Stabilize backtrace
This PR stabilizes the std::backtrace module. As of #99431, the std::Error::backtrace item has been removed, and so the rest of the backtrace feature is set to be stabilized.
Previous discussion can be found in #72981, #3156.
Stabilized API summary:
```rust
pub mod std {
pub mod backtrace {
pub struct Backtrace { }
pub enum BacktraceStatus {
Unsupported,
Disabled,
Captured,
}
impl fmt::Debug for Backtrace {}
impl Backtrace {
pub fn capture() -> Backtrace;
pub fn force_capture() -> Backtrace;
pub const fn disabled() -> Backtrace;
pub fn status(&self) -> BacktraceStatus;
}
impl fmt::Display for Backtrace {}
}
}
```
`@yaahc`
Set tainted errors bit before emitting coerce suggestions.
Fixes#100246.
#89576 basically got 99% of the way there but the match typechecking code (which calls `coerce_inner`) also needed a similar fix.
Add some high-level docs to `FnCtxt` and `ItemCtxt`
I haven't understood the difference between these before, but
``@compiler-errors`` helped me clear it up. Hopefully this will help other
people who've been confused!
r? `@compiler-errors`
Some "this expression has a field"-related fixes
Each commit does something different and is worth reviewing, but the final diff from `master..HEAD` contains the sum of the changes to the UI tests, since some commits added UI tests "regressions" which were later removed in other commits.
The only change I could see adding on top of this is suppressing `Clone::clone` from the "this expression has a field that has this method" suggestion, since it's so commonly implemented by types that it's not worthwhile suggesting in general.
Error on broken pipe but do not backtrace or ICE
Windows will report a broken pipe as a normal error which in turn `println!` will panic on. Currently this causes rustc to produce a backtrace and ICE. However, this is not a bug with rustc so a backtrace is overly verbose and ultimately unhelpful to the user.
Kind of fixes#98700. Although this is admittedly a bit of a hack because at panic time all we have is a string to inspect. On zulip it was suggested that libstd might someday provide a way to indicate a soft panic but that day isn't today.
consider unnormalized types for implied bounds
extracted, and slightly modified, from #98900
The idea here is that generally, rustc is split into things which can assume its inputs are well formed[^1], and things which have verify that themselves.
Generally most predicates should only deal with well formed inputs, e.g. a `&'a &'b (): Trait` predicate should be able to assume that `'b: 'a` holds. Normalization can loosen wf requirements (see #91068) and must therefore not be used in places which still have to check well formedness. The only such place should hopefully be `WellFormed` predicates
fixes#87748 and #98543
r? `@jackh726` cc `@rust-lang/types`
[^1]: These places may still encounter non-wf inputs and have to deal with them without causing an ICE as we may check for well formedness out of order.
Re-structure the stability checks for library features to avoid calling
`defined_lib_features` for any more crates than necessary for each of
the implications or local feature attributes that need validation.
Don't ICE while suggesting updating item path.
When an item isn't found, we may suggest an appropriate import to `use`. Along with that, we also suggest updating the path to work with the `use`. Unfortunately, if the code in question originates from a macro, the span used to indicate which part of the path needs updating may not be suitable and cause an ICE (*). Since, such code is not adjustable directly by the user without modifying the macro, just skip the suggestion in such cases.
(*) The ICE happens because the emitter want to indicate to the user what code to delete by referencing a certain span. But in this case, said span has `lo == hi == 0` which means it thinks it's a dummy span. Adding a space before the proc macro attribute is enough to stop it from ICE'ing but even then the suggestion doesn't really make any sense:
```
help: if you import `DataStore`, refer to it directly
|
1 - #[dbstruct::dbstruct]
1 + #[dbstruct::dbstruct]
```
Since suggestions are best-effort, I just gated this one on `can_be_used_for_suggestions` which catches cases like this.
Fixes#100199
Don't document impossible to call default trait items on impls
Closes#100176
This only skips documenting _default_ trait items on impls, not ones that are written inside the impl block. This is a conservative approach, since I think we should document all items written in an impl block (I guess unless hidden or whatever), but the existence of this new query I added makes this easy to extend to other rustdoc cases.
Implement `#[rustc_default_body_unstable]`
This PR implements a new stability attribute — `#[rustc_default_body_unstable]`.
`#[rustc_default_body_unstable]` controls the stability of default bodies in traits.
For example:
```rust
pub trait Trait {
#[rustc_default_body_unstable(feature = "feat", isssue = "none")]
fn item() {}
}
```
In order to implement `Trait` user needs to either
- implement `item` (even though it has a default implementation)
- enable `#![feature(feat)]`
This is useful in conjunction with [`#[rustc_must_implement_one_of]`](https://github.com/rust-lang/rust/pull/92164), we may want to relax requirements for a trait, for example allowing implementing either of `PartialEq::{eq, ne}`, but do so in a safe way — making implementation of only `PartialEq::ne` unstable.
r? `@Aaron1011`
cc `@nrc` (iirc you were interested in this wrt `read_buf`), `@danielhenrymantilla` (you were interested in the related `#[rustc_must_implement_one_of]`)
P.S. This is my first time working with stability attributes, so I'm not sure if I did everything right 😅
Add option to `mir::MutVisitor` to not invalidate CFG.
This also applies that option to some uses of the visitor. I had considered a design more similar to #100087 in which we detect if the CFG needs to be invalidated, but that is more difficult with the visitor API and so I decided against it. Another alternative to this design is to offer an API for "saving" and "restoring" CFG caches across arbitrary code. Such an API is more general, and so we may eventually want it anyway, but it seems overkill for this use case.
r? `@tmiasko`
https://reviews.llvm.org/D120026 changed atomics on thumbv6m to
use libatomic, to ensure that atomic load/store are compatible with
atomic RMW/CAS. However, Rust wants to expose only load/store
without libcalls.
https://reviews.llvm.org/D130480 added support for this behind
the +atomics-32 target feature, so enable that feature.
Instead of a FxHashMap<Symbol, (usize, Span)> for the named arguments,
this now includes the name and span in the elements of the
Vec<FormatArg> directly. The FxHashMap still exists to look up the
index, but no longer contains the span. Looking up the name or span of
an argument is now trivial and does not need the map anymore.
Implement special-cased projection error message for some common traits
Not sure what the best phrasing is, but I feel like these are more clear than the plain `<Type as Iterator>::Output == Type` messages.
If this is actually a good idea, are there any other traits this could benefit?
