diff options
Diffstat (limited to '')
| -rw-r--r-- | src/tools/clippy/clippy_lints/src/methods/mod.rs | 967 |
1 files changed, 903 insertions, 64 deletions
diff --git a/src/tools/clippy/clippy_lints/src/methods/mod.rs b/src/tools/clippy/clippy_lints/src/methods/mod.rs index 202fbc1f7..41942b20e 100644 --- a/src/tools/clippy/clippy_lints/src/methods/mod.rs +++ b/src/tools/clippy/clippy_lints/src/methods/mod.rs @@ -1,5 +1,8 @@ mod bind_instead_of_map; +mod bytecount; +mod bytes_count_to_len; mod bytes_nth; +mod case_sensitive_file_extension_comparisons; mod chars_cmp; mod chars_cmp_with_unwrap; mod chars_last_cmp; @@ -9,6 +12,7 @@ mod chars_next_cmp_with_unwrap; mod clone_on_copy; mod clone_on_ref_ptr; mod cloned_instead_of_copied; +mod collapsible_str_replace; mod err_expect; mod expect_fun_call; mod expect_used; @@ -21,6 +25,7 @@ mod filter_next; mod flat_map_identity; mod flat_map_option; mod from_iter_instead_of_collect; +mod get_first; mod get_last_with_len; mod get_unwrap; mod implicit_clone; @@ -33,55 +38,72 @@ mod iter_count; mod iter_next_slice; mod iter_nth; mod iter_nth_zero; +mod iter_on_single_or_empty_collections; mod iter_overeager_cloned; mod iter_skip_next; mod iter_with_drain; mod iterator_step_by_zero; +mod manual_ok_or; mod manual_saturating_arithmetic; mod manual_str_repeat; +mod map_clone; mod map_collect_result_unit; +mod map_err_ignore; mod map_flatten; mod map_identity; mod map_unwrap_or; +mod mut_mutex_lock; mod needless_option_as_deref; mod needless_option_take; mod no_effect_replace; mod obfuscated_if_else; mod ok_expect; +mod open_options; mod option_as_ref_deref; mod option_map_or_none; mod option_map_unwrap_or; mod or_fun_call; mod or_then_unwrap; +mod path_buf_push_overwrite; +mod range_zip_with_len; +mod repeat_once; mod search_is_some; mod single_char_add_str; mod single_char_insert_string; mod single_char_pattern; mod single_char_push_string; mod skip_while_next; +mod stable_sort_primitive; mod str_splitn; mod string_extend_chars; mod suspicious_map; mod suspicious_splitn; +mod suspicious_to_owned; mod uninit_assumed_init; +mod unit_hash; mod unnecessary_filter_map; mod unnecessary_fold; mod unnecessary_iter_cloned; mod unnecessary_join; mod unnecessary_lazy_eval; +mod unnecessary_sort_by; mod unnecessary_to_owned; mod unwrap_or_else_default; mod unwrap_used; mod useless_asref; mod utils; +mod vec_resize_to_zero; +mod verbose_file_reads; mod wrong_self_convention; mod zst_offset; use bind_instead_of_map::BindInsteadOfMap; use clippy_utils::consts::{constant, Constant}; use clippy_utils::diagnostics::{span_lint, span_lint_and_help}; -use clippy_utils::ty::{contains_adt_constructor, contains_ty, implements_trait, is_copy, is_type_diagnostic_item}; -use clippy_utils::{contains_return, get_trait_def_id, iter_input_pats, meets_msrv, msrvs, paths, return_ty}; +use clippy_utils::ty::{contains_adt_constructor, implements_trait, is_copy, is_type_diagnostic_item}; +use clippy_utils::{ + contains_return, get_trait_def_id, is_trait_method, iter_input_pats, meets_msrv, msrvs, paths, return_ty, +}; use if_chain::if_chain; use rustc_hir as hir; use rustc_hir::def::Res; @@ -119,6 +141,32 @@ declare_clippy_lint! { declare_clippy_lint! { /// ### What it does + /// Checks for consecutive calls to `str::replace` (2 or more) + /// that can be collapsed into a single call. + /// + /// ### Why is this bad? + /// Consecutive `str::replace` calls scan the string multiple times + /// with repetitive code. + /// + /// ### Example + /// ```rust + /// let hello = "hesuo worpd" + /// .replace('s', "l") + /// .replace("u", "l") + /// .replace('p', "l"); + /// ``` + /// Use instead: + /// ```rust + /// let hello = "hesuo worpd".replace(&['s', 'u', 'p'], "l"); + /// ``` + #[clippy::version = "1.64.0"] + pub COLLAPSIBLE_STR_REPLACE, + perf, + "collapse consecutive calls to str::replace (2 or more) into a single call" +} + +declare_clippy_lint! { + /// ### What it does /// Checks for usage of `_.cloned().<func>()` where call to `.cloned()` can be postponed. /// /// ### Why is this bad? @@ -173,7 +221,7 @@ declare_clippy_lint! { declare_clippy_lint! { /// ### What it does - /// Checks for `.unwrap()` calls on `Option`s and on `Result`s. + /// Checks for `.unwrap()` or `.unwrap_err()` calls on `Result`s and `.unwrap()` call on `Option`s. /// /// ### Why is this bad? /// It is better to handle the `None` or `Err` case, @@ -204,6 +252,17 @@ declare_clippy_lint! { /// option.expect("more helpful message"); /// result.expect("more helpful message"); /// ``` + /// + /// If [expect_used](#expect_used) is enabled, instead: + /// ```rust,ignore + /// # let option = Some(1); + /// # let result: Result<usize, ()> = Ok(1); + /// option?; + /// + /// // or + /// + /// result?; + /// ``` #[clippy::version = "1.45.0"] pub UNWRAP_USED, restriction, @@ -212,7 +271,7 @@ declare_clippy_lint! { declare_clippy_lint! { /// ### What it does - /// Checks for `.expect()` calls on `Option`s and `Result`s. + /// Checks for `.expect()` or `.expect_err()` calls on `Result`s and `.expect()` call on `Option`s. /// /// ### Why is this bad? /// Usually it is better to handle the `None` or `Err` case. @@ -766,8 +825,9 @@ declare_clippy_lint! { declare_clippy_lint! { /// ### What it does /// Checks for calls to `.or(foo(..))