[ruff] Check for shadowed map before suggesting fix (RUF058) (#15790)

## Summary

Fixes #15786 by not suggesting a fix if `map` doesn't have its builtin
binding.

## Test Plan

New test taken from the report in #15786.

crates/ruff_linter/resources/test/fixtures/ruff/RUF058_1.py

@@ -0,0 +1,11 @@
+"""Regression test for https://github.com/astral-sh/ruff/issues/15786. This
+should be separate from other tests because it shadows the `map` builtin.
+
+This should still get a diagnostic but not a fix that would lead to an error.
+"""
+
+from itertools import starmap
+
+map = {}
+for _ in starmap(print, zip("A", "12")):
+    pass

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

@@ -426,7 +426,8 @@ mod tests {
     #[test_case(Rule::PytestRaisesAmbiguousPattern, Path::new("RUF043.py"))]
     #[test_case(Rule::UnnecessaryRound, Path::new("RUF057.py"))]
     #[test_case(Rule::DataclassEnum, Path::new("RUF049.py"))]
-    #[test_case(Rule::StarmapZip, Path::new("RUF058.py"))]
+    #[test_case(Rule::StarmapZip, Path::new("RUF058_0.py"))]
+    #[test_case(Rule::StarmapZip, Path::new("RUF058_1.py"))]
     fn preview_rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!(
             "preview__{}_{}",

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

@@ -1,5 +1,5 @@
 use crate::checkers::ast::Checker;
-use ruff_diagnostics::{AlwaysFixableViolation, Applicability, Diagnostic, Edit, Fix};
+use ruff_diagnostics::{Applicability, Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, ViolationMetadata};
 use ruff_python_ast::{parenthesize::parenthesized_range, Expr, ExprCall};
 use ruff_python_parser::TokenKind;
@@ -28,17 +28,29 @@ use ruff_text_size::{Ranged, TextRange};
 /// map(func, a, b)
 /// map(func, a, b, strict=True)  # 3.14+
 /// ```
+///
+/// ## Fix safety
+///
+/// This rule's fix is marked as unsafe if the `starmap` or `zip` expressions contain comments that
+/// would be deleted by applying the fix. Otherwise, the fix can be applied safely.
+///
+/// ## Fix availability
+///
+/// This rule will emit a diagnostic but not suggest a fix if `map` has been shadowed from its
+/// builtin binding.
 #[derive(ViolationMetadata)]
 pub(crate) struct StarmapZip;
 
-impl AlwaysFixableViolation for StarmapZip {
+impl Violation for StarmapZip {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
     #[derive_message_formats]
     fn message(&self) -> String {
         "`itertools.starmap` called on `zip` iterable".to_string()
     }
 
-    fn fix_title(&self) -> String {
-        "Use `map` instead".to_string()
+    fn fix_title(&self) -> Option<String> {
+        Some("Use `map` instead".to_string())
     }
 }
 
@@ -77,13 +89,21 @@ pub(crate) fn starmap_zip(checker: &mut Checker, call: &ExprCall) {
         return;
     }
 
-    let fix = replace_with_map(call, iterable_call, checker);
-    let diagnostic = Diagnostic::new(StarmapZip, call.range);
+    let mut diagnostic = Diagnostic::new(StarmapZip, call.range);
 
-    checker.diagnostics.push(diagnostic.with_fix(fix));
+    if let Some(fix) = replace_with_map(call, iterable_call, checker) {
+        diagnostic.set_fix(fix);
+    }
+
+    checker.diagnostics.push(diagnostic);
 }
 
-fn replace_with_map(starmap: &ExprCall, zip: &ExprCall, checker: &Checker) -> Fix {
+/// Replace the `starmap` call with a call to the `map` builtin, if `map` has not been shadowed.
+fn replace_with_map(starmap: &ExprCall, zip: &ExprCall, checker: &Checker) -> Option<Fix> {
+    if !checker.semantic().has_builtin_binding("map") {
+        return None;
+    }
+
     let change_func_to_map = Edit::range_replacement("map".to_string(), starmap.func.range());
 
     let mut remove_zip = vec![];
@@ -149,5 +169,9 @@ fn replace_with_map(starmap: &ExprCall, zip: &ExprCall, checker: &Checker) -> Fi
         Applicability::Safe
     };
 
-    Fix::applicable_edits(change_func_to_map, remove_zip, applicability)
+    Some(Fix::applicable_edits(
+        change_func_to_map,
+        remove_zip,
+        applicability,
+    ))
 }

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__preview__RUF058_RUF058_0.py.snap

@@ -1,7 +1,7 @@
 ---
 source: crates/ruff_linter/src/rules/ruff/mod.rs
 ---
-RUF058.py:7:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
+RUF058_0.py:7:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
   |
 5 | # Errors
 6 |
@@ -21,7 +21,7 @@ RUF058.py:7:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
 9 9 | 
 10 10 | 
 
-RUF058.py:8:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
+RUF058_0.py:8:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
   |
 7 | starmap(func, zip())
 8 | starmap(func, zip([]))
@@ -39,7 +39,7 @@ RUF058.py:8:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
 10 10 | 
 11 11 | starmap(func, zip(a, b, c,),)
 
-RUF058.py:11:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
+RUF058_0.py:11:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
    |
 11 | starmap(func, zip(a, b, c,),)
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF058
@@ -56,7 +56,7 @@ RUF058.py:11:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
 13 13 | 
 14 14 | starmap(
 
-RUF058.py:14:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
+RUF058_0.py:14:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
    |
 14 | / starmap(
 15 | |     func,  # Foo
@@ -88,7 +88,7 @@ RUF058.py:14:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
 21 21 | 
 22 22 | (  # Foo
 
-RUF058.py:22:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
+RUF058_0.py:22:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
    |
 20 |   )
 21 |
@@ -124,7 +124,7 @@ RUF058.py:22:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
 30 28 | 
 31 29 | (  # Foobar
 
-RUF058.py:31:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
+RUF058_0.py:31:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
    |
 29 |   )
 30 |
@@ -182,7 +182,7 @@ RUF058.py:31:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
 50 42 | 
 51 43 | starmap(
 
-RUF058.py:51:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
+RUF058_0.py:51:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
    |
 49 |   )
 50 |

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__preview__RUF058_RUF058_1.py.snap

@@ -0,0 +1,11 @@
+---
+source: crates/ruff_linter/src/rules/ruff/mod.rs
+---
+RUF058_1.py:10:10: RUF058 `itertools.starmap` called on `zip` iterable
+   |
+ 9 | map = {}
+10 | for _ in starmap(print, zip("A", "12")):
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF058
+11 |     pass
+   |
+   = help: Use `map` instead