There should be a syntax trait covering `genericParameterClause` and `genericWhereClause`

[grynspan]

Description

There should be a syntax trait protocol covering genericParameterClause and genericWhereClause for the syntax types that have one or both of these properties. (IMHO a single protocol is the appropriate granularity rather than one for each property.)

[ahoppen]

Tracked in Apple’s issue tracker as rdar://110973434

[Matejkob]

If nobody's working on this issue I'd like to try solve it

[Matejkob]

@ahoppen That was a misclick; sorry XD. Can you reassign it?

[grynspan]

Thanks for taking a look!

[Matejkob]

Just to clarify, are we focusing only on the creation of a syntax trait, as shown below:

Trait(
  traitName: "WithGenericParameterAndWhereClause",
  documentation: """
    Represents a syntax node that has an optional `genericParameterClause` and `genericWhereClause` children.

    For example, functions or types like class or struct can be generic and have a where clause in Swift.
    """,
  children: [
    Child(name: "GenericParameterClause", kind: .node(kind: .genericParameterClause), isOptional: true),
    Child(name: "GenericWhereClause", kind: .node(kind: .genericWhereClause), isOptional: true)
  ]
),

and then extending each declaration node, with this trait, which has genericParameterClause and genericWhereClause children? We don't need to apply this new trait in the code currently, correct?

If my understanding of the issue is accurate, what is your opinion on the suggested trait name and its documentation?

[ahoppen]

I would name it WithGenericParameters.

Regarding documentation, I would write something like the following.

For the node

Syntax nodes that have generic parameters.

For example, functions or nominal types like `class` or `struct` can have generic parameters and have a generic where clause that restricts these generic parameters.

For GenericParameterClause:

The parameter clause that defines the generic parameters.

For GenericWhereClause:

A `where` clause that places additional constraints on generic parameters like `where Element: Hashable`.

And if you want to, I think it would make sense to add very similar comments to the GenericParameterClause and GenericWhereClause types.

[Matejkob]

How about we also add a similar comment to all children nodes of kinds GenericParameterClause and GenericWhereClause in all declaration nodes?

Or do you prefer adding documentation to a whole node at a time?

[ahoppen]

I was just about to suggest that. I was briefly considering whether we should automatically inherit the documentation from the trait but explicitly adding it to the children of the nodes seems like the better option to me.

[Matejkob]

I've also been considering some sort of automation for this case. I'm unsure if inheritance would be the best approach. Perhaps it would be more efficient to centralize declaration documentation content in one location, and then inject it into each node using the Localizable feature or by assigning it to properties, or via some other pattern. Copying and pasting the same string to different nodes seems highly unproductive and could easily lead to inconsistencies if someone decides to modify the content of the documentation and forget to update it in all places.