Rollup of 7 pull requests
Successful merges:
- #86747 (Improve wording of the `drop_bounds` lint)
- #87166 (Show discriminant before overflow in diagnostic for duplicate values.)
- #88077 (Generate an iOS LLVM target with a specific version)
- #88164 (PassWrapper: adapt for LLVM 14 changes)
- #88211 (cleanup: `Span::new` -> `Span::with_lo`)
- #88229 (Suggest importing the right kind of macro.)
- #88238 (Stop tracking namespace in used_imports.)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Improve wording of the `drop_bounds` lint
This PR addresses #86653. The issue is sort of a false positive of the `drop_bounds` lint, but I would argue that the best solution for #86653 is simply a rewording of the warning message and lint description, because even if the lint is _technically_ wrong, it still forces the programmer to think about what they are doing, and they can always use `#[allow(drop_bounds)]` if they think that they really need the `Drop` bound.
There are two issues with the current warning message and lint description:
- First, it says that `Drop` bounds are "useless", which is technically incorrect because they actually do have the effect of allowing you e.g. to call methods that also have a `Drop` bound on their generic arguments for some reason. I have changed the wording to emphasize not that the bound is "useless", but that it is most likely not what was intended.
- Second, it claims that `std::mem::needs_drop` detects whether a type has a destructor. But I think this is also technically wrong: The `Drop` bound says whether the type has a destructor or not, whereas `std::mem::needs_drop` also takes nested types with destructors into account, even if the top-level type does not itself have one (although I'm not 100% sure about the exact terminology here, i.e. whether the "drop glue" of the top-level type counts as a destructor or not).
cc `@jonhoo,` does this solve the issue for you?
r? `@GuillaumeGomez`
canonicalize consts before calling try_unify_abstract_consts query
Fixes#88022Fixes#86953Fixes#77708Fixes#82034Fixes#85031
these ICEs were all caused by calling the `try_unify_abstract_consts` query with inference vars in substs
r? `@lcnr`
marker_traits: require `EvaluatedToOk` during winnowing
closes#84955, while it doesn't really fix it in a way that makes me happy it should prevent the issue for now and this
test can't be reproduced anyways, so it doesn't make much sense to keep it open.
fixes#84917 as only one of the impls depends on regions, so we now drop the ambiguous one instead of the correct one.
cc https://rust-lang.zulipchat.com/#narrow/stream/144729-wg-traits/topic/winnowing.20soundly/near/247899832
r? `@nikomatsakis`
Test tait use in a fn type
r? `@oli-obk`
I thought this was going to work but doesn't, quickly checked with Niko and he told me that we ruled this out for now. I'm not exactly sure why and how but here we have a test with a FIXME :)
Related to #86727
Trait upcasting coercion (part 3)
By using separate candidates for each possible choice, this fixes type-checking issues in previous commits.
r? `@nikomatsakis`
Give precedence to `html_root_url` over `--extern-html-root-url` by default, but add a way to opt-in to the previous behavior
## What is an HTML root url?
It tells rustdoc where it should link when documentation for a crate is
not available locally; for example, when a crate is a dependency of a
crate documented with `cargo doc --no-deps`.
## What is the difference between `html_root_url` and `--extern-html-root-url`?
Both of these tell rustdoc what the HTML root should be set to.
`doc(html_root_url)` is set by the crate author, while
`--extern-html-root-url` is set by the person documenting the crate.
These are often different. For example, docs.rs uses
`--extern-html-root-url https://docs.rs/crate-name/version` to ensure
all crates have documentation, even if `html_root_url` is not set.
Conversely, crates such as Rocket set `doc(html_root_url =
"https://api.rocket.rs")`, because they prefer users to view the
documentation on their own site.
Crates also set `html_root_url` to ensure they have
documentation when building locally when offline. This is unfortunate to
require, because it's more work from the library author. It also makes
it impossible to distinguish between crates that want to be viewed on a
different site (e.g. Rocket) and crates that just want documentation to
be visible offline at all (e.g. Tokio). I have authored a separate
change to the API guidelines to no longer recommend doing this:
rust-lang/api-guidelines#230.
## Why change the default?
In the past, docs.rs has been the main user of `--extern-html-root-url`.
However, it's useful for other projects as well. In particular, Cargo
wants to pass it by default when running `--no-deps`
(rust-lang/cargo#8296).
Unfortunately, for these other use cases, the priority order is
inverted. They want to give *precedence* to the URL the crate picks, and
only fall back to the `--extern-html-root` if no `html_root_url` is
present. That allows passing `--extern-html-root` unconditionally,
without having to parse the source code to see what attributes are
present.
For docs.rs, however, we still want to keep the old behavior, so that
all links on docs.rs stay on the site.
Instead of updating global state to mark attributes as used,
we now explicitly emit a warning when an attribute is used in
an unsupported position. As a side effect, we are to emit more
detailed warning messages (instead of just a generic "unused" message).
`Session.check_name` is removed, since its only purpose was to mark
the attribute as used. All of the callers are modified to use
`Attribute.has_name`
Additionally, `AttributeType::AssumedUsed` is removed - an 'assumed
used' attribute is implemented by simply not performing any checks
in `CheckAttrVisitor` for a particular attribute.
We no longer emit unused attribute warnings for the `#[rustc_dummy]`
attribute - it's an internal attribute used for tests, so it doesn't
mark sense to treat it as 'unused'.
With this commit, a large source of global untracked state is removed.
Force warn improvements
As part of stablization of the `--force-warn` option (#86516) I've made the following changes:
* Error when the `warnings` lint group is based to the `--force-warn` option
* Tests have been updated to make it easier to understand the semantics of `--force-warn`
r? `@nikomatsakis`
Upgrade to LLVM 13
Work in progress update to LLVM 13. Main changes:
* InlineAsm diagnostics reported using SrcMgr diagnostic kind are now handled. Previously these used a separate diag handler.
* Codegen tests are updated for additional attributes.
* Some data layouts have changed.
* Switch `#[used]` attribute from `llvm.used` to `llvm.compiler.used` to avoid SHF_GNU_RETAIN flag introduced in https://reviews.llvm.org/D97448, which appears to trigger a bug in older versions of gold.
* Set `LLVM_INCLUDE_TESTS=OFF` to avoid Python 3.6 requirement.
Upstream issues:
* ~~https://bugs.llvm.org/show_bug.cgi?id=51210 (InlineAsm diagnostic reporting for module asm)~~ Fixed by 1558bb80c0.
* ~~https://bugs.llvm.org/show_bug.cgi?id=51476 (Miscompile on AArch64 due to incorrect comparison elimination)~~ Fixed by 81b106584f.
* https://bugs.llvm.org/show_bug.cgi?id=51207 (Can't set custom section flags anymore). Problematic change reverted in our fork, https://reviews.llvm.org/D107216 posted for upstream revert.
* https://bugs.llvm.org/show_bug.cgi?id=51211 (Regression in codegen for #83623). This is an optimization regression that we may likely have to eat for this release. The fix for #83623 was based on an incorrect premise, and this needs to be properly addressed in the MergeICmps pass.
The [compile-time impact](https://perf.rust-lang.org/compare.html?start=ef9549b6c0efb7525c9b012148689c8d070f9bc0&end=0983094463497eec22d550dad25576a894687002) is mixed, but quite positive as LLVM upgrades go.
The LLVM 13 final release is scheduled for Sep 21st. The current nightly is scheduled for stable release on Oct 21st.
r? `@ghost`
