Fix `option_if_let_else`
fixes: #5822fixes: #6737fixes: #7567
The inference from #6137 still exists so I'm not sure if this should be moved from the nursery. Before doing that though I'd almost want to see this split into two lints. One suggesting `map_or` and the other suggesting `map_or_else`.
`map_or_else` tends to have longer expressions for both branches so it doesn't end up much shorter than a match expression in practice. It also seems most people find it harder to read. `map_or` at least has the terseness benefit of being on one line most of the time, especially when the `None` branch is just a literal or path expression.
changelog: `break` and `continue` statments local to the would-be closure are allowed in `option_if_let_else`
changelog: don't lint in const contexts in `option_if_let_else`
changelog: don't lint when yield expressions are used in `option_if_let_else`
changelog: don't lint when the captures made by the would-be closure conflict with the other branch in `option_if_let_else`
changelog: don't lint when a field of a local is used when the type could be pontentially moved from in `option_if_let_else`
changelog: in some cases, don't lint when scrutinee expression conflicts with the captures of the would-be closure in `option_if_let_else`
Add module_style lint to style
changelog: Add new [`module_style`] style lint
This is a configurable (no mod file/mod file) lint that determines if `mod.rs` is used consistently or if `mod.rs` is never used (using the new mod layout).
Don't report function calls as unnecessary operation if used in array index
Attempts to fix: #7412
changelog: Don't report function calls used in indexing as unnecessary operation. [`unnecessary_operation`]
Add tests for disallowed_mod in ui-cargo test section
Use correct algorithm to determine if mod.rs is missing
Move to two lints and remove config option
Switch lint names so they read "warn on ..."
Emit the same help info for self_named_mod_file warnings
Bail when both lints are Allow
Reword help message for both module_style lints
Add new lint `negative_feature_names` and `redundant_feature_names`
Add new lint [`negative_feature_names`] to detect feature names with prefixes `no-` or `not-` and new lint [`redundant_feature_names`] to detect feature names with prefixes `use-`, `with-` or suffix `-support`
changelog: Add new lint [`negative_feature_names`] and [`redundant_feature_names`]
New lint `manual_split_once`
This is a WIP because it still needs to recognize more patterns. Currently handles:
```rust
s.splitn(2, ' ').next();
s.splitn(2, ' ').nth(0)
s.splitn(2, ' ').nth(1);
s.splitn(2, ' ').skip(0).next();
s.splitn(2, ' ').skip(1).next();
s.splitn(2, ' ').next_tuple(); // from itertools
// as well as `unwrap()` and `?` forms
```
Still to do:
```rust
let mut iter = s.splitn(2, ' ');
(iter.next().unwrap(), iter.next()?)
let mut iter = s.splitn(2, ' ');
let key = iter.next().unwrap();
let value = iter.next()?;
```
Suggestions on other patterns to check for would be useful. I've done a search on github for uses of `splitn`. Still have yet to actually look through the results.
There's also the question of whether the lint shouold trigger on all uses of `splitn` with two values, or only on recognized usages. The former could have false positives where it couldn't be replaced, but I'm not sure how common that would be.
changelog: Add lint `manual_split_once`
* `break` and `continue` statments local to the would-be closure are allowed
* don't lint in const contexts
* don't lint when yield expressions are used
* don't lint when the captures made by the would-be closure conflict with the other branch
* don't lint when a field of a local is used when the type could be pontentially moved from
* in some cases, don't lint when scrutinee expression conflicts with the captures of the would-be closure
Uplift the invalid_atomic_ordering lint from clippy to rustc
This is mostly just a rebase of https://github.com/rust-lang/rust/pull/79654; I've copy/pasted the text from that PR below.
r? `@lcnr` since you reviewed the last one, but feel free to reassign.
---
This is an implementation of https://github.com/rust-lang/compiler-team/issues/390.
As mentioned, in general this turns an unconditional runtime panic into a (compile time) lint failure. It has no false positives, and the only false negatives I'm aware of are if `Ordering` isn't specified directly and is comes from an argument/constant/whatever.
As a result of it having no false positives, and the alternative always being strictly wrong, it's on as deny by default. This seems right.
In the [zulip stream](https://rust-lang.zulipchat.com/#narrow/stream/233931-t-compiler.2Fmajor-changes/topic/Uplift.20the.20.60invalid_atomic_ordering.60.20lint.20from.20clippy/near/218483957) `@joshtriplett` suggested that lang team should FCP this before landing it. Perhaps libs team cares too?
