Rework explanation of CLI lint level flags
I think the previous wording as either wrong or confusing. I would consider the CLI flags at a *lower* ranking, since source attributes are able to override the CLI flag.
Add documentation note about signed overflow direction
In https://github.com/rust-lang/rust/issues/151989#issuecomment-3845282666 I noticed that signed overflow direction can be determined by returned wrapped value. It is not very obvious (especially, assuming additional `carry: bool` summand), but it is important if we want to add new leading (signed) limb to big integer in this case.
Examples for small summands `x, y: i8` with result extension:
| x | y | overflow | result as (u8, i8) |
| ---- | ---- | -------- | ------------------ |
| -1 | -128 | true | (127, -1) |
| 0 | -1 | false | (255, -1) |
| 2 | 2 | false | (4, 0) |
| 127 | 1 | true | (128, 0) |
Here is general proof.
1. Set $s=2^{N-1}$ and let's say `iN::carrying_add(x, y, c)` returns `(result, true)` then
$$
\mathrm{result}=\begin{cases}
x + y + c + 2s,& x + y + c \le -s-1,\\
x+y+c-2s,& x+y+c\ge s.
\end{cases}
$$
First case is overflowing below `iN::MIN` and we have
$$
\mathrm{result}\ge -s-s+0+2s =0;\qquad
\mathrm{result}=x + y + c + 2s\le -s-1+2s = s - 1,
$$
so we obtain $[0; s-1]$ which is exactly range of non-negative `iN`.
Second case is overflowing above `iN::MAX` and
$$
\mathrm{result}=x+y+c-2s\ge s-2s =-s;\qquad
\mathrm{result}\le s-1 + s-1+1-2s = -1,
$$
that is, $[-s,-1]$ which is exactly range of negative `iN`.
2. Now suppose that `iN::borrowing_sub(x,y,b)` returns `(result, true)` then
$$
\mathrm{result}=\begin{cases}
x - y - b + 2s,& x - y - b \le -s-1,\\
x - y - b - 2s,& x - y - b\ge s.
\end{cases}
$$
First case is overflowing below `iN::MIN` and we have
$$
\mathrm{result}\ge -s-(s-1)-1+2s =0;\qquad
\mathrm{result}=x - y - b + 2s\le -s-1+2s = s - 1.
$$
Second case is overflowing above `iN::MAX` and
$$
\mathrm{result}=x-y-b-2s\ge s-2s =-s;\qquad
\mathrm{result}\le s-1 - (-s) - 0 - 2s = -1.
$$
Fix invalid `mut T` suggestion for `&mut T` in missing lifetime error
close: rust-lang/rust#150077
When suggesting to return an owned value instead of a borrowed one, the diagnostic was only removing `&` instead of `&mut `, resulting in invalid syntax like `mut T`. This PR fixes the span calculation to properly cover the entire `&mut ` prefix.
remove the explicit error for old `rental` versions
This was converted to a hard error 20 months ago (in rust-lang/rust#125596). This seems like enough time for anyone still using it to notice, so remove the note entirely now.
In comparison, the explicit note for the more impactful `time` breakage was already removed after 6 months (rust-lang/rust#129343).
Closesrust-lang/rust#73933.
Closesrust-lang/rust#83125.
r? @petrochenkov
Rename dep node "fingerprints" to distinguish key and value hashes
In the query system's dependency graph, each node is associated with two *fingerprints*: one that is typically a hash of the query key, and one that is typically a hash of the query's return value when called with that key.
Unfortunately, many identifiers and comments fail to clearly distinguish between these two kinds of fingerprint, which have very different roles in dependency tracking. This is a frequent source of confusion.
This PR therefore tries to establish a clear distinction between:
- **Key fingerprints** that help to uniquely identify a node (along with its `DepKind`), and are typically a hash of the query key
- **Value fingerprints** that help to determine whether a node can be marked green (despite having red dependencies), and are typically a hash of the query value
There should be no change to compiler behaviour.
r? nnethercote (or compiler)
compiler: Don't mark `SingleUseConsts` MIR pass as "required for soundness"
I don't think this MIR pass is required for soundness. The reasons are:
* Something like it was not enabled by default before PR rust-lang/rust#107404 which was the precursor to `SingleUseConsts` (see rust-lang/rust#125910 for the switch).
* By following the advice from https://github.com/rust-lang/rust/pull/128657#discussion_r1705114015 we can conclude it is not required for soundness since it has only ever run on MIR opt level > 0.
* Its [`MirPass::can_be_overridden()`](0ee7d96253/compiler/rustc_mir_transform/src/pass_manager.rs (L98-L102)) is unchanged and thus returns `true`, indicating that it is not a required MIR pass.
