Fix representation when printing abstract consts
Previously, when printing a const generic expr, it would only display it as `{{const expr}}`. This allows for a more legible representation when printing these out.
I also zipped the types with their constants for abstract consts that contain function calls when using type annotations, eg: `foo(S: usize, true: bool) -> usize` insteaad of `foo(S, true): fn(usize, bool) -> usize` for conciseness.
Remove some only- clauses from mir-opt tests
Derived from https://github.com/rust-lang/rust/pull/122295
Many of these tests were originally codegen tests, and MIR is more trivially portable than LLVM IR. We simply don't need to restrict the platform in most cases.
r? Nadrieril
There are many cases where, due to codegen or a massively unruly codebase,
a deeply nested call(call(call(call(call(call(call(call(call(f())))))))))
can happen. This is a spot where it would be good to grow our stack, so that
we can survive to tell the programmer their code is dubiously written.
For ref pattern in func param, the mutability suggestion has to apply to the binding.
For example: `fn foo(&x: &i32)` -> `fn foo(&(mut x): &i32)`
fixes#122415
clean up `Sized` checking
This PR cleans up `sized_constraint` and related functions to make them simpler and faster. This should not make more or less code compile, but it can change error output in some rare cases.
## enums and unions are `Sized`, even if they are not WF
The previous code has some special handling for enums, which made them sized if and only if the last field of each variant is sized. For example given this definition (which is not WF)
```rust
enum E<T1: ?Sized, T2: ?Sized, U1: ?Sized, U2: ?Sized> {
A(T1, T2),
B(U1, U2),
}
```
the enum was sized if and only if `T2` and `U2` are sized, while `T1` and `T2` were ignored for `Sized` checking. After this PR this enum will always be sized.
Unsized enums are not a thing in Rust and removing this special case allows us to return an `Option<Ty>` from `sized_constraint`, rather than a `List<Ty>`.
Similarly, the old code made an union defined like this
```rust
union Union<T: ?Sized, U: ?Sized> {
head: T,
tail: U,
}
```
sized if and only if `U` is sized, completely ignoring `T`. This just makes no sense at all and now this union is always sized.
## apply the "perf hack" to all (non-error) types, instead of just type parameters
This "perf hack" skips evaluating `sized_constraint(adt): Sized` if `sized_constraint(adt): Sized` exactly matches a predicate defined on `adt`, for example:
```rust
// `Foo<T>: Sized` iff `T: Sized`, but we know `T: Sized` from a predicate of `Foo`
struct Foo<T /*: Sized */>(T);
```
Previously this was only applied to type parameters and now it is applied to every type. This means that for example this type is now always sized:
```rust
// Note that this definition is WF, but the type `S<T>` not WF in the global/empty ParamEnv
struct S<T>([T]) where [T]: Sized;
```
I don't anticipate this to affect compile time of any real-world program, but it makes the code a bit nicer and it also makes error messages a bit more consistent if someone does write such a cursed type.
## tuples are sized if the last type is sized
The old solver already has this behavior and this PR also implements it for the new solver and `is_trivially_sized`. This makes it so that tuples work more like a struct defined like this:
```rust
struct TupleN<T1, T2, /* ... */ Tn: ?Sized>(T1, T2, /* ... */ Tn);
```
This might improve the compile time of programs with large tuples a little, but is mostly also a consistency fix.
## `is_trivially_sized` for more types
This function is used post-typeck code (borrowck, const eval, codegen) to skip evaluating `T: Sized` in some cases. It will now return `true` in more cases, most notably `UnsafeCell<T>` and `ManuallyDrop<T>` where `T.is_trivially_sized`.
I'm anticipating that this change will improve compile time for some real world programs.
CFI: Break tests into smaller files
Break type metadata identifiers tests into smaller set of tests/files, and move CFI (and KCFI) codegen tests to a cfi (and kcfi) subdirectory,
Stabilize associated type bounds (RFC 2289)
This PR stabilizes associated type bounds, which were laid out in [RFC 2289]. This gives us a shorthand to express nested type bounds that would otherwise need to be expressed with nested `impl Trait` or broken into several `where` clauses.
### What are we stabilizing?
We're stabilizing the associated item bounds syntax, which allows us to put bounds in associated type position within other bounds, i.e. `T: Trait<Assoc: Bounds...>`. See [RFC 2289] for motivation.
In all position, the associated type bound syntax expands into a set of two (or more) bounds, and never anything else (see "How does this differ[...]" section for more info).
Associated type bounds are stabilized in four positions:
* **`where` clauses (and APIT)** - This is equivalent to breaking up the bound into two (or more) `where` clauses. For example, `where T: Trait<Assoc: Bound>` is equivalent to `where T: Trait, <T as Trait>::Assoc: Bound`.
* **Supertraits** - Similar to above, `trait CopyIterator: Iterator<Item: Copy> {}`. This is almost equivalent to breaking up the bound into two (or more) `where` clauses; however, the bound on the associated item is implied whenever the trait is used. See #112573/#112629.
* **Associated type item bounds** - This allows constraining the *nested* rigid projections that are associated with a trait's associated types. e.g. `trait Trait { type Assoc: Trait2<Assoc2: Copy>; }`.
* **opaque item bounds (RPIT, TAIT)** - This allows constraining associated types that are associated with the opaque without having to *name* the opaque. For example, `impl Iterator<Item: Copy>` defines an iterator whose item is `Copy` without having to actually name that item bound.
The latter three are not expressible in surface Rust (though for associated type item bounds, this will change in #120752, which I don't believe should block this PR), so this does represent a slight expansion of what can be expressed in trait bounds.
