This rewrite makes the cache-updating nature of the function slightly clearer, using the Entry API into the hash table for region names to capture the update-insert nature of the method. May be marginally more efficient since it only runtime-borrows the map once, but in this context the performance impact is almost certainly completely negligible.
When encountering an `if let` tail expression without an `else` arm for an
enum with a single variant, suggest writing an irrefutable `let` binding
instead.
```
error[E0317]: `if` may be missing an `else` clause
--> $DIR/irrefutable-if-let-without-else.rs:8:5
|
LL | fn foo(x: Enum) -> i32 {
| --- expected `i32` because of this return type
LL | / if let Enum::Variant(value) = x {
LL | | value
LL | | }
| |_____^ expected `i32`, found `()`
|
= note: `if` expressions without `else` evaluate to `()`
= help: consider adding an `else` block that evaluates to the expected type
help: consider using an irrefutable `let` binding instead
|
LL ~ let Enum::Variant(value) = x;
LL ~ value
|
```
Fix#61788.
That is, change `diagnostic_outside_of_impl` and
`untranslatable_diagnostic` from `allow` to `deny`, because more than
half of the compiler has be converted to use translated diagnostics.
This commit removes more `deny` attributes than it adds `allow`
attributes, which proves that this change is warranted.
Introduce support for `async` bound modifier on `Fn*` traits
Adds `async` to the list of `TraitBoundModifiers`, which instructs AST lowering to map the trait to an async flavor of the trait. For now, this is only supported for `Fn*` to `AsyncFn*`, and I expect that this manual mapping via lang items will be replaced with a better system in the future.
The motivation for adding these bounds is to separate the users of async closures from the exact trait desugaring of their callable bounds. Instead of users needing to be concerned with the `AsyncFn` trait, they should be able to write `async Fn()` and it will desugar to whatever underlying trait we decide is best for the lowering of async closures.
Note: rustfmt support can be done in the rustfmt repo after a subtree sync.
pattern_analysis: Gracefully abort on type incompatibility
This leaves the option for a consumer of the crate to return `Err` instead of panicking on type error. rust-analyzer could use that (e.g. https://github.com/rust-lang/rust-analyzer/issues/15808).
Since the only use of `TypeCx::bug` is in `Constructor::is_covered_by`, it is tempting to return `false` instead of `Err()`, but that would cause "non-exhaustive match" false positives.
r? `@compiler-errors`
All the other `emit`/`emit_diagnostic` methods were recently made
consuming (e.g. #119606), but this one wasn't. But it makes sense to.
Much of this is straightforward, and lots of `clone` calls are avoided.
There are a couple of tricky bits.
- `Emitter::primary_span_formatted` no longer takes a `Diagnostic` and
returns a pair. Instead it takes the two fields from `Diagnostic` that
it used (`span` and `suggestions`) as `&mut`, and modifies them. This
is necessary to avoid the cloning of `diag.children` in two emitters.
- `from_errors_diagnostic` is rearranged so various uses of `diag` occur
before the consuming `emit_diagnostic` call.
target: default to the medium code model on LoongArch targets
The Rust LoongArch targets have been using the default LLVM code model so far, which is "small" in LLVM-speak and "normal" in LoongArch-speak. As [described][1] in the "Code Model" section of LoongArch ELF psABI spec v20231219, one can only make function calls as far as ±128MiB with the "normal" code model; this is insufficient for very large software containing Rust components that needs to be linked into the big text section, such as Chromium.
Because:
* we do not want to ask users to recompile std if they are to build such software,
* objects compiled with larger code models can be linked with those with smaller code models without problems, and
* the "medium" code model is comparable to the "small"/"normal" one performance-wise (same data access pattern; each function call becomes 2-insn long and indirect, but this may be relaxed back into the direct 1-insn form in a future LLVM version), but is able to perform function calls within ±128GiB,
it is better to just switch the targets to the "medium" code model, which is also "medium" in LLVM-speak.
[1]: https://github.com/loongson/la-abi-specs/blob/v2.30/laelf.adoc#code-models
riscv only supports split_debuginfo=off for now
Disable packed/unpacked options for riscv linux/android. Other riscv targets already only have the off option.
The packed/unpacked options might be supported in the future. See upstream issue for more details:
https://github.com/llvm/llvm-project/issues/56642Fixes#110224
make matching on NaN a hard error, and remove the rest of illegal_floating_point_literal_pattern
These arms would never be hit anyway, so the pattern makes little sense. We have had a future-compat lint against float matches in general for a *long* time, so I hope we can get away with immediately making this a hard error.
This is part of implementing https://github.com/rust-lang/rfcs/pull/3535.
Closes https://github.com/rust-lang/rust/issues/41620 by removing the lint.
https://github.com/rust-lang/reference/pull/1456 updates the reference to match.
The Rust LoongArch targets have been using the default LLVM code model
so far, which is "small" in LLVM-speak and "normal" in LoongArch-speak.
As described in the "Code Model" section of LoongArch ELF psABI spec
v20231219 [1], one can only make function calls as far as ±128MiB with
the "normal" code model; this is insufficient for very large software
containing Rust components that needs to be linked into the big text
section, such as Chromium.
Because:
* we do not want to ask users to recompile std if they are to build
such software,
* objects compiled with larger code models can be linked with those
with smaller code models without problems, and
* the "medium" code model is comparable to the "small"/"normal" one
performance-wise (same data access pattern; each function call
becomes 2-insn long and indirect, but this may be relaxed back into
the direct 1-insn form in a future LLVM version), but is able to
perform function calls within ±128GiB,
it is better to just switch the targets to the "medium" code model,
which is also "medium" in LLVM-speak.
[1]: https://github.com/loongson/la-abi-specs/blob/v2.30/laelf.adoc#code-models
coverage: Improve handling of function/closure spans
This is a combination of some loosely-related changes that touch the same code:
1. Make unexpansion of closure bodies more precise, by unexpanding back to the context of the closure declaration, instead of unexpanding all the way back to the top-level context. This preserves the way we handle async desugaring and closures containing a single bang-macro, while also giving better results for closures defined in macros.
2. Skip the normal span-refinement code when dealing with the trivial outer part of an async function.
3. Be more explicit about the fact that `fn_sig_span` has been extended to the start of the function body, and is not necessarily present.
---
`@rustbot` label +A-code-coverage
Move predicate, region, and const stuff into their own modules in middle
This PR mostly moves things around, and in a few cases adds some `ty::` to the beginning of names to avoid one-off imports.
I don't mean this to be the most *thorough* move/refactor. I just generally wanted to begin to split up `ty/mod.rs` and `ty/sty.rs` which are huge and hard to distinguish, and have a lot of non-ty stuff in them.
r? lcnr
This sidesteps the normal span refinement code in cases where we know that we
are only dealing with the special signature span that represents having called
an async function.
The two kinds of delayed bug have quite different semantics so a
stronger conceptual separation is nice. (`is_error` is a good example,
because the two kinds have different behaviour.)
The commit also moves the `DelayedBug` variant after `Error` in `Level`,
to reflect the fact that it's weaker than `Error` -- it might trigger an
error but also might not. (The pre-existing `downgrade_to_delayed_bug`
function also reflects the notion that delayed bugs are lower/after
normal errors.)
Plus it condenses some of the comments on `Level` into a table, for
easier reading, and introduces `can_be_top_or_sub` to indicate which
levels can be used in top-level diagnostics vs. subdiagnostics.
Finally, it renames `DiagCtxtInner::span_delayed_bugs` as
`DiagCtxtInner::delayed_bugs`. The `span_` prefix is unnecessary because
some delayed bugs don't have a span.
- Combine two different blocks involving
`diagnostic.level.get_expectation_id()` into one.
- Combine several `if`s involving `diagnostic.level` into a single
`match`.
This requires reordering some of the operations, but this has no
functional effect.
Rollup of 8 pull requests
Successful merges:
- #119759 (Add FileCheck annotations to dataflow-const-prop tests)
- #120323 (On E0277 be clearer about implicit `Sized` bounds on type params and assoc types)
- #120473 (Only suggest removal of `as_*` and `to_` conversion methods on E0308)
- #120540 (add test for try-block-in-match-arm)
- #120547 (`#![feature(inline_const_pat)]` is no longer incomplete)
- #120552 (Correctly check `never_type` feature gating)
- #120555 (put pnkfelix (me) back on the review queue.)
- #120556 (Improve the diagnostics for unused generic parameters)
r? `@ghost`
`@rustbot` modify labels: rollup
It doesn't affect behaviour, but makes sense with (a) `FailureNote` having
`()` as its emission guarantee, and (b) in `Level` the `is_error` levels
now are all listed before the non-`is_error` levels.
Rollup of 8 pull requests
Successful merges:
- #120484 (Avoid ICE when is_val_statically_known is not of a supported type)
- #120516 (pattern_analysis: cleanup manual impls)
- #120517 (never patterns: It is correct to lower `!` to `_`.)
- #120523 (Improve `io::Read::read_buf_exact` error case)
- #120528 (Store SHOULD_CAPTURE as AtomicU8)
- #120529 (Update data layouts in custom target tests for LLVM 18)
- #120531 (Remove a bunch of `has_errors` checks that have no meaningful or the wrong effect)
- #120533 (Correct paths for hexagon-unknown-none-elf platform doc)
r? `@ghost`
`@rustbot` modify labels: rollup
Improve the diagnostics for unused generic parameters
* Don't emit two errors (namely E0091 *and* E0392) for unused type parameters on *lazy* type aliases
* Fix the diagnostic help message of E0392 for *lazy* type aliases: Don't talk about the “fields” of lazy type aliases (use the term “body” instead) and don't suggest `PhantomData` for them, it doesn't make much sense
* Consolidate the diagnostics for E0091 (unused type parameters in type aliases) and E0392 (unused generic parameters due to bivariance) and make it translatable
* Still keep the error codes distinct (for now)
* Naturally leads to better diagnostics for E0091
r? ```@oli-obk``` (to ballast your review load :P) or compiler
Correctly check `never_type` feature gating
Fixes#120542.
