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fix: remove unnecessary filter_map usages #13548

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Merged
merged 3 commits into from
Oct 27, 2024
Merged

fix: remove unnecessary filter_map usages #13548

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11162d1
fix: remove unnecessary unfilter_map usages
wowinter13 Oct 14, 2024
40cb24f
fix: simplify suggestion
wowinter13 Oct 15, 2024
ad002ea
fix: linter
wowinter13 Oct 15, 2024
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31 changes: 26 additions & 5 deletions clippy_lints/src/methods/unnecessary_filter_map.rs
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Original file line number Diff line number Diff line change
@@ -1,13 +1,15 @@
use super::utils::clone_or_copy_needed;
use clippy_utils::diagnostics::span_lint;
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::ty::is_copy;
use clippy_utils::usage::mutated_variables;
use clippy_utils::visitors::{Descend, for_each_expr_without_closures};
use clippy_utils::{is_res_lang_ctor, is_trait_method, path_res, path_to_local_id};
use clippy_utils::{MaybePath, is_res_lang_ctor, is_trait_method, path_res, path_to_local_id};
use core::ops::ControlFlow;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_hir::LangItem::{OptionNone, OptionSome};
use rustc_lint::LateContext;
use rustc_middle::query::Key;
use rustc_middle::ty;
use rustc_span::sym;

Expand Down Expand Up @@ -36,9 +38,25 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>, a
ControlFlow::Continue(Descend::Yes)
}
});

let in_ty = cx.typeck_results().node_type(body.params[0].hir_id);
let sugg = if !found_filtering {
// Check if the closure is .filter_map(|x| Some(x))
if name == "filter_map"
&& let hir::ExprKind::Call(expr, args) = body.value.kind
&& is_res_lang_ctor(cx, path_res(cx, expr), OptionSome)
&& arg_id.ty_def_id() == args[0].hir_id().ty_def_id()
&& let hir::ExprKind::Path(_) = args[0].kind
{
span_lint_and_sugg(
cx,
UNNECESSARY_FILTER_MAP,
expr.span,
format!("{name} is unnecessary"),
"try removing the filter_map",
String::new(),
Applicability::MaybeIncorrect,
);
}
if name == "filter_map" { "map" } else { "map(..).next()" }
} else if !found_mapping && !mutates_arg && (!clone_or_copy_needed || is_copy(cx, in_ty)) {
match cx.typeck_results().expr_ty(body.value).kind() {
Expand All @@ -52,15 +70,18 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>, a
} else {
return;
};
span_lint(
span_lint_and_sugg(
cx,
if name == "filter_map" {
UNNECESSARY_FILTER_MAP
} else {
UNNECESSARY_FIND_MAP
},
expr.span,
format!("this `.{name}` can be written more simply using `.{sugg}`"),
format!("this `.{name}` can be written more simply"),
"try instead",
sugg.to_string(),
Applicability::MaybeIncorrect,
);
}
}
Expand Down
13 changes: 9 additions & 4 deletions tests/ui/unnecessary_filter_map.rs
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Original file line number Diff line number Diff line change
@@ -1,26 +1,31 @@
//@no-rustfix
#![allow(dead_code)]

fn main() {
let _ = (0..4).filter_map(|x| if x > 1 { Some(x) } else { None });
//~^ ERROR: this `.filter_map` can be written more simply using `.filter`
//~^ ERROR: this `.filter_map` can be written more simply
//~| NOTE: `-D clippy::unnecessary-filter-map` implied by `-D warnings`
let _ = (0..4).filter_map(|x| {
//~^ ERROR: this `.filter_map` can be written more simply using `.filter`
//~^ ERROR: this `.filter_map` can be written more simply
if x > 1 {
return Some(x);
};
None
});
let _ = (0..4).filter_map(|x| match x {
//~^ ERROR: this `.filter_map` can be written more simply using `.filter`
//~^ ERROR: this `.filter_map` can be written more simply
0 | 1 => None,
_ => Some(x),
});

let _ = (0..4).filter_map(|x| Some(x + 1));
//~^ ERROR: this `.filter_map` can be written more simply using `.map`
//~^ ERROR: this `.filter_map` can be written more simply

let _ = (0..4).filter_map(i32::checked_abs);

let _ = (0..4).filter_map(Some);

let _ = vec![Some(10), None].into_iter().filter_map(|x| Some(x));
}

fn filter_map_none_changes_item_type() -> impl Iterator<Item = bool> {
Expand Down
53 changes: 37 additions & 16 deletions tests/ui/unnecessary_filter_map.stderr
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Original file line number Diff line number Diff line change
@@ -1,14 +1,14 @@
error: this `.filter_map` can be written more simply using `.filter`
--> tests/ui/unnecessary_filter_map.rs:4:13
error: this `.filter_map` can be written more simply
--> tests/ui/unnecessary_filter_map.rs:5:13
|
LL | let _ = (0..4).filter_map(|x| if x > 1 { Some(x) } else { None });
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try instead: `filter`
|
= note: `-D clippy::unnecessary-filter-map` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::unnecessary_filter_map)]`

error: this `.filter_map` can be written more simply using `.filter`
--> tests/ui/unnecessary_filter_map.rs:7:13
error: this `.filter_map` can be written more simply
--> tests/ui/unnecessary_filter_map.rs:8:13
|
LL | let _ = (0..4).filter_map(|x| {
| _____________^
Expand All @@ -18,30 +18,51 @@ LL | | return Some(x);
LL | | };
LL | | None
LL | | });
| |______^
| |______^ help: try instead: `filter`

