`ty.kind()` -> `ty.data()`

[nikomatsakis]

Proposal

• Rename ty.kind() and similar methods to ty.data() -- the data method, more generally, would be used to get from the interned thing to data that was interned
• Rename TyKind to TyData
• Same for other types

This matches the chalk naming scheme. There are two main advantages:

• the term Kind also has a meaning in type theory, where it refers to the "kinds" of generic arguments one can have (e.g., types, lifetimes, constants)
• the term Kind doesn't apply to all the things we would like to intern, such as slices of types and so forth

The eventual goal of extracting a shared type library is that we should be able to work generically with all interned types (to allow for alternative interning schemes), and in that case we need a generic term to access their "data".

Mentors or Reviewers

@LeSeulArtichaut is willing to do the impl work, and @nikomatsakis can review.

Process

The main points of the Major Change Process is as follows:

• File an issue describing the proposal.
• A compiler team member or contributor who is knowledgeable in the area can second by writing @rustbot second.
  • Finding a "second" suffices for internal changes. If however you are proposing a new public-facing feature, such as a -C flag, then full team check-off is required.
  • Compiler team members can initiate a check-off via @rfcbot fcp merge on either the MCP or the PR.
• Once an MCP is seconded, the Final Comment Period begins. If no objections are raised after 10 days, the MCP is considered approved.

You can read more about Major Change Proposals on forge.

Comments

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[rustbot]

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[eddyb]

@rustbot second

[LeSeulArtichaut]

Note: there have been concerns raised on the associated Zulip topic, this should probably not be accepted yet.

[spastorino]

@nikomatsakis how should we proceed here? maybe remove final-comment-period and have somebody seconding this again when there are no more concerns?.

[nikomatsakis]

Given the concerns that were raised and recent discussion in the traits working group, I'm going to close this issue. We're considering two things now:

• first off, there's a bunch of other work we can pursue, and we can defer this particular change
• second, we may wish to have data() yield a TyData that is actually corresponding to TyS, and leave TyKind the same