### How does this differ from the RFC?
Compared to the RFC, the current implementation *always* desugars associated type bounds to sets of `ty::Clause`s internally. Specifically, it does *not* introduce a position-dependent desugaring as laid out in [RFC 2289], and in particular:
* It does *not* desugar to anonymous associated items in associated type item bounds.
* It does *not* desugar to nested RPITs in RPIT bounds, nor nested TAITs in TAIT bounds.
This position-dependent desugaring laid out in the RFC existed simply to side-step limitations of the trait solver, which have mostly been fixed in #120584. The desugaring laid out in the RFC also added unnecessary complication to the design of the feature, and introduces its own limitations to, for example:
* Conditionally lowering to nested `impl Trait` in certain positions such as RPIT and TAIT means that we inherit the limitations of RPIT/TAIT, namely lack of support for higher-ranked opaque inference. See this code example: https://github.com/rust-lang/rust/pull/120752#issuecomment-1979412531.
* Introducing anonymous associated types makes traits no longer object safe, since anonymous associated types are not nameable, and all associated types must be named in `dyn` types.
This last point motivates why this PR is *not* stabilizing support for associated type bounds in `dyn` types, e.g, `dyn Assoc<Item: Bound>`. Why? Because `dyn` types need to have *concrete* types for all associated items, this would necessitate a distinct lowering for associated type bounds, which seems both complicated and unnecessary compared to just requiring the user to write `impl Trait` themselves. See #120719.
### Implementation history:
Limited to the significant behavioral changes and fixes and relevant PRs, ping me if I left something out--
* #57428
* #108063
* #110512
* #112629
* #120719
* #120584Closes#52662
[RFC 2289]: https://rust-lang.github.io/rfcs/2289-associated-type-bounds.html
`NormalizesTo`: return nested goals to caller
Fixes the regression of `paperclip-core`. see https://hackmd.io/IsVAafiOTAaPIFcUxRJufw for more details.
r? ```@compiler-errors```
Provide structured suggestion for `#![feature(foo)]`
```
error: `S2<'_>` is forbidden as the type of a const generic parameter
--> $DIR/lifetime-in-const-param.rs:5:23
|
LL | struct S<'a, const N: S2>(&'a ());
| ^^
|
= note: the only supported types are integers, `bool` and `char`
help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
|
LL + #![feature(adt_const_params)]
|
```
Fix#55941.
never patterns: suggest `!` patterns on non-exhaustive matches
When a match is non-exhaustive we now suggest never patterns whenever it makes sense.
r? ``@compiler-errors``
Reject overly generic assoc const binding types
Split off from #119385 to make #119385 easier to review.
---
In the *instantiated* type of assoc const bindings
1. reject **early-bound generic params**
* Provide a rich error message instead of ICE'ing ([#108271](https://github.com/rust-lang/rust/issues/108271)).
* This is a temporary and semi-artificial restriction until the arrival of *generic const generics*.
* It's quite possible that rustc could already perfectly support this subset of generic const generics if we just removed some checks (some `.no_bound_vars().expect(…)`) but even if that was the case, I'd rather gate it behind a new feature flag. Reporting an error instead of ICE'ing is a good first step towards an eventual feature gate error.
2. reject **escaping late-bound generic params**
* They lead to ICEs before & I'm pretty sure that they remain incorrect even in a world with *generic const generics*
---
Together with #118668 & #119385, this supersedes #118360.
Fixes#108271.
```
error: `S2<'_>` is forbidden as the type of a const generic parameter
--> $DIR/lifetime-in-const-param.rs:5:23
|
LL | struct S<'a, const N: S2>(&'a ());
| ^^
|
= note: the only supported types are integers, `bool` and `char`
help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
|
LL + #![feature(adt_const_params)]
|
```
Fix#55941.
A bit of an inelegant fix but given that the error is created only
after call to `const_eval_poly()` and that the calling function
cannot propagate the error anywhere else, the error has to be
explicitly handled inside `mono_item.rs`.
Do not eat nested expressions' results in `MayContainYieldPoint` format args visitor
#121563 unintentionally changed the `MayContainYieldPoint` format args visitor behavior, now missing yield points in nested expressions, as seen in #122674.
The walk can find a yield point in an expression but it was ignored.
r? ``@petrochenkov`` as the reviewer of #121563
cc ``@Jarcho`` as the author
Fixes#122674.
We're in the 1.77 release week. #121563 will land on 1.78 but beta is still 1.77.9: this PR will likely need to be backported soon after beta is cut.
Update the minimum external LLVM to 17
With this change, we'll have stable support for LLVM 17 and 18.
For reference, the previous increase to LLVM 16 was #117947.
Move `option_env!` and `env!` tests to the `env-macro` directory
This PR moves the `option_env!` tests to there own directory (`extoption_env`), matching the naming convention used by the tests for `env!` (which live in the `extenv` directory).
simplify_cfg: rename some passes so that they make more sense
I was extremely confused by `SimplifyCfg::ElaborateDrops`, since it runs way later than drop elaboration. It is used e.g. in `mir-opt/retag.rs` even though that pass doesn't care about drop elaboration at all.
"Early opt" is also very confusing since that makes it sounds like it runs early during optimizations, i.e. on runtime MIR, but actually it runs way before that.
So I decided to rename
- early-opt -> post-analysis
- elaborate-drops -> pre-optimizations
I am open to other suggestions.
