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Auto merge of #6119 - rsulli55:find_is_some_on_strs, r=flip1995

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Add a case to `lint_search_is_some` to handle searching strings

Fixes: #6010

This adds a lint which recommends using `contains()` instead of `find()` followed by `is_some()` on strings as suggested in #6010.

This was added as an additional case to
5af88e3c2d/clippy_lints/src/methods/mod.rs (L3037)

I would really appreciate any comments/suggestions for my code!

changelog: Added case to `lint_search_is_some` to handle searching strings
This commit is contained in:
bors 2020-11-16 08:45:10 +00:00
commit ad4f82997a
9 changed files with 280 additions and 121 deletions
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44
clippy_lints/src/methods/mod.rs
View File

@ -515,11 +515,11 @@ declare_clippy_lint! {
}
declare_clippy_lint! {
/// **What it does:** Checks for an iterator search (such as `find()`,
/// **What it does:** Checks for an iterator or string search (such as `find()`,
/// `position()`, or `rposition()`) followed by a call to `is_some()`.
///
/// **Why is this bad?** Readability, this can be written more concisely as
/// `_.any(_)`.
/// `_.any(_)` or `_.contains(_)`.
///
/// **Known problems:** None.
///
@ -535,7 +535,7 @@ declare_clippy_lint! {
/// ```
pub SEARCH_IS_SOME,
complexity,
"using an iterator search followed by `is_some()`, which is more succinctly expressed as a call to `any()`"
"using an iterator or string search followed by `is_some()`, which is more succinctly expressed as a call to `any()` or `contains()`"
}
declare_clippy_lint! {
@ -3041,6 +3041,7 @@ fn lint_flat_map_identity<'tcx>(
}
/// lint searching an Iterator followed by `is_some()`
/// or calling `find()` on a string followed by `is_some()`
fn lint_search_is_some<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
@ -3052,10 +3053,10 @@ fn lint_search_is_some<'tcx>(
// lint if caller of search is an Iterator
if match_trait_method(cx, &is_some_args[0], &paths::ITERATOR) {
let msg = format!(
"called `is_some()` after searching an `Iterator` with {}. This is more succinctly \
expressed by calling `any()`.",
"called `is_some()` after searching an `Iterator` with `{}`",
search_method
);
let hint = "this is more succinctly expressed by calling `any()`";
let search_snippet = snippet(cx, search_args[1].span, "..");
if search_snippet.lines().count() <= 1 {
// suggest `any(|x| ..)` instead of `any(|&x| ..)` for `find(|&x| ..).is_some()`
@ -3083,7 +3084,7 @@ fn lint_search_is_some<'tcx>(
SEARCH_IS_SOME,
method_span.with_hi(expr.span.hi()),
&msg,
"try this",
"use `any()` instead",
format!(
"any({})",
any_search_snippet.as_ref().map_or(&*search_snippet, String::as_str)
@ -3091,7 +3092,36 @@ fn lint_search_is_some<'tcx>(
Applicability::MachineApplicable,
);
} else {
span_lint(cx, SEARCH_IS_SOME, expr.span, &msg);
span_lint_and_help(cx, SEARCH_IS_SOME, expr.span, &msg, None, hint);
}
}
// lint if `find()` is called by `String` or `&str`
else if search_method == "find" {
let is_string_or_str_slice = |e| {
let self_ty = cx.typeck_results().expr_ty(e).peel_refs();
if is_type_diagnostic_item(cx, self_ty, sym!(string_type)) {
true
} else {
*self_ty.kind() == ty::Str
}
};
if_chain! {
if is_string_or_str_slice(&search_args[0]);
if is_string_or_str_slice(&search_args[1]);
then {
let msg = "called `is_some()` after calling `find()` on a string";
let mut applicability = Applicability::MachineApplicable;
let find_arg = snippet_with_applicability(cx, search_args[1].span, "..", &mut applicability);
span_lint_and_sugg(
cx,
SEARCH_IS_SOME,
method_span.with_hi(expr.span.hi()),
msg,
"use `contains()` instead",
format!("contains({})", find_arg),
applicability,
);
}
}
}
}