The feature wasn't tested on return type of a generic function type, so it got under the radar in https://github.com/rust-lang/rust/pull/120316.
r? ```@compiler-errors```
`#![feature(inline_const_pat)]` is no longer incomplete
Now that borrow checking and safety checking is implemented for inline constant patterns, the incomplete feature status is not necessary. Stabilizing this feature requires more testing and has some of the same unresolved questions as inline constants.
cc #76001
it works when a non-const context that does not enable effects
calls into a const effects-enabled trait. We'd simply suggest the
non-const trait bound in this case consistent to its fallback.
never patterns: It is correct to lower `!` to `_`.
This is just a comment update but a non-trivial one: it is correct to lower `!` patterns as `_`. The reasoning is that `!` matches all the possible values of the type, since the type is empty. Moreover, we do want to warn that the `Err` is redundant in:
```rust
match x {
!,
Err(!),
}
```
which is consistent with `!` behaving like a wildcard.
I did try to introduce `Constructor::Never` and it ended up needing to behave exactly like `Constructor::Wildcard`.
r? ```@compiler-errors```
Avoid ICE when is_val_statically_known is not of a supported type
2 ICE with 1 stone!
1. Implement `llvm.is.constant.ptr` to avoid first ICE in linked issue.
2. return `false` when the argument is not one of `i*`/`f*`/`ptr` to avoid second ICE.
fixes#120480
hir: Remove the generic type parameter from `MaybeOwned`
It's only ever used with a reference to `OwnerInfo` as an argument.
Follow up to https://github.com/rust-lang/rust/pull/120346.
Remove `BorrowckErrors::tainted_by_errors`
This PR removes one of the `tainted_by_errors` occurrences, replacing it with direct use of `ErrorGuaranteed`.
r? `@oli-obk`
Suggest changing type to const parameters if we encounter a type in the trait bound position
The first commit is just drive-by cleanup.
Provide a structured suggestion if the user forgot to prefix a “const parameter” with `const`, e.g., in `struct Tagged<TAG: u64>;`. This happens to me from time to time. Maybe C++ devs are also prone to this mistake given template syntax looks like `template<typename T, uint32_t N>`.
`emit_future_breakage` calls
`self.dcx().take_future_breakage_diagnostics()` and then passes the
result to `self.dcx().emit_future_breakage_report(diags)`. This commit
removes the first of these and lets `emit_future_breakage_report` do the
taking.
It also inlines and removes what is left of `emit_future_breakage`,
which has a single call site.
- `emitted_at` isn't used outside the crate.
- `code` and `messages` are public fields, so there's no point have
trivial getters/setters for them.
- `suggestions` is public, so the comment about "functionality on
`Diagnostic`" isn't needed.
`BorrowckErrors` stores a mix of error and non-error diags in
`buffered`. As a result, it downgrades `DiagnosticBuilder`s to
`Diagnostic`s, losing the emission guarantees, and so has to use a
`tainted_by_errors` field to record whether an error has occurred.
This commit splits `buffered` into `buffered_errors` and
`buffered_non_errors`, keeping them as `DiagnosticBuilder`s and
preserving the emission guarantees.
This also requires fixing a bunch of incorrect lifetimes on
`DiagnosticBuilder` use points.
* Get rid of a typo in a function name
* Rename `currently_processing_generics`: The old name confused me at first since
I assumed it referred to generic *parameters* when it was in fact referring to
generic *arguments*. Generics are typically short for generic params.
* Get rid of a few unwraps by properly leveraging slice patterns
This makes it possible for two nodes/edges in the coverage graph to share the
same counter, without causing the instrumentor to inject unwanted duplicate
counter-increment statements.
When there are two possibilities, both of which use a `String`, it's
nicer to use a struct than an enum. Especially when mapping the contents
into a tuple.
It contains an `i128`, but when creating them we convert any number
outside the range -100..100 to a string, because Fluent uses an `f64`.
It's all a bit strange.
This commit changes the `i128` to an `i32`, which fits safely in
Fluent's `f64`, and removes the -100..100 range check. This means that
only integers outside the range of `i32` will be converted to strings.
```
error[E0277]: the size for values of type `[i32]` cannot be known at compilation time
--> f100.rs:2:33
|
2 | let _ = std::mem::size_of::<[i32]>();
| ^^^^^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `[i32]`
note: required by an implicit `Sized` bound in `std::mem::size_of`
--> /home/gh-estebank/rust/library/core/src/mem/mod.rs:312:22
|
312 | pub const fn size_of<T>() -> usize {
| ^ required by the implicit `Sized` requirement on this bound in `size_of`
```
Fix#120178.
Since the only use of `TypeCx::bug` is in `Constructor::is_covered_by`,
it is tempting to return `false` instead of `Err()`, but that would
cause "non-exhaustive match" false positives.
Don't hash lints differently to non-lints.
`Diagnostic::keys`, which is used for hashing and equating diagnostics, has a surprising behaviour: it ignores children, but only for lints. This was added in #88493 to fix some duplicated diagnostics, but it doesn't seem necessary any more.
This commit removes the special case and only four tests have changed output, with additional errors. And those additional errors aren't exact duplicates, they're just similar. For example, in src/tools/clippy/tests/ui/same_name_method.rs we currently have this error:
```
error: method's name is the same as an existing method in a trait
--> $DIR/same_name_method.rs:75:13
|
LL | fn foo() {}
| ^^^^^^^^^^^
|
note: existing `foo` defined here
--> $DIR/same_name_method.rs:79:9
|
LL | impl T1 for S {}
| ^^^^^^^^^^^^^^^^
```
and with this change we also get this error:
```
error: method's name is the same as an existing method in a trait
--> $DIR/same_name_method.rs:75:13
|
LL | fn foo() {}
| ^^^^^^^^^^^
|
note: existing `foo` defined here
--> $DIR/same_name_method.rs:81:9
|
LL | impl T2 for S {}
|
```
I think printing this second argument is reasonable, possibly even preferable to hiding it. And the other cases are similar.
r? `@estebank`
Provide more context on derived obligation error primary label
Expand the primary span of E0277 when the immediate unmet bound is not what the user wrote:
```
error[E0277]: the trait bound `i32: Bar` is not satisfied
--> f100.rs:6:6
|
6 | <i32 as Foo>::foo();
| ^^^ the trait `Bar` is not implemented for `i32`, which is required by `i32: Foo`
|
help: this trait has no implementations, consider adding one
--> f100.rs:2:1
|
2 | trait Bar {}
| ^^^^^^^^^
note: required for `i32` to implement `Foo`
--> f100.rs:3:14
|
3 | impl<T: Bar> Foo for T {}
| --- ^^^ ^
| |
| unsatisfied trait bound introduced here
```
Fix#40120.
pattern_analysis: cleanup the contexts
This cleans up a bit the various `*Ctxt`s I had left lying around. As a bonus this made it possible to make `PatternColumn` public. I don't have a use for that yet but that could come useful.
`UsefulnessCtxt` looks useless right now but I'll be adding a field or two in subsequent PRs.
r? `````@compiler-errors`````
Further improve `space_between`
`space_between` is used by `print_tts` to decide when spaces should be put between tokens. This PR improves it in two ways:
- avoid unnecessary spaces before semicolons, and
- don't omit some necessary spaces before/after some punctuation symbols.
r? `@petrochenkov`
Disable packed/unpacked options for riscv linux/android.
Other riscv targets already only have the off option.
The packed/unpacked options might be supported in the future.
See upstream issue for more details:
https://github.com/llvm/llvm-project/issues/56642Fixes#110224
Expand the primary span of E0277 when the immediate unmet bound is not what the user wrote:
```
error[E0277]: the trait bound `i32: Bar` is not satisfied
--> f100.rs:6:6
|
6 | <i32 as Foo>::foo();
| ^^^ the trait `Bar` is not implemented for `i32`, which is required by `i32: Foo`
|
help: this trait has no implementations, consider adding one
--> f100.rs:2:1
|
2 | trait Bar {}
| ^^^^^^^^^
note: required for `i32` to implement `Foo`
--> f100.rs:3:14
|
3 | impl<T: Bar> Foo for T {}
| --- ^^^ ^
| |
| unsatisfied trait bound introduced here
```
Fix#40120.
`Diagnostic::keys`, which is used for hashing and equating diagnostics,
has a surprising behaviour: it ignores children, but only for lints.
This was added in #88493 to fix some duplicated diagnostics, but it
doesn't seem necessary any more.
This commit removes the special case and only four tests have changed
output, with additional errors. And those additional errors aren't
exact duplicates, they're just similar. For example, in
src/tools/clippy/tests/ui/same_name_method.rs we currently have this
error:
```
error: method's name is the same as an existing method in a trait
--> $DIR/same_name_method.rs:75:13
|
LL | fn foo() {}
| ^^^^^^^^^^^
|
note: existing `foo` defined here
--> $DIR/same_name_method.rs:79:9
|
LL | impl T1 for S {}
| ^^^^^^^^^^^^^^^^
```
and with this change we also get this error:
```
error: method's name is the same as an existing method in a trait
--> $DIR/same_name_method.rs:75:13
|
LL | fn foo() {}
| ^^^^^^^^^^^
|
note: existing `foo` defined here
--> $DIR/same_name_method.rs:81:9
|
LL | impl T2 for S {}
| ^^^^^^^^^^^^^^^^
```
I think printing this second argument is reasonable, possibly even
preferable to hiding it. And the other cases are similar.
When a method not found on a type parameter could have been provided by any
of multiple traits, suggest each trait individually, instead of a single
suggestion to restrict the type parameter with *all* of them.
