This is a workaround for #122758, but it's not clear why 1.79 requires a
more extensive amount of no_inline than the previous release. Seems like
there's something relatively subtle happening here.
Rewrite select (in the new solver) to use a `ProofTreeVisitor`
We can use a proof tree visitor rather than collecting and recomputing all the nested goals ourselves.
Based on #124415
Cleanup: Replace item names referencing GitHub issues or error codes with something more meaningful
**lcnr** in https://github.com/rust-lang/rust/pull/117164#pullrequestreview-1969935387:
> […] while I know that there's precendent to name things `Issue69420`, I really dislike this as it requires looking up the issue to figure out the purpose of such a variant. Actually referring to the underlying issue, e.g. `AliasMayNormToUncovered` or whatever and then linking to the issue in a doc comment feels a lot more desirable to me. We should ideally rename all the functions and enums which currently use issue numbers.
I've grepped through `compiler/` like crazy and think that I've found all instances of this pattern.
However, I haven't renamed `compute_2229_migrations_*`. Should I?
The first commit introduces an abhorrent and super long name for an item because naming is hard but also scary looking / unwelcoming names are good for things related to temporary-ish backcompat hacks. I'll let you discover it by yourself.
Contains a bit of drive-by cleanup and a diag migration bc that was the simplest option.
r? lcnr or compiler
Because this now always takes place at the start of the function, we can just
use the normal `alloca` method and then initialize each bitmap immediately.
This patch also moves bitmap setup out of the `mcdc_parameters` method, because
there is no longer any particular reason for it to be there.
Lazily normalize inside trait ref during orphan check & consider ty params in rigid alias types to be uncovered
Fixes#99554, fixesrust-lang/types-team#104.
Fixes#114061.
Supersedes #100555.
Tracking issue for the future compatibility lint: #124559.
r? lcnr
Remove many `#[macro_use] extern crate foo` items
This requires the addition of more `use` items, which often make the code more verbose. But they also make the code easier to read, because `#[macro_use]` obscures where macros are defined.
r? `@fee1-dead`
Mention Both HRTB and Generic Lifetime Param in `E0637` documentation
The compiler (rustc 1.77.0) error for `and_without_explicit_lifetime()` in the erroneous code example suggests using a HRTB. But, the corrected example uses an explicit lifetime parameter.
This PR fixes it so that the documentation and the compiler suggestion for error code `E0637` are consistent with each other.
coverage: Split off `mappings.rs` from `spans.rs` and `from_mir.rs`
Originally, `spans.rs` was mainly concerned with extracting and post-processing spans from MIR, so that they could be used for block coverage instrumentation.
Over time it has organically expanded to include more responsibilities, especially relating to branch coverage and MC/DC coverage, that don't really fit its current name.
This PR therefore takes all the extra code that is *not* part of the old span-refinement engine, and moves it out into a new `mappings.rs` file.
---
No functional changes. I have deliberately avoided doing any follow-up (such as renaming types or functions), because this particular change is very rot-prone, and I want it to be as simple and self-contained as possible.
`@rustbot` label +A-code-coverage
because we are already marking unions `NoPropagation` in
`CanConstProp::check()`. That is enough to prevent any attempts
at const propagating unions and this second check is not needed.
Also improve a comment in `CanConstProp::check()`
Split mcdc code to a sub module of coverageinfo
A further work from #124217 . I have made relatively large changes when working on #124278 so that it would better split them from `coverageinfo.rs` to avoid potential troubling merge work with improved branch coverage by `@Zalathar` .
Besides `BlockMarkerGenerator` is added to avoid ownership problems (mostly needed for following change of #124278 )
All code changes are done in [a37d737a](a3d737a086) while the second commit just renames the file.
cc `@RenjiSann` `@Zalathar`
This will impact your current work.
and replace it with a simple note suggesting
returning a value.
