Fix span note for question mark expression
Fixesrust-lang/rust#144304
Seems it's better to fix the note instead of modifying the span to cover the whole expression.
r? `@estebank`
Extend well-formedness checking and HIR analysis to prohibit the use of
scalable vectors in structs, enums, unions, tuples and arrays. LLVM does
not support scalable vectors being members of other types, so these
restrictions are necessary.
Co-authored-by: Jamie Cunliffe <Jamie.Cunliffe@arm.com>
Move `struct Placeholder<T>`
r? ghost
Couple of issues I've encountered;
- `compiler/rustc_infer/src/infer/region_constraints/mod.rs` `GenericKind` I can't call `write!(f, "{p}")` due to error 1. Which looks like I may need to implement `Lift` for `Placeholder`?
- Using the `define_print_and_forward_display!` for `ty::PlaceholderType` caused error 2, as I've moved the struct it no longer exists in the crate. I suspect because I'm not using that macro it causes the error for `GenericKind`
<details>
<summary>Error 1</summary>
```
error: lifetime may not live long enough
--> compiler/rustc_infer/src/infer/region_constraints/mod.rs:672:38
|
668 | impl<'tcx> fmt::Display for GenericKind<'tcx> {
| ---- lifetime `'tcx` defined here
...
672 | GenericKind::Placeholder(ref p) => write!(f, "{p}"),
| ^^^^^ assignment requires that `'tcx` must outlive `'static`
|
= note: requirement occurs because of the type `rustc_middle::ty::TyCtxt<'_>`, which makes the generic argument `'_` invariant
= note: the struct `rustc_middle::ty::TyCtxt<'tcx>` is invariant over the parameter `'tcx`
= help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
error: implementation of `Lift` is not general enough
--> compiler/rustc_infer/src/infer/region_constraints/mod.rs:672:38
|
672 | GenericKind::Placeholder(ref p) => write!(f, "{p}"),
| ^^^^^ implementation of `Lift` is not general enough
|
= note: `Lift<rustc_middle::ty::TyCtxt<'0>>` would have to be implemented for the type `rustc_type_ir::Placeholder<rustc_middle::ty::TyCtxt<'_>, BoundTy>`, for any lifetime `'0`...
= note: ...but `Lift<rustc_middle::ty::TyCtxt<'1>>` is actually implemented for the type `rustc_type_ir::Placeholder<rustc_middle::ty::TyCtxt<'1>, BoundTy>`, for some specific lifetime `'1`
error: implementation of `Print` is not general enough
--> compiler/rustc_infer/src/infer/region_constraints/mod.rs:672:38
|
672 | GenericKind::Placeholder(ref p) => write!(f, "{p}"),
| ^^^^^ implementation of `Print` is not general enough
```
</details>
<details>
<summary>Error 2</summary>
```
error[E0117]: only traits defined in the current crate can be implemented for arbitrary types
--> compiler/rustc_middle/src/ty/print/pretty.rs:3060:38
|
3057 | / macro_rules! forward_display_to_print {
3058 | | ($($ty:ty),+) => {
3059 | | // Some of the $ty arguments may not actually use 'tcx
3060 | | $(#[allow(unused_lifetimes)] impl<'tcx> fmt::Display for $ty {
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
... |
3072 | | };
3073 | | }
| |_- in this expansion of `forward_display_to_print!`
...
3093 | / forward_display_to_print! {
3094 | | ty::Region<'tcx>,
3095 | | Ty<'tcx>,
3096 | | &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
3097 | | ty::Const<'tcx>,
3098 | | &'tcx ty::PlaceholderType<'tcx>
| | ------------------------------- `rustc_type_ir::Placeholder` is not defined in the current crate
3099 | | }
| |_- in this macro invocation
|
= note: impl doesn't have any local type before any uncovered type parameters
= note: for more information see https://doc.rust-lang.org/reference/items/implementations.html#orphan-rules
= note: define and implement a trait or new type instead
error: implementation of `Lift` is not general enough
--> compiler/rustc_middle/src/ty/print/pretty.rs:3060:38
|
3057 | / macro_rules! forward_display_to_print {
3058 | | ($($ty:ty),+) => {
3059 | | // Some of the $ty arguments may not actually use 'tcx
3060 | | $(#[allow(unused_lifetimes)] impl<'tcx> fmt::Display for $ty {
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Lift` is not general enough
... |
3072 | | };
3073 | | }
| |_- in this expansion of `forward_display_to_print!`
...
