Initial implementation of dyn*
This PR adds extremely basic and incomplete support for [dyn*](https://smallcultfollowing.com/babysteps//blog/2022/03/29/dyn-can-we-make-dyn-sized/). The goal is to get something in tree behind a flag to make collaboration easier, and also to make sure the implementation so far is not unreasonable. This PR does quite a few things:
* Introduce `dyn_star` feature flag
* Adds parsing for `dyn* Trait` types
* Defines `dyn* Trait` as a sized type
* Adds support for explicit casts, like `42usize as dyn* Debug`
* Including const evaluation of such casts
* Adds codegen for drop glue so things are cleaned up properly when a `dyn* Trait` object goes out of scope
* Adds codegen for method calls, at least for methods that take `&self`
Quite a bit is still missing, but this gives us a starting point. Note that this is never intended to become stable surface syntax for Rust, but rather `dyn*` is planned to be used as an implementation detail for async functions in dyn traits.
Joint work with `@nikomatsakis` and `@compiler-errors.`
r? `@bjorn3`
This shrinks `hir::Ty` from 72 to 48 bytes.
`visit_lifetime` is added to the HIR stats collector because these types
are now stored in memory on their own, instead of being within other
types.
`BindingAnnotation` refactor
* `ast::BindingMode` is deleted and replaced with `hir::BindingAnnotation` (which is moved to `ast`)
* `BindingAnnotation` is changed from an enum to a tuple struct e.g. `BindingAnnotation(ByRef::No, Mutability::Mut)`
* Associated constants added for convenience `BindingAnnotation::{NONE, REF, MUT, REF_MUT}`
One goal is to make it more clear that `BindingAnnotation` merely represents syntax `ref mut` and not the actual binding mode. This was especially confusing since we had `ast::BindingMode`->`hir::BindingAnnotation`->`thir::BindingMode`.
I wish there were more symmetry between `ByRef` and `Mutability` (variant) naming (maybe `Mutable::Yes`?), and I also don't love how long the name `BindingAnnotation` is, but this seems like the best compromise. Ideas welcome.
From 72 bytes to 12 bytes (on x86-64).
There are two parts to this:
- Changing various source code offsets from 64-bit to 32-bit. This is
not a problem because the rest of rustc also uses 32-bit source code
offsets. This means `Token` is no longer `Copy` but this causes no
problems.
- Removing the `RawStrError` from `LiteralKind`. Raw string literal
invalidity is now indicated by a `None` value within
`RawStr`/`RawByteStr`, and the new `validate_raw_str` function can be
used to re-lex an invalid raw string literal to get the `RawStrError`.
There is one very small change in behaviour. Previously, if a raw string
literal matched both the `InvalidStarter` and `TooManyHashes` cases,
the latter would override the former. This has now changed, because
`raw_double_quoted_string` now uses `?` and so returns immediately upon
detecting the `InvalidStarter` case. I think this is a slight
improvement to report the earlier-detected error, and it explains the
change in the `test_too_many_hashes` test.
The commit also removes a couple of comments that refer to #77629 and
say that the size of these types don't affect performance. These
comments are wrong, though the performance effect is small.
Implement `for<>` lifetime binder for closures
This PR implements RFC 3216 ([TI](https://github.com/rust-lang/rust/issues/97362)) and allows code like the following:
```rust
let _f = for<'a, 'b> |a: &'a A, b: &'b B| -> &'b C { b.c(a) };
// ^^^^^^^^^^^--- new!
```
cc ``@Aaron1011`` ``@cjgillot``
once cell renamings
This PR does the renamings proposed in https://github.com/rust-lang/rust/issues/74465#issuecomment-1153703128
- Move/rename `lazy::{OnceCell, Lazy}` to `cell::{OnceCell, LazyCell}`
- Move/rename `lazy::{SyncOnceCell, SyncLazy}` to `sync::{OnceLock, LazyLock}`
(I used `Lazy...` instead of `...Lazy` as it seems to be more consistent, easier to pronounce, etc)
```@rustbot``` label +T-libs-api -T-libs
Make `ExprKind::Closure` a struct variant.
Simple refactor since we both need it to introduce additional fields in `ExprKind::Closure`.
r? ``@Aaron1011``
And likewise for the `Const::val` method.