`, `.unwrap_or(foo(..))`, - /// etc., and suggests to use `or_else`, `unwrap_or_else`, etc., or - /// `unwrap_or_default` instead. + /// `.or_insert(foo(..))` etc., and suggests to use `.or_else(|| foo(..))`, + /// `.unwrap_or_else(|| foo(..))`, `.unwrap_or_default()` or `.or_default()` + /// etc. instead. /// /// ### Why is this bad? /// The function will always be called and potentially @@ -1997,6 +2057,55 @@ declare_clippy_lint! { declare_clippy_lint! { /// ### What it does + /// Checks for the usage of `_.to_owned()`, on a `Cow<'_, _>`. + /// + /// ### Why is this bad? + /// Calling `to_owned()` on a `Cow` creates a clone of the `Cow` + /// itself, without taking ownership of the `Cow` contents (i.e. + /// it's equivalent to calling `Cow::clone`). + /// The similarly named `into_owned` method, on the other hand, + /// clones the `Cow` contents, effectively turning any `Cow::Borrowed` + /// into a `Cow::Owned`. + /// + /// Given the potential ambiguity, consider replacing `to_owned` + /// with `clone` for better readability or, if getting a `Cow::Owned` + /// was the original intent, using `into_owned` instead. + /// + /// ### Example + /// ```rust + /// # use std::borrow::Cow; + /// let s = "Hello world!"; + /// let cow = Cow::Borrowed(s); + /// + /// let data = cow.to_owned(); + /// assert!(matches!(data, Cow::Borrowed(_))) + /// ``` + /// Use instead: + /// ```rust + /// # use std::borrow::Cow; + /// let s = "Hello world!"; + /// let cow = Cow::Borrowed(s); + /// + /// let data = cow.clone(); + /// assert!(matches!(data, Cow::Borrowed(_))) + /// ``` + /// or + /// ```rust + /// # use std::borrow::Cow; + /// let s = "Hello world!"; + /// let cow = Cow::Borrowed(s); + /// + /// let data = cow.into_owned(); + /// assert!(matches!(data, String)) + /// ``` + #[clippy::version = "1.65.0"] + pub SUSPICIOUS_TO_OWNED, + suspicious, + "calls to `to_owned` on a `Cow<'_, _>` might not do what they are expected" +} + +declare_clippy_lint! { + /// ### What it does /// Checks for calls to [`splitn`] /// (https://doc.rust-lang.org/std/primitive.str.html#method.splitn) and /// related functions with either zero or one splits. @@ -2258,7 +2367,7 @@ declare_clippy_lint! { /// "1234".replace("12", "12"); /// "1234".replacen("12", "12", 1); /// ``` - #[clippy::version = "1.62.0"] + #[clippy::version = "1.63.0"] pub NO_EFFECT_REPLACE, suspicious, "replace with no effect" @@ -2293,6 +2402,640 @@ declare_clippy_lint! { more clearly with `if .. else ..`" } +declare_clippy_lint! { + /// ### What it does + /// + /// Checks for calls to `iter`, `iter_mut` or `into_iter` on collections containing a single item + /// + /// ### Why is this bad? + /// + /// It is simpler to use the once function from the standard library: + /// + /// ### Example + /// + /// ```rust + /// let a = [123].iter(); + /// let b = Some(123).into_iter(); + /// ``` + /// Use instead: + /// ```rust + /// use std::iter; + /// let a = iter::once(&123); + /// let b = iter::once(123); + /// ``` + /// + /// ### Known problems + /// + /// The type of the resulting iterator might become incompatible with its usage + #[clippy::version = "1.64.0"] + pub ITER_ON_SINGLE_ITEMS, + nursery, + "Iterator for array of length 1" +} + +declare_clippy_lint! { + /// ### What it does + /// + /// Checks for calls to `iter`, `iter_mut` or `into_iter` on empty collections + /// + /// ### Why is this bad? + /// + /// It is simpler to use the empty function from the standard library: + /// + /// ### Example + /// + /// ```rust + /// use std::{slice, option}; + /// let a: slice::Iter<i32> = [].iter(); + /// let f: option::IntoIter<i32> = None.into_iter(); + /// ``` + /// Use instead: + /// ```rust + /// use std::iter; + /// let a: iter::Empty<i32> = iter::empty(); + /// let b: iter::Empty<i32> = iter::empty(); + /// ``` + /// + /// ### Known problems + /// + /// The type of the resulting iterator might become incompatible with its usage + #[clippy::version = "1.64.0"] + pub ITER_ON_EMPTY_COLLECTIONS, + nursery, + "Iterator for empty array" +} + +declare_clippy_lint! { + /// ### What it does + /// Checks for naive byte counts + /// + /// ### Why is this bad? + /// The [`bytecount`](https://crates.io/crates/bytecount) + /// crate has methods to count your bytes faster, especially for large slices. + /// + /// ### Known problems + /// If you have predominantly small slices, the + /// `bytecount::count(..)` method may actually be slower. However, if you can + /// ensure that less than 2³²-1 matches arise, the `naive_count_32(..)