coverage: Add enums to accommodate other kinds of coverage mappings
Extracted from #118305.
LLVM supports several different kinds of coverage mapping regions, but currently we only ever emit ordinary “code” regions. This PR performs the plumbing required to add other kinds of regions as enum variants, but does not add any specific variants other than `Code`.
The main motivation for this change is branch coverage, but it will also allow separate experimentation with gap regions and skipped regions, which might help in producing more accurate and useful coverage reports.
---
``@rustbot`` label +A-code-coverage
Remove `DiagnosticBuilder::buffer`
`DiagnosticBuilder::buffer` doesn't do much, and part of what it does (for `-Ztreat-err-as-bug`) it shouldn't.
This PR strips it back, replaces its uses, and finally removes it, making a few cleanups in the vicinity along the way.
r? ``@oli-obk``
Silence some follow-up errors [2/x]
this is one piece of the requested cleanups from https://github.com/rust-lang/rust/pull/117449
the `type_of` query frequently uses astconv to convert a `hir::Ty` to a `ty::Ty`. This process is infallible, but may produce errors as it goes. All the error reporting sites that had access to the `ItemCtxt` are now tainting it, causing `type_of` to return a `ty::Error` instead of anything else.
annotate-snippets: update to 0.10
Ports `annotate-snippets` to 0.10, temporary dupes versions; other crates left that depends on 0.9 is `ui_test` and `rustfmt`.
Remove a large amount of leb128-coded integers
This removes ~41%[^1] of the leb128-encoded integers serialized during libcore compilation by changing enum tags to opportunistically use `u8` where feasible instead of the leb128 coding via `usize`.
This should have effectively zero impact on metadata file sizes, since almost all or all enum tags fit into the 7 bits available in leb128 for single-byte encodings. Perf results indicate this is basically neutral across the board except for an improvement in bootstrap time.
[^1]: More than half the remaining integers still fit into <= 128, so the leb128 coding still makes sense. 32% are zero, and 46% are <= 4.
One consequence is that errors returned by
`maybe_new_parser_from_source_str` now must be consumed, so a bunch of
places that previously ignored those errors now cancel them. (Most of
them explicitly dropped the errors before. I guess that was to indicate
"we are explicitly ignoring these", though I'm not 100% sure.)
Stop mentioning internal lang items in no_std binary errors
When writing a no_std binary, you'll be greeted with nonsensical errors mentioning lang items like eh_personality and start. That's pretty bad because it makes you think that you need to define them somewhere! But oh no, now you're getting the `internal_features` lint telling you that you shouldn't use them! But you need a no_std binary! What now?
No problem! Writing a no_std binary is super easy. Just use panic=abort and supply your own platform specific entrypoint symbol (like `main`) and you're good to go. Would be nice if the compiler told you that, right?
This makes it so that it does do that.
I don't _love_ the new messages yet, but they're decent I think. They can probably be improved, please suggest improvements.
Two different lifetimes are conflated. This doesn't matter right now,
but needs to be fixed for the next commit to work. And the more
descriptive lifetime names make the code easier to read.
But we can't easily switch from `Vec<Diagnostic>` to
`Vec<DiagnosticBuilder<G>>` because there's a mix of errors and warnings
which result in different `G` types. So we must make
`DiagnosticBuilder::into_diagnostic` public, but that's ok, and it will
get more use in subsequent commits.
Each of these has a single call site: `source_file_to_parser`,
`try_file_to_source_file`, `file_to_source_file`. Having them separate
just makes the code longer and harder to read.
Also, `maybe_file_to_stream` doesn't need to be `pub`.
It seems very wrong to have a `-Ztreat-err-as-bug` check here before the
error is even emitted.
Once that's done:
- `into_diagnostic` is infallible, so its return type doesn't need the
`Option`;
- the `&'a DiagCtxt` also isn't needed, because only one callsite uses
it, and it already have access to it via `self.dcx`;
- the comments about dcx disabling buffering are no longer true, this is
unconditional now;
- and the `debug!` seems unnecessary... the comment greatly overstates
its importance because few diagnostics come through `into_diagnostic`,
and `-Ztrack-diagnostics` exists anyway.
Errors in `DiagCtxtInner::emit_diagnostic` are never set to
`Level::Bug`, because the condition never succeeds, because
`self.treat_err_as_bug()` is called *before* the error counts are
incremented.
This commit switches to `self.treat_next_err_as_bug()`, fixing the
problem. This changes the error message output to actually say "internal
compiler error".
This is less elegant in some ways, since we no longer visit a BCB's spans as a
batch, but will make it much easier to add support for other kinds of coverage
mapping regions (e.g. branch regions or gap regions).
Reorder early post-inlining passes.
`RemoveZsts`, `RemoveUnneededDrops` and `UninhabitedEnumBranching` only depend on types, so they should be executed together early after MIR inlining introduces those types.
This does not change the end-result, but this makes the pipeline a bit more consistent.
Rollup of 11 pull requests
Successful merges:
- #115046 (Use version-sorting for all sorting)
- #118915 (Add some comments, add `can_define_opaque_ty` check to `try_normalize_ty_recur`)
- #119006 (Fix is_global special address handling)
- #119637 (Pass LLVM error message back to pass wrapper.)