The type mismatch error was never due to
how many times the loop iterates. It is more
because of the peculiar structure of what the for
loop desugars to. So the note talking about
iteration count didn't make sense
Rollup of 4 pull requests
Successful merges:
- #124519 (adapt a codegen test for llvm 19)
- #124524 (Add StaticForeignItem and use it on ForeignItemKind)
- #124540 (Give proof tree visitors the ability to instantiate nested goals directly)
- #124543 (codegen tests: Tolerate `range()` qualifications in enum tests)
r? `@ghost`
`@rustbot` modify labels: rollup
Give proof tree visitors the ability to instantiate nested goals directly
Useful when we want to look at the nested goals but not necessarily visit them (e.g. in select).
r? lcnr
Add StaticForeignItem and use it on ForeignItemKind
This is in preparation for unsafe extern blocks that adds a safe variant for functions inside extern blocks.
r? `@oli-obk`
cc `@compiler-errors`
coverage: Replace boolean options with a `CoverageLevel` enum
After #123409, and some discussion at https://github.com/rust-lang/rust/issues/79649#issuecomment-2042093553 and #124120, it became clear to me that we should have a unified concept of “coverage level”, instead of having several separate boolean flags that aren't actually independent.
This PR therefore introduces a `CoverageLevel` enum, to replace the existing boolean flags for `branch` and `mcdc`.
The `no-branch` value (for `-Zcoverage-options`) has been renamed to `block`, instructing the compiler to only instrument for block coverage, with no branch coverage or MD/DC instrumentation.
`@rustbot` label +A-code-coverage
cc `@ZhuUx` `@Lambdaris` `@RenjiSann`
Add a note to the ArbitraryExpressionInPattern error
The current "arbitrary expressions aren't allowed in patterns" error is confusing, as it fires for code where it *looks* like a pattern but the compiler still treats it as an expression. That this is due to the `:expr` fragment specifier forcing the expression-ness property on the code.
In the test suite, the "arbitrary expressions aren't allowed in patterns" error can only be found in combination with macro_rules macros that force expression-ness of their content, namely via `:expr` metavariables. I also can't come up with cases where there would be an expression instead of a pattern, so I think it's always coming from an `:expr`.
In order to make the error less confusing, this adds a note explaining the weird `:expr` fragment behaviour.
Fixes#99380
Remove optionality from MoveData::base_local
This is an artifact from when Places could be based on statics and not just locals. Now, all move paths either are locals or have parents, so this doesn't need to return Option anymore.
[Refactor] Rename `Lint` and `LintGroup`'s `is_loaded` to `is_externally_loaded`
The field being named `is_loaded` was very confusing. Turns out it's true for lints that are registered by external tools like Clippy (I had to look at https://github.com/rust-lang/rust/pull/116412 to know what the variable meant). So I renamed `is_loaded` to `is_externally_loaded` and added some docs.
coverage: Avoid hard-coded values when visiting logical ops
This is a tiny little thing that I noticed during the final review of #123409, and I didn't want to hold up the whole PR just for this.
Instead of separately hard-coding the operation being visited, we can get it from the match arm pattern by using an as-pattern.
`@rustbot` label +A-code-coverage
Mark unions non-const-propagatable in `KnownPanicsLint` without calling layout
Fixes#123710
The ICE occurs during the layout calculation of the union `InvalidTag` in #123710 because the following assert fails:5fe8b697e7/compiler/rustc_abi/src/layout.rs (L289-L292)
The layout calculation is invoked by `KnownPanicsLint` when it is trying to figure out which locals it can const prop. Since `KnownPanicsLint` is never actually going to const props unions thanks to PR https://github.com/rust-lang/rust/pull/121628 there's no point calling layout to check if it can. So in this fix I skip the call to layout and just mark the local non-const propagatable if it is a union.
Fix#124478 - offset_of! returns a temporary
This was due to the must_use() call. Adding HIR's `OffsetOf` to the must_use checking within the compiler avoids this issue while maintaining the lint output.
Fixes#124478. `@tgross35`
Use probes more aggressively in new solver
....so that we have the right candidate information when assembling trait and normalizes-to goals.
Also gets rid of misc probes.
r? lcnr
MCDC coverage: support nested decision coverage
#123409 provided the initial MCDC coverage implementation.
As referenced in #124144, it does not currently support "nested" decisions, like the following example :
```rust
fn nested_if_in_condition(a: bool, b: bool, c: bool) {
if a && if b || c { true } else { false } {
say("yes");
} else {
say("no");
}
}
```
Note that there is an if-expression (`if b || c ...`) embedded inside a boolean expression in the decision of an outer if-expression.
