Rescope temp lifetime in if-let into IfElse with migration lint
Tracking issue #124085
This PR shortens the temporary lifetime to cover only the pattern matching and consequent branch of a `if let`.
At the expression location, means that the lifetime is shortened from previously the deepest enclosing block or statement in Edition 2021. This warrants an Edition change.
Coming with the Edition change, this patch also implements an edition lint to warn about the change and a safe rewrite suggestion to preserve the 2021 semantics in most cases.
Related to #103108.
Related crater runs: https://github.com/rust-lang/rust/pull/129466.
Fix `clippy::useless_conversion`
Self-explanatory. Probably the last clippy change I'll actually put up since this is the only other one I've actually seen in the wild.
Simplify some nested `if` statements
Applies some but not all instances of `clippy::collapsible_if`. Some ended up looking worse afterwards, though, so I left those out. Also applies instances of `clippy::collapsible_else_if`
Review with whitespace disabled please.
Correctly handle stability of `#[diagnostic]` attributes
This commit changes the way we treat the stability of attributes in the
`#[diagnostic]` namespace. Instead of relaying on ad-hoc checks to
ensure at call side that a certain attribute is really usable at that
location it centralises the logic to one place. For diagnostic
attributes comming from other crates it just skips serializing
attributes that are not stable and that do not have the corresponding
feature enabled. For attributes from the current crate we can just use
the feature information provided by `TyCtx`.
r? `@compiler-errors`
Arbitrary self types v2: pointers feature gate.
The main `arbitrary_self_types` feature gate will shortly be reused for a new version of arbitrary self types which we are amending per [this RFC](https://github.com/rust-lang/rfcs/blob/master/text/3519-arbitrary-self-types-v2.md). The main amendments are:
* _do_ support `self` types which can't safely implement `Deref`
* do _not_ support generic `self` types
* do _not_ support raw pointers as `self` types.
This PR relates to the last of those bullet points: this strips pointer support from the current `arbitrary_self_types` feature. We expect this to cause some amount of breakage for crates using this unstable feature to allow raw pointer self types. If that's the case, we want to know about it, and we want crate authors to know of the upcoming changes.
For now, this can be resolved by adding the new
`arbitrary_self_types_pointers` feature to such crates. If we determine that use of raw pointers as self types is common, then we may maintain that as an unstable feature even if we come to stabilize the rest of the `arbitrary_self_types` support in future. If we don't hear that this PR is causing breakage, then perhaps we don't need it at all, even behind an unstable feature gate.
[Tracking issue](https://github.com/rust-lang/rust/issues/44874)
This is [step 4 of the plan outlined here](https://github.com/rust-lang/rust/issues/44874#issuecomment-2122179688)
Suggest `impl Trait` for References to Bare Trait in Function Header
Fixes#125139
This PR suggests `impl Trait` when `&Trait` is found as a function parameter type or return type. This makes use of existing diagnostics by adding `peel_refs()` when checking for type equality.
Additionaly, it makes a few other improvements:
1. Checks if functions inside impl blocks have bare trait in their headers.
2. Introduces a trait `NextLifetimeParamName` similar to the existing `NextTypeParamName` for suggesting a lifetime name. Also, abstracts out the common logic between the two trait impls.
### Related Issues
I ran into a bunch of related diagnostic issues but couldn't fix them within the scope of this PR. So, I have created the following issues:
1. [Misleading Suggestion when Returning a Reference to a Bare Trait from a Function](https://github.com/rust-lang/rust/issues/127689)
2. [Verbose Error When a Function Takes a Bare Trait as Parameter](https://github.com/rust-lang/rust/issues/127690)
3. [Incorrect Suggestion when Returning a Bare Trait from a Function](https://github.com/rust-lang/rust/issues/127691)
r? ```@estebank``` since you implemented #119148
Remove `#[macro_use] extern crate tracing`, round 4
Because explicit importing of macros via use items is nicer (more standard and readable) than implicit importing via #[macro_use]. Continuing the work from #124511, #124914, and #125434. After this PR no `rustc_*` crates use `#[macro_use] extern crate tracing` except for `rustc_codegen_gcc` which is a special case and I will do separately.
r? ```@jieyouxu```
Get rid of `predicates_defined_on`
This is the uncontroversial part of #129532. This simply inlines the `predicates_defined_on` into into `predicates_of`. Nothing should change here logically.
Stop storing a special inner body for the coroutine by-move body for async closures
...and instead, just synthesize an item which is treated mostly normally by the MIR pipeline.
This PR does a few things:
* We synthesize a new `DefId` for the by-move body of a closure, which has its `mir_built` fed with the output of the `ByMoveBody` MIR transformation, and some other relevant queries.
* This has the `DefKind::ByMoveBody`, which we use to distinguish it from "real" bodies (that come from HIR) which need to be borrowck'd. Introduce `TyCtxt::is_synthetic_mir` to skip over `mir_borrowck` which is called by `mir_promoted`; borrowck isn't really possible to make work ATM since it heavily relies being called on a body generated from HIR, and is redundant by the construction of the by-move-body.
* Remove the special `PassManager` hacks for handling the inner `by_move_body` stored within the coroutine's mir body. Instead, this body is fed like a regular MIR body, so it's goes through all of the `tcx.*_mir` stages normally (build -> promoted -> ...etc... -> optimized) ✨.
* Remove the `InstanceKind::ByMoveBody` shim, since now we have a "regular" def id, we can just use `InstanceKind::Item`. This also allows us to remove the corresponding hacks from codegen, such as in `fn_sig_for_fn_abi` ✨.
Notable remarks:
* ~~I know it's kind of weird to be using `DefKind::Closure` here, since it's not a distinct closure but just a new MIR body. I don't believe it really matters, but I could also use a different `DefKind`... maybe one that we could use for synthetic MIR bodies in general?~~ edit: We're doing this now.
The main `arbitrary_self_types` feature gate will shortly be reused for
a new version of arbitrary self types which we are amending per [this
RFC](https://github.com/rust-lang/rfcs/blob/master/text/3519-arbitrary-self-types-v2.md).
The main amendments are:
* _do_ support `self` types which can't safely implement `Deref`
* do _not_ support generic `self` types
* do _not_ support raw pointers as `self` types.
This PR relates to the last of those bullet points: this strips pointer
support from the current `arbitrary_self_types` feature.
We expect this to cause some amount of breakage for crates using this
unstable feature to allow raw pointer self types. If that's the case, we
want to know about it, and we want crate authors to know of the upcoming
changes.
For now, this can be resolved by adding the new
`arbitrary_self_types_pointers` feature to such crates. If we determine
that use of raw pointers as self types is common, then we may maintain
that as an unstable feature even if we come to stabilize the rest of the
`arbitrary_self_types` support in future. If we don't hear that this PR
is causing breakage, then perhaps we don't need it at all, even behind
an unstable feature gate.
[Tracking issue](https://github.com/rust-lang/rust/issues/44874)
This is [step 4 of the plan outlined here](https://github.com/rust-lang/rust/issues/44874#issuecomment-2122179688)
Remove redundant flags from `lower_ty_common` that can be inferred from the HIR
...and then get rid of `lower_ty_common`.
r? ``@fmease`` or re-roll if you're busy!
Print the generic parameter along with the variance in dumps.
This allows to make sure we are testing what we think we are testing.
While the tests are correct, I discovered that opaque duplicated args are in the reverse declaration order.
