Add offset_of! macro (RFC 3308)
Implements https://github.com/rust-lang/rfcs/pull/3308 (tracking issue #106655) by adding the built in macro `core::mem::offset_of`. Two of the future possibilities are also implemented:
* Nested field accesses (without array indexing)
* DST support (for `Sized` fields)
I wrote this a few months ago, before the RFC merged. Now that it's merged, I decided to rebase and finish it.
cc `@thomcc` (RFC author)
Add `rustc_fluent_macro` to decouple fluent from `rustc_macros`
Fluent, with all the icu4x it brings in, takes quite some time to compile. `fluent_messages!` is only needed in further downstream rustc crates, but is blocking more upstream crates like `rustc_index`. By splitting it out, we allow `rustc_macros` to be compiled earlier, which speeds up `x check compiler` by about 5 seconds (and even more after the needless dependency on `serde_json` is removed from `rustc_data_structures`).
Fluent, with all the icu4x it brings in, takes quite some time to
compile. `fluent_messages!` is only needed in further downstream rustc
crates, but is blocking more upstream crates like `rustc_index`. By
splitting it out, we allow `rustc_macros` to be compiled earlier, which
speeds up `x check compiler` by about 5 seconds (and even more after the
needless dependency on `serde_json` is removed from
`rustc_data_structures`).
Preserve argument indexes when inlining MIR
We store argument indexes on VarDebugInfo. Unlike the previous method of relying on the variable index to know whether a variable is an argument, this survives MIR inlining.
We also no longer check if var.source_info.scope is the outermost scope. When a function gets inlined, the arguments to the inner function will no longer be in the outermost scope. What we care about though is whether they were in the outermost scope prior to inlining, which we know by whether we assigned an argument index.
Fixes#83217
I considered using `Option<NonZeroU16>` instead of `Option<u16>` to store the index. I didn't because `TypeFoldable` isn't implemented for `NonZeroU16` and because it looks like due to padding, it currently wouldn't make any difference. But I indexed from 1 anyway because (a) it'll make it easier if later it becomes worthwhile to use a `NonZeroU16` and because the arguments were previously indexed from 1, so it made for a smaller change.
This is my first PR on rust-lang/rust, so apologies if I've gotten anything not quite right.
Rollup of 8 pull requests
Successful merges:
- #110153 (Fix typos in compiler)
- #110165 (rustdoc: use CSS `overscroll-behavior` instead of JavaScript)
- #110175 (Symbol cleanups)
- #110203 (Remove `..` from return type notation)
- #110205 (rustdoc: make settings radio and checks thicker, less contrast)
- #110222 (Improve the error message when forwarding a matched fragment to another macro)
- #110237 (Split out a separate feature gate for impl trait in associated types)
- #110241 (tidy: Issue an error when UI test limits are too high)
Failed merges:
- #110218 (Remove `ToRegionVid`)
r? `@ghost`
`@rustbot` modify labels: rollup
We store argument indexes on VarDebugInfo. Unlike the previous method of
relying on the variable index to know whether a variable is an argument,
this survives MIR inlining.
We also no longer check if var.source_info.scope is the outermost scope.
When a function gets inlined, the arguments to the inner function will
no longer be in the outermost scope. What we care about though is
whether they were in the outermost scope prior to inlining, which we
know by whether we assigned an argument index.
Refactor unwind in MIR
This makes unwinding from current `Option<BasicBlock>` into
```rust
enum UnwindAction {
Continue,
Cleanup(BasicBlock),
Unreachable,
Terminate,
}
```
cc `@JakobDegen` `@RalfJung` `@Amanieu`
Check pattern refutability on THIR
The current `check_match` query is based on HIR, but partially re-lowers HIR into THIR.
This PR proposed to use the results of the `thir_body` query to check matches, instead of re-building THIR.
Most of the diagnostic changes are spans getting shorter, or commas/semicolons not getting removed.
This PR degrades the diagnostic for confusing constants in patterns (`let A = foo()` where `A` resolves to a `const A` somewhere): it does not point ot the definition of `const A` any more.
Unify terminology used in unwind action and terminator, and reflect
the fact that a nounwind panic is triggered instead of an immediate
abort is triggered for this terminator.
Fix `non_exhaustive_omitted_patterns` lint span
Fixes#109837
`DUMMY_SP` was being passed as the span in many cases where we have a span available to use. This meant that the location of the violating pattern wasn't shown, or the list of un-covered variants
r? `@Nilstrieb`
Update `ty::VariantDef` to use `IndexVec<FieldIdx, FieldDef>`
And while doing the updates for that, also uses `FieldIdx` in `ProjectionKind::Field` and `TypeckResults::field_indices`.
There's more places that could use it (like `rustc_const_eval` and `LayoutS`), but I tried to keep this PR from exploding to *even more* places.
Part 2/? of https://github.com/rust-lang/compiler-team/issues/606
And while doing the updates for that, also uses `FieldIdx` in `ProjectionKind::Field` and `TypeckResults::field_indices`.
There's more places that could use it (like `rustc_const_eval` and `LayoutS`), but I tried to keep this PR from exploding to *even more* places.
Part 2/? of https://github.com/rust-lang/compiler-team/issues/606
Partial stabilization of `once_cell`
This PR aims to stabilize a portion of the `once_cell` feature:
- `core::cell::OnceCell`
- `std::cell::OnceCell` (re-export of the above)
- `std::sync::OnceLock`
This will leave `LazyCell` and `LazyLock` unstabilized, which have been moved to the `lazy_cell` feature flag.