* PR CI pass in rust-lang/rust#151426 which stops enabling it by default in non-optimized builds.
As shown in the updated test `tests/mir-opt/optimize_none.rs`, `#[optimize(none)]` functions become even less optimized, as expected and desired.
Unblocks https://github.com/rust-lang/rust/pull/151426.
tail calls: fix copying non-scalar arguments to callee
Alternative to https://github.com/rust-lang/rust/pull/144933: when invoking a tail call with a non-scalar argument, we need to delay freeing the caller's local variables until after the callee is initialized, so that we can copy things from the caller to the callee.
Fixes https://github.com/rust-lang/rust/issues/144820... but as the FIXMEs in the code show, it's not clear to me whether these are the right semantics.
r? @WaffleLapkin
Unify wording of resolve error
Remove "failed to resolve" from the main error message and use the same format we use in other resolution errors "cannot find `name`":
```
error[E0433]: cannot find `nonexistent` in `existent`
--> $DIR/custom_attr_multisegment_error.rs:5:13
|
LL | #[existent::nonexistent]
| ^^^^^^^^^^^ could not find `nonexistent` in `existent`
```
The intent behind this is to end up with all resolve errors eventually be on the form of
```
error[ECODE]: cannot find `{NAME}` in {SCOPE}
--> $DIR/file.rs:5:13
|
LL | #[existent::nonexistent]
| ^^^^^^^^^^^ {SPECIFIC LABEL}
```
A category of errors that is interest are those that involve keywords. For example:
```
error[E0433]: cannot find `Self` in this scope
--> $DIR/issue-97194.rs:2:35
|
LL | fn bget(&self, index: [usize; Self::DIM]) -> bool {
| ^^^^ `Self` is only available in impls, traits, and type definitions
```
and
```
error[E0433]: cannot find `super` in this scope
--> $DIR/keyword-super.rs:2:9
|
LL | let super: isize;
| ^^^^^ there are too many leading `super` keywords
```
For these the label provides the actual help, while the message is less informative beyond telling you "couldn't find `name`".
This is an off-shoot of https://github.com/rust-lang/rust/pull/126810 and https://github.com/rust-lang/rust/pull/128086, a subset of the intended changes there with review comments applied.
r? @petrochenkov
Support JSON target specs in bootstrap
JSON target specs were destabilized in https://github.com/rust-lang/rust/pull/150151 and https://github.com/rust-lang/rust/pull/151534. However, this broke trying to build rustc itself with a JSON target spec. This is because in a few places bootstrap is manually calling `rustc` without the ability for the user to provide additional flags (primarily, `-Zunstable-options` to enable JSON targets).
There's a few different ways to fix this. One would be to change these calls to `rustc` to include flags provided by the user (such as `RUSTFLAGS_NOT_BOOTSTRAP`). Just to keep things simple, this PR proposes to just unconditionally pass `-Zunstable-options`.
Another consideration here is how maintainable this is. A possible improvement here would be to have a function somewhere (BootstrapCommand, TargetSelection, free function) that would handle appropriately adding the `--target` flag. For example, that's what cargo does in [`CompileKind::add_target_arg`](592058c7ce/src/cargo/core/compiler/compile_kind.rs (L144-L154)).
I have only tested building the compiler and a few tools like rustdoc. I have not tested doing things like building other tools, running tests, etc.
This would be much easier if there was a Docker image for testing the use case of building rustc with a custom target spec (and even better if that ran in CI).
After the next beta branch, using target JSON specs will become more cumbersome because target specs with the `.json` extension will now require passing `-Zjson-target-spec` (from
https://github.com/rust-lang/cargo/pull/16557). This does not affect target specs without the `.json` extension (such as those from RUST_TARGET_PATH). From my testing, it should be sufficient to pass `CARGOFLAGS_NOT_BOOTSTRAP="-Zjson-target-spec"`. I think that should be fine, since this is not a particularly common use case AFAIK. We could extend bootstrap to auto-detect if the target is a file path, and pass `-Zjson-target-spec` appropriately. I tried something similar in f0bdd35483, which could be adapted if desired.
It would be nice if all of this is documented somewhere. https://rustc-dev-guide.rust-lang.org/building/new-target.html does not really say how to build the compiler with a custom json target.
Fixes https://github.com/rust-lang/rust/issues/151729
Remove "failed to resolve" and use the same format we use in other resolution errors "cannot find `name`".
