Rollup of 7 pull requests
Successful merges:
- #100508 (avoid making substs of type aliases late bound when used as fn args)
- #101381 (Test that target feature mix up with homogeneous floats is sound)
- #103353 (Fix Access Violation when using lld & ThinLTO on windows-msvc)
- #103521 (Avoid possible infinite loop when next_point reaching the end of file)
- #103559 (first move on a nested span_label)
- #103778 (Update several crates for improved support of the new targets)
- #103827 (Properly remap and check for substs compatibility in `confirm_impl_trait_in_trait_candidate`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
avoid making substs of type aliases late bound when used as fn args
fixes#47511fixes#85533
(although I did not know theses issues existed when i was working on this 🙃)
currently `Alias<...>` is treated the same as `Struct<...>` when deciding if generics should be late bound or early bound but this is not correct as `Alias` might normalize to a projection which does not constrain the generics.
I think this needs more tests before merging
more explanation of PR [here](https://hackmd.io/v44a-QVjTIqqhK9uretyQg?view)
Hackmd inline for future readers:
---
This assumes reader is familiar with the concept of early/late bound lifetimes. There's a section on rustc-dev-guide if not (although i think some details are a bit out of date)
## problem & background
Not all lifetimes on a fn can be late bound:
```rust
fn foo<'a>() -> &'a ();
impl<'a> Fn<()> for FooFnDef {
type Output = &'a (); // uh oh unconstrained lifetime
}
```
so we make make them early bound
```rust
fn foo<'a>() -> &'a ();
impl<'a> Fn<()> for FooFnDef<'a> {// wow look at all that lifetimey
type Output = &'a ();
}
```
(Closures have the same constraint however it is not enforced leading to soundness bugs, [#84385](https://github.com/rust-lang/rust/pull/84385) implements this "downgrading late bound to early bound" for closures)
lifetimes on fn items are only late bound when they are "constrained" by the fn args:
```rust
fn foo<'a>(_: &'a ()) -> &'a ();
// late bound, not present on `FooFnItem`
// vv
impl<'a> Trait<(&'a (),)> for FooFnItem {
type Output = &'a ();
}
// projections do not constrain inputs
fn bar<'a, T: Trait>(_: <T as Trait<'a>>::Assoc) -> &'a (); // early bound
// vv
impl<'a, T: Trait> Fn<(<T as Trait<'a>>::Assoc,)> for BarFnItem<'a, T> {
type Output = &'a ();
}
```
current logic for determining if inputs "constrain" a lifetime works off of HIR so does not normalize aliases. It also assumes that any path with no self type constrains all its substs (i.e. `Foo<'a, u32>` has no self type but `T::Assoc` does). This falls apart for top level type aliases (see linked issues):
```rust
type Alias<'a, T> = <T as Trait<'a>>::Assoc;
// wow look its a path with no self type uwu
// i bet that constrains `'a` so it should be latebound
// vvvvvvvvvvv
fn foo<'a, T: Trait>(_: Alias<'a, T>) -> &'a ();
// `Alias` normalized to make things clearer
// vvvvvvvvvvvvvvvvvvvvvvv
impl<'a, T: Trait> Fn<(<T as Trait<'a>>::Assoc,)> for FooFnDef<T> {
type Output = &'a ();
// oh no `'a` isnt constrained wah wah waaaah *trumbone noises*
// i think, idk what musical instrument that is
}
```
## solution
The PR solves this by having the hir visitor that checks for lifetimes in constraining uses check if the path is a `DefKind::Alias`. If it is we ""normalize"" it by calling `type_of` and walking the returned type. This is a bit hacky as it requires a mapping between the substs on the path in hir, and the generics of the `type Alias<...>` which is on the ty layer.
Alternative solutions may involve calculating the "late boundness" of lifetimes after/during astconv rather than relying on hir at all. We already have code to determine whether a lifetime SHOULD be late bound or not as this is currently how the error for `fn foo<'a, T: Trait>(_: Alias<'a, T>) -> &'a ();` gets emitted.