- #119715 (Exhaustiveness: abort on type error)
- #119763 (Cleanup things in and around `Diagnostic`)
- #119788 (change function name in comments)
- #119790 (Fix all_trait* methods to return all traits available in StableMIR)
- #119803 (Silence some follow-up errors [1/x])
- #119804 (Stabilize mutex_unpoison feature)
- #119832 (Meta: Add project const traits to triagebot config)
r? `@ghost`
`@rustbot` modify labels: rollup
Silence some follow-up errors [1/x]
this is one piece of the requested cleanups from https://github.com/rust-lang/rust/pull/117449
When we use `-> impl SomeTrait<_>` as a return type, we are both using the "infer return type suggestion" code path, and the infer opaque type code path within the same function. That can lead to confusing diagnostics, so silence all opaque type diagnostics in that case.
Cleanup things in and around `Diagnostic`
These changes all arose when I was looking closely at how to simplify `DiagCtxtInner::emit_diagnostic`.
r? `@compiler-errors`
Pass LLVM error message back to pass wrapper.
When rustc fails to load a plugin, it should provide more detailed error message. Before this PR, rustc prints:
```
error: failed to run LLVM passes: Failed to load pass pluginPLUGIN_NAME.so
```
This PR passes LLVM errors back to rustc. After this PR, rustc prints:
```
error: failed to run LLVM passes: Could not load library 'PLUGIN_NAME.so': PLUGIN_NAME.so: undefined symbol: _ZN4llvm9DebugFlagE
```
This PR only contains usability improvements and does not change any functionality. Thus, no new unit test is implemented.
Exhaustiveness: use an `Option` instead of allocating fictitious patterns
In the process of exhaustiveness checking, `Matrix` stores a 2D array of patterns. Those are subpatterns of the patterns we were provided as input, _except_ sometimes we allocate some extra wildcard patterns to fill a hole during specialization.
Morally though, we could store `Option<&'p DeconstructedPat>` in the matrix, where `None` signifies a wildcard. That way we'd only have "real" patterns in the matrix and we wouldn't need the arena to allocate these wildcards. This is what this PR does.
This is part of me splitting up https://github.com/rust-lang/rust/pull/119581 for ease of review.
r? `@compiler-errors`
Of the error levels satisfying `is_error`, `Level::Error` is the only
one that can be a lint, so there's no need to check for it.
(And even if it wasn't, it would make more sense to include
non-`Error`-but-`is_error` lints under `lint_err_count` than under
`err_count`.)
There are four functions that adjust error and warning counts:
- `stash_diagnostic` (increment)
- `steal_diagnostic` (decrement)
- `emit_stashed_diagnostics) (decrement)
- `emit_diagnostic` (increment)
The first three all behave similarly, and only update `warn_count` for
forced warnings. But the last one updates `warn_count` for both forced
and non-forced warnings.
Seems like a bug. How should it be fixed? Well, `warn_count` is only
used in one place: `DiagCtxtInner::drop`, where it's part of the
condition relating to the printing of `good_path_delayed_bugs`. The
intention of that condition seems to be "have any errors been printed?"
so this commit replaces `warn_count` with `has_printed`, which is set
when printing occurs. This is simpler than all the ahead-of-time
incrementing and decrementing.
`is_force_warn` is only possible for diagnostics with `Level::Warning`,
but it is currently stored in `Diagnostic::code`, which every diagnostic
has.
This commit:
- removes the boolean `DiagnosticId::Lint::is_force_warn` field;
- adds a `ForceWarning` variant to `Level`.
Benefits:
- The common `Level::Warning` case now has no arguments, replacing
lots of `Warning(None)` occurrences.
- `rustc_session::lint::Level` and `rustc_errors::Level` are more
similar, both having `ForceWarning` and `Warning`.
When writing a no_std binary, you'll be greeted with nonsensical errors
mentioning lang items like eh_personality and start. That's pretty bad
because it makes you think that you need to define them somewhere! But
oh no, now you're getting the `internal_features` lint telling you that
you shouldn't use them! But you need a no_std binary! What now?
No problem! Writing a no_std binary is super easy. Just use panic=abort
and supply your own platform specific entrypoint symbol (like `main`)
and you're good to go. Would be nice if the compiler told you that,
right?
This makes it so that it does do that.
Diagnostic API fixes
Some improvements to diagnostic APIs: improve some naming, use shortcuts in more places, and add a couple of missing methods.
r? `@compiler-errors`
This removes emit_enum_variant and the emit_usize calls that resulted
in. In libcore this eliminates 17% of leb128, taking us from 8964488 to
7383842 leb128's serialized.
100% of the serialized enums during libcore compilation fit into the
smaller tag, and this eliminates hitting the leb128 code for
coding/decoding when we can statically guarantee that's not required.
30% of all leb128 integers serialized in libcore (12981183 total) come
from the usize's removed here.
Avoid silencing relevant follow-up errors
r? `@matthewjasper`
This PR only adds new errors to tests that are already failing and fixes one ICE.
Several tests were changed to not emit new errors. I believe all of them were faulty tests, and not explicitly testing for the code that had new errors.
