Rollup of 6 pull requests
Successful merges:
- #110454 (Require impl Trait in associated types to appear in method signatures)
- #111096 (Add support for `cfg(overflow_checks)`)
- #111451 (Note user-facing types of coercion failure)
- #111469 (Fix data race in llvm source code coverage)
- #111494 (Encode `VariantIdx` so we can decode ADT variants in the right order)
- #111499 (asm: loongarch64: Drop efiapi)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Encode `VariantIdx` so we can decode ADT variants in the right order
As far as I can tell, we don't guarantee anything about the ordering of `DefId`s and module children...
The code that motivated this PR (#111483) looks something like:
```rust
#[derive(Protocol)]
pub enum Data {
#[protocol(discriminator(0x00))]
Disconnect(Disconnect),
EncryptionRequest,
/* more variants... */
}
```
The specific macro ([`protocol`](https://github.com/dylanmckay/protocol)) doesn't really matter, but as far as I can tell (from calls to `build_reduced_graph`), the presence of that `#[protocol(..)]` helper attribute causes the def-id of the `Disconnect` enum variant to be collected *after* its siblings, and it shows up after the other variants in `module_children`.
When we decode the variants for `Data` in a child crate (an example test, in this case), this means that the `Disconnect` variant is moved to the end of the variants list, and all of the other variants now have incorrect relative discriminant data, causing the ICE.
This PR fixes this by sorting manually by variant index after they are decoded. I guess there are alternative ways of fixing this, such as not reusing `module_children_non_reexports` to encode the order-sensitive ADT variants, or to do some sorting in `rustc_resolve`... but none of those seemed particularly satisfying either.
~I really struggled to create a reproduction here -- it required at least 3 crates, one of which is a proc macro, and then some code to actually compute discriminants in the child crate... Needless to say, I failed to repro this in a test, but I can confirm that it fixes the regression in #111483.~ Test exists now.
r? `@petrochenkov` but feel free to reassign. ~Again, sorry for no test, but I hope the explanation at least suggests why a fix like this is likely necessary.~ Feedback is welcome.
Fix data race in llvm source code coverage
Fixes#91092 .
Before this patch, increment of counters for code coverage looks like this:
```
movq .L__profc__RNvCsd6wgJFC5r19_3lib6bugaga+8(%rip), %rax
addq $1, %rax
movq %rax, .L__profc__RNvCsd6wgJFC5r19_3lib6bugaga+8(%rip)
```
after this patch:
```
lock incq .L__profc__RNvCs3JgIB2SjHh2_3lib6bugaga+8(%rip)
```
Note user-facing types of coercion failure
When coercing, for example, `Box<A>` into `Box<dyn B>`, make sure that any failure notes mention *those* specific types, rather than mentioning inner types, like "the cast from `A` to `dyn B`".
I expect end-users are often confused when we skip layers of types and only mention the "innermost" part of a coercion, especially when other notes point at HIR, e.g. #111406.
Add support for `cfg(overflow_checks)`
This PR adds support for detecting if overflow checks are enabled in similar fashion as `debug_assertions` are detected. Possible use-case of this, for example, if we want to use checked integer casts in builds with overflow checks, e.g.
```rust
pub fn cast(val: usize)->u16 {
if cfg!(overflow_checks) {
val.try_into().unwrap()
}
else{
vas as _
}
}
```
Resolves#91130.
Require impl Trait in associated types to appear in method signatures
This implements the limited version of TAIT that was proposed in https://github.com/rust-lang/rust/issues/107645#issuecomment-1477899536
Similar to `impl Trait` in return types, `impl Trait` in associated types may only be used within the impl block which it is a part of. To make everything simpler and forward compatible to getting desugared to a plain type alias impl trait in the future, we're requiring that any associated functions or constants that want to register hidden types must be using the associated type in their signature (type of the constant or argument/return type of the associated method. Where bounds mentioning the associated type are ignored).
We have preexisting tests checking that this works transitively across multiple associated types in situations like
```rust
impl Foo for Bar {
type A = impl Trait;
type B = impl Iterator<Item = Self::A>;
fn foo() -> Self::B { ...... }
}
```
A couple of codegen tests are doing
```
// CHECK-NOT: slice_index_len_fail
```
However, that function no longer exists: [the only places](https://github.com/search?q=repo%3Arust-lang%2Frust+slice_index_len_fail&type=code) it occurs in the repo are in those tests.
So this PR updates the tests to check for the absense of the functions that are actually used today to panic for out-of-bounds indexing.
