[ruff] skip fix for RUF059 if dummy name is already bound (unused-unpacked-variable) (#18509)

Author: chirizxc

crates/ruff_linter/resources/test/fixtures/ruff/RUF059_0.py

@@ -94,3 +94,9 @@ def f():
         (exponential := (exponential * base_multiplier) % 3): i + 1 for i in range(2)
     }
     return hash_map
+
+
+# see: https://github.com/astral-sh/ruff/issues/18507
+def f(_x):
+    x, = "1"
+    print(_x)

crates/ruff_linter/src/rules/ruff/rules/unused_unpacked_variable.rs

@@ -3,6 +3,7 @@ use ruff_python_semantic::Binding;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
+use crate::renamer::ShadowedKind;
 use crate::{Edit, Fix, FixAvailability, Violation};
 
 /// ## What it does
@@ -63,6 +64,11 @@ fn remove_unused_variable(binding: &Binding, checker: &Checker) -> Option<Fix> {
 
     let name = binding.name(checker.source());
     let renamed = format!("_{name}");
+
+    if ShadowedKind::new(binding, &renamed, checker).shadows_any() {
+        return None;
+    }
+
     if checker.settings.dummy_variable_rgx.is_match(&renamed) {
         let edit = Edit::range_replacement(renamed, binding.range());
 

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF059_RUF059_0.py.snap

@@ -197,4 +197,14 @@ RUF059_0.py:86:29: RUF059 [*] Unpacked variable `that` is never used
    86 |+        open("") as ((this, _that)),
 87 87 |     ):
 88 88 |         print("hello")
-89 89 |
+89 89 | 
+
+RUF059_0.py:101:5: RUF059 Unpacked variable `x` is never used
+    |
+ 99 | # see: https://github.com/astral-sh/ruff/issues/18507
+100 | def f(_x):
+101 |     x, = "1"
+    |     ^ RUF059
+102 |     print(_x)
+    |
+    = help: Prefix it with an underscore or any other dummy variable pattern