error[E0119]: conflicting implementations of trait `Drop` for type `MyStruct`
  --> tests/derive_macro_tests/invalid_drop_impl.rs:3:10
   |
3  | #[derive(Trace)]
   |          ^^^^^ conflicting implementation for `MyStruct`
...
11 | impl Drop for MyStruct {
   | ---------------------- first implementation here
   |
   = note: this error originates in the derive macro `Trace` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0119]: conflicting implementations of trait `Drop` for type `MyEnum`
  --> tests/derive_macro_tests/invalid_drop_impl.rs:16:10
   |
16 | #[derive(Trace)]
   |          ^^^^^ conflicting implementation for `MyEnum`
...
25 | impl Drop for MyEnum {
   | -------------------- first implementation here
   |
   = note: this error originates in the derive macro `Trace` (in Nightly builds, run with -Z macro-backtrace for more info)