This PR proposes a workaround for this cases, by introducing a Decision context stack, and by handing several `temporary condition bitmaps` instead of just one.
When instrumenting boolean expressions, if the current node is a leaf condition (i.e. not a `||`/`&&` logical operator nor a `!` not operator), we insert a new decision context, such that if there are more boolean expressions inside the condition, they are handled as separate expressions.
On the codegen LLVM side, we allocate as many `temp_cond_bitmap`s as necessary to handle the maximum encountered decision depth.
Add decision_depth field to TVBitmapUpdate/CondBitmapUpdate statements
Add decision_depth field to BcbMappingKinds MCDCBranch and MCDCDecision
Add decision_depth field to MCDCBranchSpan and MCDCDecisionSpan
Rename `inhibit_union_abi_opt()` to `inhibits_union_abi_opt()`
`inihibit` seems to suggest that this function will inhibit optimizations whereas `inhibits` correctly indicates that it will merely _check_ that. With `inhibits` if conditions read more naturally e.g.:
```rust
if repr.inhibits_union_abi_opt() {
}
```
Record certainty of `evaluate_added_goals_and_make_canonical_response` call in candidate
Naming subject to bikeshedding, but I will need this when moving `select` to a proof tree visitor.
r? lcnr
Do not ICE on invalid consts when walking mono-reachable blocks
The `bug!` here was written under the logic of "this condition is impossible, right?" except that of course, if the compiler is given code that results in an compile error, then the situation is possible.
So now we just direct errors into the already-existing path for when we can't do a mono-time optimization.
Fix ICE on invalid const param types
Fixes ICE #123863 which occurs because the const param has a type which is not a `bool`, `char` or an integral type.
The ICEing code path begins here in `typeck_with_fallback`: cb3752d20e/compiler/rustc_hir_typeck/src/lib.rs (L167)
The `fallback` invokes the `type_of` query and that eventually ends up calling `ct_infer` from the lowering code over here:
cb3752d20e/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs (L561) and `ct_infer` ICEs at this location: cb3752d20e/compiler/rustc_hir_analysis/src/collect.rs (L392)
To fix the ICE it I'm triggering a `span_delayed_bug` before we hit `ct_infer` if the type of the const param is not one of the supported types
### Edit
On `@lcnr's` suggestion I've changed the approach to not let `ReStatic` region hit the `bug!` in `ct_infer` instead of triggering a `span_delayed_bug`.
Fix substitution parts having a shifted underline in some cases
If two suggestions parts are side by side, the underline's offset:
(WIP PR as an example, not yet pushed)
```
error: expected a pattern, found an expression
--> ./main.rs:4:9
|
4 | 1 + 2 => 3
| ^^^^^ arbitrary expressions are not allowed in patterns
|
help: check the value in an arm guard
|
4 | n if n == 1 + 2 => 3
| ~ +++++++++++++
```
The emitter didn't take into account that the string had shrunk/grown if two substitution parts were side-by-side (surprisingly, there was only one case in the ui testsuite.)
```
help: check the value in an arm guard
|
4 | n if n == 1 + 2 => 3
| ~ +++++++++++++
```
``@rustbot`` label +A-suggestion-diagnostics
ast: Generalize item kind visiting
And avoid duplicating logic for visiting `Item`s with different kinds (regular, associated, foreign).
The diff is better viewed with whitespace ignored.
resolve: Remove two cases of misleading macro call visiting
Macro calls are ephemeral, they should not add anything to the definition tree, even if their AST could contains something with identity.
Thankfully, macro call AST cannot contain anything like that, so these walks are just noops.
In majority of other places in def_collector / build_reduced_graph they are already not visited.
(Also, a minor match reformatting is included.)
`obligations_for_self_ty`: use `ProofTreeVisitor` for nested goals
As always, dealing with proof trees continues to be a hacked together mess. After this PR and #124380 the only remaining blocker for core is https://github.com/rust-lang/trait-system-refactor-initiative/issues/90. There is also a `ProofTreeVisitor` issue causing an ICE when compiling `alloc` which I will handle in a separate PR. This issue likely affects coherence diagnostics more generally.