Tracking issue: https://github.com/rust-lang/rust/issues/74465 (does not fully close, but it may make sense to move to a new issue)
Future steps for separate PRs:
- ~~Add `#[inline]` to many methods~~ #105651
- Update cranelift usage of the `once_cell` crate
- Update rust-analyzer usage of the `once_cell` crate
- Update error messages discussing once_cell
## To be stabilized API summary
```rust
// core::cell (in core/cell/once.rs)
pub struct OnceCell<T> { .. }
impl<T> OnceCell<T> {
pub const fn new() -> OnceCell<T>;
pub fn get(&self) -> Option<&T>;
pub fn get_mut(&mut self) -> Option<&mut T>;
pub fn set(&self, value: T) -> Result<(), T>;
pub fn get_or_init<F>(&self, f: F) -> &T where F: FnOnce() -> T;
pub fn into_inner(self) -> Option<T>;
pub fn take(&mut self) -> Option<T>;
}
impl<T: Clone> Clone for OnceCell<T>;
impl<T: Debug> Debug for OnceCell<T>
impl<T> Default for OnceCell<T>;
impl<T> From<T> for OnceCell<T>;
impl<T: PartialEq> PartialEq for OnceCell<T>;
impl<T: Eq> Eq for OnceCell<T>;
```
```rust
// std::sync (in std/sync/once_lock.rs)
impl<T> OnceLock<T> {
pub const fn new() -> OnceLock<T>;
pub fn get(&self) -> Option<&T>;
pub fn get_mut(&mut self) -> Option<&mut T>;
pub fn set(&self, value: T) -> Result<(), T>;
pub fn get_or_init<F>(&self, f: F) -> &T where F: FnOnce() -> T;
pub fn into_inner(self) -> Option<T>;
pub fn take(&mut self) -> Option<T>;
}
impl<T: Clone> Clone for OnceLock<T>;
impl<T: Debug> Debug for OnceLock<T>;
impl<T> Default for OnceLock<T>;
impl<#[may_dangle] T> Drop for OnceLock<T>;
impl<T> From<T> for OnceLock<T>;
impl<T: PartialEq> PartialEq for OnceLock<T>
impl<T: Eq> Eq for OnceLock<T>;
impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceLock<T>;
unsafe impl<T: Send> Send for OnceLock<T>;
unsafe impl<T: Sync + Send> Sync for OnceLock<T>;
impl<T: UnwindSafe> UnwindSafe for OnceLock<T>;
```
No longer planned as part of this PR, and moved to the `rust_cell_try` feature gate:
```rust
impl<T> OnceCell<T> {
pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E> where F: FnOnce() -> Result<T, E>;
}
impl<T> OnceLock<T> {
pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E> where F: FnOnce() -> Result<T, E>;
}
```
I am new to this process so would appreciate mentorship wherever needed.
The first PR for https://github.com/rust-lang/compiler-team/issues/606
This is just the move-and-rename, because it's plenty big-and-bitrotty already. Future PRs will start using `FieldIdx` more broadly, and concomitantly removing `FieldIdx::new`s.
Clarify the 'use a constant in a pattern' error message
```rs
use std::borrow::Cow;
const ERROR_CODE: Cow<'_, str> = Cow::Borrowed("23505");
fn main() {
let x = Cow::from("23505");
match x {
ERROR_CODE => {}
}
}
```
```
error: to use a constant of type `Cow` in a pattern, `Cow` must be annotated with `#[derive(PartialEq, Eq)]`
--> src/main.rs:9:9
|
9 | ERROR_CODE => {}
| ^^^^^^^^^^
error: could not compile `playground` due to previous error
```
It seems helpful to link to StructuralEq in this message. I was a little confused, because `Cow<'_, str>` implements PartialEq and Eq, but they're not derived, which I learned is necessary for structural equality and using constants in patterns (thanks to the Rust community Discord server)
For tests, should I update every occurrence of this message? I see tests where this is still a warning and I'm not sure if I should update those.
Since structs are always `VariantIdx(0)`, there's a bunch of files where the only reason they had `VariantIdx` or `vec::Idx` imported at all was to get the first variant.
So this uses a constant for that, and adds some doc-comments to `VariantIdx` while I'm there, since it doesn't have any today.
Rollup of 7 pull requests
Successful merges:
- #108541 (Suppress `opaque_hidden_inferred_bound` for nested RPITs)
- #109137 (resolve: Querify most cstore access methods (subset 2))
- #109380 (add `known-bug` test for unsoundness issue)
- #109462 (Make alias-eq have a relation direction (and rename it to alias-relate))
- #109475 (Simpler checked shifts in MIR building)
- #109504 (Stabilize `arc_into_inner` and `rc_into_inner`.)
- #109506 (make param bound vars visibly bound vars with -Zverbose)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Simpler checked shifts in MIR building
Doing masking to check unsigned shift amounts is overcomplicated; just comparing the shift directly saves a statement and a temporary, as well as is much easier to read as a human. And shifting by unsigned is the canonical case -- notably, all the library shifting methods (that don't support every type) take shift RHSs as `u32` -- so we might as well make that simpler since it's easy to do so.
This PR also changes *signed* shift amounts to `IntToInt` casts and then uses the same check as for unsigned. The bit-masking is a nice trick, but for example LLVM actually canonicalizes it to an unsigned comparison anyway <https://rust.godbolt.org/z/8h59fMGT4> so I don't think it's worth the effort and the extra `Constant`. (If MIR's `assert` was `assert_nz` then the masking might make sense, but when the `!=` uses another statement I think the comparison is better.)
To review, I suggest looking at 2ee0468c49 first -- that's the interesting code change and has a MIR diff.
My favourite part of the diff:
```diff
- _20 = BitAnd(_19, const 340282366920938463463374607431768211448_u128); // scope 0 at $DIR/shifts.rs:+2:34: +2:44
- _21 = Ne(move _20, const 0_u128); // scope 0 at $DIR/shifts.rs:+2:34: +2:44
- assert(!move _21, "attempt to shift right by `{}`, which would overflow", _19) -> [success: bb3, unwind: bb7]; // scope 0 at $DIR/shifts.rs:+2:34: +2:44
+ _18 = Lt(_17, const 8_u128); // scope 0 at $DIR/shifts.rs:+2:34: +2:44
+ assert(move _18, "attempt to shift right by `{}`, which would overflow", _17) -> [success: bb3, unwind: bb7]; // scope 0 at $DIR/shifts.rs:+2:34: +2:44
```
Updates `interpret`, `codegen_ssa`, and `codegen_cranelift` to consume the new cast instead of the intrinsic.