` can be + /// faster in those cases. + /// + /// ### Example + /// ```rust + /// # let vec = vec![1_u8]; + /// let count = vec.iter().filter(|x| **x == 0u8).count(); + /// ``` + /// + /// Use instead: + /// ```rust,ignore + /// # let vec = vec![1_u8]; + /// let count = bytecount::count(&vec, 0u8); + /// ``` + #[clippy::version = "pre 1.29.0"] + pub NAIVE_BYTECOUNT, + pedantic, + "use of naive `<slice>.filter(|&x| x == y).count()` to count byte values" +} + +declare_clippy_lint! { + /// ### What it does + /// It checks for `str::bytes().count()` and suggests replacing it with + /// `str::len()`. + /// + /// ### Why is this bad? + /// `str::bytes().count()` is longer and may not be as performant as using + /// `str::len()`. + /// + /// ### Example + /// ```rust + /// "hello".bytes().count(); + /// String::from("hello").bytes().count(); + /// ``` + /// Use instead: + /// ```rust + /// "hello".len(); + /// String::from("hello").len(); + /// ``` + #[clippy::version = "1.62.0"] + pub BYTES_COUNT_TO_LEN, + complexity, + "Using `bytes().count()` when `len()` performs the same functionality" +} + +declare_clippy_lint! { + /// ### What it does + /// Checks for calls to `ends_with` with possible file extensions + /// and suggests to use a case-insensitive approach instead. + /// + /// ### Why is this bad? + /// `ends_with` is case-sensitive and may not detect files with a valid extension. + /// + /// ### Example + /// ```rust + /// fn is_rust_file(filename: &str) -> bool { + /// filename.ends_with(".rs") + /// } + /// ``` + /// Use instead: + /// ```rust + /// fn is_rust_file(filename: &str) -> bool { + /// let filename = std::path::Path::new(filename); + /// filename.extension() + /// .map_or(false, |ext| ext.eq_ignore_ascii_case("rs")) + /// } + /// ``` + #[clippy::version = "1.51.0"] + pub CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS, + pedantic, + "Checks for calls to ends_with with case-sensitive file extensions" +} + +declare_clippy_lint! { + /// ### What it does + /// Checks for using `x.get(0)` instead of + /// `x.first()`. + /// + /// ### Why is this bad? + /// Using `x.first()` is easier to read and has the same + /// result. + /// + /// ### Example + /// ```rust + /// let x = vec![2, 3, 5]; + /// let first_element = x.get(0); + /// ``` + /// + /// Use instead: + /// ```rust + /// let x = vec![2, 3, 5]; + /// let first_element = x.first(); + /// ``` + #[clippy::version = "1.63.0"] + pub GET_FIRST, + style, + "Using `x.get(0)` when `x.first()` is simpler" +} + +declare_clippy_lint! { + /// ### What it does + /// + /// Finds patterns that reimplement `Option::ok_or`. + /// + /// ### Why is this bad? + /// + /// Concise code helps focusing on behavior instead of boilerplate. + /// + /// ### Examples + /// ```rust + /// let foo: Option<i32> = None; + /// foo.map_or(Err("error"), |v| Ok(v)); + /// ``` + /// + /// Use instead: + /// ```rust + /// let foo: Option<i32> = None; + /// foo.ok_or("error"); + /// ``` + #[clippy::version = "1.49.0"] + pub MANUAL_OK_OR, + pedantic, + "finds patterns that can be encoded more concisely with `Option::ok_or`" +} + +declare_clippy_lint! { + /// ### What it does + /// Checks for usage of `map(|x| x.clone())` or + /// dereferencing closures for `Copy` types, on `Iterator` or `Option`, + /// and suggests `cloned()` or `copied()` instead + /// + /// ### Why is this bad? + /// Readability, this can be written more concisely + /// + /// ### Example + /// ```rust + /// let x = vec![42, 43]; + /// let y = x.iter(); + /// let z = y.map(|i| *i); + /// ``` + /// + /// The correct use would be: + /// + /// ```rust + /// let x = vec![42, 43]; + /// let y = x.iter(); + /// let z = y.cloned(); + /// ``` + #[clippy::version = "pre 1.29.0"] + pub MAP_CLONE, + style, + "using `iterator.map(|x| x.clone())`, or dereferencing closures for `Copy` types" +} + +declare_clippy_lint! { + /// ### What it does + /// Checks for instances of `map_err(|_| Some::Enum)` + /// + /// ### Why is this bad? + /// This `map_err` throws away the original error rather than allowing the enum to contain and report the cause of the error + /// + /// ### Example + /// Before: + /// ```rust + /// use std::fmt; + /// + /// #[derive(Debug)] + /// enum Error { + /// Indivisible, + /// Remainder(u8), + /// } + /// + /// impl fmt::Display for Error { + /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + /// match self { + /// Error::Indivisible => write!(f, "could not divide input by three"), + /// Error::Remainder(remainder) => write!( + /// f, + /// "input is not divisible by three, remainder = {}", + /// remainder + /// ), + /// } + /// } + /// } + /// + /// impl std::error::Error for Error {} + /// + /// fn divisible_by_3(input: &str) -> Result<(), Error> { + /// input + /// .parse::<i32>() + /// .map_err(|_| Error::Indivisible) + /// .map(|v| v % 3) + /// .and_then(|remainder| { + /// if remainder == 0 { + /// Ok(()) + /// } else { + /// Err(Error::Remainder(remainder as u8)) + /// } + /// }) + /// } + /// ``` + /// + /// After: + /// ```rust + /// use std::{fmt, num::ParseIntError}; + /// + /// #[derive(Debug)] + /// enum Error { + /// Indivisible(ParseIntError), + /// Remainder(u8), + /// } + /// + /// impl fmt::Display for Error { + /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + /// match self { + /// Error::Indivisible(_) => write!(f, "could not divide input by three"), + /// Error::Remainder(remainder) => write!