Unused parameters naming.

src/optimizer.rs

@@ -863,7 +863,7 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
 }
 
 /// Optimize an [expression][Expr].
-fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, chaining: bool) {
+fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, _chaining: bool) {
     // These keywords are handled specially
     const DONT_EVAL_KEYWORDS: &[&str] = &[
         KEYWORD_PRINT, // side effects
@@ -871,8 +871,6 @@ fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, chaining: bool) {
         KEYWORD_EVAL,  // arbitrary scripts
     ];
 
-    let _chaining = chaining;
-
     match expr {
         // {}
         Expr::Stmt(x) if x.is_empty() => { state.set_dirty(); *expr = Expr::Unit(x.position()) }