PhantomData: fix documentation wrt interaction with dropck
As far as I could find out, the `PhantomData`-dropck interaction *only* affects code using `may_dangle`. The documentation in the standard library has not been updated for 8 years and thus stems from a time when Rust still used "parametric dropck", before [RFC 1238](https://rust-lang.github.io/rfcs/1238-nonparametric-dropck.html). Back then what the docs said was correct, but with `may_dangle` dropck it stopped being entirely accurate and these days, with NLL, it is actively misleading.
Fixes https://github.com/rust-lang/rust/issues/102810
Fixes https://github.com/rust-lang/rust/issues/70841
Cc `@nikomatsakis` I hope what I am saying here is right.^^
update Miri
and run mir-opt-level=4 tests in rustc CI so issues like https://github.com/rust-lang/rust/issues/111422 are caught before they land.
r? `@oli-obk` due to the bootstrap changes
Reduce BitSet size used in `Borrows` dataflow analysis
It looks like it is not needed to multiply the number of borrows by 2. Bits greater than `self.borrow_set.len()` are never set in this bitset. This should decrease the memory usage by an epsilon.
Uplift `clippy::{drop,forget}_{ref,copy}` lints
This PR aims at uplifting the `clippy::drop_ref`, `clippy::drop_copy`, `clippy::forget_ref` and `clippy::forget_copy` lints.
Those lints are/were declared in the correctness category of clippy because they lint on useless and most probably is not what the developer wanted.
## `drop_ref` and `forget_ref`
The `drop_ref` and `forget_ref` lint checks for calls to `std::mem::drop` or `std::mem::forget` with a reference instead of an owned value.
### Example
```rust
let mut lock_guard = mutex.lock();
std::mem::drop(&lock_guard) // Should have been drop(lock_guard), mutex
// still locked
operation_that_requires_mutex_to_be_unlocked();
```
### Explanation
Calling `drop` or `forget` on a reference will only drop the reference itself, which is a no-op. It will not call the `drop` or `forget` method on the underlying referenced value, which is likely what was intended.
## `drop_copy` and `forget_copy`
The `drop_copy` and `forget_copy` lint checks for calls to `std::mem::forget` or `std::mem::drop` with a value that derives the Copy trait.
### Example
```rust
let x: i32 = 42; // i32 implements Copy
std::mem::forget(x) // A copy of x is passed to the function, leaving the
// original unaffected
```
### Explanation
Calling `std::mem::forget` [does nothing for types that implement Copy](https://doc.rust-lang.org/std/mem/fn.drop.html) since the value will be copied and moved into the function on invocation.
-----
Followed the instructions for uplift a clippy describe here: https://github.com/rust-lang/rust/pull/99696#pullrequestreview-1134072751
cc `@m-ou-se` (as T-libs-api leader because the uplifting was discussed in a recent meeting)
use by ref TokenTree iterator to avoid a few clones
Just a handful of swaps from the by-value cursor to by-ref cursor so as to avoid some unnecessary clones.
I've been doing some analysis on internal cleanup opportunities within rustfmt and as part of that yak-shave I found myself perusing broader token stream and tree usage (which we use within rustfmt). As reflected in some inline comments on the cursor structs (not part of this diff), there's probably many other such cases throughout the code, but figured I'd start small with these while I had the time. May take a look at the other sites in the future
Don't ICE in layout computation for placeholder types
We use `layout_of` for the built-in `PointerLike` trait to check if a type can be coerced to a `dyn*`.
Since the new solver canonicalizes parameter types to placeholders, that code needs to be able to treat placeholders like params, and for the most part it does, **except** for a call to `is_trivially_sized`. This PR fixes that.
Verify copies of mutable pointers in 2 stages in ReferencePropagation
Fixes#111422
In the first stage, we mark the copies as reborrows, to be checked later.
In the second stage, we walk the reborrow chains to verify that all stages are fully replacable.
The replacement itself mirrors the check, and iterates through the reborrow chain.
r? ``````@RalfJung``````
cc ``````@JakobDegen``````
bump windows crate 0.46 -> 0.48
This drops duped version of crate(0.46), reduces `rustc_driver.dll` ~800kb and reduces exported functions number from 26k to 22k.
Also while here, added `tidy-alphabetical` sorting to lists in tidy allowed lists.
Fix instrument-coverage tests by using Python to sort instantiation groups
#110942 was intended to fix a set of `-Cinstrument-coverage` tests, but it ended up silently *breaking* those tests on Linux, for annoying reasons detailed at #111171.
Dealing with `diff --ignore-matching-lines` across multiple platforms has been such a hassle that I've instead written a simple Python script that can detect instantiation groups in the output of `llvm-cov show`, and sort them in a predictable order so that they can be used as snapshots for an ordinary invocation of `diff`.
This approach should be much less error-prone, because it can't accidentally ignore the wrong lines, and any unforeseen problems will tend to result in a Python exception or a failing diff.
