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Add lint for redundant pattern matching in iflet for Result/Option

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d-dorazio 2016-10-29 18:56:12 +02:00
parent 502416fa78
commit d213040381
13 changed files with 339 additions and 186 deletions
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1
CHANGELOG.md
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@ -257,6 +257,7 @@ All notable changes to this project will be documented in this file.
[`for_loop_over_option`]: https://github.com/Manishearth/rust-clippy/wiki#for_loop_over_option [`for_loop_over_option`]: https://github.com/Manishearth/rust-clippy/wiki#for_loop_over_option
[`for_loop_over_result`]: https://github.com/Manishearth/rust-clippy/wiki#for_loop_over_result [`for_loop_over_result`]: https://github.com/Manishearth/rust-clippy/wiki#for_loop_over_result
[`identity_op`]: https://github.com/Manishearth/rust-clippy/wiki#identity_op [`identity_op`]: https://github.com/Manishearth/rust-clippy/wiki#identity_op
[`if_let_redundant_pattern_matching`]: https://github.com/Manishearth/rust-clippy/wiki#if_let_redundant_pattern_matching
[`if_let_some_result`]: https://github.com/Manishearth/rust-clippy/wiki#if_let_some_result [`if_let_some_result`]: https://github.com/Manishearth/rust-clippy/wiki#if_let_some_result
[`if_not_else`]: https://github.com/Manishearth/rust-clippy/wiki#if_not_else [`if_not_else`]: https://github.com/Manishearth/rust-clippy/wiki#if_not_else
[`if_same_then_else`]: https://github.com/Manishearth/rust-clippy/wiki#if_same_then_else [`if_same_then_else`]: https://github.com/Manishearth/rust-clippy/wiki#if_same_then_else

