Commit Graph

5368 Commits

Author SHA1 Message Date
Ralf Jung
124fb1490a update Operand::Move docs 2023-07-11 21:59:01 +02:00
agnarrarendelle
dcfcc77282 fixed typos 2023-07-12 01:25:47 +08:00
lcnr
e386d410e0 remove unnecessary Rc 2023-07-11 15:10:21 +02:00
Erik Desjardins
d1e764cb3b aarch64-linux: properly handle 128bit aligned aggregates 2023-07-10 19:19:40 -04:00
Erik Desjardins
7e933b4e26 repr(align) <= 4 should still be byval 2023-07-10 19:19:40 -04:00
Erik Desjardins
00b3eca0df move has_repr to layout, handle repr(transparent) properly 2023-07-10 19:19:39 -04:00
Erik Desjardins
ed317e4a47 i686-windows: pass arguments with requested alignment > 4 indirectly 2023-07-10 19:19:38 -04:00
Santiago Pastorino
20429af7a3
Replace RPITIT current impl with new strategy that lowers as a GAT 2023-07-08 18:21:34 -03:00
bors
9bb6fbe261 Auto merge of #113376 - Nilstrieb:pointer-coercions-are-not-casts-because-that-sounds-way-to-general-aaaa, r=oli-obk
Rename `adjustment::PointerCast` and variants using it to `PointerCoercion`

It makes it sounds like the `ExprKind` and `Rvalue` are supposed to represent all pointer related casts, when in reality their just used to share a little enum variants. Make it clear there these are only coercions and that people who see this and think "why are so many pointer related casts not in these variants" aren't insane.

This enum was added in #59987. I'm not sure whether the variant sharing is actually worth it, but this at least makes it less confusing.

r? oli-obk
2023-07-08 13:48:30 +00:00
Michael Goulet
7a22c7e6f4
Rollup merge of #113467 - nbdd0121:unwind, r=compiler-errors
Fix comment of `fn_can_unwind`

Reopen of #113213
2023-07-07 22:12:19 -07:00
Nilstrieb
2beabbbf6f Rename adjustment::PointerCast and variants using it to PointerCoercion
It makes it sound like the `ExprKind` and `Rvalue` are supposed to represent all pointer related
casts, when in reality their just used to share a some enum variants. Make it clear there these
are only coercion to make it clear why only some pointer related "casts" are in the enum.
2023-07-07 18:17:16 +02:00
bors
cb80ff132a Auto merge of #113245 - lukas-code:unsizing-sanity-check, r=the8472
sanity check field offsets in unsizeable structs

As promised in https://github.com/rust-lang/rust/pull/112062#issuecomment-1567494994, this PR extends the layout sanity checks to ensure that structs fields don't move around when unsizing and prevent issues like https://github.com/rust-lang/rust/issues/112048 in the future. Like most other layout sanity checks, this only runs on compilers with debug assertions enabled.

Here is how it looks when it fails:
```text
error: internal compiler error: compiler/rustc_ty_utils/src/layout.rs:533:21: unsizing GcNode<std::boxed::Box<i32>> changed field order!
                                Layout { size: Size(32 bytes), align: AbiAndPrefAlign { abi: Align(8 bytes), pref: Align(8 bytes) }, abi: Aggregate { sized: true }, fields: Arbitrary { offsets: [Size(0 bytes), Size(8 bytes), Size(24 bytes)], memory_index: [0, 1, 2] }, largest_niche: Some(Niche { offset: Size(24 bytes), value: Pointer(AddressSpace(0)), valid_range: 1..=18446744073709551615 }), variants: Single { index: 0 } }
                                Layout { size: Size(24 bytes), align: AbiAndPrefAlign { abi: Align(8 bytes), pref: Align(8 bytes) }, abi: Aggregate { sized: false }, fields: Arbitrary { offsets: [Size(16 bytes), Size(0 bytes), Size(24 bytes)], memory_index: [1, 0, 2] }, largest_niche: None, variants: Single { index: 0 } }
```