2
src/lintlist/mod.rs
View File

@ -2121,7 +2121,7 @@ vec![
Lint {
name: "search_is_some",
group: "complexity",
desc: "using an iterator search followed by `is_some()`, which is more succinctly expressed as a call to `any()`",
desc: "using an iterator or string search followed by `is_some()`, which is more succinctly expressed as a call to `any()` or `contains()`",
deprecation: None,
module: "methods",
},

44
tests/ui/methods.rs
View File

@ -133,50 +133,6 @@ fn filter_next() {
let _ = foo.filter().next();
}
/// Checks implementation of `SEARCH_IS_SOME` lint.
#[rustfmt::skip]
fn search_is_some() {
let v = vec![3, 2, 1, 0, -1, -2, -3];
let y = &&42;
// Check `find().is_some()`, single-line case.
let _ = v.iter().find(|&x| *x < 0).is_some();
let _ = (0..1).find(|x| **y == *x).is_some(); // one dereference less
let _ = (0..1).find(|x| *x == 0).is_some();
let _ = v.iter().find(|x| **x == 0).is_some();
// Check `find().is_some()`, multi-line case.
let _ = v.iter().find(|&x| {
*x < 0
}
).is_some();
// Check `position().is_some()`, single-line case.
let _ = v.iter().position(|&x| x < 0).is_some();
// Check `position().is_some()`, multi-line case.
let _ = v.iter().position(|&x| {
x < 0
}
).is_some();
// Check `rposition().is_some()`, single-line case.
let _ = v.iter().rposition(|&x| x < 0).is_some();
// Check `rposition().is_some()`, multi-line case.
let _ = v.iter().rposition(|&x| {
x < 0
}
).is_some();
// Check that we don't lint if the caller is not an `Iterator`.
let foo = IteratorFalsePositives { foo: 0 };
let _ = foo.find().is_some();
let _ = foo.position().is_some();
let _ = foo.rposition().is_some();
}
fn main() {
filter_next();
search_is_some();
}

70
tests/ui/methods.stderr
View File

@ -20,73 +20,5 @@ LL | | ).next();
|
= note: `-D clippy::filter-next` implied by `-D warnings`
error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:143:22
|
LL | let _ = v.iter().find(|&x| *x < 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|x| *x < 0)`
|
= note: `-D clippy::search-is-some` implied by `-D warnings`
error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:144:20
|
LL | let _ = (0..1).find(|x| **y == *x).is_some(); // one dereference less
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|x| **y == x)`
error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:145:20
|
LL | let _ = (0..1).find(|x| *x == 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|x| x == 0)`
error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:146:22
|
LL | let _ = v.iter().find(|x| **x == 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|x| *x == 0)`
error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:149:13
|
LL | let _ = v.iter().find(|&x| {
| _____________^
LL | | *x < 0
LL | | }
LL | | ).is_some();
| |______________________________^
error: called `is_some()` after searching an `Iterator` with position. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:155:22
|
LL | let _ = v.iter().position(|&x| x < 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|&x| x < 0)`
error: called `is_some()` after searching an `Iterator` with position. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:158:13
|
LL | let _ = v.iter().position(|&x| {
| _____________^
LL | | x < 0
LL | | }
LL | | ).is_some();
| |______________________________^
error: called `is_some()` after searching an `Iterator` with rposition. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:164:22
|
LL | let _ = v.iter().rposition(|&x| x < 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|&x| x < 0)`
error: called `is_some()` after searching an `Iterator` with rposition. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:167:13
|
LL | let _ = v.iter().rposition(|&x| {
| _____________^
LL | | x < 0
LL | | }
LL | | ).is_some();
| |______________________________^
error: aborting due to 11 previous errors
error: aborting due to 2 previous errors