355
README.md
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@ -174,184 +174,185 @@ You can check out this great service at [clippy.bashy.io](https://clippy.bashy.i
## Lints ## Lints
There are 174 lints included in this crate: There are 175 lints included in this crate:
name | default | triggers on name | default | triggers on
---------------------------------------------------------------------------------------------------------------------|---------|---------------------------------------------------------------------------------------------------------------------------------- -----------------------------------------------------------------------------------------------------------------------|---------|----------------------------------------------------------------------------------------------------------------------------------
[absurd_extreme_comparisons](https://github.com/Manishearth/rust-clippy/wiki#absurd_extreme_comparisons) | warn | a comparison with a maximum or minimum value that is always true or false [absurd_extreme_comparisons](https://github.com/Manishearth/rust-clippy/wiki#absurd_extreme_comparisons) | warn | a comparison with a maximum or minimum value that is always true or false
[almost_swapped](https://github.com/Manishearth/rust-clippy/wiki#almost_swapped) | warn | `foo = bar; bar = foo` sequence [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::fXX::consts`) [approx_constant](https://github.com/Manishearth/rust-clippy/wiki#approx_constant) | warn | the approximate of a known float constant (in `std::fXX::consts`)
[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_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 compound assignment operation [assign_ops](https://github.com/Manishearth/rust-clippy/wiki#assign_ops) | allow | any compound 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` [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`
[blacklisted_name](https://github.com/Manishearth/rust-clippy/wiki#blacklisted_name) | warn | usage of a blacklisted/placeholder name [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 that can be eliminated in conditions, e.g `if { true } ...` [block_in_if_condition_expr](https://github.com/Manishearth/rust-clippy/wiki#block_in_if_condition_expr) | warn | braces that can be eliminated in conditions, e.g `if { true } ...`
[block_in_if_condition_stmt](https://github.com/Manishearth/rust-clippy/wiki#block_in_if_condition_stmt) | warn | complex blocks in conditions, e.g. `if { let x = true; x } ...` [block_in_if_condition_stmt](https://github.com/Manishearth/rust-clippy/wiki#block_in_if_condition_stmt) | warn | complex blocks in conditions, 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` [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<Vec<T>>`, vector elements are already on the heap [box_vec](https://github.com/Manishearth/rust-clippy/wiki#box_vec) | warn | usage of `Box<Vec<T>>`, vector elements are already on the heap
[boxed_local](https://github.com/Manishearth/rust-clippy/wiki#boxed_local) | warn | using `Box<T>` where unnecessary [boxed_local](https://github.com/Manishearth/rust-clippy/wiki#boxed_local) | warn | using `Box<T>` where unnecessary
[builtin_type_shadow](https://github.com/Manishearth/rust-clippy/wiki#builtin_type_shadow) | warn | shadowing a builtin type [builtin_type_shadow](https://github.com/Manishearth/rust-clippy/wiki#builtin_type_shadow) | warn | shadowing a builtin type
[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_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_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` [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`
[cast_sign_loss](https://github.com/Manishearth/rust-clippy/wiki#cast_sign_loss) | allow | casts from signed types to unsigned types, e.g `x as u32` where `x: i32` [cast_sign_loss](https://github.com/Manishearth/rust-clippy/wiki#cast_sign_loss) | allow | casts from signed types to unsigned types, e.g `x as u32` where `x: i32`
[char_lit_as_u8](https://github.com/Manishearth/rust-clippy/wiki#char_lit_as_u8) | warn | casting a character literal to u8 [char_lit_as_u8](https://github.com/Manishearth/rust-clippy/wiki#char_lit_as_u8) | warn | casting a character literal to u8
[chars_next_cmp](https://github.com/Manishearth/rust-clippy/wiki#chars_next_cmp) | warn | using `.chars().next()` to check if a string starts with a char [chars_next_cmp](https://github.com/Manishearth/rust-clippy/wiki#chars_next_cmp) | warn | using `.chars().next()` to check if a string starts with a char
[clone_double_ref](https://github.com/Manishearth/rust-clippy/wiki#clone_double_ref) | warn | using `clone` on `&&T` [clone_double_ref](https://github.com/Manishearth/rust-clippy/wiki#clone_double_ref) | warn | using `clone` on `&&T`
[clone_on_copy](https://github.com/Manishearth/rust-clippy/wiki#clone_on_copy) | warn | using `clone` on a `Copy` type [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, probably not intended [cmp_nan](https://github.com/Manishearth/rust-clippy/wiki#cmp_nan) | deny | comparisons to NAN, which will always return false, probably not intended
[cmp_null](https://github.com/Manishearth/rust-clippy/wiki#cmp_null) | warn | comparing a pointer to a null pointer, suggesting to use `.is_null()` instead. [cmp_null](https://github.com/Manishearth/rust-clippy/wiki#cmp_null) | warn | comparing a pointer to a null pointer, suggesting to use `.is_null()` instead.
[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()` [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 | `if`s that can be collapsed (e.g. `if x { if y { ... } }` and `else { if x { ... } }`) [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 [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 | functions that should be split up into multiple functions [cyclomatic_complexity](https://github.com/Manishearth/rust-clippy/wiki#cyclomatic_complexity) | warn | functions that should be split up into multiple functions
[deprecated_semver](https://github.com/Manishearth/rust-clippy/wiki#deprecated_semver) | warn | use of `#[deprecated(since = "x")]` where x is not semver [deprecated_semver](https://github.com/Manishearth/rust-clippy/wiki#deprecated_semver) | warn | use of `#[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 [derive_hash_xor_eq](https://github.com/Manishearth/rust-clippy/wiki#derive_hash_xor_eq) | warn | deriving `Hash` but implementing `PartialEq` explicitly
[diverging_sub_expression](https://github.com/Manishearth/rust-clippy/wiki#diverging_sub_expression) | warn | whether an expression contains a diverging sub expression [diverging_sub_expression](https://github.com/Manishearth/rust-clippy/wiki#diverging_sub_expression) | warn | whether an expression contains a diverging sub expression
[doc_markdown](https://github.com/Manishearth/rust-clippy/wiki#doc_markdown) | warn | presence of `_`, `::` or camel-case outside backticks in documentation [doc_markdown](https://github.com/Manishearth/rust-clippy/wiki#doc_markdown) | warn | presence of `_`, `::` or camel-case outside backticks in documentation
[double_neg](https://github.com/Manishearth/rust-clippy/wiki#double_neg) | warn | `--x`, which is a double negation of `x` and not a pre-decrement as in C/C++ [double_neg](https://github.com/Manishearth/rust-clippy/wiki#double_neg) | warn | `--x`, which is a double negation of `x` and not a pre-decrement as in C/C++
[drop_ref](https://github.com/Manishearth/rust-clippy/wiki#drop_ref) | warn | calls to `std::mem::drop` with a reference instead of an owned value [drop_ref](https://github.com/Manishearth/rust-clippy/wiki#drop_ref) | warn | calls to `std::mem::drop` with a reference instead of an owned 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 [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 {}`, which should block or sleep [empty_loop](https://github.com/Manishearth/rust-clippy/wiki#empty_loop) | warn | empty `loop {}`, which should block or sleep
[enum_clike_unportable_variant](https://github.com/Manishearth/rust-clippy/wiki#enum_clike_unportable_variant) | warn | C-like enums that are `repr(isize/usize)` and have values that don't fit into an `i32` [enum_clike_unportable_variant](https://github.com/Manishearth/rust-clippy/wiki#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](https://github.com/Manishearth/rust-clippy/wiki#enum_glob_use) | allow | use items that import all variants of an enum [enum_glob_use](https://github.com/Manishearth/rust-clippy/wiki#enum_glob_use) | allow | use items that import all variants of an enum
[enum_variant_names](https://github.com/Manishearth/rust-clippy/wiki#enum_variant_names) | warn | enums where all variants share a prefix/postfix [enum_variant_names](https://github.com/Manishearth/rust-clippy/wiki#enum_variant_names) | warn | enums where all variants share a prefix/postfix
[eq_op](https://github.com/Manishearth/rust-clippy/wiki#eq_op) | warn | equal operands on both sides of a comparison or bitwise combination (e.g. `x == x`) [eq_op](https://github.com/Manishearth/rust-clippy/wiki#eq_op) | warn | equal operands on both sides of a comparison or bitwise combination (e.g. `x == x`)
[eval_order_dependence](https://github.com/Manishearth/rust-clippy/wiki#eval_order_dependence) | warn | whether a variable read occurs before a write depends on sub-expression evaluation order [eval_order_dependence](https://github.com/Manishearth/rust-clippy/wiki#eval_order_dependence) | warn | whether a variable read occurs before a write depends on sub-expression evaluation order
[expl_impl_clone_on_copy](https://github.com/Manishearth/rust-clippy/wiki#expl_impl_clone_on_copy) | warn | implementing `Clone` explicitly on `Copy` types [expl_impl_clone_on_copy](https://github.com/Manishearth/rust-clippy/wiki#expl_impl_clone_on_copy) | warn | implementing `Clone` explicitly on `Copy` types
[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_counter_loop](https://github.com/Manishearth/rust-clippy/wiki#explicit_counter_loop) | warn | for-looping with an explicit counter when `_.enumerate()` would do