r? `@the8472`
2023-07-07 15:42:29 +00:00
Michael Goulet
3f8919c09b get rid of a bit more calls to poly_select 2023-07-06 16:50:12 +00:00
Michael Goulet
52f7384995 Separate select calls that don't need a binder 2023-07-06 16:50:12 +00:00
Lukas Markeffsky
7aa5f39d3b add helper methods for accessing struct tail 2023-07-06 13:15:05 +00:00
Boxy
3fdb443e4e Add a new trait to Debug things with an infcx available 2023-07-06 11:36:39 +01:00
bors
4dd1719b34 Auto merge of #113377 - BoxyUwU:move_ty_ctors_to_ty, r=compiler-errors
Move `TyCtxt::mk_x` to `Ty::new_x` where applicable

Part of rust-lang/compiler-team#616

turns out there's a lot of places we construct `Ty` this is a ridiculously huge PR :S

r? `@oli-obk`
2023-07-06 08:10:42 +00:00
Oli Scherer
deda49e7b7 Fix up doc links 2023-07-06 07:32:08 +00:00
bors
bd8aabef31 Auto merge of #113291 - oli-obk:pretty_print_mir_const, r=RalfJung
Specialize `try_destructure_mir_constant` for its sole user (pretty printing)

We can't remove the query, as we need to invoke it from rustc_middle, but can only implement it in mir interpretation/const eval.

r? `@RalfJung` for a first round.

While we could move all the logic into pretty printing, that would end up duplicating a bit of code with const eval, which doesn't seem great either.
2023-07-06 00:00:38 +00:00
Michael Goulet
6ce1c89d64
Change comment on TyCtxt::mk_ty_from_kind 2023-07-05 13:58:04 -07:00
Boxy
12138b8e5e Move TyCtxt::mk_x to Ty::new_x where applicable 2023-07-05 20:27:07 +01:00
bors
5dac6b320b Auto merge of #113370 - compiler-errors:rollup-8gvyy8e, r=compiler-errors
Rollup of 8 pull requests

Successful merges:

 - #113010 (rust-installer & rls: remove exclusion from rustfmt & tidy )
 - #113317 ( -Ztrait-solver=next: stop depending on old solver)
 - #113319 (`TypeParameterDefinition` always require a `DefId`)
 - #113320 (Add some extra information to opaque type cycle errors)
 - #113321 (Move `ty::ConstKind` to `rustc_type_ir`)
 - #113337 (Winnow specialized impls during selection in new solver)
 - #113355 (Move most coverage code out of `rustc_codegen_ssa`)
 - #113356 (Add support for NetBSD/riscv64 aka. riscv64gc-unknown-netbsd.)

r? `@ghost`
`@rustbot` modify labels: rollup
2023-07-05 16:08:43 +00:00
Oli Scherer
e1e04a8bee Document magic boolean 2023-07-05 15:58:19 +00:00
Oli Scherer
8ac1a67d11 Name the destructure_mir_constant query appropriately 2023-07-05 15:54:43 +00:00
Oli Scherer
09b89efa70 Remove a function argument that is always passed with the same value. 2023-07-05 15:54:43 +00:00
Oli Scherer
a0eb348d38 Specialize DestructuredConstant to its one user (pretty printing) 2023-07-05 15:54:43 +00:00
Oli Scherer
4dcf988360 Specialize try_destructure_mir_constant for its sole user 2023-07-05 15:54:43 +00:00
Michael Goulet
c31fe41453
Rollup merge of #113337 - compiler-errors:next-solver-winnow-specializing, r=lcnr
Winnow specialized impls during selection in new solver

We need to be able to winnow impls that are specialized by more specific impls in order for codegen to be able to proceed.

r? ``@lcnr``
2023-07-05 08:45:45 -07:00
Michael Goulet
b2b1a50751
Rollup merge of #113321 - BoxyUwU:move_constkind_to_typeir, r=oli-obk
Move `ty::ConstKind` to `rustc_type_ir`

Needed this in another PR for custom debug impls, and this will also be required to move the new solver into a separate crate that does not use `TyCtxt` so that r-a and friends can depend on the trait solver.