This lets us avoid the use of `DiagnosticBuilder::into_diagnostic` in
miri, when then means that `DiagnosticBuilder::into_diagnostic` can
become private, being now only used by `stash` and `buffer`.
In #119606 I added them and used a `_mv` suffix, but that wasn't great.
A `with_` prefix has three different existing uses.
- Constructors, e.g. `Vec::with_capacity`.
- Wrappers that provide an environment to execute some code, e.g.
`with_session_globals`.
- Consuming chaining methods, e.g. `Span::with_{lo,hi,ctxt}`.
The third case is exactly what we want, so this commit changes
`DiagnosticBuilder::foo_mv` to `DiagnosticBuilder::with_foo`.
Thanks to @compiler-errors for the suggestion.
We have `span_delayed_bug` and often pass it a `DUMMY_SP`. This commit
adds `delayed_bug`, which matches pairs like `err`/`span_err` and
`warn`/`span_warn`.
- `struct_foo` + `emit` -> `foo`
- `create_foo` + `emit` -> `emit_foo`
I have made recent commits in other PRs that have removed some of these
shortcuts for combinations with few uses, e.g.
`struct_span_err_with_code`. But for the remaining combinations that
have high levels of use, we might as well use them wherever possible.
Because it takes an error code after the span. This avoids the confusing
overlap with the `DiagCtxt::struct_span_err` method, which doesn't take
an error code.
`~const` trait and projection bounds do not imply their non-const counterparts
This PR removes the hack where we install a non-const trait and projection bound for every `const_trait` and `~const` projection bound we have in the AST. It ends up messing up more things than it fixes, see words below.
Fixes#119718
cc `@fmease` `@fee1-dead` `@oli-obk`
r? fee1-dead or one of y'all i don't care
---
My understanding is that this hack was added to support the following code:
```rust
pub trait Owo<X = <Self as Uwu>::T> {}
#[const_trait]
pub trait Uwu: Owo {}
```
Which is concretely lifted from in the `FromResidual` and `Try` traits. Since within the param-env of `trait Uwu`, we only know that `Self: ~const Uwu` and not `Self: Uwu`, the projection `<Self as Uwu>::T` is not satsifyable.
This causes problems such as #119718, since instantiations of `FnDef` types coming from `const fn` really do **only** implement one of `FnOnce` or `const FnOnce`!
---
In the long-term, I believe that such code should really look something more like:
```rust
#[const_trait]
pub trait Owo<X = <Self as ~const Uwu>::T> {}
#[const_trait]
pub trait Uwu: Owo {}
```
... and that we should introduce some sort of `<T as ~const Foo>::Bar` bound syntax, since due to the fact that `~const` bounds can be present in item bounds, e.g.
```rust
#[const_trait] trait Foo { type Bar: ~const Destruct; }
```
It's easy to see that `<T as Foo>::Bar` and `<T as ~const Foo>::Bar` (or `<T as const Foo>::Bar`) can be distinct types with distinct item bounds!
**Admission**: I know I've said before that I don't like `~const` projection syntax, I do at this point believe they're necessary to fully express bounds and types in a maybe-const world.
GNU/Hurd: unconditionally use inline stack probes
LLVM 11 has been unsupported since 45591408b1, so this doesn't need to be conditional on the LLVM version.
cc `@sthibaul`
Remove `-Zdont-buffer-diagnostics`.
It was added in #54232. It seems like it was aimed at NLL development, which is well in the past. Also, it looks like `-Ztreat-err-as-bug` can be used to achieve the same effect. So it doesn't seem necessary.
r? ``@pnkfelix``
Merge dead bb pruning and unreachable bb deduplication.
Both routines share the same basic structure: iterate on all bbs to identify work, and then renumber bbs.
We can do both at once.
unify query canonicalization mode
Exclude from canonicalization only the static lifetimes that appear in the param env because of #118965 . Any other occurrence can be canonicalized safely AFAICT.
r? `@lcnr`
Support async recursive calls (as long as they have indirection)
Before #101692, we stored coroutine witness types directly inside of the coroutine. That means that a coroutine could not contain itself (as a witness field) without creating a cycle in the type representation of the coroutine, which we detected with the `OpaqueTypeExpander`, which is used to detect cycles when expanding opaque types after that are inferred to contain themselves.
After `-Zdrop-tracking-mir` was stabilized, we no longer store these generator witness fields directly, but instead behind a def-id based query. That means there is no technical obstacle in the compiler preventing coroutines from containing themselves per se, other than the fact that for a coroutine to have a non-infinite layout, it must contain itself wrapped in a layer of allocation indirection (like a `Box`).
This means that it should be valid for this code to work:
```
async fn async_fibonacci(i: u32) -> u32 {
if i == 0 || i == 1 {
i
} else {
Box::pin(async_fibonacci(i - 1)).await
+ Box::pin(async_fibonacci(i - 2)).await
}
}
```
Whereas previously, you'd need to coerce the future to `Pin<Box<dyn Future<Output = ...>>` before `await`ing it, to prevent the async's desugared coroutine from containing itself across as await point.
This PR does two things:
1. Only report an error if an opaque expansion cycle is detected *not* through coroutine witness fields.
* Instead, if we find an opaque cycle through coroutine witness fields, we compute the layout of the coroutine. If that results in a cycle error, we report it as a recursive async fn.
