X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=README.md;h=121f2c24b4266f94a2468d90a58a78dc85c22fba;hb=115592530548c623c205185e1d3b89ce7ce05b18;hp=fee6d066e7c26669bbf824f88f58f62a1e13a1e3;hpb=106ae7da441c075aa1b83f5c021ea47f25589d05;p=rust.git diff --git a/README.md b/README.md index fee6d066e7c..121f2c24b42 100644 --- a/README.md +++ b/README.md @@ -1,4 +1,5 @@ -#rust-clippy +# rust-clippy + [![Build Status](https://travis-ci.org/Manishearth/rust-clippy.svg?branch=master)](https://travis-ci.org/Manishearth/rust-clippy) [![Clippy Linting Result](http://clippy.bashy.io/github/Manishearth/rust-clippy/master/badge.svg)](http://clippy.bashy.io/github/Manishearth/rust-clippy/master/log) [![Current Version](http://meritbadge.herokuapp.com/clippy)](https://crates.io/crates/clippy) @@ -7,27 +8,31 @@ A collection of lints to catch common mistakes and improve your Rust code. Table of contents: -* [Lint list](#lints) -* [Usage instructions](#usage) -* [Configuration](#configuration) -* [*clippy-service*](#link-with-clippy-service) -* [License](#license) -##Lints -There are 140 lints included in this crate: +* [Lint list](#lints) +* [Usage instructions](#usage) +* [Configuration](#configuration) +* [*clippy-service*](#link-with-clippy-service) +* [License](#license) + +## Lints + +There are 159 lints included in this crate: name | default | meaning ---------------------------------------------------------------------------------------------------------------------|---------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ [absurd_extreme_comparisons](https://github.com/Manishearth/rust-clippy/wiki#absurd_extreme_comparisons) | warn | a comparison involving a maximum or minimum value involves a case that is always true or always false [almost_swapped](https://github.com/Manishearth/rust-clippy/wiki#almost_swapped) | warn | `foo = bar; bar = foo` sequence [approx_constant](https://github.com/Manishearth/rust-clippy/wiki#approx_constant) | warn | the approximate of a known float constant (in `std::f64::consts` or `std::f32::consts`) is found; suggests to use the constant +[assign_op_pattern](https://github.com/Manishearth/rust-clippy/wiki#assign_op_pattern) | warn | assigning the result of an operation on a variable to that same variable +[assign_ops](https://github.com/Manishearth/rust-clippy/wiki#assign_ops) | allow | any assignment operation [bad_bit_mask](https://github.com/Manishearth/rust-clippy/wiki#bad_bit_mask) | warn | expressions of the form `_ & mask == select` that will only ever return `true` or `false` (because in the example `select` containing bits that `mask` doesn't have) [blacklisted_name](https://github.com/Manishearth/rust-clippy/wiki#blacklisted_name) | warn | usage of a blacklisted/placeholder name [block_in_if_condition_expr](https://github.com/Manishearth/rust-clippy/wiki#block_in_if_condition_expr) | warn | braces can be eliminated in conditions that are expressions, e.g `if { true } ...` [block_in_if_condition_stmt](https://github.com/Manishearth/rust-clippy/wiki#block_in_if_condition_stmt) | warn | avoid complex blocks in conditions, instead move the block higher and bind it with 'let'; e.g: `if { let x = true; x } ...` [bool_comparison](https://github.com/Manishearth/rust-clippy/wiki#bool_comparison) | warn | comparing a variable to a boolean, e.g. `if x == true` [box_vec](https://github.com/Manishearth/rust-clippy/wiki#box_vec) | warn | usage of `Box>`, vector elements are already on the heap -[boxed_local](https://github.com/Manishearth/rust-clippy/wiki#boxed_local) | warn | using Box where unnecessary +[boxed_local](https://github.com/Manishearth/rust-clippy/wiki#boxed_local) | warn | using `Box` where unnecessary [cast_possible_truncation](https://github.com/Manishearth/rust-clippy/wiki#cast_possible_truncation) | allow | casts that may cause truncation of the value, e.g `x as u8` where `x: u32`, or `x as i32` where `x: f32` [cast_possible_wrap](https://github.com/Manishearth/rust-clippy/wiki#cast_possible_wrap) | allow | casts that may cause wrapping around the value, e.g `x as i32` where `x: u32` and `x > i32::MAX` [cast_precision_loss](https://github.com/Manishearth/rust-clippy/wiki#cast_precision_loss) | allow | casts that cause loss of precision, e.g `x as f32` where `x: u64` @@ -38,12 +43,13 @@ name [clone_on_copy](https://github.com/Manishearth/rust-clippy/wiki#clone_on_copy) | warn | using `clone` on a `Copy` type [cmp_nan](https://github.com/Manishearth/rust-clippy/wiki#cmp_nan) | deny | comparisons to NAN (which will always return false, which is probably not intended) [cmp_owned](https://github.com/Manishearth/rust-clippy/wiki#cmp_owned) | warn | creating owned instances for comparing with others, e.g. `x == "foo".to_string()` -[collapsible_if](https://github.com/Manishearth/rust-clippy/wiki#collapsible_if) | warn | two nested `if`-expressions can be collapsed into one, e.g. `if x { if y { foo() } }` can be written as `if x && y { foo() }` and an `else { if .. } expression can be collapsed to `else if` +[collapsible_if](https://github.com/Manishearth/rust-clippy/wiki#collapsible_if) | warn | `if`s that can be collapsed (e.g. `if x { if y { ... } }` and `else { if x { ... } }`) [crosspointer_transmute](https://github.com/Manishearth/rust-clippy/wiki#crosspointer_transmute) | warn | transmutes that have to or from types that are a pointer to the other [cyclomatic_complexity](https://github.com/Manishearth/rust-clippy/wiki#cyclomatic_complexity) | warn | finds functions that should be split up into multiple functions [deprecated_semver](https://github.com/Manishearth/rust-clippy/wiki#deprecated_semver) | warn | `Warn` on `#[deprecated(since = "x")]` where x is not semver [derive_hash_xor_eq](https://github.com/Manishearth/rust-clippy/wiki#derive_hash_xor_eq) | warn | deriving `Hash` but implementing `PartialEq` explicitly [doc_markdown](https://github.com/Manishearth/rust-clippy/wiki#doc_markdown) | warn | checks for the presence of `_`, `::` or camel-case outside ticks in documentation +[double_neg](https://github.com/Manishearth/rust-clippy/wiki#double_neg) | warn | `--x` is a double negation of `x` and not a pre-decrement as in C or C++ [drop_ref](https://github.com/Manishearth/rust-clippy/wiki#drop_ref) | warn | call to `std::mem::drop` with a reference instead of an owned value, which will not call the `Drop::drop` method on the underlying value [duplicate_underscore_argument](https://github.com/Manishearth/rust-clippy/wiki#duplicate_underscore_argument) | warn | Function arguments having names which only differ by an underscore [empty_loop](https://github.com/Manishearth/rust-clippy/wiki#empty_loop) | warn | empty `loop {}` detected @@ -55,22 +61,26 @@ name [explicit_counter_loop](https://github.com/Manishearth/rust-clippy/wiki#explicit_counter_loop) | warn | for-looping with an explicit counter when `_.enumerate()` would do [explicit_iter_loop](https://github.com/Manishearth/rust-clippy/wiki#explicit_iter_loop) | warn | for-looping over `_.iter()` or `_.iter_mut()` when `&_` or `&mut _` would do [extend_from_slice](https://github.com/Manishearth/rust-clippy/wiki#extend_from_slice) | warn | `.extend_from_slice(_)` is a faster way to extend a Vec by a slice +[filter_map](https://github.com/Manishearth/rust-clippy/wiki#filter_map) | allow | using combinations of `filter`, `map`, `filter_map` and `flat_map` which can usually be written as a single method call [filter_next](https://github.com/Manishearth/rust-clippy/wiki#filter_next) | warn | using `filter(p).next()`, which is more succinctly expressed as `.find(p)` +[float_arithmetic](https://github.com/Manishearth/rust-clippy/wiki#float_arithmetic) | allow | Any floating-point arithmetic statement [float_cmp](https://github.com/Manishearth/rust-clippy/wiki#float_cmp) | warn | using `==` or `!