Rebased on top of #113325, only the second and third commits needs reviewing
2023-07-05 08:45:45 -07:00
Michael Goulet
0334b64cbb
Rollup merge of #113320 - oli-obk:eval_obligation_query, r=petrochenkov,BoxyUwU
Add some extra information to opaque type cycle errors

Plus a bunch of cleanups.

This should help users debug query cycles due to auto trait checking. We'll probably want to fix cycle errors in most (or all?) cases by looking at the current item's hidden types (new solver does this), and by delaying the auto trait checks to after typeck.
2023-07-05 08:45:44 -07:00
bors
e4cd161006 Auto merge of #113210 - fee1-dead-contrib:effects-mvp, r=oli-obk
Effects/keyword generics MVP

This adds `feature(effects)`, which adds `const host: bool` to the generics of const functions, const traits and const impls. This will be used to replace the current logic around const traits.

r? `@oli-obk`
2023-07-05 13:42:00 +00:00
Boxy
62174bfe72 Deal with fallout 2023-07-05 09:46:30 +01:00
Boxy
8ac3ffe834 move ConstKind to typeir and move inherent impls to Const 2023-07-05 09:46:30 +01:00
Oli Scherer
9e98feb84c Add some extra information to opaque type cycle errors 2023-07-05 07:43:35 +00:00
Oli Scherer
ca581f9161 Don't require associated types with Self: Sized bounds in dyn Trait objects 2023-07-05 07:42:53 +00:00
Michael Goulet
d2a1803d6f Winnow specializing impls 2023-07-05 06:18:48 +00:00
Deadbeef
58c105af04 include host_effect_index in Generics 2023-07-04 17:21:52 +00:00
Boxy
d30f56dbf2 Replace const_error methods with Const::new_error 2023-07-04 14:46:32 +01:00
Boxy
ddbc774e74 Replace mk_const with Const::new_x methods 2023-07-04 14:26:33 +01:00
Deadbeef
8eb3e0bf30 enforce context effects in typeck 2023-07-04 11:47:46 +00:00
Michael Goulet
0c73b41cd6 remove TypeWellFormedFromEnv 2023-07-03 21:40:04 +00:00
Michael Goulet
810fbf086d Remove chalk from the compiler 2023-07-03 21:40:04 +00:00
lcnr
5378f07d64 use deeply_normalize for assumed_wf_types 2023-07-03 09:12:14 +02:00
lcnr
bd0d533d23 fix structurally relate for weak aliases 2023-07-03 09:12:14 +02:00
bors
4c3f8c728b Auto merge of #113256 - matthiaskrgr:rollup-poex8w2, r=matthiaskrgr
Rollup of 8 pull requests

Successful merges:

 - #113147 (Fix document examples of Vec::from_raw_parts and Vec::from_raw_parts_in)
 - #113202 (std docs: factorize literal in Barrier example)
 - #113228 (Migrate GUI colors test to original CSS color format)
 - #113231 (Fix `dropping_copy_types` lint from linting in match-arm with side-effects)
 - #113233 (Update chalk)
 - #113234 (Don't pass --test-args to `python -m unitest`)
 - #113244 (Make Rust Analyzer tests faster by compiling less code)
 - #113249 (Document tracking issue for rustdoc `show-type-layout`)

r? `@ghost`
`@rustbot` modify labels: rollup
2023-07-02 10:22:49 +00:00
Matthias Krüger
fda22efbf0
Rollup merge of #113233 - Nilstrieb:chaaalk, r=jackh726
Update chalk

For #109302

r? jackh726
2023-07-02 10:27:21 +02:00
bors
72b2101434 Auto merge of #112718 - oli-obk:SIMD-destructure_mir_const, r=cjgillot
Make simd_shuffle_indices use valtrees

This removes the second-to-last user of the `destructure_mir_constant` query. So in a follow-up we can remove the query and just move the query provider function directly into pretty printing (which is the last user).

