| commit | fc09eb553e6097c37bc442ceee0a0223bbce2513 | [log] [tgz] |
|---|---|---|
| author | mcarton <cartonmartin+git@gmail.com> | Thu Oct 06 17:50:11 2016 +0200 |
| committer | mcarton <cartonmartin+git@gmail.com> | Thu Oct 06 17:50:11 2016 +0200 |
| tree | 0fdf45a3ccf726fa9e6cf1e45f4f499cbc817f7e | |
| parent | 0475eae1fa518dbd2f11f870b69507fe13dabe41 [diff] |
Fix dogfood problem
A collection of lints to catch common mistakes and improve your Rust code.
Table of contents:
As a general rule clippy will only work with the latest Rust nightly 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.
Add in your Cargo.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).
Sample main.rs:
#![feature(plugin)] #![plugin(clippy)] fn main(){ let x = Some(1u8); match x { Some(y) => println!("{:?}", y), _ => () } }
Produces this warning:
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), src/main.rs:10 _ => () src/main.rs:11 } src/main.rs:8:5: 11:6 help: Try if let Some(y) = x { println!("{:?}", y) }
cargo clippy)An alternate way to use clippy is by installing clippy through cargo as a cargo subcommand.
cargo install clippy
Now you can run clippy by invoking cargo clippy, or rustup run nightly cargo clippy directly from a directory that is usually compiled with stable.
In case you are not using rustup, you need to set the environment flag SYSROOT during installation so clippy knows where to find librustc and similar crates.
SYSROOT=/path/to/rustc/sysroot cargo install clippy
To have cargo compile your crate with clippy without needing #![plugin(clippy)] in your code, you can use:
cargo rustc -- -L /path/to/clippy_so -Z extra-plugins=clippy
Note: Be sure that clippy was compiled with the same version of rustc that cargo invokes here!
If you want to make clippy an optional dependency, you can do the following:
In your Cargo.toml:
[dependencies] clippy = {version = "*", optional = true} [features] default = []
And, in your main.rs or lib.rs:
#![cfg_attr(feature="clippy", feature(plugin))] #![cfg_attr(feature="clippy", plugin(clippy))]
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).
Some lints can be configured in a clippy.toml file. It contains basic variable = value mapping eg.
blacklisted-names = ["toto", "tata", "titi"] cyclomatic-complexity-threshold = 30
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:
#![plugin(clippy(conf_file="path/to/clippy's/configuration"))]
To deactivate the “for further information visit wiki-link” message you can define the CLIPPY_DISABLE_WIKI_LINKS environment variable.
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.
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).
You can check out this great service at clippy.bashy.io.
There are 173 lints included in this crate:
| name | default | triggers on |
|---|---|---|
| absurd_extreme_comparisons | warn | a comparison with a maximum or minimum value that is always true or false |
| almost_swapped | warn | foo = bar; bar = foo sequence |
| approx_constant | warn | the approximate of a known float constant (in std::fXX::consts) |
| assign_op_pattern | warn | assigning the result of an operation on a variable to that same variable |
| assign_ops | allow | any compound assignment operation |
| bad_bit_mask | warn | expressions of the form _ & mask == select that will only ever return true or false |
| blacklisted_name | warn | usage of a blacklisted/placeholder name |
| block_in_if_condition_expr | warn | braces that can be eliminated in conditions, e.g if { true } ... |
| block_in_if_condition_stmt | warn | complex blocks in conditions, e.g. if { let x = true; x } ... |
| bool_comparison | warn | comparing a variable to a boolean, e.g. if x == true |
| box_vec | warn | usage of Box<Vec<T>>, vector elements are already on the heap |
| boxed_local | warn | using Box<T> where unnecessary |
| builtin_type_shadow | warn | shadowing a builtin type |
| 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 | allow | casts that may cause wrapping around the value, e.g x as i32 where x: u32 and x > i32::MAX |
| cast_precision_loss | allow | casts that cause loss of precision, e.g x as f32 where x: u64 |
| cast_sign_loss | allow | casts from signed types to unsigned types, e.g x as u32 where x: i32 |
| char_lit_as_u8 | warn | casting a character literal to u8 |
| chars_next_cmp | warn | using .chars().next() to check if a string starts with a char |
| clone_double_ref | warn | using clone on &&T |
| clone_on_copy | warn | using clone on a Copy type |
