updated the RFC

0000-template.md

@@ -4,27 +4,44 @@
 - Rust Issue: (leave this empty)
 
 # Summary
+[summary]: #summary
 
 One para explanation of the feature.
 
 # Motivation
+[motivation]: #motivation
 
 Why are we doing this? What use cases does it support? What is the expected outcome?
 
 # Detailed design
+[design]: #detailed-design
 
 This is the bulk of the RFC. Explain the design in enough detail for somebody familiar
 with the language to understand, and for somebody familiar with the compiler to implement.
 This should get into specifics and corner-cases, and include examples of how the feature is used.
 
+# How We Teach This
+[how-we-teach-this]: #how-we-teach-this
+
+What names and terminology work best for these concepts and why? 
+How is this idea best presented—as a continuation of existing Rust patterns, or as a wholly new one?
+
+Would the acceptance of this proposal change how Rust is taught to new users at any level? 
+How should this feature be introduced and taught to existing Rust users?
+
+What additions or changes to the Rust Reference, _The Rust Programming Language_, and/or _Rust by Example_ does it entail?
+
 # Drawbacks
+[drawbacks]: #drawbacks
 
 Why should we *not* do this?
 
 # Alternatives
+[alternatives]: #alternatives
 
 What other designs have been considered? What is the impact of not doing this?
 
 # Unresolved questions
+[unresolved]: #unresolved-questions
 
 What parts of the design are still TBD?

compiler_changes.md

@@ -0,0 +1,53 @@
+# RFC policy - the compiler
+
+We have not previously had an RFC system for compiler changes, so policy here is
+likely to change as we get the hang of things. We don't want to slow down most
+compiler development, but on the other hand we do want to do more design work
+ahead of time on large additions and refactorings.
+
+Compiler RFCs will be managed by the compiler sub-team, and tagged `T-compiler`.
+The compiler sub-team will do an initial triage of new PRs within a week of
+submission. The result of triage will either be that the PR is assigned to a
+member of the sub-team for shepherding, the PR is closed because the sub-team
+believe it should be done without an RFC, or closed because the sub-team feel it
+should clearly not be done and further discussion is not necessary. We'll follow
+the standard procedure for shepherding, final comment period, etc.
+
+Where there is significant design work for the implementation of a language
+feature, the preferred workflow is to submit two RFCs - one for the language
+design and one for the implementation design. The implementation RFC may be
+submitted later if there is scope for large changes to the language RFC.
+
+
+## Changes which need an RFC
+
+* New lints (these fall under the lang team)
+* Large refactorings or redesigns of the compiler
+* Changing the API presented to syntax extensions or other compiler plugins in
+  non-trivial ways
+* Adding, removing, or changing a stable compiler flag
+* The implementation of new language features where there is significant change
+  or addition to the compiler. There is obviously some room for interpretation
+  about what consitutes a "significant" change and how much detail the
+  implementation RFC needs. For guidance, [associated items](text/0195-associated-items.md)
+  and [UFCS](text/0132-ufcs.md) would clearly need an implementation RFC,
+  [type ascription](text/0803-type-ascription.md) and
+  [lifetime elision](text/0141-lifetime-elision.md) would not.
+* Any other change which causes backwards incompatible changes to stable
+  behaviour of the compiler, language, or libraries
+
+
+## Changes which don't need an RFC
+
+* Bug fixes, improved error messages, etc.
+* Minor refactoring/tidying up
+* Implmenting language features which have an accepted RFC, where the
+  implementation does not significantly change the compiler or require
+  significant new design work
+* Adding unstable API for tools (note that all compiler API is currently unstable)
+* Adding, removing, or changing an unstable compiler flag (if the compiler flag
+  is widely used there should be at least some discussion on discuss, or an RFC
+  in some cases)
+
+If in doubt it is probably best to just announce the change you want to make to
+the compiler subteam on discuss or IRC, and see if anyone feels it needs an RFC.

lang_changes.md

@@ -0,0 +1,38 @@
+# RFC policy - language design
+
+Pretty much every change to the language needs an RFC. Note that new
+lints (or major changes to an existing lint) are considered changes to
+the language.
+
+Language RFCs are managed by the language sub-team, and tagged `T-lang`. The
+language sub-team will do an initial triage of new PRs within a week of
+submission. The result of triage will either be that the PR is assigned to a
+member of the sub-team for shepherding, the PR is closed as postponed because
+the subteam believe it might be a good idea, but is not currently aligned with
+Rust's priorities, or the PR is closed because the sub-team feel it should
+clearly not be done and further discussion is not necessary. In the latter two
+cases, the sub-team will give a detailed explanation. We'll follow the standard
+procedure for shepherding, final comment period, etc.
+
+
+## Amendments
+
+Sometimes in the implementation of an RFC, changes are required. In general
+these don't require an RFC as long as they are very minor and in the spirit of
+the accepted RFC (essentially bug fixes). In this case implementers should
+submit an RFC PR which amends the accepted RFC with the new details. Although
+the RFC repository is not intended as a reference manual, it is preferred that
+RFCs do reflect what was actually implemented. Amendment RFCs will go through
+the same process as regular RFCs, but should be less controversial and thus
+should move more quickly.
+
+When a change is more dramatic, it is better to create a new RFC. The RFC should
+be standalone and reference the original, rather than modifying the existing
+RFC. You should add a comment to the original RFC with referencing the new RFC
+as part of the PR.
+
+Obviously there is some scope for judgment here. As a guideline, if a change
+affects more than one part of the RFC (i.e., is a non-local change), affects the
+applicability of the RFC to its motivating use cases, or there are multiple
+possible new solutions, then the feature is probably not 'minor' and should get
+a new RFC.

