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Auto merge of #7608 - andrewpollack:7594/while_let_some_result, r=Manishearth

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#7594: Adding new 'while_let_some_result' linting

Excited for the opportunity to contribute to Clippy! Since the latest Bay Area Rust Meetup, I've been looking for an opportunity and found it 😄

Please let me know how I can improve this PR! Much of it is similar to ``[`if_let_some_result`]``, but I followed the description in the issue to create its own linting rules. Looking forward to feedback, and continuing to work on Clippy in the future!

changelog: Renamed Lint: `if_let_some_result` is now called [`match_result_ok`]. Now also handles `while let` case.
This commit is contained in:
bors 2021-09-28 05:33:57 +00:00
commit cbf27d0762
8 changed files with 187 additions and 88 deletions
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8
CHANGELOG.md
View File

@ -8,6 +8,10 @@ document.
[74d1561...master](https://github.com/rust-lang/rust-clippy/compare/74d1561...master)
### New Lints
* Renamed Lint: `if_let_some_result` is now called [`match_result_ok`]. Now also handles `while let` case.
## Rust 1.55
Current beta, release 2021-09-09
@ -1491,7 +1495,7 @@ Released 2020-03-12
* `unknown_clippy_lints` [#4963](https://github.com/rust-lang/rust-clippy/pull/4963)
* [`explicit_into_iter_loop`] [#4978](https://github.com/rust-lang/rust-clippy/pull/4978)
* [`useless_attribute`] [#5022](https://github.com/rust-lang/rust-clippy/pull/5022)
* [`if_let_some_result`] [#5032](https://github.com/rust-lang/rust-clippy/pull/5032)
* `if_let_some_result` [#5032](https://github.com/rust-lang/rust-clippy/pull/5032)
### ICE fixes
@ -2685,7 +2689,6 @@ Released 2018-09-13
[`identity_op`]: https://rust-lang.github.io/rust-clippy/master/index.html#identity_op
[`if_let_mutex`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_let_mutex
[`if_let_redundant_pattern_matching`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_let_redundant_pattern_matching
[`if_let_some_result`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_let_some_result
[`if_not_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_not_else
[`if_same_then_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_same_then_else
[`if_then_panic`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_then_panic
@ -2775,6 +2778,7 @@ Released 2018-09-13
[`match_on_vec_items`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_on_vec_items
[`match_overlapping_arm`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_overlapping_arm
[`match_ref_pats`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_ref_pats
[`match_result_ok`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_result_ok
[`match_same_arms`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_same_arms
[`match_single_binding`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_single_binding
[`match_wild_err_arm`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_wild_err_arm