[explicit_into_iter_loop](https://github.com/Manishearth/rust-clippy/wiki#explicit_into_iter_loop) | warn | for-looping over `_.into_iter()` when `_` would do [explicit_into_iter_loop](https://github.com/Manishearth/rust-clippy/wiki#explicit_into_iter_loop) | warn | for-looping over `_.into_iter()` when `_` 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 [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 [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_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)` [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_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 instead of comparing difference with an epsilon [float_cmp](https://github.com/Manishearth/rust-clippy/wiki#float_cmp) | warn | using `==` or `!=` on float values instead of comparing difference with an epsilon
[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_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_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` [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` [identity_op](https://github.com/Manishearth/rust-clippy/wiki#identity_op) | warn | using identity operations, e.g. `x + 0` or `y / 1`
[if_let_some_result](https://github.com/Manishearth/rust-clippy/wiki#if_let_some_result) | warn | usage of `ok()` in `if let Some(pat)` statements is unnecessary, match on `Ok(pat)` instead [if_let_redundant_pattern_matching](https://github.com/Manishearth/rust-clippy/wiki#if_let_redundant_pattern_matching) | warn | use the proper utility function avoiding an `if let`
[if_not_else](https://github.com/Manishearth/rust-clippy/wiki#if_not_else) | allow | `if` branches that could be swapped so no negation operation is necessary on the condition [if_let_some_result](https://github.com/Manishearth/rust-clippy/wiki#if_let_some_result) | warn | usage of `ok()` in `if let Some(pat)` statements is unnecessary, match on `Ok(pat)` instead
[if_same_then_else](https://github.com/Manishearth/rust-clippy/wiki#if_same_then_else) | warn | if with the same *then* and *else* blocks [if_not_else](https://github.com/Manishearth/rust-clippy/wiki#if_not_else) | allow | `if` branches that could be swapped so no negation operation is necessary on the condition
[ifs_same_cond](https://github.com/Manishearth/rust-clippy/wiki#ifs_same_cond) | warn | consecutive `ifs` with the same 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
[indexing_slicing](https://github.com/Manishearth/rust-clippy/wiki#indexing_slicing) | allow | indexing/slicing usage [ifs_same_cond](https://github.com/Manishearth/rust-clippy/wiki#ifs_same_cond) | warn | consecutive `ifs` with the same condition
[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` [indexing_slicing](https://github.com/Manishearth/rust-clippy/wiki#indexing_slicing) | allow | indexing/slicing usage
[inline_always](https://github.com/Manishearth/rust-clippy/wiki#inline_always) | warn | use of `#[inline(always)]` [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`
[integer_arithmetic](https://github.com/Manishearth/rust-clippy/wiki#integer_arithmetic) | allow | any integer arithmetic statement [inline_always](https://github.com/Manishearth/rust-clippy/wiki#inline_always) | warn | use of `#[inline(always)]`
[invalid_regex](https://github.com/Manishearth/rust-clippy/wiki#invalid_regex) | deny | invalid regular expressions [integer_arithmetic](https://github.com/Manishearth/rust-clippy/wiki#integer_arithmetic) | allow | any integer arithmetic statement
[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 [invalid_regex](https://github.com/Manishearth/rust-clippy/wiki#invalid_regex) | deny | invalid regular expressions
[items_after_statements](https://github.com/Manishearth/rust-clippy/wiki#items_after_statements) | allow | blocks where an item comes after a statement [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
[iter_next_loop](https://github.com/Manishearth/rust-clippy/wiki#iter_next_loop) | warn | for-looping over `_.next()` which is probably not intended [items_after_statements](https://github.com/Manishearth/rust-clippy/wiki#items_after_statements) | allow | blocks where an item comes after a statement
[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 [iter_next_loop](https://github.com/Manishearth/rust-clippy/wiki#iter_next_loop) | warn | for-looping over `_.next()` which is probably not intended
[iter_skip_next](https://github.com/Manishearth/rust-clippy/wiki#iter_skip_next) | warn | using `.skip(x).next()` on an iterator [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 or impls with a public `len` method but no corresponding `is_empty` method [iter_skip_next](https://github.com/Manishearth/rust-clippy/wiki#iter_skip_next) | warn | using `.skip(x).next()` on an iterator
[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 [len_without_is_empty](https://github.com/Manishearth/rust-clippy/wiki#len_without_is_empty) | warn | traits or impls with a public `len` method but no corresponding `is_empty` method
[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 [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_unit_value](https://github.com/Manishearth/rust-clippy/wiki#let_unit_value) | warn | creating a let binding to a value of unit type, which usually can't be used afterwards [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
[linkedlist](https://github.com/Manishearth/rust-clippy/wiki#linkedlist) | warn | usage of LinkedList, usually a vector is faster, or a more specialized data structure like a VecDeque [let_unit_value](https://github.com/Manishearth/rust-clippy/wiki#let_unit_value) | warn | creating a let binding to a value of unit type, which usually can't be used afterwards
[logic_bug](https://github.com/Manishearth/rust-clippy/wiki#logic_bug) | warn | boolean expressions that contain terminals which can be eliminated [linkedlist](https://github.com/Manishearth/rust-clippy/wiki#linkedlist) | warn | usage of LinkedList, usually a vector is faster, or a more specialized data structure like a VecDeque
[manual_swap](https://github.com/Manishearth/rust-clippy/wiki#manual_swap) | warn | manual swap of two variables [logic_bug](https://github.com/Manishearth/rust-clippy/wiki#logic_bug) | warn | boolean expressions that contain terminals which can be eliminated
[many_single_char_names](https://github.com/Manishearth/rust-clippy/wiki#many_single_char_names) | warn | too many single character bindings [manual_swap](https://github.com/Manishearth/rust-clippy/wiki#manual_swap) | warn | manual swap of two variables
[map_clone](https://github.com/Manishearth/rust-clippy/wiki#map_clone) | warn | using `.map(|x| x.clone())` to clone an iterator or option's contents [many_single_char_names](https://github.com/Manishearth/rust-clippy/wiki#many_single_char_names) | warn | too many single character bindings
[map_entry](https://github.com/Manishearth/rust-clippy/wiki#map_entry) | warn | use of `contains_key` followed by `insert` on a `HashMap` or `BTreeMap` [map_clone](https://github.com/Manishearth/rust-clippy/wiki#map_clone) | warn | using `.map(|x| x.clone())` to clone an iterator or option's contents
[match_bool](https://github.com/Manishearth/rust-clippy/wiki#match_bool) | warn | a match on a boolean expression instead of an `if..else` block [map_entry](https://github.com/Manishearth/rust-clippy/wiki#map_entry) | warn | use of `contains_key` followed by `insert` on a `HashMap` or `BTreeMap`
[match_overlapping_arm](https://github.com/Manishearth/rust-clippy/wiki#match_overlapping_arm) | warn | a match with overlapping arms [match_bool](https://github.com/Manishearth/rust-clippy/wiki#match_bool) | warn | a match on a boolean expression instead of an `if..else` block
[match_ref_pats](https://github.com/Manishearth/rust-clippy/wiki#match_ref_pats) | warn | a match or `if let` with all arms prefixed with `&` instead of deref-ing the match expression [match_overlapping_arm](https://github.com/Manishearth/rust-clippy/wiki#match_overlapping_arm) | warn | a match with overlapping arms
[match_same_arms](https://github.com/Manishearth/rust-clippy/wiki#match_same_arms) | warn | `match` with identical arm bodies [match_ref_pats](https://github.com/Manishearth/rust-clippy/wiki#match_ref_pats) | warn | a match or `if let` with all arms prefixed with `&` instead of deref-ing the match expression
[mem_forget](https://github.com/Manishearth/rust-clippy/wiki#mem_forget) | allow | `mem::forget` usage on `Drop` types, likely to cause memory leaks [match_same_arms](https://github.com/Manishearth/rust-clippy/wiki#match_same_arms) | warn | `match` with identical arm bodies
[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 [mem_forget](https://github.com/Manishearth/rust-clippy/wiki#mem_forget) | allow | `mem::forget` usage on `Drop` types, likely to cause memory leaks
[misrefactored_assign_op](https://github.com/Manishearth/rust-clippy/wiki#misrefactored_assign_op) | warn | having a variable on both sides of an assign op [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
[missing_docs_in_private_items](https://github.com/Manishearth/rust-clippy/wiki#missing_docs_in_private_items) | allow | detects missing documentation for public and private members [misrefactored_assign_op](https://github.com/Manishearth/rust-clippy/wiki#misrefactored_assign_op) | warn | having a variable on both sides of an assign op
[mixed_case_hex_literals](https://github.com/Manishearth/rust-clippy/wiki#mixed_case_hex_literals) | warn | hex literals whose letter digits are not consistently upper- or lowercased [missing_docs_in_private_items](https://github.com/Manishearth/rust-clippy/wiki#missing_docs_in_private_items) | allow | detects missing documentation for public and private members
[module_inception](https://github.com/Manishearth/rust-clippy/wiki#module_inception) | warn | modules that have the same name as their parent module [mixed_case_hex_literals](https://github.com/Manishearth/rust-clippy/wiki#mixed_case_hex_literals) | warn | hex literals whose letter digits are not consistently upper- or lowercased
[modulo_one](https://github.com/Manishearth/rust-clippy/wiki#modulo_one) | warn | taking a number modulo 1, which always returns 0 [module_inception](https://github.com/Manishearth/rust-clippy/wiki#module_inception) | warn | modules that have the same name as their parent module
[mut_mut](https://github.com/Manishearth/rust-clippy/wiki#mut_mut) | allow | usage of double-mut refs, e.g. `&mut &mut ...` [modulo_one](https://github.com/Manishearth/rust-clippy/wiki#modulo_one) | warn | taking a number modulo 1, which always returns 0