It is probably not possible to do this right now, late boundness is used by `generics_of` and `gather_explicit_predicates_of` as we currently do not put late bound lifetimes in `Generics`. Although this seems sus to me as the long term goal is to make all generics late bound which would result in `generics_of(function)` being empty? [#103448](https://github.com/rust-lang/rust/pull/103448) places all lifetimes in `Generics` regardless of late boundness so that may be a good step towards making this possible.
Better error for HRTB error from generator interior
cc #100013
This is just a first pass at an error. It could be better, and shouldn't really be emitted in the first place. But this is better than what was being emitted before.
Make InferCtxtExt use a FxIndexMap
This should be faster, because the map is only being used to iterate,
which is supposed to be faster with the IndexMap
Make the user_computed_preds use an IndexMap
It is being used mostly for iteration, so the change shouldn't result in
a perf hit
Make the RegionDeps fields use an IndexMap
This change could be a perf hit. Both `larger` and `smaller` are used
for iteration, but they are also used for insertions.
Make types_without_default_bounds use an IndexMap
It uses extend, but it also iterates and removes items. Not sure if
this will be a perf hit.
Make InferTtxt.reported_trait_errors use an IndexMap
This change brought a lot of other changes. The map seems to have been
mostly used for iteration, so the performance shouldn't suffer.
Add FIXME to change ProvisionalEvaluationCache.map to use an IndexMap
Right now this results in a perf hit. IndexMap doesn't have
the `drain_filter` API, so in `on_completion` we now need to iterate two
times over the map.
Implement `std::marker::Tuple`, use it in `extern "rust-call"` and `Fn`-family traits
Implements rust-lang/compiler-team#537
I made a few opinionated decisions in this implementation, specifically:
1. Enforcing `extern "rust-call"` on fn items during wfcheck,
2. Enforcing this for all functions (not just ones that have bodies),
3. Gating this `Tuple` marker trait behind its own feature, instead of grouping it into (e.g.) `unboxed_closures`.
Still needing to be done:
1. Enforce that `extern "rust-call"` `fn`-ptrs are well-formed only if they have 1/2 args and the second one implements `Tuple`. (Doing this would fix ICE in #66696.)
2. Deny all explicit/user `impl`s of the `Tuple` trait, kinda like `Sized`.
3. Fixing `Tuple` trait built-in impl for chalk, so that chalkification tests are un-broken.
Open questions:
1. Does this need t-lang or t-libs signoff?
Fixes#99820
Fix late-bound lifetime closure ICEs in HIR typeck and MIR borrowck
During HIR typeck, we need to teach astconv to treat late-bound regions within a closure body as free, fixing escaping bound vars ICEs in both of the issues below.
However, this then gets us to MIR borrowck, which itself needs to be taught how to instantiate free region vids for late-bound regions that come from items that _aren't_ the typeck root (for now, just closures).
Fixes#103771Fixes#103736
fix(generic_const_exprs): Fix predicate inheritance for children of opaque types
Fixes#99705
We currently have a special case to perform predicate inheritance when the const item is in the generics. I think we're also going to need this for opaque return types. When evaluating the predicates applied to the associated item, it'll inherit from its parent, the opaque type, which will never have predicates applied. This PR bypass the opaque typed parent and inherit predicates directly from the function itself.
Change #[suggestion_*] attributes to use style="..."
As discussed [on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/336883-i18n/topic/.23100717.20tool_only_span_suggestion), this changes `#[(multipart_)suggestion_{short,verbose,hidden}(...)]` attributes to plain `#[(multipart_)suggestion(...)]` attributes with a `style = "{short,verbose,hidden}"` parameter.
It also adds a new style, `tool-only`, that corresponds to `tool_only_span_suggestion`/`tool_only_multipart_suggestion` and causes the suggestion to not be shown in human-readable output at all.
Best reviewed commit-by-commit, there's a bit of noise in there.
cc #100717 `@compiler-errors`
r? `@davidtwco`
Track where diagnostics were created.
This implements the `-Ztrack-diagnostics` flag, which uses `#[track_caller]` to track where diagnostics are created. It is meant as a debugging tool much like `-Ztreat-err-as-bug`.
