Avoid removing too many imports in redefined-while-unused

crates/ruff_linter/resources/test/fixtures/pyflakes/F811_32.py

@@ -0,0 +1,9 @@
+"""Regression test for: https://github.com/astral-sh/ruff/issues/15583"""
+
+from typing import (
+    List,
+    List,
+)
+
+
+def foo() -> List[int]: ...

crates/ruff_linter/src/fix/codemods.rs

@@ -7,7 +7,7 @@ use libcst_native::{
     Codegen, CodegenState, Expression, ImportNames, NameOrAttribute, ParenthesizableWhitespace,
     SmallStatement, Statement,
 };
-use rustc_hash::FxHashSet;
+use rustc_hash::{FxHashMap, FxHashSet};
 use smallvec::{smallvec, SmallVec};
 use unicode_normalization::UnicodeNormalization;
 
@@ -81,10 +81,20 @@ pub(crate) fn remove_imports<'a>(
     // Preserve the trailing comma (or not) from the last entry.
     let trailing_comma = aliases.last().and_then(|alias| alias.comma.clone());
 
-    // Remove any imports that are specified in the `imports` iterator.
-    let member_names = member_names.collect::<FxHashSet<_>>();
+    // Remove any imports that are specified in the `imports` iterator (but, e.g., if the name is
+    // provided once, only remove the first occurrence).
+    let mut counts = member_names.fold(FxHashMap::<&str, usize>::default(), |mut map, name| {
+        map.entry(name).and_modify(|c| *c += 1).or_insert(1);
+        map
+    });
     aliases.retain(|alias| {
-        !member_names.contains(qualified_name_from_name_or_attribute(&alias.name).as_str())
+        let name = qualified_name_from_name_or_attribute(&alias.name);
+        if let Some(count) = counts.get_mut(name.as_str()).filter(|count| **count > 0) {
+            *count -= 1;
+            false
+        } else {
+            true
+        }
     });
 
     // But avoid destroying any trailing comments.

crates/ruff_linter/src/rules/pyflakes/mod.rs

@@ -129,6 +129,7 @@ mod tests {
     #[test_case(Rule::RedefinedWhileUnused, Path::new("F811_29.pyi"))]
     #[test_case(Rule::RedefinedWhileUnused, Path::new("F811_30.py"))]
     #[test_case(Rule::RedefinedWhileUnused, Path::new("F811_31.py"))]
+    #[test_case(Rule::RedefinedWhileUnused, Path::new("F811_32.py"))]
     #[test_case(Rule::UndefinedName, Path::new("F821_0.py"))]
     #[test_case(Rule::UndefinedName, Path::new("F821_1.py"))]
     #[test_case(Rule::UndefinedName, Path::new("F821_2.py"))]

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F811_F811_32.py.snap

@@ -0,0 +1,21 @@
+---
+source: crates/ruff_linter/src/rules/pyflakes/mod.rs
+---
+F811_32.py:5:5: F811 [*] Redefinition of unused `List` from line 4
+  |
+3 | from typing import (
+4 |     List,
+5 |     List,
+  |     ^^^^ F811
+6 | )
+  |
+  = help: Remove definition: `List`
+
+ℹ Safe fix
+2 2 | 
+3 3 | from typing import (
+4 4 |     List,
+5   |-    List,
+6 5 | )
+7 6 | 
+8 7 |