[mutex_atomic](https://github.com/Manishearth/rust-clippy/wiki#mutex_atomic) | warn | using a mutex where an atomic value could be used instead [mut_mut](https://github.com/Manishearth/rust-clippy/wiki#mut_mut) | allow | usage of double-mut refs, e.g. `&mut &mut ...`
[mutex_integer](https://github.com/Manishearth/rust-clippy/wiki#mutex_integer) | allow | using a mutex for an integer type [mutex_atomic](https://github.com/Manishearth/rust-clippy/wiki#mutex_atomic) | warn | using a mutex where an atomic value could be used instead
[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 }` [mutex_integer](https://github.com/Manishearth/rust-clippy/wiki#mutex_integer) | allow | using a mutex for an integer type
[needless_borrow](https://github.com/Manishearth/rust-clippy/wiki#needless_borrow) | warn | taking a reference that is going to be automatically dereferenced [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_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_borrow](https://github.com/Manishearth/rust-clippy/wiki#needless_borrow) | warn | taking a reference that is going to be automatically dereferenced
[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_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_return](https://github.com/Manishearth/rust-clippy/wiki#needless_return) | warn | using a return statement like `return expr;` where an expression would suffice [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_update](https://github.com/Manishearth/rust-clippy/wiki#needless_update) | warn | using `Foo { ..base }` when there are no missing fields [needless_return](https://github.com/Manishearth/rust-clippy/wiki#needless_return) | warn | using a return statement like `return expr;` where an expression would suffice
[neg_multiply](https://github.com/Manishearth/rust-clippy/wiki#neg_multiply) | warn | multiplying integers with -1 [needless_update](https://github.com/Manishearth/rust-clippy/wiki#needless_update) | warn | using `Foo { ..base }` when there are no missing fields
[new_ret_no_self](https://github.com/Manishearth/rust-clippy/wiki#new_ret_no_self) | warn | not returning `Self` in a `new` method [neg_multiply](https://github.com/Manishearth/rust-clippy/wiki#neg_multiply) | warn | multiplying integers with -1
[new_without_default](https://github.com/Manishearth/rust-clippy/wiki#new_without_default) | warn | `fn new() -> Self` method without `Default` implementation [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_derive](https://github.com/Manishearth/rust-clippy/wiki#new_without_default_derive) | warn | `fn new() -> Self` without `#[derive]`able `Default` implementation [new_without_default](https://github.com/Manishearth/rust-clippy/wiki#new_without_default) | warn | `fn new() -> Self` method without `Default` implementation
[no_effect](https://github.com/Manishearth/rust-clippy/wiki#no_effect) | warn | statements with no effect [new_without_default_derive](https://github.com/Manishearth/rust-clippy/wiki#new_without_default_derive) | warn | `fn new() -> Self` without `#[derive]`able `Default` implementation
[non_ascii_literal](https://github.com/Manishearth/rust-clippy/wiki#non_ascii_literal) | allow | using any literal non-ASCII chars in a string literal instead of using the `\\u` escape [no_effect](https://github.com/Manishearth/rust-clippy/wiki#no_effect) | warn | statements with no effect
[nonminimal_bool](https://github.com/Manishearth/rust-clippy/wiki#nonminimal_bool) | allow | boolean expressions that can be written more concisely [non_ascii_literal](https://github.com/Manishearth/rust-clippy/wiki#non_ascii_literal) | allow | using any literal non-ASCII chars in a string literal instead of using the `\\u` escape
[nonsensical_open_options](https://github.com/Manishearth/rust-clippy/wiki#nonsensical_open_options) | warn | nonsensical combination of options for opening a file [nonminimal_bool](https://github.com/Manishearth/rust-clippy/wiki#nonminimal_bool) | allow | boolean expressions that can be written more concisely
[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` [nonsensical_open_options](https://github.com/Manishearth/rust-clippy/wiki#nonsensical_open_options) | warn | nonsensical combination of options for opening a file
[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 [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`
[option_map_unwrap_or](https://github.com/Manishearth/rust-clippy/wiki#option_map_unwrap_or) | allow | using `Option.map(f).unwrap_or(a)`, which is more succinctly expressed as `map_or(a, f)` [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_else](https://github.com/Manishearth/rust-clippy/wiki#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_map_unwrap_or](https://github.com/Manishearth/rust-clippy/wiki#option_map_unwrap_or) | allow | using `Option.map(f).unwrap_or(a)`, which is more succinctly expressed as `map_or(a, f)`
[option_unwrap_used](https://github.com/Manishearth/rust-clippy/wiki#option_unwrap_used) | allow | using `Option.unwrap()`, which should at least get a better message using `expect()` [option_map_unwrap_or_else](https://github.com/Manishearth/rust-clippy/wiki#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)`
[or_fun_call](https://github.com/Manishearth/rust-clippy/wiki#or_fun_call) | warn | using any `*or` method with a function call, which suggests `*or_else` [option_unwrap_used](https://github.com/Manishearth/rust-clippy/wiki#option_unwrap_used) | allow | using `Option.unwrap()`, which should at least get a better message using `expect()`
[out_of_bounds_indexing](https://github.com/Manishearth/rust-clippy/wiki#out_of_bounds_indexing) | deny | out of bounds constant indexing [or_fun_call](https://github.com/Manishearth/rust-clippy/wiki#or_fun_call) | warn | using any `*or` method with a function call, which suggests `*or_else`
[overflow_check_conditional](https://github.com/Manishearth/rust-clippy/wiki#overflow_check_conditional) | warn | overflow checks inspired by C which are likely to panic [out_of_bounds_indexing](https://github.com/Manishearth/rust-clippy/wiki#out_of_bounds_indexing) | deny | out of bounds constant indexing
[panic_params](https://github.com/Manishearth/rust-clippy/wiki#panic_params) | warn | missing parameters in `panic!` calls [overflow_check_conditional](https://github.com/Manishearth/rust-clippy/wiki#overflow_check_conditional) | warn | overflow checks inspired by C which are likely to panic
[precedence](https://github.com/Manishearth/rust-clippy/wiki#precedence) | warn | operations where precedence may be unclear [panic_params](https://github.com/Manishearth/rust-clippy/wiki#panic_params) | warn | missing parameters in `panic!` calls
[print_stdout](https://github.com/Manishearth/rust-clippy/wiki#print_stdout) | allow | printing on stdout [precedence](https://github.com/Manishearth/rust-clippy/wiki#precedence) | warn | operations where precedence may be unclear
[print_with_newline](https://github.com/Manishearth/rust-clippy/wiki#print_with_newline) | warn | using `print!()` with a format string that ends in a newline [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 [print_with_newline](https://github.com/Manishearth/rust-clippy/wiki#print_with_newline) | warn | using `print!()` with a format string that ends in a newline
[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 [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_zip_with_len](https://github.com/Manishearth/rust-clippy/wiki#range_zip_with_len) | warn | zipping iterator with a range when `enumerate()` would do [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
[redundant_closure](https://github.com/Manishearth/rust-clippy/wiki#redundant_closure) | warn | redundant closures, i.e. `|a| foo(a)` (which can be written as just `foo`) [range_zip_with_len](https://github.com/Manishearth/rust-clippy/wiki#range_zip_with_len) | warn | zipping iterator with a range when `enumerate()` would do
[redundant_closure_call](https://github.com/Manishearth/rust-clippy/wiki#redundant_closure_call) | warn | throwaway closures called in the expression they are defined [redundant_closure](https://github.com/Manishearth/rust-clippy/wiki#redundant_closure) | warn | redundant closures, i.e. `|a| foo(a)` (which can be written as just `foo`)
[redundant_pattern](https://github.com/Manishearth/rust-clippy/wiki#redundant_pattern) | warn | using `name @ _` in a pattern [redundant_closure_call](https://github.com/Manishearth/rust-clippy/wiki#redundant_closure_call) | warn | throwaway closures called in the expression they are defined
[regex_macro](https://github.com/Manishearth/rust-clippy/wiki#regex_macro) | warn | use of `regex!(_)` instead of `Regex::new(_)` [redundant_pattern](https://github.com/Manishearth/rust-clippy/wiki#redundant_pattern) | warn | using `name @ _` in a pattern
[result_unwrap_used](https://github.com/Manishearth/rust-clippy/wiki#result_unwrap_used) | allow | using `Result.unwrap()`, which might be better handled [regex_macro](https://github.com/Manishearth/rust-clippy/wiki#regex_macro) | warn | use of `regex!(_)` instead of `Regex::new(_)`
[reverse_range_loop](https://github.com/Manishearth/rust-clippy/wiki#reverse_range_loop) | warn | iteration over an empty range, such as `10..0` or `5..5` [result_unwrap_used](https://github.com/Manishearth/rust-clippy/wiki#result_unwrap_used) | allow | using `Result.unwrap()`, which might be better handled
[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()` [reverse_range_loop](https://github.com/Manishearth/rust-clippy/wiki#reverse_range_loop) | warn | iteration over an empty range, such as `10..0` or `5..5`
[serde_api_misuse](https://github.com/Manishearth/rust-clippy/wiki#serde_api_misuse) | warn | various things that will negatively affect your serde experience [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()`
[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` [serde_api_misuse](https://github.com/Manishearth/rust-clippy/wiki#serde_api_misuse) | warn | various things that will negatively affect your serde experience
[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_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_unrelated](https://github.com/Manishearth/rust-clippy/wiki#shadow_unrelated) | allow | rebinding a name without even using the original value [shadow_same](https://github.com/Manishearth/rust-clippy/wiki#shadow_same) | allow | rebinding a name to itself, e.g. `let mut x = &mut x`
