new lints around`#[must_use]`
changelog: Add `must_use_candidate` lint, add `must-use-unit` lint, add `double_must_use` lint
The first one checks if an public function or method has no mutable argument and mutates no non-local data and lints if it has no `#[must_use]` attribute. It will skip inner functions, because those are usually highly local and the attribute doesn't have as much benefit there.
The second lints `#[must_use]` attributes on functions and methods that return unit. Those attributes are likely a remnant from a refactoring that removed the return value.
The last one lints for `#[must_use]` attributrs without text on functions that return a type which is already marked `#[must_use]`. This has no auto-suggestion, because while it would be easy to do, there may be value in writing a detailed text for the attribute instead.
This fixes#4526
`must_use_unit` lints unit-returning functions with a `#[must_use]`
attribute, suggesting to remove it.
`double_must_use` lints functions with a plain `#[must_use]`
attribute, but which return a type which is already `#[must_use]`,
so the attribute has no benefit.
`must_use_candidate` is a pedantic lint that lints functions and
methods that return some non-unit type that is not already
`#[must_use]` and suggests to add the annotation.
PR template might not be stripped by contributors
cc d97fbdbb42
So I think it would be better to make the template visible.
Also I renamed the template with extension `.md`.
changelog: none
Lints when, on the RHS of a BinOp, there is a UnOp without a space
before the operator but with a space after (e.g. foo >- 1).
Signed-off-by: Nikos Filippakis <nikolaos.filippakis@cern.ch>
Add assert message to suggestion in lint assertions_on_constants
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- [x] suggest replacing `assert!(false, "msg")` with `panic!("msg")`
- [x] extend to allow ~~variables~~ any expression for `"msg"`
- ~~suggest replacing `assert!(false, "msg {}", "arg")` with `panic!("msg {}", "arg")`~~
changelog: add assert message to suggestion in lint assertions_on_constants
Work towards fixing: #3575
Add suggestion for mul_add
Issue #4001: Whenever `a*b+c` is found where `a`,`b`, and `c` are floats, a lint is suggested saying to use `a.mul_add(b, c)`. Using `mul_add` may give a performance boost depending on the target architecture and also has higher numerical accuracy as there is no round off when doing `a*b`.
changelog: New lint: `manual_mul_add`
Fix typo in inherent_to_string documentation
A simple typo fix in `inherent_to_string` and `inherent_to_string_shadow_display` documentation
changelog: none
account for doc visibility
This fixes#4608.
Also I noticed that the lint failed to look at trait and impl items. There's a small bit of fallout in the code, too, but not enough to warrant its own commit.
changelog: check docs of trait items and impl items, also make `missing_safety_doc` account for visibility
Add check for assert_eq macros to unit_cmp lint
changelog: Add check for unit comparisons through `assert_eq!`, `debug_assert_eq!`, `assert_ne!` and `debug_assert_ne!` macros to unit_cmp lint.
fixes#4481
Use windows-sdk-10.1 to avoid installation failure
This fixes installation failure on Windows on Travis but we need to fix rustfmt issue first to pass the CI completely.
changelog: none
Rollup of 2 pull requests
Successful merges:
- #4509 (Fix false-positive of redundant_clone and move to clippy::perf)
- #4614 (Allow casts from the result of `abs` to unsigned)
Failed merges:
changelog: none
r? @ghost
Fix false-positive of redundant_clone and move to clippy::perf
This PR introduces dataflow analysis to `redundant_clone` lint to filter out borrowed variables, which had been incorrectly detected.
Depends on https://github.com/rust-lang/rust/pull/64207.
changelog: Moved `redundant_clone` lint to `perf` group
# What this lint catches
## `clone`/`to_owned`
```rust
let s = String::new();
let t = s.clone();
```
```rust
// MIR
_1 = String::new();
_2 = &_1;
_3 = clone(_2); // (*)
```
We can turn this `clone` call into a move if
1. `_2` is the sole borrow of `_1` at the statement `(*)`
2. `_1` is not used hereafter
## `Deref` + type-specific `to_owned` method
```rust
let s = std::path::PathBuf::new();
let t = s.to_path_buf();
```
```rust
// MIR
_1 = PathBuf::new();
_2 = &1;
_3 = call deref(_2);
_4 = _3; // Copies borrow
StorageDead(_2);
_5 = Path::to_path_buf(_4); // (*)
```
We can turn this `to_path_buf` call into a move if
1. `_3` `_4` are the sole borrow of `_1` at `(*)`
2. `_1` is not used hereafter
# What this PR introduces
1. `MaybeStorageLive` that determines whether a local lives at a particular location
2. `PossibleBorrowerVisitor` that constructs [`TransitiveRelation`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_data_structures/transitive_relation/struct.TransitiveRelation.html) of possible borrows, e.g. visiting `_2 = &1; _3 = &_2:` will result in `_3 -> _2 -> _1` relation. Then `_3` and `_2` will be counted as possible borrowers of `_1` in the sole-borrow analysis above.