libs_changes.md

@@ -0,0 +1,114 @@
+# RFC guidelines - libraries sub-team
+
+# Motivation
+
+* RFCs are heavyweight:
+    * RFCs generally take at minimum 2 weeks from posting to land. In
+      practice it can be more on the order of months for particularly
+      controversial changes.
+    * RFCs are a lot of effort to write; especially for non-native speakers or
+      for members of the community whose strengths are more technical than literary.
+    * RFCs may involve pre-RFCs and several rewrites to accommodate feedback.
+    * RFCs require a dedicated shepherd to herd the community and author towards
+      consensus.
+    * RFCs require review from a majority of the subteam, as well as an official
+      vote.
+    * RFCs can't be downgraded based on their complexity. Full process always applies.
+      Easy RFCs may certainly land faster, though.
+    * RFCs can be very abstract and hard to grok the consequences of (no implementation).
+
+* PRs are low *overhead* but potentially expensive nonetheless:
+    * Easy PRs can get insta-merged by any rust-lang contributor.
+    * Harder PRs can be easily escalated. You can ping subject-matter experts for second
+      opinions. Ping the whole team!
+    * Easier to grok the full consequences. Lots of tests and Crater to save the day.
+    * PRs can be accepted optimistically with bors, buildbot, and the trains to guard
+      us from major mistakes making it into stable. The size of the nightly community
+      at this point in time can still mean major community breakage regardless of trains,
+      however.
+    * HOWEVER: Big PRs can be a lot of work to make only to have that work rejected for
+      details that could have been hashed out first.
+
+* RFCs are *only* meaningful if a significant and diverse portion of the
+community actively   participates in them. The official teams are not
+sufficiently diverse to establish   meaningful community consensus by agreeing
+amongst themselves.
+
+* If there are *tons* of RFCs -- especially trivial ones -- people are less
+likely to engage with them. Official team members are super busy. Domain experts
+and industry professionals are super busy *and* have no responsibility to engage
+in RFCs. Since these are *exactly* the most important people to get involved in
+the RFC process, it is important that we be maximally friendly towards their
+needs.
+
+
+# Is an RFC required?
+
+The overarching philosophy is: *do whatever is easiest*. If an RFC
+would be less work than an implementation, that's a good sign that an RFC is
+necessary. That said, if you anticipate controversy, you might want to short-circuit
+straight to an RFC. For instance new APIs almost certainly merit an RFC. Especially
+as `std` has become more conservative in favour of the much more agile cargoverse.
+
+* **Submit a PR** if the change is a:
+    * Bugfix
+    * Docfix
+    * Obvious API hole patch, such as adding an API from one type to a symmetric type.
+      e.g. `Vec<T> -> Box<[T]>` clearly motivates adding `String -> Box<str>`
+    * Minor tweak to an unstable API (renaming, generalizing)
+    * Implementing an "obvious" trait like Clone/Debug/etc
+* **Submit an RFC** if the change is a:
+    * New API
+    * Semantic Change to a stable API
+    * Generalization of a stable API (e.g. how we added Pattern or Borrow)
+    * Deprecation of a stable API
+    * Nontrivial trait impl (because all trait impls are insta-stable)
+* **Do the easier thing** if uncertain. (choosing a path is not final)
+
+
+# Non-RFC process
+
+* A (non-RFC) PR is likely to be **closed** if clearly not acceptable:
+    * Disproportionate breaking change (small inference breakage may be acceptable)
+    * Unsound
+    * Doesn't fit our general design philosophy around the problem
+    * Better as a crate
+    * Too marginal for std
+    * Significant implementation problems
+
+* A PR may also be closed because an RFC is approriate.
+
+* A (non-RFC) PR  may be **merged as unstable**. In this case, the feature
+should have a fresh feature gate and an associated tracking issue for
+stabilisation. Note that trait impls and docs are insta-stable and thus have no
+tracking issue. This may imply requiring a higher level of scrutiny for such
+changes.
+
+However, an accepted RFC is not a rubber-stamp for merging an implementation PR.
+Nor must an implementation PR perfectly match the RFC text. Implementation details
+may merit deviations, though obviously they should be justified. The RFC may be
+amended if deviations are substantial, but are not generally necessary. RFCs should
+favour immutability. The RFC + Issue + PR should form a total explanation of the
+current implementation.
+
+* Once something has been merged as unstable, a shepherd should be assigned
+  to promote and obtain feedback on the design.
+
+* Every time a release cycle ends, the libs teams assesses the current unstable
+  APIs and selects some number of them for potential stabilization during the
+  next cycle. These are announced for FCP at the beginning of the cycle, and
+  (possibly) stabilized just before the beta is cut.
+
+* After the final comment period, an API should ideally take one of two paths:
+  * **Stabilize** if the change is desired, and consensus is reached
+  * **Deprecate** is the change is undesired, and consensus is reached
+  * **Extend the FCP** is the change cannot meet consensus
+    * If consensus *still* can't be reached, consider requiring a new RFC or
+      just deprecating as "too controversial for std".
+
+* If any problems are found with a newly stabilized API during its beta period,
+  *strongly* favour reverting stability in order to prevent stabilizing a bad
+  API. Due to the speed of the trains, this is not a serious delay (~2-3 months
+  if it's not a major problem).
+
+