Change opaque type syntax from `existential type` to type alias `impl Trait`
This implements a new feature gate `type_alias_impl_trait` (this is slightly different from the originally proposed feature name, but matches what has been used in discussion since), deprecating the old `existential_types` feature.
The syntax for opaque types has been changed. In addition, the "existential" terminology has been replaced with "opaque", as per previous discussion and the RFC.
This makes partial progress towards implementing https://github.com/rust-lang/rust/issues/63063.
r? @Centril
Now that procedural macros no longer link transitively to libsyntax,
this shouldn't be needed any more! This commit is an experiment in
removing all dynamic libraries from rustc except for librustc_driver
itself. Let's see how far we can get with that!
The (almost) culmination of HirIdification
It's finally over.
This PR removes old `FIXME`s and renames some functions so that the `HirId` variant has the shorter name.
All that remains (and rightfully so) is stuff in `resolve`, `save_analysis` and (as far as I can tell) in a few places where we can't replace `NodeId` with `HirId`.
Implement another internal lints
cc #49509
This adds ~~two~~ one internal lint~~s~~:
1. LINT_PASS_IMPL_WITHOUT_MACRO: Make sure, that the `{declare,impl}_lint_pass` macro is used to implement lint passes. cc #59669
2. ~~USAGE_OF_TYCTXT_AND_SPAN_ARGS: item 2 on the list in #49509~~
~~With 2. I wasn't sure, if this lint should be applied everywhere. That means a careful review of 0955835 would be great. Also 73fb9b4 allows this lint on some functions. Should I also apply this lint there?~~
TODO (not directly relevant for review):
- [ ] https://github.com/rust-lang/rust/pull/59316#discussion_r280186517 (not sure yet, if this works or how to query for `rustc_private`, since it's not in [`Features`](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/feature_gate/struct.Features.html) 🤔 cc @eddyb)
- [x] https://github.com/rust-lang/rust/pull/61735#discussion_r292389870
- [x] Check explicitly for the `{declare,impl}_lint_pass!` macros
r? @oli-obk
Add a query type which is always marked as red if it runs
This is useful for queries which produce results which are very likely to change if their inputs do.
I also expect this to be useful for end to end queries because 1) we don't need `HashStable` impls and 2) we avoid the overhead of hashing the result of large results like the AST or the HIR map.
r? @michaelwoerister