=` on float values (as floating-point operations usually involve rounding errors, it is always better to check for approximate equality within small bounds) [for_kv_map](https://github.com/Manishearth/rust-clippy/wiki#for_kv_map) | warn | looping on a map using `iter` when `keys` or `values` would do [for_loop_over_option](https://github.com/Manishearth/rust-clippy/wiki#for_loop_over_option) | warn | for-looping over an `Option`, which is more clearly expressed as an `if let` [for_loop_over_result](https://github.com/Manishearth/rust-clippy/wiki#for_loop_over_result) | warn | for-looping over a `Result`, which is more clearly expressed as an `if let` [identity_op](https://github.com/Manishearth/rust-clippy/wiki#identity_op) | warn | using identity operations, e.g. `x + 0` or `y / 1` -[if_not_else](https://github.com/Manishearth/rust-clippy/wiki#if_not_else) | warn | finds if branches that could be swapped so no negation operation is necessary on the condition +[if_not_else](https://github.com/Manishearth/rust-clippy/wiki#if_not_else) | allow | finds if branches that could be swapped so no negation operation is necessary on the condition [if_same_then_else](https://github.com/Manishearth/rust-clippy/wiki#if_same_then_else) | warn | if with the same *then* and *else* blocks [ifs_same_cond](https://github.com/Manishearth/rust-clippy/wiki#ifs_same_cond) | warn | consecutive `ifs` with the same condition [indexing_slicing](https://github.com/Manishearth/rust-clippy/wiki#indexing_slicing) | allow | indexing/slicing usage [ineffective_bit_mask](https://github.com/Manishearth/rust-clippy/wiki#ineffective_bit_mask) | warn | expressions where a bit mask will be rendered useless by a comparison, e.g. `(x | 1) > 2` [inline_always](https://github.com/Manishearth/rust-clippy/wiki#inline_always) | warn | `#[inline(always)]` is a bad idea in most cases -[invalid_regex](https://github.com/Manishearth/rust-clippy/wiki#invalid_regex) | deny | finds invalid regular expressions in `Regex::new(_)` invocations -[invalid_upcast_comparisons](https://github.com/Manishearth/rust-clippy/wiki#invalid_upcast_comparisons) | warn | a comparison involving an upcast which is always true or false -[items_after_statements](https://github.com/Manishearth/rust-clippy/wiki#items_after_statements) | warn | finds blocks where an item comes after a statement +[integer_arithmetic](https://github.com/Manishearth/rust-clippy/wiki#integer_arithmetic) | allow | Any integer arithmetic statement +[invalid_regex](https://github.com/Manishearth/rust-clippy/wiki#invalid_regex) | deny | finds invalid regular expressions +[invalid_upcast_comparisons](https://github.com/Manishearth/rust-clippy/wiki#invalid_upcast_comparisons) | allow | a comparison involving an upcast which is always true or false +[items_after_statements](https://github.com/Manishearth/rust-clippy/wiki#items_after_statements) | allow | finds blocks where an item comes after a statement [iter_next_loop](https://github.com/Manishearth/rust-clippy/wiki#iter_next_loop) | warn | for-looping over `_.next()` which is probably not intended +[iter_nth](https://github.com/Manishearth/rust-clippy/wiki#iter_nth) | warn | using `.iter().nth()` on a standard library type with O(1) element access [len_without_is_empty](https://github.com/Manishearth/rust-clippy/wiki#len_without_is_empty) | warn | traits and impls that have `.len()` but not `.is_empty()` [len_zero](https://github.com/Manishearth/rust-clippy/wiki#len_zero) | warn | checking `.len() == 0` or `.len() > 0` (or similar) when `.is_empty()` could be used instead [let_and_return](https://github.com/Manishearth/rust-clippy/wiki#let_and_return) | warn | creating a let-binding and then immediately returning it like `let x = expr; x` at the end of a block @@ -85,22 +95,27 @@ name [match_overlapping_arm](https://github.com/Manishearth/rust-clippy/wiki#match_overlapping_arm) | warn | a match has overlapping arms [match_ref_pats](https://github.com/Manishearth/rust-clippy/wiki#match_ref_pats) | warn | a match or `if let` has all arms prefixed with `&`; the match expression can be dereferenced instead [match_same_arms](https://github.com/Manishearth/rust-clippy/wiki#match_same_arms) | warn | `match` with identical arm bodies +[mem_forget](https://github.com/Manishearth/rust-clippy/wiki#mem_forget) | allow | `mem::forget` usage on `Drop` types is likely to cause memory leaks [min_max](https://github.com/Manishearth/rust-clippy/wiki#min_max) | warn | `min(_, max(_, _))` (or vice versa) with bounds clamping the result to a constant [modulo_one](https://github.com/Manishearth/rust-clippy/wiki#modulo_one) | warn | taking a number modulo 1, which always returns 0 -[mut_mut](https://github.com/Manishearth/rust-clippy/wiki#mut_mut) | allow | usage of double-mut refs, e.g. `&mut &mut ...