Detect when move of !Copy value occurs within loop and should likely not be cloned
When encountering a move error on a value within a loop of any kind,
identify if the moved value belongs to a call expression that should not
be cloned and avoid the semantically incorrect suggestion. Also try to
suggest moving the call expression outside of the loop instead.
```
error[E0382]: use of moved value: `vec`
--> $DIR/recreating-value-in-loop-condition.rs:6:33
|
LL | let vec = vec!["one", "two", "three"];
| --- move occurs because `vec` has type `Vec<&str>`, which does not implement the `Copy` trait
LL | while let Some(item) = iter(vec).next() {
| ----------------------------^^^--------
| | |
| | value moved here, in previous iteration of loop
| inside of this loop
|
note: consider changing this parameter type in function `iter` to borrow instead if owning the value isn't necessary
--> $DIR/recreating-value-in-loop-condition.rs:1:17
|
LL | fn iter<T>(vec: Vec<T>) -> impl Iterator<Item = T> {
| ---- ^^^^^^ this parameter takes ownership of the value
| |
| in this function
help: consider moving the expression out of the loop so it is only moved once
|
LL ~ let mut value = iter(vec);
LL ~ while let Some(item) = value.next() {
|
```
We use the presence of a `break` in the loop that would be affected by
the moved value as a heuristic for "shouldn't be cloned".
Fix https://github.com/rust-lang/rust/issues/121466.
---
*Point at continue and break that might be in the wrong place*
Sometimes move errors are because of a misplaced `continue`, but we didn't
surface that anywhere. Now when there are more than one set of nested loops
we show them out and point at the `continue` and `break` expressions within
that might need to go elsewhere.
```
error[E0382]: use of moved value: `foo`
--> $DIR/nested-loop-moved-value-wrong-continue.rs:46:18
|
LL | for foo in foos {
| ---
| |
| this reinitialization might get skipped
| move occurs because `foo` has type `String`, which does not implement the `Copy` trait
...
LL | for bar in &bars {
| ---------------- inside of this loop
...
LL | baz.push(foo);
| --- value moved here, in previous iteration of loop
...
LL | qux.push(foo);
| ^^^ value used here after move
|
note: verify that your loop breaking logic is correct
--> $DIR/nested-loop-moved-value-wrong-continue.rs:41:17
|
LL | for foo in foos {
| ---------------
...
LL | for bar in &bars {
| ----------------
...
LL | continue;
| ^^^^^^^^ this `continue` advances the loop at line 33
help: consider moving the expression out of the loop so it is only moved once
|
LL ~ let mut value = baz.push(foo);
LL ~ for bar in &bars {
LL |
...
LL | if foo == *bar {
LL ~ value;
|
help: consider cloning the value if the performance cost is acceptable
|
LL | baz.push(foo.clone());
| ++++++++
```
Fix https://github.com/rust-lang/rust/issues/92531.
Sometimes move errors are because of a misplaced `continue`, but we didn't
surface that anywhere. Now when there are more than one set of nested loops
we show them out and point at the `continue` and `break` expressions within
that might need to go elsewhere.
```
error[E0382]: use of moved value: `foo`
--> $DIR/nested-loop-moved-value-wrong-continue.rs:46:18
|
LL | for foo in foos {
| ---
| |
| this reinitialization might get skipped
| move occurs because `foo` has type `String`, which does not implement the `Copy` trait
...
LL | for bar in &bars {
| ---------------- inside of this loop
...
LL | baz.push(foo);
| --- value moved here, in previous iteration of loop
...
LL | qux.push(foo);
| ^^^ value used here after move
|
note: verify that your loop breaking logic is correct
--> $DIR/nested-loop-moved-value-wrong-continue.rs:41:17
|
LL | for foo in foos {
| ---------------
...
LL | for bar in &bars {
| ----------------
...
LL | continue;
| ^^^^^^^^ this `continue` advances the loop at line 33
help: consider moving the expression out of the loop so it is only moved once
|
LL ~ let mut value = baz.push(foo);
LL ~ for bar in &bars {
LL |
...
LL | if foo == *bar {
LL ~ value;
|
help: consider cloning the value if the performance cost is acceptable
|
LL | baz.push(foo.clone());
| ++++++++
```
Fix#92531.
When encountering a move error on a value within a loop of any kind,
identify if the moved value belongs to a call expression that should not
be cloned and avoid the semantically incorrect suggestion. Also try to
suggest moving the call expression outside of the loop instead.
```
error[E0382]: use of moved value: `vec`
--> $DIR/recreating-value-in-loop-condition.rs:6:33
|
LL | let vec = vec!["one", "two", "three"];
| --- move occurs because `vec` has type `Vec<&str>`, which does not implement the `Copy` trait
LL | while let Some(item) = iter(vec).next() {
| ----------------------------^^^--------
| | |
| | value moved here, in previous iteration of loop
| inside of this loop
|
note: consider changing this parameter type in function `iter` to borrow instead if owning the value isn't necessary
--> $DIR/recreating-value-in-loop-condition.rs:1:17
|
LL | fn iter<T>(vec: Vec<T>) -> impl Iterator<Item = T> {
| ---- ^^^^^^ this parameter takes ownership of the value
| |
| in this function
help: consider moving the expression out of the loop so it is only moved once
|
LL ~ let mut value = iter(vec);
LL ~ while let Some(item) = value.next() {
|
```
We use the presence of a `break` in the loop that would be affected by
the moved value as a heuristic for "shouldn't be cloned".
Fix#121466.