For example, the following code...
```rust
struct A;
struct B;
fn main(){
let _: A = B;
}
```
...now emits the following error message:
```
error[E0308]: mismatched types
--> src\main.rs:5:16
|
5 | let _: A = B;
| - ^ expected struct `A`, found struct `B`
| |
| expected due to this
-Ztrack-diagnostics: created at compiler\rustc_infer\src\infer\error_reporting\mod.rs:2275:31
```
(almost) Always use `ObligationCtxt` when dealing with canonical queries
Hope this is a step in the right direction. cc rust-lang/types-team#50.
r? `@lcnr`
Enable varargs support for calling conventions other than C or cdecl
This patch makes it possible to use varargs for calling conventions,
which are either based on C (efiapi) or C is based on them (sysv64 and win64).
Also pinging ``@phlopsi,`` because he noticed first this oversight when writing a library for UEFI.
Accept `TyCtxt` instead of `TyCtxtAt` in `Ty::is_*` functions
Functions in answer:
- `Ty::is_freeze`
- `Ty::is_sized`
- `Ty::is_unpin`
- `Ty::is_copy_modulo_regions`
This allows to remove a lot of useless `.at(DUMMY_SP)`, making the code a bit nicer :3
r? `@compiler-errors`
Rename some `OwnerId` fields.
`@spastorino` noticed some silly expressions like `item_id.def_id.def_id`.
This commit renames several `def_id: OwnerId` fields as `owner_id`, so those expressions become `item_id.owner_id.def_id`.
`item_id.owner_id.local_def_id` would be even clearer, but the use of `def_id` for values of type `LocalDefId` is *very* widespread, so I left that alone.
r? `@compiler-errors`
spastorino noticed some silly expressions like `item_id.def_id.def_id`.
This commit renames several `def_id: OwnerId` fields as `owner_id`, so
those expressions become `item_id.owner_id.def_id`.
`item_id.owner_id.local_def_id` would be even clearer, but the use of
`def_id` for values of type `LocalDefId` is *very* widespread, so I left
that alone.
Note scope of TAIT more accurately
This maybe explains why the person was confused in #101897, since we say "same module" but really should've said "same impl".
r? ``@oli-obk``
Introduce UnordMap, UnordSet, and UnordBag (MCP 533)
This is the start of implementing [MCP 533](https://github.com/rust-lang/compiler-team/issues/533).
I followed `@eddyb's` suggestion of naming the collection types `Unord(Map/Set/Bag)` which is a bit easier to type than `Unordered(Map/Set/Bag)`
r? `@eddyb`
Emit a nicer error on `impl Self {`
currently it emits a "cycle detected error" but this PR makes it emit a more user friendly error specifically saying that `Self` is disallowed in that position. this is a pretty hacky fix so i dont expect this to be merged (I basically only made this PR because i wanted to see if CI passes)
r? ``@compiler-errors``
Remap early bound lifetimes in return-position `impl Trait` in traits too
Fixes part of #103457
r? ``@cjgillot,`` though feel free to reassign, just thought you'd have sufficient context to review.
Add suggestions for unsafe impl error codes
Adds suggestions for users to add `unsafe` to trait impls that should be `unsafe`, and remove `unsafe` from trait impls that do not require `unsafe`
With the folllowing code:
```rust
struct Foo {}
struct Bar {}
trait Safe {}
unsafe trait Unsafe {}
impl Safe for Foo {} // ok
impl Unsafe for Foo {} // E0200
unsafe impl Safe for Bar {} // E0199
unsafe impl Unsafe for Bar {} // ok
// omitted empty main fn
```
The current rustc output is:
```
error[E0199]: implementing the trait `Safe` is not unsafe
--> e0200.rs:13:1
|
13 | unsafe impl Safe for Bar {} // E0199
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0200]: the trait `Unsafe` requires an `unsafe impl` declaration
--> e0200.rs:11:1
|
11 | impl Unsafe for Foo {} // E0200
| ^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0199, E0200.
For more information about an error, try `rustc --explain E0199`.
