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Reuse is_expr_identity_function for flat_map_identity

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This commit is contained in:
xFrednet
2021-06-07 23:10:42 +02:00
parent 967d815a42
commit bb3b58cfcc
4 changed files with 28 additions and 38 deletions
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44
clippy_lints/src/methods/flat_map_identity.rs
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@@ -1,6 +1,5 @@
use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::{is_expr_path_def_path, is_trait_method, paths}; use clippy_utils::{is_expr_identity_function, is_trait_method};
use if_chain::if_chain;
use rustc_errors::Applicability; use rustc_errors::Applicability;
use rustc_hir as hir; use rustc_hir as hir;
use rustc_lint::LateContext; use rustc_lint::LateContext;
@@ -15,36 +14,15 @@ pub(super) fn check<'tcx>(
flat_map_arg: &'tcx hir::Expr<'_>, flat_map_arg: &'tcx hir::Expr<'_>,
flat_map_span: Span, flat_map_span: Span,
) { ) {
if is_trait_method(cx, expr, sym::Iterator) { if is_trait_method(cx, expr, sym::Iterator) && is_expr_identity_function(cx, flat_map_arg) {
let apply_lint = |message: &str| { span_lint_and_sugg(
span_lint_and_sugg( cx,
cx, FLAT_MAP_IDENTITY,
FLAT_MAP_IDENTITY, flat_map_span.with_hi(expr.span.hi()),
flat_map_span.with_hi(expr.span.hi()), "use of `flat_map` with an identity function",
message, "try",
"try", "flatten()".to_string(),
"flatten()".to_string(), Applicability::MachineApplicable,
Applicability::MachineApplicable, );
);
};
if_chain! {
if let hir::ExprKind::Closure(_, _, body_id, _, _) = flat_map_arg.kind;
let body = cx.tcx.hir().body(body_id);
if let hir::PatKind::Binding(_, _, binding_ident, _) = body.params[0].pat.kind;
if let hir::ExprKind::Path(hir::QPath::Resolved(_, path)) = body.value.kind;
if path.segments.len() == 1;
if path.segments[0].ident.name == binding_ident.name;
then {
apply_lint("called `flat_map(|x| x)` on an `Iterator`");
}
}
if is_expr_path_def_path(cx, flat_map_arg, &paths::CONVERT_IDENTITY) {
apply_lint("called `flat_map(std::convert::identity)` on an `Iterator`");
}
} }
} }

5
tests/ui/flat_map_identity.fixed
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@@ -1,6 +1,6 @@
// run-rustfix // run-rustfix
#![allow(unused_imports)] #![allow(unused_imports, clippy::needless_return)]
#![warn(clippy::flat_map_identity)] #![warn(clippy::flat_map_identity)]
use std::convert; use std::convert;
@@ -11,4 +11,7 @@ fn main() {
let iterator = [[0, 1], [2, 3], [4, 5]].iter(); let iterator = [[0, 1], [2, 3], [4, 5]].iter();
let _ = iterator.flatten(); let _ = iterator.flatten();
let iterator = [[0, 1], [2, 3], [4, 5]].iter();
let _ = iterator.flatten();
} }

5
tests/ui/flat_map_identity.rs
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@@ -1,6 +1,6 @@
// run-rustfix // run-rustfix
#![allow(unused_imports)] #![allow(unused_imports, clippy::needless_return)]
#![warn(clippy::flat_map_identity)] #![warn(clippy::flat_map_identity)]
use std::convert; use std::convert;
@@ -11,4 +11,7 @@ fn main() {
let iterator = [[0, 1], [2, 3], [4, 5]].iter(); let iterator = [[0, 1], [2, 3], [4, 5]].iter();
let _ = iterator.flat_map(convert::identity); let _ = iterator.flat_map(convert::identity);
let iterator = [[0, 1], [2, 3], [4, 5]].iter();
let _ = iterator.flat_map(|x| return x);
} }

12
tests/ui/flat_map_identity.stderr
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@@ -1,4 +1,4 @@
error: called `flat_map(|x| x)` on an `Iterator` error: use of `flat_map` with an identity function
--> $DIR/flat_map_identity.rs:10:22 --> $DIR/flat_map_identity.rs:10:22
| |
LL | let _ = iterator.flat_map(|x| x); LL | let _ = iterator.flat_map(|x| x);
@@ -6,11 +6,17 @@ LL | let _ = iterator.flat_map(|x| x);
| |
= note: `-D clippy::flat-map-identity` implied by `-D warnings` = note: `-D clippy::flat-map-identity` implied by `-D warnings`
error: called `flat_map(std::convert::identity)` on an `Iterator` error: use of `flat_map` with an identity function
--> $DIR/flat_map_identity.rs:13:22 --> $DIR/flat_map_identity.rs:13:22
| |
LL | let _ = iterator.flat_map(convert::identity); LL | let _ = iterator.flat_map(convert::identity);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `flatten()` | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `flatten()`
error: aborting due to 2 previous errors error: use of `flat_map` with an identity function
--> $DIR/flat_map_identity.rs:16:22
|
LL | let _ = iterator.flat_map(|x| return x);
| ^^^^^^^^^^^^^^^^^^^^^^ help: try: `flatten()`
error: aborting due to 3 previous errors