diff --git a/pkg/compiler/test/analyses/api_allowed.json b/pkg/compiler/test/analyses/api_allowed.json
index 34db6851a65..500928cb372 100644
--- a/pkg/compiler/test/analyses/api_allowed.json
+++ b/pkg/compiler/test/analyses/api_allowed.json
@@ -52,7 +52,6 @@
     "Dynamic invocation of '[]'.": 7
   },
   "org-dartlang-sdk:///lib/io/io_resource_info.dart": {
-    "Dynamic invocation of '[]'.": 1,
     "Dynamic access of 'path'.": 1,
     "Dynamic access of 'dart.io::_path'.": 1,
     "Dynamic access of 'pid'.": 1,
diff --git a/sdk/lib/io/io_resource_info.dart b/sdk/lib/io/io_resource_info.dart
index 3ba76c965ae..0954a559416 100644
--- a/sdk/lib/io/io_resource_info.dart
+++ b/sdk/lib/io/io_resource_info.dart
@@ -112,7 +112,8 @@ class _FileResourceInfo extends _ReadWriteResourceInfo {
     ));
   }
 
-  static Future<ServiceExtensionResponse> getOpenFiles(function, params) {
+  static Future<ServiceExtensionResponse> getOpenFiles(
+      String function, Map<String, String> params) {
     assert(function == 'ext.dart.io.getOpenFiles');
     final data = {
       'type': 'OpenFileList',
@@ -125,7 +126,7 @@ class _FileResourceInfo extends _ReadWriteResourceInfo {
   Map<String, dynamic> get fileInfoMap => fullValueMap;
 
   static Future<ServiceExtensionResponse> getOpenFileInfoMapByID(
-      function, params) {
+      String function, Map<String, String> params) {
     final id = int.parse(params['id']!);
     final result = openFiles.containsKey(id) ? openFiles[id]!.fileInfoMap : {};
     final jsonValue = json.encode(result);