error: expected one of `)` or `,`, found `(` --> $DIR/test2.rs:5:26 | 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/test2.rs:11:23 | LL | define_struct! { (foo) } | ^^^ not found in this scope error[E0412]: cannot find type `foo` in this scope --> $DIR/test2.rs:11:23 | LL | define_struct! { (foo) } | ^^^ not found in this scope | = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0412`.