Because its type is called `ConstKind`. Also `val` is a confusing name
because `ConstKind` is an enum with seven variants, one of which is
called `Value`. Also, this gives consistency with `TyS` and `PredicateS`
which have `kind` fields.
The commit also renames a few `Const` variables from `val` to `c`, to
avoid confusion with the `ConstKind::Value` variant.
Compute `is_late_bound_map` query separately from lifetime resolution
This query is actually very simple, and is only useful for functions and method. It can be computed directly by fetching the HIR, with no need to embed it within the lifetime resolution visitor.
Based on https://github.com/rust-lang/rust/pull/96296
Lazify `SourceFile::lines`.
`SourceFile::lines` is a big part of metadata. It's stored in a compressed form
(a difference list) to save disk space. Decoding it is a big fraction of
compile time for very small crates/programs.
This commit introduces a new type `SourceFileLines` which has a `Lines`
form and a `Diffs` form. The latter is used when the metadata is first
read, and it is only decoded into the `Lines` form when line data is
actually needed. This avoids the decoding cost for many files,
especially in `std`. It's a performance win of up to 15% for tiny
crates/programs where metadata decoding is a high part of compilation
costs.
A `RefCell` is needed because the methods that access lines data (which can
trigger decoding) take `&self` rather than `&mut self`. To allow for this,
`SourceFile::lines` now takes a `FnMut` that operates on the lines slice rather
than returning the lines slice.
r? `@Mark-Simulacrum`
`SourceFile::lines` is a big part of metadata. It's stored in a compressed form
(a difference list) to save disk space. Decoding it is a big fraction of
compile time for very small crates/programs.
This commit introduces a new type `SourceFileLines` which has a `Lines`
form and a `Diffs` form. The latter is used when the metadata is first
read, and it is only decoded into the `Lines` form when line data is
actually needed. This avoids the decoding cost for many files,
especially in `std`. It's a performance win of up to 15% for tiny
crates/programs where metadata decoding is a high part of compilation
costs.
A `Lock` is needed because the methods that access lines data (which can
trigger decoding) take `&self` rather than `&mut self`. To allow for this,
`SourceFile::lines` now takes a `FnMut` that operates on the lines slice rather
than returning the lines slice.
Refactor call terminator to always include destination place
In #71117 people seemed to agree that call terminators should always have a destination place, even if the call was guaranteed to diverge. This implements that. Unsurprisingly, the diff touches a lot of code, but thankfully I had to do almost nothing interesting. The only interesting thing came up in const prop, where the stack frame having no return place was also used to indicate that the layout could not be computed (or similar). I replaced this with a ZST allocation, which should continue to do the right things.
cc `@RalfJung` `@eddyb` who were involved in the original conversation
r? rust-lang/mir-opt
Lifetime variance fixes for clippy
#97287 migrates rustc to a `Ty` type that is invariant over its lifetime `'tcx`, so I need to fix a bunch of places that assume that `Ty<'a>` and `Ty<'b>` can be shortened to some common lifetime.
This is doable, since everything is already `'tcx`, so all this PR does is be a bit more explicit that elided lifetimes are actually `'tcx`.
Split out from #97287 so the clippy team can review independently.
Drop Tracking: Implement `fake_read` callback
This PR updates drop tracking's use of `ExprUseVisitor` so that we treat `fake_read` events as borrows. Without doing this, we were not handling match expressions correctly, which showed up as a breakage in the `addassign-yield.rs` test. We did not previously notice this because we still had rather large temporary scopes that we held borrows for, which changed in #94309.
This PR also includes a variant of the `addassign-yield.rs` test case to make sure we continue to have correct behavior here with drop tracking.
r? `@nikomatsakis`
Add a query for checking whether a function is an intrinsic.
work towards #93145
This will reduce churn when we add more ways to declare intrinsics
r? `@scottmcm`
Add EarlyBinder
Chalk has no concept of `Param` (e0ade19d13/chalk-ir/src/lib.rs (L579)) or `ReEarlyBound` (e0ade19d13/chalk-ir/src/lib.rs (L1308)). Everything is just "bound" - the equivalent of rustc's late-bound. It's not completely clear yet whether to move everything to the same time of binder in rustc or add `Param` and `ReEarlyBound` in Chalk.
Either way, tracking when we have or haven't already substituted out these in rustc can be helpful.