cc `@rust-lang/clippy` there's a small functional change, but I think it is correct?
2023-07-02 07:43:36 +00:00
Nilstrieb
4be84771a7 Put FnAbiError behind reference to shrink result
The `FnAbi` is just a pointer, so the error type should not be bigger.
2023-07-01 21:16:27 +02:00
Nilstrieb
3019c1cb2a Put LayoutError behind reference to shrink result
`LayoutError` is 24 bytes, which is bigger than the `Ok` types, so let's
shrink that.
2023-07-01 21:16:25 +02:00
Nilstrieb
e43ec03968 Update chalk 2023-07-01 18:03:36 +02:00
Gary Guo
39c3ef799f Fix comment of fn_can_unwind 2023-06-30 18:38:56 +01:00
Matthias Krüger
42a495da7e
Rollup merge of #112670 - petrochenkov:typriv, r=eholk
privacy: Type privacy lints fixes and cleanups

See individual commits.
Follow up to https://github.com/rust-lang/rust/pull/111801.
2023-06-29 05:48:39 +02:00
Dylan DPC
fc2c587cd0
Rollup merge of #112867 - compiler-errors:more-impl-source-nits, r=lcnr
More `ImplSource` nits

Even more clean-ups, I'll put this up in parallel with the `select_in_new_trait_solver` PR.

r? ``@lcnr``
2023-06-28 18:28:47 +05:30
bors
8882507bc7 Auto merge of #112708 - flip1995:clippy-freezing-pc-with-ice, r=oli-obk
Avoid calling queries during query stack printing

This has the side effect, that when Clippy should ICE (during an EarlyPass?) it will fill up the RAM with 2 GB/s and then freezes my Laptop. This is blocking the Clippy sync and might give some people really bad experiences, so this should be merged ASAP.

r? `@cjgillot`
cc `@Zoxc`

I only commented this on [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/.60try_print_query_stack.60.20has.20.60ImplicitCtx.60.20during.20.60EarlyPass.60/near/363926180). I should've left a comment on the PR as well. My bad.
2023-06-28 09:40:07 +00:00
Oli Scherer
7c15779ff1 Rustdoc nit: refer to macro from docs 2023-06-28 07:07:16 +00:00
bors
6b46c996e1 Auto merge of #113105 - matthiaskrgr:rollup-rci0uym, r=matthiaskrgr
Rollup of 8 pull requests

Successful merges:

 - #112207 (Add trustzone and virtualization target features for aarch32.)
 - #112454 (Make compiletest aware of targets without dynamic linking)
 - #112628 (Allow comparing `Box`es with different allocators)
 - #112692 (Provide more context for `rustc +nightly -Zunstable-options` on stable)
 - #112972 (Make `UnwindAction::Continue` explicit in MIR dump)
 - #113020 (Add tests impl via obj unless denied)
 - #113084 (Simplify some conditions)
 - #113103 (Normalize types when applying uninhabited predicate.)

r? `@ghost`
`@rustbot` modify labels: rollup
2023-06-27 21:31:47 +00:00
Matthias Krüger
4b1d0682a6
Rollup merge of #113103 - cjgillot:normalize-inhabited, r=compiler-errors
Normalize types when applying uninhabited predicate.

Fixes https://github.com/rust-lang/rust/issues/112997
2023-06-27 22:10:16 +02:00
Matthias Krüger
d505582ce2
Rollup merge of #113084 - WaffleLapkin:less_map_or, r=Nilstrieb
Simplify some conditions

r? `@Nilstrieb`

Some things taken out of my `is_none_or` pr.
2023-06-27 22:10:15 +02:00
Matthias Krüger
9ec676dd7f
Rollup merge of #112972 - nbdd0121:mir, r=davidtwco
Make `UnwindAction::Continue` explicit in MIR dump