11
clippy_lints/src/lib.rs
View File

@ -225,7 +225,6 @@ mod future_not_send;
mod get_last_with_len;
mod identity_op;
mod if_let_mutex;
mod if_let_some_result;
mod if_not_else;
mod if_then_panic;
mod if_then_some_else_none;
@ -264,6 +263,7 @@ mod map_clone;
mod map_err_ignore;
mod map_unit_fn;
mod match_on_vec_items;
mod match_result_ok;
mod matches;
mod mem_discriminant;
mod mem_forget;
@ -658,7 +658,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
get_last_with_len::GET_LAST_WITH_LEN,
identity_op::IDENTITY_OP,
if_let_mutex::IF_LET_MUTEX,
if_let_some_result::IF_LET_SOME_RESULT,
if_not_else::IF_NOT_ELSE,
if_then_panic::IF_THEN_PANIC,
if_then_some_else_none::IF_THEN_SOME_ELSE_NONE,
@ -728,6 +727,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
map_unit_fn::OPTION_MAP_UNIT_FN,
map_unit_fn::RESULT_MAP_UNIT_FN,
match_on_vec_items::MATCH_ON_VEC_ITEMS,
match_result_ok::MATCH_RESULT_OK,
matches::INFALLIBLE_DESTRUCTURING_MATCH,
matches::MATCH_AS_REF,
matches::MATCH_BOOL,
@ -1259,7 +1259,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(get_last_with_len::GET_LAST_WITH_LEN),
LintId::of(identity_op::IDENTITY_OP),
LintId::of(if_let_mutex::IF_LET_MUTEX),
LintId::of(if_let_some_result::IF_LET_SOME_RESULT),
LintId::of(if_then_panic::IF_THEN_PANIC),
LintId::of(indexing_slicing::OUT_OF_BOUNDS_INDEXING),
LintId::of(infinite_iter::INFINITE_ITER),
@ -1303,6 +1302,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(map_clone::MAP_CLONE),
LintId::of(map_unit_fn::OPTION_MAP_UNIT_FN),
LintId::of(map_unit_fn::RESULT_MAP_UNIT_FN),
LintId::of(match_result_ok::MATCH_RESULT_OK),
LintId::of(matches::INFALLIBLE_DESTRUCTURING_MATCH),
LintId::of(matches::MATCH_AS_REF),
LintId::of(matches::MATCH_LIKE_MATCHES_MACRO),
@ -1513,7 +1513,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(functions::DOUBLE_MUST_USE),
LintId::of(functions::MUST_USE_UNIT),
LintId::of(functions::RESULT_UNIT_ERR),
LintId::of(if_let_some_result::IF_LET_SOME_RESULT),
LintId::of(if_then_panic::IF_THEN_PANIC),
LintId::of(inherent_to_string::INHERENT_TO_STRING),
LintId::of(len_zero::COMPARISON_TO_EMPTY),
@ -1530,6 +1529,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(manual_map::MANUAL_MAP),
LintId::of(manual_non_exhaustive::MANUAL_NON_EXHAUSTIVE),
LintId::of(map_clone::MAP_CLONE),
LintId::of(match_result_ok::MATCH_RESULT_OK),
LintId::of(matches::INFALLIBLE_DESTRUCTURING_MATCH),
LintId::of(matches::MATCH_LIKE_MATCHES_MACRO),
LintId::of(matches::MATCH_OVERLAPPING_ARM),
@ -1985,7 +1985,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
store.register_late_pass(|| Box::new(missing_doc::MissingDoc::new()));
store.register_late_pass(|| Box::new(missing_inline::MissingInline));
store.register_late_pass(move || Box::new(exhaustive_items::ExhaustiveItems));
store.register_late_pass(|| Box::new(if_let_some_result::OkIfLet));
store.register_late_pass(|| Box::new(match_result_ok::MatchResultOk));
store.register_late_pass(|| Box::new(partialeq_ne_impl::PartialEqNeImpl));
store.register_late_pass(|| Box::new(unused_io_amount::UnusedIoAmount));
let enum_variant_size_threshold = conf.enum_variant_size_threshold;
@ -2212,6 +2212,7 @@ pub fn register_renamed(ls: &mut rustc_lint::LintStore) {
ls.register_renamed("clippy::identity_conversion", "clippy::useless_conversion");
ls.register_renamed("clippy::zero_width_space", "clippy::invisible_characters");
ls.register_renamed("clippy::single_char_push_str", "clippy::single_char_add_str");
ls.register_renamed("clippy::if_let_some_result", "clippy::match_result_ok");
// uplifted lints
ls.register_renamed("clippy::invalid_ref", "invalid_value");

55
clippy_lints/src/if_let_some_result.rs → clippy_lints/src/match_result_ok.rs
View File

