[flake8-comprehensions] Do not emit unnecessary-map diagnostic when lambda has different arity (C417)

[InSyncWithFoo]

Summary

Resolves #15796.

The cases discussed in the aforementioned issue are no longer reported.

Test Plan

cargo nextest run and cargo insta test.

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

[AlexWaygood]

You can do this to fix the Clippy error:

diff --git a/crates/ruff_linter/src/rules/flake8_comprehensions/rules/unnecessary_map.rs b/crates/ruff_linter/src/rules/flake8_comprehensions/rules/unnecessary_map.rs
index 2b21e1806..8cb0a08f3 100644
--- a/crates/ruff_linter/src/rules/flake8_comprehensions/rules/unnecessary_map.rs
+++ b/crates/ruff_linter/src/rules/flake8_comprehensions/rules/unnecessary_map.rs
@@ -111,7 +111,7 @@ pub(crate) fn unnecessary_map(
                 return;
             }
 
-            if !lambda_has_expected_arity(parameters.as_ref(), body) {
+            if !lambda_has_expected_arity(parameters.as_deref(), body) {
                 return;
             }
         }
@@ -146,7 +146,7 @@ pub(crate) fn unnecessary_map(
                 return;
             };
 
-            if !lambda_has_expected_arity(parameters.as_ref(), body) {
+            if !lambda_has_expected_arity(parameters.as_deref(), body) {
                 return;
             }
         }
@@ -191,7 +191,7 @@ pub(crate) fn unnecessary_map(
                 return;
             }
 
-            if !lambda_has_expected_arity(parameters.as_ref(), body) {
+            if !lambda_has_expected_arity(parameters.as_deref(), body) {
                 return;
             }
         }
@@ -216,11 +216,10 @@ pub(crate) fn unnecessary_map(
 /// * It has exactly one parameter
 /// * That parameter is not variadic
 /// * That parameter does not have a default value
-fn lambda_has_expected_arity(parameters: Option<&Box<Parameters>>, body: &Expr) -> bool {
+fn lambda_has_expected_arity(parameters: Option<&Parameters>, body: &Expr) -> bool {
     let Some(parameters) = parameters else {
         return false;
     };
-    let parameters = parameters.as_ref();
 
     let [parameter] = &parameters.args[..] else {
         return false;

[AlexWaygood]

Thanks!