While many programmers may intuitively appreciate the significance of
"magic numbers" like −2147483648, Rust is about empowering everyone to
build reliable and efficient software! It's a bit more legible to
print the constant names (even noisy fully-qualified-paths thereof).
The bit-manipulation methods mirror those in
`librustc_mir::hair::pattern::_match::all_constructors`; thanks to the
immortal Varkor for guidance.
Resolves#56393.
CTFE: simplify ConstValue by not checking for alignment
I hope the test suite actually covers the problematic cases here?
r? @oli-obk
Fixes https://github.com/rust-lang/rust/issues/61952
Miri: dispatch first on the type
Based on the fact that Miri now always has intptrcast available, we can change binops and casts to first check the type of the source operand and then decide based on that what to do, instead of considering the value (pointer vs bits) first.
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
clarify and unify some type test names
* `is_mutable_pointer`: use `ptr` suffix for consistency with `is_region_ptr`, `is_fn_ptr`, `is_unsafe_ptr`.
* `is_pointer_sized`: the name is misleading as this only tests for pointer-sized *integers*, so rename to `is_ptr_sized_integral`.
rustc: precompute the largest Niche and store it in LayoutDetails.
Since we only ever can use at most one niche, it makes sense to just store that in the layout, for the simplest caching (especially as it's almost trivial to compute).
There might be a speedup from this, but even if it's marginal now, the caching would be a more significant benefit for future optimization attempts.
Stabilize the type_name intrinsic in core::any
Stabilize `type_name` in `core::any`.
Closesrust-lang/rfcs#1428
FCP completed over there.
`RELEASES.md`: Prefer T-libs for categorization.
Use sharded maps for interning
Cuts down runtime from 5.5s to 3.8s for non-incremental `syntex_syntax` check builds with 16 threads / 8 cores.
r? @eddyb
Make struct_tail normalize when possible
As noted in commit message: this replaces the existing methods to extract the struct tail(s) with new entry points that make the handling of normalization explicit.
Most of the places that call `struct_tail` are during codegen, post type-checking, and therefore they can get away with using `tcx.normalize_erasing_regions` (this is the entry point `struct_tail_erasing_lifetimes`)
For other cases that may arise, one can use the core method, which is parameterized over the normalization `Ty -> Ty` closure (`struct_tail_with_normalize`).
Or one can use the trivial entry point that does not normalization (`struct_tail_without_normalization`)
----
I spent a little while trying to make a test that exposed the bug via `impl Trait` rather than a projection, but I failed to find something that tripped up the current nightly `rustc`.
* I have *not* spent any time trying to make tests that trip up the other places where `struct_tail` was previously being called. While I do think the task of making such tests could be worthwhile, I am simply running out of time. (Its also possible that the layout code is always the first point called, and thus it may be pointless to try to come up with such tests.)
I also spent a little time discussing with @eddyb where this code should live. They suggested moving `struct_tail` and its sibling `struct_lockstep_tails` to the `LayoutCx`. But in the interest of time, I have left that refactoring (which may be questionable at this point) to a follow-up task.
----
Fix#60431
The old struct tail functions did not deal with `<T as Trait>::A` and `impl
Trait`, at least not explicitly. (We didn't notice this bug before because it
is only exposed when the tail (post deep normalization) is not `Sized`, so it
was a rare case to deal with.)
For post type-checking (i.e. during codegen), there is now
`struct_tail_erasing_lifetimes` and `struct_lockstep_tails_erasing_lifetimes`,
which each take an additional `ParamEnv` argument to drive normalization.
For pre type-checking cases where normalization is not needed, there is
`struct_tail_without_normalization`. (Currently, the only instance of this is
`Expectation::rvalue_hint`.)
All of these new entrypoints work by calling out to common helper routines.
The helpers are parameterized over a closure that handles the normalization.
Creating a fresh expansion and immediately generating a span from it is the most common scenario.
Also avoid allocating `allow_internal_unstable` lists for derive markers repeatedly.
And rename `ExpnInfo::with_unstable` to `ExpnInfo::allow_unstable`, seems to be a better fitting name.
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
