Null fn lints
Adds lints to check for code, that assumes nullable `fn()`.
### Lint examples:
`transmute_null_to_fn`:
```rust
error: transmuting a known null pointer into a function pointer
--> $DIR/transmute_null_to_fn.rs:9:23
|
LL | let _: fn() = std::mem::transmute(std::ptr::null::<()>());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this transmute results in undefined behavior
|
= help: try wrapping your function pointer type in `Option<T>` instead, and using `None` as a null pointer value
```
`fn_null_check`:
```rust
error: function pointer assumed to be nullable, even though it isn't
--> $DIR/fn_null_check.rs:13:8
|
LL | if (fn_ptr as *mut ()).is_null() {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: try wrapping your function pointer type in `Option<T>` instead, and using `is_none` to check for null pointer value
```
Closes#1644
---
changelog: Improvement: [`transmuting_null`]: Now detects `const` pointers to all types
[#10099](https://github.com/rust-lang/rust-clippy/pull/10099)
changelog: New lint: [`transmute_null_to_fn`]
[#10099](https://github.com/rust-lang/rust-clippy/pull/10099)
changelog: New lint: [`fn_null_check`]
[#10099](https://github.com/rust-lang/rust-clippy/pull/10099)
<!-- changelog_checked (This is just a flag for me, please don't add it manually) -->
Identify more cases of useless `into_iter()` calls
changelog: Sugg: [`useless_conversion`]: Now suggests removing calls to `into_iter()` on an expression implementing `Iterator`
[#10020](https://github.com/rust-lang/rust-clippy/pull/10020)
<!-- changelog_checked -->
If the type of the result of a call to `IntoIterator::into_iter()`
and the type of the receiver are the same, then the receiver
implements `Iterator` and `into_iter()` is the identity function.
The call to `into_iter()` may be removed in all but two cases:
- If the receiver implements `Copy`, `into_iter()` will produce
a copy of the receiver and cannot be removed. For example,
`x.into_iter().next()` will not advance `x` while `x.next()` will.
- If the receiver is an immutable local variable and the call to
`into_iter()` appears in a larger expression, removing the call to
`into_iter()` might cause mutability issues. For example, if `x`
is an immutable local variable, `x.into_iter().next()` will
compile while `x.next()` will not as `next()` receives
`&mut self`.
Rustup
r? `@ghost`
I'm on the train and my internet is too bad to download the necessary toolchain, so I have to use CI to find sync fallout.
changelog: none
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fix: not suggest seek_to_start_instead_of_rewind when expr is used
changelog: [`seek_to_start_instead_of_rewind`]: No longer lints, if the return of `seek` is used.
[#10096](https://github.com/rust-lang/rust-clippy/pull/10096)
<!-- changelog_checked -->
Fixes#10065
fix logic in IncrementVisitor
There used to be a logical bug where IncrementVisitor would completely stop checking an expression/block after seeing a continue statement.
I am a little unsure of whether my fix to `IncrementVisitor` is logically sound (I hope it makes sense). Let me know what you think, and thanks in advance for the review!
fixes#10058
---
changelog: FP: [`explicit_counter_loop`]: No longer ignores counter changes after `continue` expressions
[#10094](https://github.com/rust-lang/rust-clippy/pull/10094)
<!-- changelog_checked -->
There used to be a logical bug where IncrementVisitor would
completely stop checking an expression/block after seeing a continue
statement. This led to issue #10058 where a variable incremented
(or otherwise modified) after any continue statement would still be
considered incremented only once.
The solution is to continue scanning the expression after seeing a
`continue` statement, but increment self.depth so that the Visitor
thinks that the rest of the loop is within a conditional.
Changelog 1.66
It's really nice to see a changelog with so many suggestion fixes and improvements. Not much else to say. This should be merged with the coming release on 2022-12-15. For the reviewer, please review it and approve it if it looks good. The merge should wait until the release :)
---
changelog: none
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Cleanup `rustc_tool_util` and add a convenient macro for `build.rs`
changelog: none
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If possible, I'd like to have a new release for this, maybe `v0.3.0` to use the changes in another project. Then we can also remove the `path = "./rustc_tools_util"` from `Cargo.toml`. I'd be happy to help with the release on crates.io if you'd like the help :)
r? `@matthiaskrgr`
improve `manual_is_ascii_check ` check
Sorry, not familiar the api, i can only check the method name of expression `<expr-1>.contains(<expr-2>)` after read clippy book and hints from #9933 . i dont know how to check
1. if <expr-1> is a specific range
2. <expr-2> is a character
r? `@xFrednet` could you please provide some more hints? 😝️
---
changelog: Enhancement: [`manual_is_ascii_check`]: Now detects ranges with `.contains()` calls
[#10053](https://github.com/rust-lang/rust-clippy/pull/10053)
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