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[filter_map_bool_then]: peel as many refs as needed

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y21 2023-09-16 14:14:51 +02:00
parent f54275f20f
commit 860e800fa0
4 changed files with 40 additions and 5 deletions
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15
clippy_lints/src/methods/filter_map_bool_then.rs
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@ -2,13 +2,13 @@ use super::FILTER_MAP_BOOL_THEN;
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::paths::BOOL_THEN;
use clippy_utils::source::snippet_opt;
use clippy_utils::ty::is_copy;
use clippy_utils::ty::{is_copy, peel_mid_ty_refs_is_mutable};
use clippy_utils::{is_from_proc_macro, is_trait_method, match_def_path, peel_blocks};
use rustc_errors::Applicability;
use rustc_hir::{Expr, ExprKind};
use rustc_lint::{LateContext, LintContext};
use rustc_middle::lint::in_external_macro;
use rustc_middle::ty::{self, Binder};
use rustc_middle::ty::Binder;
use rustc_span::{sym, Span};
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, arg: &Expr<'_>, call_span: Span) {
@ -36,7 +36,11 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, arg: &
&& let Some(def_id) = cx.typeck_results().type_dependent_def_id(value.hir_id)
&& match_def_path(cx, def_id, &BOOL_THEN)
&& !is_from_proc_macro(cx, expr)
&& let ref_bool = matches!(cx.typeck_results().expr_ty(recv).kind(), ty::Ref(..))
// Peel all refs (e.g. `&&&&mut &&&bool` -> `bool`) and get its count so we can suggest the exact
// amount of derefs to get to the bool in the filter.
// `peel_mid_ty_refs` alone doesn't handle mutable reference, so we use `_is_mutable`
// instead which counts them too and just ignore the resulting mutability
&& let (_, needed_derefs, _) = peel_mid_ty_refs_is_mutable(cx.typeck_results().expr_ty(recv))
&& let Some(param_snippet) = snippet_opt(cx, param.span)
&& let Some(filter) = snippet_opt(cx, recv.span)
&& let Some(map) = snippet_opt(cx, then_body.span)
@ -47,7 +51,10 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, arg: &
call_span,
"usage of `bool::then` in `filter_map`",
"use `filter` then `map` instead",
format!("filter(|&{param_snippet}| {}{filter}).map(|{param_snippet}| {map})", if ref_bool { "*" } else { "" }),
format!(
"filter(|&{param_snippet}| {derefs}{filter}).map(|{param_snippet}| {map})",
derefs="*".repeat(needed_derefs)
),
Applicability::MachineApplicable,
);
}

8
tests/ui/filter_map_bool_then.fixed
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@ -59,4 +59,12 @@ fn issue11309<'a>(iter: impl Iterator<Item = (&'a str, &'a str)>) -> Vec<&'a str
fn issue11503() {
let bools: &[bool] = &[true, false, false, true];
let _: Vec<usize> = bools.iter().enumerate().filter(|&(i, b)| *b).map(|(i, b)| i).collect();
// Need to insert multiple derefs if there is more than one layer of references
let bools: &[&&bool] = &[&&true, &&false, &&false, &&true];
let _: Vec<usize> = bools.iter().enumerate().filter(|&(i, b)| ***b).map(|(i, b)| i).collect();
// Should also suggest derefs when going through a mutable reference
let bools: &[&mut bool] = &[&mut true];
let _: Vec<usize> = bools.iter().enumerate().filter(|&(i, b)| **b).map(|(i, b)| i).collect();
}

8
tests/ui/filter_map_bool_then.rs
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@ -59,4 +59,12 @@ fn issue11309<'a>(iter: impl Iterator<Item = (&'a str, &'a str)>) -> Vec<&'a str
fn issue11503() {
let bools: &[bool] = &[true, false, false, true];
let _: Vec<usize> = bools.iter().enumerate().filter_map(|(i, b)| b.then(|| i)).collect();
// Need to insert multiple derefs if there is more than one layer of references
let bools: &[&&bool] = &[&&true, &&false, &&false, &&true];
let _: Vec<usize> = bools.iter().enumerate().filter_map(|(i, b)| b.then(|| i)).collect();
// Should also suggest derefs when going through a mutable reference
let bools: &[&mut bool] = &[&mut true];
let _: Vec<usize> = bools.iter().enumerate().filter_map(|(i, b)| b.then(|| i)).collect();
}

14
tests/ui/filter_map_bool_then.stderr
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@ -43,5 +43,17 @@ error: usage of `bool::then` in `filter_map`
LL | let _: Vec<usize> = bools.iter().enumerate().filter_map(|(i, b)| b.then(|| i)).collect();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `filter` then `map` instead: `filter(|&(i, b)| *b).map(|(i, b)| i)`
error: aborting due to 7 previous errors
error: usage of `bool::then` in `filter_map`
--> $DIR/filter_map_bool_then.rs:65:50
|
LL | let _: Vec<usize> = bools.iter().enumerate().filter_map(|(i, b)| b.then(|| i)).collect();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `filter` then `map` instead: `filter(|&(i, b)| ***b).map(|(i, b)| i)`
error: usage of `bool::then` in `filter_map`
--> $DIR/filter_map_bool_then.rs:69:50
|
LL | let _: Vec<usize> = bools.iter().enumerate().filter_map(|(i, b)| b.then(|| i)).collect();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `filter` then `map` instead: `filter(|&(i, b)| **b).map(|(i, b)| i)`
error: aborting due to 9 previous errors