error: this `.filter_map` can be written more simply using `.filter`
--> tests/ui/unnecessary_filter_map.rs:14:13
error: this `.filter_map` can be written more simply
--> tests/ui/unnecessary_filter_map.rs:15:13
|
LL | let _ = (0..4).filter_map(|x| match x {
| _____________^
LL | |
LL | | 0 | 1 => None,
LL | | _ => Some(x),
LL | | });
| |______^
| |______^ help: try instead: `filter`

error: this `.filter_map` can be written more simply using `.map`
--> tests/ui/unnecessary_filter_map.rs:20:13
error: this `.filter_map` can be written more simply
--> tests/ui/unnecessary_filter_map.rs:21:13
|
LL | let _ = (0..4).filter_map(|x| Some(x + 1));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try instead: `map`

error: this `.filter_map` can be written more simply using `.filter`
--> tests/ui/unnecessary_filter_map.rs:160:14
error: redundant closure
--> tests/ui/unnecessary_filter_map.rs:28:57
|
LL | let _ = vec![Some(10), None].into_iter().filter_map(|x| Some(x));
| ^^^^^^^^^^^ help: replace the closure with the function itself: `Some`
|
= note: `-D clippy::redundant-closure` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::redundant_closure)]`

error: filter_map is unnecessary
--> tests/ui/unnecessary_filter_map.rs:28:61
|
LL | let _ = vec![Some(10), None].into_iter().filter_map(|x| Some(x));
| ^^^^ help: try removing the filter_map

error: this `.filter_map` can be written more simply
--> tests/ui/unnecessary_filter_map.rs:28:13
|
LL | let _ = vec![Some(10), None].into_iter().filter_map(|x| Some(x));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try instead: `map`

error: this `.filter_map` can be written more simply
--> tests/ui/unnecessary_filter_map.rs:165:14
|
LL | let _x = std::iter::once(1).filter_map(|n| (n > 1).then_some(n));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try instead: `filter`

error: aborting due to 5 previous errors
error: aborting due to 8 previous errors

9 changes: 5 additions & 4 deletions tests/ui/unnecessary_find_map.rs
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Original file line number Diff line number Diff line change
@@ -1,24 +1,25 @@
//@no-rustfix
#![allow(dead_code)]

fn main() {
let _ = (0..4).find_map(|x| if x > 1 { Some(x) } else { None });
//~^ ERROR: this `.find_map` can be written more simply using `.find`
//~^ ERROR: this `.find_map` can be written more simply
//~| NOTE: `-D clippy::unnecessary-find-map` implied by `-D warnings`
let _ = (0..4).find_map(|x| {
//~^ ERROR: this `.find_map` can be written more simply using `.find`
//~^ ERROR: this `.find_map` can be written more simply
if x > 1 {
return Some(x);
};
None
});
let _ = (0..4).find_map(|x| match x {
//~^ ERROR: this `.find_map` can be written more simply using `.find`
//~^ ERROR: this `.find_map` can be written more simply
0 | 1 => None,
_ => Some(x),
});

let _ = (0..4).find_map(|x| Some(x + 1));
//~^ ERROR: this `.find_map` can be written more simply using `.map(..).next()`
//~^ ERROR: this `.find_map` can be written more simply

let _ = (0..4).find_map(i32::checked_abs);
}
Expand Down
30 changes: 15 additions & 15 deletions tests/ui/unnecessary_find_map.stderr
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Original file line number Diff line number Diff line change
@@ -1,14 +1,14 @@
error: this `.find_map` can be written more simply using `.find`
--> tests/ui/unnecessary_find_map.rs:4:13
error: this `.find_map` can be written more simply
--> tests/ui/unnecessary_find_map.rs:5:13
|
LL | let _ = (0..4).find_map(|x| if x > 1 { Some(x) } else { None });
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try instead: `find`
|
= note: `-D clippy::unnecessary-find-map` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::unnecessary_find_map)]`

error: this `.find_map` can be written more simply using `.find`
--> tests/ui/unnecessary_find_map.rs:7:13
error: this `.find_map` can be written more simply
--> tests/ui/unnecessary_find_map.rs:8:13
|
LL | let _ = (0..4).find_map(|x| {
| _____________^
Expand All @@ -18,30 +18,30 @@ LL | | return Some(x);
LL | | };
LL | | None
LL | | });
| |______^
| |______^ help: try instead: `find`

error: this `.find_map` can be written more simply using `.find`
--> tests/ui/unnecessary_find_map.rs:14:13
error: this `.find_map` can be written more simply
--> tests/ui/unnecessary_find_map.rs:15:13
|
LL | let _ = (0..4).find_map(|x| match x {
| _____________^
LL | |
LL | | 0 | 1 => None,
LL | | _ => Some(x),
LL | | });
| |______^
| |______^ help: try instead: `find`

error: this `.find_map` can be written more simply using `.map(..).next()`
--> tests/ui/unnecessary_find_map.rs:20:13
error: this `.find_map` can be written more simply
--> tests/ui/unnecessary_find_map.rs:21:13
|
LL | let _ = (0..4).find_map(|x| Some(x + 1));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try instead: `map(..).next()`

error: this `.find_map` can be written more simply using `.find`
--> tests/ui/unnecessary_find_map.rs:32:14
error: this `.find_map` can be written more simply
--> tests/ui/unnecessary_find_map.rs:33:14
|
LL | let _x = std::iter::once(1).find_map(|n| (n > 1).then_some(n));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try instead: `find`

error: aborting due to 5 previous errors