@ -12,40 +12,51 @@ use rustc_span::sym;
declare_clippy_lint! {
/// ### What it does
///* Checks for unnecessary `ok()` in if let.
/// Checks for unnecessary `ok()` in `while let`.
///
/// ### Why is this bad?
/// Calling `ok()` in if let is unnecessary, instead match
/// Calling `ok()` in `while let` is unnecessary, instead match
/// on `Ok(pat)`
///
/// ### Example
/// ```ignore
/// for i in iter {
/// if let Some(value) = i.parse().ok() {
/// vec.push(value)
/// }
/// while let Some(value) = iter.next().ok() {
/// vec.push(value)
/// }
/// ```
/// Could be written:
///
/// ```ignore
/// for i in iter {
/// if let Ok(value) = i.parse() {
/// vec.push(value)
/// }
/// if let Some(valie) = iter.next().ok() {
/// vec.push(value)
/// }
/// ```
pub IF_LET_SOME_RESULT,
/// Use instead:
/// ```ignore
/// while let Ok(value) = iter.next() {
/// vec.push(value)
/// }
///
/// if let Ok(value) = iter.next() {
/// vec.push_value)
/// }
/// ```
pub MATCH_RESULT_OK,
style,
"usage of `ok()` in `if let Some(pat)` statements is unnecessary, match on `Ok(pat)` instead"
"usage of `ok()` in `let Some(pat)` statements is unnecessary, match on `Ok(pat)` instead"
}
declare_lint_pass!(OkIfLet => [IF_LET_SOME_RESULT]);
declare_lint_pass!(MatchResultOk => [MATCH_RESULT_OK]);
impl<'tcx> LateLintPass<'tcx> for OkIfLet {
impl<'tcx> LateLintPass<'tcx> for MatchResultOk {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if_chain! { //begin checking variables
if let Some(higher::IfLet { let_pat, let_expr, .. }) = higher::IfLet::hir(cx, expr);
let (let_pat, let_expr, ifwhile) =
if let Some(higher::IfLet { let_pat, let_expr, .. }) = higher::IfLet::hir(cx, expr) {
(let_pat, let_expr, "if")
} else if let Some(higher::WhileLet { let_pat, let_expr, .. }) = higher::WhileLet::hir(expr) {
(let_pat, let_expr, "while")
} else {
return;
};
if_chain! {
if let ExprKind::MethodCall(_, ok_span, [ref result_types_0, ..], _) = let_expr.kind; //check is expr.ok() has type Result<T,E>.ok(, _)
if let PatKind::TupleStruct(QPath::Resolved(_, x), y, _) = let_pat.kind; //get operation
if method_chain_args(let_expr, &["ok"]).is_some(); //test to see if using ok() methoduse std::marker::Sized;
@ -53,17 +64,19 @@ impl<'tcx> LateLintPass<'tcx> for OkIfLet {
if rustc_hir_pretty::to_string(rustc_hir_pretty::NO_ANN, |s| s.print_path(x, false)) == "Some";
then {
let mut applicability = Applicability::MachineApplicable;
let some_expr_string = snippet_with_applicability(cx, y[0].span, "", &mut applicability);
let trimmed_ok = snippet_with_applicability(cx, let_expr.span.until(ok_span), "", &mut applicability);
let sugg = format!(
"if let Ok({}) = {}",
"{} let Ok({}) = {}",
ifwhile,
some_expr_string,
trimmed_ok.trim().trim_end_matches('.'),
);
span_lint_and_sugg(
cx,
IF_LET_SOME_RESULT,
MATCH_RESULT_OK,
expr.span.with_hi(let_expr.span.hi()),
"matching on `Some` with `ok()` is redundant",
&format!("consider matching on `Ok({})` and removing the call to `ok` instead", some_expr_string),

28
tests/ui/if_let_some_result.fixed
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@ -1,28 +0,0 @@
// run-rustfix
#![warn(clippy::if_let_some_result)]
#![allow(dead_code)]
fn str_to_int(x: &str) -> i32 {
if let Ok(y) = x.parse() { y } else { 0 }
}
fn str_to_int_ok(x: &str) -> i32 {
if let Ok(y) = x.parse() { y } else { 0 }
}
#[rustfmt::skip]
fn strange_some_no_else(x: &str) -> i32 {
{
if let Ok(y) = x . parse() {
return y;
};
0
}
}
fn negative() {
while let Some(1) = "".parse().ok() {}
}
fn main() {}

28
tests/ui/if_let_some_result.rs
View File

@ -1,28 +0,0 @@
// run-rustfix
#![warn(clippy::if_let_some_result)]
#![allow(dead_code)]
fn str_to_int(x: &str) -> i32 {
if let Some(y) = x.parse().ok() { y } else { 0 }
}
fn str_to_int_ok(x: &str) -> i32 {
if let Ok(y) = x.parse() { y } else { 0 }
}
#[rustfmt::skip]
fn strange_some_no_else(x: &str) -> i32 {
{
if let Some(y) = x . parse() . ok () {
return y;
};
0
}
}
fn negative() {
while let Some(1) = "".parse().ok() {}
}
fn main() {}

