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Reuse is_expr_identity_function for filter_map_identity

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This commit is contained in:
xFrednet 2021-06-07 23:31:17 +02:00
parent bb3b58cfcc
commit 9e54ce865c
4 changed files with 29 additions and 35 deletions
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24
clippy_lints/src/methods/filter_map_identity.rs
View file

@ -1,6 +1,5 @@
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::{is_expr_path_def_path, is_trait_method, path_to_local_id, paths};
use if_chain::if_chain;
use clippy_utils::{is_expr_identity_function, is_trait_method};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
@ -9,32 +8,15 @@ use rustc_span::{source_map::Span, sym};
use super::FILTER_MAP_IDENTITY;
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, filter_map_arg: &hir::Expr<'_>, filter_map_span: Span) {
if is_trait_method(cx, expr, sym::Iterator) {
let apply_lint = |message: &str| {
if is_trait_method(cx, expr, sym::Iterator) && is_expr_identity_function(cx, filter_map_arg) {
span_lint_and_sugg(
cx,
FILTER_MAP_IDENTITY,
filter_map_span.with_hi(expr.span.hi()),
message,
"use of `filter_map` with an identity function",
"try",
"flatten()".to_string(),
Applicability::MachineApplicable,
);
};
if_chain! {
if let hir::ExprKind::Closure(_, _, body_id, _, _) = filter_map_arg.kind;
let body = cx.tcx.hir().body(body_id);
if let hir::PatKind::Binding(_, binding_id, ..) = body.params[0].pat.kind;
if path_to_local_id(&body.value, binding_id);
then {
apply_lint("called `filter_map(|x| x)` on an `Iterator`");
}
}
if is_expr_path_def_path(cx, filter_map_arg, &paths::CONVERT_IDENTITY) {
apply_lint("called `filter_map(std::convert::identity)` on an `Iterator`");
}
}
}

5
tests/ui/filter_map_identity.fixed
View file

@ -1,6 +1,6 @@
// run-rustfix
#![allow(unused_imports)]
#![allow(unused_imports, clippy::needless_return)]
#![warn(clippy::filter_map_identity)]
fn main() {
@ -13,4 +13,7 @@ fn main() {
use std::convert::identity;
let iterator = vec![Some(1), None, Some(2)].into_iter();
let _ = iterator.flatten();
let iterator = vec![Some(1), None, Some(2)].into_iter();
let _ = iterator.flatten();
}

5
tests/ui/filter_map_identity.rs
View file

@ -1,6 +1,6 @@
// run-rustfix
#![allow(unused_imports)]
#![allow(unused_imports, clippy::needless_return)]
#![warn(clippy::filter_map_identity)]
fn main() {
@ -13,4 +13,7 @@ fn main() {
use std::convert::identity;
let iterator = vec![Some(1), None, Some(2)].into_iter();
let _ = iterator.filter_map(identity);
let iterator = vec![Some(1), None, Some(2)].into_iter();
let _ = iterator.filter_map(|x| return x);
}

14
tests/ui/filter_map_identity.stderr
View file

@ -1,4 +1,4 @@
error: called `filter_map(|x| x)` on an `Iterator`
error: use of `filter_map` with an identity function
--> $DIR/filter_map_identity.rs:8:22
|
LL | let _ = iterator.filter_map(|x| x);
@ -6,17 +6,23 @@ LL | let _ = iterator.filter_map(|x| x);
|
= note: `-D clippy::filter-map-identity` implied by `-D warnings`
error: called `filter_map(std::convert::identity)` on an `Iterator`
error: use of `filter_map` with an identity function
--> $DIR/filter_map_identity.rs:11:22
|
LL | let _ = iterator.filter_map(std::convert::identity);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `flatten()`
error: called `filter_map(std::convert::identity)` on an `Iterator`
error: use of `filter_map` with an identity function
--> $DIR/filter_map_identity.rs:15:22
|
LL | let _ = iterator.filter_map(identity);
| ^^^^^^^^^^^^^^^^^^^^ help: try: `flatten()`
error: aborting due to 3 previous errors
error: use of `filter_map` with an identity function
--> $DIR/filter_map_identity.rs:18:22
|
LL | let _ = iterator.filter_map(|x| return x);
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `flatten()`
error: aborting due to 4 previous errors