Includes `CastTransmute` for custom MIR building, to be able to test the extra UB.
a general type system cleanup
removes the helper functions `traits::fully_solve_X` as they add more complexity then they are worth. It's confusing which of these helpers should be used in which context.
changes the way we deal with overflow to always add depth in `evaluate_predicates_recursively`. It may make sense to actually fully transition to not have `recursion_depth` on obligations but that's probably a bit too much for this PR.
also removes some other small - and imo unnecessary - helpers.
r? types
Remove box expressions from HIR
After #108516, `#[rustc_box]` is used at HIR->THIR lowering and this is no longer emitted, so it can be removed.
This is based on top of #108471 to help with conflicts, so 43490488ccacd1a822e9c621f5ed6fca99959a0b is the only relevant commit (sorry for all the duplicated pings!)
````@rustbot```` label +S-blocked
Wrap the whole LocalInfo in ClearCrossCrate.
MIR contains a lot of information about locals. The primary purpose of this information is the quality of borrowck diagnostics.
This PR aims to drop this information after MIR analyses are finished, ie. starting from post-cleanup runtime MIR.
Implement checked Shl/Shr at MIR building.
This does not require any special handling by codegen backends,
as the overflow behaviour is entirely determined by the rhs (shift amount).
This allows MIR ConstProp to remove the overflow check for constant shifts.
~There is an existing different behaviour between cg_llvm and cg_clif (cc `@bjorn3).`
I took cg_llvm's one as reference: overflow if `rhs < 0 || rhs > number_of_bits_in_lhs_ty`.~
EDIT: `cg_llvm` and `cg_clif` implement the overflow check differently. This PR uses `cg_llvm`'s implementation based on a `BitAnd` instead of `cg_clif`'s one based on an unsigned comparison.
Ensure value is on the on-disk cache before returning from `ensure()`.
The current logic for `ensure()` a query just checks that the node is green in the dependency graph.
However, a lot of places use `ensure()` to prevent the query from being called later. This is the case before stealing a query result.
If the query is actually green but the value is not available in the on-disk cache, `ensure` would return, but a subsequent call to the full query would run the code, and attempt to read from a stolen value.
This PR conforms the query system to the usage by checking whether the queried value is loadable from disk before returning.
Sadly, I can't manage to craft a proper test...
Should fix all instances of "attempted to read from stolen value".
tidy: enforce comment blocks to have an even number of backticks
After PR #108694, most unmatched backticks in `compiler/` comments have been eliminated. This PR adds a tidy lint to ensure no new unmatched backticks are added, and either addresses the lint in the remaining instances it found, or allows it.
Very often, backtick containing sections wrap around lines, for example:
```Rust
// This function takes a tuple `(Vec<String>,
// Box<[u8]>)` and transforms it into `Vec<u8>`.
```
The lint is implemented to work on top of blocks, counting each line with a `//` into a block, and counting if there are an odd or even number of backticks in the entire block, instead of looking at just a single line.
This makes it easier to open the messages file while developing on features.
The commit was the result of automatted changes:
for p in compiler/rustc_*; do mv $p/locales/en-US.ftl $p/messages.ftl; rmdir $p/locales; done
for p in compiler/rustc_*; do sed -i "s#\.\./locales/en-US.ftl#../messages.ftl#" $p/src/lib.rs; done
rustc_middle: Remove trait `DefIdTree`
This trait was a way to generalize over both `TyCtxt` and `Resolver`, but now `Resolver` has access to `TyCtxt`, so this trait is no longer necessary.
Desugaring of drop and replace at MIR build
This commit desugars the drop and replace deriving from an
assignment at MIR build, avoiding the construction of the
`DropAndReplace` terminator (which will be removed in a following PR).
In order to retain the same error messages for replaces a new
`DesugaringKind::Replace` variant is introduced.
The changes in the borrowck are also useful for future work in moving drop elaboration
before borrowck, as no `DropAndReplace` would be present there anymore.
Notes on test diffs:
* `tests/ui/borrowck/issue-58776-borrowck-scans-children`: the assignment deriving from the desugaring kills the borrow.
* `tests/ui/async-await/async-fn-size-uninit-locals.rs`, `tests/mir-opt/issue_41110.test.ElaborateDrops.after.mir`, `tests/mir-opt/issue_41888.main.ElaborateDrops.after.mir`: drop elaboration generates (or reads from) a useless drop flag due to an issue with the dataflow analysis. Will be fixed independently by https://github.com/rust-lang/rust/pull/106430.
See https://github.com/rust-lang/rust/pull/104488 for more context
Don't call `temporary_scope` twice.
`mirror_expr_inner` calls `temporary_scope`. It then calls `make_mirror_unadjusted` which makes an identical call to `temporary_scope`.
This commit changes the `mirror_expr_inner` to get the `temp_lifetime` out of the expression produced by `make_mirror_unadjusted`, similar to how it currently gets the type.
r? `@cjgillot`
This commit desugars the drop and replace deriving from an
assignment at MIR build, avoiding the construction of the
DropAndReplace terminator (which will be removed in a followign PR)
In order to retain the same error messages for replaces a new
DesugaringKind::Replace variant is introduced.
`mirror_expr_inner` calls `temporary_scope`. It then calls
`make_mirror_unadjusted` which makes an identical call to
`temporary_scope`.
This commit changes the `mirror_expr_inner` to get the `temp_lifetime`
out of the expression produced by `make_mirror_unadjusted`, similar to
how it currently gets the type.
Restrict `#[rustc_box]` to `Box::new` calls
Currently, `#[rustc_box]` can be applied to any call expression with a single argument. This PR only allows it to be applied to calls to `Box::new`
Avoid invoking typeck from borrowck
This PR attempts to reduce direct dependencies between typeck and MIR-related queries. The goal is to have all the information transit either through THIR or through dedicated queries that avoid depending on the whole `TypeckResults`.
In a first commit, we store the type information that MIR building requires into THIR. This avoids edges between mir_built and typeck.
In the second and third commit, we wrap informations around closures (upvars, kind origin and user-provided signature) to avoid borrowck depending on typeck information.
There should be a single remaining borrowck -> typeck edge in the good path, due to inline consts.
