Issues #92, #148: simplified to use expr.accept(visitor)

Author: tozpeak

lib/src/common/visitors/select_expression_identifiers_visitor.dart

@@ -13,14 +13,4 @@ class SelectExpressionIdentifiersVisitor extends RecursiveAstVisitor<void> {
     super.visitSimpleIdentifier(node);
     _identifiers.add(node);
   }
-
-  /// Helper method to process expression, even if it is a SimpleIdentifier
-  void selectFromExpression(Expression expr) {
-    if (expr case final SimpleIdentifier identifier) {
-      _identifiers.add(identifier);
-      return;
-    }
-
-    expr.visitChildren(this);
-  }
 }

lib/src/lints/avoid_unnecessary_return_variable/avoid_unnecessary_return_variable_rule.dart

@@ -118,7 +118,7 @@ Rewrite the variable evaluation into return statement instead.""",
 
   bool _isExpressionImmutable(Expression expr) {
     final visitor = SelectExpressionIdentifiersVisitor();
-    visitor.selectFromExpression(expr);
+    expr.accept(visitor);
 
     return visitor.identifiers.every(_isSimpleIdentifierImmutable);
   }