As a first step, I'm just adding a `EarlyBinder` newtype that is required to call `subst`. I also add a couple "transparent" `bound_*` wrappers around a couple query that are often immediately substituted.
r? `@nikomatsakis`
Overhaul `MacArgs`
Motivation:
- Clarify some code that I found hard to understand.
- Eliminate one use of three places where `TokenKind::Interpolated` values are created.
r? `@petrochenkov`
The value in `MacArgs::Eq` is currently represented as a `Token`.
Because of `TokenKind::Interpolated`, `Token` can be either a token or
an arbitrary AST fragment. In practice, a `MacArgs::Eq` starts out as a
literal or macro call AST fragment, and then is later lowered to a
literal token. But this is very non-obvious. `Token` is a much more
general type than what is needed.
This commit restricts things, by introducing a new type `MacArgsEqKind`
that is either an AST expression (pre-lowering) or an AST literal
(post-lowering). The downside is that the code is a bit more verbose in
a few places. The benefit is that makes it much clearer what the
possibilities are (though also shorter in some other places). Also, it
removes one use of `TokenKind::Interpolated`, taking us a step closer to
removing that variant, which will let us make `Token` impl `Copy` and
remove many "handle Interpolated" code paths in the parser.
Things to note:
- Error messages have improved. Messages like this:
```
unexpected token: `"bug" + "found"`
```
now say "unexpected expression", which makes more sense. Although
arbitrary expressions can exist within tokens thanks to
`TokenKind::Interpolated`, that's not obvious to anyone who doesn't
know compiler internals.
- In `parse_mac_args_common`, we no longer need to collect tokens for
the value expression.
Only crate root def-ids don't have a parent, and in majority of cases the argument of `DefIdTree::parent` cannot be a crate root.
So we now panic by default in `parent` and introduce a new non-panicing function `opt_parent` for cases where the argument can be a crate root.
Same applies to `local_parent`/`opt_local_parent`.
Implement sym operands for global_asm!
Tracking issue: #93333
This PR is pretty much a complete rewrite of `sym` operand support for inline assembly so that the same implementation can be shared by `asm!` and `global_asm!`. The main changes are:
- At the AST level, `sym` is represented as a special `InlineAsmSym` AST node containing a path instead of an `Expr`.
- At the HIR level, `sym` is split into `SymStatic` and `SymFn` depending on whether the path resolves to a static during AST lowering (defaults to `SynFn` if `get_early_res` fails).
- `SymFn` is just an `AnonConst`. It runs through typeck and we just collect the resulting type at the end. An error is emitted if the type is not a `FnDef`.
- `SymStatic` directly holds a path and the `DefId` of the `static` that it is pointing to.
- The representation at the MIR level is mostly unchanged. There is a minor change to THIR where `SymFn` is a constant instead of an expression.
- At the codegen level we need to apply the target's symbol mangling to the result of `tcx.symbol_name()` depending on the target. This is done by calling the LLVM name mangler, which handles all of the details.
- On Mach-O, all symbols have a leading underscore.
- On x86 Windows, different mangling is used for cdecl, stdcall, fastcall and vectorcall.
- No mangling is needed on other platforms.
r? `@nagisa`
cc `@eddyb`
Use mir constant in thir instead of ty::Const
This is blocked on https://github.com/rust-lang/rust/pull/94059 (does include its changes, the first two commits in this PR correspond to those changes) and https://github.com/rust-lang/rust/pull/93800 being reinstated (which had to be reverted). Mainly opening since `@lcnr` offered to give some feedback and maybe also for a perf-run (if necessary).
This currently contains a lot of duplication since some of the logic of `ty::Const` had to be copied to `mir::ConstantKind`, but with the introduction of valtrees a lot of that functionality will disappear from `ty::Const`.
Only the last commit contains changes that need to be reviewed here. Did leave some `FIXME` comments regarding future implementation decisions and some things that might be incorrectly implemented.
r? `@oli-obk`
`MultiSpan` contains labels, which are more complicated with the
introduction of diagnostic translation and will use types from
`rustc_errors` - however, `rustc_errors` depends on `rustc_span` so
`rustc_span` cannot use types like `DiagnosticMessage` without
dependency cycles. Introduce a new `rustc_error_messages` crate that can
contain `DiagnosticMessage` and `MultiSpan`.
Signed-off-by: David Wood <david.wood@huawei.com>
This commit makes `AdtDef` use `Interned`. Much the commit is tedious
changes to introduce getter functions. The interesting changes are in
`compiler/rustc_middle/src/ty/adt.rs`.