Move THIR printing to rustc_mir_build.
https://github.com/rust-lang/rust/pull/107451 increased the compilation time of `rustc_middle` by 10% = 3s.
As https://github.com/rust-lang/rust/pull/107006 adds quite a lot of code to rustc_middle, I suspect it to be the cause.
This PR moves the THIR printing code to `rustc_mir_build`, where the query provider lives, in order to benefit from higher parallelism when compiling rustc.
(This is a large commit. The changes to
`compiler/rustc_middle/src/ty/context.rs` are the most important ones.)
The current naming scheme is a mess, with a mix of `_intern_`, `intern_`
and `mk_` prefixes, with little consistency. In particular, in many
cases it's easy to use an iterator interner when a (preferable) slice
interner is available.
The guiding principles of the new naming system:
- No `_intern_` prefixes.
- The `intern_` prefix is for internal operations.
- The `mk_` prefix is for external operations.
- For cases where there is a slice interner and an iterator interner,
the former is `mk_foo` and the latter is `mk_foo_from_iter`.
Also, `slice_interners!` and `direct_interners!` can now be `pub` or
non-`pub`, which helps enforce the internal/external operations
division.
It's not perfect, but I think it's a clear improvement.
The following lists show everything that was renamed.
slice_interners
- const_list
- mk_const_list -> mk_const_list_from_iter
- intern_const_list -> mk_const_list
- substs
- mk_substs -> mk_substs_from_iter
- intern_substs -> mk_substs
- check_substs -> check_and_mk_substs (this is a weird one)
- canonical_var_infos
- intern_canonical_var_infos -> mk_canonical_var_infos
- poly_existential_predicates
- mk_poly_existential_predicates -> mk_poly_existential_predicates_from_iter
- intern_poly_existential_predicates -> mk_poly_existential_predicates
- _intern_poly_existential_predicates -> intern_poly_existential_predicates
- predicates
- mk_predicates -> mk_predicates_from_iter
- intern_predicates -> mk_predicates
- _intern_predicates -> intern_predicates
- projs
- intern_projs -> mk_projs
- place_elems
- mk_place_elems -> mk_place_elems_from_iter
- intern_place_elems -> mk_place_elems
- bound_variable_kinds
- mk_bound_variable_kinds -> mk_bound_variable_kinds_from_iter
- intern_bound_variable_kinds -> mk_bound_variable_kinds
direct_interners
- region
- intern_region (unchanged)
- const
- mk_const_internal -> intern_const
- const_allocation
- intern_const_alloc -> mk_const_alloc
- layout
- intern_layout -> mk_layout
- adt_def
- intern_adt_def -> mk_adt_def_from_data (unusual case, hard to avoid)
- alloc_adt_def(!) -> mk_adt_def
- external_constraints
- intern_external_constraints -> mk_external_constraints
Other
- type_list
- mk_type_list -> mk_type_list_from_iter
- intern_type_list -> mk_type_list
- tup
- mk_tup -> mk_tup_from_iter
- intern_tup -> mk_tup
Use `tcx.ty_error_with_guaranteed` in more places, rename variants
1. Use `ty_error_with_guaranteed` more so we don't delay so many span bugs
2. Rename `ty_error_with_guaranteed` to `ty_error`, `ty_error` to `ty_error_misc`. This is to incentivize using the former over the latter in cases where we already are witness to a `ErrorGuaranteed` token.
Second commit is just name replacement, so the first commit can be reviewed on its own with more scrutiny.
Use associated type bounds in some places in the compiler
Use associated type bounds for some nested `impl Trait<Assoc = impl Trait2>` cases. I'm generally keen to introduce new lang features that are more mature into the compiler, but maybe let's see what others think?
Side-note: I was surprised that the only use-cases of nested impl trait in the compiler are just iterator related?!
Remove type-traversal trait aliases
#107924 moved the type traversal (folding and visiting) traits into the type library, but created trait aliases in `rustc_middle` to minimise both the API churn for trait consumers and the arising boilerplate. As mentioned in that PR, an alternative approach of defining subtraits with blanket implementations of the respective supertraits was also considered at that time but was ruled out as not adding much value.
Unfortunately, it has since emerged that rust-analyzer has difficulty with these trait aliases at present, resulting in a degraded contributor experience (see the recent [r-a has become useless](https://rust-lang.zulipchat.com/#narrow/stream/182449-t-compiler.2Fhelp/topic/r-a.20has.20become.20useless) topic on the #t-compiler/help Zulip stream).
This PR removes the trait aliases, and accordingly the underlying type library traits are now used directly; they are parameterised by `TyCtxt<'tcx>` rather than just the `'tcx` lifetime, and imports have been updated to reflect the fact that the trait aliases' explicitly named traits are no longer automatically brought into scope. These changes also roll-back the (no-longer required) workarounds to #107747 that were made in b409329c62.
Since this PR is just a find+replace together with the changes necessary for compilation & tidy to pass, it's currently just one mega-commit. Let me know if you'd like it broken up.
r? `@oli-obk`
Instead of loading the Fluent resources for every crate in
`rustc_error_messages`, each crate generates typed identifiers for its
own diagnostics and creates a static which are pulled together in the
`rustc_driver` crate and provided to the diagnostic emitter.
Signed-off-by: David Wood <david.wood@huawei.com>
Rollup of 7 pull requests
Successful merges:
- #106347 (More accurate spans for arg removal suggestion)
- #108057 (Prevent some attributes from being merged with others on reexports)
- #108090 (`if $c:expr { Some($r:expr) } else { None }` =>> `$c.then(|| $r)`)
- #108092 (note issue for feature(packed_bundled_libs))
- #108099 (use chars instead of strings where applicable)
- #108115 (Do not ICE on unmet trait alias bounds)
- #108125 (Add new people to the compiletest review rotation)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Much like there are specialized variants of `mk_ty`. This will enable
some optimization in the next commit.
Also rename the existing `re_error*` functions as `mk_re_error*`, for
consistency.
Output tree representation on thir-tree
The current output of `-Zunpretty=thir-tree` is really cumbersome to work with, using an actual tree representation should make it easier to see what the thir looks like.