Before:
```
error[E0599]: the method `cmp` exists for reference `&T`, but its trait bounds were not satisfied
--> $DIR/method-on-unbounded-type-param.rs:5:10
|
LL | (&a).cmp(&b)
| ^^^ method cannot be called on `&T` due to unsatisfied trait bounds
|
= note: the following trait bounds were not satisfied:
`T: Ord`
which is required by `&T: Ord`
`&T: Iterator`
which is required by `&mut &T: Iterator`
`T: Iterator`
which is required by `&mut T: Iterator`
help: consider restricting the type parameters to satisfy the trait bounds
|
LL | fn g<T>(a: T, b: T) -> std::cmp::Ordering where T: Iterator, T: Ord {
| +++++++++++++++++++++++++
```
After:
```
error[E0599]: the method `cmp` exists for reference `&T`, but its trait bounds were not satisfied
--> $DIR/method-on-unbounded-type-param.rs:5:10
|
LL | (&a).cmp(&b)
| ^^^ method cannot be called on `&T` due to unsatisfied trait bounds
|
= note: the following trait bounds were not satisfied:
`T: Ord`
which is required by `&T: Ord`
`&T: Iterator`
which is required by `&mut &T: Iterator`
`T: Iterator`
which is required by `&mut T: Iterator`
= help: items from traits can only be used if the type parameter is bounded by the trait
help: the following traits define an item `cmp`, perhaps you need to restrict type parameter `T` with one of them:
|
LL | fn g<T: Ord>(a: T, b: T) -> std::cmp::Ordering {
| +++++
LL | fn g<T: Iterator>(a: T, b: T) -> std::cmp::Ordering {
| ++++++++++
```
Fix#108428.
Normalize region obligation in lexical region resolution with next-gen solver
This normalizes region obligations when we `resolve_regions`, since they may be unnormalized with deferred projection equality.
It's pretty hard to add tests that exercise this without also triggering MIR borrowck errors (because we don't normalize there yet). I've added one test with two revisions that should test that we both 1. normalize region obligations in the param env, and 2. normalize registered region obligations during lexical region resolution.
When encountering
```rust
fn f<T>(a: T, b: T) -> std::cmp::Ordering {
a.cmp(&b) //~ ERROR E0599
}
```
output
```
error[E0599]: no method named `cmp` found for type parameter `T` in the current scope
--> $DIR/method-on-unbounded-type-param.rs:2:7
|
LL | fn f<T>(a: T, b: T) -> std::cmp::Ordering {
| - method `cmp` not found for this type parameter
LL | a.cmp(&b)
| ^^^ method cannot be called on `T` due to unsatisfied trait bounds
|
= help: items from traits can only be used if the type parameter is bounded by the trait
help: the following traits define an item `cmp`, perhaps you need to restrict type parameter `T` with one of them:
|
LL | fn f<T: Ord>(a: T, b: T) -> std::cmp::Ordering {
| +++++
LL | fn f<T: Iterator>(a: T, b: T) -> std::cmp::Ordering {
| ++++++++++
```
Fix#120186.
Remove some unnecessary check logic for lang items in HIR typeck
Obvious bugs with `#[no_core]` do not deserve customized recovery logic, since they are bugs we do not expect users to ever encounter, and if users are experimenting with `#[no_core]`, they should really be familiar with the compiler implementation.
These error recoveries are implemented now only where issues have been reported in the past, rather than systematically validating lang items.
See https://github.com/rust-lang/compiler-team/issues/620
> In particular, one-off fixes for particular assumptions about lang items or intrinsics that introduce additional complexity into the compiler are not accepted.
r? Nilstrieb
Improve error message when `cargo build` is used to build the compiler
Inspired by #76446.
Doing it for `core` is probably higher value but also way harder because tools like cargo or rustc-build-sysroot would need to be fixed first, which I don't feel like doing.
Revert outdated version of "Add the wasm32-wasi-preview2 target"
An outdated version of #119616 was merged in rollup #120309.
This reverts those changes to enable #119616 to “retain the intended diff” after a rebase.
```@rylev``` has agreed that this would be the cleanest approach with respect to the history.
Unblocks #119616.
r? ```@petrochenkov``` or compiler or libs
Remove various `has_errors` or `err_count` uses
follow up to https://github.com/rust-lang/rust/pull/119895
r? `@nnethercote` since you recently did something similar.
There are so many more of these, but I wanted to get a PR out instead of growing the commit list indefinitely. The commits all work on their own and can be reviewed commit by commit.
Deduplicate more sized errors on call exprs
Change the implicit `Sized` `Obligation` `Span` for call expressions to include the whole expression. This aids the existing deduplication machinery to reduce the number of errors caused by a single unsized expression.
Suppress unhelpful diagnostics for unresolved top level attributes
Fixes#118455, unresolved top level attribute error didn't imported prelude and already have emitted an error, report builtin macro and attributes error by the way, so `check_invalid_crate_level_attr` in can ignore them.
Also fixes#89566, fixes#67107.
r? `@petrochenkov`
The query accept arbitrary DefIds, not just owner DefIds.
The return can be an `Option` because if there are no nodes, then it doesn't matter whether it's due to NonOwner or Phantom.
Also rename the query to `opt_hir_owner_nodes`.
Be more careful about interpreting a label/lifetime as a mistyped char literal.
Currently the parser interprets any label/lifetime in certain positions as a mistyped char literal, on the assumption that the trailing single quote was accidentally omitted. In such cases it gives an error with a suggestion to add the trailing single quote, and then puts the appropriate char literal into the AST. This behaviour was introduced in #101293.
This is reasonable for a case like this:
```
let c = 'a;
```
because `'a'` is a valid char literal. It's less reasonable for a case like this:
```
let c = 'abc;
```
because `'abc'` is not a valid char literal.
Prior to #120329 this could result in some sub-optimal suggestions in error messages, but nothing else. But #120329 changed `LitKind::from_token_lit` to assume that the char/byte/string literals it receives are valid, and to assert if not. This is reasonable because the lexer does not produce invalid char/byte/string literals in general. But in this "interpret label/lifetime as unclosed char literal" case the parser can produce an invalid char literal with contents such as `abc`, which triggers an assertion failure.
This PR changes the parser so it's more cautious about interpreting labels/lifetimes as unclosed char literals.
Fixes#120397.
r? `@compiler-errors`
Fixes footnote handling in rustdoc
Fixes#100638.
You can now declare footnotes like this:
```rust
//! Reference to footnotes A[^1], B[^2] and C[^3].
//!
//! [^1]: Footnote A.
//! [^2]: Footnote B.
//! [^3]: Footnote C.
```
r? `@notriddle`
Make the coroutine def id of an async closure the child of the closure def id
Adjust def collection to make the (inner) coroutine returned by an async closure be a def id child of the (outer) closure. This makes it easy to map from coroutine -> closure by using `tcx.parent`, since currently it's not trivial to do this.
Because it's almost always static.
This makes `impl IntoDiagnosticArg for DiagnosticArgValue` trivial,
which is nice.
There are a few diagnostics constructed in
`compiler/rustc_mir_build/src/check_unsafety.rs` and
`compiler/rustc_mir_transform/src/errors.rs` that now need symbols
converted to `String` with `to_string` instead of `&str` with `as_str`,
but that' no big deal, and worth it for the simplifications elsewhere.
only assemble alias bound candidates for rigid aliases
fixes https://github.com/rust-lang/trait-system-refactor-initiative/issues/77
This also causes `<Wrapper<?0> as Trait>::Unwrap: Trait` to always be ambig, as we now normalize the self type before checking whether it is an inference variable.
I cannot think of an approach to the underlying issues here which does not require the "may-define means must-define" restriction for opaque types. Going to go ahead with this and added this restriction to the tracking issue for the new solver to make sure we don't stabilize it without getting types + lang signoff here.
r? `@compiler-errors`
Do not attempt to provide an accurate suggestion for `impl Trait`
in bare trait types when linting. Instead, only do the object
safety check when an E0782 is already going to be emitted in the
2021 edition.
Fix#120241.
Borrow check inline const patterns
Add type annotations to MIR so that borrowck can pass constraints from inline constants in patterns to the containing function.
Also enables some inline constant pattern tests that were fixed by the THIR unsafeck stabilization.
cc #76001
Improve handling of expressions in patterns
Closes#112593.
Methodcalls' dots in patterns are silently recovered as commas (e.g. `Foo("".len())` -> `Foo("", len())`) so extra diagnostics are emitted:
```rs
struct Foo(u8, String, u8);
fn bar(foo: Foo) -> bool {
match foo {
Foo(4, "yippee".yeet(), 7) => true,
_ => false
}
}
```
```
error: expected one of `)`, `,`, `...`, `..=`, `..`, or `|`, found `.`
--> main.rs:5:24
|
5 | Foo(4, "yippee".yeet(), 7) => true,
| ^
| |
| expected one of `)`, `,`, `...`, `..=`, `..`, or `|`
| help: missing `,`
error[E0531]: cannot find tuple struct or tuple variant `yeet` in this scope
--> main.rs:5:25
|
5 | Foo(4, "yippee".yeet(), 7) => true,
| ^^^^ not found in this scope
error[E0023]: this pattern has 4 fields, but the corresponding tuple struct has 3 fields
--> main.rs:5:13
|
1 | struct Foo(u8, String, u8);
| -- ------ -- tuple struct has 3 fields
...
5 | Foo(4, "yippee".yeet(), 7) => true,
| ^ ^^^^^^^^ ^^^^^^ ^ expected 3 fields, found 4
error: aborting due to 3 previous errors
```
This PR checks for patterns that ends with a dot and a lowercase ident (as structs/variants should be uppercase):
```
error: expected a pattern, found a method call
--> main.rs:5:16
|
5 | Foo(4, "yippee".yeet(), 7) => true,
| ^^^^^^^^^^^^^^^ method calls are not allowed in patterns
error: aborting due to 1 previous error
```
Also check for expressions:
```rs
fn is_idempotent(x: f32) -> bool {
match x {
x * x => true,
_ => false,
}
}
fn main() {
let mut t: [i32; 5];
let t[0] = 1;
}
```
```
error: expected a pattern, found an expression
--> main.rs:3:9
|
3 | x * x => true,
| ^^^^^ arbitrary expressions are not allowed in patterns
error: expected a pattern, found an expression
--> main.rs:10:9
|
10 | let t[0] = 1;
| ^^^^ arbitrary expressions are not allowed in patterns
```
Would be cool if the compiler could suggest adding a guard for `match`es, but I've no idea how to do it.
