fix: capture destructured function parameters

crates/oxide_emit/src/closure.rs

@@ -15,21 +15,19 @@ impl Emitter {
     fn collect_fn_param_names(&self, params: &oxide_parser::FormalParameters) -> HashSet<String> {
         let mut names = HashSet::new();
         for p in &params.items {
-            if let oxide_parser::BindingPattern::BindingIdentifier(bi) = &p.pattern {
-                names.insert(bi.name.to_string());
-            }
+            self.collect_binding_pattern_names(&p.pattern, &mut names);
         }
         // rest 形参也是本函数作用域绑定，遮蔽外层同名变量。
         if let Some(rest) = &params.rest {
-            if let oxide_parser::BindingPattern::BindingIdentifier(bi) = &rest.rest.argument {
-                names.insert(bi.name.to_string());
-            }
+            self.collect_binding_pattern_names(&rest.rest.argument, &mut names);
         }
         names
     }
 
     /// 递归收集 binding pattern 内全部绑定标识符名（解构 `[a, b]` / `{x: y}` 嵌套）。
-    fn collect_binding_pattern_names(&self, pattern: &oxide_parser::BindingPattern, out: &mut HashSet<String>) {
+    pub(crate) fn collect_binding_pattern_names(
+        &self, pattern: &oxide_parser::BindingPattern, out: &mut HashSet<String>,
+    ) {
         match pattern {
             oxide_parser::BindingPattern::BindingIdentifier(bi) => {
                 out.insert(bi.name.to_string());

crates/oxide_emit/src/emit.rs

@@ -1100,6 +1100,11 @@ impl Emitter {
             }
         }
         ctx.own_bindings = self.collect_own_binding_names(&param_names, body_stmts);
+        for spec in param_specs {
+            if let ParamSpec::Pattern { pattern, .. } = spec {
+                self.collect_binding_pattern_names(pattern, &mut ctx.own_bindings);
+            }
+        }
 
         // 自动声明 arguments 绑定（非箭头函数，且用户未显式声明同名标识符）。
         // 先登记符号并纳入 own_bindings，使嵌套箭头引用 arguments 被识别为本函数

crates/oxide_vm/tests/destructuring_tests.rs

@@ -88,6 +88,17 @@ fn function_and_method_parameter_destructuring() {
     assert_num(result, 10.0);
 }
 
+#[test]
+fn destructured_callback_parameters_shadow_outer_bindings() {
+    let mut vm = Vm::new();
+    let result = eval(
+        &mut vm,
+        "let expected=100, result=0; [[1,2]].forEach(([value, expected]) => { result=value+expected; }); result",
+    )
+    .unwrap();
+    assert_num(result, 3.0);
+}
+
 // 回归：赋值目标含嵌套 rest 模式（rest 元素本身是模式，如 `[...[x]]`）的 for-of
 // 曾无限循环 / 报错，因为计数器相对 emitter 少计了 rest 目标的指令，破坏了循环跳转
 // 偏移。（对象 rest 嵌套目标按规范是语法错误，故不测。）