```
With this PR, the future rustc output would be:
```
error[E0199]: implementing the trait `Safe` is not unsafe
--> ../../temp/e0200.rs:13:1
|
13 | unsafe impl Safe for Bar {} // E0199
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: remove `unsafe` from this trait implementation
|
13 - unsafe impl Safe for Bar {} // E0199
13 + impl Safe for Bar {} // E0199
|
error[E0200]: the trait `Unsafe` requires an `unsafe impl` declaration
--> ../../temp/e0200.rs:11:1
|
11 | impl Unsafe for Foo {} // E0200
| ^^^^^^^^^^^^^^^^^^^^^^
|
= note: the trait `Unsafe` enforces invariants that the compiler can't check. Review the trait documentation and make sure this implementation upholds those invariants before adding the `unsafe` keyword
help: add `unsafe` to this trait implementation
|
11 | unsafe impl Unsafe for Foo {} // E0200
| ++++++
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0199, E0200.
For more information about an error, try `rustc --explain E0199`.
```
``@rustbot`` label +T-compiler +A-diagnostics +A-suggestion-diagnostics
This patch makes it possible to use varargs for calling conventions,
which are either based on C (like efiapi) or C is based
on them (for example sysv64 and win64).
Flatten diagnostic slug modules
This makes it easier to grep for the slugs in the code.
See https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Localization.20infra.20interferes.20with.20grepping.20for.20error for more discussion about it.
This was mostly done with a few regexes and a bunch of manual work. This also exposes a pretty annoying inconsistency for the extra labels. Some of the extra labels are defined as additional properties in the fluent message (which makes them not prefixed with the crate name) and some of them are new fluent messages themselves (which makes them prefixed with the crate name). I don't know whether we want to clean this up at some point but it's useful to know.
r? `@davidtwco`
Introduce `subst_iter` and `subst_iter_copied` on `EarlyBinder`
Makes working with bounds lists a bit easier, which I seem to do a lot.
Specifically, means that we don't need to do `.transpose_iter().map(|(pred, _)| *pred)` every time we want to iterate through an `EarlyBinder<&'tcx [(Predicate, Span)]>` (and even then, still have to call `subst` later), which was a very awkward idiom imo.
stop using `ty::UnevaluatedConst` directly
best reviewed commit by commit.
simplifies #99798 because we now don't have to expand `ty::UnevaluatedConst` to `ty::Const`.
I also remember some other places where using `ty::UnevaluatedConst` directly was annoying and caused issues, though I don't quite remember what they were rn '^^
r? `@oli-obk` cc `@JulianKnodt`
Rollup of 6 pull requests
Successful merges:
- #102287 (Elaborate supertrait bounds when triggering `unused_must_use` on `impl Trait`)
- #102922 (Filtering spans when emitting json)
- #103051 (translation: doc comments with derives, subdiagnostic-less enum variants, more derive use)
- #103111 (Account for hygiene in typo suggestions, and use them to point to shadowed names)
- #103260 (Fixup a few tests needing asm support)
- #103321 (rustdoc: improve appearance of source page navigation bar)
Failed merges:
- #103209 (Diagnostic derives: allow specifying multiple alternative suggestions)
r? `@ghost`
`@rustbot` modify labels: rollup
Use already checked RHS ty for LHS deref suggestions
There's no reason to do the `check_lhs_assignable` and RHS `check_expr_with_hint` in that order, so invert them and use the typeck results to avoid exponential blowup on error.
Fixes#103219
Let expressions on RHS shouldn't be terminating scopes
Fixes#100276.
Before this PR, we were unconditionally marking the RHS of short-circuiting binary expressions as a terminating scope.
In the case of a let chain where the `let` expression was on the RHS, this meant that temporaries within the `let` expr would only live until the end of the expression. Since this only affected the RHS, this led to surprising behavior ([example](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=d1b0a5d1f01882f9c89c2194a75eb19f)).
After this PR, we only mark the RHS as a terminating scope if it is not a `let` expression.