Delegation: fix ICE on duplicated associative items
Currently, functions delegation is only supported for delegation items with early resolved paths e.g. free functions and trait methods. During name resolution, information about function signatures is collected, including the number of parameters and whether there are self arguments. This information is then used when lowering from a delegation item into a regular function(`rustc_ast_lowering/src/delegation.rs`). The signature is usually inherited from path resolution id(`path_id`). However, in the case of trait impls `path_id` and `item_id` may be different:
```rust
trait Trait {
fn foo(&self) -> u32 { 0 }
}
struct S;
mod to_reuse {
use crate::S;
pub fn foo(_: &S) -> u32 { 0 }
}
impl Trait for S {
reuse to_reuse::foo { self }
//~^ The signature should be inherited from item id instead of resolution id
}
```
Let's now consider an example from [issue](https://github.com/rust-lang/rust/issues/119920). Due to duplicated associative elements partial resolution for one of them will not be recorded:
9023f908cf/compiler/rustc_resolve/src/late.rs (L3153-L3162)
Which leads to an incorrect `is_in_trait_impl`
9023f908cf/compiler/rustc_ast_lowering/src/item.rs (L981-L986)
Which leads to an incorrect id for signature inheritance
9023f908cf/compiler/rustc_ast_lowering/src/delegation.rs (L99-L105)
Which lead to an ICE from original issue.
This patch fixes wrong `is_in_trait_impl` calculation.
fixes https://github.com/rust-lang/rust/issues/119920
fix `long-linker-command-lines` failure caused by `rust.rpath=false`
Fixes `long-linker-command-lines` test failure (which happens when `rust.rpath` is set to `false`) by adjusting `LD_LIBRARY_PATH`.
Fixes https://github.com/rust-lang/rust/issues/90921
Split refining_impl_trait lint into _reachable, _internal variants
As discussed in https://github.com/rust-lang/rust/issues/119535#issuecomment-1909352040:
> We discussed this today in triage and developed a consensus to:
>
> * Add a separate lint against impls that refine a return type defined with RPITIT even when the trait is not crate public.
> * Place that in a lint group along with the analogous crate public lint.
> * Create an issue to solicit feedback on these lints (or perhaps two separate ones).
> * Have the warnings displayed with each lint reference this issue in a similar manner to how we do that today with the required `Self: '0'` bound on GATs.
> * Make a note to review this feedback on 2-3 release cycles.
This points users to https://github.com/rust-lang/rust/issues/121718 to leave feedback.
Stop walking the bodies of statics for reachability, and evaluate them instead
cc `@saethlin` `@RalfJung`
cc #119214
This reuses the `DefIdVisitor` from `rustc_privacy`, because they basically try to do the same thing.
This PR's changes can probably be extended to constants, too, but let's tackle that separately, it's likely more involved.
`f16` and `f128` step 3: compiler support & feature gate
Continuation of https://github.com/rust-lang/rust/pull/121841, another portion of https://github.com/rust-lang/rust/pull/114607
This PR exposes the new types to the world and adds a feature gate. Marking this as a draft because I need some feedback on where I did the feature gate check. It also does not yet catch type via suffixed literals (so the feature gate test will fail, probably some others too because I haven't belssed).
If there is a better place to check all types after resolution, I can do that. If not, I figure maybe I can add a second gate location in AST when it checks numeric suffixes.
Unfortunately I still don't think there is much testing to be done for correctness (codegen tests or parsed value checks) until we have basic library support. I think that will be the next step.
Tracking issue: https://github.com/rust-lang/rust/issues/116909
r? `@compiler-errors`
cc `@Nilstrieb`
`@rustbot` label +F-f16_and_f128
Safe Transmute: Use 'not yet supported', not 'unspecified' in errors
We can (and will) support analyzing the transmutability of types whose layouts aren't completely specified by its repr. This change ensures that the error messages remain sensible after this support lands.
r? ``@compiler-errors``
Visually mark 👻hidden👻 items with document-hidden-items
Fixes#122485
This adds a 👻 in the item list (much like the 🔒 used for private items), and also shows `#[doc(hidden)]` in the code view, where `pub(crate)` etc gets shown for private items.
This does not do anything for enum variants, if people have ideas. I think we can just show the attribute.
Detect calls to .clone() on T: !Clone types on borrowck errors
When encountering a lifetime error on a type that *holds* a type that doesn't implement `Clone`, explore the item's body for potential calls to `.clone()` that are only cloning the reference `&T` instead of `T` because `T: !Clone`. If we find this, suggest `T: Clone`.
```
error[E0502]: cannot borrow `*list` as mutable because it is also borrowed as immutable
--> $DIR/clone-on-ref.rs:7:5
|
LL | for v in list.iter() {
| ---- immutable borrow occurs here
LL | cloned_items.push(v.clone())
| ------- this call doesn't do anything, the result is still `&T` because `T` doesn't implement `Clone`
LL | }
LL | list.push(T::default());
| ^^^^^^^^^^^^^^^^^^^^^^^ mutable borrow occurs here
LL |
LL | drop(cloned_items);
| ------------ immutable borrow later used here
|
help: consider further restricting this bound
|
LL | fn foo<T: Default + Clone>(list: &mut Vec<T>) {
| +++++++
```
```
error[E0505]: cannot move out of `x` because it is borrowed
--> $DIR/clone-on-ref.rs:23:10
|
LL | fn qux(x: A) {
| - binding `x` declared here
LL | let a = &x;
| -- borrow of `x` occurs here
LL | let b = a.clone();
| ------- this call doesn't do anything, the result is still `&A` because `A` doesn't implement `Clone`
LL | drop(x);
| ^ move out of `x` occurs here
LL |
LL | println!("{b:?}");
| ----- borrow later used here
|
help: consider annotating `A` with `#[derive(Clone)]`
|
LL + #[derive(Clone)]
LL | struct A;
|
```
Fix#48677.