3093 | / forward_display_to_print! {
3094 | | ty::Region<'tcx>,
3095 | | Ty<'tcx>,
3096 | | &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
3097 | | ty::Const<'tcx>,
3098 | | &'tcx ty::PlaceholderType<'tcx>
3099 | | }
| |_- in this macro invocation
|
= note: `Lift<context::TyCtxt<'0>>` would have to be implemented for the type `rustc_type_ir::Placeholder<context::TyCtxt<'tcx>, BoundTy>`, for any lifetime `'0`...
= note: ...but `Lift<context::TyCtxt<'1>>` is actually implemented for the type `rustc_type_ir::Placeholder<context::TyCtxt<'1>, BoundTy>`, for some specific lifetime `'1`
error: implementation of `print::Print` is not general enough
--> compiler/rustc_middle/src/ty/print/pretty.rs:3060:38
|
3057 | / macro_rules! forward_display_to_print {
3058 | | ($($ty:ty),+) => {
3059 | | // Some of the $ty arguments may not actually use 'tcx
3060 | | $(#[allow(unused_lifetimes)] impl<'tcx> fmt::Display for $ty {
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `print::Print` is not general enough
... |
3072 | | };
3073 | | }
| |_- in this expansion of `forward_display_to_print!`
...
3093 | / forward_display_to_print! {
3094 | | ty::Region<'tcx>,
3095 | | Ty<'tcx>,
3096 | | &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
3097 | | ty::Const<'tcx>,
3098 | | &'tcx ty::PlaceholderType<'tcx>
3099 | | }
| |_- in this macro invocation
|
= note: `print::Print<'0, print::pretty::FmtPrinter<'a, '0>>` would have to be implemented for the type `rustc_type_ir::Placeholder<context::TyCtxt<'tcx>, BoundTy>`, for any lifetime `'0`...
= note: ...but `print::Print<'1, print::pretty::FmtPrinter<'a, 'tcx>>` is actually implemented for the type `rustc_type_ir::Placeholder<context::TyCtxt<'1>, BoundTy>`, for some specific lifetime `'1`
error: specializing impl repeats parameter `'tcx`
--> compiler/rustc_middle/src/ty/print/pretty.rs:3060:38
|
3057 | / macro_rules! forward_display_to_print {
3058 | | ($($ty:ty),+) => {
3059 | | // Some of the $ty arguments may not actually use 'tcx
3060 | | $(#[allow(unused_lifetimes)] impl<'tcx> fmt::Display for $ty {
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
... |
3072 | | };
3073 | | }
| |_- in this expansion of `forward_display_to_print!`
...
3093 | / forward_display_to_print! {
3094 | | ty::Region<'tcx>,
3095 | | Ty<'tcx>,
3096 | | &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
3097 | | ty::Const<'tcx>,
3098 | | &'tcx ty::PlaceholderType<'tcx>
3099 | | }
| |_- in this macro invocation
error[E0277]: the trait bound `&Placeholder<TyCtxt<'tcx>, BoundTy>: Lift<...>` is not satisfied
--> compiler/rustc_middle/src/ty/print/pretty.rs:3064:30
|
3057 | / macro_rules! forward_display_to_print {
3058 | | ($($ty:ty),+) => {
3059 | | // Some of the $ty arguments may not actually use 'tcx
3060 | | $(#[allow(unused_lifetimes)] impl<'tcx> fmt::Display for $ty {
... |
3064 | | tcx.lift(*self)
| | ---- ^^^^^ unsatisfied trait bound
| | |
| | required by a bound introduced by this call
... |
3072 | | };
3073 | | }
| |_- in this expansion of `forward_display_to_print!`
...