4. Reworks the way we report layout errors having to do with coroutines, to make up for the diagnostic regressions introduced by (1.). We actually do even better now, pointing out the call sites of the recursion!
Adding alignment to the cases to test for specific error messages.
Adding alignment to the list of cases to test for specific error message. Covers `>`, `^` and `<`.
Pinging people who chimed in last time ( https://github.com/rust-lang/rust/pull/106805 ): ``@estebank`` , ``@compiler-errors`` and ``@Nilstrieb``
Add -Zuse-sync-unwind
Currently Rust uses async unwind by default, but async unwind will bring non-negligible size overhead. it would be nice to allow users to choose this.
In addition, async unwind currently prevents LLVM from generate compact unwind for MachO, if one wishes to generate compact unwind for MachO, then also needs this flag.
Remove crossbeam-channel
The standard library's std::sync::mpsc basically is a crossbeam channel, and for the use case here will definitely suffice. This drops this dependency from librustc_driver.
Add helper for when we want to know if an item has a host param
r? ````@fmease```` since you're a good reviewer and no good deed goes unpunished
This helper will see far more usages as built-in traits get constified.
coverage: `llvm-cov` expects column numbers to be bytes, not code points
Normally the compiler emits column numbers as a 1-based number of Unicode code points.
But when we embed coverage mappings for `-Cinstrument-coverage`, those mappings will ultimately be read by the `llvm-cov` tool. That tool assumes that column numbers are 1-based numbers of *bytes*, and relies on that assumption when slicing up source code to apply highlighting (in HTML reports, and in text-based reports with colour).
For the very common case of all-ASCII source code, bytes and code points are the same, so the difference isn't noticeable. But for code that contains non-ASCII characters, emitting column numbers as code points will result in `llvm-cov` slicing strings in the wrong places, producing mangled output or fatal errors.
(See https://github.com/taiki-e/cargo-llvm-cov/issues/275 as an example of what can go wrong.)
Improved support of collapse_debuginfo attribute for macros.
Added walk_chain_collapsed function to consider collapse_debuginfo attribute in parent macros in call chain.
Fixed collapse_debuginfo attribute processing for cranelift (there was if/else branches error swap).
cc https://github.com/rust-lang/rust/issues/100758
It was added in #54232. It seems like it was aimed at NLL development,
which is well in the past. Also, it looks like `-Ztreat-err-as-bug` can
be used to achieve the same effect. So it doesn't seem necessary.
Consuming `emit`
This PR makes `DiagnosticBuilder::emit` consuming, i.e. take `self` instead of `&mut self`. This is good because it doesn't make sense to emit a diagnostic twice.
This requires some changes to `DiagnosticBuilder` method changing -- every existing non-consuming chaining method gets a new consuming partner with a `_mv` suffix -- but permits a host of beneficial follow-up changes: more concise code through more chaining, removal of redundant diagnostic construction API methods, and removal of machinery to track the possibility of a diagnostic being emitted multiple times.
r? `@compiler-errors`
They are no longer used, because
`{DiagCtxt,DiagCtxtInner}::emit_diagnostic` are used everywhere instead.
This also means `track_diagnostic` can become consuming.
Currently it's used for two dynamic checks:
- When a diagnostic is emitted, has it been emitted before?
- When a diagnostic is dropped, has it been emitted/cancelled?
The first check is no longer need, because `emit` is consuming, so it's
impossible to emit a `DiagnosticBuilder` twice. The second check is
still needed.
This commit replaces `DiagnosticBuilderState` with a simpler
`Option<Box<Diagnostic>>`, which is enough for the second check:
functions like `emit` and `cancel` can take the `Diagnostic` and then
`drop` can check that the `Diagnostic` was taken.
The `DiagCtxt` reference from `DiagnosticBuilderState` is now stored as
its own field, removing the need for the `dcx` method.
As well as making the code shorter and simpler, the commit removes:
- One (deprecated) `ErrorGuaranteed::unchecked_claim_error_was_emitted`
call.
- Two `FIXME(eddyb)` comments that are no longer relevant.
- The use of a dummy `Diagnostic` in `into_diagnostic`.
Nice!
The existing uses are replaced in one of three ways.
- In a function that also has calls to `emit`, just rearrange the code
so that exactly one of `delay_as_bug` or `emit` is called on every
path.
- In a function returning a `DiagnosticBuilder`, use
`downgrade_to_delayed_bug`. That's good enough because it will get
emitted later anyway.
- In `unclosed_delim_err`, one set of errors is being replaced with
another set, so just cancel the original errors.
The old code was very hard to understand, involving an
`emit_without_consuming` call *and* a `delay_as_bug_without_consuming`
call.
With slight changes both calls can be avoided. Not creating the error
until later is crucial, as is the early return in the `if recovered`
block.
It took me some time to come up with this reworking -- it went through
intermediate states much further from the original code than this final
version -- and it's isn't obvious at a glance that it is equivalent. But
I think it is, and the unchanged test behaviour is good supporting
evidence.
The commit also changes `check_trailing_angle_brackets` to return
`Option<ErrorGuaranteed>`. This provides a stricter proof that it
emitted an error message than asserting `dcx.has_errors().is_some()`,
which would succeed if any error had previously been emitted anywhere.