( + /// f, + /// "input is not divisible by three, remainder = {}", + /// remainder + /// ), + /// } + /// } + /// } + /// + /// impl std::error::Error for Error { + /// fn source(&self) -> Option<&(dyn std::error::Error + 'static)> { + /// match self { + /// Error::Indivisible(source) => Some(source), + /// _ => None, + /// } + /// } + /// } + /// + /// fn divisible_by_3(input: &str) -> Result<(), Error> { + /// input + /// .parse::<i32>() + /// .map_err(Error::Indivisible) + /// .map(|v| v % 3) + /// .and_then(|remainder| { + /// if remainder == 0 { + /// Ok(()) + /// } else { + /// Err(Error::Remainder(remainder as u8)) + /// } + /// }) + /// } + /// ``` + #[clippy::version = "1.48.0"] + pub MAP_ERR_IGNORE, + restriction, + "`map_err` should not ignore the original error" +} + +declare_clippy_lint! { + /// ### What it does + /// Checks for `&mut Mutex::lock` calls + /// + /// ### Why is this bad? + /// `Mutex::lock` is less efficient than + /// calling `Mutex::get_mut`. In addition you also have a statically + /// guarantee that the mutex isn't locked, instead of just a runtime + /// guarantee. + /// + /// ### Example + /// ```rust + /// use std::sync::{Arc, Mutex}; + /// + /// let mut value_rc = Arc::new(Mutex::new(42_u8)); + /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap(); + /// + /// let mut value = value_mutex.lock().unwrap(); + /// *value += 1; + /// ``` + /// Use instead: + /// ```rust + /// use std::sync::{Arc, Mutex}; + /// + /// let mut value_rc = Arc::new(Mutex::new(42_u8)); + /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap(); + /// + /// let value = value_mutex.get_mut().unwrap(); + /// *value += 1; + /// ``` + #[clippy::version = "1.49.0"] + pub MUT_MUTEX_LOCK, + style, + "`&mut Mutex::lock` does unnecessary locking" +} + +declare_clippy_lint! { + /// ### What it does + /// Checks for duplicate open options as well as combinations + /// that make no sense. + /// + /// ### Why is this bad? + /// In the best case, the code will be harder to read than + /// necessary. I don't know the worst case. + /// + /// ### Example + /// ```rust + /// use std::fs::OpenOptions; + /// + /// OpenOptions::new().read(true).truncate(true); + /// ``` + #[clippy::version = "pre 1.29.0"] + pub NONSENSICAL_OPEN_OPTIONS, + correctness, + "nonsensical combination of options for opening a file" +} + +declare_clippy_lint! { + /// ### What it does + ///* Checks for [push](https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.push) + /// calls on `PathBuf` that can cause overwrites. + /// + /// ### Why is this bad? + /// Calling `push` with a root path at the start can overwrite the + /// previous defined path. + /// + /// ### Example + /// ```rust + /// use std::path::PathBuf; + /// + /// let mut x = PathBuf::from("/foo"); + /// x.push("/bar"); + /// assert_eq!(x, PathBuf::from("/bar")); + /// ``` + /// Could be written: + /// + /// ```rust + /// use std::path::PathBuf; + /// + /// let mut x = PathBuf::from("/foo"); + /// x.push("bar"); + /// assert_eq!(x, PathBuf::from("/foo/bar")); + /// ``` + #[clippy::version = "1.36.0"] + pub PATH_BUF_PUSH_OVERWRITE, + nursery, + "calling `push` with file system root on `PathBuf` can overwrite it" +} + +declare_clippy_lint! { + /// ### What it does + /// Checks for zipping a collection with the range of + /// `0.._.len()`. + /// + /// ### Why is this bad? + /// The code is better expressed with `.enumerate()`. + /// + /// ### Example + /// ```rust + /// # let x = vec![1]; + /// let _ = x.iter().zip(0..x.len()); + /// ``` + /// + /// Use instead: + /// ```rust + /// # let x = vec![1]; + /// let _ = x.iter().enumerate(); + /// ``` + #[clippy::version = "pre 1.29.0"] + pub RANGE_ZIP_WITH_LEN, + complexity, + "zipping iterator with a range when `enumerate()` would do" +} + +declare_clippy_lint! { + /// ### What it does + /// Checks for usage of `.repeat(1)` and suggest the following method for each types. + /// - `.to_string()` for `str` + /// - `.clone()` for `String` + /// - `.to_vec()` for `slice` + /// + /// The lint will evaluate constant expressions and values as arguments of `.repeat(..)` and emit a message if + /// they are equivalent to `1`. (Related discussion in [rust-clippy#7306](https://github.com/rust-lang/rust-clippy/issues/7306)) + /// + /// ### Why is this bad? + /// For example, `String.repeat(1)` is equivalent to `.clone()`. If cloning + /// the string is the intention behind this, `clone()` should be used. + /// + /// ### Example + /// ```rust + /// fn main() { + /// let x = String::from("hello world").repeat(1); + /// } + /// ``` + /// Use instead: + /// ```rust + /// fn main() { + /// let x = String::from("hello world").clone(); + /// } + /// ``` + #[clippy::version = "1.47.0"] + pub REPEAT_ONCE, + complexity, + "using `.repeat(1)` instead of `String.clone()`, `str.to_string()` or `slice.to_vec()` " +} + +declare_clippy_lint! { + /// ### What it does + /// When sorting primitive values (integers, bools, chars, as well + /// as arrays, slices, and tuples of such items), it is typically better to + /// use an unstable sort than a stable sort. + /// + /// ### Why is this bad? + /// Typically, using a stable sort consumes more memory and cpu cycles. + /// Because values which compare equal are identical, preserving their + /// relative order (the guarantee that a stable sort provides) means + /// nothing, while the extra costs still apply. + /// + /// ### Known problems + /// + /// As pointed out in + /// [issue #8241](https://github.com/rust-lang/rust-clippy/issues/8241), + /// a stable sort can instead be significantly faster for certain scenarios + /// (eg. when a sorted vector is extended with new data and resorted). + /// + /// For