Add a new Binding::is_unused method (#12729)

crates/ruff_python_semantic/src/binding.rs

@@ -36,9 +36,18 @@ pub struct Binding<'a> {
 }
 
 impl<'a> Binding<'a> {
+    /// Return `true` if this [`Binding`] is unused.
+    ///
+    /// This method is the opposite of [`Binding::is_used`].
+    pub fn is_unused(&self) -> bool {
+        self.references.is_empty()
+    }
+
     /// Return `true` if this [`Binding`] is used.
+    ///
+    /// This method is the opposite of [`Binding::is_unused`].
     pub fn is_used(&self) -> bool {
-        !self.references.is_empty()
+        !self.is_unused()
     }
 
     /// Returns an iterator over all references for the current [`Binding`].

crates/ruff_python_semantic/src/model.rs

@@ -1455,7 +1455,7 @@ impl<'a> SemanticModel<'a> {
                     .get_all(id)
                     .map(|binding_id| self.binding(binding_id))
                     .filter(|binding| binding.start() >= expr.start())
-                    .all(|binding| !binding.is_used())
+                    .all(Binding::is_unused)
             }
             _ => false,
         }