Currently some `Allocation`s are interned, some are not, and it's very
hard to tell at a use point which is which.
This commit introduces `ConstAllocation` for the known-interned ones,
which makes the division much clearer. `ConstAllocation::inner()` is
used to get the underlying `Allocation`.
In some places it's natural to use an `Allocation`, in some it's natural
to use a `ConstAllocation`, and in some places there's no clear choice.
I've tried to make things look as nice as possible, while generally
favouring `ConstAllocation`, which is the type that embodies more
information. This does require quite a few calls to `inner()`.
The commit also tweaks how `PartialOrd` works for `Interned`. The
previous code was too clever by half, building on `T: Ord` to make the
code shorter. That caused problems with deriving `PartialOrd` and `Ord`
for `ConstAllocation`, so I changed it to build on `T: PartialOrd`,
which is slightly more verbose but much more standard and avoided the
problems.
Specifically, rename the `Const` struct as `ConstS` and re-introduce `Const` as
this:
```
pub struct Const<'tcx>(&'tcx Interned<ConstS>);
```
This now matches `Ty` and `Predicate` more closely, including using
pointer-based `eq` and `hash`.
Notable changes:
- `mk_const` now takes a `ConstS`.
- `Const` was copy, despite being 48 bytes. Now `ConstS` is not, so need a
we need separate arena for it, because we can't use the `Dropless` one any
more.
- Many `&'tcx Const<'tcx>`/`&Const<'tcx>` to `Const<'tcx>` changes
- Many `ct.ty` to `ct.ty()` and `ct.val` to `ct.val()` changes.
- Lots of tedious sigil fiddling.
Specifically, change `Ty` from this:
```
pub type Ty<'tcx> = &'tcx TyS<'tcx>;
```
to this
```
pub struct Ty<'tcx>(Interned<'tcx, TyS<'tcx>>);
```
There are two benefits to this.
- It's now a first class type, so we can define methods on it. This
means we can move a lot of methods away from `TyS`, leaving `TyS` as a
barely-used type, which is appropriate given that it's not meant to
be used directly.
- The uniqueness requirement is now explicit, via the `Interned` type.
E.g. the pointer-based `Eq` and `Hash` comes from `Interned`, rather
than via `TyS`, which wasn't obvious at all.
Much of this commit is boring churn. The interesting changes are in
these files:
- compiler/rustc_middle/src/arena.rs
- compiler/rustc_middle/src/mir/visit.rs
- compiler/rustc_middle/src/ty/context.rs
- compiler/rustc_middle/src/ty/mod.rs
Specifically:
- Most mentions of `TyS` are removed. It's very much a dumb struct now;
`Ty` has all the smarts.
- `TyS` now has `crate` visibility instead of `pub`.
- `TyS::make_for_test` is removed in favour of the static `BOOL_TY`,
which just works better with the new structure.
- The `Eq`/`Ord`/`Hash` impls are removed from `TyS`. `Interned`s impls
of `Eq`/`Hash` now suffice. `Ord` is now partly on `Interned`
(pointer-based, for the `Equal` case) and partly on `TyS`
(contents-based, for the other cases).
- There are many tedious sigil adjustments, i.e. adding or removing `*`
or `&`. They seem to be unavoidable.
by using an opaque type obligation to bubble up comparisons between opaque types and other types
Also uses proper obligation causes so that the body id works, because out of some reason nll uses body ids for logic instead of just diagnostics.
Create `core::fmt::ArgumentV1` with generics instead of fn pointer
Split from (and prerequisite of) #90488, as this seems to have perf implication.
`@rustbot` label: +T-libs
Replace `NestedVisitorMap` with generic `NestedFilter`
This is an attempt to make the `intravisit::Visitor` API simpler and "more const" with regard to nested visiting.
With this change, `intravisit::Visitor` does not visit nested things by default, unless you specify `type NestedFilter = nested_filter::OnlyBodies` (or `All`). `nested_visit_map` returns `Self::Map` instead of `NestedVisitorMap<Self::Map>`. It panics by default (unreachable if `type NestedFilter` is omitted).
One somewhat trixty thing here is that `nested_filter::{OnlyBodies, All}` live in `rustc_middle` so that they may have `type Map = map::Map` and so that `impl Visitor`s never need to specify `type Map` - it has a default of `Self::NestedFilter::Map`.