| cmp_nan | deny | comparisons to NAN, which will always return false, probably not intended |
| cmp_null | warn | comparing a pointer to a null pointer, suggesting to use .is_null() instead. |
| cmp_owned | warn | creating owned instances for comparing with others, e.g. x == "foo".to_string() |
| collapsible_if | warn | ifs that can be collapsed (e.g. if x { if y { ... } } and else { if x { ... } }) |
| crosspointer_transmute | warn | transmutes that have to or from types that are a pointer to the other |
| cyclomatic_complexity | warn | functions that should be split up into multiple functions |
| deprecated_semver | warn | use of #[deprecated(since = "x")] where x is not semver |
| derive_hash_xor_eq | warn | deriving Hash but implementing PartialEq explicitly |
| diverging_sub_expression | warn | whether an expression contains a diverging sub expression |
| doc_markdown | warn | presence of _, :: or camel-case outside backticks in documentation |
| double_neg | warn | --x, which is a double negation of x and not a pre-decrement as in C/C++ |
| drop_ref | warn | calls to std::mem::drop with a reference instead of an owned value |
| duplicate_underscore_argument | warn | function arguments having names which only differ by an underscore |
| empty_loop | warn | empty loop {}, which should block or sleep |
| enum_clike_unportable_variant | warn | C-like enums that are repr(isize/usize) and have values that don't fit into an i32 |
| enum_glob_use | allow | use items that import all variants of an enum |
| enum_variant_names | warn | enums where all variants share a prefix/postfix |
| eq_op | warn | equal operands on both sides of a comparison or bitwise combination (e.g. x == x) |
| eval_order_dependence | warn | whether a variable read occurs before a write depends on sub-expression evaluation order |
| expl_impl_clone_on_copy | warn | implementing Clone explicitly on Copy types |
| explicit_counter_loop | warn | for-looping with an explicit counter when _.enumerate() would do |
| explicit_into_iter_loop | warn | for-looping over _.into_iter() when _ would do |
| explicit_iter_loop | warn | for-looping over _.iter() or _.iter_mut() when &_ or &mut _ would do |
| extend_from_slice | warn | .extend_from_slice(_) is a faster way to extend a Vec by a slice |
| 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 | warn | using filter(p).next(), which is more succinctly expressed as .find(p) |
| float_arithmetic | allow | any floating-point arithmetic statement |
| float_cmp | warn | using == or != on float values instead of comparing difference with an epsilon |
| for_kv_map | warn | looping on a map using iter when keys or values would do |
| for_loop_over_option | warn | for-looping over an Option, which is more clearly expressed as an if let |
| for_loop_over_result | warn | for-looping over a Result, which is more clearly expressed as an if let |
| identity_op | warn | using identity operations, e.g. x + 0 or y / 1 |
| if_let_some_result | warn | usage of ok() in if let Some(pat) statements is unnecessary, match on Ok(pat) instead |
| if_not_else | allow | if branches that could be swapped so no negation operation is necessary on the condition |
| if_same_then_else | warn | if with the same then and else blocks |
| ifs_same_cond | warn | consecutive ifs with the same condition |
| indexing_slicing | allow | indexing/slicing usage |
| ineffective_bit_mask | warn | expressions where a bit mask will be rendered useless by a comparison, e.g. `(x |
| inline_always | warn | use of #[inline(always)] |
| integer_arithmetic | allow | any integer arithmetic statement |
| invalid_regex | deny | invalid regular expressions |
| invalid_upcast_comparisons | allow | a comparison involving an upcast which is always true or false |
| items_after_statements | allow | blocks where an item comes after a statement |
| iter_next_loop | warn | for-looping over _.next() which is probably not intended |
| iter_nth | warn | using .iter().nth() on a standard library type with O(1) element access |
| len_without_is_empty | warn | traits or impls with a public len method but no corresponding is_empty method |
| len_zero | warn | checking .len() == 0 or .len() > 0 (or similar) when .is_empty() could be used instead |
| let_and_return | warn | creating a let-binding and then immediately returning it like let x = expr; x at the end of a block |
| let_unit_value | warn | creating a let binding to a value of unit type, which usually can't be used afterwards |
| linkedlist | warn | usage of LinkedList, usually a vector is faster, or a more specialized data structure like a VecDeque |