It's not clear why this was here, because the created error is returned
as a normal error anyway.
Nor is it clear why removing the call works. The change doesn't affect
any tests; `tests/ui/parser/issues/issue-102182-impl-trait-recover.rs`
looks like the only test that could have been affected.
Instead of taking `seq` as a mutable reference,
`maybe_recover_struct_lit_bad_delims` now consumes `seq` on the recovery
path, and returns `seq` unchanged on the non-recovery path. The commit
also combines an `if` and a `match` to merge two identical paths.
Also change `recover_seq_parse_error` so it receives a `PErr` instead of
a `PResult`, because all the call sites now handle the `Ok`/`Err`
distinction themselves.
In this parsing recovery function, we only need to emit the previously
obtained error message and mark `expr` as erroneous in the case where we
actually recover.
This works for most of its call sites. This is nice, because `emit` very
much makes sense as a consuming operation -- indeed,
`DiagnosticBuilderState` exists to ensure no diagnostic is emitted
twice, but it uses runtime checks.
For the small number of call sites where a consuming emit doesn't work,
the commit adds `DiagnosticBuilder::emit_without_consuming`. (This will
be removed in subsequent commits.)
Likewise, `emit_unless` becomes consuming. And `delay_as_bug` becomes
consuming, while `delay_as_bug_without_consuming` is added (which will
also be removed in subsequent commits.)
All this requires significant changes to `DiagnosticBuilder`'s chaining
methods. Currently `DiagnosticBuilder` method chaining uses a
non-consuming `&mut self -> &mut Self` style, which allows chaining to
be used when the chain ends in `emit()`, like so:
```
struct_err(msg).span(span).emit();
```
But it doesn't work when producing a `DiagnosticBuilder` value,
requiring this:
```
let mut err = self.struct_err(msg);
err.span(span);
err
```
This style of chaining won't work with consuming `emit` though. For
that, we need to use to a `self -> Self` style. That also would allow
`DiagnosticBuilder` production to be chained, e.g.:
```
self.struct_err(msg).span(span)
```
However, removing the `&mut self -> &mut Self` style would require that
individual modifications of a `DiagnosticBuilder` go from this:
```
err.span(span);
```
to this:
```
err = err.span(span);
```
There are *many* such places. I have a high tolerance for tedious
refactorings, but even I gave up after a long time trying to convert
them all.
Instead, this commit has it both ways: the existing `&mut self -> Self`
chaining methods are kept, and new `self -> Self` chaining methods are
added, all of which have a `_mv` suffix (short for "move"). Changes to
the existing `forward!` macro lets this happen with very little
additional boilerplate code. I chose to add the suffix to the new
chaining methods rather than the existing ones, because the number of
changes required is much smaller that way.
This doubled chainging is a bit clumsy, but I think it is worthwhile
because it allows a *lot* of good things to subsequently happen. In this
commit, there are many `mut` qualifiers removed in places where
diagnostics are emitted without being modified. In subsequent commits:
- chaining can be used more, making the code more concise;
- more use of chaining also permits the removal of redundant diagnostic
APIs like `struct_err_with_code`, which can be replaced easily with
`struct_err` + `code_mv`;
- `emit_without_diagnostic` can be removed, which simplifies a lot of
machinery, removing the need for `DiagnosticBuilderState`.
macro_rules: Add an expansion-local cache to span marker
Most tokens in a macro body typically have the same syntax context.
So the cache should usually be hit.
This change can either be combined with https://github.com/rust-lang/rust/pull/119689, or serve as its alternative, depending on perf results.
The standard library's std::sync::mpsc basically is a crossbeam channel,
and for the use case here will definitely suffice. This drops this
dependency from librustc_driver.
Unions are not `PointerLike`
I introduced the `PointerLike` trait to enforce `dyn*` coercions only from types that share the same ABI as a pointer. On top of needing to be scalar, they also should not be unions, since CTFE chokes on scalar reads for union types.
Fixes#119695
Impl trait diagnostic tweaks
1. Tweak some names for `impl Trait` being used in the wrong position
2. Remove two helper functions that are no longer needed since RPITIT is stable, and which causes matches to be a bit obtuse.
3. Split and fix the part where the error notes that it's "only allowed in XX"
Fixes#119629
It's incorrect because `CtorSet::split` returns a non-present
constructor into `present` in one specific case: variable-length slices
of an empty type. That's because empty constructors of arity 0 break the
algorithm. This is a tricky corner case that's hard to do cleanly. The
assert wasn't adding much anyway.
Exhaustiveness: remove `Matrix.wildcard_row`
To compute exhaustiveness, we check whether an extra row with a wildcard added at the end of the match expression would be reachable. We used to store an actual such row of patterns in the `Matrix`, but it's a bit redundant since we know it only contains wildcards. It was kept because we used it to get the type of each column (and relevancy). With this PR, we keep track of the types (and relevancy) directly.
This is part of me splitting up https://github.com/rust-lang/rust/pull/119581 for ease of review.
r? `@compiler-errors`
Populate `yield` and `resume` types in MIR body while body is being initialized
I found it weird that we went back and populated these types *after* the body was constructed. Let's just do it all at once.
