Add enum_intrinsics_non_enums lint
There is a clippy lint to prevent calling [`mem::discriminant`](https://doc.rust-lang.org/std/mem/fn.discriminant.html) with a non-enum type. I think the lint is worthy of being included in rustc, given that `discriminant::<T>()` where `T` is a non-enum has an unspecified return value, and there are no valid use cases where you'd actually want this.
I've also made the lint check [variant_count](https://doc.rust-lang.org/core/mem/fn.variant_count.html) (#73662).
closes#83899
Add #[must_use] to from_value conversions
I added two methods to the list myself. Clippy did not flag them because they take `mut` args, but neither modifies their argument.
```rust
core::str const unsafe fn from_utf8_unchecked_mut(v: &mut [u8]) -> &mut str;
std::ffi::CString unsafe fn from_raw(ptr: *mut c_char) -> CString;
```
I put a custom note on `from_raw`:
```rust
#[must_use = "call `drop(from_raw(ptr))` if you intend to drop the `CString`"]
pub unsafe fn from_raw(ptr: *mut c_char) -> CString {
```
Parent issue: #89692
r? ``@joshtriplett``
Fix RUSTC_LOG handling
Rustc was incorrectly reading the value of `RUSTC_LOG` as the environment vairable with the logging configuration, rather than the logging configuration itself.
Add #[must_use] to alloc constructors
Added `#[must_use]`. to the various forms of `new`, `pin`, and `with_capacity` in the `alloc` crate. No extra explanations given as I couldn't think of anything useful to add.
I figure this deserves extra scrutiny compared to the other PRs I've done so far. In particular:
* The 4 `pin`/`pin_in` methods I touched. Are there legitimate use cases for pinning and not using the result? Pinning's a difficult concept I'm not very comfortable with.
* `Box`'s constructors. Do people ever create boxes just for the side effects... allocating or zeroing out memory?
Parent issue: #89692
r? ``@joshtriplett``
bootstrap: don't use `--merges` to look for commit hashes for downloading artifacts
Shallow clones (and possibly worktrees, though I can't seem to reproduce the problem there) can cause `git rev-list --merges` to falsely return no results, even if a merge commit is present. Stop using the `--merges` option when looking for commit hashes that have build artifacts. `--first-parent` and `--author=bors@rust-lang.org` should be sufficient.
Also exit with an error if the configuration asks for artifacts to be downloaded and we can't determine an appropriate commit hash to use to download artifacts.
Fixes#87890.
r? ``@jyn514``
``@rustbot`` label +A-rustbuild +A-contributor-roadblock
Create more accurate debuginfo for vtables.
Before this PR all vtables would have the same name (`"vtable"`) in debuginfo. Now they get an unambiguous name that identifies the implementing type and the trait that is being implemented.
This is only one of several possible improvements:
- This PR describes vtables as arrays of `*const u8` pointers. It would nice to describe them as structs where function pointer is represented by a field with a name indicative of the method it maps to. However, this requires coming up with a naming scheme that avoids clashes between methods with the same name (which is possible if the vtable contains multiple traits).
- The PR does not update the debuginfo we generate for the vtable-pointer field in a fat `dyn` pointer. Right now there does not seem to be an easy way of getting ahold of a vtable-layout without also knowing the concrete self-type of a trait object.
r? `@wesleywiser`
Rather than compiling rustbuild and all its dependencies with
`debuginfo=2`, this compiles dependencies without debuginfo and
rustbuild with `debuginfo=1`. On my laptop, this brings compile times
down from ~1:20 to ~1:05.
Move `DebuggerCommands` and `check_debugger_output` to a separate module
Work towards #89475.
As part of this move, the public functions were changed to return `Result`. This is so that the error handling that initially took `&self: TestCx` can still use that `TestCx`.
Cleanup src/test/ui/{simd,simd-intrinsic}
Initial motivation was to simplify a huge macro expansion using a tuple, since we can just use an array in `#[repr(simd)]` now for the same result. But also, several tests were going unnoticed during development of SIMD intrinsics because people kept looking in the wrong directory, and many are basically run-pass vs. build-fail versions of the same tests, so let's keep them close together and simplify their names, so they're easier to sift through.
Rustc was incorrectly reading the value of `RUSTC_LOG` as the
environment vairable with the logging configuration, rather than the
logging configuration itself.