| logic_bug | warn | boolean expressions that contain terminals which can be eliminated |
| manual_swap | warn | manual swap of two variables |
| many_single_char_names | warn | too many single character bindings |
| map_clone | warn | using `.map( |
| map_entry | warn | use of contains_key followed by insert on a HashMap or BTreeMap |
| match_bool | warn | a match on a boolean expression instead of an if..else block |
| match_overlapping_arm | warn | a match with overlapping arms |
| match_ref_pats | warn | a match or if let with all arms prefixed with & instead of deref-ing the match expression |
| match_same_arms | warn | match with identical arm bodies |
| mem_forget | allow | mem::forget usage on Drop types, likely to cause memory leaks |
| min_max | warn | min(_, max(_, _)) (or vice versa) with bounds clamping the result to a constant |
| misrefactored_assign_op | warn | having a variable on both sides of an assign op |
| missing_docs_in_private_items | allow | detects missing documentation for public and private members |
| mixed_case_hex_literals | warn | hex literals whose letter digits are not consistently upper- or lowercased |
| module_inception | warn | modules that have the same name as their parent module |
| modulo_one | warn | taking a number modulo 1, which always returns 0 |
| mut_mut | allow | usage of double-mut refs, e.g. &mut &mut ... |
| mutex_atomic | warn | using a mutex where an atomic value could be used instead |
| mutex_integer | allow | using a mutex for an integer type |
| needless_bool | warn | if-statements with plain booleans in the then- and else-clause, e.g. if p { true } else { false } |
| needless_borrow | warn | taking a reference that is going to be automatically dereferenced |
| needless_lifetimes | warn | using explicit lifetimes for references in function arguments when elision rules would allow omitting them |
| needless_range_loop | warn | for-looping over a range of indices where an iterator over items would do |
| needless_return | warn | using a return statement like return expr; where an expression would suffice |
| needless_update | warn | using Foo { ..base } when there are no missing fields |
| neg_multiply | warn | multiplying integers with -1 |
| new_ret_no_self | warn | not returning Self in a new method |
| new_without_default | warn | fn new() -> Self method without Default implementation |
| new_without_default_derive | warn | fn new() -> Self without #[derive]able Default implementation |
| no_effect | warn | statements with no effect |
| non_ascii_literal | allow | using any literal non-ASCII chars in a string literal instead of using the \\u escape |
| nonminimal_bool | allow | boolean expressions that can be written more concisely |
| nonsensical_open_options | warn | nonsensical combination of options for opening a file |
| not_unsafe_ptr_arg_deref | warn | public functions dereferencing raw pointer arguments but not marked unsafe |
| ok_expect | warn | using ok().expect(), which gives worse error messages than calling expect directly on the Result |
| option_map_unwrap_or | allow | using Option.map(f).unwrap_or(a), which is more succinctly expressed as map_or(a, f) |
| option_map_unwrap_or_else | allow | using Option.map(f).unwrap_or_else(g), which is more succinctly expressed as map_or_else(g, f) |
| option_unwrap_used | allow | using Option.unwrap(), which should at least get a better message using expect() |
| or_fun_call | warn | using any *or method with a function call, which suggests *or_else |
| out_of_bounds_indexing | deny | out of bounds constant indexing |
| overflow_check_conditional | warn | overflow checks inspired by C which are likely to panic |
| panic_params | warn | missing parameters in panic! calls |
| precedence | warn | operations where precedence may be unclear |
| print_stdout | allow | printing on stdout |
| print_with_newline | warn | using print!() with a format string that ends in a newline |
| ptr_arg | warn | fn arguments of the type &Vec<...> or &String, suggesting to use &[...] or &str instead, respectively |
| range_step_by_zero | warn | using Range::step_by(0), which produces an infinite iterator |
| range_zip_with_len | warn | zipping iterator with a range when enumerate() would do |
| redundant_closure | warn | redundant closures, i.e. ` |
| redundant_closure_call | warn | throwaway closures called in the expression they are defined |
| redundant_pattern | warn | using name @ _ in a pattern |
