compiler: rename BareFn to FnPtr
At some point "BareFn" was the chosen name for a "bare" function, without the niceties of `~fn`, `&fn`, or a few other ways of writing a function type. However, at some point the syntax for a "bare function" and any other function diverged even more. We started calling them what they are: function pointers, denoted by their own syntax.
However, we never changed the *internal* name for these, as this divergence was very gradual. Personally, I have repeatedly searched for "FnPtr" and gotten confused until I find the name is BareFn, only to forget this until the next time, since I don't routinely interact with the higher-level AST and HIR. But even tools that interact with these internal types only touch on them in a few places, making a migration easy enough. Let's use a more intuitive and obvious name, as this 12+ year old name has little to do with current Rust.
Fix some comments and related types and locals where it is obvious, e.g.
- bare_fn -> fn_ptr
- LifetimeBinderKind::BareFnType -> LifetimeBinderKind::FnPtrType
Co-authored-by: León Orell Valerian Liehr <me@fmease.dev>
use `is_multiple_of` and `div_ceil`
In tricky logic, these functions are much more informative than the manual implementations. They also catch subtle bugs:
- the manual `is_multiple_of` often does not handle division by zero
- manual `div_ceil` often does not consider overflow
The transformation is free for `is_multiple_of` if the divisor is compile-time known to be non-zero. For `div_ceil` there is a small cost to considering overflow. Here is some assembly https://godbolt.org/z/5zP8KaE1d.
Remove `ItemKind::descr` method
Follow-up of rust-lang/rust#143234.
After this PR is merged, it will remain two `descr` methods:
* `hir::GenericArg::descr`
* `hir::AssocItemConstraintKind::descr`
For both these enums, I don't think there is the right equivalent in `hir::DefKind` so unless I missed something, we can't remove these two methods because we can't convert these enums into `hir::DefKind`.
r? `@oli-obk`
Port `#[rustc_layout_scalar_valid_range_start/end]` to the new attrib…
Ports `rustc_layout_scalar_valid_range_start` and `rustc_layout_scalar_valid_range_end` to the new attribute parsing infrastructure for https://github.com/rust-lang/rust/issues/131229#issuecomment-2971353197
r? `@jdonszelmann`
Add runtime check to avoid overwrite arg in `Diag`
## Origin PR description
At first, I set up a `debug_assert` check for the arg method to make sure that `args` in `Diag` aren't easily overwritten, and I added the `remove_arg()` method, so that if you do need to overwrite an arg, then you can explicitly call `remove_arg()` to remove it first, then call `arg()` to overwrite it.
For the code before the rust-lang/rust#142015 change, it won't compile because it will report an error
```
arg `instance`already exists.
```
This PR also modifies all diagnostics that fail the check to pass the check. There are two cases of check failure:
1. ~~Between *the parent diagnostic and the subdiagnostic*, or *between the subdiagnostics* have the same field between them. In this case, I renamed the conflicting fields.~~
2. ~~For subdiagnostics stored in `Vec`, the rendering may iteratively write the same arg over and over again. In this case, I changed the auto-generation with `derive(SubDiagnostic)` to manually implementing `SubDiagnostic` and manually rendered it with `eagerly_translate()`, similar to https://github.com/rust-lang/rust/issues/142031#issuecomment-2984812090, and after rendering it I manually deleted useless arg with the newly added `remove_arg` method.~~
## Final Decision
After trying and discussing, we made a final decision.
For `#[derive(Subdiagnostic)]`, This PR made two changes:
1. After the subdiagnostic is rendered, remove all args of this subdiagnostic, which allows for usage like `Vec<Subdiag>`.
2. Store `diag.args` before setting arguments, so that you can restore the contents of the main diagnostic after deleting the arguments after subdiagnostic is rendered, to avoid deleting the main diagnostic's arg when they have the same name args.
Port `#[track_caller]` to the new attribute system
r? ``@oli-obk``
depends on https://github.com/rust-lang/rust/pull/142493Closesrust-lang/rust#142783
(didn't add a test for this, this situation should simply never come up again, the code was simply wrong. lmk if I should add it, but it won't test something very useful)
Add `#[loop_match]` for improved DFA codegen
tracking issue: https://github.com/rust-lang/rust/issues/132306
project goal: https://github.com/rust-lang/rust-project-goals/issues/258
This PR adds the `#[loop_match]` attribute, which aims to improve code generation for state machines. For some (very exciting) benchmarks, see https://github.com/rust-lang/rust-project-goals/issues/258#issuecomment-2732965199
Currently, a very restricted syntax pattern is accepted. We'd like to get feedback and merge this now before we go too far in a direction that others have concerns with.
## current state
We accept code that looks like this
```rust
#[loop_match]
loop {
state = 'blk: {
match state {
State::A => {
#[const_continue]
break 'blk State::B
}
State::B => { /* ... */ }
/* ... */
}
}
}
```
- a loop should have the same semantics with and without `#[loop_match]`: normal `continue` and `break` continue to work
- `#[const_continue]` is only allowed in loops annotated with `#[loop_match]`
- the loop body needs to have this particular shape (a single assignment to the match scrutinee, with the body a labelled block containing just a match)
## future work
- perform const evaluation on the `break` value
- support more state/scrutinee types
## maybe future work
- allow `continue 'label value` syntax, which `#[const_continue]` could then use.
- allow the match to be on an arbitrary expression (e.g. `State::Initial`)
- attempt to also optimize `break`/`continue` expressions that are not marked with `#[const_continue]`
r? ``@traviscross``