` (either copy'n'paste error, or shows a fundamental misunderstanding of references) -[mutex_atomic](https://github.com/Manishearth/rust-clippy/wiki#mutex_atomic) | warn | using a Mutex where an atomic value could be used instead -[mutex_integer](https://github.com/Manishearth/rust-clippy/wiki#mutex_integer) | allow | using a Mutex for an integer type +[mut_mut](https://github.com/Manishearth/rust-clippy/wiki#mut_mut) | allow | usage of double-mut refs, e.g. `&mut &mut ...` +[mutex_atomic](https://github.com/Manishearth/rust-clippy/wiki#mutex_atomic) | warn | using a mutex where an atomic value could be used instead +[mutex_integer](https://github.com/Manishearth/rust-clippy/wiki#mutex_integer) | allow | using a mutex for an integer type [needless_bool](https://github.com/Manishearth/rust-clippy/wiki#needless_bool) | warn | if-statements with plain booleans in the then- and else-clause, e.g. `if p { true } else { false }` +[needless_borrow](https://github.com/Manishearth/rust-clippy/wiki#needless_borrow) | warn | taking a reference that is going to be automatically dereferenced [needless_lifetimes](https://github.com/Manishearth/rust-clippy/wiki#needless_lifetimes) | warn | using explicit lifetimes for references in function arguments when elision rules would allow omitting them [needless_range_loop](https://github.com/Manishearth/rust-clippy/wiki#needless_range_loop) | warn | for-looping over a range of indices where an iterator over items would do [needless_return](https://github.com/Manishearth/rust-clippy/wiki#needless_return) | warn | using a return statement like `return expr;` where an expression would suffice -[needless_update](https://github.com/Manishearth/rust-clippy/wiki#needless_update) | warn | using `{ ..base }` when there are no missing fields +[needless_update](https://github.com/Manishearth/rust-clippy/wiki#needless_update) | warn | using `Foo { ..base }` when there are no missing fields +[neg_multiply](https://github.com/Manishearth/rust-clippy/wiki#neg_multiply) | warn | Warns on multiplying integers with -1 [new_ret_no_self](https://github.com/Manishearth/rust-clippy/wiki#new_ret_no_self) | warn | not returning `Self` in a `new` method [new_without_default](https://github.com/Manishearth/rust-clippy/wiki#new_without_default) | warn | `fn new() -> Self` method without `Default` implementation +[new_without_default_derive](https://github.com/Manishearth/rust-clippy/wiki#new_without_default_derive) | warn | `fn new() -> Self` without `#[derive]`able `Default` implementation [no_effect](https://github.com/Manishearth/rust-clippy/wiki#no_effect) | warn | statements with no effect -[non_ascii_literal](https://github.com/Manishearth/rust-clippy/wiki#non_ascii_literal) | allow | using any literal non-ASCII chars in a string literal; suggests using the \\u escape instead +[non_ascii_literal](https://github.com/Manishearth/rust-clippy/wiki#non_ascii_literal) | allow | using any literal non-ASCII chars in a string literal; suggests using the `\\u` escape instead [nonminimal_bool](https://github.com/Manishearth/rust-clippy/wiki#nonminimal_bool) | allow | checks for boolean expressions that can be written more concisely [nonsensical_open_options](https://github.com/Manishearth/rust-clippy/wiki#nonsensical_open_options) | warn | nonsensical combination of options for opening a file +[not_unsafe_ptr_arg_deref](https://github.com/Manishearth/rust-clippy/wiki#not_unsafe_ptr_arg_deref) | warn | public functions dereferencing raw pointer arguments but not marked `unsafe` [ok_expect](https://github.com/Manishearth/rust-clippy/wiki#ok_expect) | warn | using `ok().expect()`, which gives worse error messages than calling `expect` directly on the Result [option_map_unwrap_or](https://github.com/Manishearth/rust-clippy/wiki#option_map_unwrap_or) | warn | using `Option.map(f).unwrap_or(a)`, which is more succinctly