The core idea is to extend the proof tree visitor to support visiting nested candidates without using a `probe`. We then simply recurse into nested candidates if they are the only potentially applicable candidate for a given goal and check whether the self type matches the expected one.
For that to work, we need to improve `CanonicalState` to also handle unconstrained inference variables created inside of the trait solver. This is done by extending the `var_values` of `CanoncalState` with each fresh inference variables. Furthermore, we also store the state of all inference variables at the end of each probe. When recursing into `InspectCandidates` we then unify the values of all these states.
r? `@compiler-errors`
Remove special-casing for `SimplifiedType` for next solver
It's unnecessary due to the way that we fully normalize the self type before assembly begins.
r? lcnr
These functions are only used in `rustc_builtin_macros`, so it makes
sense for them to live there. This allows them to be changed from `pub`
to `pub(crate)`.
uses a `ProofTreeVisitor` to look into nested
goals when looking at the pending obligations
during hir typeck. Used by closure signature
inference, coercion, and for async functions.
`-Z debug-macros` is "stabilized" by enabling it by default and removing.
`-Z collapse-macro-debuginfo` is stabilized as `-C collapse-macro-debuginfo`.
It now supports all typical boolean values (`parse_opt_bool`) in addition to just yes/no.
Default value of `collapse_debuginfo` was changed from `false` to `external` (i.e. collapsed if external, not collapsed if local).
`#[collapse_debuginfo]` attribute without a value is no longer supported to avoid guessing the default.
Don't ICE when `codegen_select_candidate` returns ambiguity in new solver
Because we merge identical candidates, we may have >1 impl candidate to in `codegen_select_error` but *not* have a trait error.
r? lcnr
Detect borrow error involving sub-slices and suggest `split_at_mut`
```
error[E0499]: cannot borrow `foo` as mutable more than once at a time
--> $DIR/suggest-split-at-mut.rs:13:18
|
LL | let a = &mut foo[..2];
| --- first mutable borrow occurs here
LL | let b = &mut foo[2..];
| ^^^ second mutable borrow occurs here
LL | a[0] = 5;
| ---- first borrow later used here
|
= help: use `.split_at_mut(position)` or similar method to obtain two mutable non-overlapping sub-slices
```
Address most of #58792.
For follow up work, we should emit a structured suggestion for cases where we can identify the exact `let (a, b) = foo.split_at_mut(2);` call that is needed.
Improved code with clippy
I haven't used the bootstrapped compiler, but I think I have made some improvements using clippy. I have already made the following changes to the compiler:
Replaced `self.first().is_digit(10)` with `self.first().is_ascii_digit()` on lines 633, 664, and 680 of compiler/rust_lexer/src/lib.rs.
Removed unnecessary cast on line 262 of compiler/rustc_lexer/src/unescape.rs
Replaced ok_or_else with ok_or on line 303 of compiler/rustc_lexer/src/unescape.rs
Replaced `!std::env::var("RUSTC_BOOTSTRAP").is_ok()` with `std::env::var("RUSTC_BOOTSTRAP").is_err()` on line 4 of compiler/rustc_macros/build.rs
Removed needless borrow for generic argument `env`on line 53 of compiler/rust_llvm/build.rs
```
error[E0499]: cannot borrow `foo` as mutable more than once at a time
--> $DIR/suggest-split-at-mut.rs:13:18
|
LL | let a = &mut foo[..2];
| --- first mutable borrow occurs here
LL | let b = &mut foo[2..];
| ^^^ second mutable borrow occurs here
LL | a[0] = 5;
| ---- first borrow later used here
|
= help: use `.split_at_mut(position)` or similar method to obtain two mutable non-overlapping sub-slices
```
Address most of #58792.
For follow up work, we should emit a structured suggestion for cases where we can identify the exact `let (a, b) = foo.split_at_mut(2);` call that is needed.
Enforce closure args + return type are WF
I found this out when investigating https://github.com/rust-lang/rust/issues/123461#issuecomment-2040894359. Turns out we don't register WF obligations for closure args and return types, leading to the ICE.
~~I think this is a useful thing to check for, but I'd like to check what the fallout is.~~ crater is complete.