Stop allowing `rustc::potential_query_instability` on all of
rustc_mir_transform and instead allow it on a case-by-case basis if it
is safe to do so. In this particular crate, all instances were safe to
allow.
rustc_span: More consistent span combination operations
Also add more tests for using `tt` in addition to `ident`, and some other minor tweaks, see individual commits.
This is a part of https://github.com/rust-lang/rust/pull/119412 that doesn't yet add side tables for metavariable spans.
rustc_mir_transform: Make DestinationPropagation stable for queries
By using `FxIndexMap` instead of `FxHashMap`, so that the order of visiting of locals is deterministic.
We also need to bless
`copy_propagation_arg.foo.DestinationPropagation.panic*.diff`. Do not review the diff of the diff. Instead look at the diff files before and after this commit. Both before and after this commit, 3 statements are replaced with nop. It's just that due to change in ordering, different statements are replaced. But the net result is the same. In other words, compare this diff (before fix):
* 090d5eac72/tests/mir-opt/dest-prop/copy_propagation_arg.foo.DestinationPropagation.panic-unwind.diff
With this diff (after fix):
* f603babd63/tests/mir-opt/dest-prop/copy_propagation_arg.foo.DestinationPropagation.panic-unwind.diff
and you can see that both before and after the fix, we replace 3 statements with `nop`s.
I find it _slightly_ surprising that the test this PR affects did not previously fail spuriously due to the indeterminism of `FxHashMap`, but I guess in can be explained with the predictability of small `FxHashMap`s with `usize` (`Local`) keys, or something along those lines.
This should fix [this](https://github.com/rust-lang/rust/pull/119252#discussion_r1436101791) comment, but I wanted to make a separate PR for this fix for a simpler development and review process.
Part of https://github.com/rust-lang/rust/issues/84447 which is E-help-wanted.
r? `@cjgillot` who is reviewer for the highly related PR https://github.com/rust-lang/rust/pull/119252.
rustc_span: Optimize syntax context comparisons
Including comparisons with root context.
- `eq_ctxt` doesn't require retrieving full `SpanData`, or taking the span interner lock twice.
- Checking `SyntaxContext` for "rootness" is cheaper than extracting a full outer `ExpnData` for it and checking *it* for rootness.
The internal lint for `eq_ctxt` is also tweaked to detect `a.ctxt() != b.ctxt()` in addition to `a.ctxt() == b.ctxt()`.
Avoid specialization in the metadata serialization code
With the exception of a perf-only specialization for byte slices and byte vectors.
This uses the same trick of introducing a new trait and having the Encodable and Decodable derives add a bound to it as used for TyEncoder/TyDecoder. The new code is clearer about which encoder/decoder uses which impl and it reduces the dependency of rustc on specialization, making it easier to remove support for specialization entirely or turn it into a construct that is only allowed for perf optimizations if we decide to do this.
Rollup of 9 pull requests
Successful merges:
- #119208 (coverage: Hoist some complex code out of the main span refinement loop)
- #119216 (Use diagnostic namespace in stdlib)
- #119414 (bootstrap: Move -Clto= setting from Rustc::run to rustc_cargo)
- #119420 (Handle ForeignItem as TAIT scope.)
- #119468 (rustdoc-search: tighter encoding for f index)
- #119628 (remove duplicate test)
- #119638 (fix cyle error when suggesting to use associated function instead of constructor)
- #119640 (library: Fix warnings in rtstartup)
- #119642 (library: Fix a symlink test failing on Windows)
r? `@ghost`
`@rustbot` modify labels: rollup
fix cyle error when suggesting to use associated function instead of constructor
Fixes https://github.com/rust-lang/rust/issues/119625.
The first commit fixes the infinite recursion and makes the cycle error actually show up. We do this by making the `Display` for `ty::Instance` impl respect `with_no_queries` so that it can be used in query descriptions.
The second commit fixes the cycle error `resolver_for_lowering` -> `normalize` -> `resolve_instance` (for evaluating const) -> `lang_items` (for `drop_in_place`) -> `resolver_for_lowering` (for collecting lang items). We do this by simply skipping the suggestion when encountering an unnormalized type.
Use diagnostic namespace in stdlib
This required a minor fix to have the diagnostics shown in third party crates when the `diagnostic_namespace` feature is not enabled. See 5d63f5d8d1 for details. I've opted for having a single PR for both changes as it's really not that much code. If it is required it should be easy to split up the change into several PR's.
r? `@compiler-errors`
coverage: Hoist some complex code out of the main span refinement loop
The span refinement loop in `spans.rs` takes the spans that have been extracted from MIR, and modifies them to produce more helpful output in coverage reports.
It is also one of the most complicated pieces of code in the coverage instrumentor. It has an abundance of moving pieces that make it difficult to understand, and most attempts to modify it end up accidentally changing its behaviour in unacceptable ways.
This PR nevertheless tries to make a dent in it by hoisting two pieces of special-case logic out of the main loop, and into separate preprocessing passes. Coverage tests show that the resulting mappings are *almost* identical, with all known differences being unimportant.
This should hopefully unlock further simplifications to the refinement loop, since it now has fewer edge cases to worry about.