Makes it easier to spot unwinding related issues in MIR by making `UnwindAction::Continue` explicit, just like all other `UnwindAction`s.
2023-06-27 22:10:14 +02:00
Camille GILLOT
6f3f878351 Normalize types when applying uninhabited predicate. 2023-06-27 17:10:14 +00:00
Oli Scherer
b0142f603d
Avoid calling queries during query stack printing 2023-06-27 16:12:07 +02:00
Maybe Waffle
c60fb12a35 thir: Add Become expression kind 2023-06-27 09:03:05 +00:00
Maybe Waffle
ef05533c39 Simplify some conditions 2023-06-27 07:40:47 +00:00
bors
b5e51db16d Auto merge of #112938 - compiler-errors:clause-3, r=oli-obk
Migrate `TyCtxt::predicates_of` and `ParamEnv::caller_bounds` to `Clause`

The last big change in the series.

I will follow-up with additional filed issues once this PR lands:
- [ ] Investigate making `TypeFoldable<TyCtxt<'tcx>> for ty::Clause<'tcx>` implementation less weird: 2efe091705/compiler/rustc_middle/src/ty/structural_impls.rs (L672)
- [ ] Clean up the elaborator since it should only be emitting child clauses, not predicates
- [ ] Rename identifiers like `pred` and `predicates` to `clause` if they're actually clauses around the codebase
- [ ] Validate that all of the `ToPredicate` impls are acutally still needed, or prune them if they're not

r? `@ghost` until the other branch lands
2023-06-27 03:14:45 +00:00
bors
b9ad9b78a2 Auto merge of #112693 - ericmarkmartin:use-more-placeref, r=spastorino
Use PlaceRef abstractions more often

Associated issue: https://github.com/rust-lang/rust/issues/80647

r? `@spastorino`
2023-06-27 00:34:49 +00:00
Michael Goulet
374173cd99 TypeWellFormedInEnv 2023-06-26 23:12:04 +00:00
Michael Goulet
fbdef58414 Migrate predicates_of and caller_bounds to Clause 2023-06-26 23:12:03 +00:00
Oli Scherer
1c992c0b1c Assert that we don't convert unevaluated MIR promoteds to unevaluated type constants 2023-06-26 09:34:52 +00:00
Oli Scherer
168de14ac9 Make simd_shuffle_indices use valtrees 2023-06-26 09:34:52 +00:00
Eric Mark Martin
c07c10d1e4 use PlaceRef abstractions more consistently 2023-06-25 20:38:01 -04:00
bors
1d67eba687 Auto merge of #112891 - oli-obk:impl_trait_in_assoc_tys_cleanup, r=compiler-errors
Various impl trait in assoc tys cleanups

r? `@compiler-errors`

All commits except for the last are pure refactorings. 274dab5bd658c97886a8987340bf50ae57900c39 allows struct fields to participate in deciding whether a function has an opaque in its signature.

best reviewed commit by commit
2023-06-23 23:26:38 +00:00
Matthias Krüger
4e8983050e
Rollup merge of #112870 - compiler-errors:clause-2, r=oli-obk
Migrate `item_bounds` to `ty::Clause`

Should be simpler than the next PR that's coming up. Last three commits are the relevant ones.

r? ``@oli-obk`` or ``@lcnr``
2023-06-23 19:39:59 +02:00
Matthias Krüger
cea5ae00d2
Rollup merge of #112810 - compiler-errors:dont-ice-on-bad-layout, r=wesleywiser
Don't ICE on unnormalized struct tail in layout computation

1. We try to compute a `SizeSkeleton` even if a layout error occurs, but we really only need to do this if we get `LayoutError::Unknown`, since that means our type is too polymorphic to actually compute the full layout. If we have other errors, like `LayoutError::NormalizationError` or `LayoutError::Cycle`, then we can't really make any progress, since this represents an actual error.
2. Avoid using `normalize_erasing_regions` and `struct_tail_erasing_lifetimes` since those ICE on normalization errors, and since we may call `layout_of` in HIR typeck, we don't know for certain that we're on the happy path.