Consolidate WF for aliases
Make RPITs/TAITs/weak (type) aliases/projections all enforce:
1. their nominal predicates
2. their args are WF
This possibly does extra work, but is also nice for consistency sake.
r? lcnr
We can (and will) support analyzing the transmutability of types
whose layouts aren't completely specified by its repr. This change
ensures that the error messages remain sensible after this support
lands.
rustdoc: add `--test-builder-wrapper` arg to support wrappers such as RUSTC_WRAPPER when building doctests
Currently, `rustdoc` builds test crates with `rustc` directly instead of using [`RUSTC_WRAPPER`](https://doc.rust-lang.org/cargo/reference/config.html#buildrustc-wrapper) (if any is set).
This causes build issues in build systems that use `cargo` but tweak linking flags by setting the `RUSTC_WRAPPER` environment variable.
This change is not meant to be final--it's only a minimal proof of concept.
Please advise on the best way to proceed.
Open questions:
- [x] Does supporting the `rustc` wrappers make sense?
- yes, `cargo-miri` for example needs a "hack" to workaround the issue
- [X] What environment variable(s) should be read for the rustc wrapper? Should `rustdoc` [use the same names as `cargo`](https://doc.rust-lang.org/cargo/reference/config.html#buildrustc-wrapper)?
- None, since `rustdoc` takes arguments
- [X] What name should be used for a `rustdoc` CLI option?
- `--test-builder-wrapper`
- [X] Should a separate workspace wrapper (like `RUSTC_WORKSPACE_WRAPPER`) be supported?
- `--test-builder-wrapper` can be passed multiple times to get multiple wrappers passed
- [X] How/where should this be documented? It's not obvious to all users that `cargo doc` actually causes `rustdoc` to compile tests with rust
- Added doc to `src/doc/rustdoc/src/command-line-arguments.md` per `@GuillaumeGomez`
link.exe: Don't embed full path to PDB file in binary.
This PR makes `rustc` unconditionally pass `/PDBALTPATH:%_PDB%` to MSVC-style linkers, causing the linker to only embed the filename of the PDB in the binary instead of the full path. This will help implement the [trim-paths RFC](https://github.com/rust-lang/rust/issues/111540) for `*-msvc` targets.
Passing `/PDBALTPATH:%_PDB%` to the linker is already done by many projects that need reproducible builds and [debugger's should still be able to find the PDB](https://learn.microsoft.com/cpp/build/reference/pdbpath) if it is in the same directory as the binary.
r? `@ghost`
Fixes https://github.com/rust-lang/rust/issues/87825
Ensure RPITITs are created before def-id freezing
From the test:
```rust
// `ty::Error` in a trait ref will silence any missing item errors, but will also
// prevent the `associated_items` query from being called before def ids are frozen.
```
Essentially, the code that checks that `impl`s have all their items (`check_impl_items_against_trait`) is also (implicitly) responsible for fetching the `associated_items` query before, but since we early return here:
c2901f5435/compiler/rustc_hir_analysis/src/check/check.rs (L732-L737)
...that means that this never happens for trait refs that reference errors.
Fixes#122518
r? oli-obk
preserve span when evaluating mir::ConstOperand
This lets us show to the user where they were using the faulty const (which can be quite relevant when generics are involved).
I wonder if we should change "erroneous constant encountered" to something like "the above error was encountered while evaluating this constant" or so, to make this more similar to what the collector emits when showing a "backtrace" of where things get monomorphized? It seems a bit strange to rely on the order of emitted diagnostics for that but it seems the collector already [does that](da8a8c9223/compiler/rustc_monomorphize/src/collector.rs (L472-L475)).
Rollup of 10 pull requests
Successful merges:
- #117118 ([AIX] Remove AixLinker's debuginfo() implementation)
- #121650 (change std::process to drop supplementary groups based on CAP_SETGID)
- #121764 (Make incremental sessions identity no longer depend on the crate names provided by source code)
- #122212 (Copy byval argument to alloca if alignment is insufficient)
- #122322 (coverage: Initial support for branch coverage instrumentation)
- #122373 (Fix the conflict problem between the diagnostics fixes of lint `unnecessary_qualification` and `unused_imports`)
- #122479 (Implement `Duration::as_millis_{f64,f32}`)
- #122487 (Rename `StmtKind::Local` variant into `StmtKind::Let`)
- #122498 (Update version of cc crate)
- #122503 (Make `SubdiagMessageOp` well-formed)
r? `@ghost`
`@rustbot` modify labels: rollup
Fix the conflict problem between the diagnostics fixes of lint `unnecessary_qualification` and `unused_imports`
fixes#121331
For an `item` that triggers lint unnecessary_qualification, if the `use item` which imports this item is also trigger unused import, fixing the two lints at the same time may lead to the problem that the `item` cannot be found.
This PR will avoid reporting lint unnecessary_qualification when conflict occurs.
r? ``@petrochenkov``
coverage: Initial support for branch coverage instrumentation
(This is a review-ready version of the changes that were drafted in #118305.)
This PR adds support for branch coverage instrumentation, gated behind the unstable flag value `-Zcoverage-options=branch`. (Coverage instrumentation must also be enabled with `-Cinstrument-coverage`.)