expressed as `map_or(a, f)` [option_map_unwrap_or_else](https://github.com/Manishearth/rust-clippy/wiki#option_map_unwrap_or_else) | warn | using `Option.map(f).unwrap_or_else(g)`, which is more succinctly expressed as `map_or_else(g, f)` @@ -109,7 +124,7 @@ name [out_of_bounds_indexing](https://github.com/Manishearth/rust-clippy/wiki#out_of_bounds_indexing) | deny | out of bound constant indexing [overflow_check_conditional](https://github.com/Manishearth/rust-clippy/wiki#overflow_check_conditional) | warn | Using overflow checks which are likely to panic [panic_params](https://github.com/Manishearth/rust-clippy/wiki#panic_params) | warn | missing parameters in `panic!` -[precedence](https://github.com/Manishearth/rust-clippy/wiki#precedence) | warn | catches operations where precedence may be unclear. See the wiki for a list of cases caught +[precedence](https://github.com/Manishearth/rust-clippy/wiki#precedence) | warn | catches operations where precedence may be unclear [print_stdout](https://github.com/Manishearth/rust-clippy/wiki#print_stdout) | allow | printing on stdout [ptr_arg](https://github.com/Manishearth/rust-clippy/wiki#ptr_arg) | warn | fn arguments of the type `&Vec<...>` or `&String`, suggesting to use `&[...]` or `&str` instead, respectively [range_step_by_zero](https://github.com/Manishearth/rust-clippy/wiki#range_step_by_zero) | warn | using Range::step_by(0), which produces an infinite iterator @@ -121,59 +136,75 @@ name [result_unwrap_used](https://github.com/Manishearth/rust-clippy/wiki#result_unwrap_used) | allow | using `Result.unwrap()`, which might be better handled [reverse_range_loop](https://github.com/Manishearth/rust-clippy/wiki#reverse_range_loop) | warn | Iterating over an empty range, such as `10..0` or `5..5` [search_is_some](https://github.com/Manishearth/rust-clippy/wiki#search_is_some) | warn | using an iterator search followed by `is_some()`, which is more succinctly expressed as a call to `any()` +[serde_api_misuse](https://github.com/Manishearth/rust-clippy/wiki#serde_api_misuse) | warn | Various things that will negatively affect your serde experience [shadow_reuse](https://github.com/Manishearth/rust-clippy/wiki#shadow_reuse) | allow | rebinding a name to an expression that re-uses the original value, e.g. `let x = x + 1` [shadow_same](https://github.com/Manishearth/rust-clippy/wiki#shadow_same) | allow | rebinding a name to itself, e.g. `let mut x = &mut x` [shadow_unrelated](https://github.com/Manishearth/rust-clippy/wiki#shadow_unrelated) | allow | The name is re-bound without even using the original value [should_implement_trait](https://github.com/Manishearth/rust-clippy/wiki#should_implement_trait) | warn | defining a method that should be implementing a std trait -[similar_names](https://github.com/Manishearth/rust-clippy/wiki#similar_names) | warn | similarly named items and bindings +[similar_names](https://github.com/Manishearth/rust-clippy/wiki#similar_names) | allow | similarly named items and bindings [single_char_pattern](https://github.com/Manishearth/rust-clippy/wiki#single_char_pattern) | warn | using a single-character str where a char could be used, e.g. `_.split("x")` [single_match](https://github.com/Manishearth/rust-clippy/wiki#single_match) | warn | a match statement with a single nontrivial arm (i.e, where the other arm is `_ => {}`) is used; recommends `if let` instead [single_match_else](https://github.com/Manishearth/rust-clippy/wiki#single_match_else) | allow | a match statement with a two arms where the second arm's pattern is a wildcard; recommends `if let` instead [string_add](https://github.com/Manishearth/rust-clippy/wiki#string_add) | allow | using `x + ..` where x is a `String`; suggests using `push_str()` instead [string_add_assign](https://github.com/Manishearth/rust-clippy/wiki#string_add_assign) | allow | using `x = x + ..