---
`@rustbot` label +A-diagnostics +A-parser +A-patterns +C-enhancement
Currently the parser will interpret any label/lifetime in certain
positions as a mistyped char literal, on the assumption that the
trailing single quote was accidentally omitted. This is reasonable for a
something like 'a (because 'a' would be valid) but not reasonable for a
something like 'abc (because 'abc' is not valid).
This commit restricts this behaviour only to labels/lifetimes that would
be valid char literals, via the new `could_be_unclosed_char_literal`
function. The commit also augments the `label-is-actually-char.rs` test
in a couple of ways:
- Adds testing of labels/lifetimes with identifiers longer than one
char, e.g. 'abc.
- Adds a new match with simpler patterns, because the
`recover_unclosed_char` call in `parse_pat_with_range_pat` was not
being exercised (in this test or any other ui tests).
Fixes#120397, an assertion failure, which was caused by this behaviour
in the parser interacting with some new stricter char literal checking
added in #120329.
Error codes are integers, but `String` is used everywhere to represent
them. Gross!
This commit introduces `ErrCode`, an integral newtype for error codes,
replacing `String`. It also introduces a constant for every error code,
e.g. `E0123`, and removes the `error_code!` macro. The constants are
imported wherever used with `use rustc_errors::codes::*`.
With the old code, we have three different ways to specify an error code
at a use point:
```
error_code!(E0123) // macro call
struct_span_code_err!(dcx, span, E0123, "msg"); // bare ident arg to macro call
\#[diag(name, code = "E0123")] // string
struct Diag;
```
With the new code, they all use the `E0123` constant.
```
E0123 // constant
struct_span_code_err!(dcx, span, E0123, "msg"); // constant
\#[diag(name, code = E0123)] // constant
struct Diag;
```
The commit also changes the structure of the error code definitions:
- `rustc_error_codes` now just defines a higher-order macro listing the
used error codes and nothing else.
- Because that's now the only thing in the `rustc_error_codes` crate, I
moved it into the `lib.rs` file and removed the `error_codes.rs` file.
- `rustc_errors` uses that macro to define everything, e.g. the error
code constants and the `DIAGNOSTIC_TABLES`. This is in its new
`codes.rs` file.
This makes no sense, and has no effect. I suspect it's been confused
with a `code = "{code}"` attribute on a subdiagnostic suggestion, where
it is valid (but the "code" there is suggested source code, rather than
an error code.)
Merge into larger interval set
This reduces the work done while merging rows. In at least one case (#50450), we have thousands of union([range], [20,000 ranges]), which previously inserted each of the 20,000 ranges one by one. Now we only insert one range into the right hand set after copying the set over.
This cuts the runtime of the test case in #50450 from ~26 seconds to ~6 seconds locally, though it doesn't change the memory usage peak (~9.5GB).
llvm: change data layout bug to an error and make it trigger more
Fixes#33446.
Don't skip the inconsistent data layout check for custom LLVMs or non-built-in targets.
With #118708, all targets will have a simple test that would trigger this error if LLVM's data layouts do change - so data layouts would be corrected during the LLVM upgrade. Therefore, with builtin targets, this error won't happen with our LLVM because each target will have been confirmed to work. With non-builtin targets, this error is probably useful to have because you can change the data layout in your target and if it is wrong then that could lead to bugs.
When using a custom LLVM, the same justification makes sense for non-builtin targets as with our LLVM, the user can update their target to match their LLVM and that's probably a good thing to do. However, with a custom LLVM, the user cannot change the builtin target data layouts if they don't match - though given that the compiler's data layout is used for layout computation and a bunch of other things - you could get some bugs because of the mismatch and probably want to know about that. I'm not sure if this is something that people do and is okay, but I doubt it?
`CFG_LLVM_ROOT` was also always set during local development with `download-ci-llvm` so this bug would never trigger locally.
In #33446, two points are raised:
- In the issue itself, changing this from a `bug!` to a proper error is what is suggested, by using `isCompatibleDataLayout` from LLVM, but that function still just does the same thing that we do and check for equality, so I've avoided the additional code necessary to do that FFI call.
- `@Mark-Simulacrum` suggests a different check is necessary to maintain backwards compatibility with old LLVM versions. I don't know how often this comes up, but we can do that with some simple string manipulation + LLVM version checks as happens already for LLVM 17 just above this diff.
Improve handling of numbers in `IntoDiagnosticArg`
While working on https://github.com/rust-lang/rust/pull/120393, I realize that my fluent selectors were not working. So here is an improvement (not a fix unfortunately).
ScopeTree: remove destruction_scopes as unused
last usages removed by https://github.com/rust-lang/rust/pull/116170
Unused, but still presented in memory at `t-gmax` (in DHAT termonology)
Properly recover from trailing attr in body
When encountering an attribute in a body, we try to recover from an attribute on an expression (as opposed to a statement). We need to properly clean up when the attribute is at the end of the body where a tail expression would be.
Fix#118164, fix#118575.
Add the unstable option to reduce the binary size of dynamic library…
# Motivation
The average length of symbol names in the rust standard library is about 100 bytes, while the average length of symbol names in the C++ standard library is about 65 bytes. In some embedded environments where dynamic library are widely used, rust dynamic library symbol name space hash become one of the key bottlenecks of application, Especially when the existing C/C++ module is reconstructed into the rust module.
The unstable option `-Z symbol_mangling_version=hashed` is added to solve the bottleneck caused by too long dynamic library symbol names.
## Test data
The following is a set of test data on the ubuntu 18.04 LTS environment. With this plug-in, the space saving rate of dynamic libraries can reach about 20%.
The test object is the standard library of rust (built based on Xargo), tokio crate, and hyper crate.
The contents of the Cargo.toml file in the construction project of the three dynamic libraries are as follows:
```txt
# Cargo.toml
[profile.release]
panic = "abort"
opt-leve="z"
codegen-units=1
strip=true
debug=true
```
The built dynamic library also removes the `.rustc` segments that are not needed at run time and then compares the size. The detailed data is as follows:
1. libstd.so
> | symbol_mangling_version | size | saving rate |
> | --- | --- | --- |
> | legacy | 804896 ||
> | hashed | 608288 | 0.244 |
> | v0 | 858144 ||
> | hashed | 608288 | 0.291 |
2. libhyper.so
> | symbol_mangling_version(libhyper.so) | symbol_mangling_version(libstd.so) | size | saving rate |
> | --- | --- | --- | --- |
> | legacy | legacy | 866312 ||
> | hashed | legacy | 645128 |0.255|
> | legacy | hashed | 854024 ||
> | hashed | hashed | 632840 |0.259|
When encountering an attribute in a body, we try to recover from an
attribute on an expression (as opposed to a statement). We need to
properly clean up when the attribute is at the end of the body where a
tail expression would be.
Fix#118164.
Classify closure arguments in refutable pattern in argument error
You can call it a function (and people may or may not agree with that), but it's better to just say those are closure arguments instead.
Normalize field types before checking validity
I forgot to normalize field types when checking ADT-like aggregates in the MIR validator.
This normalization is needed due to a crude check for opaque types in `mir_assign_valid_types` which prevents opaque type cycles -- if we pass in an unnormalized type, we may not detect that the destination type is an opaque, and therefore will call `type_of(opaque)` later on, which causes a cycle error -> ICE.
Fixes#120253
Rename `pointer` field on `Pin`
A few days ago, I was helping another user create a self-referential type using `PhantomPinned`. However, I noticed an odd behavior when I tried to access one of the type's fields via `Pin`'s `Deref` impl:
```rust
use std::{marker::PhantomPinned, ptr};
struct Pinned {
data: i32,
pointer: *const i32,
_pin: PhantomPinned,
}
fn main() {
let mut b = Box::pin(Pinned {
data: 42,
pointer: ptr::null(),
_pin: PhantomPinned,
});
{
let pinned = unsafe { b.as_mut().get_unchecked_mut() };
pinned.pointer = &pinned.data;
}
println!("{}", unsafe { *b.pointer });
}
```
```rust
error[E0658]: use of unstable library feature 'unsafe_pin_internals'
--> <source>:19:30
|
19 | println!("{}", unsafe { *b.pointer });
| ^^^^^^^^^
error[E0277]: `Pinned` doesn't implement `std::fmt::Display`
--> <source>:19:20
|
19 | println!("{}", unsafe { *b.pointer });
| ^^^^^^^^^^^^^^^^^^^^^ `Pinned` cannot be formatted with the default formatter
|
= help: the trait `std::fmt::Display` is not implemented for `Pinned`
= note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
= note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
```
Since the user named their field `pointer`, it conflicts with the `pointer` field on `Pin`, which is public but unstable since Rust 1.60.0 with #93176. On versions from 1.33.0 to 1.59.0, where the field on `Pin` is private, this program compiles and prints `42` as expected.
To avoid this confusing behavior, this PR renames `pointer` to `__pointer`, so that it's less likely to conflict with a `pointer` field on the underlying type, as accessed through the `Deref` impl. This is technically a breaking change for anyone who names their field `__pointer` on the inner type; if this is undesirable, it could be renamed to something more longwinded. It's also a nightly breaking change for any external users of `unsafe_pin_internals`.
Don't fire `OPAQUE_HIDDEN_INFERRED_BOUND` on sized return of AFIT
Conceptually, we should probably not fire `OPAQUE_HIDDEN_INFERRED_BOUND` for methods like:
```
trait Foo { async fn bar() -> Self; }
```
Even though we technically cannot prove that `Self: Sized`, which is one of the item bounds of the `Output` type in the `-> impl Future<Output = Sized>` from the async desugaring.
This is somewhat justifiable along the same lines as how we allow regular methods to return `-> Self` even though `Self` isn't sized.
Fixes#113538
(side-note: some days i wonder if we should just remove the `OPAQUE_HIDDEN_INFERRED_BOUND` lint... it does make me sad that we have non-well-formed types in signatures, though.)
privacy: Refactor top-level visiting in `NamePrivacyVisitor`
Full hierarchical visiting (`nested_filter::All`) is not necessary, visiting all item-likes in isolation is enough.