63
tests/ui/match_result_ok.fixed Normal file
View File

@ -0,0 +1,63 @@
// run-rustfix
#![warn(clippy::match_result_ok)]
#![allow(clippy::boxed_local)]
#![allow(dead_code)]
// Checking `if` cases
fn str_to_int(x: &str) -> i32 {
if let Ok(y) = x.parse() { y } else { 0 }
}
fn str_to_int_ok(x: &str) -> i32 {
if let Ok(y) = x.parse() { y } else { 0 }
}
#[rustfmt::skip]
fn strange_some_no_else(x: &str) -> i32 {
{
if let Ok(y) = x . parse() {
return y;
};
0
}
}
// Checking `while` cases
struct Wat {
counter: i32,
}
impl Wat {
fn next(&mut self) -> Result<i32, &str> {
self.counter += 1;
if self.counter < 5 {
Ok(self.counter)
} else {
Err("Oh no")
}
}
}
fn base_1(x: i32) {
let mut wat = Wat { counter: x };
while let Ok(a) = wat.next() {
println!("{}", a);
}
}
fn base_2(x: i32) {
let mut wat = Wat { counter: x };
while let Ok(a) = wat.next() {
println!("{}", a);
}
}
fn base_3(test_func: Box<Result<i32, &str>>) {
// Expected to stay as is
while let Some(_b) = test_func.ok() {}
}
fn main() {}

63
tests/ui/match_result_ok.rs Normal file
View File

@ -0,0 +1,63 @@
// run-rustfix
#![warn(clippy::match_result_ok)]
#![allow(clippy::boxed_local)]
#![allow(dead_code)]
// Checking `if` cases
fn str_to_int(x: &str) -> i32 {
if let Some(y) = x.parse().ok() { y } else { 0 }
}
fn str_to_int_ok(x: &str) -> i32 {
if let Ok(y) = x.parse() { y } else { 0 }
}
#[rustfmt::skip]
fn strange_some_no_else(x: &str) -> i32 {
{
if let Some(y) = x . parse() . ok () {
return y;
};
0
}
}
// Checking `while` cases
struct Wat {
counter: i32,
}
impl Wat {
fn next(&mut self) -> Result<i32, &str> {
self.counter += 1;
if self.counter < 5 {
Ok(self.counter)
} else {
Err("Oh no")
}
}
}
fn base_1(x: i32) {
let mut wat = Wat { counter: x };
while let Some(a) = wat.next().ok() {
println!("{}", a);
}
}
fn base_2(x: i32) {
let mut wat = Wat { counter: x };
while let Ok(a) = wat.next() {
println!("{}", a);
}
}
fn base_3(test_func: Box<Result<i32, &str>>) {
// Expected to stay as is
while let Some(_b) = test_func.ok() {}
}
fn main() {}

19
tests/ui/if_let_some_result.stderr → tests/ui/match_result_ok.stderr
View File

@ -1,17 +1,17 @@
error: matching on `Some` with `ok()` is redundant
--> $DIR/if_let_some_result.rs:7:5
--> $DIR/match_result_ok.rs:10:5
|
LL | if let Some(y) = x.parse().ok() { y } else { 0 }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `-D clippy::if-let-some-result` implied by `-D warnings`
= note: `-D clippy::match-result-ok` implied by `-D warnings`
help: consider matching on `Ok(y)` and removing the call to `ok` instead
|
LL | if let Ok(y) = x.parse() { y } else { 0 }
| ~~~~~~~~~~~~~~~~~~~~~~~~
error: matching on `Some` with `ok()` is redundant
--> $DIR/if_let_some_result.rs:17:9
--> $DIR/match_result_ok.rs:20:9
|
LL | if let Some(y) = x . parse() . ok () {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -21,5 +21,16 @@ help: consider matching on `Ok(y)` and removing the call to `ok` instead
LL | if let Ok(y) = x . parse() {
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to 2 previous errors
error: matching on `Some` with `ok()` is redundant
--> $DIR/match_result_ok.rs:46:5
|
LL | while let Some(a) = wat.next().ok() {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: consider matching on `Ok(a)` and removing the call to `ok` instead
|
LL | while let Ok(a) = wat.next() {
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to 3 previous errors