` where x is a `String`; suggests using `push_str()` instead [string_lit_as_bytes](https://github.com/Manishearth/rust-clippy/wiki#string_lit_as_bytes) | warn | calling `as_bytes` on a string literal; suggests using a byte string literal instead +[stutter](https://github.com/Manishearth/rust-clippy/wiki#stutter) | allow | finds type names prefixed/postfixed with their containing module's name [suspicious_assignment_formatting](https://github.com/Manishearth/rust-clippy/wiki#suspicious_assignment_formatting) | warn | suspicious formatting of `*=`, `-=` or `!=` [suspicious_else_formatting](https://github.com/Manishearth/rust-clippy/wiki#suspicious_else_formatting) | warn | suspicious formatting of `else if` [temporary_assignment](https://github.com/Manishearth/rust-clippy/wiki#temporary_assignment) | warn | assignments to temporaries +[temporary_cstring_as_ptr](https://github.com/Manishearth/rust-clippy/wiki#temporary_cstring_as_ptr) | warn | getting the inner pointer of a temporary `CString` [too_many_arguments](https://github.com/Manishearth/rust-clippy/wiki#too_many_arguments) | warn | functions with too many arguments [toplevel_ref_arg](https://github.com/Manishearth/rust-clippy/wiki#toplevel_ref_arg) | warn | An entire binding was declared as `ref`, in a function argument (`fn foo(ref x: Bar)`), or a `let` statement (`let ref x = foo()`). In such cases, it is preferred to take references with `&`. [transmute_ptr_to_ref](https://github.com/Manishearth/rust-clippy/wiki#transmute_ptr_to_ref) | warn | transmutes from a pointer to a reference type -[trivial_regex](https://github.com/Manishearth/rust-clippy/wiki#trivial_regex) | warn | finds trivial regular expressions in `Regex::new(_)` invocations +[trivial_regex](https://github.com/Manishearth/rust-clippy/wiki#trivial_regex) | warn | finds trivial regular expressions [type_complexity](https://github.com/Manishearth/rust-clippy/wiki#type_complexity) | warn | usage of very complex types; recommends factoring out parts into `type` definitions -[unicode_not_nfc](https://github.com/Manishearth/rust-clippy/wiki#unicode_not_nfc) | allow | using a unicode literal not in NFC normal form (see http://www.unicode.org/reports/tr15/ for further information) +[unicode_not_nfc](https://github.com/Manishearth/rust-clippy/wiki#unicode_not_nfc) | allow | using a unicode literal not in NFC normal form (see [unicode tr15](http://www.unicode.org/reports/tr15/) for further information) [unit_cmp](https://github.com/Manishearth/rust-clippy/wiki#unit_cmp) | warn | comparing unit values (which is always `true` or `false`, respectively) [unnecessary_mut_passed](https://github.com/Manishearth/rust-clippy/wiki#unnecessary_mut_passed) | warn | an argument is passed as a mutable reference although the function/method only demands an immutable reference +[unnecessary_operation](https://github.com/Manishearth/rust-clippy/wiki#unnecessary_operation) | warn | outer expressions with no effect [unneeded_field_pattern](https://github.com/Manishearth/rust-clippy/wiki#unneeded_field_pattern) | warn | Struct fields are bound to a wildcard instead of using `..` +[unsafe_removed_from_name](https://github.com/Manishearth/rust-clippy/wiki#unsafe_removed_from_name) | warn | unsafe removed from name [unused_collect](https://github.com/Manishearth/rust-clippy/wiki#unused_collect) | warn | `collect()`ing an iterator without using the result; this is usually better written as a for loop [unused_label](https://github.com/Manishearth/rust-clippy/wiki#unused_label) | warn | unused label [unused_lifetimes](https://github.com/Manishearth/rust-clippy/wiki#unused_lifetimes) | warn | unused lifetimes in function definitions [use_debug](https://github.com/Manishearth/rust-clippy/wiki#use_debug) | allow | use `Debug`-based formatting -[used_underscore_binding](https://github.com/Manishearth/rust-clippy/wiki#used_underscore_binding) | warn | using a binding which is prefixed with an underscore +[used_underscore_binding](https://github.com/Manishearth/rust-clippy/wiki#used_underscore_binding) | allow | using a binding which is prefixed with an underscore [useless_format](https://github.com/Manishearth/rust-clippy/wiki#useless_format) | warn | useless use of `format!