From dbe2699321ad0173a3e0c136baf0a9c818b8206e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Iv=C3=A1n=20Ovejero?= <ivov.src@gmail.com>
Date: Sun, 21 Jun 2026 14:22:57 +0200
Subject: [PATCH] fix: relax length comparison lint to skip non-empty checks

---
 .../lints/ast_walk/checks/manual_is_empty.rs  | 14 +++-----
 tests/ui/lint/mod.rs                          | 32 ++++++++++++++++---
 .../manual_is_empty_greater_than_zero.snap    | 12 -------
 .../manual_is_empty_not_equals_zero.snap      | 12 -------
 4 files changed, 32 insertions(+), 38 deletions(-)
 delete mode 100644 tests/ui/lint/snapshots/manual_is_empty_greater_than_zero.snap
 delete mode 100644 tests/ui/lint/snapshots/manual_is_empty_not_equals_zero.snap

diff --git a/crates/passes/src/passes/lints/ast_walk/checks/manual_is_empty.rs b/crates/passes/src/passes/lints/ast_walk/checks/manual_is_empty.rs
index 32c40ef84..f86af9b07 100644
--- a/crates/passes/src/passes/lints/ast_walk/checks/manual_is_empty.rs
+++ b/crates/passes/src/passes/lints/ast_walk/checks/manual_is_empty.rs
@@ -39,21 +39,15 @@ pub fn check_manual_is_empty(expression: &Expression, ctx: &NodeCtx) {
         return;
     }
 
-    let negate = match operator {
-        Equal | LessThanOrEqual => false,
-        NotEqual | GreaterThan => true,
-        _ => return,
-    };
+    if !matches!(operator, Equal | LessThanOrEqual) {
+        return;
+    }
 
     let Some(receiver_text) = receiver.as_dotted_path() else {
         return;
     };
 
-    let replacement = if negate {
-        format!("!{receiver_text}.is_empty()")
-    } else {
-        format!("{receiver_text}.is_empty()")
-    };
+    let replacement = format!("{receiver_text}.is_empty()");
 
     ctx.sink
         .push(diagnostics::lint::manual_is_empty(span, &replacement));
diff --git a/tests/ui/lint/mod.rs b/tests/ui/lint/mod.rs
index 0e3c5a227..710eb0a22 100644
--- a/tests/ui/lint/mod.rs
+++ b/tests/ui/lint/mod.rs
@@ -844,8 +844,8 @@ fn main() {
 }
 
 #[test]
-fn manual_is_empty_not_equals_zero() {
-    assert_lint_snapshot!(
+fn manual_is_empty_not_equals_zero_no_warning() {
+    assert_no_lint_warnings!(
         r#"
 fn main() {
   let xs = [1, 2, 3]
@@ -856,8 +856,8 @@ fn main() {
 }
 
 #[test]
-fn manual_is_empty_greater_than_zero() {
-    assert_lint_snapshot!(
+fn manual_is_empty_greater_than_zero_no_warning() {
+    assert_no_lint_warnings!(
         r#"
 fn main() {
   let xs = [1, 2, 3]
@@ -931,6 +931,30 @@ fn main() {
     );
 }
 
+#[test]
+fn manual_is_empty_zero_less_than_no_warning() {
+    assert_no_lint_warnings!(
+        r#"
+fn main() {
+  let xs = [1, 2, 3]
+  let _ = 0 < xs.length()
+}
+"#
+    );
+}
+
+#[test]
+fn manual_is_empty_zero_not_equals_no_warning() {
+    assert_no_lint_warnings!(
+        r#"
+fn main() {
+  let xs = [1, 2, 3]
+  let _ = 0 != xs.length()
+}
+"#
+    );
+}
+
 #[test]
 fn manual_is_empty_compare_one_no_warning() {
     assert_no_lint_warnings!(
diff --git a/tests/ui/lint/snapshots/manual_is_empty_greater_than_zero.snap b/tests/ui/lint/snapshots/manual_is_empty_greater_than_zero.snap
deleted file mode 100644
index b54aeef1b..000000000
--- a/tests/ui/lint/snapshots/manual_is_empty_greater_than_zero.snap
+++ /dev/null
@@ -1,12 +0,0 @@
----
-source: tests/ui/lint/mod.rs
----
-  [info] Length comparison can use `is_empty()`
-   ╭─[test.lis:4:11]
- 3 │   let xs = [1, 2, 3]
- 4 │   let _ = xs.length() > 0
-   ·           ───────┬───────
-   ·                  ╰── can be simpler
- 5 │ }
-   ╰────
-  help: Simplify to `!xs.is_empty()` · code: [lint.manual_is_empty]
diff --git a/tests/ui/lint/snapshots/manual_is_empty_not_equals_zero.snap b/tests/ui/lint/snapshots/manual_is_empty_not_equals_zero.snap
deleted file mode 100644
index 2fdf2766f..000000000
--- a/tests/ui/lint/snapshots/manual_is_empty_not_equals_zero.snap
+++ /dev/null
@@ -1,12 +0,0 @@
----
-source: tests/ui/lint/mod.rs
----
-  [info] Length comparison can use `is_empty()`
-   ╭─[test.lis:4:11]
- 3 │   let xs = [1, 2, 3]
- 4 │   let _ = xs.length() != 0
-   ·           ────────┬───────
-   ·                   ╰── can be simpler
- 5 │ }
-   ╰────
-  help: Simplify to `!xs.is_empty()` · code: [lint.manual_is_empty]