Revert "Do not hash leading zero bytes of i64 numbers in Sip128 hasher"
Reverts rust-lang/rust#92103. It had a (in retrospect, obvious) correctness problem where changing the order of two adjacent values would produce identical hashes, which is problematic in stable hashing (see [this comment](https://github.com/rust-lang/rust/pull/92103#issuecomment-1014625442)).
I'll try to send the PR again with a fix for this issue.
r? `@the8472`
Check `const Drop` impls considering `~const` Bounds
This PR adds logic to trait selection to account for `~const` bounds in custom `impl const Drop` for types, elaborates the `const Drop` check in `rustc_const_eval` to check those bounds, and steals some drop linting fixes from #92922, thanks `@DrMeepster.`
r? `@fee1-dead` `@oli-obk` <sup>(edit: guess I can't request review from two people, lol)</sup>
since each of you wrote and reviewed #88558, respectively.
Since the logic here is more complicated than what existed, it's possible that this is a perf regression. But it works correctly with tests, and that makes me happy.
Fixes#92881
Liberate late bound regions when collecting GAT substs in wfcheck
The issue here is that the [`GATSubstCollector`](https://github.com/rust-lang/rust/blob/master/compiler/rustc_typeck/src/check/wfcheck.rs#L604) does not currently do anything wrt `Binder`s, so the GAT substs it copies out have escaping late bound regions when it walks through types like `for<'x> fn() -> Self::Gat<'x>`.
I made that visitor call `liberate_late_bound_regions`, not sure if that's the right thing here or we need to do something else to replace these bound vars with placeholders. I'm not familiar with other code doing anything similar.. But the issue is indeed no longer ICEing.
Fixes#92954
r? `@jackh726`
since you last touched this code, feel free to reassign
Normalize field access types during borrowck
I think a normalize was just left out here, since we normalize analogously throughout this file.
Fixes#93141
Disable drop range tracking in generators
Generator drop tracking caused an ICE for generators involving the Never type (Issue #93161). Since this breaks a test case with miri, we temporarily disable drop tracking so miri is unblocked while we properly fix the issue.
impl Not for !
The lack of this impl caused trouble for me in some degenerate cases of macro-generated code of the form `if !$cond {...}`, even without `feature(never_type)` on a stable compiler. Namely if `$cond` contains a `return` or `break` or similar diverging expression, which would otherwise be perfectly legal in boolean position, the code previously failed to compile with:
```console
error[E0600]: cannot apply unary operator `!` to type `!`
--> library/core/tests/ops.rs:239:8
|
239 | if !return () {}
| ^^^^^^^^^^ cannot apply unary operator `!`
```
Reject unsupported naked functions
Transition unsupported naked functions future incompatibility lint into an error:
* Naked functions must contain a single inline assembly block. Introduced as future incompatibility lint in 1.50 #79653. Change into an error fixes a soundness issue described in #32489.
* Naked functions must not use any forms of inline attribute. Introduced as future incompatibility lint in 1.56 #87652.
Closes#32490.
Closes#32489.
r? ```@Amanieu``` ```@npmccallum``` ```@joshtriplett```
Improve string concatenation suggestion
Before:
error[E0369]: cannot add `&str` to `&str`
--> file.rs:2:22
|
2 | let _x = "hello" + " world";
| ------- ^ -------- &str
| | |
| | `+` cannot be used to concatenate two `&str` strings
| &str
|
help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
|
2 | let _x = "hello".to_owned() + " world";
| ~~~~~~~~~~~~~~~~~~
After:
error[E0369]: cannot add `&str` to `&str`
--> file.rs:2:22
|
2 | let _x = "hello" + " world";
| ------- ^ -------- &str
| | |
| | `+` cannot be used to concatenate two `&str` strings
| &str
|
= note: string concatenation requires an owned `String` on the left
help: create an owned `String` from a string reference
|
2 | let _x = "hello".to_owned() + " world";
| +++++++++++
Improve error message for key="value" cfg arguments.