more information and benchmarking results, please refer to the + /// issue linked above. + /// + /// ### Example + /// ```rust + /// let mut vec = vec![2, 1, 3]; + /// vec.sort(); + /// ``` + /// Use instead: + /// ```rust + /// let mut vec = vec![2, 1, 3]; + /// vec.sort_unstable(); + /// ``` + #[clippy::version = "1.47.0"] + pub STABLE_SORT_PRIMITIVE, + pedantic, + "use of sort() when sort_unstable() is equivalent" +} + +declare_clippy_lint! { + /// ### What it does + /// Detects `().hash(_)`. + /// + /// ### Why is this bad? + /// Hashing a unit value doesn't do anything as the implementation of `Hash` for `()` is a no-op. + /// + /// ### Example + /// ```rust + /// # use std::hash::Hash; + /// # use std::collections::hash_map::DefaultHasher; + /// # enum Foo { Empty, WithValue(u8) } + /// # use Foo::*; + /// # let mut state = DefaultHasher::new(); + /// # let my_enum = Foo::Empty; + /// match my_enum { + /// Empty => ().hash(&mut state), + /// WithValue(x) => x.hash(&mut state), + /// } + /// ``` + /// Use instead: + /// ```rust + /// # use std::hash::Hash; + /// # use std::collections::hash_map::DefaultHasher; + /// # enum Foo { Empty, WithValue(u8) } + /// # use Foo::*; + /// # let mut state = DefaultHasher::new(); + /// # let my_enum = Foo::Empty; + /// match my_enum { + /// Empty => 0_u8.hash(&mut state), + /// WithValue(x) => x.hash(&mut state), + /// } + /// ``` + #[clippy::version = "1.58.0"] + pub UNIT_HASH, + correctness, + "hashing a unit value, which does nothing" +} + +declare_clippy_lint! { + /// ### What it does + /// Detects uses of `Vec::sort_by` passing in a closure + /// which compares the two arguments, either directly or indirectly. + /// + /// ### Why is this bad? + /// It is more clear to use `Vec::sort_by_key` (or `Vec::sort` if + /// possible) than to use `Vec::sort_by` and a more complicated + /// closure. + /// + /// ### Known problems + /// If the suggested `Vec::sort_by_key` uses Reverse and it isn't already + /// imported by a use statement, then it will need to be added manually. + /// + /// ### Example + /// ```rust + /// # struct A; + /// # impl A { fn foo(&self) {} } + /// # let mut vec: Vec<A> = Vec::new(); + /// vec.sort_by(|a, b| a.foo().cmp(&b.foo())); + /// ``` + /// Use instead: + /// ```rust + /// # struct A; + /// # impl A { fn foo(&self) {} } + /// # let mut vec: Vec<A> = Vec::new(); + /// vec.sort_by_key(|a| a.foo()); + /// ``` + #[clippy::version = "1.46.0"] + pub UNNECESSARY_SORT_BY, + complexity, + "Use of `Vec::sort_by` when `Vec::sort_by_key` or `Vec::sort` would be clearer" +} + +declare_clippy_lint! { + /// ### What it does + /// Finds occurrences of `Vec::resize(0, an_int)` + /// + /// ### Why is this bad? + /// This is probably an argument inversion mistake. + /// + /// ### Example + /// ```rust + /// vec!(1, 2, 3, 4, 5).resize(0, 5) + /// ``` + /// + /// Use instead: + /// ```rust + /// vec!(1, 2, 3, 4, 5).clear() + /// ``` + #[clippy::version = "1.46.0"] + pub VEC_RESIZE_TO_ZERO, + correctness, + "emptying a vector with `resize(0, an_int)` instead of `clear()` is probably an argument inversion mistake" +} + +declare_clippy_lint! { + /// ### What it does + /// Checks for use of File::read_to_end and File::read_to_string. + /// + /// ### Why is this bad? + /// `fs::{read, read_to_string}` provide the same functionality when `buf` is empty with fewer imports and no intermediate values. + /// See also: [fs::read docs](https://doc.rust-lang.org/std/fs/fn.read.html), [fs::read_to_string docs](https://doc.rust-lang.org/std/fs/fn.read_to_string.html) + /// + /// ### Example + /// ```rust,no_run + /// # use std::io::Read; + /// # use std::fs::File; + /// let mut f = File::open("foo.txt").unwrap(); + /// let mut bytes = Vec::new(); + /// f.read_to_end(&mut bytes).unwrap(); + /// ``` + /// Can be written more concisely as + /// ```rust,no_run + /// # use std::fs; + /// let mut bytes = fs::read("foo.txt").unwrap(); + /// ``` + #[clippy::version = "1.44.0"] + pub VERBOSE_FILE_READS, + restriction, + "use of `File::read_to_end` or `File::read_to_string`" +} + pub struct Methods { avoid_breaking_exported_api: bool, msrv: Option<RustcVersion>, @@ -2336,6 +3079,7 @@ impl_lint_pass!(Methods => [ CLONE_ON_COPY, CLONE_ON_REF_PTR, CLONE_DOUBLE_REF, + COLLAPSIBLE_STR_REPLACE, ITER_OVEREAGER_CLONED, CLONED_INSTEAD_OF_COPIED, FLAT_MAP_OPTION, @@ -2382,6 +3126,7 @@ impl_lint_pass!(Methods => [ FROM_ITER_INSTEAD_OF_COLLECT, INSPECT_FOR_EACH, IMPLICIT_CLONE, + SUSPICIOUS_TO_OWNED, SUSPICIOUS_SPLITN, MANUAL_STR_REPEAT, EXTEND_WITH_DRAIN, @@ -2395,14 +3140,35 @@ impl_lint_pass!