Remove deprecated LLVM-style inline assembly
The `llvm_asm!` was deprecated back in #87590 1.56.0, with intention to remove
it once `asm!` was stabilized, which already happened in #91728 1.59.0. Now it
is time to remove `llvm_asm!` to avoid continued maintenance cost.
Closes#70173.
Closes#92794.
Closes#87612.
Closes#82065.
cc `@rust-lang/wg-inline-asm`
r? `@Amanieu`
Closure capture cleanup & refactor
Follow up of #89648
Each commit is self-contained and the rationale/changes are documented in the commit message, so it's advisable to review commit by commit.
The code is significantly cleaner (at least IMO), but that could have some perf implication, so I'd suggest a perf run.
r? `@wesleywiser`
cc `@arora-aman`
Region info is completely unnecessary for upvar capture kind computation
and is only needed to create the final upvar tuple ty. Doing so makes
creation of UpvarCapture very cheap and expose further cleanup opportunity.
Remove `NullOp::Box`
Follow up of #89030 and MCP rust-lang/compiler-team#460.
~1 month later nothing seems to be broken, apart from a small regression that #89332 (1aac85bb716c09304b313d69d30d74fe7e8e1a8e) shows could be regained by remvoing the diverging path, so it shall be safe to continue and remove `NullOp::Box` completely.
r? `@jonas-schievink`
`@rustbot` label T-compiler
Remove `SymbolStr`
This was originally proposed in https://github.com/rust-lang/rust/pull/74554#discussion_r466203544. As well as removing the icky `SymbolStr` type, it allows the removal of a lot of `&` and `*` occurrences.
Best reviewed one commit at a time.
r? `@oli-obk`
Implement let-else type annotations natively
Tracking issue: #87335Fixes#89688, fixes#89807, edit: fixes #89960 as well
As explained in https://github.com/rust-lang/rust/issues/89688#issuecomment-940405082, the previous desugaring moved the let-else scrutinee into a dummy variable, which meant if you wanted to refer to it again in the else block, it had moved.
This introduces a new hir type, ~~`hir::LetExpr`~~ `hir::Let`, which takes over all the fields of `hir::ExprKind::Let(...)` and adds an optional type annotation. The `hir::Let` is then treated like a `hir::Local` when type checking a function body, specifically:
* `GatherLocalsVisitor` overrides a new `Visitor::visit_let_expr` and does pretty much exactly what it does for `visit_local`, assigning a local type to the `hir::Let` ~~(they could be deduplicated but they are right next to each other, so at least we know they're the same)~~
* It reuses the code in `check_decl_local` to typecheck the `hir::Let`, simply returning 'bool' for the expression type after doing that.
* ~~`FnCtxt::check_expr_let` passes this local type in to `demand_scrutinee_type`, and then imitates check_decl_local's pattern checking~~
* ~~`demand_scrutinee_type` (the blindest change for me, please give this extra scrutiny) uses this local type instead of of creating a new one~~
* ~~Just realised the `check_expr_with_needs` was passing NoExpectation further down, need to pass the type there too. And apparently this Expectation API already exists.~~
Some other misc notes:
* ~~Is the clippy code supposed to be autoformatted? I tried not to give huge diffs but maybe some rustfmt changes simply haven't hit it yet.~~
* in `rustc_ast_lowering/src/block.rs`, I noticed some existing `self.alias_attrs()` calls in `LoweringContext::lower_stmts` seem to be copying attributes from the lowered locals/etc to the statements. Is that right? I'm new at this, I don't know.
By changing `as_str()` to take `&self` instead of `self`, we can just
return `&str`. We're still lying about lifetimes, but it's a smaller lie
than before, where `SymbolStr` contained a (fake) `&'static str`!
Stabilize `iter::zip`
Hello all!
As the tracking issue (#83574) for `iter::zip` completed the final commenting period without any concerns being raised, I hereby submit this stabilization PR on the issue.
As the pull request that introduced the feature (#82917) states, the `iter::zip` function is a shorter way to zip two iterators. As it's generally a quality-of-life/ergonomic improvement, it has been integrated into the codebase without any trouble, and has been
used in many places across the rust compiler and standard library since March without any issues.