Fixes #112736
2023-06-23 19:39:58 +02:00
Gary Guo
c462291e0c Make UnwindAction::Continue explicit in MIR dump 2023-06-23 17:48:54 +01:00
Michael Goulet
471830b3a4 migrate inferred_outlives_of to Clause 2023-06-22 18:34:24 +00:00
Michael Goulet
2fa796a3c7 Expect clause more 2023-06-22 18:34:24 +00:00
Michael Goulet
46a650f4e0 Migrate item_bounds to ty::Clause 2023-06-22 18:34:23 +00:00
Oli Scherer
c8979e587b Move opaque_type_origin_unchecked onto TyCtxt and re-use it where it was open coded 2023-06-22 14:31:15 +00:00
bors
fa06a371b7 Auto merge of #112695 - nnethercote:inline-before-merging-cgus, r=wesleywiser
Inline before merging cgus

Because CGU merging relies on CGU sizes, but the CGU sizes before inlining aren't accurate.

This change doesn't have much effect on compile perf, but it makes follow-on changes that involve more sophisticated reasoning about CGU sizes much easier.

r? `@wesleywiser`
2023-06-22 08:34:32 +00:00
Nicholas Nethercote
abde9ba527 Tweak CGU size estimate code.
- Rename `create_size_estimate` as `compute_size_estimate`, because that
  makes more sense for the second and subsequent calls for each CGU.
- Change `CodegenUnit::size_estimate` from `Option<usize>` to `usize`.
  We can still assert that `compute_size_estimate` is called first.
- Move the size estimation for `place_mono_items` inside the function,
  for consistency with `merge_codegen_units`.
2023-06-22 09:33:06 +10:00
Santiago Pastorino
3ef510ca80
Print def_id on EarlyBoundRegion debug 2023-06-21 19:34:21 -03:00
Nicholas Nethercote
6f228e3420 Inline before merging CGUs.
Because CGU merging relies on CGU sizes, but the CGU sizes before
inlining aren't accurate.

This requires tweaking how the sizes are updated during merging: if CGU
A and B both have an inlined function F, then `size(A + B)` will be a
little less than `size(A) + size(B)`, because `A + B` will only have one
copy of F. Also, the minimum CGU size is increased because it now has to
account for inlined functions.

This change doesn't have much effect on compile perf, but it makes
follow-on changes that involve more sophisticated reasoning about CGU
sizes much easier.
2023-06-22 08:10:29 +10:00
Nilstrieb
a98c14f3a9
Rollup merge of #112772 - compiler-errors:clauses-1, r=lcnr
Add a fully fledged `Clause` type, rename old `Clause` to `ClauseKind`

Does two basic things before I put up a more delicate set of PRs (along the lines of #112714, but hopefully much cleaner) that migrate existing usages of `ty::Predicate` to `ty::Clause` (`predicates_of`/`item_bounds`/`ParamEnv::caller_bounds`).

1. Rename `Clause` to `ClauseKind`, so it's parallel with `PredicateKind`.
2. Add a new `Clause` type which is parallel to `Predicate`.
    * This type exposes `Clause::kind(self) -> Binder<'tcx, ClauseKind<'tcx>>` which is parallel to `Predicate::kind` 😸

The new `Clause` type essentially acts as a newtype wrapper around `Predicate` that asserts that it is specifically a `PredicateKind::Clause`. Turns out from experimentation[^1] that this is not negative performance-wise, which is wonderful, since this a much simpler design than something that requires encoding the discriminant into the alignment bits of a predicate kind, or something else like that...

r? ``@lcnr`` or ``@oli-obk``

[^1]: https://github.com/rust-lang/rust/pull/112714#issuecomment-1595653910
2023-06-21 07:37:01 +02:00
Nilstrieb
34c8e53d7a
Rollup merge of #112759 - cjgillot:closure-names, r=oli-obk
Make closure_saved_names_of_captured_variables a query.