(Methods => [ NEEDLESS_OPTION_TAKE, NO_EFFECT_REPLACE, OBFUSCATED_IF_ELSE, + ITER_ON_SINGLE_ITEMS, + ITER_ON_EMPTY_COLLECTIONS, + NAIVE_BYTECOUNT, + BYTES_COUNT_TO_LEN, + CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS, + GET_FIRST, + MANUAL_OK_OR, + MAP_CLONE, + MAP_ERR_IGNORE, + MUT_MUTEX_LOCK, + NONSENSICAL_OPEN_OPTIONS, + PATH_BUF_PUSH_OVERWRITE, + RANGE_ZIP_WITH_LEN, + REPEAT_ONCE, + STABLE_SORT_PRIMITIVE, + UNIT_HASH, + UNNECESSARY_SORT_BY, + VEC_RESIZE_TO_ZERO, + VERBOSE_FILE_READS, ]); /// Extracts a method call name, args, and `Span` of the method name. -fn method_call<'tcx>(recv: &'tcx hir::Expr<'tcx>) -> Option<(&'tcx str, &'tcx [hir::Expr<'tcx>], Span)> { - if let ExprKind::MethodCall(path, args, _) = recv.kind { - if !args.iter().any(|e| e.span.from_expansion()) { +fn method_call<'tcx>( + recv: &'tcx hir::Expr<'tcx>, +) -> Option<(&'tcx str, &'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>], Span)> { + if let ExprKind::MethodCall(path, receiver, args, _) = recv.kind { + if !args.iter().any(|e| e.span.from_expansion()) && !receiver.span.from_expansion() { let name = path.ident.name.as_str(); - return Some((name, args, path.ident.span)); + return Some((name, receiver, args, path.ident.span)); } } None @@ -2420,17 +3186,17 @@ impl<'tcx> LateLintPass<'tcx> for Methods { hir::ExprKind::Call(func, args) => { from_iter_instead_of_collect::check(cx, expr, args, func); }, - hir::ExprKind::MethodCall(method_call, args, _) => { + hir::ExprKind::MethodCall(method_call, receiver, args, _) => { let method_span = method_call.ident.span; - or_fun_call::check(cx, expr, method_span, method_call.ident.as_str(), args); - expect_fun_call::check(cx, expr, method_span, method_call.ident.as_str(), args); - clone_on_copy::check(cx, expr, method_call.ident.name, args); - clone_on_ref_ptr::check(cx, expr, method_call.ident.name, args); - inefficient_to_string::check(cx, expr, method_call.ident.name, args); - single_char_add_str::check(cx, expr, args); - into_iter_on_ref::check(cx, expr, method_span, method_call.ident.name, args); - single_char_pattern::check(cx, expr, method_call.ident.name, args); - unnecessary_to_owned::check(cx, expr, method_call.ident.name, args, self.msrv); + or_fun_call::check(cx, expr, method_span, method_call.ident.as_str(), receiver, args); + expect_fun_call::check(cx, expr, method_span, method_call.ident.as_str(), receiver, args); + clone_on_copy::check(cx, expr, method_call.ident.name, receiver, args); + clone_on_ref_ptr::check(cx, expr, method_call.ident.name, receiver, args); + inefficient_to_string::check(cx, expr, method_call.ident.name, receiver, args); + single_char_add_str::check(cx, expr, receiver, args); + into_iter_on_ref::check(cx, expr, method_span, method_call.ident.name, receiver); + single_char_pattern::check(cx, expr, method_call.ident.name, receiver, args); + unnecessary_to_owned::check(cx, expr, method_call.ident.name, receiver, args, self.msrv); }, hir::ExprKind::Binary(op, lhs, rhs) if op.node == hir::BinOpKind::Eq || op.node == hir::BinOpKind::Ne => { let mut info = BinaryExprInfo { @@ -2530,7 +3296,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods { if contains_adt_constructor(ret_ty, self_adt) { return; } - } else if contains_ty(ret_ty, self_ty) { + } else if ret_ty.contains(self_ty) { return; } @@ -2539,16 +3305,16 @@ impl<'tcx> LateLintPass<'tcx> for Methods { // one of the associated types must be Self for &(predicate, _span) in cx.tcx.explicit_item_bounds(def_id) { if let ty::PredicateKind::Projection(projection_predicate) = predicate.kind().skip_binder() { - let assoc_ty = match projection_predicate.term { - ty::Term::Ty(ty) => ty, - ty::Term::Const(_c) => continue, + let assoc_ty = match projection_predicate.term.unpack() { + ty::TermKind::Ty(ty) => ty, + ty::TermKind::Const(_c) => continue, }; // walk the associated type and check for Self if let Some(self_adt) = self_ty.ty_adt_def() { if contains_adt_constructor(assoc_ty, self_adt) { return; } - } else if contains_ty(assoc_ty, self_ty) { + } else if assoc_ty.contains(self_ty) { return; } } @@ -2597,7 +3363,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods { if let TraitItemKind::Fn(_, _) = item.kind; let ret_ty = return_ty(cx, item.hir_id()); let self_ty = TraitRef::identity(cx.tcx, item.def_id.to_def_id()).self_ty().skip_binder(); - if !contains_ty(ret_ty, self_ty); + if !ret_ty.contains(self_ty); then { span_lint( @@ -2616,7 +3382,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods { impl Methods { #[allow(clippy::too_many_lines)] fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { - if let Some((name, [recv, args @ ..], span)) = method_call(expr) { + if let Some((name, recv, args, span)) = method_call(expr) { match (name, args) { ("add" | "offset" | "sub" | "wrapping_offset" | "wrapping_add" | "wrapping_sub", [_arg]) => { zst_offset::check(cx, expr, recv); @@ -2636,35 +3402,43 @@ impl Methods { ("assume_init", []) => uninit_assumed_init::check(cx, expr, recv), ("cloned", []) => cloned_instead_of_copied::check(cx, expr, recv, span, self.msrv), ("collect", []) => match method_call(recv) { - Some((name @ ("cloned" | "copied"), [recv2], _)) => { + Some((name @ ("cloned" | "copied"), recv2, [], _)) => { iter_cloned_collect::check(cx, name, expr, recv2); }, - Some(("map", [m_recv, m_arg], _)) => { + Some(("map", m_recv, [m_arg], _)) => { map_collect_result_unit::check(cx, expr, m_recv, m_arg, recv); }, - Some(("take", [take_self_arg, take_arg], _)) => { + Some(("take", take_self_arg, [take_arg], _)) => { if meets_msrv(self.msrv, msrvs::STR_REPEAT) { manual_str_repeat::check(cx, expr, recv, take_self_arg, take_arg); } }, _ => {}, }, - ("count", []) => match method_call(recv) { - Some(("cloned", [recv2], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, true, false), - Some((name2 @ ("into_iter" | "iter" | "iter_mut"), [recv2], _)) => { + ("count", []) if