Switch to `EarlyBinder` for `type_of` query
Part of the work to finish #105779 and implement https://github.com/rust-lang/types-team/issues/78.
Several queries `X` have a `bound_X` variant that wraps the output in `EarlyBinder`. This adds `EarlyBinder` to the return type of the `type_of` query and removes `bound_type_of`.
r? `@lcnr`
Implement partial support for non-lifetime binders
This implements support for non-lifetime binders. It's pretty useless currently, but I wanted to put this up so the implementation can be discussed.
Specifically, this piggybacks off of the late-bound lifetime collection code in `rustc_hir_typeck::collect::lifetimes`. This seems like a necessary step given the fact we don't resolve late-bound regions until this point, and binders are sometimes merged.
Q: I'm not sure if I should go along this route, or try to modify the earlier nameres code to compute the right bound var indices for type and const binders eagerly... If so, I'll need to rename all these queries to something more appropriate (I've done this for `resolve_lifetime::Region` -> `resolve_lifetime::ResolvedArg`)
cc rust-lang/types-team#81
r? `@ghost`
don't point at nonexisting code beyond EOF when warning about delims
Previously we would show this:
```
warning: unnecessary braces around block return value
--> /tmp/bad.rs:1:8
|
1 | fn a(){{{
| ^ ^
|
= note: `#[warn(unused_braces)]` on by default
help: remove these braces
|
1 - fn a(){{{
1 + fn a(){{
|
```
which is now hidden in this case.
We would create a span spanning between the pair of redundant {}s but there is only EOF instead of the `}` so we would previously point at nothing. This would cause the debug assertion ice to trigger. I would have loved to just only point at the second delim and say "you can remove that" but I'm not sure how to do that without refactoring the entire diagnostic which seems tricky. :( But given that this does not seem to regress any other tests we have, I think this edge-casey enough be acceptable.
Fixes https://github.com/rust-lang/rust/issues/107423
r? `@compiler-errors`
Previously we would show this:
```
warning: unnecessary braces around block return value
--> /tmp/bad.rs:1:8
|
1 | fn a(){{{
| ^ ^
|
= note: `#[warn(unused_braces)]` on by default
help: remove these braces
|
1 - fn a(){{{
1 + fn a(){{
|
```
which is now hidden in this case.
We would create a span spanning between the pair of redundant {}s but there is only EOF instead of the `}` so we would previously point at nothing.
This would cause the debug assertion ice to trigger.
I would have loved to just only point at the second delim and say "you can remove that" but I'm not sure how to do that without refactoring the entire diagnostic which seems tricky. :(
But given that this does not seem to regress any other tests we have, I think this edge-casey enough be acceptable.
Fixes https://github.com/rust-lang/rust/issues/107423
r? @compiler-errors
Emit warnings on unused parens in index expressions
Fixes: #96606.
I am not sure what the best term for "index expression" is. Is there a better term we could use?
Currently, deriving on packed structs has some non-trivial limitations,
related to the fact that taking references on unaligned fields is UB.
The current approach to field accesses in derived code:
- Normal case: `&self.0`
- In a packed struct that derives `Copy`: `&{self.0}`
- In a packed struct that doesn't derive `Copy`: `&self.0`
Plus, we disallow deriving any builtin traits other than `Default` for any
packed generic type, because it's possible that there might be
misaligned fields. This is a fairly broad restriction.
Plus, we disallow deriving any builtin traits other than `Default` for most
packed types that don't derive `Copy`. (The exceptions are those where the
alignments inherently satisfy the packing, e.g. in a type with
`repr(packed(N))` where all the fields have alignments of `N` or less
anyway. Such types are pretty strange, because the `packed` attribute is
not having any effect.)
This commit introduces a new, simpler approach to field accesses:
- Normal case: `&self.0`
- In a packed struct: `&{self.0}`
In the latter case, this requires that all fields impl `Copy`, which is
a new restriction. This means that the following example compiles under
the old approach and doesn't compile under the new approach.