Hi, I ran into difficulties using the `--cfg` flag syntax, first hit when googling for the error was issue https://github.com/rust-lang/rust/issues/66450. Reading that issue, it sounded like the best way to improve the experience was to improve the error message, this is low risk and doesn't introduce any additional argument parsing.
The issue mentions that it is entirely dependent on the shell, while this may be true, I think guiding the the user into the realization that the quotes may need to be escaped is helpful. The two suggested escapings both work in Bash and in the Windows command prompt.
fyi `@ehuss`
Ensure that early-bound function lifetimes are always 'local'
During borrowchecking, we treat any free (early-bound) regions on
the 'defining type' as `RegionClassification::External`. According
to the doc comments, we should only have 'external' regions when
checking a closure/generator.
However, a plain function can also have some if its regions
be considered 'early bound' - this occurs when the region is
constrained by an argument, appears in a `where` clause, or
in an opaque type. This was causing us to incorrectly mark these
regions as 'external', which caused some diagnostic code
to act as if we were referring to a 'parent' region from inside
a closure.
This PR marks all instantiated region variables as 'local'
when we're borrow-checking something other than a
closure/generator/inline-const.
Override rustc version in ui and mir-opt tests to get stable hashes
Building a dozen separate regexps for each test in compiletest consumes significant amounts of CPU cycles.
UI test timings on my machine:
OLD: 39.63s
NEW: 30.27s
Generator drop tracking caused an ICE for generators involving the Never
type (Issue #93161). Since this breaks miri, we temporarily disable drop
tracking so miri is unblocked while we properly fix the issue.
Rollup of 17 pull requests
Successful merges:
- #91032 (Introduce drop range tracking to generator interior analysis)
- #92856 (Exclude "test" from doc_auto_cfg)
- #92860 (Fix errors on blanket impls by ignoring the children of generated impls)
- #93038 (Fix star handling in block doc comments)
- #93061 (Only suggest adding `!` to expressions that can be macro invocation)
- #93067 (rustdoc mobile: fix scroll offset when jumping to internal id)
- #93086 (Add tests to ensure that `let_chains` works with `if_let_guard`)
- #93087 (Fix src/test/run-make/raw-dylib-alt-calling-convention)
- #93091 (⬆ chalk to 0.76.0)
- #93094 (src/test/rustdoc-json: Check for `struct_field`s in `variant_tuple_struct.rs`)
- #93098 (Show a more informative panic message when `DefPathHash` does not exist)
- #93099 (rustdoc: auto create output directory when "--output-format json")
- #93102 (Pretty printer algorithm revamp step 3)
- #93104 (Support --bless for pp-exact pretty printer tests)
- #93114 (update comment for `ensure_monomorphic_enough`)
- #93128 (Add script to prevent point releases with same number as existing ones)
- #93136 (Backport the 1.58.1 release notes to master)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Transition unsupported naked functions future incompatibility lint into
an error:
* Naked functions must contain a single inline assembly block.
Introduced as future incompatibility lint in 1.50 #79653.
Change into an error fixes a soundness issue described in #32489.
* Naked functions must not use any forms of inline attribute.
Introduced as future incompatibility lint in 1.56 #87652.
Building a dozen separate regexps for each test in compiletest consumes significant amounts of CPU cycles.
Using `RUSTC_FORCE_INCR_COMP_ARTIFACT_HEADER` stabilizes hashes calcuated for the individual tests so
no test-dependent normalization is needed. Hashes for the standard library still change so some
normalizations are still needed.
Add tests to ensure that `let_chains` works with `if_let_guard`
The current machinery already makes such combination possible but lacks tests.
cc `@matthewjasper`
Introduce drop range tracking to generator interior analysis
This PR addresses cases such as this one from #57478:
```rust
struct Foo;
impl !Send for Foo {}
let _: impl Send = || {
let guard = Foo;
drop(guard);
yield;
};
```
Previously, the `generator_interior` pass would unnecessarily include the type `Foo` in the generator because it was not aware of the behavior of `drop`. We fix this issue by introducing a drop range analysis that finds portions of the code where a value is guaranteed to be dropped. If a value is dropped at all suspend points, then it is no longer included in the generator type. Note that we are using "dropped" in a generic sense to include any case in which a value has been moved. That is, we do not only look at calls to the `drop` function.