Fix subst issues with return-position `impl Trait` in trait
1. Fix an issue where we were rebase impl substs onto trait method substs, instead of trait substs
2. Fix an issue where early-bound regions aren't being mapped correctly for RPITIT hidden types
Fixes#102301Fixes#102310Fixes#102334Fixes#102918
Make `dyn*` casts into a coercion, allow `dyn*` upcasting
I know that `dyn*` is likely not going to be a feature exposed to surface Rust, but this makes it slightly more ergonomic to write tests for these types anyways. ... and this was just fun to implement anyways.
1. Make `dyn*` into a coercion instead of a cast
2. Enable `dyn*` upcasting since we basically get it for free
3. Simplify some of the cast checking code since we're using the coercion path now
r? `@eholk` but feel free to reassign
cc `@nikomatsakis` and `@tmandry` who might care about making `dyn*` casts into a coercion
More dupe word typos
I only picked those changes (from the regex search) that I am pretty certain doesn't change meaning and is just a typo fix. Do correct me if any fix is undesirable and I can revert those. Thanks.
replace ReErased with fresh region vars in opaque types
See inline comments.
Prior art #102943. cc ``@compiler-errors`` ``@oli-obk``
Fixes#100267Fixes#101940Fixes#102649Fixes#102510
Support default-body trait functions with return-position `impl Trait` in traits
Introduce a new `Trait` candidate kind for the `ImplTraitInTrait` projection candidate, which just projects an RPITIT down to its opaque type form.
This is a hack until we lower RPITITs to regular associated types, after which we will need to rework how these default bodies are type-checked, so comments are left in a few places for us to clean up later.
Fixes#101665
nicer errors from assert_unsafe_precondition
This makes the errors shown by cargo-careful nicer, and since `panic_no_unwind` is `nounwind noreturn` it hopefully doesn't have bad codegen impact. Thanks to `@bjorn3` for the hint!
Would be nice if we could somehow supply our own (static) message to print, currently it always prints `panic in a function that cannot unwind`. But still, this is better than before.
Check representability in adt_sized_constraint
Now that representability is a query, we can use it to preemptively avoid a cycle in `adt_sized_constraint`.
I moved the representability check into `check_mod_type_wf` to avoid a scenario where rustc quits before checking all the types for representability. This also removes the check from rustdoc, which is alright AFAIK.
r? ``@cjgillot``
Check uniqueness of impl items by trait item when applicable.
When checking uniqueness of item names in impl blocks, we currently use the same definition of hygiene as for toplevel items. This means that a plain item and one generated by a macro 2.0 do not collide.
This hygiene rule does not match with how impl items resolve to associated trait items. As a consequence, we misdiagnose the trait impls.
This PR proposes to consider that trait impl items are uses of the corresponding trait items during resolution, instead of checking for duplicates later. An error is emitted when a trait impl item is used twice.
There should be no stable breakage, since macros 2.0 are still unstable.
r? ``@petrochenkov``
cc ``@RalfJung``
Fixes https://github.com/rust-lang/rust/issues/71614.
Move lifetime resolution module to rustc_hir_analysis.
Now that lifetime resolution has been removed from it, this file has nothing to do in `rustc_resolve`. It's purpose is to compute Debruijn indices for lifetimes, so let's put it in type collection.
rename `ImplItemKind::TyAlias` to `ImplItemKind::Type`
The naming of this variant seems inconsistent given that this is not really a "type alias", and the associated type variant for `TraitItemKind` is just called `Type`.
Rewrite representability
* Improve placement of `Box` in the suggestion
* Multiple items in a cycle emit 1 error instead of an error for each item in the cycle
* Introduce `representability` query to avoid traversing an item every time it is used.
* Also introduce `params_in_repr` query to avoid traversing generic items every time it is used.