During THIR-to-MIR lowering (MIR building), if branch coverage is enabled, we collect additional information about branch conditions and their corresponding then/else blocks. We inject special marker statements into those blocks, so that the `InstrumentCoverage` MIR pass can reliably identify them even after the initially-built MIR has been simplified and renumbered.
The rest of the changes are mostly just plumbing needed to gather up the information that was collected during MIR building, and include it in the coverage metadata that we embed in the final binary.
Note that `llvm-cov show` doesn't print branch coverage information in its source views by default; that needs to be explicitly enabled with `--show-branches=count` or similar.
---
The current implementation doesn't have any support for instrumenting `if let` or let-chains. I think it's still useful without that, and adding it would be non-trivial, so I'm happy to leave that for future work.
more eagerly instantiate binders
The old solver sometimes incorrectly used `sub`, change it to explicitly instantiate binders and use `eq` instead. While doing so I also moved the instantiation before the normalize calls. This caused some observable changes, will explain these inline. This PR therefore requires a crater run and an FCP.
r? types
Add a test that `f16` and `f128` are usable with the feature gate
enabled, as well as a test that user types with the same name as
primitives are not improperly gated.
Includes related tests and documentation pages.
Michael Goulet: Don't issue feature error in resolver for f16/f128
unless finalize
Co-authored-by: Michael Goulet <michael@errs.io>
Ungate the `UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES` lint
This was missed during stablisation of the `#[diagnostic]` attribute namespace.
Fixes#122446
add test ensuring simd codegen checks don't run when a static assertion failed
stdarch relies on this to ensure that SIMD indices are in bounds.
I would love to know why this works, but I can't figure out where codegen decides to not codegen a function if a required-const does not evaluate. `@oli-obk` `@bjorn3` do you have any idea?
rustdoc-search: depth limit `T<U>` -> `U` unboxing
Profiler output:
https://notriddle.com/rustdoc-html-demo-9/search-unbox-limit/ (the only significant change is that one of the `rust` tests went from 378416ms to 16ms).
This is a performance enhancement aimed at a problem I found while using type-driven search on the Rust compiler. It is caused by [`Interner`], a trait with 41 associated types, many of which recurse back to `Self` again.
This caused search.js to struggle. It eventually terminates, after about 10 minutes of turning my PC into a space header, but it's doing `41!` unifications and that's too slow.
[`Interner`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/trait.Interner.html
const-eval: organize and extend tests for required-consts
This includes some tests that are known-broken and hence disabled (due to https://github.com/rust-lang/rust/issues/107503).
r? `````@oli-obk`````
Add methods to create StableMIR constant
I've been experimenting with transforming the StableMIR to instrument the code with potential UB checks.
The modified body will only be used by our analysis tool, however, constants in StableMIR must be backed by rustc constants. Thus, I'm adding a few functions to build constants, such as building string and other primitives.
One question I have is whether we should create a global allocation instead for strings.
r? ``````@oli-obk``````
rustdoc-search: search types by higher-order functions
This feature extends rustdoc with syntax and search index information for searching function pointers and closures (Higher-Order Functions, or HOF). Part of https://github.com/rust-lang/rust/issues/60485
This PR adds two syntaxes: a high-level one for finding any kind of HOF, and a direct implementation of the parenthesized path syntax that Rust itself uses.
## Preview pages
| Query | Results |
|-------|---------|
| [`option<T>, (fnonce (T) -> bool) -> option<T>`][optionfilter] | `Option::filter` |
| [`option<T>, (T -> bool) -> option<T>`][optionfilter2] | `Option::filter` |
Updated chapter of the book: https://notriddle.com/rustdoc-html-demo-9/search-hof/rustdoc/read-documentation/search.html
[optionfilter]: https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=option<T>%2C+(fnonce+(T)+->+bool)+->+option<T>&filter-crate=std
[optionfilter2]: https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=option<T>%2C+(T+->+bool)+->+option<T>&filter-crate=std
## Motivation
When type-based search was first landed, it was directly [described as incomplete][a comment].
[a comment]: https://github.com/rust-lang/rust/pull/23289#issuecomment-79437386
Filling out the missing functionality is going to mean adding support for more of Rust's [type expression] syntax, such as references, raw pointers, function pointers, and closures. This PR adds function pointers and closures.
[type expression]: https://doc.rust-lang.org/reference/types.html#type-expressions
There's been demand for something "like Hoogle, but for Rust" expressed a few times [1](https://www.reddit.com/r/rust/comments/y8sbid/is_there_a_website_like_haskells_hoogle_for_rust/) [2](https://users.rust-lang.org/t/rust-equivalent-of-haskells-hoogle/102280) [3](https://internals.rust-lang.org/t/std-library-inclusion-policy/6852/2) [4](https://discord.com/channels/442252698964721669/448238009733742612/1109502307495858216). Some of them just don't realize what functionality already exists ([`Duration -> u64`](https://doc.rust-lang.org/nightly/std/?search=duration%20-%3E%20u64) already works), but a lot of them specifically want to search for higher-order functions like option combinators.
## Guide-level explanation (from the Rustdoc book)
To search for a function that accepts a function as a parameter, like `Iterator::all`, wrap the nested signature in parenthesis, as in [`Iterator<T>, (T -> bool) -> bool`][iterator-all]. You can also search for a specific closure trait, such as `Iterator<T>, (FnMut(T) -> bool) -> bool`, but you need to know which one you want.