---
Some notes on the code for reviewers / others below
## Changes from clippy
The code is changed from [the implementation in clippy](68cf94f6a6/clippy_lints/src/atomic_ordering.rs) in the following ways:
1. Uses `Symbols` and `rustc_diagnostic_item`s instead of string literals.
- It's possible I should have just invoked Symbol::intern for some of these instead? Seems better to use symbol, but it did require adding several.
2. The functions are moved to static methods inside the lint struct, as a way to namespace them.
- There's a lot of other code in that file — which I picked as the location for this lint because `@jyn514` told me that seemed reasonable.
3. Supports unstable AtomicU128/AtomicI128.
- I did this because it was almost easier to support them than not — not supporting them would have (ideally) required finding a way not to give them a `rustc_diagnostic_item`, which would have complicated an already big macro.
- These don't have tests since I wasn't sure if/how I should make tests conditional on whether or not the target has the atomic... This is to a certain extent an issue of 64bit atomics too, but 128-bit atomics are much less common. Regardless, the existing tests should be *more* than thorough enough here.
4. Minor changes like:
- grammar tweaks ("loads cannot have `Release` **and** `AcqRel` ordering" => "loads cannot have `Release` **or** `AcqRel` ordering")
- function renames (`match_ordering_def_path` => `matches_ordering_def_path`),
- avoiding clippy-specific helper methods that don't exist in rustc_lint and didn't seem worth adding for this case (for example `cx.struct_span_lint` vs clippy's `span_lint_and_help` helper).
## Potential issues
(This is just about the code in this PR, not conceptual issues with the lint or anything)
1. I'm not sure if I should have used a diagnostic item for `Ordering` and its variants (I couldn't figure out how really, so if I should do this some pointers would be appreciated).
- It seems possible that failing to do this might possibly mean there are more cases this lint would miss, but I don't really know how `match_def_path` works and if it has any pitfalls like that, so maybe not.
2. I *think* I deprecated the lint in clippy (CC `@flip1995` who asked to be notified about clippy changes in the future in [this comment](https://github.com/rust-lang/rust/pull/75671#issuecomment-718731659)) but I'm not sure if I need to do anything else there.
- I'm kind of hoping CI will catch if I missed anything, since `x.py test src/tools/clippy` fails with a lot of errors with and without my changes (and is probably a nonsense command regardless). Running `cargo test` from src/tools/clippy also fails with unrelated errors that seem like refactorings that didnt update clippy? So, honestly no clue.
3. I wasn't sure if the description/example I gave good. Hopefully it is. The example is less thorough than the one from clippy here: https://rust-lang.github.io/rust-clippy/master/index.html#invalid_atomic_ordering. Let me know if/how I should change it if it needs changing.
4. It pulls in the `if_chain` crate. This crate was already used in clippy, and seems like it's used elsewhere in rustc, but I'm willing to rewrite it to not use this if needed (I'd prefer not to, all things being equal).
- Deprecate clippy::invalid_atomic_ordering
- Use rustc_diagnostic_item for the orderings in the invalid_atomic_ordering lint
- Reduce code duplication
- Give up on making enum variants diagnostic items and just look for
`Ordering` instead
I ran into tons of trouble with this because apparently the change to
store HIR attrs in a side table also gave the DefIds of the
constructor instead of the variant itself. So I had to change
`matches_ordering` to also check the grandparent of the defid as well.
- Rename `atomic_ordering_x` symbols to just the name of the variant
- Fix typos in checks - there were a few places that said "may not be
Release" in the diagnostic but actually checked for SeqCst in the lint.
- Make constant items const
- Use fewer diagnostic items
- Only look at arguments after making sure the method matches
This prevents an ICE when there aren't enough arguments.
- Ignore trait methods
- Only check Ctors instead of going through `qpath_res`
The functions take values, so this couldn't ever be anything else.
- Add if_chain to allowed dependencies
- Fix grammar
- Remove unnecessary allow
Manual map 7413
fixes: #7413
This only fixes the specific problem from #7413, not the general case. The full fix requires interacting with the borrow checker to determine the lifetime of all the borrows made in the function. I'll open an issue about it later.
changelog: Don't suggest using `map` when the option is borrowed in the match, and also consumed in the arm.
changelog: Locals declared within the would-be closure will not prevent the closure from being suggested in `manual_map` and `map_entry`