Tracking current item is not necessary, passing any `HirId` with the same parent module to `adjust_ident_and_get_scope` is enough.
Follow up to https://github.com/rust-lang/rust/pull/120284.
interpret: project_downcast: do not ICE for uninhabited variants
Fixes https://github.com/rust-lang/rust/issues/120337
This assertion was already under discussion for a bit; I think the [example](https://github.com/rust-lang/rust/issues/120337#issuecomment-1911076292) `@tmiasko` found is the final nail in the coffin. One could argue maybe MIR building should read the discriminant before projecting, but even then MIR optimizations should be allowed to remove that read, so the downcast should still not ICE. Maybe the downcast should be UB, but in this example UB already arises earlier when a value of type `E` is constructed.
r? `@oli-obk`
Don't manually resolve async closures in `rustc_resolve`
There's a comment here that talks about doing this "[so] closure [args] are detected as upvars rather than normal closure arg usages", but we do upvar analysis on the HIR now:
cd6d8f2a04/compiler/rustc_passes/src/upvars.rs (L21-L29)
Removing this ad-hoc logic makes it so that `async |x: &str|` now introduces an implicit binder, like regular closures.
r? ```@oli-obk```
Builtin macros effectively have implicit #[collapse_debuginfo(yes)]
If collapse_debuginfo attribute for builtin macro is not specified explicitly, it will be effectively set to `#[collapse_debuginfo(yes)]`.
Add the `min_exhaustive_patterns` feature gate
## Motivation
Pattern-matching on empty types is tricky around unsafe code. For that reason, current stable rust conservatively requires arms for empty types in all but the simplest case. It has long been the intention to allow omitting empty arms when it's safe to do so. The [`exhaustive_patterns`](https://github.com/rust-lang/rust/issues/51085) feature allows the omission of all empty arms, but hasn't been stabilized because that was deemed dangerous around unsafe code.
## Proposal
This feature aims to stabilize an uncontroversial subset of exhaustive_patterns. Namely: when `min_exhaustive_patterns` is enabled and the data we're matching on is guaranteed to be valid by rust's operational semantics, then we allow empty arms to be omitted. E.g.:
```rust
let x: Result<T, !> = foo();
match x { // ok
Ok(y) => ...,
}
let Ok(y) = x; // ok
```
If the place is not guaranteed to hold valid data (namely ptr dereferences, ref dereferences (conservatively) and union field accesses), then we keep stable behavior i.e. we (usually) require arms for the empty cases.
```rust
unsafe {
let ptr: *const Result<u32, !> = ...;
match *ptr {
Ok(x) => { ... }
Err(_) => { ... } // still required
}
}
let foo: Result<u32, &!> = ...;
match foo {
Ok(x) => { ... }
Err(&_) => { ... } // still required because of the dereference
}
unsafe {
let ptr: *const ! = ...;
match *ptr {} // already allowed on stable
}
```
Note that we conservatively consider that a valid reference can point to invalid data, hence we don't allow arms of type `&!` and similar cases to be omitted. This could eventually change depending on [opsem decisions](https://github.com/rust-lang/unsafe-code-guidelines/issues/413). Whenever opsem is undecided on a case, we conservatively keep today's stable behavior.
I proposed this behavior in the [`never_patterns`](https://github.com/rust-lang/rust/issues/118155) feature gate but it makes sense on its own and could be stabilized more quickly. The two proposals nicely complement each other.
## Unresolved Questions
Part of the question is whether this requires an RFC. I'd argue this doesn't need one since there is no design question beyond the intent to omit unreachable patterns, but I'm aware the problem can be framed in ways that require design (I'm thinking of the [original never patterns proposal](https://smallcultfollowing.com/babysteps/blog/2018/08/13/never-patterns-exhaustive-matching-and-uninhabited-types-oh-my/), which would frame this behavior as "auto-nevering" happening).
EDIT: I initially proposed a future-compatibility lint as part of this feature, I don't anymore.
Remove unused/unnecessary features
~~The bulk of the actual code changes here is replacing try blocks with equivalent closures. I'm not entirely sure that's a good idea since it may have perf impact, happy to revert if that's the case/the change is unwanted.~~
I also removed a lot of `recursion_limit = "256"` since everything seems to build fine without that and most don't have any comment justifying it.
remove StructuralEq trait
The documentation given for the trait is outdated: *all* function pointers implement `PartialEq` and `Eq` these days. So the `StructuralEq` trait doesn't really seem to have any reason to exist any more.
One side-effect of this PR is that we allow matching on some consts that do not implement `Eq`. However, we already allowed matching on floats and consts containing floats, so this is not new, it is just allowed in more cases now. IMO it makes no sense at all to allow float matching but also sometimes require an `Eq` instance. If we want to require `Eq` we should adjust https://github.com/rust-lang/rust/pull/115893 to check for `Eq`, and rule out float matching for good.
Fixes https://github.com/rust-lang/rust/issues/115881
Remove coroutine info when building coroutine drop body
Coroutine drop shims are not themselves coroutines, so erase the "`coroutine`" field from the body so that helper fns like `yield_ty` and `coroutine_kind` properly return `None` for the drop shim.
Don't call `walk_` functions directly if there is an equivalent `visit_` method
I was working on https://github.com/rust-lang/rust/issues/77773 and realized in one of my experiments that the `visit_path` method was not always called whereas it should have. This fixes it.
r? ``@davidtwco``
linker: Refactor library linking methods in `trait Linker`
Linkers are not aware of Rust libraries, they look like regular static or dynamic libraries to them, so Rust-specific methods in `trait Linker` do not make much sense.
They can be either removed or renamed to something more suitable.
Commits after the second one are cleanups.
Rollup of 10 pull requests
Successful merges:
- #119305 (Add `AsyncFn` family of traits)
- #119389 (Provide more context on recursive `impl` evaluation overflow)
- #119895 (Remove `track_errors` entirely)
- #120230 (Assert that a single scope is passed to `for_scope`)
- #120278 (Remove --fatal-warnings on wasm targets)
- #120292 (coverage: Dismantle `Instrumentor` and flatten span refinement)
- #120315 (On E0308 involving `dyn Trait`, mention trait objects)
- #120317 (pattern_analysis: Let `ctor_sub_tys` return any Iterator they want)
- #120318 (pattern_analysis: Reuse most of the `DeconstructedPat` `Debug` impl)
- #120325 (rustc_data_structures: use either instead of itertools)
r? `@ghost`
`@rustbot` modify labels: rollup
rustc_data_structures: use either instead of itertools
`itertools::Either` is a re-export from `either`, so we might as well use the source.
This flattens the compiler build tree a little, but I don't really expect it to make much difference overall.
pattern_analysis: Reuse most of the `DeconstructedPat` `Debug` impl
The `DeconstructedPat: Debug` is best-effort because we'd need `tcx` to get things like field names etc. Since rust-analyzer has a similar constraint, this PR moves most the impl to be shared between the two. While I was at it I also fixed a nit in the `IntRange: Debug` impl.
r? `@compiler-errors`
pattern_analysis: Let `ctor_sub_tys` return any Iterator they want
I noticed that we always `.cloned()` and allocate the output of `TypeCx::ctor_sub_tys` now, so there was no need to force it to return a slice. `ExactSizeIterator` is not super important but saves some manual counting.
r? `@compiler-errors`
On E0308 involving `dyn Trait`, mention trait objects
When encountering a type mismatch error involving `dyn Trait`, mention the existence of boxed trait objects if the other type involved implements `Trait`.
Fix#102629.
coverage: Dismantle `Instrumentor` and flatten span refinement
This is a combination of two refactorings that are unrelated, but would otherwise have a merge conflict.
No functional changes, other than a small tweak to debug logging as part of rearranging some functions.
Ignoring whitespace is highly recommended, since most of the modified lines have just been reindented.
---
The first change is to dismantle `Instrumentor` into ordinary functions.
This is one of those cases where encapsulating several values into a struct ultimately hurts more than it helps. With everything stored as local variables in one main function, and passed explicitly into helper functions, it's easier to see what is used where, and make changes as necessary.
---
The second change is to flatten the functions for extracting/refining coverage spans.
Consolidating this code into flatter functions reduces the amount of pointer-chasing required to read and modify it.
Remove --fatal-warnings on wasm targets
These were added with good intentions, but a recent change in LLVM 18 emits a warning while examining .rmeta sections in .rlib files. Since this flag is a nice-to-have and users can update their LLVM linker independently of rustc's LLVM version, we can just omit the flag.
See [this comment on wasm targets' uses of `--fatal-warnings`](https://github.com/llvm/llvm-project/pull/78658#issuecomment-1906651390).
Remove `track_errors` entirely
follow up to https://github.com/rust-lang/rust/pull/119869
r? `@matthewjasper`
There are some diagnostic changes adding new diagnostics or not emitting some anymore. We can improve upon that in follow-up work imo.
Provide more context on recursive `impl` evaluation overflow
When an associated type `Self::Assoc` is part of a `where` clause, we end up unable to evaluate the requirement and emit a E0275.
We now point at the associated type if specified in the `impl`. If so, we also suggest using that type instead of `Self::Assoc`. Otherwise, we explain that these are not allowed.
```
error[E0275]: overflow evaluating the requirement `<(T,) as Grault>::A == _`
--> $DIR/impl-wf-cycle-1.rs:15:1
|
LL | / impl<T: Grault> Grault for (T,)
LL | |
LL | | where
LL | | Self::A: Baz,
LL | | Self::B: Fiz,
| |_________________^
LL | {
LL | type A = ();
| ------ associated type `<(T,) as Grault>::A` is specified here
|
note: required for `(T,)` to implement `Grault`
--> $DIR/impl-wf-cycle-1.rs:15:17
|
LL | impl<T: Grault> Grault for (T,)
| ^^^^^^ ^^^^
...