` -[useless_transmute](https://github.com/Manishearth/rust-clippy/wiki#useless_transmute) | warn | transmutes that have the same to and from types +[useless_let_if_seq](https://github.com/Manishearth/rust-clippy/wiki#useless_let_if_seq) | warn | Checks for unidiomatic `let mut` declaration followed by initialization in `if` +[useless_transmute](https://github.com/Manishearth/rust-clippy/wiki#useless_transmute) | warn | transmutes that have the same to and from types or could be a cast/coercion [useless_vec](https://github.com/Manishearth/rust-clippy/wiki#useless_vec) | warn | useless `vec!` [while_let_loop](https://github.com/Manishearth/rust-clippy/wiki#while_let_loop) | warn | `loop { if let { ... } else break }` can be written as a `while let` loop [while_let_on_iterator](https://github.com/Manishearth/rust-clippy/wiki#while_let_on_iterator) | warn | using a while-let loop instead of a for loop on an iterator [wrong_pub_self_convention](https://github.com/Manishearth/rust-clippy/wiki#wrong_pub_self_convention) | allow | defining a public method named with an established prefix (like "into_") that takes `self` with the wrong convention [wrong_self_convention](https://github.com/Manishearth/rust-clippy/wiki#wrong_self_convention) | warn | defining a method named with an established prefix (like "into_") that takes `self` with the wrong convention +[wrong_transmute](https://github.com/Manishearth/rust-clippy/wiki#wrong_transmute) | warn | transmutes that are confusing at best, undefined behaviour at worst and always useless [zero_divided_by_zero](https://github.com/Manishearth/rust-clippy/wiki#zero_divided_by_zero) | warn | usage of `0.0 / 0.0` to obtain NaN instead of std::f32::NaN or std::f64::NaN [zero_width_space](https://github.com/Manishearth/rust-clippy/wiki#zero_width_space) | deny | using a zero-width space in a string literal, which is confusing More to come, please [file an issue](https://github.com/Manishearth/rust-clippy/issues) if you have ideas! -##Usage +## Usage + +As a general rule clippy will only work with the *latest* Rust nightly for now. -Compiler plugins are highly unstable and will only work with a nightly Rust for now. Since stable Rust is backwards compatible, you should be able to compile your stable programs with nightly Rust with clippy plugged in to circumvent this. +### As a Compiler Plugin + +Since stable Rust is backwards compatible, you should be able to +compile your stable programs with nightly Rust with clippy plugged in to +circumvent this. Add in your `Cargo.toml`: + ```toml [dependencies] clippy = "*" ``` -You then need to add `#![feature(plugin)]` and `#![plugin(clippy)]` to the top of your crate entry point (`main.rs` or `lib.rs`). +You then need to add `#![feature(plugin)]` and `#![plugin(clippy)]` to the top +of your crate entry point (`main.rs` or `lib.rs`). Sample `main.rs`: + ```rust #![feature(plugin)] @@ -190,7 +221,8 @@ fn main(){ ``` Produces this warning: -``` + +```terminal src/main.rs:8:5: 11:6 warning: you seem to be trying to use match for destructuring a single type. Consider using `if let`, #[warn(single_match)] on by default src/main.rs:8 match x { src/main.rs:9 Some(y) => println!("{:?}", y), @@ -200,35 +232,51 @@ src/main.rs:8:5: 11:6 help: Try if let Some(y) = x { println!("{:?}", y) } ``` +### As a cargo subcommand (`cargo clippy`) -An alternate way to use clippy is by compiling and using [`cargo clippy`](https://github.com/arcnmx/cargo-clippy), a custom cargo subcommand that runs clippy on a given project. +An alternate way to use clippy is by installing clippy through cargo as a cargo +subcommand. -You can add options to `allow`/`warn`/`deny`: -- the whole set of `Warn` lints using the `clippy` lint group (`#![deny(clippy)]`) -- all lints using both the `clippy` and `clippy_pedantic` lint groups (`#![deny(clippy)]`, `#![deny(clippy_pedantic)]`). Note that `clippy_pedantic` contains some very aggressive lints prone to false positives. -- only some lints (`#![deny(single_match, box_vec)]`, etc) -- `allow`/`warn`/`deny` can be limited to a single function or module using `#[allow(...)]