Rollup of 8 pull requests
Successful merges:
- #106904 (Preserve split DWARF files when building archives.)
- #106971 (Handle diagnostics customization on the fluent side (for one specific diagnostic))
- #106978 (Migrate mir_build's borrow conflicts)
- #107150 (`ty::tls` cleanups)
- #107168 (Use a type-alias-impl-trait in `ObligationForest`)
- #107189 (Encode info for Adt in a single place.)
- #107322 (Custom mir: Add support for some remaining, easy to support constructs)
- #107323 (Disable ConstGoto opt in cleanup blocks)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Custom mir: Add support for some remaining, easy to support constructs
Some documentation for previous changes and support for `Deinit`, checked binops, len, and array repetition
r? ```@oli-obk``` or ```@tmiasko```
Migrate mir_build's borrow conflicts
This also changes the error message slightly, for two reasons:
- I'm not a fan of saying "value borrowed, by `x`, here"
- it simplifies the error implementation significantly.
Move format_args!() into AST (and expand it during AST lowering)
Implements https://github.com/rust-lang/compiler-team/issues/541
This moves FormatArgs from rustc_builtin_macros to rustc_ast_lowering. For now, the end result is the same. But this allows for future changes to do smarter things with format_args!(). It also allows Clippy to directly access the ast::FormatArgs, making things a lot easier.
This change turns the format args types into lang items. The builtin macro used to refer to them by their path. After this change, the path is no longer relevant, making it easier to make changes in `core`.
This updates clippy to use the new language items, but this doesn't yet make clippy use the ast::FormatArgs structure that's now available. That should be done after this is merged.
Custom MIR: Support binary and unary operations
Lower binary and unary operations directly to corresponding unchecked MIR
operations. Ultimately this might not be syntax we want, but it allows for
experimentation in the meantime.
r? ````@oli-obk```` ````@JakobDegen````
use LocalDefId instead of HirId in trait resolution to simplify
the obligation clause resolution
Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Rollup of 8 pull requests
Successful merges:
- #106783 (Recover labels written as identifiers)
- #106973 (Don't treat closures from other crates as local)
- #106979 (Document how to get the type of a default associated type)
- #107053 (signal update string representation for haiku.)
- #107058 (Recognise double-equals homoglyph)
- #107067 (Custom MIR: Support storage statements)
- #107076 (Added const-generic ui test case for issue #106419)
- #107091 (Fix broken format strings in `infer.ftl`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
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 mir_build diagnostics 2 of 3
The first three commits are fairly boring, however I've made some changes to the output of the match checking diagnostics.
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.
Clarify that raw retags are not permitted in Mir
Not sure when this changed, but documentation and the validator needed to be updated. This also removes raw retags from custom mir.
cc rust-lang/miri#2735
r? `@RalfJung`
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.
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.
Migrate rustc_mir_build diagnostics
Rebases https://github.com/rust-lang/rust/pull/100854
~~The remaining issue is how to better resolve 72bea68af4~~
~~The diagnostic macros seems to generate a broken diagnostic, and I couldn't figure out how to manually format the fluent message, so I hardcoded the format string for now. I'd like pointers to a better fix for this.~~
Also, I'm not 100% sure I didn't mess up a rebase somewhere 🙂
r? `@davidtwco`
Support call and drop terminators in custom mir
The only caveat with this change is that cleanup blocks are not supported. I would like to add them, but it's not quite clear to me what the best way to do that is, so I'll have to think about it some more.
r? ``@oli-obk``
Custom MIR: Many more improvements
Commits are each atomic changes, best reviewed one at a time, with the exception that the last commit includes all the documentation.
### First commit
Unsafetyck was not correctly disabled before for `dialect = "built"` custom MIR. This is fixed and a regression test is added.
### Second commit
Implements `Discriminant`, `SetDiscriminant`, and `SwitchInt`.
### Third commit
Implements indexing, field, and variant projections.
### Fourth commit
Documents the previous commits and everything else.
There is some amount of weirdness here due to having to beat Rust syntax into cooperating with MIR concepts, but it hopefully should not be too much. All of it is documented.
r? `@oli-obk`
Combine `ty::Projection` and `ty::Opaque` into `ty::Alias`
Implements https://github.com/rust-lang/types-team/issues/79.
This PR consolidates `ty::Projection` and `ty::Opaque` into a single `ty::Alias`, with an `AliasKind` and `AliasTy` type (renamed from `ty::ProjectionTy`, which is the inner data of `ty::Projection`) defined as so:
```
enum AliasKind {
Projection,
Opaque,
}
struct AliasTy<'tcx> {
def_id: DefId,
substs: SubstsRef<'tcx>,
}
```
Since we don't have access to `TyCtxt` in type flags computation, and because repeatedly calling `DefKind` on the def-id is expensive, these two types are distinguished with `ty::AliasKind`, conveniently glob-imported into `ty::{Projection, Opaque}`. For example:
```diff
match ty.kind() {
- ty::Opaque(..) =>
+ ty::Alias(ty::Opaque, ..) => {}
_ => {}
}
```
This PR also consolidates match arms that treated `ty::Opaque` and `ty::Projection` identically.
r? `@ghost`
Change pattern borrowing suggestions to be verbose and remove invalid suggestion
Synthesize a more accurate span and use verbose suggestion output to
make the message clearer.
Do not suggest borrowing binding in pattern in let else. Fix#104838.
Allow unsafe through inline const
Handle similar to closures.
Address https://github.com/rust-lang/rust/pull/104087#issuecomment-1324173328
Note that this PR does not fix the issue for `unsafe { [0; function_requiring_unsafe()] }`. This is fundamentally unfixable for MIR unsafeck IMO.
This PR also does not fix unsafety checking for inline const in pattern position. It actually breaks it, allowing unsafe functions to be used in inline const in pattern position without unsafe blocks. Inline const in pattern position is not visible in MIR so ignored by MIR unsafety checking (currently it is also not checked by borrow checker, which is the reason why it's considered an incomplete feature).
`@rustbot` label: +T-lang +F-inline_const
Remove `token::Lit` from `ast::MetaItemLit`.