For more details, I would refer to `@cuviper's` original PR, or the [function's documentation](https://doc.rust-lang.org/std/iter/fn.zip.html).
fix clippy format using `cargo fmt -p clippy_{lints,utils}`
manually revert rustfmt line truncations
rename to hir::Let in clippy
Undo the shadowing of various `expr` variables after renaming `scrutinee`
reduce destructuring of hir::Let to avoid `expr` collisions
cargo fmt -p clippy_{lints,utils}
bless new clippy::author output
Don't destructure args tuple in format_args!
This allows Clippy to parse the HIR more simply since `arg0` is changed to `_args.0`. (cc rust-lang/rust-clippy#7843). From rustc's perspective, I think this is something between a lateral move and a tiny improvement since there are fewer bindings.
r? `@m-ou-se`
TraitKind -> Trait
TyAliasKind -> TyAlias
ImplKind -> Impl
FnKind -> Fn
All `*Kind`s in AST are supposed to be enums.
Tuple structs are converted to braced structs for the types above, and fields are reordered in syntactic order.
Also, mutable AST visitor now correctly visit spans in defaultness, unsafety, impl polarity and constness.
Coerce const FnDefs to implement const Fn traits
You can now pass a FnDef to a function expecting `F` where `F: ~const FnTrait`.
r? ``@oli-obk``
``@rustbot`` label T-compiler F-const_trait_impl
Introduce `Rvalue::ShallowInitBox`
Polished version of #88700.
Implements MCP rust-lang/compiler-team#460, and should allow #43596 to go forward.
In short, creating an empty box is split from a nullary-op `NullOp::Box` into two steps, first a call to `exchange_malloc`, then a `Rvalue::ShallowInitBox` which transmutes `*mut u8` to a shallow-initialized `Box<T>`. This allows the `exchange_malloc` call to unwind. Details can be found in the MCP.
`NullOp::Box` is not yet removed, purely to make reverting easier in case anything goes wrong as the result of this PR. If revert is needed a reversion of "Use Rvalue::ShallowInitBox for box expression" commit followed by a test bless should be sufficient.
Experiments in #88700 showed a very slight compile-time perf regression due to (supposedly) slightly more time spent in LLVM. We could omit unwind edge generation (in non-`oom=panic` case) in box expression MIR construction to restore perf; but I don't think it's necessary since runtime perf isn't affected and perf difference is rather small.
This allows the format_args! macro to keep the pre-expansion code out of
the unsafe block without doing gymnastics with nested `match`
expressions. This reduces codegen.
Introduce NullOp::AlignOf
This PR introduces `Rvalue::NullaryOp(NullOp::AlignOf, ty)`, which will be lowered from `align_of`, similar to `size_of` lowering to `Rvalue::NullaryOp(NullOp::SizeOf, ty)`.
The changes are originally part of #88700 but since it's not dependent on other changes and could have performance impact on its own, it's separated into its own PR.
Get piece unchecked in `write`
We already use specialized `zip`, but it seems like we can do a little better by not checking `pieces` length at all.
`Arguments` constructors are now unsafe. So the `format_args!` expansion now includes an `unsafe` block.
<details>
<summary>Local Bench Diff</summary>
```text
name before ns/iter after ns/iter diff ns/iter diff % speedup
fmt::write_str_macro1 22,967 19,718 -3,249 -14.15% x 1.16
fmt::write_str_macro2 35,527 32,654 -2,873 -8.09% x 1.09
fmt::write_str_macro_debug 571,953 575,973 4,020 0.70% x 0.99
fmt::write_str_ref 9,579 9,459 -120 -1.25% x 1.01
fmt::write_str_value 9,573 9,572 -1 -0.01% x 1.00
fmt::write_u128_max 176 173 -3 -1.70% x 1.02
fmt::write_u128_min 138 134 -4 -2.90% x 1.03
fmt::write_u64_max 139 136 -3 -2.16% x 1.02
fmt::write_u64_min 129 135 6 4.65% x 0.96
fmt::write_vec_macro1 24,401 22,273 -2,128 -8.72% x 1.10
fmt::write_vec_macro2 37,096 35,602 -1,494 -4.03% x 1.04
fmt::write_vec_macro_debug 588,291 589,575 1,284 0.22% x 1.00
fmt::write_vec_ref 9,568 9,732 164 1.71% x 0.98
fmt::write_vec_value 9,516 9,625 109 1.15% x 0.99
```
</details>
Fix clippy::collapsible_match with let expressions
This fixes rust-lang/rust-clippy#7575 which is a regression from #80357. I am fixing the bug here instead of in the clippy repo (if that's okay) because a) the regression has not been synced yet and b) I would like to land the fix on nightly asap.
