Add lint to detect slow zero-filled vector initialization. It detects
when a vector is zero-filled with extended with `repeat(0).take(len)`
or `resize(len, 0)`.
This zero-fillings are usually slower than simply using `vec![0; len]`.
I noticed that I suppress this lint in many of my projects.
https://github.com/search?q=needless_pass_by_value+user%3Adtolnay&type=Codehttps://github.com/search?q=needless_pass_by_value+user%3Aserde-rs&type=Code
Upon further inspection, this lint has a *long* history of false
positives (and several remaining).
Generally I feel that this lint is the definition of pedantic and should
not be linted by default.
#[derive(Debug)]
enum How {
ThisWay,
ThatWay,
}
// Are we really better off forcing the call sites to write f(&_)...?
fn f(how: How) {
println!("You want to do it {:?}", how);
}
fn main() {
f(How::ThatWay);
}
This finishes up the rewrite of `update_lints.py` in Rust. More
specifically, this
* adds the `--check` flag and handling to clippy_dev
* tracks file changes over the different calls to `replace_region_in_file`
* only writes changes to files if the `--check` flag is *not* used
* runs `./util/dev update_lints --check` on CI instead of the old script
* replaces usage of the `update_lints.py` script with an error
`./util/dev update_lints` behaves 99% the same as the python script.
The only difference that I'm aware of is an ordering change to
`clippy_lints/src/lib.rs` because underscores seem to be sorted
differently in Rust and in Python.
🏁
3353: float support added for mistyped_literal_suffixes lint r=mikerite a=Maxgy
I implemented the mistyped_literal_suffixes lint for float literals.
```
#![allow(unused_variables)]
fn main() {
let x = 1E2_32;
let x = 75.22_64;
}
```
Given the above, the additional check suggests the variables to be written as `let x = 1E2_f32` and `let x = 75.22_f64`.
Fixes#3167
Co-authored-by: Maxwell Anderson <maxwell.brayden.anderson@gmail.com>
`possible_missing_comma` should only trigger when the binary operator has
unary equivalent. Otherwise, it's not possible to insert a comma without
breaking compilation. The operators identified were `+`, `&`, `*` and `-`.
This fixes the specific examples given in issues #3244 and #3396
but doesn't address the conflict this lint has with the style of starting
a line with a binary operator.
3388: RIIR update lints: Generate deprecated lints r=phansch a=phansch
The update script now also generates the 'register_removed' section in
`clippy_lints/src/lib.rs`.
Also, instead of using `let mut store ...`, I added a new identifier
line so that the replacement will continue to work in case `let mut
store ...` ever changes.
cc #2882
Co-authored-by: Philipp Hansch <dev@phansch.net>
3368: added downsides to "known problems" for get_unwrap lint r=flip1995 a=humean
As a beginner I found this lint to be confusing because I was not sure how the `Option` type disappeared as conceptually I know that my `.get()` and Index could fail. Initially I thought maybe the compiler or clippy was smart enough to understand that it was impossible for my `.get()` to fail in this particular case, but it was explained to me that using the Index syntax is just shorthand for directly unwrapping the value:
https://doc.rust-lang.org/src/std/collections/hash/map.rs.html#1547
For beginners or users trying to iterate quickly it seems common to litter your code with `unwrap` or `except` as placeholders for where some explicit error handling might need to take place. I think it should be warned that using Index is merely more concise, but doesn't at all reduce the risk of panics and might in fact cause you to miss handling them in a future refactor.
Co-authored-by: Michael Rutter <michael.john.rutter@gmail.com>
Co-authored-by: Michael Rutter <humean@users.noreply.github.com>
The update script now also generates the 'register_removed' section in
`clippy_lints/src/lib.rs`.
Also, instead of using `let mut store ...`, I added a new identifier
line so that the replacement will continue to work in case `let mut
store ...` ever changes.
3217: Fix string_lit_as_bytes lint for macros r=phansch a=yaahallo
Prior to this change, string_lit_as_bytes would trigger for constructs
like `include_str!("filename").as_bytes()` and would recommend fixing it
by rewriting as `binclude_str!("filename")`.
This change updates the lint to act as an EarlyLintPass lint. It then
differentiates between string literals and macros that have bytes
yielding alternatives.
Closes#3205
3366: Don't expand macros in some suggestions r=oli-obk a=phansch
Fixes#1148Fixes#1628Fixes#2455Fixes#3023Fixes#3333Fixes#3360
Co-authored-by: Jane Lusby <jlusby42@gmail.com>
Co-authored-by: Philipp Hansch <dev@phansch.net>
Prior to this change, string_lit_as_bytes would trigger for constructs
like `include_str!("filename").as_bytes()` and would recommend fixing it
by rewriting as `binclude_str!("filename")`.
This change updates the lint to act as an EarlyLintPass lint. It then
differentiates between string literals and macros that have bytes
yielding alternatives.
Closes#3205
3355: Lint to remove redundant `clone()`s r=oli-obk a=sinkuu
This PR adds lint `redundant_clone`. It suggests to remove redundant `clone()` that clones a owned value that will be dropped without any usage after that.
Real-world example: https://github.com/rust-lang/rust/compare/7b0735a..sinkuu:redundant_clone2
Co-authored-by: Shotaro Yamada <sinkuu@sinkuu.xyz>
3331: Disable arithmetic lints in constant items r=oli-obk a=pengowen123
Currently this will not catch cases in associated constants. I'm not sure whether checking spans is the best way to solve this issue, but I don't think it will cause any problems.
Fixes#1858
Co-authored-by: Owen Sanchez <pengowen816@gmail.com>
3356: Fix warnings introduced by #3349 r=flip1995 a=flip1995
I missed these warnings during review, should have checked the Travis log first.
Co-authored-by: flip1995 <hello@philkrones.com>
3338: new_ret_no_self false positives r=flip1995 a=JoshMcguigan
~~WORK IN PROGRESS~~
I plan to fix all of the false positives in #3313 in this PR, but I wanted to open it now to start gathering feedback.
In this first commit, I've updated the lint to allow tuple return types as long as `Self` shows up at least once, in any position of the tuple. I believe this is the broadest possible interpretation of what should be allowed for tuple return types, but I would certainly be okay making the lint more strict.
fixes#3313
Co-authored-by: Josh Mcguigan <joshmcg88@gmail.com>