There are several phases to the drop tracking algorithm, and we'll go into more detail below.
1. Use `ExprUseVisitor` to find values that are consumed and borrowed.
2. `DropRangeVisitor` uses consume and borrow information to gather drop and reinitialization events, as well as build a control flow graph.
3. We then propagate drop and reinitialization information through the CFG until we reach a fix point (see `DropRanges::propagate_to_fixpoint`).
4. When recording a type (see `InteriorVisitor::record`), we check the computed drop ranges to see if that value is definitely dropped at the suspend point. If so, we skip including it in the type.
## 1. Use `ExprUseVisitor` to find values that are consumed and borrowed.
We use `ExprUseVisitor` to identify the places where values are consumed. We track both the `hir_id` of the value, and the `hir_id` of the expression that consumes it. For example, in the expression `[Foo]`, the `Foo` is consumed by the array expression, so after the array expression we can consider the `Foo` temporary to be dropped.
In this process, we also collect values that are borrowed. The reason is that the MIR transform for generators conservatively assumes anything borrowed is live across a suspend point (see `rustc_mir_transform::generator::locals_live_across_suspend_points`). We match this behavior here as well.
## 2. Gather drop events, reinitialization events, and control flow graph
After finding the values of interest, we perform a post-order traversal over the HIR tree to find the points where these values are dropped or reinitialized. We use the post-order index of each event because this is how the existing generator interior analysis refers to the position of suspend points and the scopes of variables.
During this traversal, we also record branching and merging information to handle control flow constructs such as `if`, `match`, and `loop`. This is necessary because values may be dropped along some control flow paths but not others.
## 3. Iterate to fixed point
The previous pass found the interesting events and locations, but now we need to find the actual ranges where things are dropped. Upon entry, we have a list of nodes ordered by their position in the post-order traversal. Each node has a set of successors. For each node we additionally keep a bitfield with one bit per potentially consumed value. The bit is set if we the value is dropped along all paths entering this node.
To compute the drop information, we first reverse the successor edges to find each node's predecessors. Then we iterate through each node, and for each node we set its dropped value bitfield to the intersection of all incoming dropped value bitfields.
If any bitfield for any node changes, we re-run the propagation loop again.
## 4. Ignore dropped values across suspend points
At this point we have a data structure where we can ask whether a value is guaranteed to be dropped at any post order index for the HIR tree. We use this information in `InteriorVisitor` to check whether a value in question is dropped at a particular suspend point. If it is, we do not include that value's type in the generator type.
Note that we had to augment the region scope tree to include all yields in scope, rather than just the last one as we did before.
r? `@nikomatsakis`
Change lint message to be stronger for &T -> &mut T transmute
The old message implied that it's only UB if you use the reference to mutate, which (as far as I know) is not true. As in, the following program has UB, and a &T -> &mut T transmute is effectively an `unreachable_unchecked`.
```rust
fn main() {
#[allow(mutable_transmutes)]
unsafe {
let _ = std::mem::transmute::<&i32, &mut i32>(&0);
}
}
```
In the future, it might be a good idea to use the edition system to make this a hard error, since I don't think it is *ever* defined behaviour? Unless we rule that `&UnsafeCell<i32> -> &mut i32` is fine. (That, and you always could just use `.get()`, so you're not losing anything)
improve `_` constants in item signature handling
removing the "type" from the error messages does slightly worsen the error messages for types, but figuring out whether the placeholder is for a type or a constant and correctly dealing with that seemed fairly difficult to me so I took the easy way out ✨ Imo the error message is still clear enough.
r? `@BoxyUwU` cc `@estebank`
Point at correct argument when async fn output type lifetime disagrees with signature
Fixes most of #74256.
## Problems fixed
This PR fixes a couple of related problems in the error reporting code.