Exhaustiveness: Statically enforce revealing of opaques
In https://github.com/rust-lang/rust/pull/116821 it was decided that exhaustiveness should operate on the hidden type of an opaque type when relevant. This PR makes sure we consistently reveal opaques within exhaustiveness. This makes it possible to remove `reveal_opaque_ty` from the `TypeCx` trait which was an unfortunate implementation detail.
r? `@compiler-errors`
Rollup of 8 pull requests
Successful merges:
- #119151 (Hide foreign `#[doc(hidden)]` paths in import suggestions)
- #119350 (Imply outlives-bounds on lazy type aliases)
- #119354 (Make `negative_bounds` internal & fix some of its issues)
- #119506 (Use `resolutions(()).effective_visiblities` to avoid cycle errors in `report_object_error`)
- #119554 (Fix scoping for let chains in match guards)
- #119563 (Check yield terminator's resume type in borrowck)
- #119589 (cstore: Remove unnecessary locking from `CrateMetadata`)
- #119622 (never patterns: Document behavior of never patterns with macros-by-example)
r? `@ghost`
`@rustbot` modify labels: rollup
By using FxIndexMap instead of FxHashMap, so that the order of visiting
of locals is deterministic.
We also need to bless
copy_propagation_arg.foo.DestinationPropagation.panic*.diff. Do not
review the diff of the diff. Instead look at the diff file before and
after this commit. Both before and after this commit, 3 statements are
replaced with nop. It's just that due to change in ordering, different
statements are replaced. But the net result is the same.
cstore: Remove unnecessary locking from `CrateMetadata`
Locks and atomics in `CrateMetadata` fields were necessary before https://github.com/rust-lang/rust/pull/107765 when `CStore` was cloneable, but now they are not necessary and can be removed after restructuring the code a bit to please borrow checker.
All remaining locked fields in `CrateMetadata` are lazily populated caches.
Check yield terminator's resume type in borrowck
In borrowck, we didn't check that the lifetimes of the `TerminatorKind::Yield`'s `resume_place` were actually compatible with the coroutine's signature. That means that the lifetimes were totally going unchecked. Whoops!
This PR implements this checking.
Fixes#119564
r? types
Fix scoping for let chains in match guards
If let guards were previously represented as a different type of guard in HIR and THIR. This meant that let chains in match guards were not handled correctly because they were treated exactly like normal guards.
- Remove `hir::Guard` and `thir::Guard`.
- Make the scoping different between normal guards and if let guards also check for let chains.
closes#118593
Use `resolutions(()).effective_visiblities` to avoid cycle errors in `report_object_error`
Inside of `report_object_error`, using the `effective_visibilities` query causes cycles since it calls `type_of`, which itself may call `typeck`, which may end up reporting its own object-safety errors.
Fixes#119346Fixes#119502
Hide foreign `#[doc(hidden)]` paths in import suggestions
Stops the compiler from suggesting to import foreign `#[doc(hidden)]` paths.
```@rustbot``` label A-suggestion-diagnostics
Replace a number of FxHashMaps/Sets with stable-iteration-order alternatives
This PR replaces almost all of the remaining `FxHashMap`s in query results with either `FxIndexMap` or `UnordMap`. The only case that is missing is the `EffectiveVisibilities` struct which turned out to not be straightforward to transform. Once that is done too, we can remove the `HashStable` implementation from `HashMap`.
The first commit adds the `StableCompare` trait which is a companion trait to `StableOrd`. Some types like `Symbol` can be compared in a cross-session stable way, but their `Ord` implementation is not stable. In such cases, a `StableCompare` implementation can be provided to offer a lightweight way for stable sorting. The more heavyweight option is to sort via `ToStableHashKey`, but then sorting needs to have access to a stable hashing context and `ToStableHashKey` can also be expensive as in the case of `Symbol` where it has to allocate a `String`.
The rest of the commits are rather mechanical and don't overlap, so they are best reviewed individually.
Part of [MCP 533](https://github.com/rust-lang/compiler-team/issues/533).
In the past it did create a fresh expansion, but now, after surviving a number of refactorings, it does not.
Now it's just a thin wrapper around `apply_mark`.
Migrate memory overlap check from validator to lint
The check attempts to identify potential undefined behaviour, rather
than whether MIR is well-formed. It belongs in the lint not validator.
Follow up to changes from #119077.
Remove `-Zreport-delayed-bugs`.
It's not used within the repository in any way (e.g. in tests), and doesn't seem useful.
It was added in #52568.
r? ````@oli-obk````
Remove `-Zdump-mir-spanview`
The `-Zdump-mir-spanview` flag was added back in #76074, as a development/debugging aid for the initial work on what would eventually become `-Cinstrument-coverage`. It causes the compiler to emit an HTML file containing a function's source code, with various spans highlighted based on the contents of MIR.
When the suggestion was made to [triage and remove unnecessary `-Z` flags (Zulip)](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/.60-Z.60.20option.20triage), I noted that this flag could potentially be worth removing, but I wanted to keep it around to see whether I found it useful for my own coverage work.
But when I actually tried to use it, I ran into various issues (e.g. it crashes on `tests/coverage/closure.rs`). If I can't trust it to work properly without a full overhaul, then instead of diving down a rabbit hole of trying to fix arcane span-handling bugs, it seems better to just remove this obscure old code entirely.
