Deduplicate higher-ranked lifetime capture errors in impl Trait
Previously, when an `impl Trait` captured multiple higher-ranked
lifetimes from an outer `impl Trait`, the compiler would emit a
separate error for each captured lifetime. This resulted in verbose
and confusing diagnostics, especially in edition 2024 where implicit
captures caused duplicate errors.
This commit introduces error accumulation that collects all capture
spans and lifetime declaration spans, then emits a single consolidated
diagnostic using MultiSpan. The new error shows all captured lifetimes
with visual indicators and lists all declarations in a single note.
r? `@estebank`
Fixes https://github.com/rust-lang/rust/issues/143022
Previously we only showed the trait's assoc item if the trait was local, because we were looking for a small span only for the generics, which we don't have for foreign traits. We now use `def_span` for the item, so we at least provide some context, even if its span is too wide.
```
error[E0195]: lifetime parameters or bounds on type `IntoIter` do not match the trait declaration
--> tests/ui/lifetimes/missing-lifetime-in-assoc-type-4.rs:7:18
|
7 | type IntoIter<'a> = std::collections::btree_map::Values<'a, i32, T>;
| ^^^^ lifetimes do not match type in trait
|
::: /home/gh-estebank/rust/library/core/src/iter/traits/collect.rs:292:5
|
292 | type IntoIter: Iterator<Item = Self::Item>;
| ------------------------------------------ lifetimes in impl do not match this type in trait
```
Previously, when an `impl Trait` captured multiple higher-ranked
lifetimes from an outer `impl Trait`, the compiler would emit a
separate error for each captured lifetime. This resulted in verbose
and confusing diagnostics, especially in edition 2024 where implicit
captures caused duplicate errors.
This commit introduces error accumulation that collects all capture
spans and lifetime declaration spans, then emits a single consolidated
diagnostic using MultiSpan. The new error shows all captured lifetimes
with visual indicators and lists all declarations in a single note.
Having multiple relaxed bounds like `?Sized + ?Iterator` is actually *fine*.
We actually want to reject *duplicate* relaxed bounds like `?Sized + ?Sized`
because these most certainly represent a user error.
Note that this doesn't mean that we accept more code because a bound like
`?Iterator` is still invalid as it's not relaxing a *default* trait and
the only way to define / use more default bounds is under the experimental
and internal feature `more_maybe_bounds` plus `lang_items` plus unstable
flag `-Zexperimental-default-bounds` (historical context: for the longest
time, bounds like `?Iterator` were actually allowed and lead to a hard
warning).
Ultimately, this simply *reframes* the diagnostic. The scope of
`more_maybe_bounds` / `-Zexperimental-default-bounds` remains unchanged
as well.
variadic functions: remove list of supported ABIs from error
I think this list is problematic for multiple reasons:
- It is bound to go out-of-date as it is in a very different place from where we actually define which functions support varagrs (`fn supports_varargs`).
- Many of the ABIs we list only work on some targets; it makes no sense to mention "aapcs" as a possible ABI when building for x86_64. (This led to a lot of confusion in https://github.com/rust-lang/rust/issues/110505 where the author thought they should use "cdecl" and then were promptly told that "cdecl" is not a legal ABI on their target.)
- Typically, when the programmer wrote `extern "foobar"`, it is because they need the "foobar" ABI. It is of little use to tell them that there are other ABIs with which varargs would work.
Cc ``@workingjubilee``
It bugs me when variables of type `Ident` are called `name`. It leads to
silly things like `name.name`. `Ident` variables should be called
`ident`, and `name` should be used for variables of type `Symbol`.
This commit improves things by by doing `s/name/ident/` on a bunch of
`Ident` variables. Not all of them, but a decent chunk.
Fixes#139082.
Emits an error when `Self` is found in the projection bounds of a trait
object. In type aliases, `Self` has no meaning, so `type A = &'static
dyn B` where `trait B = Fn() -> Self` will expands to `type A = &'static
Fn() -> Self` which is illegal, causing the region solver to bail out
when hitting the uninferred Self.
Bug: #139082
Signed-off-by: xtex <xtexchooser@duck.com>
Try to point of macro expansion from resolver and method errors if it involves macro var
In the case that a macro caller passes an identifier into a macro generating a path or method expression, point out that identifier in the context of the *macro* so it's a bit more clear how the macro is involved in causing the error.
r? ``````````@estebank`````````` or reassign
Rollup of 8 pull requests
Successful merges:
- #134981 ( Explain that in paths generics can't be set on both the enum and the variant)
- #136698 (Replace i686-unknown-redox target with i586-unknown-redox)
- #136767 (improve host/cross target checking)
- #136829 ([rustdoc] Move line numbers into the `<code>` directly)
- #136875 (Rustc dev guide subtree update)
- #136900 (compiler: replace `ExternAbi::name` calls with formatters)
- #136913 (Put kobzol back on review rotation)
- #136915 (documentation fix: `f16` and `f128` are not double-precision)
r? `@ghost`
`@rustbot` modify labels: rollup
Jana Dönszelmann