As we will start removing debuginfo during MIR optimizations, we need to keep them somewhere.
2023-06-21 07:37:01 +02:00
bors
c55d1ee8d4 Auto merge of #112119 - zirconium-n:issue-113072-merge-borrow-kind, r=lcnr
Merge `BorrowKind::Unique` into `BorrowKind::Mut`

Fixes #112072

Might have conflict with #112070

r? `@lcnr`

I'm not sure what's the suitable change in a couple places.
2023-06-21 02:06:10 +00:00
Michael Goulet
7d0a5c31f5 yeet upcast_trait_def_id from ImplSourceObjectData 2023-06-20 23:33:02 +00:00
Michael Goulet
42571c4847 yeet ImplSource::TraitAlias too 2023-06-20 23:33:02 +00:00
bors
46514218f6 Auto merge of #112835 - lcnr:proof-tree-nits, r=BoxyUwU
proof tree nits

r? `@BoxyUwU`
2023-06-20 19:58:46 +00:00
Ziru Niu
b8a250fc4f update comment on MutBorrowKind::ClosureCapture 2023-06-20 20:55:31 +08:00
Ziru Niu
a52cc0a8c9 address most easy comments 2023-06-20 20:55:31 +08:00
Ziru Niu
8fb4c41f35 merge BorrowKind::Unique into BorrowKind::Mut 2023-06-20 20:55:31 +08:00
Guillaume Gomez
73496fc5d5
Rollup merge of #112786 - lcnr:early-binder, r=Nilstrieb
change binders from tuple structs to named fields
2023-06-20 14:23:40 +02:00
lcnr
f7472aa69e cleanup imports 2023-06-20 12:41:00 +02:00
bors
6fc0273b5a Auto merge of #112320 - compiler-errors:do-not-impl-via-obj, r=lcnr
Add `implement_via_object` to `rustc_deny_explicit_impl` to control object candidate assembly

Some built-in traits are special, since they are used to prove facts about the program that are important for later phases of compilation such as codegen and CTFE. For example, the `Unsize` trait is used to assert to the compiler that we are able to unsize a type into another type. It doesn't have any methods because it doesn't actually *instruct* the compiler how to do this unsizing, but this is later used (alongside an exhaustive match of combinations of unsizeable types) during codegen to generate unsize coercion code.

Due to this, these built-in traits are incompatible with the type erasure provided by object types. For example, the existence of `dyn Unsize<T>` does not mean that the compiler is able to unsize `Box<dyn Unsize<T>>` into `Box<T>`, since `Unsize` is a *witness* to the fact that a type can be unsized, and it doesn't actually encode that unsizing operation in its vtable as mentioned above.

The old trait solver gets around this fact by having complex control flow that never considers object bounds for certain built-in traits:
2f896da247/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs (L61-L132)

However, candidate assembly in the new solver is much more lovely, and I'd hate to add this list of opt-out cases into the new solver. Instead of maintaining this complex and hard-coded control flow, instead we can make this a property of the trait via a built-in attribute. We already have such a build attribute that's applied to every single trait that we care about: `rustc_deny_explicit_impl`. This PR adds `implement_via_object` as a meta-item to that attribute that allows us to opt a trait out of object-bound candidate assembly as well.

r? `@lcnr`
2023-06-20 08:42:37 +00:00
Michael Goulet
ca68cf0d46 Merge attrs, better validation 2023-06-20 04:38:55 +00:00
Michael Goulet
91e5c3f2e5 Make rustc_deny_explicit_impl only local as well 2023-06-20 04:38:46 +00:00
Michael Goulet
657d3f43a9 Add rustc_do_not_implement_via_object 2023-06-20 04:38:46 +00:00
Michael Goulet
31d1fbf8d2
Rollup merge of #112232 - fee1-dead-contrib:match-eq-const-msg, r=b-naber
Better error for non const `PartialEq` call generated by `match`

Resolves #90237
2023-06-19 17:53:33 -07:00
Michael Goulet
dd620aa73a Don't ICE on unnormalized struct tail in layout computation 2023-06-19 20:00:41 +00:00
bors
4051305389 Auto merge of #112238 - scottmcm:mir-add-unchecked, r=cjgillot
Promote unchecked integer math to MIR `BinOp`s

So slice indexing by a range gets down to one basic block, for example.

r? cjgillot
2023-06-19 17:14:21 +00:00