LL | Self::A: Baz,
| --- unsatisfied trait bound introduced here
= note: 1 redundant requirement hidden
= note: required for `(T,)` to implement `Grault`
help: associated type for the current `impl` cannot be restricted in `where` clauses, remove this bound
|
LL - Self::A: Baz,
|
```
```
error[E0275]: overflow evaluating the requirement `<T as B>::Type == <T as B>::Type`
--> $DIR/impl-wf-cycle-3.rs:7:1
|
LL | / impl<T> B for T
LL | | where
LL | | T: A<Self::Type>,
| |_____________________^
LL | {
LL | type Type = bool;
| --------- associated type `<T as B>::Type` is specified here
|
note: required for `T` to implement `B`
--> $DIR/impl-wf-cycle-3.rs:7:9
|
LL | impl<T> B for T
| ^ ^
LL | where
LL | T: A<Self::Type>,
| ------------- unsatisfied trait bound introduced here
help: replace the associated type with the type specified in this `impl`
|
LL | T: A<bool>,
| ~~~~
```
```
error[E0275]: overflow evaluating the requirement `<T as Filter>::ToMatch == <T as Filter>::ToMatch`
--> $DIR/impl-wf-cycle-4.rs:5:1
|
LL | / impl<T> Filter for T
LL | | where
LL | | T: Fn(Self::ToMatch),
| |_________________________^
|
note: required for `T` to implement `Filter`
--> $DIR/impl-wf-cycle-4.rs:5:9
|
LL | impl<T> Filter for T
| ^^^^^^ ^
LL | where
LL | T: Fn(Self::ToMatch),
| ----------------- unsatisfied trait bound introduced here
note: associated types for the current `impl` cannot be restricted in `where` clauses
--> $DIR/impl-wf-cycle-4.rs:7:11
|
LL | T: Fn(Self::ToMatch),
| ^^^^^^^^^^^^^
```
Fix#116925
Add `AsyncFn` family of traits
I'm proposing to add a new family of `async`hronous `Fn`-like traits to the standard library for experimentation purposes.
## Why do we need new traits?
On the user side, it is useful to be able to express `AsyncFn` trait bounds natively via the parenthesized sugar syntax, i.e. `x: impl AsyncFn(&str) -> String` when experimenting with async-closure code.
This also does not preclude `AsyncFn` becoming something else like a trait alias if a more fundamental desugaring (which can take many[^1] different[^2] forms) comes around. I think we should be able to play around with `AsyncFn` well before that, though.
I'm also not proposing stabilization of these trait names any time soon (we may even want to instead express them via new syntax, like `async Fn() -> ..`), but I also don't think we need to introduce an obtuse bikeshedding name, since `AsyncFn` just makes sense.
## The lending problem: why not add a more fundamental primitive of `LendingFn`/`LendingFnMut`?
Firstly, for `async` closures to be as flexible as possible, they must be allowed to return futures which borrow from the async closure's captures. This can be done by introducing `LendingFn`/`LendingFnMut` traits, or (equivalently) by adding a new generic associated type to `FnMut` which allows the return type to capture lifetimes from the `&mut self` argument of the trait. This was proposed in one of [Niko's blog posts](https://smallcultfollowing.com/babysteps/blog/2023/05/09/giving-lending-and-async-closures/).
Upon further experimentation, for the purposes of closure type- and borrow-checking, I've come to the conclusion that it's significantly harder to teach the compiler how to handle *general* lending closures which may borrow from their captures. This is, because unlike `Fn`/`FnMut`, the `LendingFn`/`LendingFnMut` traits don't form a simple "inheritance" hierarchy whose top trait is `FnOnce`.
```mermaid
flowchart LR
Fn
FnMut
FnOnce
LendingFn
LendingFnMut
Fn -- isa --> FnMut
FnMut -- isa --> FnOnce
LendingFn -- isa --> LendingFnMut
Fn -- isa --> LendingFn
FnMut -- isa --> LendingFnMut
```
For example:
```
fn main() {
let s = String::from("hello, world");
let f = move || &s;
let x = f(); // This borrows `f` for some lifetime `'1` and returns `&'1 String`.
```
That trait hierarchy means that in general for "lending" closures, like `f` above, there's not really a meaningful return type for `<typeof(f) as FnOnce>::Output` -- it can't return `&'static str`, for example.
### Special-casing this problem:
By splitting out these traits manually, and making sure that each trait has its own associated future type, we side-step the issue of having to answer the questions of a general `LendingFn`/`LendingFnMut` implementation, since the compiler knows how to generate built-in implementations for first-class constructs like async closures, including the required future types for the (by-move) `AsyncFnOnce` and (by-ref) `AsyncFnMut`/`AsyncFn` trait implementations.
[^1]: For example, with trait transformers, we may eventually be able to write: `trait AsyncFn = async Fn;`
[^2]: For example, via the introduction of a more fundamental "`LendingFn`" trait, plus a [special desugaring with augmented trait aliases](https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/Lending.20closures.20and.20Fn*.28.29.20-.3E.20impl.20Trait/near/408471480).
Modify GenericArg and Term structs to use strict provenance rules
This is the first PR to solve issue #119217 . In this PR, I have modified the GenericArg struct to use the `NonNull` struct as the pointer instead of `NonZeroUsize`. The change were tested by running `./x test compiler/rustc_middle`.
Resolves https://github.com/rust-lang/rust/issues/119217
r? `@WaffleLapkin`
Replacement of #114390: Add new intrinsic `is_var_statically_known` and optimize pow for powers of two
This adds a new intrinsic `is_val_statically_known` that lowers to [``@llvm.is.constant.*`](https://llvm.org/docs/LangRef.html#llvm-is-constant-intrinsic).` It also applies the intrinsic in the int_pow methods to recognize and optimize the idiom `2isize.pow(x)`. See #114390 for more discussion.
While I have extended the scope of the power of two optimization from #114390, I haven't added any new uses for the intrinsic. That can be done in later pull requests.
Note: When testing or using the library, be sure to use `--stage 1` or higher. Otherwise, the intrinsic will be a noop and the doctests will be skipped. If you are trying out edits, you may be interested in [`--keep-stage 0`](https://rustc-dev-guide.rust-lang.org/building/suggested.html#faster-builds-with---keep-stage).
Fixes#47234Resolves#114390
`@Centri3`
Remove all ConstPropNonsense
We track all locals and projections on them ourselves within the const propagator and only use the InterpCx to actually do some low level operations or read from constants (via `OpTy` we get for said constants).
This helps moving the const prop lint out from the normal pipeline and running it just based on borrowck information. This in turn allows us to make progress on https://github.com/rust-lang/rust/pull/108730#issuecomment-1875557745
there are various follow up cleanups that can be done after this PR (e.g. not matching on Rvalue twice and doing binop checks twice), but lets try landing this one first.
r? `@RalfJung`
They can't contain `\x` escapes, which means they can't contain high
bytes, which means we can used `unescape_unicode` instead of
`unescape_mixed` to unescape them. This avoids unnecessary used of
`MixedUnit`.
`unescape_literal` becomes `unescape_unicode`, and `unescape_c_string`
becomes `unescape_mixed`. Because rfc3349 will mean that C string
literals will no longer be the only mixed utf8 literals.
- Rename it as `MixedUnit`, because it will soon be used in more than
just C string literals.
- Change the `Byte` variant to `HighByte` and use it only for
`\x80`..`\xff` cases. This fixes the old inexactness where ASCII chars
could be encoded with either `Byte` or `Char`.
- Add useful comments.
- Remove `is_ascii`, in favour of `u8::is_ascii`.
The `T` type in these functions took me some time to understand, and I
find the explicit `T` in the use of `from` makes the code easier to
read, as does the `u8` annotation in `scan_escape`.
The parser already does a check-only unescaping which catches all
errors. So the checking done in `from_token_lit` never hits.
But literals causing warnings can still occur in `from_token_lit`. So
the commit changes `str-escape.rs` to use byte string literals and C
string literals as well, to give better coverage and ensure the new
assertions in `from_token_lit` are correct.
When encountering a type mismatch error involving `dyn Trait`, mention
the existence of boxed trait objects if the other type involved
implements `Trait`.
Partially addresses #102629.
privacy: Refactor top-level visiting in `TypePrivacyVisitor`
Full hierarchical visiting (`nested_filter::All`) is not necessary, visiting all item-likes in isolation is enough.
Tracking current item is not necessary, just keeping the current `mod` item is enough.
`visit_generic_arg` should behave like its default version, including checking types of const arguments.
Some comments, including FIXMEs, are also added.
Noticed while reading code to review https://github.com/rust-lang/rust/pull/113671.
r? ``@oli-obk``
coverage: Don't instrument `#[automatically_derived]` functions
This PR makes the coverage instrumentor detect and skip functions that have [`#[automatically_derived]`](https://doc.rust-lang.org/reference/attributes/derive.html#the-automatically_derived-attribute) on their enclosing impl block.
Most notably, this means that methods generated by built-in derives (e.g. `Clone`, `Debug`, `PartialEq`) are now ignored by coverage instrumentation, and won't appear as executed or not-executed in coverage reports.
This is a noticeable change in user-visible behaviour, but overall I think it's a net improvement. For example, we've had a few user requests for this sort of change (e.g. #105055, https://github.com/rust-lang/rust/issues/84605#issuecomment-1902069040), and I believe it's the behaviour that most users will expect/prefer by default.
It's possible to imagine situations where users would want to instrument these derived implementations, but I think it's OK to treat that as an opportunity to consider adding more fine-grained option flags to control the details of coverage instrumentation, while leaving this new behaviour as the default.
(Also note that while `-Cinstrument-coverage` is a stable feature, the exact details of coverage instrumentation are allowed to change. So we *can* make this change; the main question is whether we *should*.)
Fixes#105055.
Add a new `wasm32-wasi-preview2` target
This is the initial implementation of the MCP https://github.com/rust-lang/compiler-team/issues/694 creating a new tier 3 target `wasm32-wasi-preview2`. That MCP has been seconded and will most likely be approved in a little over a week from now. For more information on the need for this target, please read the [MCP](https://github.com/rust-lang/compiler-team/issues/694).