Currently `ast::MetaItemLit` represents the literal kind twice. This PR removes that redundancy. Best reviewed one commit at a time.
r? `@petrochenkov`
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 :/
This is required to distinguish between cooked and raw byte string
literals in an `ast::LitKind`, without referring to an adjacent
`token::Lit`. It's a prerequisite for the next commit.
`mk_const(ty::ConstKind::X(...), ty)` can now be simplified to
`mk_cosnt(..., ty)`.
I searched with the following regex: \mk_const\([\n\s]*(ty::)?ConstKind\
I've left `ty::ConstKind::{Bound, Error}` as-is, they seem clearer this
way.
Use `as_deref` in compiler (but only where it makes sense)
This simplifies some code :3
(there are some changes that are not exacly `as_deref`, but more like "clever `Option`/`Result` method use")
Only declare bindings for if-let guards once per arm
Currently, each candidate for a match arm uses separate locals for the bindings in the if-let guard, causing problems (#88015) when those branches converge in the arm body.
Fixes#88015 (🤞)
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.
Reduce span of let else irrefutable_let_patterns warning
Huge spans aren't good for IDE users as they underline constructs that are possibly multiline.
Similar PR to #90761 which did the same for the `unused_macros` lint.
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
Suppress irrefutable let patterns lint for prefixes in match guards
In match guards, irrefutable prefixes might use the bindings created by the match pattern. Ideally, we check for this, but we can do the next best thing and just not lint for irrefutable prefixes in match guards.
Fixes#98361
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.
In match guards, irrefutable prefixes might use the bindings created
by the match pattern. Ideally, we check for this, but we can do the
next best thing and just not lint for irrefutable prefixes in match
guards.
Remove `mir::CastKind::Misc`
As discussed in #97649 `mir::CastKind::Misc` is not clear, this PR addresses that by creating a new enum variant for every valid cast.
r? ````@oli-obk````
Fix unwind drop glue for if-then scopes
cc `@est31`
Fix#102317Fix#99852
This PR fixes the drop glue for unwinding from a panic originated in a drop while breaking out for the else block in an `if-then` scope.
MIR validation does not fail for the synchronous versions of the test program, because `StorageDead` statements are skipped over in the unwinding process. It is only becoming a problem when it is inside a generator where `StorageDead` must be kept around.
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 😢
`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.
Fix lint scoping for let-else.
The scoping for let-else is inconsistent with HIR nesting. This creates cases, in `ui/let-else/let-else-allow-unused.rs` for instance, where an `allow` lint attribute does not apply to the bindings created by `let-else`.
This PR is an attempt to correct this.
As there is no lint that currently relies on this, the test for this behaviour is https://github.com/rust-lang/rust/pull/101500.
cc `@dingxiangfei2009` as you filed https://github.com/rust-lang/rust/pull/101894
Avoid duplicating StorageLive in let-else
cc `@est31`
Fix#101867Fix#101932#101410 introduced directives to activate storages of bindings in let-else earlier. However, since it is using the machinery of `match` and friends for pattern matching and binding, those storages are activated for the second time. This PR adjusts this behavior and avoid the duplicated activation for let-else statements.
On later stages, the feature is already stable.
Result of running:
rg -l "feature.let_else" compiler/ src/librustdoc/ library/ | xargs sed -s -i "s#\\[feature.let_else#\\[cfg_attr\\(bootstrap, feature\\(let_else\\)#"
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`
Shrink span for bindings with subpatterns.
Bindings with nested patterns (`binding @ pat` syntax) currently point to the full pattern. This PR proposes to shrink the span to stop before the ````@`.``` This makes the diagnostics for move/mutability conflicts clearer, as they not point to the `binding` only, instead of the full pat.
r? ```@estebank```
`Builder::expr_into_pattern` has a single call site. Currently the
`pattern` argument at the call site is always cloned.
This commit changes things so that we instead do a clone within
`expr_into_pattern`, but only if the pattern has the
`PatKind::AscribeUserType` kind, and we only clone the annotation within
the pattern instead of the entire pattern.
`thir::Pat::kind` is a `Box<PatKind>`, which doesn't follow the usual
pattern in AST/HIR/THIR which is that the "kind" enum for a node is
stored inline within the parent struct.
This commit makes the `PatKind` directly inline within the `Pat`. This
requires using `Box<Pat>` in all the types that hold a `Pat.
Ideally, `Pat` would be stored in `Thir` like `Expr` and `Stmt` and
referred to with a `PatId` rather than `Box<Pat>`. But this is hard to
do because lots of `Pat`s get created after the destruction of the `Cx`
that does normal THIR building. But this does get us a step closer to
`PatId`, because all the `Box<Pat>` occurrences would be replaced with
`PatId` if `PatId` ever happened.
At 128 bytes, `Pat` is large. Subsequent commits will shrink it.
This PR will fix some typos detected by [typos].
I only picked the ones I was sure were spelling errors to fix, mostly in
the comments.
[typos]: https://github.com/crate-ci/typos
Replace `Body::basic_blocks()` with field access
Since the refactoring in #98930, it is possible to borrow the basic blocks
independently from other parts of MIR by accessing the `basic_blocks` field
directly.
Replace unnecessary `Body::basic_blocks()` method with a direct field access,
which has an additional benefit of borrowing the basic blocks only.
let-else: break out to one scope higher for let-else
```@est31``` This PR follows up with #99518 which is to break out to the last remainder scope. It breaks to the out-most `region_scope` of the block if the first statement is a `let-else`.
Expand potential inner `Or` pattern for THIR
Code assumed there wouldn't be a deeper `Or` pattern inside expanded `PatStack` this fixes it by looking for the `Or` pattern inside expanded `PatStack`.
A more ideal solution would be recursively doing this but I haven't found a good way to do that.
_fixes #97898_
never consider unsafe blocks unused if they would be required with deny(unsafe_op_in_unsafe_fn)
Judging from https://github.com/rust-lang/rust/issues/71668#issuecomment-1200317370 the consensus nowadays seems to be that we should never consider an unsafe block unused if it was required with `deny(unsafe_op_in_unsafe_fn)`, no matter whether that lint is actually enabled or not. So let's adjust rustc accordingly.
