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search_is_some: check also when search is none

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This commit is contained in:
Mateusz Gacek 2021-03-20 14:30:45 +01:00
parent 1d3c539fbb
commit 2ffee89b75
7 changed files with 359 additions and 48 deletions
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57
clippy_lints/src/methods/mod.rs
View file

@ -588,26 +588,31 @@ declare_clippy_lint! {
declare_clippy_lint! {
/// **What it does:** Checks for an iterator or string search (such as `find()`,
/// `position()`, or `rposition()`) followed by a call to `is_some()`.
/// `position()`, or `rposition()`) followed by a call to `is_some()` or `is_none()`.
///
/// **Why is this bad?** Readability, this can be written more concisely as
/// `_.any(_)` or `_.contains(_)`.
/// **Why is this bad?** Readability, this can be written more concisely as:
/// * `_.any(_)`, or `_.contains(_)` for `is_some()`,
/// * `!_.any(_)`, or `!_.contains(_)` for `is_none()`.
///
/// **Known problems:** None.
///
/// **Example:**
/// ```rust
/// # let vec = vec![1];
/// let vec = vec![1];
/// vec.iter().find(|x| **x == 0).is_some();
///
/// let _ = "hello world".find("world").is_none();
/// ```
/// Could be written as
/// ```rust
/// # let vec = vec![1];
/// let vec = vec![1];
/// vec.iter().any(|x| *x == 0);
///
/// let _ = !"hello world".contains("world");
/// ```
pub SEARCH_IS_SOME,
complexity,
"using an iterator or string search followed by `is_some()`, which is more succinctly expressed as a call to `any()` or `contains()`"
"using an iterator or string search followed by `is_some()` or `is_none()`, which is more succinctly expressed as a call to `any()` or `contains()` (with negation in case of `is_none()`)"
}
declare_clippy_lint! {
@ -1720,12 +1725,42 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
["flat_map", "filter_map"] => filter_map_flat_map::check(cx, expr, arg_lists[1], arg_lists[0]),
["flat_map", ..] => flat_map_identity::check(cx, expr, arg_lists[0], method_spans[0]),
["flatten", "map"] => map_flatten::check(cx, expr, arg_lists[1]),
["is_some", "find"] => search_is_some::check(cx, expr, "find", arg_lists[1], arg_lists[0], method_spans[1]),
["is_some", "position"] => {
search_is_some::check(cx, expr, "position", arg_lists[1], arg_lists[0], method_spans[1])
[option_check_method, "find"] if "is_some" == *option_check_method || "is_none" == *option_check_method => {
search_is_some::check(
cx,
expr,
"find",
option_check_method,
arg_lists[1],
arg_lists[0],
method_spans[1],
)
},
["is_some", "rposition"] => {
search_is_some::check(cx, expr, "rposition", arg_lists[1], arg_lists[0], method_spans[1])
[option_check_method, "position"]
if "is_some" == *option_check_method || "is_none" == *option_check_method =>
{
search_is_some::check(
cx,
expr,
"position",
option_check_method,
arg_lists[1],
arg_lists[0],
method_spans[1],
)
},
[option_check_method, "rposition"]
if "is_some" == *option_check_method || "is_none" == *option_check_method =>
{
search_is_some::check(
cx,
expr,
"rposition",
option_check_method,
arg_lists[1],
arg_lists[0],
method_spans[1],
)
},
["extend", ..] => string_extend_chars::check(cx, expr, arg_lists[0]),
["count", "into_iter"] => iter_count::check(cx, expr, &arg_lists[1], "into_iter"),

107
clippy_lints/src/methods/search_is_some.rs
View file

@ -14,11 +14,13 @@ use rustc_span::symbol::sym;
use super::SEARCH_IS_SOME;
/// lint searching an Iterator followed by `is_some()`
/// or calling `find()` on a string followed by `is_some()`
/// or calling `find()` on a string followed by `is_some()` or `is_none()`
#[allow(clippy::too_many_lines)]
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
search_method: &str,
option_check_method: &str,
search_args: &'tcx [hir::Expr<'_>],
is_some_args: &'tcx [hir::Expr<'_>],
method_span: Span,
@ -26,10 +28,9 @@ pub(super) fn check<'tcx>(
// lint if caller of search is an Iterator
if is_trait_method(cx, &is_some_args[0], sym::Iterator) {
let msg = format!(
"called `is_some()` after searching an `Iterator` with `{}`",
search_method
"called `{}()` after searching an `Iterator` with `{}`",
option_check_method, 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()`
@ -53,20 +54,49 @@ pub(super) fn check<'tcx>(
}
};
// add note if not multi-line
span_lint_and_sugg(
cx,
SEARCH_IS_SOME,
method_span.with_hi(expr.span.hi()),
&msg,
"use `any()` instead",
format!(
"any({})",
any_search_snippet.as_ref().map_or(&*search_snippet, String::as_str)
),
Applicability::MachineApplicable,
);
match option_check_method {
"is_some" => {
span_lint_and_sugg(
cx,
SEARCH_IS_SOME,
method_span.with_hi(expr.span.hi()),
&msg,
"use `any()` instead",
format!(
"any({})",
any_search_snippet.as_ref().map_or(&*search_snippet, String::as_str)
),
Applicability::MachineApplicable,
);
},
"is_none" => {
let iter = snippet(cx, search_args[0].span, "..");
span_lint_and_sugg(
cx,
SEARCH_IS_SOME,
expr.span,
&msg,
"use `!_.any()` instead",
format!(
"!{}.any({})",
iter,
any_search_snippet.as_ref().map_or(&*search_snippet, String::as_str)
),
Applicability::MachineApplicable,
);
},
_ => (),
}
} else {
span_lint_and_help(cx, SEARCH_IS_SOME, expr.span, &msg, None, hint);
let hint = format!(
"this is more succinctly expressed by calling `any()`{}",
if option_check_method == "is_none" {
" with negation"
} else {
""
}
);
span_lint_and_help(cx, SEARCH_IS_SOME, expr.span, &msg, None, &hint);
}
}
// lint if `find()` is called by `String` or `&str`
@ -83,18 +113,37 @@ pub(super) fn check<'tcx>(
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,
);
let msg = format!("called `{}()` after calling `find()` on a string", option_check_method);
match option_check_method {
"is_some" => {
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,
);
},
"is_none" => {
let string = snippet(cx, search_args[0].span, "..");
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,
expr.span,
&msg,
"use `!_.contains()` instead",
format!("!{}.contains({})", string, find_arg),
applicability,
);
},
_ => (),
}
}
}
}