The fix is basically to re-generalize `match` and `if let` for the lint implementation (they were split because `if let` no longer desugars to `match` in the HIR).
Also fixesrust-lang/rust-clippy#7586 and fixesrust-lang/rust-clippy#7591
cc `@rust-lang/clippy`
`@xFrednet` do you want to review this?
Since RFC 3052 soft deprecated the authors field anyway, hiding it from
crates.io, docs.rs, and making Cargo not add it by default, and it is
not generally up to date/useful information, we should remove it from
crates in this repo.
Remove refs from Pat slices
Changes `PatKind::Or(&'hir [&'hir Pat<'hir>])` to `PatKind::Or(&'hir [Pat<'hir>])` and others. This is more consistent with `ExprKind`, saves a little memory, and is a little easier to use.
This PR implements span quoting, allowing proc-macros to produce spans
pointing *into their own crate*. This is used by the unstable
`proc_macro::quote!` macro, allowing us to get error messages like this:
```
error[E0412]: cannot find type `MissingType` in this scope
--> $DIR/auxiliary/span-from-proc-macro.rs:37:20
|
LL | pub fn error_from_attribute(_args: TokenStream, _input: TokenStream) -> TokenStream {
| ----------------------------------------------------------------------------------- in this expansion of procedural macro `#[error_from_attribute]`
...
LL | field: MissingType
| ^^^^^^^^^^^ not found in this scope
|
::: $DIR/span-from-proc-macro.rs:8:1
|
LL | #[error_from_attribute]
| ----------------------- in this macro invocation
```
Here, `MissingType` occurs inside the implementation of the proc-macro
`#[error_from_attribute]`. Previosuly, this would always result in a
span pointing at `#[error_from_attribute]`
This will make many proc-macro-related error message much more useful -
when a proc-macro generates code containing an error, users will get an
error message pointing directly at that code (within the macro
definition), instead of always getting a span pointing at the macro
invocation site.
This is implemented as follows:
* When a proc-macro crate is being *compiled*, it causes the `quote!`
macro to get run. This saves all of the sapns in the input to `quote!`
into the metadata of *the proc-macro-crate* (which we are currently
compiling). The `quote!` macro then expands to a call to
`proc_macro::Span::recover_proc_macro_span(id)`, where `id` is an
opaque identifier for the span in the crate metadata.
* When the same proc-macro crate is *run* (e.g. it is loaded from disk
and invoked by some consumer crate), the call to
`proc_macro::Span::recover_proc_macro_span` causes us to load the span
from the proc-macro crate's metadata. The proc-macro then produces a
`TokenStream` containing a `Span` pointing into the proc-macro crate
itself.
The recursive nature of 'quote!' can be difficult to understand at
first. The file `src/test/ui/proc-macro/quote-debug.stdout` shows
the output of the `quote!` macro, which should make this eaier to
understand.
This PR also supports custom quoting spans in custom quote macros (e.g.
the `quote` crate). All span quoting goes through the
`proc_macro::quote_span` method, which can be called by a custom quote
macro to perform span quoting. An example of this usage is provided in
`src/test/ui/proc-macro/auxiliary/custom-quote.rs`
Custom quoting currently has a few limitations:
In order to quote a span, we need to generate a call to
`proc_macro::Span::recover_proc_macro_span`. However, proc-macros
support renaming the `proc_macro` crate, so we can't simply hardcode
this path. Previously, the `quote_span` method used the path
`crate::Span` - however, this only works when it is called by the
builtin `quote!` macro in the same crate. To support being called from
arbitrary crates, we need access to the name of the `proc_macro` crate
to generate a path. This PR adds an additional argument to `quote_span`
to specify the name of the `proc_macro` crate. Howver, this feels kind
of hacky, and we may want to change this before stabilizing anything
quote-related.
Additionally, using `quote_span` currently requires enabling the
`proc_macro_internals` feature. The builtin `quote!` macro
has an `#[allow_internal_unstable]` attribute, but this won't work for
custom quote implementations. This will likely require some additional
tricks to apply `allow_internal_unstable` to the span of
`proc_macro::Span::recover_proc_macro_span`.