There is one aspect of this PR that will become insta-stable once these changes reach a stable compiler:
* A new `target_family` named `wasi` is introduced. This target family incorporates all wasi targets including `wasm32-wasi` and its derivative `wasm32-wasi-preview1-threads`. The difference between `target_family = wasi` and `target_os = wasi` will become much clearer when `wasm32-wasi` is renamed to `wasm32-wasi-preview1` and the `target_os` becomes `wasm32-wasi-preview1`. You can read about this target rename in [this MCP](https://github.com/rust-lang/compiler-team/issues/695) which has also been seconded and will hopefully be officially approved soon.
Additional technical details include:
* Both `std::sys::wasi_preview2` and `std::os::wasi_preview2` have been created and mostly use `#[path]` annotations on their submodules to reach into the existing `wasi` (soon to be `wasi_preview1`) modules. Over time the differences between `wasi_preview1` and `wasi_preview2` will grow and most like all `#[path]` based module aliases will fall away.
* Building `wasi-preview2` relies on a [`wasi-sdk`](https://github.com/WebAssembly/wasi-sdk) in the same way that `wasi-preview1` does (one must include a `wasi-root` path in the `Config.toml` pointing to sysroot included in the wasi-sdk). The target should build against [wasi-sdk v21](https://github.com/WebAssembly/wasi-sdk/releases/tag/wasi-sdk-21) without modifications. However, the wasi-sdk itself is growing [preview2 support](https://github.com/WebAssembly/wasi-sdk/pull/370) so this might shift rapidly. We will be following along quickly to make sure that building the target remains possible as the wasi-sdk changes.
* This requires a [patch to libc](https://github.com/rylev/rust-libc/tree/wasm32-wasi-preview2) that we'll need to land in conjunction with this change. Until that patch lands the target won't actually build.
coverage: Never emit improperly-ordered coverage regions
If we emit a coverage region that is improperly ordered (end < start), `llvm-cov` will fail with `coveragemap_error::malformed`, which is inconvenient for users and also very hard to debug.
Ideally we would fix the root causes of these situations, but they tend to occur in very obscure edge-case scenarios (often involving nested macros), and we don't always have a good MCVE to work from. So it makes sense to also have a catch-all check that will prevent improperly-ordered regions from ever being emitted.
---
This is mainly aimed at resolving #119453. We don't have a specific way to reproduce it, which is why I haven't been able to add a test case in this PR. But based on the information provided in that issue, this change seems likely to avoid the error in `llvm-cov`.
`````@rustbot````` label +A-code-coverage
Return a finite number of AllocIds per ConstAllocation in Miri
Before this, every evaluation of a const slice would produce a new AllocId. So in Miri, this program used to have unbounded memory use:
```rust
fn main() {
loop {
helper();
}
}
fn helper() {
"ouch";
}
```
Every trip around the loop creates a new AllocId which we need to keep track of a base address for. And the provenance GC can never clean up that AllocId -> u64 mapping, because the AllocId is for a const allocation which will never be deallocated.
So this PR moves the logic of producing an AllocId for a ConstAllocation to the Machine trait, and the implementation that Miri provides will only produce 16 AllocIds for each allocation. The cache is also keyed on the Instance that the const is evaluated in, so that equal consts evaluated in two functions will have disjoint base addresses.
r? RalfJung
Change the implicit `Sized` `Obligation` `Span` for call expressions to
include the whole expression. This aids the existing deduplication
machinery to reduce the number of errors caused by a single unsized
expression.
Rollup of 9 pull requests
Successful merges:
- #112806 (Small code improvements in `collect_intra_doc_links.rs`)
- #119766 (Split tait and impl trait in assoc items logic)
- #120139 (Do not normalize closure signature when building `FnOnce` shim)
- #120160 (Manually implement derived `NonZero` traits.)
- #120171 (Fix assume and assert in jump threading)
- #120183 (Add `#[coverage(off)]` to closures introduced by `#[test]` and `#[bench]`)
- #120195 (add several resolution test cases)
- #120259 (Split Diagnostics for Uncommon Codepoints: Add List to Display Characters Involved)
- #120261 (Provide structured suggestion to use trait objects in some cases of `if` arm type divergence)
r? `@ghost`
`@rustbot` modify labels: rollup
Provide structured suggestion to use trait objects in some cases of `if` arm type divergence
```
error[E0308]: `if` and `else` have incompatible types
--> $DIR/suggest-box-on-divergent-if-else-arms.rs:15:9
|
LL | let _ = if true {
| _____________-
LL | | Struct
| | ------ expected because of this
LL | | } else {
LL | | foo()
| | ^^^^^ expected `Struct`, found `Box<dyn Trait>`
LL | | };
| |_____- `if` and `else` have incompatible types
|
= note: expected struct `Struct`
found struct `Box<dyn Trait>`
help: `Struct` implements `Trait` so you can box it to coerce to the trait object `Box<dyn Trait>`
|
LL | Box::new(Struct)
| +++++++++ +
error[E0308]: `if` and `else` have incompatible types
--> $DIR/suggest-box-on-divergent-if-else-arms.rs:20:9
|
LL | let _ = if true {
| _____________-
LL | | foo()
| | ----- expected because of this
LL | | } else {
LL | | Struct
| | ^^^^^^ expected `Box<dyn Trait>`, found `Struct`
LL | | };
| |_____- `if` and `else` have incompatible types
|
= note: expected struct `Box<dyn Trait>`
found struct `Struct`
= note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html
help: store this in the heap by calling `Box::new`
|
LL | Box::new(Struct)
| +++++++++ +
error[E0308]: `if` and `else` have incompatible types
--> $DIR/suggest-box-on-divergent-if-else-arms.rs:25:9
|
LL | fn bar() -> impl Trait {
| ---------- the found opaque type
...
LL | let _ = if true {
| _____________-
LL | | Struct
| | ------ expected because of this
LL | | } else {
LL | | bar()
| | ^^^^^ expected `Struct`, found opaque type
LL | | };
| |_____- `if` and `else` have incompatible types
|
= note: expected struct `Struct`
found opaque type `impl Trait`
help: `Struct` implements `Trait` so you can box both arms and coerce to the trait object `Box<dyn Trait>`
|
LL ~ Box::new(Struct) as Box<dyn Trait>
LL | } else {
LL ~ Box::new(bar())
|
error[E0308]: `if` and `else` have incompatible types
--> $DIR/suggest-box-on-divergent-if-else-arms.rs:30:9
|
LL | fn bar() -> impl Trait {
| ---------- the expected opaque type
...
LL | let _ = if true {
| _____________-
LL | | bar()
| | ----- expected because of this
LL | | } else {
LL | | Struct
| | ^^^^^^ expected opaque type, found `Struct`
LL | | };
| |_____- `if` and `else` have incompatible types
|
= note: expected opaque type `impl Trait`
found struct `Struct`
help: `Struct` implements `Trait` so you can box both arms and coerce to the trait object `Box<dyn Trait>`
|
LL ~ Box::new(bar()) as Box<dyn Trait>
LL | } else {
LL ~ Box::new(Struct)
|
```
Partially address #102629.
Split Diagnostics for Uncommon Codepoints: Add List to Display Characters Involved
This Pull Request adds a list of the uncommon codepoints involved in the `uncommon_codepoints` lint, as outlined as a first step in #120228.
Example rendered diagnostic:
```
error: identifier contains an uncommon Unicode codepoint: 'µ'
--> $DIR/lint-uncommon-codepoints.rs:3:7
|
LL | const µ: f64 = 0.000001;
| ^
|
note: the lint level is defined here
--> $DIR/lint-uncommon-codepoints.rs:1:9
|
LL | #![deny(uncommon_codepoints)]
| ^^^^^^^^^^^^^^^^^^^
```
(Retrying #120258.)
Add `#[coverage(off)]` to closures introduced by `#[test]` and `#[bench]`
These closures are an internal implementation detail of the `#[test]` and `#[bench]` attribute macros, so from a user perspective there is no reason to instrument them for coverage.
Skipping them makes coverage reports slightly cleaner, and will also allow other changes to span processing during coverage instrumentation, without having to worry about how they affect the `#[test]` macro.
The `#[coverage(off)]` attribute has no effect when `-Cinstrument-coverage` is not used.
Fixes#120046.
---
Note that this PR has no effect on the user-written function that has the `#[test]` attribute attached to it. That function will still be instrumented as normal.
Do not normalize closure signature when building `FnOnce` shim
It is not necessary to normalize the closure signature when building an `FnOnce` shim for an `Fn`/`FnMut` closure. That closure shim is just calling `FnMut::call_mut(&mut self)` anyways.
It's also somewhat sketchy that we were ever doing this to begin with, since we're normalizing with a `ParamEnv::reveal_all()` param-env, which is definitely not right with possibly polymorphic substs.
This cuts out a tiny bit of unnecessary work in `Instance::resolve` and simplifies the signature because now we can unconditionally return an `Instance`.
A bunch of random modifications
r? oli-obk
Kitchen sink of changes that I didn't know where to put elsewhere. Documentation tweaks mostly, but also removing some unreachable code and simplifying the pretty printing for closures/coroutines.
These were added with good intentions, but a recent change in LLVM 18
emits a warning while examining .rmeta sections in .rlib files. Since
this flag is a nice-to-have and users can update their LLVM linker
independently of rustc's LLVM version, we can just omit the flag.
const-eval interning: get rid of type-driven traversal
This entirely replaces our const-eval interner, i.e. the code that takes the final result of a constant evaluation from the local memory of the const-eval machine to the global `tcx` memory. The main goal of this change is to ensure that we can detect mutable references that sneak into this final value -- this is something we want to reject for `static` and `const`, and while const-checking performs some static analysis to ensure this, I would be much more comfortable stabilizing const_mut_refs if we had a dynamic check that sanitizes the final value. (This is generally the approach we have been using on const-eval: do a static check to give nice errors upfront, and then do a dynamic check to be really sure that the properties we need for soundness, actually hold.)
We can do this now that https://github.com/rust-lang/rust/pull/118324 landed and each pointer comes with a bit (completely independent of its type) storing whether mutation is permitted through this pointer or not.