3093 | / forward_display_to_print! {
3094 | | ty::Region<'tcx>,
3095 | | Ty<'tcx>,
3096 | | &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
3097 | | ty::Const<'tcx>,
3098 | | &'tcx ty::PlaceholderType<'tcx>
3099 | | }
| |_- in this macro invocation
|
= help: the trait `Lift<context::TyCtxt<'_>>` is not implemented for `&rustc_type_ir::Placeholder<context::TyCtxt<'tcx>, BoundTy>`
note: required by a bound in `context::TyCtxt::<'tcx>::lift`
--> compiler/rustc_middle/src/ty/context.rs:1807:20
|
1807 | pub fn lift<T: Lift<TyCtxt<'tcx>>>(self, value: T) -> Option<T::Lifted> {
| ^^^^^^^^^^^^^^^^^^ required by this bound in `TyCtxt::<'tcx>::lift`
= note: the full name for the type has been written to '/home/jambar02/Documents/arm/rust/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc_middle-16e5c44041028d8b.long-type-3843651570422266958.txt'
= note: consider using `--verbose` to print the full type name to the console
help: consider dereferencing here
|
3064 | tcx.lift(**self)
| +
error[E0282]: type annotations needed
--> compiler/rustc_middle/src/ty/print/pretty.rs:3064:21
|
3057 | / macro_rules! forward_display_to_print {
3058 | | ($($ty:ty),+) => {
3059 | | // Some of the $ty arguments may not actually use 'tcx
3060 | | $(#[allow(unused_lifetimes)] impl<'tcx> fmt::Display for $ty {
... |
3064 | |/ tcx.lift(*self)
3065 | || .expect("could not lift for printing")
| ||______________________________________________________________^ cannot infer type
... |
3072 | | };
3073 | | }
| |__- in this expansion of `forward_display_to_print!`
...
3093 | / forward_display_to_print! {
3094 | | ty::Region<'tcx>,
3095 | | Ty<'tcx>,
3096 | | &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
3097 | | ty::Const<'tcx>,
3098 | | &'tcx ty::PlaceholderType<'tcx>
3099 | | }
| |_- in this macro invocation
```
</details>
```
error[E0277]: the size for values of type `(dyn Debug + 'static)` cannot be known at compilation time
--> $DIR/dyn-trait-type-alias-return-type.rs:4:11
|
LL | fn f() -> T { loop {} }
| ^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `(dyn Debug + 'static)`
note: this type alias is unsized
--> $DIR/dyn-trait-type-alias-return-type.rs:1:1
|
LL | type T = dyn core::fmt::Debug;
| ^^^^^^
= note: the return type of a function must have a statically known size
```
Use `TypingMode::PostAnalysis` in `try_evaluate_const`
As mentioned in https://github.com/rust-lang/rust/pull/148698#discussion_r2541882341, we should use ``TypingMode::PostAnalysis`` for that path.
````@BoxyUwU```` prefer the match in ``try_evaluate_const`` to be exhaustive, so I also included that in this PR :3
Add a diagnostic attribute for special casing const bound errors for non-const impls
Somewhat of a follow-up to https://github.com/rust-lang/rust/pull/144194
My plan is to resolve
f4e19c6878/compiler/rustc_hir_typeck/src/callee.rs (L907-913)
but doing so without being able to mark impls the way I do in this PR wrould cause all nice diagnostics about for loops and pointer comparisons to just be a `*const u32 does not implement [const] PartialEq` errors.
Currently, If `expected_def_id` and `another_trait_def_id` have their
crate imported as ExternCrateSource::Path the method
get_extern_crate_renamed_symbol() will return None for both, resulting
in a false positive. This fixes the issue by using a slitly different
approach, we use a predicate instead and do the comparison of the item
names only when both crates are imported as ExternCrateSource::Extern and
are direct dependencies of the LOCAL_CRATE, otherwise false is returned.
This is useful when you have two dependencies that use different trait for
the same thing and with the same name. The user can accidentally implement
the bad one which might be confusing. This commits refactorizes existing
diagnostics about multiple different crates with the same version and adds
a note when similarly named traits are found. All diagnostics are merged
into a single one.