[should_implement_trait](https://github.com/Manishearth/rust-clippy/wiki#should_implement_trait) | warn | defining a method that should be implementing a std trait [shadow_unrelated](https://github.com/Manishearth/rust-clippy/wiki#shadow_unrelated) | allow | rebinding a name without even using the original value
[similar_names](https://github.com/Manishearth/rust-clippy/wiki#similar_names) | allow | similarly named items and bindings [should_implement_trait](https://github.com/Manishearth/rust-clippy/wiki#should_implement_trait) | warn | defining a method that should be implementing a std trait
[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")` [similar_names](https://github.com/Manishearth/rust-clippy/wiki#similar_names) | allow | similarly named items and bindings
[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 `_ => {}`) instead of `if let` [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_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 instead of `if let` [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 `_ => {}`) instead of `if let`
[string_add](https://github.com/Manishearth/rust-clippy/wiki#string_add) | allow | using `x + ..` where x is a `String` instead of `push_str()` [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 instead of `if let`
[string_add_assign](https://github.com/Manishearth/rust-clippy/wiki#string_add_assign) | allow | using `x = x + ..` where x is a `String` instead of `push_str()` [string_add](https://github.com/Manishearth/rust-clippy/wiki#string_add) | allow | using `x + ..` where x is a `String` instead of `push_str()`
[string_lit_as_bytes](https://github.com/Manishearth/rust-clippy/wiki#string_lit_as_bytes) | warn | calling `as_bytes` on a string literal instead of using a byte string literal [string_add_assign](https://github.com/Manishearth/rust-clippy/wiki#string_add_assign) | allow | using `x = x + ..` where x is a `String` instead of `push_str()`
[stutter](https://github.com/Manishearth/rust-clippy/wiki#stutter) | allow | type names prefixed/postfixed with their containing module's name [string_lit_as_bytes](https://github.com/Manishearth/rust-clippy/wiki#string_lit_as_bytes) | warn | calling `as_bytes` on a string literal instead of using a byte string literal
[suspicious_assignment_formatting](https://github.com/Manishearth/rust-clippy/wiki#suspicious_assignment_formatting) | warn | suspicious formatting of `*=`, `-=` or `!=` [stutter](https://github.com/Manishearth/rust-clippy/wiki#stutter) | allow | type names prefixed/postfixed with their containing module's name
[suspicious_else_formatting](https://github.com/Manishearth/rust-clippy/wiki#suspicious_else_formatting) | warn | suspicious formatting of `else if` [suspicious_assignment_formatting](https://github.com/Manishearth/rust-clippy/wiki#suspicious_assignment_formatting) | warn | suspicious formatting of `*=`, `-=` or `!=`
[temporary_assignment](https://github.com/Manishearth/rust-clippy/wiki#temporary_assignment) | warn | assignments to temporaries [suspicious_else_formatting](https://github.com/Manishearth/rust-clippy/wiki#suspicious_else_formatting) | warn | suspicious formatting of `else if`
[temporary_cstring_as_ptr](https://github.com/Manishearth/rust-clippy/wiki#temporary_cstring_as_ptr) | warn | getting the inner pointer of a temporary `CString` [temporary_assignment](https://github.com/Manishearth/rust-clippy/wiki#temporary_assignment) | warn | assignments to temporaries
[too_many_arguments](https://github.com/Manishearth/rust-clippy/wiki#too_many_arguments) | warn | functions with too many arguments [temporary_cstring_as_ptr](https://github.com/Manishearth/rust-clippy/wiki#temporary_cstring_as_ptr) | warn | getting the inner pointer of a temporary `CString`
[toplevel_ref_arg](https://github.com/Manishearth/rust-clippy/wiki#toplevel_ref_arg) | warn | an entire binding declared as `ref`, in a function argument or a `let` statement [too_many_arguments](https://github.com/Manishearth/rust-clippy/wiki#too_many_arguments) | warn | functions with too many arguments
[transmute_ptr_to_ref](https://github.com/Manishearth/rust-clippy/wiki#transmute_ptr_to_ref) | warn | transmutes from a pointer to a reference type [toplevel_ref_arg](https://github.com/Manishearth/rust-clippy/wiki#toplevel_ref_arg) | warn | an entire binding declared as `ref`, in a function argument or a `let` statement
[trivial_regex](https://github.com/Manishearth/rust-clippy/wiki#trivial_regex) | warn | trivial regular expressions [transmute_ptr_to_ref](https://github.com/Manishearth/rust-clippy/wiki#transmute_ptr_to_ref) | warn | transmutes from a pointer to a reference type
[type_complexity](https://github.com/Manishearth/rust-clippy/wiki#type_complexity) | warn | usage of very complex types that might be better factored into `type` definitions [trivial_regex](https://github.com/Manishearth/rust-clippy/wiki#trivial_regex) | warn | trivial regular expressions
[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) [type_complexity](https://github.com/Manishearth/rust-clippy/wiki#type_complexity) | warn | usage of very complex types that might be better factored into `type` definitions
[unit_cmp](https://github.com/Manishearth/rust-clippy/wiki#unit_cmp) | warn | comparing unit values [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)
[unnecessary_mut_passed](https://github.com/Manishearth/rust-clippy/wiki#unnecessary_mut_passed) | warn | an argument passed as a mutable reference although the callee only demands an immutable reference [unit_cmp](https://github.com/Manishearth/rust-clippy/wiki#unit_cmp) | warn | comparing unit values
[unnecessary_operation](https://github.com/Manishearth/rust-clippy/wiki#unnecessary_operation) | warn | outer expressions with no effect [unnecessary_mut_passed](https://github.com/Manishearth/rust-clippy/wiki#unnecessary_mut_passed) | warn | an argument passed as a mutable reference although the callee only demands an immutable reference
[unneeded_field_pattern](https://github.com/Manishearth/rust-clippy/wiki#unneeded_field_pattern) | warn | struct fields bound to a wildcard instead of using `..` [unnecessary_operation](https://github.com/Manishearth/rust-clippy/wiki#unnecessary_operation) | warn | outer expressions with no effect
[unsafe_removed_from_name](https://github.com/Manishearth/rust-clippy/wiki#unsafe_removed_from_name) | warn | `unsafe` removed from API names on import [unneeded_field_pattern](https://github.com/Manishearth/rust-clippy/wiki#unneeded_field_pattern) | warn | struct fields bound to a wildcard instead of using `..`
[unseparated_literal_suffix](https://github.com/Manishearth/rust-clippy/wiki#unseparated_literal_suffix) | allow | literals whose suffix is not separated by an underscore [unsafe_removed_from_name](https://github.com/Manishearth/rust-clippy/wiki#unsafe_removed_from_name) | warn | `unsafe` removed from API names on import
[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 [unseparated_literal_suffix](https://github.com/Manishearth/rust-clippy/wiki#unseparated_literal_suffix) | allow | literals whose suffix is not separated by an underscore
[unused_label](https://github.com/Manishearth/rust-clippy/wiki#unused_label) | warn | unused labels [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_lifetimes](https://github.com/Manishearth/rust-clippy/wiki#unused_lifetimes) | warn | unused lifetimes in function definitions [unused_label](https://github.com/Manishearth/rust-clippy/wiki#unused_label) | warn | unused labels
[use_debug](https://github.com/Manishearth/rust-clippy/wiki#use_debug) | allow | use of `Debug`-based formatting [unused_lifetimes](https://github.com/Manishearth/rust-clippy/wiki#unused_lifetimes) | warn | unused lifetimes in function definitions
[used_underscore_binding](https://github.com/Manishearth/rust-clippy/wiki#used_underscore_binding) | allow | using a binding which is prefixed with an underscore [use_debug](https://github.com/Manishearth/rust-clippy/wiki#use_debug) | allow | use of `Debug`-based formatting
[useless_attribute](https://github.com/Manishearth/rust-clippy/wiki#useless_attribute) | warn | use of lint attributes on `extern crate` items [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_attribute](https://github.com/Manishearth/rust-clippy/wiki#useless_attribute) | warn | use of lint attributes on `extern crate` items
[useless_let_if_seq](https://github.com/Manishearth/rust-clippy/wiki#useless_let_if_seq) | warn | unidiomatic `let mut` declaration followed by initialization in `if` [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 or could be a cast/coercion [useless_let_if_seq](https://github.com/Manishearth/rust-clippy/wiki#useless_let_if_seq) | warn | unidiomatic `let mut` declaration followed by initialization in `if`
[useless_vec](https://github.com/Manishearth/rust-clippy/wiki#useless_vec) | warn | useless `vec!` [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
[while_let_loop](https://github.com/Manishearth/rust-clippy/wiki#while_let_loop) | warn | `loop { if let { ... } else break }`, which can be written as a `while let` loop [useless_vec](https://github.com/Manishearth/rust-clippy/wiki#useless_vec) | warn | useless `vec!`
[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 [while_let_loop](https://github.com/Manishearth/rust-clippy/wiki#while_let_loop) | warn | `loop { if let { ... } else break }`, which can be written as a `while let` loop
[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 [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_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_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_transmute](https://github.com/Manishearth/rust-clippy/wiki#wrong_transmute) | warn | transmutes that are confusing at best, undefined behaviour at worst and always useless [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
[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 [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_prefixed_literal](https://github.com/Manishearth/rust-clippy/wiki#zero_prefixed_literal) | warn | integer literals starting with `0` [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 [zero_prefixed_literal](https://github.com/Manishearth/rust-clippy/wiki#zero_prefixed_literal) | warn | integer literals starting with `0`
[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! More to come, please [file an issue](https://github.com/Manishearth/rust-clippy/issues) if you have ideas!