[iterator-all]: https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=Iterator<T>%2C+(T+->+bool)+->+bool&filter-crate=std
## Reference-level description (also from the Rustdoc book)
### Primitives with Special Syntax
<table>
<thead>
<tr>
<th>Shorthand</th>
<th>Explicit names</th>
</tr>
</thead>
<tbody>
<tr><td colspan="2">Before this PR</td></tr>
<tr>
<td><code>[]</code></td>
<td><code>primitive:slice</code> and/or <code>primitive:array</code></td>
</tr>
<tr>
<td><code>[T]</code></td>
<td><code>primitive:slice<T></code> and/or <code>primitive:array<T></code></td>
</tr>
<tr>
<td><code>!</code></td>
<td><code>primitive:never</code></td>
</tr>
<tr>
<td><code>()</code></td>
<td><code>primitive:unit</code> and/or <code>primitive:tuple</code></td>
</tr>
<tr>
<td><code>(T)</code></td>
<td><code>T</code></td>
</tr>
<tr>
<td><code>(T,)</code></td>
<td><code>primitive:tuple<T></code></td>
</tr>
<tr><td colspan="2">After this PR</td></tr>
<tr>
<td><code>(T, U -> V, W)</code></td>
<td><code>fn(T, U) -> (V, W)</code>, Fn, FnMut, and FnOnce</td>
</tr>
</tbody>
</table>
The `->` operator has lower precedence than comma. If it's not wrapped in brackets, it delimits the return value for the function being searched for. To search for functions that take functions as parameters, use parenthesis.
### Search query grammar
```ebnf
ident = *(ALPHA / DIGIT / "_")
path = ident *(DOUBLE-COLON ident) [BANG]
slice-like = OPEN-SQUARE-BRACKET [ nonempty-arg-list ] CLOSE-SQUARE-BRACKET
tuple-like = OPEN-PAREN [ nonempty-arg-list ] CLOSE-PAREN
arg = [type-filter *WS COLON *WS] (path [generics] / slice-like / tuple-like)
type-sep = COMMA/WS *(COMMA/WS)
nonempty-arg-list = *(type-sep) arg *(type-sep arg) *(type-sep) [ return-args ]
generic-arg-list = *(type-sep) arg [ EQUAL arg ] *(type-sep arg [ EQUAL arg ]) *(type-sep)
normal-generics = OPEN-ANGLE-BRACKET [ generic-arg-list ] *(type-sep)
CLOSE-ANGLE-BRACKET
fn-like-generics = OPEN-PAREN [ nonempty-arg-list ] CLOSE-PAREN [ RETURN-ARROW arg ]
generics = normal-generics / fn-like-generics
return-args = RETURN-ARROW *(type-sep) nonempty-arg-list
exact-search = [type-filter *WS COLON] [ RETURN-ARROW ] *WS QUOTE ident QUOTE [ generics ]
type-search = [ nonempty-arg-list ]
query = *WS (exact-search / type-search) *WS
; unchanged parts of the grammar, like the full list of type filters, are omitted
```
## Future direction
### The remaining type expression grammar
As described in https://github.com/rust-lang/rust/pull/118194, this is another step in the type expression grammar: BareFunction, and the function-like mode of TypePath, are now supported.
* RawPointerType and ReferenceType actually are a priority.
* ImplTraitType and TraitObjectType (and ImplTraitTypeOneBound and TraitObjectTypeOneBound) aren't as much of a priority, since they desugar pretty easily.
### Search subtyping and traits
This is the other major factor that makes it less useful than it should be.
* `iterator<result<t>> -> result<t>` doesn't find `Result::from_iter`. You have to search [`intoiterator<result<t>> -> result<t>`](https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=intoiterator%3Cresult%3Ct%3E%3E%20-%3E%20result%3Ct%3E&filter-crate=std). Nobody's going to search for IntoIterator unless they basically already know about it and don't need the search engine anyway.
* Iterator combinators are usually structs that happen to implement Iterator, like `std::iter::Map`.
To solve these cases, it needs to look at trait implementations, knowing that Iterator is a "subtype of" IntoIterator, and Map is a "subtype of" Iterator, so `iterator -> result` is a subtype of `intoiterator -> result` and `iterator<t>, (t -> u) -> iterator<u>` is a subtype of [`iterator<t>, (t -> u) -> map<t -> u>`](https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=iterator%3Ct%3E%2C%20(t%20-%3E%20u)%20-%3E%20map%3Ct%20-%3E%20u%3E&filter-crate=std).
Downgrade const eval dangling ptr in final to future incompat lint
Short term band-aid for issue #121610, downgrading the prior hard error to a future-incompat lint (tracked in issue #122153).
Note we should not mark #121610 as resolved until after this (or something analogous) is beta backported.
When encountering a lifetime error on a type that *holds* a type that
doesn't implement `Clone`, explore the item's body for potential calls
to `.clone()` that are only cloning the reference `&T` instead of `T`
because `T: !Clone`. If we find this, suggest `T: Clone`.