Rollup of 6 pull requests
Successful merges:
- #102300 (Use a macro to not have to copy-paste `ConstFnMutClosure::new(&mut fold, NeverShortCircuit::wrap_mut_2_imp)).0` everywhere)
- #102475 (unsafe keyword: trait examples and unsafe_op_in_unsafe_fn update)
- #102760 (Avoid repeated re-initialization of the BufReader buffer)
- #102764 (Check `WhereClauseReferencesSelf` after all other object safety checks)
- #102779 (Fix `type_of` ICE)
- #102780 (run Miri CI when std::sys changes)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
make `compare_const_impl` a query and use it in `instance.rs`
Fixes#88365
the bug in #88365 was caused by some `instance.rs` code using the `PartialEq` impl on `Ty` to check that the type of the associated const in an impl is the same as the type of the associated const in the trait definition. This was wrong for two reasons:
- the check typeck does is that the impl type is a subtype of the trait definition's type (see `mismatched_impl_ty_2.rs` which [was ICEing](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=f6d60ebe6745011f0d52ab2bc712025d) before this PR on stable)
- it assumes that if two types are equal then the `PartialEq` impl will reflect that which isnt true for higher ranked types or type level constants when `feature(generic_const_exprs)` is enabled (see `mismatched_impl_ty_3.rs` for higher ranked types which was [ICEing on stable](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=d7af131a655ed515b035624626c62c71))
r? `@lcnr`
Suggest `==` to wrong assign expr
Given the following code:
```rust
fn main() {
let x = 3;
let y = 3;
if x == x && y = y {
println!("{}", x);
}
}
```
Current output is:
```
error[E0308]: mismatched types
--> src/main.rs:4:18
|
4 | if x == x && y = y {
| ^ expected `bool`, found integer
error[E0308]: mismatched types
--> src/main.rs:4:8
|
4 | if x == x && y = y {
| ^^^^^^^^^^^^^^^ expected `bool`, found `()`
```
This adds a suggestion:
```diff
error[E0308]: mismatched types
--> src/main.rs:6:18
|
6 | if x == x && y = y {
| ^ expected `bool`, found integer
error[E0308]: mismatched types
--> src/main.rs:6:8
|
6 | if x == x && y = y {
| ^^^^^^^^^^^^^^^ expected `bool`, found `()`
|
+ help: you might have meant to compare for equality
+ |
+ 6 | if x == x && y == y {
+ | +
```
And this fixes a part of #97469
Suggest calling method if fn does not exist
I tried to split this up into two commits, the first where we stash the resolution error until typeck (which causes a bunch of diagnostics changes because the ordering of error messages change), then the second commit is the actual logic that actually implements the suggestion.
I am not in love with the presentation of the suggestion, so I could use some advice for how to format the actual messaging.
r? diagnostics
Fixes#102518
Suggest `.into()` when all other coercion suggestions fail
Also removes some bogus suggestions because we now short-circuit when offering coercion suggestions(instead of, for example, suggesting every one that could possibly apply)
Fixes#102415
Slightly improve no return for returning function error
Fixes#100607
The rationale is that absolute beginners will be slightly confused as to why certain lines of code in a function does not require a semicolon. (I have actually witness a beginner having this confusion). Hence, a slight rationale is added "to return this value", which signals to the user that after removing said semicolon the value is returned resolving that error.
However, if this is not desirable, I welcome any other suggestions. Thanks.
Rollup of 7 pull requests
Successful merges:
- #102441 (Suggest unwrap_or_else when a closure is given)
- #102547 (Migrate CSS theme for search results)
- #102567 (Delay evaluating lint primary message until after it would be suppressed)
- #102624 (rustdoc: remove font family CSS on `.rustdoc-toggle summary::before`)
- #102628 (Change the parameter name of From::from to `value`)
- #102637 (Ignore fuchsia on two compiler tests)
- #102639 (Improve spans when splitting multi-char operator tokens for proc macros.)
Failed merges:
- #102496 (Suggest `.into()` when all other coercion suggestions fail)
r? `@ghost`
`@rustbot` modify labels: rollup
errors: rename `typeck.ftl` to `hir_analysis.ftl`
In #102306, `rustc_typeck` was renamed to `rustc_hir_analysis` but the diagnostic resources were not renamed - which is what this pull request changes.
In #102306, `rustc_typeck` was renamed to `rustc_hir_analysis` but the
diagnostic resources were not renamed - which is what this commit
changes.
Signed-off-by: David Wood <david.wood@huawei.com>
Remove `expr_parentheses_needed` from `ParseSess`
Not sure why this method needed to exist on `ParseSess`, but we can achieve the same behavior by just inlining it everywhere.
