error[E0109]: type arguments are not allowed on type parameter `Irrelevant` --> $DIR/issue-97343.rs:4:23 | LL | #[derive(Debug)] | ----- | | | not allowed on type parameter `Irrelevant` | in this derive macro expansion LL | pub struct Irrelevant { | ^^^^^^^^^^ type argument not allowed | note: type parameter `Irrelevant` defined here --> $DIR/issue-97343.rs:4:23 | LL | pub struct Irrelevant { | ^^^^^^^^^^ = note: this error originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info) error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0109`.