fix(es/helpers): Fix syntax context of helpers (#4900)

crates/swc/tests/fixture/issues-4xxx/4891/input/.swcrc

@@ -0,0 +1,18 @@
+{
+    "jsc": {
+        "parser": {
+            "syntax": "typescript",
+            "tsx": false
+        },
+        "target": "es2017",
+        "loose": true,
+        "minify": {
+            "compress": false,
+            "mangle": false
+        }
+    },
+    "module": {
+        "type": "es6"
+    },
+    "minify": false
+}

crates/swc/tests/fixture/issues-4xxx/4891/input/index.ts

@@ -0,0 +1,12 @@
+export class LocalStorageChannel {
+    readonly #channelName: string;
+    #listeners: MessageListener[];
+
+    constructor(channelName: string) {
+        this.#channelName = channelName;
+        this.#listeners = [];
+        window.addEventListener("storage", (event) =>
+            this.onStorageEvent(event)
+        );
+    }
+}

crates/swc/tests/fixture/issues-4xxx/4891/output/index.ts

@@ -0,0 +1,18 @@
+import _class_private_field_loose_base from "@swc/helpers/lib/_class_private_field_loose_base.js";
+import _class_private_field_loose_key from "@swc/helpers/lib/_class_private_field_loose_key.js";
+var _channelName = _class_private_field_loose_key("_channelName"), _listeners = _class_private_field_loose_key("_listeners");
+export class LocalStorageChannel {
+    constructor(channelName){
+        Object.defineProperty(this, _channelName, {
+            writable: true,
+            value: void 0
+        });
+        Object.defineProperty(this, _listeners, {
+            writable: true,
+            value: void 0
+        });
+        _class_private_field_loose_base(this, _channelName)[_channelName] = channelName;
+        _class_private_field_loose_base(this, _listeners)[_listeners] = [];
+        window.addEventListener("storage", (event)=>this.onStorageEvent(event));
+    }
+}

crates/swc_ecma_transforms_base/src/helpers/mod.rs

@@ -479,7 +479,13 @@ impl VisitMut for Marker {
     }
 
     fn visit_mut_var_declarator(&mut self, v: &mut VarDeclarator) {
-        if let Pat::Ident(i) = &v.name {
+        if let Pat::Ident(i) = &mut v.name {
+            if &*i.id.sym == "id" {
+                i.id.span.ctxt = self.base;
+                self.decls.insert(i.id.sym.clone(), self.base);
+                return;
+            }
+
             if &*i.id.sym != "_typeof" && !i.id.sym.starts_with("__") {
                 self.decls.insert(i.id.sym.clone(), self.decl_ctxt);
             }