```
error[E0433]: cannot find `nonexistent` in `existent`
--> $DIR/custom_attr_multisegment_error.rs:5:13
|
LL | #[existent::nonexistent]
| ^^^^^^^^^^^ could not find `nonexistent` in `existent`
```
Improve `VaList` stdlib docs
tracking issue: https://github.com/rust-lang/rust/issues/44930
Some improvements to the `VaList` documentation, at least adding an example. We should link to the reference for c-variadic functions once stable. I've tried to call out explicitly that the type is meant for sending over the FFI boundary.
r? workingjubilee
cc @tgross35
remove `#![allow(stable_features)]` from most tests
The only remaining usages are tests that specifically deal with feature gates.
This also deletes the very weird `#![feature(issue_5723_bootstrap)]`, a 13 year old "temporary fix" (rust-lang/rust#5723).
Remove `QueryCtxt` and trait `HasDepContext`
- Follow-up to https://github.com/rust-lang/rust/pull/152636.
- Potentially waiting on https://github.com/rust-lang/rust/pull/152703 to reduce conflicts.
---
With the `QueryContext` trait removed, wrapper struct `QueryCtxt` no longer serves a purpose and can be replaced with `TyCtxt` everywhere.
After that, the only obstacle to removing trait `HasDepContext` is `DepGraph::with_task`, which uses the trait to allow passing both a `TyCtxt` and a query vtable through the context argument. But we can achieve the same result by passing the vtable through the other argument instead, in a tuple alongside the query key.
r? nnethercote
Install LLVM DLL in the right place on Windows
Continuation of https://github.com/rust-lang/rust/pull/151795 towards https://github.com/rust-lang/rust/issues/151774.
Unlike other systems, Windows requires runtime libraries to be present in `PATH` or right next to the binary.
So, we copy the library next to the binary as the easier solution.
Tested building `rust-openssl` in debug and release modes, but the difference is within noise margin.
Revert "Fix an ICE in the vtable iteration for a trait reference"
The ICE fix appears to be unsound, causing a miscompilation involving `dyn Trait` and `async {}` which induces segfaults in safe Rust code. As the patch only hid an ICE, it does not seem worth the risk.
This addresses the problem in rust-lang/rust#152735 but it may still merit team discussion even if this PR is merged.
This reverts commit 8afd63610b, reversing changes made to 19122c03c7.
This struct was only wrapping `TyCtxt` in order to implement traits that
were removed by RUST-152636.
This commit also slightly simplifies the signature of `execute_job_incr`, by
having it call `tcx.dep_graph.data()` internally.
Because:
* Something like it did not exist before PR 107404
* That it is not run our mir-opt-level 0 indicates that it is not
required for soundness
* Its `MirPass::can_be_overridden()` is unchanged and thus returns true,
indicating that it is not a required MIR pass.
* No test fails in PR 151426 that stops enabling by default in non-optimized builds
As can be seen from the updated test `tests/mir-opt/optimize_none.rs`,
this means that `#[optimize(none)]` functions become even less
optimized. As expected and as desired.
Suppress unstable-trait notes under `-Zforce-unstable-if-unmarked`
- Fixes https://github.com/rust-lang/rust/issues/152692.
---
https://github.com/rust-lang/rust/pull/151036 adds extra diagnostic text (“the nightly-only, unstable trait”) to note when a not-implemented trait is unstable.
However, that extra text is usually unhelpful when building a crate graph with `-Zforce-unstable-if-unmarked` (such as the compiler or stdlib), because *any* trait not explicitly marked stable will be treated as unstable.
(For typical compiler contributors using the stage0 compiler, this fix won't take effect until the next bootstrap beta bump.)
Fix mis-constructed `file_span` when generating scraped examples
Fixesrust-lang/rust#152601. Seemingly relative with rust-lang/rust#147399 but I could not reproduce the original ICE.
This PR removes the `file_span` logic from scraped example generation. The original implementation did not read or write items using `file_span`; it only used it to locate a source file, `context.href_from_span`. However, the span was validated against the wrong file, which could trigger ICEs on inputs such as multibyte characters due to an incorrectly constructed span. Since scraped examples do not use the span and the `url` is already given, the safest and simplest fix is to remove it.
Tested against the crate and MCVE documented in the original issue.
P.S. there seems to be some bug when rendering call sites, but since fixing mis-behavior is a change rather than a bug-fix that would be implemented in another PR.
Avoid ICE in From/TryFrom diagnostic under -Znext-solver
Fixesrust-lang/rust#152518.
Under `-Znext-solver=globally`, `trait_ref.args` may contain fewer
elements than expected. The diagnostic logic in
`fulfillment_errors.rs` assumed at least two elements and
unconditionally called `type_at(1)`, which could lead to an
index out-of-bounds panic during error reporting.
This change adds a defensive check before accessing the second
argument to avoid the ICE. A UI regression test has been added.