Move lint level source explanation to the bottom
So, uhhhhh
r? `@estebank`
## User-facing change
"note: `#[warn(...)]` on by default" and such are moved to the bottom of the diagnostic:
```diff
- = note: `#[warn(unsupported_calling_conventions)]` on by default
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #87678 <https://github.com/rust-lang/rust/issues/87678>
+ = note: `#[warn(unsupported_calling_conventions)]` on by default
```
Why warning is enabled is the least important thing, so it shouldn't be the first note the user reads, IMO.
## Developer-facing change
`struct_span_lint` and similar methods have a different signature.
Before: `..., impl for<'a> FnOnce(LintDiagnosticBuilder<'a, ()>)`
After: `..., impl Into<DiagnosticMessage>, impl for<'a, 'b> FnOnce(&'b mut DiagnosticBuilder<'a, ()>) -> &'b mut DiagnosticBuilder<'a, ()>`
The reason for this is that `struct_span_lint` needs to edit the diagnostic _after_ `decorate` closure is called. This also makes lint code a little bit nicer in my opinion.
Another option is to use `impl for<'a> FnOnce(LintDiagnosticBuilder<'a, ()>) -> DiagnosticBuilder<'a, ()>` altough I don't _really_ see reasons to do `let lint = lint.build(message)` everywhere.
## Subtle problem
By moving the message outside of the closure (that may not be called if the lint is disabled) `format!(...)` is executed earlier, possibly formatting `Ty` which may call a query that trims paths that crashes the compiler if there were no warnings...
I don't think it's that big of a deal, considering that we move from `format!(...)` to `fluent` (which is lazy by-default) anyway, however this required adding a workaround which is unfortunate.
## P.S.
I'm sorry, I do not how to make this PR smaller/easier to review. Changes to the lint API affect SO MUCH 😢
Split out the error reporting logic into a separate function
I was trying to read the function and got distracted by the huge block of code in the middle of it. Turns out it only reports diagnostics and all paths within it end in an error. The main function is now more readable imo.
Fix associated type bindings with anon const in GAT position
The first commit formats `type_of.rs`, which is really hard to maintain since it uses a bunch of features like `let`-chains and `if let` match arm bindings. Best if you just review the second two diffs.
Fixes#102333
`Res::SelfTy` currently has two `Option`s. When the second one is `Some`
the first one is never consulted. So we can split it into two variants,
`Res::SelfTyParam` and `Res::SelfTyAlias`, reducing the size of `Res`
from 24 bytes to 12. This then shrinks `hir::Path` and
`hir::PathSegment`, which are the HIR types that take up the most space.
Add `#[rustc_safe_intrinsic]`
This PR adds the `#[rustc_safe_intrinsic]` attribute as mentionned on Zulip. The goal of this attribute is to avoid keeping a list of symbols as the source for stable intrinsics, and instead rely on an attribute. This is similar to `#[rustc_const_stable]` and `#[rustc_const_unstable]`, which among other things, are used to mark the constness of intrinsic functions.
Do not overwrite lifetime binders for another HirId.
This PR makes higher-ranked bounds in where clauses a bit more principled.
We used to conflate `for<'a> T: Trait` with `(for<'a> T): Trait`.
This PR separates both binders.
This caused issued with fn types, which have their own binder, causing us to overwrite the predicates's binders with `fn`'s binders, ICEing.
Fixes https://github.com/rust-lang/rust/issues/98594
Deny associated type bindings within associated type bindings
Fixes#102335
This was made worse by #100865, which unified the way we generate substs for GATs and non-generic associated types. However, the issue was not _caused_ by #100865, evidenced by the test I added for GATs:
```rust
trait T {
type A: S<C<(), i32 = ()> = ()>;
//~^ ERROR associated type bindings are not allowed here
}
trait Q {}
trait S {
type C<T>: Q;
}
fn main() {}
```
^ which passes on beta (where GATs are stable) and presumably ever since GATs support was added to `create_substs_for_associated_item` in astconv.