```
#[derive(Debug)]
struct NonCopy(u8);
#[derive(Debug)
#[repr(packed)]
struct MyType(NonCopy);
```
(Note that the old approach's support for cases like this was brittle.
Changing the `u8` to a `u16` would be enough to stop it working. So not
much capability is lost here.)
However, the other constraints from the old rules are removed. We can now
derive builtin traits for packed generic structs like this:
```
trait Trait { type A; }
#[derive(Hash)]
#[repr(packed)]
pub struct Foo<T: Trait>(T, T::A);
```
To allow this, we add a `T: Copy` bound in the derived impl and a `T::A:
Copy` bound in where clauses. So `T` and `T::A` must impl `Copy`.
We can now also derive builtin traits for packed structs that don't derive
`Copy`, so long as the fields impl `Copy`:
```
#[derive(Hash)]
#[repr(packed)]
pub struct Foo(u32);
```
This includes types that hand-impl `Copy` rather than deriving it, such as the
following, that show up in winapi-0.2:
```
#[derive(Clone)]
#[repr(packed)]
struct MyType(i32);
impl Copy for MyType {}
```
The new approach is simpler to understand and implement, and it avoids
the need for the `unsafe_derive_on_repr_packed` check.
One exception is required for backwards-compatibility: we allow `[u8]`
fields for now. There is a new lint for this,
`byte_slice_in_packed_struct_with_derive`.
Skip possible where_clause_object_safety lints when checking `multiple_supertrait_upcastable`
Fix#106247
To achieve this, I lifted the `WhereClauseReferencesSelf` out from `object_safety_violations` and move it into `is_object_safe` (which is changed to a new query).
cc `@dtolnay`
r? `@compiler-errors`
Remove HirId -> LocalDefId map from HIR.
Having this map in HIR prevents the creating of new definitions after HIR has been built.
Thankfully, we do not need it.
Based on https://github.com/rust-lang/rust/pull/103902
Remove overlapping parts of multipart suggestions
This PR adds a debug assertion that the parts of a single substitution cannot overlap, fixes a overlapping substitution from the testsuite, and fixes https://github.com/rust-lang/rust/issues/106870.
Note that a single suggestion can still have multiple overlapping substitutions / possible edits, we just don't suggest overlapping replacements in a single edit anymore.
I've also included a fix for an unrelated bug where rustfix for `explicit_outlives_requirements` would produce multiple trailing commas for a where clause.
use LocalDefId instead of HirId in trait resolution to simplify
the obligation clause resolution
Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Switching them to `Break(())` and `Continue(())` instead.
libs-api would like to remove these constants, so stop using them in compiler to make the removal PR later smaller.
Migrate `rustc_lint` lint diagnostics
Part 2 of [Migrate `rustc_lint` errors to `SessionDiagnostic`](https://github.com/rust-lang/rust/pull/100776)
r? `@davidtwco`
# TODO
- [x] Refactor some lints manually implementing `DecorateLint` to use `Option<Subdiagnostic>`.
- [x] Add `#[rustc_lint_diagnostics]` to lint functions in `context.rs`.
- [x] Migrate `hidden_unicode_codepoints.rs`.
- [x] Migrate `UnsafeCode` in `builtin.rs`.
- [x] Migrate the rest of `builtin.rs`.
Fix stack overflow in recursive AST walk in early lint
The src/test/ui/issues/issue-74564-if-expr-stack-overflow.rs test case added to verify https://github.com/rust-lang/rust/issues/74564 still crashes with a stack overflow on s390x-ibm-linux.
Symptom is a very deep recursion in compiler/rustc_lint/src/early.rs:
fn visit_expr(&mut self, e: &'a ast::Expr) {
self.with_lint_attrs(e.id, &e.attrs, |cx| {
lint_callback!(cx, check_expr, e);
ast_visit::walk_expr(cx, e);
})
}
(where walk_expr recursively calls back into visit_expr). The crash happens at a nesting depth of over 17000 stack frames when using the default 8 MB stack size on s390x.
