01-defining-structs.html> for more information error: aborting due to previous error