38
tests/ui/search_is_some.rs Normal file
View File

@ -0,0 +1,38 @@
// aux-build:option_helpers.rs
extern crate option_helpers;
use option_helpers::IteratorFalsePositives;
#[warn(clippy::search_is_some)]
#[rustfmt::skip]
fn main() {
let v = vec![3, 2, 1, 0, -1, -2, -3];
let y = &&42;
// Check `find().is_some()`, multi-line case.
let _ = v.iter().find(|&x| {
*x < 0
}
).is_some();
// Check `position().is_some()`, multi-line case.
let _ = v.iter().position(|&x| {
x < 0
}
).is_some();
// Check `rposition().is_some()`, multi-line case.
let _ = v.iter().rposition(|&x| {
x < 0
}
).is_some();
// Check that we don't lint if the caller is not an `Iterator` or string
let falsepos = IteratorFalsePositives { foo: 0 };
let _ = falsepos.find().is_some();
let _ = falsepos.position().is_some();
let _ = falsepos.rposition().is_some();
// check that we don't lint if `find()` is called with
// `Pattern` that is not a string
let _ = "hello world".find(|c: char| c == 'o' || c == 'l').is_some();
}

39
tests/ui/search_is_some.stderr Normal file
View File

@ -0,0 +1,39 @@
error: called `is_some()` after searching an `Iterator` with `find`
--> $DIR/search_is_some.rs:13:13
|
LL | let _ = v.iter().find(|&x| {
| _____________^
LL | | *x < 0
LL | | }
LL | | ).is_some();
| |______________________________^
|
= note: `-D clippy::search-is-some` implied by `-D warnings`
= help: this is more succinctly expressed by calling `any()`
error: called `is_some()` after searching an `Iterator` with `position`
--> $DIR/search_is_some.rs:19:13
|
LL | let _ = v.iter().position(|&x| {
| _____________^
LL | | x < 0
LL | | }
LL | | ).is_some();
| |______________________________^
|
= help: this is more succinctly expressed by calling `any()`
error: called `is_some()` after searching an `Iterator` with `rposition`
--> $DIR/search_is_some.rs:25:13
|
LL | let _ = v.iter().rposition(|&x| {
| _____________^
LL | | x < 0
LL | | }
LL | | ).is_some();
| |______________________________^
|
= help: this is more succinctly expressed by calling `any()`
error: aborting due to 3 previous errors

35
tests/ui/search_is_some_fixable.fixed Normal file
View File

@ -0,0 +1,35 @@
// run-rustfix
#![warn(clippy::search_is_some)]
fn main() {
let v = vec![3, 2, 1, 0, -1, -2, -3];
let y = &&42;
// Check `find().is_some()`, single-line case.
let _ = v.iter().any(|x| *x < 0);
let _ = (0..1).any(|x| **y == x); // one dereference less
let _ = (0..1).any(|x| x == 0);
let _ = v.iter().any(|x| *x == 0);
// Check `position().is_some()`, single-line case.
let _ = v.iter().any(|&x| x < 0);
// Check `rposition().is_some()`, single-line case.
let _ = v.iter().any(|&x| x < 0);
let s1 = String::from("hello world");
let s2 = String::from("world");
// caller of `find()` is a `&`static str`
let _ = "hello world".contains("world");
let _ = "hello world".contains(&s2);
let _ = "hello world".contains(&s2[2..]);
// caller of `find()` is a `String`
let _ = s1.contains("world");
let _ = s1.contains(&s2);
let _ = s1.contains(&s2[2..]);
// caller of `find()` is slice of `String`
let _ = s1[2..].contains("world");
let _ = s1[2..].contains(&s2);
let _ = s1[2..].contains(&s2[2..]);
}

35
tests/ui/search_is_some_fixable.rs Normal file
View File

@ -0,0 +1,35 @@
// run-rustfix
#![warn(clippy::search_is_some)]
fn main() {
let v = vec![3, 2, 1, 0, -1, -2, -3];
let y = &&42;
// Check `find().is_some()`, single-line case.
let _ = v.iter().find(|&x| *x < 0).is_some();
let _ = (0..1).find(|x| **y == *x).is_some(); // one dereference less
let _ = (0..1).find(|x| *x == 0).is_some();
let _ = v.iter().find(|x| **x == 0).is_some();
// Check `position().is_some()`, single-line case.
let _ = v.iter().position(|&x| x < 0).is_some();
// Check `rposition().is_some()`, single-line case.
let _ = v.iter().rposition(|&x| x < 0).is_some();
let s1 = String::from("hello world");
let s2 = String::from("world");
// caller of `find()` is a `&`static str`
let _ = "hello world".find("world").is_some();
let _ = "hello world".find(&s2).is_some();
let _ = "hello world".find(&s2[2..]).is_some();
// caller of `find()` is a `String`
let _ = s1.find("world").is_some();
let _ = s1.find(&s2).is_some();
let _ = s1.find(&s2[2..]).is_some();
// caller of `find()` is slice of `String`
let _ = s1[2..].find("world").is_some();
let _ = s1[2..].find(&s2).is_some();
let _ = s1[2..].find(&s2[2..]).is_some();
}