2
clippy_lints/src/approx_const.rs
View File

@ -76,7 +76,7 @@ fn check_lit(cx: &LateContext, lit: &Lit, e: &Expr) {
} }
fn check_known_consts(cx: &LateContext, e: &Expr, s: &str, module: &str) { fn check_known_consts(cx: &LateContext, e: &Expr, s: &str, module: &str) {
if let Ok(_) = s.parse::<f64>() { if s.parse::<f64>().is_ok() {
for &(constant, name, min_digits) in KNOWN_CONSTS { for &(constant, name, min_digits) in KNOWN_CONSTS {
if is_approx_const(constant, s, min_digits) { if is_approx_const(constant, s, min_digits) {
span_lint(cx, span_lint(cx,

2
clippy_lints/src/arithmetic.rs
View File

@ -49,7 +49,7 @@ impl LintPass for Arithmetic {
impl LateLintPass for Arithmetic { impl LateLintPass for Arithmetic {
fn check_expr(&mut self, cx: &LateContext, expr: &hir::Expr) { fn check_expr(&mut self, cx: &LateContext, expr: &hir::Expr) {
if let Some(_) = self.span { if self.span.is_some() {
return; return;
} }
match expr.node { match expr.node {

2
clippy_lints/src/doc.rs
View File

@ -322,7 +322,7 @@ fn check_doc(cx: &EarlyContext, valid_idents: &[String], docs: &[(&str, Span)])
if new_line { if new_line {
let mut lookup_parser = parser.clone(); let mut lookup_parser = parser.clone();
if let Some(_) = lookup_parser.find(|&(_, c)| c == ']') { if lookup_parser.any(|(_, c)| c == ']') {
if let Some((_, ':')) = lookup_parser.next() { if let Some((_, ':')) = lookup_parser.next() {
lookup_parser.next_line(); lookup_parser.next_line();
parser = lookup_parser; parser = lookup_parser;