### Highlighting the wrong argument
First, the error reporting code was looking at the desugared return type of an `async fn` to decide which parameter to highlight. For example, a function like
```rust
async fn async_fn(self: &Struct, f: &u32) -> &u32
{ f }
```
desugars to
```rust
async fn async_fn<'a, 'b>(self: &'a Struct, f: &'b u32)
-> impl Future<Output = &'a u32> + 'a + 'b
{ f }
```
Since `f: &'b u32` is returned but the output type is `&'a u32`, the error would occur when checking that `'a: 'b`.
The reporting code would look to see if the "offending" lifetime `'b` was included in the return type, and because the code was looking at the desugared future type, it was included. So it defaulted to reporting that the source of the other lifetime `'a` (the `self` type) was the problem, when it was really the type of `f`. (Note that if it had chosen instead to look at `'a` first, it too would have been included in the output type, and it would have arbitrarily reported the error (correctly this time) on the type of `f`.)
Looking at the actual future type isn't useful for this reason; it captures all input lifetimes. Using the written return type for `async fn` solves this problem and results in less confusing error messages for the user.
This isn't a perfect fix, unfortunately; writing the "manually desugared" form of the above function still results in the wrong parameter being highlighted. Looking at the output type of every `impl Future` return type doesn't feel like a very principled approach, though it might work. The problem would remain for function signatures that look like the desugared one above but use different traits. There may be deeper changes required to pinpoint which part of each type is conflicting.
### Lying about await point capture causing lifetime conflicts
The second issue fixed by this PR is the unnecessary complexity in `try_report_anon_anon_conflict`. It turns out that the root cause I suggested in https://github.com/rust-lang/rust/issues/76547#issuecomment-692863608 wasn't really the root cause. Adding special handling to report that a variable was captured over an await point only made the error messages less correct and pointed to a problem other than the one that actually occurred.
Given the above discussion, it's easy to see why: `async fn`s capture all input lifetimes in their return type, so holding an argument across an await point should never cause a lifetime conflict! Removing the special handling simplified the code and improved the error messages (though they still aren't very good!)
## Future work
* Fix error reporting on the "desugared" form of this code
* Get the `suggest_adding_lifetime_params` suggestion firing on these examples
* cc #42703, I think
r? `@estebank`
- Also rename a trivial_const_drop to match style of other functions in
the util module.
- Also add a test for `const Drop` that doesn't depend on a `~const`
bound.
- Also comment a bit why we remove the const bound during dropck impl
check.
mangling_v0: Skip extern blocks during mangling
There's no need to include the dummy `Nt` into the symbol name, items in extern blocks belong to their parent modules for all purposes except for inheriting the ABI and attributes.
Follow up to https://github.com/rust-lang/rust/pull/92032
(There's also a drive-by fix to the `rust-demangler` tool's tests, which don't run on CI, I initially attempted using them for testing this PR.)
Formally implement let chains
## Let chains
My longest and hardest contribution since #64010.
Thanks to `@Centril` for creating the RFC and special thanks to `@matthewjasper` for helping me since the beginning of this journey. In fact, `@matthewjasper` did much of the complicated MIR stuff so it's true to say that this feature wouldn't be possible without him. Thanks again `@matthewjasper!`
With the changes proposed in this PR, it will be possible to chain let expressions along side local variable declarations or ordinary conditional expressions. In other words, do much of what the `if_chain` crate already does.
## Other considerations
* `if let guard` and `let ... else` features need special care and should be handled in a following PR.
* Irrefutable patterns are allowed within a let chain context
* ~~Three Clippy lints were already converted to start dogfooding and help detect possible corner cases~~
cc #53667
We previously weren't tracking partial re-inits while being too
aggressive around partial drops. With this change, we simply ignore
partial drops, which is the safer, more conservative choice.
The previous commit made the non_sync_with_method_call case pass due to
the await being unreachable. Unfortunately, this isn't actually the
behavior the test was verifying. This change lifts the panic into a
helper function so that the generator analysis still thinks the await
is reachable, and therefore we preserve the same testing behavior.
