Add a regression test for issue-72793
Adds a regression test for #72793, which is fixed by #75443. Note that this won't close the issue as the snippet still shows ICE with `-Zmir-opt-level=2`. But it makes sense to add a test anyway.
do not apply DerefMut on union field
This implements the part of [RFC 2514](https://github.com/rust-lang/rfcs/blob/master/text/2514-union-initialization-and-drop.md) about `DerefMut`. Unlike described in the RFC, we only apply this warning specifically when doing `DerefMut` of a `ManuallyDrop` field; that is really the case we are worried about here.
@matthewjasper suggested I patch `convert_place_derefs_to_mutable` and `convert_place_op_to_mutable` for this, but I could not find anything to do in `convert_place_op_to_mutable` and this is sufficient to make the test pass. However, maybe there are some other cases this misses? I have no familiarity with this code.
This is a breaking change *in theory*, if someone used `ManuallyDrop<T>` in a union field and relied on automatic `DerefMut`. But on stable this means `T: Copy`, so the `ManuallyDrop` is rather pointless.
Cc https://github.com/rust-lang/rust/issues/55149
diagnostics: shorten paths of unique symbols
This is a step towards implementing a fix for #50310, and continuation of the discussion in [Pre-RFC: Nicer Types In Diagnostics - compiler - Rust Internals](https://internals.rust-lang.org/t/pre-rfc-nicer-types-in-diagnostics/11139). Impressed upon me from previous discussion in #21934 that an RFC for this is not needed, and I should just come up with code.
The recent improvements to `use` suggestions that I've contributed have given rise to this implementation. Contrary to previous suggestions, it's rather simple logic, and I believe it only reduces the amount of cognitive load that a developer would need when reading type errors.
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If a symbol name can only be imported from one place, and as long as it was not glob-imported anywhere in the current crate, we can trim its printed path to the last component.
This has wide implications on error messages with types, for example, shortening `std::vec::Vec` to just `Vec`, as long as there is no other `Vec` importable from anywhere.
the test was sized to match external iteration only, since
vec's in-place collect now uses internal iteration we collect into
a different type now.
Note that any other try-fold based operation such as count() would also
have exceeded the type length limit for that iterator.
Make all methods of `std::net::Ipv4Addr` const
Make the following methods of `std::net::Ipv4Addr` unstable const under the `const_ipv4` feature:
- `octets`
- `is_loopback`
- `is_private`
- `is_link_local`
- `is_global` (unstable)
- `is_shared` (unstable)
- `is_ietf_protocol_assignment` (unstable)
- `is_benchmarking` (unstable)
- `is_reserved` (unstable)
- `is_multicast`
- `is_broadcast`
- `is_documentation`
- `to_ipv6_compatible`
- `to_ipv6_mapped`
This would make all methods of `Ipv6Addr` const.
Of these methods, `is_global`, `is_broadcast`, `to_ipv6_compatible`, and `to_ipv6_mapped` require a change in implementation.
Part of #76205
Improve recovery on malformed format call
The token following a format expression should be a comma. However, when it is replaced with a similar token (such as a dot), then the corresponding error is emitted, but the token is treated as a comma, and the parsing step continues.
r? @petrochenkov
If a symbol name can only be imported from one place for a type, and
as long as it was not glob-imported anywhere in the current crate, we
can trim its printed path and print only the name.
This has wide implications on error messages with types, for example,
shortening `std::vec::Vec` to just `Vec`, as long as there is no other
`Vec` importable anywhere.
This adds a new '-Z trim-diagnostic-paths=false' option to control this
feature.
On the good path, with no diagnosis printed, we should try to avoid
issuing this query, so we need to prevent trimmed_def_paths query on
several cases.
This change also relies on a previous commit that differentiates
between `Debug` and `Display` on various rustc types, where the latter
is trimmed and presented to the user and the former is not.
lexer: Tiny improvement to shebang detection
Lexer now discerns between regular comments and doc comments, so use that.
The change only affects the choice of reported errors.
Make all methods of `std::net::Ipv6Addr` const
Make the following methods of `std::net::Ipv6Addr` unstable const under the `const_ipv6` feature:
- `segments`
- `is_unspecified`
- `is_loopback`
- `is_global` (unstable)
- `is_unique_local`
- `is_unicast_link_local_strict`
- `is_documentation`
- `multicast_scope`
- `is_multicast`
- `to_ipv4_mapped`
- `to_ipv4`
This would make all methods of `Ipv6Addr` const.