This patch fixes the problem by adding a ensure_sufficient_stack call to the with_lint_attrs routine (which also should take care of all the other mutually recursive visitors here).
Fixes part of https://github.com/rust-lang/rust/issues/105383.
Rename `hir::Map::{get_,find_}parent_node` to `hir::Map::{,opt_}parent_id`, and add `hir::Map::{get,find}_parent`
The `hir::Map::get_parent_node` function doesn't return a `Node`, and I think that's quite confusing. Let's rename it to something that sounds more like something that gets the parent hir id => `hir::Map::parent_id`. Same with `find_parent_node` => `opt_parent_id`.
Also, combine `hir.get(hir.parent_id(hir_id))` and similar `hir.find(hir.parent_id(hir_id))` function into new functions that actually retrieve the parent node in one call. This last commit is the only one that might need to be looked at closely.
Revert "Implement allow-by-default `multiple_supertrait_upcastable` lint"
This is a clean revert of #105484.
I confirmed that reverting that PR fixes the regression reported in #106247. ~~I can't say I understand what this code is doing, but maybe it can be re-landed with a different implementation.~~ **Edit:** https://github.com/rust-lang/rust/issues/106247#issuecomment-1367174384 has an explanation of why #105484 ends up surfacing spurious `where_clause_object_safety` errors. The implementation of `where_clause_object_safety` assumes we only check whether a trait is object safe when somebody actually uses that trait with `dyn`. However the implementation of `multiple_supertrait_upcastable` added in the problematic PR involves checking *every* trait for whether it is object-safe.
FYI `@nbdd0121` `@compiler-errors`
Implement allow-by-default `multiple_supertrait_upcastable` lint
The lint detects when an object-safe trait has multiple supertraits.
Enabled in libcore and liballoc as they are low-level enough that many embedded programs will use them.
r? `@nikomatsakis`
Switch `#[track_caller]` back to a no-op unless feature gate is enabled
This patch fixes a regression, in which `#[track_caller]`, which was previously a no-op, was changed to actually turn on the behavior. This should instead only happen behind the `closure_track_caller` feature gate.
Also, add a warning for the user to understand how their code will compile depending on the feature gate being turned on or not.
Fixes#104588
Sort lint_groups in no_lint_suggestion
The no_lint_suggestion routine passes a vector of lint group names to find_best_match_for_name. That routine depends on the sort order of its input vector, which matters in case multiple inputs are at the same Levenshtein distance to the target name.
However, no_lint_suggestion currently just passes lint_groups.keys() as input vector - this is sorted in hash value order, which is not guaranteed to be stable, and in fact differs between big- and little-endian host platforms, causing test failures on s390x.
To fix this, always sort the lint groups before using their names as input to find_best_match_for_name. In doing so, prefer non- deprecated lint group names over deprecated ones, and then use alphabetical order.
Fixes https://github.com/rust-lang/rust/issues/105379
The no_lint_suggestion routine passes a vector of lint group names
to find_best_match_for_name. That routine depends on the sort
order of its input vector, which matters in case multiple inputs
are at the same Levenshtein distance to the target name.
However, no_lint_suggestion currently just passes lint_groups.keys()
as input vector - this is sorted in hash value order, which is not
guaranteed to be stable, and in fact differs between big- and
little-endian host platforms, causing test failures on s390x.
To fix this, always sort the lint groups before using their names
as input to find_best_match_for_name. In addition, deprecated
lint groups should never be suggested, so filter those out.
Fixes https://github.com/rust-lang/rust/issues/105379
This patch does the following:
- Refactor some repeated lines into a single one
- Split the `ungated_async_fn_caller` lint into multiple lines, and make
one of those lines only print out on nightly
- Use test revisions instead of copying an existing test
This patch fixes a regression, in which `#[track_caller]`, which was
previously a no-op, was changed to actually turn on the behavior. This
should instead only happen behind the `closure_track_caller` feature
gate.
Also, add a warning for the user to understand how their code will
compile depending on the feature gate being turned on or not.
