Lint dead code in closures and generators
Fixes#108296
I think this might be a potentially breaking change, but restores the behaviour of pre-1.64.
`@rustbot` label +A-lint
Don't delay `ReError` bug during lexical region resolve
Lexical region resolution returns a list of `RegionResolutionError` which don't necessarily correspond to diagnostics being emitted. The compiler may, validly, throw away these resolution errors and do something else. Therefore it's not valid to use `ReError` during lifetime resolution, since we may actually be on a totally fine compilation path.
For example, the `implied_bounds_entailment` lint runs region resolution twice, and only emits an error if it fails both times. If we delay a bug and create a `ReError` during this first run, then we will ICE.
Fixes#108170
----
Side-note: this is conceptually equivalent to how we can't necessarily delay bugs or create `ty::Error` during trait solving/fulfillment, since the compiler is allowed to throw away these fulfillment errors to do other things. It's only once we actually emit an error (`report_region_errors` / `report_fulfillment_errors`)
Fix overlapping spans in removing extra arguments
Fixes#108225
Each span is already extended to include the previous comma, so extending to the *next* comma is unecessary and causes an ICE with assertions on.
``@rustbot`` label +A-diagnostics
Convert a hard-warning about named static lifetimes into lint "unused_lifetimes"
Fixes https://github.com/rust-lang/rust/issues/96956.
Some changes are ported from https://github.com/rust-lang/rust/pull/98079, thanks to jeremydavis519.
r? `@estebank` `@petrochenkov`
Any feedback is appreciated!
## Actions
- [x] resolve conflicts
- [x] fix build
- [x] address review comments in last pr
- [x] update tests
Define the `named_static_lifetimes` lint
This lint will replace the existing hard-warning.
Replace the named static lifetime hard-warning with the new lint
Update the UI tests for the `named_static_lifetimes` lint
Remove the direct dependency on `rustc_lint_defs`
fix build
Signed-off-by: Zhi Qi <qizhi@pingcap.com>
use "UNUSED_LIFETIMES" instead
Signed-off-by: Zhi Qi <qizhi@pingcap.com>
update 1 test and fix typo
Signed-off-by: Zhi Qi <qizhi@pingcap.com>
update tests
Signed-off-by: Zhi Qi <qizhi@pingcap.com>
fix tests: add extra blank line
Signed-off-by: Zhi Qi <qizhi@pingcap.com>
Use DefKind to give more item kind information during BindingObligation note
The current label says "required by a bound in this". When I see that label, my immediate impression is "this... **what**?". It feels like it was cut short.
Alternative to this would be saying "in this item", but adding the item kind is strictly more informational and adds very little overhead to the existing error presentation.
Make hidden type registration opt-in, so that each site can be reviewed on its own and we have the right defaults for trait solvers
r? `@lcnr`
pulled out of https://github.com/rust-lang/rust/pull/107891 as it is the uncontroversial part
Move `Fn*` traits malformedness protections to typeck
I found it strange that we were doing a custom well-formedness check just for the `Fn*` traits' `call_*` fn items. My understanding from the git history is that this is just to avoid ICEs later on in typeck.
Well, that well-formedness check isn't even implemented correctly for `FnOnce::call_once`, or `FnMut::call_mut` for that matter. Instead, this PR just makes the typeck checks more robust, and leaves it up to the call-site to report errors when lang items are implemented in funny ways.
This coincidentally fixes another ICE where a the `Add` lang item is implemented with a `add` item that's a const instead of a method.
Add a test for default trait method with RPITITs
This didn't work in #107013, but now that #108203 has landed, let's make sure we don't regress it.
r? types
Name placeholder in some region errors
Also don't print `ReVar` or `ReLateBound` as debug... these error messages are super uncommon anyways, but in the case they do trigger, let's be slightly more helpful.
lint: don't suggest MaybeUninit::assume_init for uninhabited types
Creating a zeroed uninhabited type such as `!` or an empty enum with `mem::zeroed()` (or transmuting `()` to `!`) currently triggers this lint:
```rs
warning: the type `!` does not permit zero-initialization
--> test.rs:5:23
|
5 | let _val: ! = mem::zeroed();
| ^^^^^^^^^^^^^
| |
| this code causes undefined behavior when executed
| help: use `MaybeUninit<T>` instead, and only call `assume_init` after initialization is done
|
= note: the `!` type has no valid value
```
The `MaybeUninit` suggestion in the help message seems confusing/useless for uninhabited types, as such a type cannot be fully initialized in the first place (as the note implies).
This PR limits this help message to inhabited types which can be initialized
Miri: basic dyn* support
As usual I am very unsure about the dynamic dispatch stuff, but it passes even the `Pin<&mut dyn* Trait>` test so that is something.