91
clippy_lints/src/if_let_redundant_pattern_matching.rs Normal file
View File

@ -0,0 +1,91 @@
use rustc::lint::*;
use rustc::hir::*;
use syntax::codemap::Span;
use utils::{paths, span_lint_and_then, match_path, snippet};
/// **What it does:*** Lint for redundant pattern matching over `Result` or `Option`
///
/// **Why is this bad?** It's more concise and clear to just use the proper utility function
///
/// **Known problems:** None.
///
/// **Example:**
///
/// ```rust
/// if let Ok(_) = Ok::<i32, i32>(42) {}
/// if let Err(_) = Err::<i32, i32>(42) {}
/// if let None = None::<()> {}
/// if let Some(_) = Some(42) {}
/// ```
///
/// The more idiomatic use would be:
///
/// ```rust
/// if Ok::<i32, i32>(42).is_ok() {}
/// if Err::<i32, i32>(42).is_err() {}
/// if None::<()>.is_none() {}
/// if Some(42).is_some() {}
/// ```
///
declare_lint! {
pub IF_LET_REDUNDANT_PATTERN_MATCHING,
Warn,
"use the proper utility function avoiding an `if let`"
}
#[derive(Copy, Clone)]
pub struct Pass;
impl LintPass for Pass {
fn get_lints(&self) -> LintArray {
lint_array!(IF_LET_REDUNDANT_PATTERN_MATCHING)
}
}
impl LateLintPass for Pass {
fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
if let ExprMatch(ref op, ref arms, MatchSource::IfLetDesugar{..}) = expr.node {
if arms[0].pats.len() == 1 {
let good_method = match arms[0].pats[0].node {
PatKind::TupleStruct(ref path, ref pats, _) if pats.len() == 1 && pats[0].node == PatKind::Wild => {
if match_path(path, &paths::RESULT_OK) {
"is_ok()"
} else if match_path(path, &paths::RESULT_ERR) {
"is_err()"
} else if match_path(path, &paths::OPTION_SOME) {
"is_some()"
} else {
return
}
}
PatKind::Path(_, ref path) if match_path(path, &paths::OPTION_NONE) => {
"is_none()"
}
_ => return
};
span_lint_and_then(cx,
IF_LET_REDUNDANT_PATTERN_MATCHING,
arms[0].pats[0].span,
&format!("redundant pattern matching, consider using `{}`", good_method),
|db| {
let span = Span {
lo: expr.span.lo,
hi: op.span.hi,
expn_id: expr.span.expn_id,
};
db.span_suggestion(span,
"try this",
format!("if {}.{}", snippet(cx, op.span, "_"), good_method));
});
}
}
}
}

3
clippy_lints/src/lib.rs
View File

@ -82,6 +82,7 @@ pub mod format;
pub mod formatting; pub mod formatting;
pub mod functions; pub mod functions;
pub mod identity_op; pub mod identity_op;
pub mod if_let_redundant_pattern_matching;
pub mod if_not_else; pub mod if_not_else;
pub mod items_after_statements; pub mod items_after_statements;
pub mod len_zero; pub mod len_zero;
@ -257,6 +258,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) {
reg.register_late_lint_pass(box eval_order_dependence::EvalOrderDependence); reg.register_late_lint_pass(box eval_order_dependence::EvalOrderDependence);
reg.register_late_lint_pass(box missing_doc::MissingDoc::new()); reg.register_late_lint_pass(box missing_doc::MissingDoc::new());
reg.register_late_lint_pass(box ok_if_let::Pass); reg.register_late_lint_pass(box ok_if_let::Pass);
reg.register_late_lint_pass(box if_let_redundant_pattern_matching::Pass);
reg.register_lint_group("clippy_restrictions", vec![ reg.register_lint_group("clippy_restrictions", vec![
arithmetic::FLOAT_ARITHMETIC, arithmetic::FLOAT_ARITHMETIC,
@ -344,6 +346,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) {
functions::NOT_UNSAFE_PTR_ARG_DEREF, functions::NOT_UNSAFE_PTR_ARG_DEREF,
functions::TOO_MANY_ARGUMENTS, functions::TOO_MANY_ARGUMENTS,
identity_op::IDENTITY_OP, identity_op::IDENTITY_OP,
if_let_redundant_pattern_matching::IF_LET_REDUNDANT_PATTERN_MATCHING,
len_zero::LEN_WITHOUT_IS_EMPTY, len_zero::LEN_WITHOUT_IS_EMPTY,
len_zero::LEN_ZERO, len_zero::LEN_ZERO,
let_if_seq::USELESS_LET_IF_SEQ, let_if_seq::USELESS_LET_IF_SEQ,

4
clippy_lints/src/methods.rs
View File

@ -532,7 +532,7 @@ impl LateLintPass for Pass {
lint_iter_nth(cx, expr, arglists[0], false); lint_iter_nth(cx, expr, arglists[0], false);
} else if let Some(arglists) = method_chain_args(expr, &["iter_mut", "nth"]) { } else if let Some(arglists) = method_chain_args(expr, &["iter_mut", "nth"]) {
lint_iter_nth(cx, expr, arglists[0], true); lint_iter_nth(cx, expr, arglists[0], true);
} else if let Some(_) = method_chain_args(expr, &["skip", "next"]) { } else if method_chain_args(expr, &["skip", "next"]).is_some() {
lint_iter_skip_next(cx, expr); lint_iter_skip_next(cx, expr);
} }
@ -796,7 +796,7 @@ fn lint_cstring_as_ptr(cx: &LateContext, expr: &hir::Expr, new: &hir::Expr, unwr
// Type of MethodArgs is potentially a Vec // Type of MethodArgs is potentially a Vec
fn lint_iter_nth(cx: &LateContext, expr: &hir::Expr, iter_args: &MethodArgs, is_mut: bool){ fn lint_iter_nth(cx: &LateContext, expr: &hir::Expr, iter_args: &MethodArgs, is_mut: bool){
let mut_str = if is_mut { "_mut" } else {""}; let mut_str = if is_mut { "_mut" } else {""};
let caller_type = if let Some(_) = derefs_to_slice(cx, &iter_args[0], cx.tcx.expr_ty(&iter_args[0])) { let caller_type = if derefs_to_slice(cx, &iter_args[0], cx.tcx.expr_ty(&iter_args[0])).is_some() {
"slice" "slice"
} }
else if match_type(cx, cx.tcx.expr_ty(&iter_args[0]), &paths::VEC) { else if match_type(cx, cx.tcx.expr_ty(&iter_args[0]), &paths::VEC) {