Fixes#104588
Improve syntax of `newtype_index`
This makes it more like proper Rust and also makes the implementation a lot simpler.
Mostly just turns weird flags in the body into proper attributes.
It should probably also be converted to an attribute macro instead of function-like, but that can be done in a future PR.
The src/test/ui/issues/issue-74564-if-expr-stack-overflow.rs test case
added to verify https://github.com/rust-lang/rust/issues/74564 still
crashes with a stack overflow on s390x-ibm-linux.
Symptom is a very deep recursion in compiler/rustc_lint/src/early.rs:
fn visit_expr(&mut self, e: &'a ast::Expr) {
self.with_lint_attrs(e.id, &e.attrs, |cx| {
lint_callback!(cx, check_expr, e);
ast_visit::walk_expr(cx, e);
})
}
(where walk_expr recursively calls back into visit_expr). The crash
happens at a nesting depth of over 17000 stack frames when using the
default 8 MB stack size on s390x.
This patch fixes the problem by adding a ensure_sufficient_stack
call to the with_lint_attrs routine (which also should take care
of all the other mutually recursive visitors here).
Fixes part of https://github.com/rust-lang/rust/issues/105383.
Remove the `..` from the body, only a few invocations used it and it's
inconsistent with rust syntax.
Use `;` instead of `,` between consts. As the Rust syntax gods inteded.
This commit partly undoes #104863, which combined the builtin lints pass
with other lints. This caused a slowdown, because often there are no
other lints, and it's faster to do a pass with a single lint directly
than it is to do a combined pass with a `passes` vector containing a
single lint.
I removed these in #105291, and subsequently learned they are necessary
for performance.
This commit reinstates them with the new and more descriptive names
`RuntimeCombined{Early,Late}LintPass`, similar to the existing passes
like `BuiltinCombinedEarlyLintPass`. It also adds some comments,
particularly emphasising how we have ways to combine passes at both
compile-time and runtime. And it moves some comments around.
compiler: remove unnecessary imports and qualified paths
Some of these imports were necessary before Edition 2021, others were already in the prelude.
I hope it's fine that this PR is so spread-out across files :/
Make `missing_copy_implementations` more cautious
- Fixes https://github.com/rust-lang/rust/issues/98348
- Also makes the lint not fire on large types and types containing raw pointers. Thoughts?
Remove `{Early,Late}LintPassObjects`.
`EarlyContextAndPass` wraps a single early lint pass. We aggregate multiple passes into that single pass by using `EarlyLintPassObjects`.
This commit removes `EarlyLintPassObjects` by changing `EarlyContextAndPass` into `EarlyContextAndPasses`. I.e. it just removes a level of indirection. This makes the code simpler and slightly faster.
The commit does likewise for late lints.
r? `@cjgillot`
Put all cached values into a central struct instead of just the stable hash
cc `@nnethercote`
this allows re-use of the type for Predicate without duplicating all the logic for the non-hash cached fields
`EarlyContextAndPass` wraps a single early lint pass. We aggregate
multiple passes into that single pass by using `EarlyLintPassObjects`.
This commit removes `EarlyLintPassObjects` by changing
`EarlyContextAndPass` into `EarlyContextAndPasses`. I.e. it just removes
a level of indirection. This makes the code simpler and slightly faster.
The commit does likewise for late lints.
This avoids calling `early_lint_node` twice.
Note: one `early_lint_node` call had `!pre_expansion` for the second
argument and the other had `false`. The new single call just has
`!pre_expansion`. This results in a reduction of duplicate error
messages in some `ui-fulldeps` tests. The order of some `ui-fulldeps`
output also changes, but that doesn't matter.
The lint definitions use macros heavily. This commit merges some of them
that are split unnecessarily. I find the reduced indirection makes it
easier to imagine what the generated code will look like.
Lower them into a single item with multiple resolutions instead.
This also allows to remove additional `NodId`s and `DefId`s related to those additional items.
