error[E0428]: the name `Dealigned` is defined multiple times
  --> $DIR/multiple_definitions_attribute_merging.rs:17:1
   |
LL | struct Dealigned<T>(u8, T);
   | --------------------------- previous definition of the type `Dealigned` here
...
LL | struct Dealigned<T>(u8, T);
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ `Dealigned` redefined here
   |
   = error: internal compiler error: compiler/rustc_mir_transform/src/check_packed_ref.rs:LL:CC: builtin derive created an unaligned reference
  --> $DIR/multiple_definitions_attribute_merging.rs:17:25
   |
LL | #[derive(PartialEq)]
   |          --------- in this derive macro expansion
LL | #[repr(C)]
LL | struct Dealigned<T>(u8, T);
   |                         ^
   |
   = Box<dyn Any>
query stack during panic:
#0 [mir_built] building MIR for `<impl at $DIR/multiple_definitions_attribute_merging.rs:15:10: 15:19>::eq`
#1 [check_unsafety] unsafety-checking `<impl at $DIR/multiple_definitions_attribute_merging.rs:15:10: 15:19>::eq`
end of query stack
error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0428`.