Add unstable book entries for parts of asm that are not being stabilized
These are extracted from the existing `asm` documentation in the unstable book that will be removed when `asm` is stabilized.
r? ```@joshtriplett```
Delete Utf8Lossy::from_str
This whole type is marked as being for str internals only, but this constructor is never used by str internals. If you had a &str already and wanted to lossy display it or iterate its lossy utf8 chunks, you would simply not use Utf8Lossy because the whole &str is known to be one contiguous valid utf8 chunk.
If code really does need to obtain a value of type &Utf8Lossy somewhere, and has only a &str, `Utf8Lossy::from_bytes(s.as_bytes())` remains available. As currently implemented, there is no performance penalty relative to `from_str` i.e. the Utf8Lossy does not "remember" that it was constructed using `from_str` to bypass later utf8 decoding.
Fix `Vec::reserve_exact` documentation
The documentation previously said the new capacity cannot overflow `usize`, but in fact it cannot exceed `isize::MAX`.
Fix ICE on format string of macro with secondary-label
This generalizes the fix#86104 to also correctly skip `Span::from_inner` for the `secondary_label` of a format macro parsing error as well.
We can alternatively skip the `span_label` diagnostic call for the secondary label as well, since that label probably only makes sense when the _proper_ span is computed.
Fixes#91556
Update documentation to use `from()` to initialize `HashMap`s and `BTreeMap`s
As of Rust 1.56, `HashMap` and `BTreeMap` both have associated `from()` functions. I think using these in the documentation cleans things up a bit. It allows us to remove some of the `mut`s and avoids the Initialize-Then-Modify anti-pattern.
code-cov: generate dead functions with private/default linkage
As discovered in #85461, the MSVC linker treats weak symbols slightly
differently than unix-y linkers do. This causes link.exe to fail with
LNK1227 "conflicting weak extern definition" where as other targets are
able to link successfully.
This changes the dead functions from being generated as weak/hidden to
private/default which, as the LLVM reference says:
> Global values with “private” linkage are only directly accessible by
objects in the current module. In particular, linking code into a module
with a private global value may cause the private to be renamed as
necessary to avoid collisions. Because the symbol is private to the
module, all references can be updated. This doesn’t show up in any
symbol table in the object file.
This fixes the conflicting weak symbols but doesn't address the reason
*why* we have conflicting symbols for these dead functions. The test
cases added in this commit contain a minimal repro of the fundamental
issue which is that the logic used to decide what dead code functions
should be codegen'd in the current CGU doesn't take into account that
functions can be duplicated across multiple CGUs (for instance, in the
case of `#[inline(always)]` functions).
Fixing that is likely to be a more complex change (see
https://github.com/rust-lang/rust/issues/85461#issuecomment-985005805).
Fixes#85461
adjust const_eval_select documentation
"The Rust compiler assumes" indicates that this is language UB, but [I don't think that is a good idea](https://rust-lang.zulipchat.com/#narrow/stream/146212-t-compiler.2Fconst-eval/topic/const_eval_select.20assumptions). This UB would be very hard to test for and looks like a way-too-big footgun. ``@oli-obk`` suggested this is meant to be more like "library UB", so I tried to adjust the docs accordingly.
I also removed all references to "referential transparency". That is a rather vague concept used to mean many different things, and I honestly have no idea what exactly is meant by it in this specific instance. But I assume ``@fee1-dead`` had in their mind a property that all `const fn` code upholds, so by demanding that the runtime code and the const-time code are *observably equivalent*, whatever that property is would also be enforced here.
Cc ``@rust-lang/wg-const-eval``
Fix incorrect stability attributes
These two instances were caught in #90356, but that PR isn't going to be merged. I've extracted these to ensure it's still correct.
``@rustbot`` label: +A-stability +C-cleanup +S-waiting-on-review
```
error[E0759]: `self` has an anonymous lifetime `'_` but it needs to satisfy a `'static` lifetime requirement
--> $DIR/issue-72312.rs:10:24
|
LL | pub async fn start(&self) {
| ^^^^^ this data with an anonymous lifetime `'_`...
...
LL | require_static(async move {
| -------------- ...is required to live as long as `'static` here...
LL | &self;
| ----- ...and is captured here
|
note: `'static` lifetime requirement introduced by this trait bound
--> $DIR/issue-72312.rs:2:22
|
LL | fn require_static<T: 'static>(val: T) -> T {
| ^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0759`.
```
Fix#72312.
This is a follow-up from #91645, regarding [some remarks I made](https://rust-lang.zulipchat.com/#narrow/stream/187312-wg-async-foundations/topic/join!/near/264293660).
Mainly:
- it hides the recursive munching through a private `macro`, to avoid leaking such details (a corollary is getting rid of the need to use `@` to disambiguate);
- it uses a `match` binding, _outside_ the `async move` block, to better match the semantics from function-like syntax;
- it pre-pins the future before calling into `poll_fn`, since `poll_fn`, alone, cannot guarantee that its capture does not move;
- it uses `.ready()?` since it's such a neat pattern;
- it renames `Took` to `Taken` for consistency with `Done`.