Prefer doc comments over `//`-comments in compiler
Doc comments are generally nicer: they show up in the documentation, they are shown in IDEs when you hover other mentions of items, etc. Thus it makes sense to use them instead of `//`-comments.
Separate lifetime ident from lifetime resolution in HIR
Drive-by: change how suggested generic args are computed.
Fixes https://github.com/rust-lang/rust/issues/103815
I recommend reviewing commit-by-commit.
Make rustc_target usable outside of rustc
I'm working on showing type size in rust-analyzer (https://github.com/rust-lang/rust-analyzer/pull/13490) and I currently copied rustc code inside rust-analyzer, which works, but is bad. With this change, I would become able to use `rustc_target` and `rustc_index` directly in r-a, reducing the amount of copy needed.
This PR contains some feature flag to put nightly features behind them to make crates buildable on the stable compiler + makes layout related types generic over index type + removes interning of nested layouts.
Avoid `GenFuture` shim when compiling async constructs
Previously, async constructs would be lowered to "normal" generators, with an additional `from_generator` / `GenFuture` shim in between to convert from `Generator` to `Future`.
The compiler will now special-case these generators internally so that async constructs will *directly* implement `Future` without the need to go through the `from_generator` / `GenFuture` shim.
The primary motivation for this change was hiding this implementation detail in stack traces and debuginfo, but it can in theory also help the optimizer as there is less abstractions to see through.
---
Given this demo code:
```rust
pub async fn a(arg: u32) -> Backtrace {
let bt = b().await;
let _arg = arg;
bt
}
pub async fn b() -> Backtrace {
Backtrace::force_capture()
}
```
I would get the following with the latest stable compiler (on Windows):
```
4: async_codegen:🅱️:async_fn$0
at .\src\lib.rs:10
5: core::future::from_generator::impl$1::poll<enum2$<async_codegen:🅱️:async_fn_env$0> >
at /rustc/897e37553bba8b42751c67658967889d11ecd120\library\core\src\future\mod.rs:91
6: async_codegen:🅰️:async_fn$0
at .\src\lib.rs:4
7: core::future::from_generator::impl$1::poll<enum2$<async_codegen:🅰️:async_fn_env$0> >
at /rustc/897e37553bba8b42751c67658967889d11ecd120\library\core\src\future\mod.rs:91
```
whereas now I get a much cleaner stack trace:
```
3: async_codegen:🅱️:async_fn$0
at .\src\lib.rs:10
4: async_codegen:🅰️:async_fn$0
at .\src\lib.rs:4
```
Previously, async constructs would be lowered to "normal" generators,
with an additional `from_generator` / `GenFuture` shim in between to
convert from `Generator` to `Future`.
The compiler will now special-case these generators internally so that
async constructs will *directly* implement `Future` without the need
to go through the `from_generator` / `GenFuture` shim.
The primary motivation for this change was hiding this implementation
detail in stack traces and debuginfo, but it can in theory also help
the optimizer as there is less abstractions to see through.
Refactor must_use lint into two parts
Before, the lint did the checking for `must_use` and pretty printing the types in a special format in one pass, causing quite complex and untranslatable code.
Now the collection and printing is split in two. That should also make it easier to translate or extract the type pretty printing in the future.
Also fixes an integer overflow in the array length pluralization
calculation.
fixes#104352
Rollup of 11 pull requests
Successful merges:
- #103396 (Pin::new_unchecked: discuss pinning closure captures)
- #104416 (Fix using `include_bytes` in pattern position)
- #104557 (Add a test case for async dyn* traits)
- #104559 (Split `MacArgs` in two.)
- #104597 (Probe + better error messsage for `need_migrate_deref_output_trait_object`)
- #104656 (Move tests)
- #104657 (Do not check transmute if has non region infer)
- #104663 (rustdoc: factor out common button CSS)
- #104666 (Migrate alias search result to CSS variables)
- #104674 (Make negative_impl and negative_impl_exists take the right types)
- #104692 (Update test's cfg-if dependency to 1.0)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
`MacArgs` is an enum with three variants: `Empty`, `Delimited`, and `Eq`. It's
used in two ways:
- For representing attribute macro arguments (e.g. in `AttrItem`), where all
three variants are used.