is_trait_method(cx, expr, sym::Iterator) => match method_call(recv) { + Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, true, false), + Some((name2 @ ("into_iter" | "iter" | "iter_mut"), recv2, [], _)) => { iter_count::check(cx, expr, recv2, name2); }, - Some(("map", [_, arg], _)) => suspicious_map::check(cx, expr, recv, arg), + Some(("map", _, [arg], _)) => suspicious_map::check(cx, expr, recv, arg), + Some(("filter", recv2, [arg], _)) => bytecount::check(cx, expr, recv2, arg), + Some(("bytes", recv2, [], _)) => bytes_count_to_len::check(cx, expr, recv, recv2), _ => {}, }, ("drain", [arg]) => { iter_with_drain::check(cx, expr, recv, span, arg); }, + ("ends_with", [arg]) => { + if let ExprKind::MethodCall(.., span) = expr.kind { + case_sensitive_file_extension_comparisons::check(cx, expr, span, recv, arg); + } + }, ("expect", [_]) => match method_call(recv) { - Some(("ok", [recv], _)) => ok_expect::check(cx, expr, recv), - Some(("err", [recv], err_span)) => err_expect::check(cx, expr, recv, self.msrv, span, err_span), - _ => expect_used::check(cx, expr, recv, self.allow_expect_in_tests), + Some(("ok", recv, [], _)) => ok_expect::check(cx, expr, recv), + Some(("err", recv, [], err_span)) => err_expect::check(cx, expr, recv, self.msrv, span, err_span), + _ => expect_used::check(cx, expr, recv, false, self.allow_expect_in_tests), }, + ("expect_err", [_]) => expect_used::check(cx, expr, recv, true, self.allow_expect_in_tests), ("extend", [arg]) => { string_extend_chars::check(cx, expr, recv, arg); extend_with_drain::check(cx, expr, recv, arg); @@ -2681,36 +3455,53 @@ impl Methods { flat_map_option::check(cx, expr, arg, span); }, ("flatten", []) => match method_call(recv) { - Some(("map", [recv, map_arg], map_span)) => map_flatten::check(cx, expr, recv, map_arg, map_span), - Some(("cloned", [recv2], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, true), + Some(("map", recv, [map_arg], map_span)) => map_flatten::check(cx, expr, recv, map_arg, map_span), + Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, true), _ => {}, }, ("fold", [init, acc]) => unnecessary_fold::check(cx, expr, init, acc, span), ("for_each", [_]) => { - if let Some(("inspect", [_, _], span2)) = method_call(recv) { + if let Some(("inspect", _, [_], span2)) = method_call(recv) { inspect_for_each::check(cx, expr, span2); } }, - ("get", [arg]) => get_last_with_len::check(cx, expr, recv, arg), + ("get", [arg]) => { + get_first::check(cx, expr, recv, arg); + get_last_with_len::check(cx, expr, recv, arg); + }, ("get_or_insert_with", [arg]) => unnecessary_lazy_eval::check(cx, expr, recv, arg, "get_or_insert"), + ("hash", [arg]) => { + unit_hash::check(cx, expr, recv, arg); + }, ("is_file", []) => filetype_is_file::check(cx, expr, recv), ("is_digit", [radix]) => is_digit_ascii_radix::check(cx, expr, recv, radix, self.msrv), ("is_none", []) => check_is_some_is_none(cx, expr, recv, false), ("is_some", []) => check_is_some_is_none(cx, expr, recv, true), + ("iter" | "iter_mut" | "into_iter", []) => { + iter_on_single_or_empty_collections::check(cx, expr, name, recv); + }, ("join", [join_arg]) => { - if let Some(("collect", _, span)) = method_call(recv) { + if let Some(("collect", _, _, span)) = method_call(recv) { unnecessary_join::check(cx, expr, recv, join_arg, span); } }, ("last", []) | ("skip", [_]) => { - if let Some((name2, [recv2, args2 @ ..], _span2)) = method_call(recv) { + if let Some((name2, recv2, args2, _span2)) = method_call(recv) { if let ("cloned", []) = (name2, args2) { iter_overeager_cloned::check(cx, expr, recv, recv2, false, false); } } }, + ("lock", []) => { + mut_mutex_lock::check(cx, expr, recv, span); + }, (name @ ("map" | "map_err"), [m_arg]) => { - if let Some((name, [recv2, args @ ..], span2)) = method_call(recv) { + if name == "map" { + map_clone::check(cx, expr, recv, m_arg, self.msrv); + } else { + map_err_ignore::check(cx, expr, m_arg); + } + if let Some((name, recv2, args, span2)) = method_call(recv) { match (name, args) { ("as_mut", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, true, self.msrv), ("as_ref", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, false, self.msrv), @@ -2725,9 +3516,12 @@ impl Methods { } map_identity::check(cx, expr, recv, m_arg, name, span); }, - ("map_or", [def, map]) => option_map_or_none::check(cx, expr, recv, def, map), + ("map_or", [def, map]) => { + option_map_or_none::check(cx, expr, recv, def, map); + manual_ok_or::check(cx, expr, recv, def, map); + }, ("next", []) => { - if let Some((name2, [recv2, args2 @ ..], _)) = method_call(recv) { + if let Some((name2, recv2, args2, _)) = method_call(recv) { match (name2, args2) { ("cloned", []) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false), ("filter", [arg]) => filter_next::check(cx, expr, recv2, arg), @@ -2740,18 +3534,53 @@ impl Methods { } }, ("nth", [n_arg]) => match method_call(recv) { - Some(("bytes", [recv2], _)) => bytes_nth::check(cx, expr, recv2, n_arg), - Some(("cloned", [recv2], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false), - Some(("iter", [recv2], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, false), - Some(("iter_mut", [recv2], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, true), + Some(("bytes", recv2, [], _)) => bytes_nth::check(cx, expr, recv2, n_arg), + Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false), + Some(("iter", recv2, [], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, false), + Some(("iter_mut", recv2, [], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, true), _ => iter_nth_zero::check(cx, expr, recv, n_arg), }, ("ok_or_else", [arg]) => unnecessary_lazy_eval::check(cx, expr, recv, arg, "ok_or"), + ("open", [_]) => { + open_options::check(cx, expr, recv); + }, ("or_else", [arg]) => { if !bind_instead_of_map::ResultOrElseErrInfo::check(cx, expr, recv, arg) { unnecessary_lazy_eval::check(cx, expr, recv, arg, "or"); } }, + ("push", [arg]) => { + path_buf_push_overwrite::check(cx, expr, arg); + }, + ("read_to_end", [_]) => { + verbose_file_reads::check(cx, expr, recv, verbose_file_reads::READ_TO_END_MSG); + }, + ("read_to_string", [_]) => { + verbose_file_reads::check(cx, expr, recv, verbose_file_reads::READ_TO_STRING_MSG); + }, + ("repeat", [arg]) => { + repeat_once::check(cx, expr, recv, arg); + }, + (name @ ("replace" | "replacen"), [arg1, arg2] | [arg1, arg2, _]) => { + no_effect_replace::check(cx, expr, arg1, arg2); + + // Check for repeated `str::replace` calls to perform `collapsible_str_replace` lint + if name == "replace" && let Some(("replace", ..)) = method_call(recv) { + collapsible_str_replace::check(cx, expr, arg1, arg2); + } + }, + ("resize", [count_arg, default_arg]) => { + vec_resize_to_zero::check(cx, expr, count_arg, default_arg, span); + }, + ("sort", []) => { + stable_sort_primitive::check(cx, expr, recv); + }, + ("sort_by", [arg]) => { + unnecessary_sort_by::check(cx, expr, recv, arg, false); + }, + ("sort_unstable_by", [arg]) => { + unnecessary_sort_by::check(cx, expr, recv, arg, true); + }, ("splitn" | "rsplitn", [count_arg, pat_arg]) => { if let Some((Constant::Int(count), _)) = constant(cx, cx.typeck_results(), count_arg) { suspicious_splitn::check(cx, name, expr, recv, count); @@ -2765,7 +3594,7 @@ impl Methods { }, ("step_by", [arg]) => iterator_step_by_zero::check(cx, expr, arg), ("take", [_arg]) => { - if let Some((name2, [recv2, args2 @ ..], _span2)) = method_call(recv) { + if let Some((name2, recv2, args2, _span2)) = method_call(recv) { if let ("cloned", []) = (name2, args2) { iter_overeager_cloned::check(cx, expr, recv, recv2, false, false); } @@ -2778,46 +3607,56 @@ impl Methods { } unnecessary_lazy_eval::check(cx, expr, recv, arg, "then_some"); }, - ("to_os_string" | "to_owned" | "to_path_buf" | "to_vec", []) => { + ("to_owned", []) => { + if !suspicious_to_owned::check(cx, expr, recv) { + implicit_clone::check(cx, name, expr, recv); + } + }, + ("to_os_string" | "to_path_buf" | "to_vec", []) => { implicit_clone::check(cx, name, expr, recv); }, ("unwrap", []) => { match method_call(recv) { - Some(("get", [recv, get_arg], _)) => { + Some(("get", recv, [get_arg], _)) => { get_unwrap::check(cx, expr, recv, get_arg, false); }, - Some(("get_mut", [recv, get_arg], _)) => { + Some(("get_mut", recv, [get_arg], _)) => { get_unwrap::check(cx, expr, recv, get_arg, true); }, - Some(("or", [recv, or_arg], or_span)) => { + Some(("or", recv, [or_arg], or_span)) => { or_then_unwrap::check(cx, expr, recv, or_arg, or_span); }, _ => {}, } - unwrap_used::check(cx, expr, recv, self.allow_unwrap_in_tests); + unwrap_used::check(cx, expr, recv, false, self.allow_unwrap_in_tests); }, + ("unwrap_err", []) => unwrap_used::check(cx, expr, recv, true, self.allow_unwrap_in_tests), ("unwrap_or", [u_arg]) => match method_call(recv) { - Some((arith @ ("checked_add" | "checked_sub" | "checked_mul"), [lhs, rhs], _)) => { + Some((arith @ ("checked_add" | "checked_sub" | "checked_mul"), lhs, [rhs], _)) => { manual_saturating_arithmetic::check(cx, expr, lhs, rhs, u_arg, &arith["checked_".len()..]); }, - Some(("map", [m_recv, m_arg], span)) => { + Some(("map", m_recv, [m_arg], span)) => { option_map_unwrap_or::check(cx, expr, m_recv, m_arg, recv, u_arg, span); }, - Some(("then_some", [t_recv, t_arg], _)) => { + Some(("then_some", t_recv, [t_arg], _)) => { obfuscated_if_else::check(cx, expr, t_recv, t_arg, u_arg); }, _ => {}, }, ("unwrap_or_else", [u_arg]) => match method_call(recv) { - Some(("map", [recv, map_arg], _)) + Some(("map", recv, [map_arg], _)) if map_unwrap_or::check(cx, expr, recv, map_arg, u_arg, self.msrv) => {}, _ => { unwrap_or_else_default::check(cx, expr, recv, u_arg); unnecessary_lazy_eval::check(cx, expr, recv, u_arg, "unwrap_or"); }, }, - ("replace" | "replacen", [arg1, arg2] | [arg1, arg2, _]) => { - no_effect_replace::check(cx, expr, arg1, arg2); + ("zip", [arg]) => { + if let ExprKind::MethodCall(name, iter_recv, [], _) = recv.kind + && name.ident.name == sym::iter + { + range_zip_with_len::check(cx, expr, iter_recv, arg); + } }, _ => {}, } @@ -2826,7 +3665,7 @@ impl Methods { } fn check_is_some_is_none(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, is_some: bool) { - if let Some((name @ ("find" | "position" | "rposition"), [f_recv, arg], span)) = method_call(recv) { + if let Some((name @ ("find" | "position" | "rposition"), f_recv, [arg], span)) = method_call(recv) { search_is_some::check(cx, expr, name, is_some, f_recv, arg, recv, span); } } |