Changed the implementation of `is_unspecified` and `is_loopback` to use a `match` instead of `==`, all other methods did not require a change.
All these methods are dependent on `segments`, the current implementation of which requires unstable `const_fn_transmute` ([PR#75085](https://github.com/rust-lang/rust/pull/75085)).
Part of #76205
Give a better error message for duplicate built-in macros
Minor follow-up to https://github.com/rust-lang/rust/pull/75176 giving a better error message for duplicate builtin macros. This would have made it a little easier to debug.
r? @petrochenkov
Makes the following methods of `std::net::Ipv4Addr` unstable const under the `const_ipv4` feature:
- `is_global`
- `is_reserved`
- `is_broadcast`
- `to_ipv6_compatible`
- `to_ipv6_mapped`
This results in all methods of `Ipv4Addr` being const.
Also adds tests for these methods in a const context.
Run cfg-stripping on generic parameters before invoking derive macros
Fixes#75930
This changes the tokens seen by a proc-macro. However, ising a `#[cfg]` attribute
on a generic paramter is unusual, and combining it with a proc-macro
derive is probably even more unusual. I don't expect this to cause any
breakage.
Previously, this would say no such macro existed, but this was
misleading, since the macro _did_ exist, it was just already seen.
- Say where the macro was previously defined
- Add long-form error message
Make `cow_is_borrowed` methods const
Constify the following methods of `alloc::borrow::Cow`:
- `is_borrowed`
- `is_owned`
Analogous to the const methods `is_some` and `is_none` for Option, and `is_ok` and `is_err` for Result.
These methods are still unstable under `cow_is_borrowed`.
Possible because of #49146 (Allow if and match in constants).
Tracking issue: #65143
Add `-Z proc-macro-backtrace` to allow showing proc-macro panics
Fixes#75050
Previously, we would unconditionally suppress the panic hook during
proc-macro execution. This commit adds a new flag
`-Z proc-macro-backtrace`, which allows running the panic hook for
easier debugging.
Fixes#75050
Previously, we would unconditionally suppress the panic hook during
proc-macro execution. This commit adds a new flag
-Z proc-macro-backtrace, which allows running the panic hook for
easier debugging.
Make some Ordering methods const
Constify the following methods of `core::cmp::Ordering`:
- `reverse`
- `then`
Possible because of #49146 (Allow `if` and `match` in constants).
Tracking issue: #76113
Previous implementation used the `Parser::parse_expr` function in order
to extract the format expression. If the first comma following the
format expression was mistakenly replaced with a dot, then the next
format expression was eaten by the function, because it looked as a
syntactically valid expression, which resulted in incorrectly spanned
error messages.
The way the format expression is exctracted is changed: we first look at
the first available token in the first argument supplied to the
`format!` macro call. If it is a string literal, then it is promoted as
a format expression immediatly, otherwise we fall back to the original
`parse_expr`-related method.
This allows us to ensure that the parser won't consume too much tokens
when a typo is made.
A test has been created so that it is ensured that the issue is properly
fixed.
Fixes#75930
This changes the tokens seen by a proc-macro. However, ising a `#[cfg]` attribute
on a generic paramter is unusual, and combining it with a proc-macro
derive is probably even more unusual. I don't expect this to cause any
breakage.
Fix another clashing_extern_declarations false positive.
Fixes#75739.
Fix another clashing_extern_declarations false positive, this time for transparent newtype with a non-zero member.
r? @lcnr
Abort when foreign exceptions are caught by catch_unwind
Prior to this PR, foreign exceptions were not caught by catch_unwind, and instead passed through invisibly. This represented a painful soundness hole in some libraries ([take_mut](https://github.com/Sgeo/take_mut/blob/master/src/lib.rs#L37)), which relied on `catch_unwind` to handle all possible exit paths from a closure.
With this PR, foreign exceptions are now caught by `catch_unwind` and will trigger an abort since catching foreign exceptions is currently UB according to the latest proposals by the FFI unwind project group.
cc @rust-lang/wg-ffi-unwind