TBH I think it was a mistake to make `dyn Trait` and `dyn* Trait` part of the same `TyKind` variant. Almost everywhere in Miri this lead to the wrong default behavior, resulting in strange ICEs instead of nice "unimplemented" messages. The two types describe pretty different runtime data layout after all.
Strangely I did not need to do the equivalent of [this diff](https://github.com/rust-lang/rust/pull/106532#discussion_r1087095963) in Miri. Maybe that is because the unsizing logic matches on `ty::Dynamic(.., ty::Dyn)` already? In `unsized_info` I don't think the `target_dyn_kind` can be `DynStar`, since then it wouldn't be unsized!
r? `@oli-obk` Cc `@eholk` (dyn-star) https://github.com/rust-lang/rust/issues/102425
Refine error span for trait error into borrowed expression
Extends the error span refinement in #106477 to drill into borrowed expressions just like tuples/struct/enum literals. For example,
```rs
trait Fancy {}
trait Good {}
impl <'a, T> Fancy for &'a T where T: Good {}
impl <S> Good for Option<S> where S: Iterator {}
fn want_fancy<F>(f: F) where F: Fancy {}
fn example() {
want_fancy(&Some(5));
// (BEFORE) ^^^^^^^^ `{integer}` is not an iterator
// (AFTER) ^ `{integer}` is not an iterator
}
```
Existing heuristics try to find the right part of the expression to "point at"; current heuristics look at e.g. struct constructors and tuples. This PR adds a new check for borrowed expressions when looking into a borrowed type.
Use restricted Damerau-Levenshtein distance for diagnostics
This replaces the existing Levenshtein algorithm with the Damerau-Levenshtein algorithm. This means that "ab" to "ba" is one change (a transposition) instead of two (a deletion and insertion). More specifically, this is a _restricted_ implementation, in that "ca" to "abc" cannot be performed as "ca" → "ac" → "abc", as there is an insertion in the middle of a transposition. I believe that errors like that are sufficiently rare that it's not worth taking into account.
This was first brought up [on IRLO](https://internals.rust-lang.org/t/18227) when it was noticed that the diagnostic for `prinltn!` (transposed L and T) was `print!` and not `println!`. Only a single existing UI test was effected, with the result being an objective improvement.
~~I have left the method name and various other references to the Levenshtein algorithm untouched, as the exact manner in which the edit distance is calculated should not be relevant to the caller.~~
r? ``@estebank``
``@rustbot`` label +A-diagnostics +C-enhancement
create dummy placeholder crate to prevent compiler from panicing
This PR is to address the panic found in https://github.com/rust-lang/rust/issues/105700.
There are 2 separate things going on with this panic.
First the code could not generate a dummy response for crate fragment types when it hits the recursion limit.
This PR adds the method to the trait implementation for `DymmyResult` to be able to create a dummy crate node.
This stops the panic from happening.
The second thing that is not addressed (and maybe does not need addressing? 🤷🏻)
is that when you have multiple attributes it ends up treating attributes that follow another as being the result of expanding the former (maybe there is a better way to say that). So you end up hitting the recursion limit. Even though you would think there is no expansion happening here.
If you did not hit the recursion limit the compiler would output that `invalid_attribute` does not exists. But it currently exits before the resolution step when the recursion limit is reached here.
Type-directed probing for inherent associated types
When probing for inherent associated types (IATs), equate the Self-type found in the projection with the Self-type of the relevant inherent impl blocks and check if all predicates are satisfied.
Previously, we didn't look at the Self-type or at the bounds and just picked the first inherent impl block containing an associated type with the name we were searching for which is obviously incorrect.
Regarding the implementation, I basically copied what we do during method probing (`assemble_inherent_impl_probe`, `consider_probe`). Unfortunately, I had to duplicate a lot of the diagnostic code found in `rustc_hir_typeck::method::suggest` which we don't have access to in `rustc_hir_analysis`. Not sure if there is a simple way to unify the error handling. Note that in the future, `rustc_hir_analysis::astconv` might not actually be the place where we resolve inherent associated types (see https://github.com/rust-lang/rust/pull/103621#issuecomment-1304309565) but `rustc_hir_typeck` (?) in which case the duplication may naturally just disappear. While inherent associated *constants* are currently resolved during "method" probing, I did not find a straightforward way to incorporate IAT lookup into it as types and values (functions & constants) are two separate entities for which distinct code paths are taken.
Fixes#104251 (incl. https://github.com/rust-lang/rust/issues/104251#issuecomment-1338501171).
Fixes#105305.
Fixes#107468.
`@rustbot` label T-types F-inherent_associated_types
r? types