`, etc +```terminal +cargo install clippy +``` + +Now you can run clippy by invoking `cargo clippy`, or +`multirust run nightly cargo clippy` directly from a directory that is usually +compiled with stable. -Note: `deny` produces errors instead of warnings +In case you are not using multirust, you need to set the environment flag +`SYSROOT` during installation so clippy knows where to find `librustc` and +similar crates. + +```terminal +SYSROOT=/path/to/rustc/sysroot cargo install clippy +``` + +### Running clippy from the command line without installing To have cargo compile your crate with clippy without needing `#![plugin(clippy)]` in your code, you can use: -``` +```terminal cargo rustc -- -L /path/to/clippy_so -Z extra-plugins=clippy ``` -*[Note](https://github.com/Manishearth/rust-clippy/wiki#a-word-of-warning):* Be sure that clippy was compiled with the same version of rustc that cargo invokes here! +*[Note](https://github.com/Manishearth/rust-clippy/wiki#a-word-of-warning):* +Be sure that clippy was compiled with the same version of rustc that cargo invokes here! + +### Optional dependency If you want to make clippy an optional dependency, you can do the following: In your `Cargo.toml`: + ```toml [dependencies] clippy = {version = "*", optional = true} [features] -default=[] +default = [] ``` And, in your `main.rs` or `lib.rs`: @@ -239,9 +287,15 @@ And, in your `main.rs` or `lib.rs`: #![cfg_attr(feature="clippy", plugin(clippy))] ``` -Instead of adding the `cfg_attr` attributes you can also run clippy on demand: `cargo rustc --features clippy -- -Z no-trans -Z extra-plugins=clippy` (the `-Z no trans`, while not neccessary, will stop the compilation process after typechecking (and lints) have completed, which can significantly reduce the runtime). +Then build by enabling the feature: `cargo build --features "clippy"` + +Instead of adding the `cfg_attr` attributes you can also run clippy on demand: +`cargo rustc --features clippy -- -Z no-trans -Z extra-plugins=clippy` +(the `-Z no trans`, while not neccessary, will stop the compilation process after +typechecking (and lints) have completed, which can significantly reduce the runtime). ## Configuration + Some lints can be configured in a `clippy.toml` file. It contains basic `variable = value` mapping eg. ```toml @@ -253,16 +307,40 @@ See the wiki for more information about which lints can be configured and the meaning of the variables. You can also specify the path to the configuration file with: + ```rust #![plugin(clippy(conf_file="path/to/clippy's/configuration"))] ``` -##Link with clippy service +To deactivate the “for further information visit *wiki-link*” message you can +define the `CLIPPY_DISABLE_WIKI_LINKS` environment variable. + +### Allowing/denying lints + +You can add options to `allow`/`warn`/`deny`: + +* the whole set of `Warn` lints using the `clippy` lint group (`#![deny(clippy)]`) + +* all lints using both the `clippy` and `clippy_pedantic` lint groups (`#![deny(clippy)]`, + `#![deny(clippy_pedantic)]`). Note that `clippy_pedantic` contains some very aggressive + lints prone to false positives. + +* only some lints (`#![deny(single_match, box_vec)]`, etc) + +* `allow`/`warn`/`deny` can be limited to a single function or module using `#[allow(...)]`, etc + +Note: `deny` produces errors instead of warnings. + +## Link with clippy service + `clippy-service` is a rust web initiative providing `rust-clippy` as a web service. -Both projects are independent and maintained by different people (even if some `clippy-service`'s contributions are authored by some `rust-clippy` members). +Both projects are independent and maintained by different people +(even if some `clippy-service`'s contributions are authored by some `rust-clippy` members). + +You can check out this great service at [clippy.bashy.io](https://clippy.bashy.io/). -You can check it out this great service at [clippy.bashy.io](https://clippy.bashy.io/). +## License -##License -Licensed under [MPL](https://www.mozilla.org/MPL/2.0/). If you're having issues with the license, let me know and I'll try to change it to something more permissive. +Licensed under [MPL](https://www.mozilla.org/MPL/2.0/). +If you're having issues with the license, let me know and I'll try to change it to something more permissive.