Special case detecting `'static` lifetime requirement coming from `-> Box<dyn Trait>`
```
error[E0310]: the parameter type `R` may not live long enough
--> $DIR/implicit-static-lifetime-in-dyn-trait-return-type.rs:10:5
|
LL | fn bb<R>(r: R) -> Box<dyn Foo> {
| ------- this `dyn Trait` has an implicit `'static` lifetime bound
LL | Box::new(Bar(r))
| ^^^^^^^^^^^^^^^^
| |
| the parameter type `R` must be valid for the static lifetime...
| ...so that the type `R` will meet its required lifetime bounds
|
help: consider adding an explicit lifetime bound
|
LL | fn bb<R: 'static>(r: R) -> Box<dyn Foo> {
| +++++++++
```
Partly address rust-lang/rust#41966 and rust-lang/rust#54753. rust-lang/rust#103849, which shows a case where there's an intermediary binding, is not addressed at all, as aren't cases *other* than `Box<dyn Trait>` return type.
stop specializing on `Copy`
fixes https://github.com/rust-lang/rust/issues/132442
`std` specializes on `Copy` to optimize certain library functions such as `clone_from_slice`. This is unsound, however, as the `Copy` implementation may not be always applicable because of lifetime bounds, which specialization does not take into account; the result being that values are copied even though they are not `Copy`. For instance, this code:
```rust
struct SometimesCopy<'a>(&'a Cell<bool>);
impl<'a> Clone for SometimesCopy<'a> {
fn clone(&self) -> Self {
self.0.set(true);
Self(self.0)
}
}
impl Copy for SometimesCopy<'static> {}
let clone_called = Cell::new(false);
// As SometimesCopy<'clone_called> is not 'static, this must run `clone`,
// setting the value to `true`.
let _ = [SometimesCopy(&clone_called)].clone();
assert!(clone_called.get());
```
should not panic, but does ([playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=6be7a48cad849d8bd064491616fdb43c)).
To solve this, this PR introduces a new `unsafe` trait: `TrivialClone`. This trait may be implemented whenever the `Clone` implementation is equivalent to copying the value (so e.g. `fn clone(&self) -> Self { *self }`). Because of lifetime erasure, there is no way for the `Clone` implementation to observe lifetime bounds, meaning that even if the `TrivialClone` has stricter bounds than the `Clone` implementation, its invariant still holds. Therefore, it is sound to specialize on `TrivialClone`.
I've changed all `Copy` specializations in the standard library to specialize on `TrivialClone` instead. Unfortunately, the unsound `#[rustc_unsafe_specialization_marker]` attribute on `Copy` cannot be removed in this PR as `hashbrown` still depends on it. I'll make a PR updating `hashbrown` once this lands.
With `Copy` no longer being considered for specialization, this change alone would result in the standard library optimizations not being applied for user types unaware of `TrivialClone`. To avoid this and restore the optimizations in most cases, I have changed the expansion of `#[derive(Clone)]`: Currently, whenever both `Clone` and `Copy` are derived, the `clone` method performs a copy of the value. With this PR, the derive macro also adds a `TrivialClone` implementation to make this case observable using specialization. I anticipate that most users will use `#[derive(Clone, Copy)]` whenever both are applicable, so most users will still profit from the library optimizations.
Unfortunately, Hyrum's law applies to this PR: there are some popular crates which rely on the precise specialization behaviour of `core` to implement "specialization at home", e.g. [`libAFL`](89cff63702/libafl_bolts/src/tuples.rs (L27-L49)). I have no remorse for breaking such horrible code, but perhaps we should open other, better ways to satisfy their needs – for example by dropping the `'static` bound on `TypeId::of`...
mgca: Add ConstArg representation for const items
tracking issue: rust-lang/rust#132980fixesrust-lang/rust#131046fixesrust-lang/rust#134641
As part of implementing `min_generic_const_args`, we need to distinguish const items that can be used in the type system, such as in associated const equality projections, from const items containing arbitrary const code, which must be kept out of the type system. Specifically, all "type consts" must be either concrete (no generics) or generic with a trivial expression like `N` or a path to another type const item.