The new interner is a lot simpler than the old one: previously we did a complete type-driven traversal to determine the mutability of all memory we see, and then a second pass to intern any leftover raw pointers. The new interner simply recursively traverses the allocation holding the final result, and all allocations reachable from it (which can be determined from the raw bytes of the result, without knowing anything about types), and ensures they all get interned. The initial allocation is interned as immutable for `const` and pomoted and non-interior-mutable `static`; all other allocations are interned as immutable for `static`, `const`, and promoted. The main subtlety is justifying that those inner allocations may indeed be interned immutably, i.e., that mutating them later would anyway already be UB:
- for promoteds, we rely on the analysis that does promotion to ensure that this is sound.
- for `const` and `static`, we check that all pointers in the final result that point to things that are new (i.e., part of this const evaluation) are immutable, i.e., were created via `&<expr>` at a non-interior-mutable type. Mutation through immutable pointers is UB so we are free to intern that memory as immutable.
Interning raises an error if it encounters a dangling pointer or a mutable pointer that violates the above rules.
I also extended our type-driven const validity checks to ensure that `&mut T` in the final value of a const points to mutable memory, at least if `T` is not zero-sized. This catches cases of people turning `&i32` into `&mut i32` (which would still be considered a read-only pointer). Similarly, when these checks encounter an `UnsafeCell`, they are checking that it lives in mutable memory. (Both of these only traverse the newly created values; if those point to other consts/promoteds, the check stops there. But that's okay, we don't have to catch all the UB.) I co-developed this with the stricter interner changes but I can split it out into a separate PR if you prefer.
This PR does have the immediate effect of allowing some new code on stable, for instance:
```rust
const CONST_RAW: *const Vec<i32> = &Vec::new() as *const _;
```
Previously that code got rejected since the type-based interner didn't know what to do with that pointer. It's a raw pointer, we cannot trust its type. The new interner does not care about types so it sees no issue with this code; there's an immutable pointer pointing to some read-only memory (storing a `Vec<i32>`), all is good. Accepting this code pretty much commits us to non-type-based interning, but I think that's the better strategy anyway.
This PR also leads to slightly worse error messages when the final value of a const contains a dangling reference. Previously we would complete interning and then the type-based validation would detect this dangling reference and show a nice error saying where in the value (i.e., in which field) the dangling reference is located. However, the new interner cannot distinguish dangling references from dangling raw pointers, so it must throw an error when it encounters either of them. It doesn't have an understanding of the value structure so all it can say is "somewhere in this constant there's a dangling pointer". (Later parts of the compiler don't like dangling pointers/references so we have to reject them either during interning or during validation.) This could potentially be improved by doing validation before interning, but that's a larger change that I have not attempted yet. (It's also subtle since we do want validation to use the final mutability bits of all involved allocations, and currently it is interning that marks a bunch of allocations as immutable -- that would have to still happen before validation.)
`@rust-lang/wg-const-eval` I hope you are okay with this plan. :)
`@rust-lang/lang` paging you in since this accepts new code on stable as explained above. Please let me know if you think FCP is necessary.
Only use dense bitsets in dataflow analyses
When a dataflow state has the size close to the number of locals, we should prefer a dense bitset, like we already store locals in a dense vector.
Other occurrences of `ChunkedBitSet` need to be justified by the size of the dataflow state.
riscv32im-risc0-zkvm-elf: add target
This pull request adds RISC Zero's Zero Knowledge Virtual Machine (zkVM) as a target for rust. The zkVM used to produce proofs of execution of RISC-V ELF binaries. In order to do this, the target will execute the ELF to generate a receipt containing the output of the computation along with a cryptographic seal. This receipt can be verified to ensure the integrity of the computation and its result. This target is implemented as software only; it has no hardware implementation.
## Tier 3 target policy:
Here is a copy of the tier 3 target policy:
> Tier 3 target policy:
>
> At this tier, the Rust project provides no official support for a target, so we
> place minimal requirements on the introduction of targets.
>
> A proposed new tier 3 target must be reviewed and approved by a member of the
> compiler team based on these requirements. The reviewer may choose to gauge
> broader compiler team consensus via a [[Major Change Proposal (MCP)](https://forge.rust-lang.org/compiler/mcp.html)](https://forge.rust-lang.org/compiler/mcp.html).
>
> A proposed target or target-specific patch that substantially changes code
> shared with other targets (not just target-specific code) must be reviewed and
> approved by the appropriate team for that shared code before acceptance.
>
> - A tier 3 target must have a designated developer or developers (the "target
> maintainers") on record to be CCed when issues arise regarding the target.
> (The mechanism to track and CC such developers may evolve over time.)
The maintainers are named in the target description file
> - Targets must use naming consistent with any existing targets; for instance, a
> target for the same CPU or OS as an existing Rust target should use the same
> name for that CPU or OS. Targets should normally use the same names and
> naming conventions as used elsewhere in the broader ecosystem beyond Rust
> (such as in other toolchains), unless they have a very good reason to
> diverge. Changing the name of a target can be highly disruptive, especially
> once the target reaches a higher tier, so getting the name right is important
> even for a tier 3 target.
> - Target names should not introduce undue confusion or ambiguity unless
> absolutely necessary to maintain ecosystem compatibility. For example, if
> the name of the target makes people extremely likely to form incorrect
> beliefs about what it targets, the name should be changed or augmented to
> disambiguate it.
> - If possible, use only letters, numbers, dashes and underscores for the name.
> Periods (`.`) are known to cause issues in Cargo.
>
We understand.
> - Tier 3 targets may have unusual requirements to build or use, but must not
> create legal issues or impose onerous legal terms for the Rust project or for
> Rust developers or users.
> - The target must not introduce license incompatibilities.
We understand and will not introduce incompatibilities. All of our code that we publish is licensed under Apache-2.0.
> - Anything added to the Rust repository must be under the standard Rust license (`MIT OR Apache-2.0`).
We understand. We are open to either license for the Rust repository.
> - The target must not cause the Rust tools or libraries built for any other
> host (even when supporting cross-compilation to the target) to depend
> on any new dependency less permissive than the Rust licensing policy. This
> applies whether the dependency is a Rust crate that would require adding
> new license exceptions (as specified by the `tidy` tool in the
> rust-lang/rust repository), or whether the dependency is a native library
> or binary. In other words, the introduction of the target must not cause a
> user installing or running a version of Rust or the Rust tools to be
> subject to any new license requirements.
We understand. The runtime libraries and the execution environment and software associated with this environment uses `Apache-2.0` so this should not be an issue.
> - Compiling, linking, and emitting functional binaries, libraries, or other
> code for the target (whether hosted on the target itself or cross-compiling
> from another target) must not depend on proprietary (non-FOSS) libraries.
> Host tools built for the target itself may depend on the ordinary runtime
> libraries supplied by the platform and commonly used by other applications
> built for the target, but those libraries must not be required for code
> generation for the target; cross-compilation to the target must not require
> such libraries at all. For instance, `rustc` built for the target may
> depend on a common proprietary C runtime library or console output library,
> but must not depend on a proprietary code generation library or code
> optimization library. Rust's license permits such combinations, but the
> Rust project has no interest in maintaining such combinations within the
> scope of Rust itself, even at tier 3.
We understand. We only depend on FOSS libraries. Dependencies such as runtime libraries for this target are licensed as `Apache-2.0`.
> - "onerous" here is an intentionally subjective term. At a minimum, "onerous"
> legal/licensing terms include but are *not* limited to: non-disclosure
> requirements, non-compete requirements, contributor license agreements
> (CLAs) or equivalent, "non-commercial"/"research-only"/etc terms,
> requirements conditional on the employer or employment of any particular
> Rust developers, revocable terms, any requirements that create liability
> for the Rust project or its developers or users, or any requirements that
> adversely affect the livelihood or prospects of the Rust project or its
> developers or users.
There are no such terms present
> - Neither this policy nor any decisions made regarding targets shall create any
> binding agreement or estoppel by any party. If any member of an approving
> Rust team serves as one of the maintainers of a target, or has any legal or
> employment requirement (explicit or implicit) that might affect their
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Revert stabilization of trait_upcasting feature
Reverts #118133
This reverts commit 6d2b84b3ed, reversing changes made to 73bc12199e.
The feature has a soundness bug:
* #120222
It is unclear to me whether we'll actually want to destabilize, but I thought it was still prudent to open the PR for easy destabilization once we get there.
Fix a `trimmed_def_paths` assertion failure.
`RegionHighlightMode::force_print_trimmed_def_path` can call `trimmed_def_paths` even when `tcx.sess.opts.trimmed_def_paths` is false. Based on the `force` in the method name, it seems this is deliberate, so I have removed the assertion.
Fixes#120035.
r? `@compiler-errors`
Track `verbose` and `verbose_internals`
`verbose_internals` has been UNTRACKED since it was introduced. When i added `verbose` in https://github.com/rust-lang/rust/pull/119129 i made it UNTRACKED as well.
``@bjorn3`` says: https://github.com/rust-lang/rust/pull/119286#discussion_r1436134354
> On errors we don't finalize the incr comp cache, but non-fatal diagnostics are cached afaik.
Otherwise we would have to replay the query in question, which we may not be able to do if the query key is not reconstructible from the dep node fingerprint.
So we must track these flags to avoid replaying incorrect diagnostics.
r? incremental
Consolidate logic around resolving built-in coroutine trait impls
Deduplicates a lot of code. Requires defining a new lang item for `Coroutine::resume` for consistency, but it seems not harmful at worst, and potentially later useful at best.
r? oli-obk
never_patterns: Count `!` bindings as diverging
A binding that is a never pattern is not reachable, hence counts as diverging code. This allows in particular `fn foo(!: Void) -> SomeType {}` to typecheck.
r? ``@compiler-errors``
When encountering
```rust
let _ = if true {
Struct
} else {
foo() // -> Box<dyn Trait>
};
```
if `Struct` implements `Trait`, suggest boxing the then arm tail expression.
Part of #102629.