---
````@rustbot```` label +A-code-coverage
Tweak suggestions for bare trait used as a type
```
error[E0782]: trait objects must include the `dyn` keyword
--> $DIR/not-on-bare-trait-2021.rs:11:11
|
LL | fn bar(x: Foo) -> Foo {
| ^^^
|
help: use a generic type parameter, constrained by the trait `Foo`
|
LL | fn bar<T: Foo>(x: T) -> Foo {
| ++++++++ ~
help: you can also use `impl Foo`, but users won't be able to specify the type paramer when calling the `fn`, having to rely exclusively on type inference
|
LL | fn bar(x: impl Foo) -> Foo {
| ++++
help: alternatively, use a trait object to accept any type that implements `Foo`, accessing its methods at runtime using dynamic dispatch
|
LL | fn bar(x: &dyn Foo) -> Foo {
| ++++
error[E0782]: trait objects must include the `dyn` keyword
--> $DIR/not-on-bare-trait-2021.rs:11:19
|
LL | fn bar(x: Foo) -> Foo {
| ^^^
|
help: use `impl Foo` to return an opaque type, as long as you return a single underlying type
|
LL | fn bar(x: Foo) -> impl Foo {
| ++++
help: alternatively, you can return an owned trait object
|
LL | fn bar(x: Foo) -> Box<dyn Foo> {
| +++++++ +
```
Fix#119525:
```
error[E0038]: the trait `Ord` cannot be made into an object
--> $DIR/bare-trait-dont-suggest-dyn.rs:3:33
|
LL | fn ord_prefer_dot(s: String) -> Ord {
| ^^^ `Ord` cannot be made into an object
|
note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $SRC_DIR/core/src/cmp.rs:LL:COL
|
= note: the trait cannot be made into an object because it uses `Self` as a type parameter
::: $SRC_DIR/core/src/cmp.rs:LL:COL
|
= note: the trait cannot be made into an object because it uses `Self` as a type parameter
help: consider using an opaque type instead
|
LL | fn ord_prefer_dot(s: String) -> impl Ord {
| ++++
```
Separate immediate and in-memory ScalarPair representation
Currently, we assume that ScalarPair is always represented using a two-element struct, both as an immediate value and when stored in memory.
This currently works fairly well, but runs into problems with https://github.com/rust-lang/rust/pull/116672, where a ScalarPair involving an i128 type can no longer be represented as a two-element struct in memory. For example, the tuple `(i32, i128)` needs to be represented in-memory as `{ i32, [3 x i32], i128 }` to satisfy alignment requirements. Using `{ i32, i128 }` instead will result in the second element being stored at the wrong offset (prior to LLVM 18).
Resolve this issue by no longer requiring that the immediate and in-memory type for ScalarPair are the same. The in-memory type will now look the same as for normal struct types (and will include padding filler and similar), while the immediate type stays a simple two-element struct type. This also means that booleans in immediate ScalarPair are now represented as i1 rather than i8, just like we do everywhere else.
The core change here is to llvm_type (which now treats ScalarPair as a normal struct) and immediate_llvm_type (which returns the two-element struct that llvm_type used to produce). The rest is fixing things up to no longer assume these are the same. In particular, this switches places that try to get pointers to the ScalarPair elements to use byte-geps instead of struct-geps.
nightly feature
(Using this attribute still requires a nightly feature, this just
enables that this feature does not need to be enabled on the child crate
as well)
Match guards with an if let guard or an if let chain guard should have a
temporary scope of the whole arm. This is to allow ref bindings to
temporaries to borrow check.
Currently for these two errors we go to the effort of switching to a
standard JSON emitter, for no obvious reason, and unlike any other
errors. This behaviour was added for `pretty-json` in #45737, and then
`human-annotate-rs` copied it some time later when it was added.
This commit changes things to just using the requested emitter, which is
simpler and consistent with other errors.
Old output:
```
$ rustc --error-format pretty-json
{"$message_type":"diagnostic","message":"`--error-format=pretty-json` is unstable","code":null,"level":"error","spans":[],"children":[],"rendered":"error: `--error-format=pretty-json` is unstable\n\n"}
$ rustc --error-format human-annotate-rs
{"$message_type":"diagnostic","message":"`--error-format=human-annotate-rs` is unstable","code":null,"level":"error","spans":[],"children":[],"rendered":"error: `--error-format=human-annotate-rs` is unstable\n\n"}
```
New output:
```
$ rustc --error-format pretty-json
{
"$message_type": "diagnostic",
"message": "`--error-format=pretty-json` is unstable",
"code": null,
"level": "error",
"spans": [],
"children": [],
"rendered": "error: `--error-format=pretty-json` is unstable\n\n"
}
$ rustc --error-format human-annotate-rs
error: `--error-format=human-annotate-rs` is unstable
```
This draws a clear distinction between the fields/methods that are needed by
initial span extraction and preprocessing, and those that are needed by the
main "refinement" loop.
Reorder check_item_type diagnostics so they occur next to the corresponding `check_well_formed` diagnostics
The first commit is just a cleanup.
The second commit moves most checks from `check_mod_item_types` into `check_well_formed`, invoking the checks in lockstep per-item instead of iterating over all items twice.
