diff --git a/engine/src/flutter/common/config.gni b/engine/src/flutter/common/config.gni
index a9274612223..a3eb20b19a5 100644
--- a/engine/src/flutter/common/config.gni
+++ b/engine/src/flutter/common/config.gni
@@ -68,11 +68,3 @@ if (is_fuchsia) {
 if ((is_ios || is_mac) && defined(enable_bitcode)) {
   flutter_enable_bitcode = enable_bitcode
 }
-
-if (is_ios || is_mac) {
-  flutter_cflags_objc = [
-    "-Werror=overriding-method-mismatch",
-    "-Werror=undeclared-selector",
-  ]
-  flutter_cflags_objcc = flutter_cflags_objc
-}
diff --git a/engine/src/flutter/fml/BUILD.gn b/engine/src/flutter/fml/BUILD.gn
index f72ac64bc6a..9b5626e787b 100644
--- a/engine/src/flutter/fml/BUILD.gn
+++ b/engine/src/flutter/fml/BUILD.gn
@@ -120,9 +120,6 @@ source_set("fml") {
   }
 
   if (is_ios || is_mac) {
-    cflags_objc = flutter_cflags_objc
-    cflags_objcc = flutter_cflags_objcc
-
     sources += [
       "platform/darwin/cf_utils.cc",
       "platform/darwin/cf_utils.h",
diff --git a/engine/src/flutter/shell/platform/darwin/BUILD.gn b/engine/src/flutter/shell/platform/darwin/BUILD.gn
index bfc29dfe79d..f5271ca366e 100644
--- a/engine/src/flutter/shell/platform/darwin/BUILD.gn
+++ b/engine/src/flutter/shell/platform/darwin/BUILD.gn
@@ -20,9 +20,6 @@ group("darwin") {
 }
 
 source_set("flutter_channels") {
-  cflags_objc = flutter_cflags_objc
-  cflags_objcc = flutter_cflags_objcc
-
   sources = [
     "common/buffer_conversions.h",
     "common/buffer_conversions.mm",
diff --git a/engine/src/flutter/shell/platform/darwin/common/BUILD.gn b/engine/src/flutter/shell/platform/darwin/common/BUILD.gn
index 45a9e3092b2..8c5663e84c4 100644
--- a/engine/src/flutter/shell/platform/darwin/common/BUILD.gn
+++ b/engine/src/flutter/shell/platform/darwin/common/BUILD.gn
@@ -2,13 +2,9 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//flutter/common/config.gni")
 import("framework_shared.gni")
 
 source_set("common") {
-  cflags_objc = flutter_cflags_objc
-  cflags_objcc = flutter_cflags_objcc
-
   sources = [
     "buffer_conversions.h",
     "buffer_conversions.mm",
@@ -38,9 +34,6 @@ config("framework_relative_headers") {
 
 # Framework code shared between iOS and macOS.
 source_set("framework_shared") {
-  cflags_objc = flutter_cflags_objc
-  cflags_objcc = flutter_cflags_objcc
-
   sources = [
     "framework/Source/FlutterChannels.mm",
     "framework/Source/FlutterCodecs.mm",
diff --git a/engine/src/flutter/shell/platform/darwin/common/framework/Source/FlutterCodecs.mm b/engine/src/flutter/shell/platform/darwin/common/framework/Source/FlutterCodecs.mm
index 6e9b60cbd73..b06dab7b855 100644
--- a/engine/src/flutter/shell/platform/darwin/common/framework/Source/FlutterCodecs.mm
+++ b/engine/src/flutter/shell/platform/darwin/common/framework/Source/FlutterCodecs.mm
@@ -13,8 +13,7 @@
   return _sharedInstance;
 }
 
-- (NSData*)encode:(id)message {
-  NSAssert([message isKindOfClass:[NSData class]], @"");
+- (NSData*)encode:(NSData*)message {
   return message;
 }
 
@@ -32,12 +31,10 @@
   return _sharedInstance;
 }
 
-- (NSData*)encode:(id)message {
-  NSAssert([message isKindOfClass:[NSString class]], @"");
-  NSString* stringMessage = message;
+- (NSData*)encode:(NSString*)message {
   if (message == nil)
     return nil;
-  const char* utf8 = stringMessage.UTF8String;
+  const char* utf8 = message.UTF8String;
   return [NSData dataWithBytes:utf8 length:strlen(utf8)];
 }
 
diff --git a/engine/src/flutter/shell/platform/darwin/ios/BUILD.gn b/engine/src/flutter/shell/platform/darwin/ios/BUILD.gn
index d9be6e2a9f1..c98e2b31bf3 100644
--- a/engine/src/flutter/shell/platform/darwin/ios/BUILD.gn
+++ b/engine/src/flutter/shell/platform/darwin/ios/BUILD.gn
@@ -46,9 +46,6 @@ shared_library("create_flutter_framework_dylib") {
 
   public = _flutter_framework_headers
 
-  cflags_objc = flutter_cflags_objc
-  cflags_objcc = flutter_cflags_objcc
-
   sources = [
     "framework/Source/FlutterAppDelegate.mm",
     "framework/Source/FlutterBinaryMessengerRelay.mm",
diff --git a/engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterAppDelegate.mm b/engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterAppDelegate.mm
index 3a6d113b5e4..204261cf2b1 100644
--- a/engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterAppDelegate.mm
+++ b/engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterAppDelegate.mm
@@ -8,6 +8,8 @@
 #include "flutter/shell/platform/darwin/ios/framework/Headers/FlutterViewController.h"
 #include "flutter/shell/platform/darwin/ios/framework/Source/FlutterPluginAppLifeCycleDelegate_internal.h"
 
+#pragma GCC diagnostic error "-Woverriding-method-mismatch"
+
 static NSString* kUIBackgroundMode = @"UIBackgroundModes";
 static NSString* kRemoteNotificationCapabitiliy = @"remote-notification";
 static NSString* kBackgroundFetchCapatibility = @"fetch";