- For representing function-like macros (e.g. in `MacCall` and `MacroDef`),
where only the `Delimited` variant is used.
In other words, `MacArgs` is used in two quite different places due to them
having partial overlap. I find this makes the code hard to read. It also leads
to various unreachable code paths, and allows invalid values (such as
accidentally using `MacArgs::Empty` in a `MacCall`).
This commit splits `MacArgs` in two:
- `DelimArgs` is a new struct just for the "delimited arguments" case. It is
now used in `MacCall` and `MacroDef`.
- `AttrArgs` is a renaming of the old `MacArgs` enum for the attribute macro
case. Its `Delimited` variant now contains a `DelimArgs`.
Various other related things are renamed as well.
These changes make the code clearer, avoids several unreachable paths, and
disallows the invalid values.
Add `PolyExistentialPredicate` type alias
Wrapping `ExistentialPredicate`s in a binder is very common, and this alias already exists for the `PolyExistential{TraitRef,Projection}` types.
Before, the lint did the checking for `must_use` and pretty printing the
types in a special format in one pass, causing quite complex and
untranslatable code.
Now the collection and printing is split in two. That should also make
it easier to translate or extract the type pretty printing in the
future.
Also fixes an integer overflow in the array length pluralization
calculation.
Convert predicates into Predicate in the Obligation constructor
instead of having almost all callers do that.
This reduces a bit of boilerplate, and also paves the way for my work towards https://github.com/rust-lang/compiler-team/issues/531 (as it makes it easier to accept both goals and clauses where right now it only accepts predicates).
Record `LocalDefId` in HIR nodes instead of a side table
This is part of an attempt to remove the `HirId -> LocalDefId` table from HIR.
This attempt is a prerequisite to creation of `LocalDefId` after HIR lowering (https://github.com/rust-lang/rust/pull/96840), by controlling how `def_id` information is accessed.
This first part adds the information to HIR nodes themselves instead of a table.
The second part is https://github.com/rust-lang/rust/pull/103902
The third part will be to make `hir::Visitor::visit_fn` take a `LocalDefId` as last parameter.
The fourth part will be to completely remove the side table.
Use `token::Lit` in `ast::ExprKind::Lit`.
Instead of `ast::Lit`.
Literal lowering now happens at two different times. Expression literals are lowered when HIR is crated. Attribute literals are lowered during parsing.
r? `@petrochenkov`
Instead of `ast::Lit`.
Literal lowering now happens at two different times. Expression literals
are lowered when HIR is crated. Attribute literals are lowered during
parsing.
This commit changes the language very slightly. Some programs that used
to not compile now will compile. This is because some invalid literals
that are removed by `cfg` or attribute macros will no longer trigger
errors. See this comment for more details:
https://github.com/rust-lang/rust/pull/102944#issuecomment-1277476773
Walk types more carefully in `ProhibitOpaqueTypes` visitor
The visitor didn't account for the case where you could have `<TAIT as Trait>::Assoc` normalize to itself, in the case of a `type TAIT = impl Trait` with an unconstrained associated type. That causes the visitor to loop on the same type over and over.
Fixes#104291
Resolve lifetimes independently for each item-like.
Now that the heavy-lifting is done on the AST and during lowering, we do not need to perform HIR lifetime resolution on a full item at once. Instead, we can treat each item-like independently, and look at `generics_of` the parent exceptionally for associated items.
No longer lint against `#[must_use] async fn foo()`.
When encountering a statement that awaits on a `Future`, check if the
`Future`'s parent item is annotated with `#[must_use]` and emit a lint
if so. This effectively makes `must_use` an annotation on the
`Future::Output` instead of only the `Future` itself.
Fix#78149.
fix: lint against the functions `LintContext::{lookup_with_diagnostics,lookup,struct_span_lint,lint}`, `TyCtxt::struct_lint_node`, `LintLevelsBuilder::struct_lint`.
