error: expected one of `)` or `,`, found `(` --> $DIR/test3.rs:5:27 | LL | struct S3(pub($t) ()); | -^ expected one of `)` or `,` | | | help: missing `,` ... LL | define_struct! { foo } | ---------------------- in this macro invocation | = note: this error originates in the macro `define_struct` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0412]: cannot find type `foo` in this scope --> $DIR/test3.rs:11:22 | LL | define_struct! { foo } | ^^^ not found in this scope error[E0412]: cannot find type `foo` in this scope --> $DIR/test3.rs:11:22 | LL | define_struct! { foo } | ^^^ not found in this scope error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0412`.