The first commit does the change, the 2nd does some cleanup.
Determine match_has_guard from candidates instead of looking up thir table again
Currently looking through mir build of matches because of interest in deref patterns. Finding some micro-optimizable things.
Enable unused_parens for match arms
Fixes: https://github.com/rust-lang/rust/issues/92751
Currently I can't get the `stderr` to work with `./x.py test`, but this should fix the issue. Help would be appreciated!
Some `is_useful` cleanups
#98582 was reverted because it was a perf regression.
https://github.com/rust-lang/rust/pull/99806 reintroduces the changes, but this PR picks individual ones that have no regressions.
Let-else: break out scopes when a let-else pattern fails to match
This PR will commit to a new behavior so that values from initializer expressions are dropped earlier when a let-else pattern fails to match.
Fix#98672.
Close#93951.
cc `@camsteffen` `@est31`
Deeply deny fn and raw ptrs in const generics
I think this is right -- just because we wrap a fn ptr in a wrapper type does not mean we should allow it in a const parameter.
We now reject both of these in the same way:
```
#![feature(adt_const_params)]
#[derive(Eq, PartialEq)]
struct Wrapper();
fn foo<const W: Wrapper>() {}
fn foo2<const F: fn()>() {}
```
This does regress one test (`src/test/ui/consts/refs_check_const_eq-issue-88384.stderr`), but I'm not sure it should've passed in the first place.
cc: ``@b-naber`` who introduced that test^
fixes#99641
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``
Implement `SourceMap::is_span_accessible`
This patch adds `SourceMap::is_span_accessible` and replaces `span_to_snippet(span).is_ok()` and `span_to_snippet(span).is_err()` with it. This removes a `&str` to `String` conversion.
There are several indications that we should not ZST as a ScalarInt:
- We had two ways to have ZST valtrees, either an empty `Branch` or a `Leaf` with a ZST in it.
`ValTree::zst()` used the former, but the latter could possibly arise as well.
- Likewise, the interpreter had `Immediate::Uninit` and `Immediate::Scalar(Scalar::ZST)`.
- LLVM codegen already had to special-case ZST ScalarInt.
So instead add new ZST variants to those types that did not have other variants
which could be used for this purpose.
This makes it possible to mutably borrow different fields of the MIR
body without resorting to methods like `basic_blocks_local_decls_mut_and_var_debug_info`.
To preserve validity of control flow graph caches in the presence of
modifications, a new struct `BasicBlocks` wraps together basic blocks
and control flow graph caches.
The `BasicBlocks` dereferences to `IndexVec<BasicBlock, BasicBlockData>`.
On the other hand a mutable access requires explicit `as_mut()` call.
lints: mostly translatable diagnostics
As lints are created slightly differently than other diagnostics, intended to try make them translatable first and then look into the applicability of diagnostic structs but ended up just making most of the diagnostics in the crate translatable (which will still be useful if I do make a lot of them structs later anyway).
r? ``@compiler-errors``
Change enum->int casts to not go through MIR casts.
follow-up to https://github.com/rust-lang/rust/pull/96814
this simplifies all backends and even gives LLVM more information about the return value of `Rvalue::Discriminant`, enabling optimizations in more cases.
Rewrite dead-code pass to avoid fetching HIR.
This allows to get a more uniform handling of spans, and to simplify the grouping of diagnostics for variants and fields.
Accept `DiagnosticMessage` in `LintDiagnosticBuilder::build` so that
lints can be built with translatable diagnostic messages.
Signed-off-by: David Wood <david.wood@huawei.com>
Avoid some `&str` to `String` conversions with `MultiSpan::push_span_label`
This patch removes some`&str` to `String` conversions with `MultiSpan::push_span_label`.
Don't omit comma when suggesting wildcard arm after macro expr
* Also adds `Span::eq_ctxt` to consolidate the various usages of `span.ctxt() == other.ctxt()`
* Also fixes an unhygenic usage of spans which caused the suggestion to render weirdly when we had one arm match in a macro
* Also always suggests a comma (i.e. even after a block) if we're rendering a wildcard arm in a single-line match (looks prettier 🌹)
Fixes#94866
Fix `SourceScope` for `if let` bindings.
Fixes#97799.
I'm not sure how to test this properly, is there any way to observe the difference in behavior apart from `ui` tests? I'm worried that they would be overlooked in the case of a regression.
This commit removes the `a == b` early return, which isn't useful in
practice, and replaces it with one that helps matches with many ranges,
including char ranges.
The code is clearer and simpler without it. Note that the `a == b` early
return at the top of the function means the `a == b` test at the end of
the function could never succeed.
It's never executed when running the entire test suite. I think it's
because of the early return at the top of the function if `a.ty() != ty`
succeeds.
This is a performance win for `unicode-normalization`.
The commit also removes the closure, which isn't necessary. And
reformulates the comparison into a form I find easier to read.
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.
Fix precise field capture of univariant enums
When constructing a MIR from a THIR field expression, introduce an
additional downcast projection before accessing a field of an enum.
When rebasing a place builder on top of a captured place, account for
the fact that a single HIR enum field projection corresponds to two MIR
projection elements: a downcast element and a field element.
Fixes#95271.
Fixes#96299.
Fixes#96512.
Fixes#97378.
r? ``@nikomatsakis`` ``@arora-aman``
Try to cache region_scope_tree as a query
This PR will attempt to restore `region_scope_tree` as a query so that caching works again. It seems that `region_scope_tree` could be re-computed for nested items after all, which could explain the performance regression introduced by #95563.
cc `@Mark-Simulacrum` `@pnkfelix` I will try to trigger a perf run here.
Output correct type responsible for structural match violation
Previously we included the outermost type that caused a structural match violation in the error message and stated that that type must be annotated with `#[derive(Eq, PartialEq)]` even if it already had that annotation. This PR outputs the correct type in the error message.
Fixes https://github.com/rust-lang/rust/issues/97278
Modify MIR building to drop repeat expressions with length zero
Closes#74836 .