| regex_macro | warn | use of regex!(_) instead of Regex::new(_) |
| result_unwrap_used | allow | using Result.unwrap(), which might be better handled |
| reverse_range_loop | warn | iteration over an empty range, such as 10..0 or 5..5 |
| 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 | warn | various things that will negatively affect your serde experience |
| shadow_reuse | allow | rebinding a name to an expression that re-uses the original value, e.g. let x = x + 1 |
| shadow_same | allow | rebinding a name to itself, e.g. let mut x = &mut x |
| shadow_unrelated | allow | rebinding a name without even using the original value |
| should_implement_trait | warn | defining a method that should be implementing a std trait |
| similar_names | allow | similarly named items and bindings |
| single_char_pattern | warn | using a single-character str where a char could be used, e.g. _.split("x") |
| single_match | warn | a match statement with a single nontrivial arm (i.e, where the other arm is _ => {}) instead of if let |
| single_match_else | allow | a match statement with a two arms where the second arm's pattern is a wildcard instead of if let |
| string_add | allow | using x + .. where x is a String instead of push_str() |
| string_add_assign | allow | using x = x + .. where x is a String instead of push_str() |
| string_lit_as_bytes | warn | calling as_bytes on a string literal instead of using a byte string literal |
| stutter | allow | type names prefixed/postfixed with their containing module's name |
| suspicious_assignment_formatting | warn | suspicious formatting of *=, -= or != |
| suspicious_else_formatting | warn | suspicious formatting of else if |
| temporary_assignment | warn | assignments to temporaries |
| temporary_cstring_as_ptr | warn | getting the inner pointer of a temporary CString |
| too_many_arguments | warn | functions with too many arguments |
| toplevel_ref_arg | warn | an entire binding declared as ref, in a function argument or a let statement |
| transmute_ptr_to_ref | warn | transmutes from a pointer to a reference type |
| trivial_regex | warn | trivial regular expressions |
| type_complexity | warn | usage of very complex types that might be better factored into type definitions |
| unicode_not_nfc | allow | using a unicode literal not in NFC normal form (see unicode tr15 for further information) |
| unit_cmp | warn | comparing unit values |
| unnecessary_mut_passed | warn | an argument passed as a mutable reference although the callee only demands an immutable reference |
| unnecessary_operation | warn | outer expressions with no effect |
| unneeded_field_pattern | warn | struct fields bound to a wildcard instead of using .. |
| unsafe_removed_from_name | warn | unsafe removed from API names on import |
| unseparated_literal_suffix | allow | literals whose suffix is not separated by an underscore |
| unused_collect | warn | collect()ing an iterator without using the result; this is usually better written as a for loop |
| unused_label | warn | unused labels |
| unused_lifetimes | warn | unused lifetimes in function definitions |
| use_debug | allow | use of Debug-based formatting |
| used_underscore_binding | allow | using a binding which is prefixed with an underscore |
| useless_attribute | warn | use of lint attributes on extern crate items |
| useless_format | warn | useless use of format! |
| useless_let_if_seq | warn | unidiomatic let mut declaration followed by initialization in if |
| useless_transmute | warn | transmutes that have the same to and from types or could be a cast/coercion |
| useless_vec | warn | useless vec! |
| while_let_loop | warn | loop { if let { ... } else break }, which can be written as a while let loop |
| while_let_on_iterator | warn | using a while-let loop instead of a for loop on an iterator |
| 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 | warn | defining a method named with an established prefix (like “into_”) that takes self with the wrong convention |
| wrong_transmute | warn | transmutes that are confusing at best, undefined behaviour at worst and always useless |
| zero_divided_by_zero | warn | usage of 0.0 / 0.0 to obtain NaN instead of std::f32::NaN or std::f64::NaN |
| zero_prefixed_literal | warn | integer literals starting with 0 |
| zero_width_space | deny | using a zero-width space in a string literal, which is confusing |
More to come, please file an issue if you have ideas!
Licensed under MPL. If you‘re having issues with the license, let me know and I’ll try to change it to something more permissive.