warning: `#[derive]` does nothing on macro invocations
  --> $DIR/issue-49934.rs:29:5
   |
LL |     #[derive(Debug)]
   |     ^^^^^^^^^^^^^^^^
   |
   = note: this may become a hard error in a future release

warning: unused attribute
  --> $DIR/issue-49934.rs:17:9
   |
LL |         #[derive(Debug)] //~ WARN unused attribute
   |         ^^^^^^^^^^^^^^^^
   |
note: lint level defined here
  --> $DIR/issue-49934.rs:13:9
   |
LL | #![warn(unused_attributes)] //~ NOTE lint level defined here
   |         ^^^^^^^^^^^^^^^^^

warning: unused attribute
  --> $DIR/issue-49934.rs:35:5
   |
LL |     #[derive(Debug)] //~ WARN unused attribute
   |     ^^^^^^^^^^^^^^^^

warning: unused attribute
  --> $DIR/issue-49934.rs:39:5
   |
LL |     #[derive(Debug)] //~ WARN unused attribute
   |     ^^^^^^^^^^^^^^^^

warning: unused attribute
  --> $DIR/issue-49934.rs:44:9
   |
LL |         #[derive(Debug)] //~ WARN unused attribute
   |         ^^^^^^^^^^^^^^^^