Provide io::Seek::rewind
Using `Seek::seek` is slightly clumsy because of the need to write (or import) `std::io::SeekFrom` to get at `SeekStart`. C already has `rewind` (although with broken error handling); we should have it too.
I'm motivated to do this because I've just found myself copy-pasting my 5-line extension trait between projects.
That the example ends up using `OpenOptions` makes this look like a niche use case, but it is very common to rewind temporary files. `tempfile` isn't available for use in this example or it would have looked shorter and more natural.
If this gets a positive reception I will open a tracking issue and update the feature gate.
ensure failing promoteds in const/static bodies are handled correctly
`const`/`static` bodies are the one case where we still promote code that might fail to evaluate. Ensure that this is handled correctly; in particular, it must not fail compilation.
`src/test/ui/consts/const-eval/erroneous-const.rs` ensures that when a non-promoted fails to evaluate, we *do* show an error.
r? `@oli-obk`
Make unchecked_{add,sub,mul} inherent methods unstably const
The intrinsics are marked as being stably const (even though they're not stable by nature of being intrinsics), but the currently-unstable inherent versions are not marked as const. This fixes this inconsistency. Split out of #85017,
r? `@oli-obk`
Fix suggestions for missing return type lifetime specifiers
This pull request aims to fix#84592. The issue is that the current code seems to assume that there is only a single relevant span pointing to the missing lifetime, and only looks at the first one:
e5f83d24ae/compiler/rustc_resolve/src/late/lifetimes.rs (L2959)
This is incorrect, though, and leads to incorrect error messages and invalid suggestions. For instance, the example from #84592:
```rust
struct TwoLifetimes<'x, 'y> {
x: &'x (),
y: &'y (),
}
fn two_lifetimes_needed(a: &(), b: &()) -> TwoLifetimes<'_, '_> {
TwoLifetimes { x: &(), y: &() }
}
```
currently leads to:
```
error[E0106]: missing lifetime specifiers
--> src/main.rs:6:57
|
6 | fn two_lifetimes_needed(a: &(), b: &()) -> TwoLifetimes<'_, '_> {
| --- --- ^^ expected 2 lifetime parameters
|
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `a` or `b`
help: consider introducing a named lifetime parameter
|
6 | fn two_lifetimes_needed<'a>(a: &'a (), b: &'a ()) -> TwoLifetimes<'_<'a, 'a>, '_> {
| ^^^^ ^^^^^^ ^^^^^^ ^^^^^^^^^^
```
There are two problems:
- The error message is wrong. There is only _one_ lifetime parameter expected at the location pointed to by the error message (and another one at a separate location).
- The suggestion is incorrect and will not lead to correct code.
With the changes in this PR, I get the following output:
```
error[E0106]: missing lifetime specifiers
--> p.rs:6:57
|
6 | fn two_lifetimes_needed(a: &(), b: &()) -> TwoLifetimes<'_, '_> {
| --- --- ^^ ^^ expected named lifetime parameter
| |
| expected named lifetime parameter
|
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `a` or `b`
help: consider introducing a named lifetime parameter
|
6 | fn two_lifetimes_needed<'a>(a: &'a (), b: &'a ()) -> TwoLifetimes<'a, 'a> {
| ^^^^ ^^^^^^ ^^^^^^ ^^ ^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0106`.
```
Mainly, I changed `add_missing_lifetime_specifiers_label()` to receive a _vector_ of spans (and counts) instead of just one, and adjusted its body accordingly.
rustc_session: Move more option building code from the `options!` macro
The moved code doesn't need to be generated by a macro, it can use a regular (generic) function and type aliases instead.
(The refactoring is salvaged from a branch with different now abandoned work.)
Add primary marker on codegen unit and generate main wrapper on primary codegen.
This is the codegen part of changes extracted from #84062.
This add a marker called `primary` on each codegen units, where exactly one codegen unit will be `primary = true` at a time. This specific codegen unit will take charge of generating `main` wrapper when `main` is imported from a foreign crate after the implementation of RFC 1260.
cc #28937
I'm not sure who should i ask for review for codegen changes, so feel free to reassign.
r? `@nagisa`
Add default search path to `Target::search()`
The function `Target::search()` accepts a target triple and returns a `Target` struct defining the requested target.
There is a `// FIXME 16351: add a sane default search path?` comment that indicates it is desirable to include some sort of default. This was raised in https://github.com/rust-lang/rust/issues/16351 which was closed without any resolution.
https://github.com/rust-lang/rust/pull/31117 was proposed, however that has platform-specific logic that is unsuitable for systems without `/etc/`.
This patch implements the suggestion raised in https://github.com/rust-lang/rust/issues/16351#issuecomment-180878193 where a `target.json` file may be placed in `$(rustc --print sysroot)/lib/rustlib/<target-triple>/target.json`. This allows shipping a toolchain distribution as a single file that gets extracted to the sysroot.
Improve support for NewPM
This adds various missing bits of support for NewPM and allows us to successfully run stage 2 tests with NewPM enabled.
This does not yet enable NewPM by default, as there are still known issue on LLVM 12 (such as a weak fat LTO pipeline). The plan is to make the switch after we update to LLVM 13.
Remove dead or useless code from Session
This is a more principled follow-up to https://github.com/rust-lang/rust/pull/83185#discussion_r601753839.
- Rename `Parser::span_fatal_err` -> `Parser::span_err`
- Remove some unnecessary uses of `struct_span_fatal`
- Make `Diagnostic::span_fatal` unconditionally raise an error
- Add `impl Deref<Target = Handler>` for Session and remove all functions that are exactly the same as their Handler counterparts
- Note why `Handler::fatal` is different from `Sesssion::fatal`
- Remove unused `opt_span_warn` function
r? `@oli-obk` or `@estebank`
Remove `FakeDefId::expect_local()`
This function returned a fake `DefIndex`, with no indication that it was
fake, when it was provided with a `FakeDefId::Fake`. Every use of the
function uses the returned `DefIndex` in a call to
`tcx.local_def_id_to_hir_id()`, which I'm pretty sure would panic if it
were given a fake `DefIndex`.
I removed the function and replaced all calls to it with a call to
`expect_real()` followed by `DefId::expect_local()` (that's a function
on the *real* `DefId`).
Now, in the case that the function is not inlined, the panic location
will be the caller's location, which is more helpful since the panic is
not `expect_real()`'s fault.
This function returned a fake `DefIndex`, with no indication that it was
fake, when it was provided with a `FakeDefId::Fake`. Every use of the
function uses the returned `DefIndex` in a call to
`tcx.local_def_id_to_hir_id()`, which I'm pretty sure would panic if it
were given a fake `DefIndex`.
I removed the function and replaced all calls to it with a call to
`expect_real()` followed by `DefId::expect_local()` (that's a function
on the *real* `DefId`).
Bump stdarch submodule
Major changes:
- More AVX-512 intrinsics.
- More ARM & AArch64 NEON intrinsics.
- Updated unstable WASM intrinsics to latest draft standards.
- Intrinsics that previously used `#[rustc_args_required_const]` now use const generics. See #83167 for more details.
- `std_detect` is now a separate crate instead of a submodule of `std`.