2
clippy_lints/src/minmax.rs
View File

@ -85,7 +85,7 @@ fn fetch_const(args: &[P<Expr>], m: MinMax) -> Option<(MinMax, Constant, &Expr)>
return None; return None;
} }
if let Some(c) = constant_simple(&args[0]) { if let Some(c) = constant_simple(&args[0]) {
if let None = constant_simple(&args[1]) { if constant_simple(&args[1]).is_none() {
// otherwise ignore // otherwise ignore
Some((m, c, &args[1])) Some((m, c, &args[1]))
} else { } else {

4
clippy_lints/src/ok_if_let.rs
View File

@ -38,7 +38,7 @@ impl LateLintPass for Pass {
let MatchSource::IfLetDesugar { .. } = *source, //test if it is an If Let let MatchSource::IfLetDesugar { .. } = *source, //test if it is an If Let
let ExprMethodCall(_, _, ref result_types) = op.node, //check is expr.ok() has type Result<T,E>.ok() let ExprMethodCall(_, _, ref result_types) = op.node, //check is expr.ok() has type Result<T,E>.ok()
let PatKind::TupleStruct(ref x, ref y, _) = body[0].pats[0].node, //get operation let PatKind::TupleStruct(ref x, ref y, _) = body[0].pats[0].node, //get operation
let Some(_) = method_chain_args(op, &["ok"]) //test to see if using ok() methoduse std::marker::Sized; method_chain_args(op, &["ok"]).is_some() //test to see if using ok() methoduse std::marker::Sized;
], { ], {
let is_result_type = match_type(cx, cx.tcx.expr_ty(&result_types[0]), &paths::RESULT); let is_result_type = match_type(cx, cx.tcx.expr_ty(&result_types[0]), &paths::RESULT);
@ -46,7 +46,7 @@ impl LateLintPass for Pass {
if print::path_to_string(x) == "Some" && is_result_type { if print::path_to_string(x) == "Some" && is_result_type {
span_help_and_lint(cx, IF_LET_SOME_RESULT, expr.span, span_help_and_lint(cx, IF_LET_SOME_RESULT, expr.span,
"Matching on `Some` with `ok()` is redundant", "Matching on `Some` with `ok()` is redundant",
&format!("Consider matching on `Ok({})` and removing the call to `ok` instead", some_expr_string)); &format!("Consider matching on `Ok({})` and removing the call to `ok` instead", some_expr_string));
} }
}} }}
} }

4
clippy_lints/src/utils/paths.rs
View File

@ -34,6 +34,8 @@ pub const MUTEX: [&'static str; 4] = ["std", "sync", "mutex", "Mutex"];
pub const OPEN_OPTIONS: [&'static str; 3] = ["std", "fs", "OpenOptions"]; pub const OPEN_OPTIONS: [&'static str; 3] = ["std", "fs", "OpenOptions"];
pub const OPS_MODULE: [&'static str; 2] = ["core", "ops"]; pub const OPS_MODULE: [&'static str; 2] = ["core", "ops"];
pub const OPTION: [&'static str; 3] = ["core", "option", "Option"]; pub const OPTION: [&'static str; 3] = ["core", "option", "Option"];
pub const OPTION_NONE: [&'static str; 4] = ["core", "option", "Option", "None"];
pub const OPTION_SOME: [&'static str; 4] = ["core", "option", "Option", "Some"];
pub const PTR_NULL: [&'static str; 2] = ["ptr", "null"]; pub const PTR_NULL: [&'static str; 2] = ["ptr", "null"];
pub const PTR_NULL_MUT: [&'static str; 2] = ["ptr", "null_mut"]; pub const PTR_NULL_MUT: [&'static str; 2] = ["ptr", "null_mut"];
pub const RANGE: [&'static str; 3] = ["core", "ops", "Range"]; pub const RANGE: [&'static str; 3] = ["core", "ops", "Range"];
@ -59,6 +61,8 @@ pub const REGEX_BYTES_SET_NEW: [&'static str; 5] = ["regex", "re_set", "bytes",
pub const REGEX_NEW: [&'static str; 4] = ["regex", "re_unicode", "Regex", "new"]; pub const REGEX_NEW: [&'static str; 4] = ["regex", "re_unicode", "Regex", "new"];
pub const REGEX_SET_NEW: [&'static str; 5] = ["regex", "re_set", "unicode", "RegexSet", "new"]; pub const REGEX_SET_NEW: [&'static str; 5] = ["regex", "re_set", "unicode", "RegexSet", "new"];
pub const RESULT: [&'static str; 3] = ["core", "result", "Result"]; pub const RESULT: [&'static str; 3] = ["core", "result", "Result"];
pub const RESULT_ERR: [&'static str; 4] = ["core", "result", "Result", "Err"];
pub const RESULT_OK: [&'static str; 4] = ["core", "result", "Result", "Ok"];
pub const SERDE_DE_VISITOR: [&'static str; 3] = ["serde", "de", "Visitor"]; pub const SERDE_DE_VISITOR: [&'static str; 3] = ["serde", "de", "Visitor"];
pub const STRING: [&'static str; 3] = ["collections", "string", "String"]; pub const STRING: [&'static str; 3] = ["collections", "string", "String"];
pub const TRANSMUTE: [&'static str; 4] = ["core", "intrinsics", "", "transmute"]; pub const TRANSMUTE: [&'static str; 4] = ["core", "intrinsics", "", "transmute"];

53
tests/compile-fail/if_let_redundant_pattern_matching.rs Normal file
View File

@ -0,0 +1,53 @@
#![feature(plugin)]
#![plugin(clippy)]
#![deny(clippy)]
#![deny(if_let_redundant_pattern_matching)]
fn main() {
if let Ok(_) = Ok::<i32, i32>(42) {}
//~^ERROR redundant pattern matching, consider using `is_ok()`
//~| HELP try this
//~| SUGGESTION if Ok::<i32, i32>(42).is_ok() {
if let Err(_) = Err::<i32, i32>(42) {
//~^ERROR redundant pattern matching, consider using `is_err()`
//~| HELP try this
//~| SUGGESTION if Err::<i32, i32>(42).is_err() {
}
if let None = None::<()> {
//~^ERROR redundant pattern matching, consider using `is_none()`
//~| HELP try this
//~| SUGGESTION if None::<()>.is_none() {
}
if let Some(_) = Some(42) {
//~^ERROR redundant pattern matching, consider using `is_some()`
//~| HELP try this
//~| SUGGESTION if Some(42).is_some() {
}
if Ok::<i32, i32>(42).is_ok() {
}
if Err::<i32, i32>(42).is_err() {
}
if None::<i32>.is_none() {
}
if Some(42).is_some() {
}
if let Ok(x) = Ok::<i32,i32>(42) {
println!("{}", x);
}
}

2
tests/compile-fail/matches.rs
View File

@ -2,7 +2,7 @@
#![plugin(clippy)] #![plugin(clippy)]
#![deny(clippy)] #![deny(clippy)]
#![allow(unused)] #![allow(unused, if_let_redundant_pattern_matching)]
#![deny(single_match_else)] #![deny(single_match_else)]
use std::borrow::Cow; use std::borrow::Cow;