Introduce StructImplementation and associated methods

[Thunkar]

Problem

Currently there's only StructDefinition. Sometimes it is useful to manipulate a struct's impl, much like TraitImplementation (mostly to add methods).

Happy Case

Something like this can be done:

comptime fn get_imp(s: StructDefinition) {
  let implementation = s.get_impl();
  let methods = implementation.methods();
  let new_method = ...;
  implementation.set_methods(methods.push_back(new_method));
}

Workaround

None

Workaround Description

No response

Additional Context

No response

Project Impact

Blocker

Blocker Context

No response

Would you like to submit a PR for this Issue?

None

Support Needs

No response

[jfecher]

Sometimes it is useful to manipulate a struct's impl, much like TraitImplementation (mostly to add methods).

I think this use case may be covered by allowing unquoting impls at top-level once #5927 is merged:

comptime fn get_imp(s: StructDefinition) -> Quoted {
  let t = s.as_type();
  let generics = s.generics()
    .map(|g| quote { $g })
    .join(quote {,});

  quote {
      impl<$generics> $t {
          pub fn my_new_method(self) { ... }
      }
  }
}

[asterite]

Fixed by #5927