94
tests/ui/search_is_some_fixable.stderr Normal file
View File

@ -0,0 +1,94 @@
error: called `is_some()` after searching an `Iterator` with `find`
--> $DIR/search_is_some_fixable.rs:10:22
|
LL | let _ = v.iter().find(|&x| *x < 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `any()` instead: `any(|x| *x < 0)`
|
= note: `-D clippy::search-is-some` implied by `-D warnings`
error: called `is_some()` after searching an `Iterator` with `find`
--> $DIR/search_is_some_fixable.rs:11:20
|
LL | let _ = (0..1).find(|x| **y == *x).is_some(); // one dereference less
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `any()` instead: `any(|x| **y == x)`
error: called `is_some()` after searching an `Iterator` with `find`
--> $DIR/search_is_some_fixable.rs:12:20
|
LL | let _ = (0..1).find(|x| *x == 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `any()` instead: `any(|x| x == 0)`
error: called `is_some()` after searching an `Iterator` with `find`
--> $DIR/search_is_some_fixable.rs:13:22
|
LL | let _ = v.iter().find(|x| **x == 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `any()` instead: `any(|x| *x == 0)`
error: called `is_some()` after searching an `Iterator` with `position`
--> $DIR/search_is_some_fixable.rs:16:22
|
LL | let _ = v.iter().position(|&x| x < 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `any()` instead: `any(|&x| x < 0)`
error: called `is_some()` after searching an `Iterator` with `rposition`
--> $DIR/search_is_some_fixable.rs:19:22
|
LL | let _ = v.iter().rposition(|&x| x < 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `any()` instead: `any(|&x| x < 0)`
error: called `is_some()` after calling `find()` on a string
--> $DIR/search_is_some_fixable.rs:24:27
|
LL | let _ = "hello world".find("world").is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^ help: use `contains()` instead: `contains("world")`
error: called `is_some()` after calling `find()` on a string
--> $DIR/search_is_some_fixable.rs:25:27
|
LL | let _ = "hello world".find(&s2).is_some();
| ^^^^^^^^^^^^^^^^^^^ help: use `contains()` instead: `contains(&s2)`
error: called `is_some()` after calling `find()` on a string
--> $DIR/search_is_some_fixable.rs:26:27
|
LL | let _ = "hello world".find(&s2[2..]).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: use `contains()` instead: `contains(&s2[2..])`
error: called `is_some()` after calling `find()` on a string
--> $DIR/search_is_some_fixable.rs:28:16
|
LL | let _ = s1.find("world").is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^ help: use `contains()` instead: `contains("world")`
error: called `is_some()` after calling `find()` on a string
--> $DIR/search_is_some_fixable.rs:29:16
|
LL | let _ = s1.find(&s2).is_some();
| ^^^^^^^^^^^^^^^^^^^ help: use `contains()` instead: `contains(&s2)`
error: called `is_some()` after calling `find()` on a string
--> $DIR/search_is_some_fixable.rs:30:16
|
LL | let _ = s1.find(&s2[2..]).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: use `contains()` instead: `contains(&s2[2..])`
error: called `is_some()` after calling `find()` on a string
--> $DIR/search_is_some_fixable.rs:32:21
|
LL | let _ = s1[2..].find("world").is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^ help: use `contains()` instead: `contains("world")`
error: called `is_some()` after calling `find()` on a string
--> $DIR/search_is_some_fixable.rs:33:21
|
LL | let _ = s1[2..].find(&s2).is_some();
| ^^^^^^^^^^^^^^^^^^^ help: use `contains()` instead: `contains(&s2)`
error: called `is_some()` after calling `find()` on a string
--> $DIR/search_is_some_fixable.rs:34:21
|
LL | let _ = s1[2..].find(&s2[2..]).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: use `contains()` instead: `contains(&s2[2..])`
error: aborting due to 15 previous errors