Fix builds.

src/api/run.rs

@@ -26,11 +26,7 @@ impl Engine {
             self.lex_raw(&scripts, self.token_mapper.as_ref().map(Box::as_ref));
         let mut state = ParseState::new(self, scope, tokenizer_control);
 
-        let ast = self.parse(
-            &mut stream.peekable(),
-            &mut state,
-            self.optimization_level(),
-        )?;
+        let ast = self.parse(&mut stream.peekable(), &mut state, self.optimization_level)?;
 
         self.run_ast_with_scope(scope, &ast)
     }