```
error[E0502]: cannot borrow `*list` as mutable because it is also borrowed as immutable
--> $DIR/clone-on-ref.rs:7:5
|
LL | for v in list.iter() {
| ---- immutable borrow occurs here
LL | cloned_items.push(v.clone())
| ------- this call doesn't do anything, the result is still `&T` because `T` doesn't implement `Clone`
LL | }
LL | list.push(T::default());
| ^^^^^^^^^^^^^^^^^^^^^^^ mutable borrow occurs here
LL |
LL | drop(cloned_items);
| ------------ immutable borrow later used here
|
help: consider further restricting this bound
|
LL | fn foo<T: Default + Clone>(list: &mut Vec<T>) {
| +++++++
```
```
error[E0505]: cannot move out of `x` because it is borrowed
--> $DIR/clone-on-ref.rs:23:10
|
LL | fn qux(x: A) {
| - binding `x` declared here
LL | let a = &x;
| -- borrow of `x` occurs here
LL | let b = a.clone();
| ------- this call doesn't do anything, the result is still `&A` because `A` doesn't implement `Clone`
LL | drop(x);
| ^ move out of `x` occurs here
LL |
LL | println!("{b:?}");
| ----- borrow later used here
|
help: consider annotating `A` with `#[derive(Clone)]`
|
LL + #[derive(Clone)]
LL | struct A;
|
```
Safe Transmute: Require that source referent is smaller than destination
`BikeshedIntrinsicFrom` currently models transmute-via-union; i.e., it attempts to provide a `where` bound for this function:
```rust
pub unsafe fn transmute_via_union<Src, Dst>(src: Src) -> Dst {
use core::mem::*;
#[repr(C)]
union Transmute<T, U> {
src: ManuallyDrop<T>,
dst: ManuallyDrop<U>,
}
let transmute = Transmute { src: ManuallyDrop::new(src) };
// SAFETY: The caller must guarantee that the transmutation is safe.
let dst = transmute.dst;
ManuallyDrop::into_inner(dst)
}
```
A quirk of this model is that it admits padding extensions in value-to-value transmutation: The destination type can be bigger than the source type, so long as the excess consists of uninitialized bytes. However, this isn't permissible for reference-to-reference transmutations (introduced in #110662) — extra referent bytes cannot come from thin air.
This PR patches our analysis for reference-to-reference transmutations to require that the destination referent is no larger than the source referent.
r? `@compiler-errors`
pattern analysis: remove `MaybeInfiniteInt::JustAfterMax`
It was inherited from before half-open ranges, but it doesn't pull its weight anymore. We lose a tiny bit of diagnostic precision as can be seen in the test. I'm generally in favor of half-open ranges over explicit `x..=MAX` ranges anyway.
The source referent absolutely must be smaller than the destination
referent of a ref-to-ref transmute; the excess bytes referenced
cannot arise from thin air, even if those bytes are uninitialized.
Represent `Result<usize, Box<T>>` as ScalarPair(i64, ptr)
This allows types like `Result<usize, std::io::Error>` (and integers of differing sign, e.g. `Result<u64, i64>`) to be passed in a pair of registers instead of through memory, like `Result<u64, u64>` or `Result<Box<T>, Box<U>>` are today.
Fixes#97540.
r? `@ghost`
I attempted to do this in a manner that preserved the line numbers to reduce the
review effort on the resulting diff, but we still have to deal with the
ramifications of how a future-incompat lint behaves compared to a hard-error (in
terms of its impact on the diagnostic output).
delay expand macro bang when there has indeterminate path
Related #98291
I will attempt to clarify the root problem through several examples:
Firstly,
```rs
// rustc code.rs --edition=2018
macro_rules! wrap {
() => {
macro_rules! _a {
() => {
"Hello world"
};
}
};
}
wrap!();
use _a as a;
fn main() {
format_args!(_a!());
}
```
The above case will compile successfully because `_a` is defined after the `wrap` expaned, ensuring `_a` can be resolved without any issues.
And,
```rs
// rustc code.rs --edition=2018
macro_rules! wrap {
() => {
macro_rules! _a {
() => {
"Hello world"
};
}
};
}
wrap!();
use _a as a;
fn main() {
format_args!("{}", a!());
}
```
The above example will also compile successfully because the `parse_args` in `expand_format_args_impl` will return a value `MacroInput { fmtstr: Expr::Lit::Str, args: [Expr::MacroCall]}`. Since the graph for `args` will be build lately, `a` will eventually be resolved.
However, in the case of:
```rs
// rustc code.rs --edition=2018
macro_rules! wrap {
() => {
macro_rules! _a {
() => {
"Hello world"
};
}
};
}
wrap!();
use _a as a;
fn main() {
format_args!(a!());
}
```
The result of `parse_args` is `MacroInput {fmtstr: Expr::Lit::Macro, args: [] }`, we attempt to expand `fmtstr` **eagerly** within `expr_to_spanned_string`. Although we have recorded `(root, _a)` into resolutions, `use _a as a` is an indeterminate import, which will not try to resolve under the conditions of `expander.monotonic = false`.
Therefore, I've altered the strategy for resolving indeterminate imports, ensuring it will also resolve during eager expansion. This could be a significant change to the resolution infra. However, I think it's acceptable if the goal of avoiding resolution under eager expansion is to save time.
r? `@petrochenkov`
Rollup of 10 pull requests
Successful merges:
- #121820 (pattern analysis: Store field indices in `DeconstructedPat` to avoid virtual wildcards)
- #121908 (match lowering: don't collect test alternatives ahead of time)
- #122203 (Add `intrinsic_name` to get plain intrinsic name)
- #122226 (coverage: Remove or migrate all unstable values of `-Cinstrument-coverage`)
- #122255 (Use `min_exhaustive_patterns` in core & std)
- #122360 ( Don't Create `ParamCandidate` When Obligation Contains Errors )
- #122383 (Enable PR tracking review assignment for rust-lang/rust)
- #122386 (Move `Once` implementations to `sys`)
- #122400 (Fix ICE in diagnostics for parenthesized type arguments)
- #122410 (rustdoc: do not preload fonts when browsing locally)
r? `@ghost`
`@rustbot` modify labels: rollup