Previously, when a user wrote `[foo; 0]` we used to simply leak `foo`. The goal is to fix that. This PR changes MIR building to make `[foo; 0]` equivalent to `{ drop(foo); [] }` in all cases. Of course, this is a breaking change (see below). A crater run did not indicate any regressions though, and given that the previous behavior was almost definitely not what any user wanted, it seems unlikely that anyone was relying on this.
Note that const generics are in general unaffected by this. Inserting the extra `drop` is only meaningful/necessary when `foo` is of a non-`Copy` type, and array repeat expressions with const generic repetition count must always be `Copy`.
Besides the obvious change to behavior associated with the additional drop, there are three categories of examples where this also changes observable behavior. In all of these cases, the new behavior is consistent with what you would get by replacing `[foo; 0]` with `{ drop(foo); [] }`. As such, none of these give the user new powers to express more things.
**No longer allowed in const (breaking)**:
```rust
const _: [String; 0] = [String::new(); 0];
```
This compiles on stable today. Because we now introduce the drop of `String`, this no longer compiles as `String` may not be dropped in a const context.
**Reduced dataflow (non-breaking)**:
```rust
let mut x: i32 = 0;
let r = &x;
let a = [r; 0];
x = 5;
let _b = a;
```
Borrowck rejects this code on stable because it believes there is dataflow between `a` and `r`, and so the lifetime of `r` has to extend to the last statement. This change removes the dataflow and the above code is allowed to compile.
**More const promotion (non-breaking)**:
```rust
let _v: &'static [String; 0] = &[String::new(); 0];
```
This does not compile today because `String` having drop glue keeps it from being const promoted (despite that drop glue never being executed). After this change, this is allowed to compile.
### Alternatives
A previous attempt at this tried to reduce breakage by various tricks. This is still a possibility, but given that crater showed no regressions it seems unclear why we would want to introduce this complexity.
Disallowing `[foo; 0]` completely is also an option, but obviously this is more of a breaking change. I do not know how often this is actually used though.
r? `@oli-obk`
When constructing a MIR from a THIR field expression, introduce an
additional downcast projection before accessing a field of an enum.
When rebasing a place builder on top of a captured place, account for
the fact that a single HIR enum field projection corresponds to two MIR
projection elements: a downcast element and a field element.
correctly deal with user type ascriptions in pat
supersedes #93856
`thir::PatKind::AscribeUserType` previously resulted in `CanonicalUserTypeAnnotations` where the inferred type already had a subtyping relation according to `variance` to the `user_ty`.
The bug can pretty much be summarized as follows:
- during mir building
- `user_ty -> inferred_ty`: considers variance
- `StatementKind::AscribeUserType`: `inferred_ty` is the type of the place, so no variance needed
- during mir borrowck
- `user_ty -> inferred_ty`: does not consider variance
- `StatementKind::AscribeUserType`: applies variance
This mostly worked fine. The lifetimes in `inferred_ty` were only bound by its relation to `user_ty` and to the `place` of `StatementKind::AscribeUserType`, so it doesn't matter where exactly the subtyping happens.
It does however matter when having higher ranked subtying. At this point the place where the subtyping happens is forced, causing this mismatch between building and borrowck to result in unintended errors.
cc #96514 which is pretty much the same issue
r? `@nikomatsakis`
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`
don't encode only locally used attrs
Part of https://github.com/rust-lang/compiler-team/issues/505.
We now filter builtin attributes before encoding them in the crate metadata in case they should only be used in the local crate. To prevent accidental misuse `get_attrs` now requires the caller to state which attribute they are interested in. For places where that isn't trivially possible, I've added a method `fn get_attrs_unchecked` which I intend to remove in a followup PR.
After this pull request landed, we can then slowly move all attributes to only be used in the local crate while being certain that we don't accidentally try to access them from extern crates.
cc https://github.com/rust-lang/rust/pull/94963#issuecomment-1082924289
Use `FxIndexSet` to avoid sorting fake borrows
This fixes#96449, but I haven't yet been able to
make the reproducer work using `#[cfg]` attributes,
so we can't use the 'revision' infra to write a test
The previous implementation relied on sorting by `PlaceRef`.
This requires sorting by a `DefId`, which uses untracked state
(see #93315)
This fixes#96449, but I haven't yet been able to
make the reproducer work using `#[cfg]` attributes,
so we can't use the 'revision' infra to write a test
The previous implementation relied on sorting by `PlaceRef`.
This requires sorting by a `DefId`, which uses untracked state
(see #93315)
Begin fixing all the broken doctests in `compiler/`
Begins to fix#95994.
All of them pass now but 24 of them I've marked with `ignore HELP (<explanation>)` (asking for help) as I'm unsure how to get them to work / if we should leave them as they are.
There are also a few that I marked `ignore` that could maybe be made to work but seem less important.
Each `ignore` has a rough "reason" for ignoring after it parentheses, with
- `(pseudo-rust)` meaning "mostly rust-like but contains foreign syntax"
- `(illustrative)` a somewhat catchall for either a fragment of rust that doesn't stand on its own (like a lone type), or abbreviated rust with ellipses and undeclared types that would get too cluttered if made compile-worthy.
- `(not-rust)` stuff that isn't rust but benefits from the syntax highlighting, like MIR.
- `(internal)` uses `rustc_*` code which would be difficult to make work with the testing setup.
Those reason notes are a bit inconsistently applied and messy though. If that's important I can go through them again and try a more principled approach. When I run `rg '```ignore \(' .` on the repo, there look to be lots of different conventions other people have used for this sort of thing. I could try unifying them all if that would be helpful.
I'm not sure if there was a better existing way to do this but I wrote my own script to help me run all the doctests and wade through the output. If that would be useful to anyone else, I put it here: https://github.com/Elliot-Roberts/rust_doctest_fixing_tool
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`.
Check if call return type is visibly uninhabited when building MIR
The main motivation behind the change is to expose information about diverging
calls to the generator transform and match the precision of drop range tracking
which already understands that call expressions with visibly uninhabited types
diverges.
This change should also accept strictly more programs than before. That is
programs that were previously rejected due to errors raised by control-flow
sensitive checks in a code that is no longer considered reachable.
Fixes#93161.
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>