To syntactically distinguish these cases, we require, for now at least, that users annotate all type consts with the `#[type_const]` attribute. Then, we validate that the const's right-hand side is indeed eligible to be a type const and represent it differently in the HIR.
We accomplish this representation using a new `ConstItemRhs` enum in the HIR, and a similar but simpler enum in the AST. When `#[type_const]` is **not** applied to a const (e.g. on stable), we represent const item right-hand sides (rhs's) as HIR bodies, like before. However, when the attribute is applied, we instead lower to a `hir::ConstArg`. This syntactically distinguishes between trivial const args (paths) and arbitrary expressions, which are represented using `AnonConst`s. Then in `generics_of`, we can take advantage of the existing machinery to bar the `AnonConst` rhs's from using parent generics.
Early return if span is from expansion so we dont get empty span and ice later on
Fixes https://github.com/rust-lang/rust/issues/147255
The problem original was from that stmt.span was from expansion and it span was bigger than right part which is block.span, so it causes empty span and panic later on, I decided to add checks for both of them to be on the safe side
r? `@fmease` (you were in discussion on this issue so I decided to assign you, feel free to reroll)
Fix ICE from lit_to_mir_constant caused by type error
Fixesrust-lang/rust#148515
we still need to mark that there were errors to prevent later phases (like MIR building) from proceeding.
```
error[E0310]: the parameter type `R` may not live long enough
--> $DIR/implicit-static-lifetime-in-dyn-trait-return-type.rs:10:5
|
LL | fn bb<R>(r: R) -> Box<dyn Foo> {
| ------- this `dyn Trait` has an implicit `'static` lifetime bound
LL | Box::new(Bar(r))
| ^^^^^^^^^^^^^^^^
| |
| the parameter type `R` must be valid for the static lifetime...
| ...so that the type `R` will meet its required lifetime bounds
|
help: consider adding an explicit lifetime bound
|
LL | fn bb<R: 'static>(r: R) -> Box<dyn Foo> {
| +++++++++
```
Rollup of 5 pull requests
Successful merges:
- rust-lang/rust#144194 (Provide additional context to errors involving const traits)
- rust-lang/rust#148232 (ci: add runners for vanilla LLVM 21)
- rust-lang/rust#148240 (rustc_codegen: fix musttail returns for cast/indirect ABIs)
- rust-lang/rust#148247 (Remove a special case and move another one out of reachable_non_generics)
- rust-lang/rust#148370 (Point at inner item when it uses generic type param from outer item or `Self`)
r? `@ghost`
`@rustbot` modify labels: rollup
When encountering an unmet `Ty: [const] Trait` bound, if `Trait` is `#[const_trait]` and there's an `impl Trait for Ty` point at it. If local, suggest `impl const Trait for Ty`, otherwise just point at it.
```
error[E0277]: the trait bound `NonConstAdd: [const] Add` is not satisfied
--> $DIR/assoc-type.rs:37:16
|
LL | type Bar = NonConstAdd;
| ^^^^^^^^^^^
|
note: required by a bound in `Foo::Bar`
--> $DIR/assoc-type.rs:33:15
|
LL | type Bar: [const] Add;
| ^^^^^^^^^^^ required by this bound in `Foo::Bar`
help: make the `impl` of trait `Add` `const`
|
LL | impl const Add for NonConstAdd {
| +++++
```
```
error[E0277]: the trait bound `T: [const] PartialEq` is not satisfied
--> tests/ui/traits/const-traits/call-generic-method-fail.rs:5:5
|
5 | *t == *t
| ^^^^^^^^
|
note: trait `PartialEq` is implemented but not `const`
--> /home/gh-estebank/rust/library/core/src/ptr/const_ptr.rs:1590:1
|
1590 | impl<T: PointeeSized> PartialEq for *const T {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: trait `PartialEq` is implemented but not `const`
--> /home/gh-estebank/rust/library/core/src/ptr/mut_ptr.rs:2011:1
|
2011 | impl<T: PointeeSized> PartialEq for *mut T {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
