Personally, using macros in place of actually generated code sounds awful. It lacks all inspectability and debugability. If that's what we want here an actual integrated code generator would be much better. These type of Rust-like macros make code essentially unintelligible and just as magic as having the compiler generate it. The only reason the status quo is really viable is that no one really needs to inspect the contents of a generated Equatable or Codable conformance given how rote and similar they are.
If we do want such capabilities, it should not be enabled by yet another new syntax. I should be able to make my macros look like normal capabilities, like @Traced or something like that.