~~Worst case, I think we should enforce this across an edition boundary (and possibly eventually migrate this for all editions) -- this should be super easy to do, since this is a check in HIR wfcheck, so it can be made edition dependent.~~ I believe the regressions are manageable enough to not necessitate edition-specific behavior.
Fixes#123461
Set writable and dead_on_unwind attributes for sret arguments
Set the `writable` and `dead_on_unwind` attributes for `sret` arguments. This allows call slot optimization to remove more memcpy's.
See https://llvm.org/docs/LangRef.html#parameter-attributes for the specification of these attributes. In short, the statement we're making here is that:
* The return slot is writable.
* The return slot will not be read if the function unwinds.
Fixes https://github.com/rust-lang/rust/issues/90595.
Provide more context and suggestions in borrowck errors involving closures
Start pointing to where bindings where declared when they are captured in closures:
```
error[E0597]: `x` does not live long enough
--> $DIR/suggest-return-closure.rs:23:9
|
LL | let x = String::new();
| - binding `x` declared here
...
LL | |c| {
| --- value captured here
LL | x.push(c);
| ^ borrowed value does not live long enough
...
LL | }
| -- borrow later used here
| |
| `x` dropped here while still borrowed
```
Suggest cloning in more cases involving closures:
```
error[E0507]: cannot move out of `foo` in pattern guard
--> $DIR/issue-27282-move-ref-mut-into-guard.rs:11:19
|
LL | if { (|| { let mut bar = foo; bar.take() })(); false } => {},
| ^^ --- move occurs because `foo` has type `&mut Option<&i32>`, which does not implement the `Copy` trait
| |
| `foo` is moved here
|
= note: variables bound in patterns cannot be moved from until after the end of the pattern guard
help: consider cloning the value if the performance cost is acceptable
|
LL | if { (|| { let mut bar = foo.clone(); bar.take() })(); false } => {},
| ++++++++
```
Mention when type parameter could be Clone
```
error[E0382]: use of moved value: `t`
--> $DIR/use_of_moved_value_copy_suggestions.rs:7:9
|
LL | fn duplicate_t<T>(t: T) -> (T, T) {
| - move occurs because `t` has type `T`, which does not implement the `Copy` trait
...
LL | (t, t)
| - ^ value used here after move
| |
| value moved here
|
help: if `T` implemented `Clone`, you could clone the value
--> $DIR/use_of_moved_value_copy_suggestions.rs:4:16
|
LL | fn duplicate_t<T>(t: T) -> (T, T) {
| ^ consider constraining this type parameter with `Clone`
...
LL | (t, t)
| - you could clone this value
help: consider restricting type parameter `T`
|
LL | fn duplicate_t<T: Copy>(t: T) -> (T, T) {
| ++++++
```
The `help` is new. On ADTs, we also extend the output with span labels:
```
error[E0507]: cannot move out of static item `FOO`
--> $DIR/issue-17718-static-move.rs:6:14
|
LL | let _a = FOO;
| ^^^ move occurs because `FOO` has type `Foo`, which does not implement the `Copy` trait
|
note: if `Foo` implemented `Clone`, you could clone the value
--> $DIR/issue-17718-static-move.rs:1:1
|
LL | struct Foo;
| ^^^^^^^^^^ consider implementing `Clone` for this type
...
LL | let _a = FOO;
| --- you could clone this value
help: consider borrowing here
|
LL | let _a = &FOO;
| +
```
Suggest cloning captured binding in move closure
```
error[E0507]: cannot move out of `bar`, a captured variable in an `FnMut` closure
--> $DIR/borrowck-move-by-capture.rs:9:29
|
LL | let bar: Box<_> = Box::new(3);
| --- captured outer variable
LL | let _g = to_fn_mut(|| {
| -- captured by this `FnMut` closure
LL | let _h = to_fn_once(move || -> isize { *bar });
| ^^^^^^^^^^^^^^^^ ----
| | |
| | variable moved due to use in closure
| | move occurs because `bar` has type `Box<isize>`, which does not implement the `Copy` trait
| `bar` is moved here
|
help: clone the value before moving it into the closure 1
|
LL ~ let value = bar.clone();
LL ~ let _h = to_fn_once(move || -> isize { value });
|
```
