Addressed review comments

Removed the silencing for incompatible-pointer-types
Removed unused objects
Fixed format issues

src/objective-c/ProtoRPC/ProtoService.m

@@ -65,13 +65,11 @@
   return self;
 }
 
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wincompatible-pointer-types"
 - (ProtoRPC *)RPCToMethod:(NSString *)method
            requestsWriter:(GRXWriter *)requestsWriter
             responseClass:(Class)responseClass
        responsesWriteable:(id<GRXWriteable>)responsesWriteable {
-  ProtoMethod *methodName = [[ProtoMethod alloc] initWithPackage:_packageName
+  GRPCProtoMethod *methodName = [[GRPCProtoMethod alloc] initWithPackage:_packageName
                                                                  service:_serviceName
                                                                   method:method];
   return [[ProtoRPC alloc] initWithHost:_host
@@ -80,7 +78,6 @@
                           responseClass:responseClass
                      responsesWriteable:responsesWriteable];
 }
-#pragma clang diagnostic pop
 @end
 
 @implementation GRPCProtoService

src/objective-c/tests/GRPCClientTests.m

@@ -303,7 +303,7 @@ static GRPCProtoMethod *kUnaryCallMethod;
 
   // Try to set parameters to nil for GRPCCall. This should cause an exception
   @try {
-    GRPCCall *call __unused = [[GRPCCall alloc] initWithHost:nil
+    (void)[[GRPCCall alloc] initWithHost:nil
                                     path:nil
                           requestsWriter:nil];
     XCTFail(@"Did not receive an exception when parameters are nil");
@@ -316,7 +316,7 @@ static GRPCProtoMethod *kUnaryCallMethod;
   GRXWriter *requestsWriter = [GRXWriter emptyWriter];
   [requestsWriter finishWithError:nil];
   @try {
-    GRPCCall *call __unused = [[GRPCCall alloc] initWithHost:kHostAddress
+    (void)[[GRPCCall alloc] initWithHost:kHostAddress
                                     path:kUnaryCallMethod.HTTPPath
                           requestsWriter:requestsWriter];
     XCTFail(@"Did not receive an exception when GRXWriter has incorrect state.");

src/objective-c/tests/Podfile

@@ -6,7 +6,7 @@ install! 'cocoapods', :deterministic_uuids => false
 def shared_pods
   pod 'Protobuf', :path => "../../../third_party/protobuf", :inhibit_warnings => true
   pod 'BoringSSL', :podspec => "..", :inhibit_warnings => true
-  pod 'CronetFramework', :podspec => "..", :inhibit_warnings => true
+  pod 'CronetFramework', :podspec => ".."
   pod 'gRPC', :path => "../../.."
   pod 'RemoteTest', :path => "RemoteTestClient"
 end
@@ -42,6 +42,7 @@ post_install do |installer|
     end
     if target.name == 'gRPC'
       target.build_configurations.each do |config|
+        # TODO(zyc) Remove this setting after the issue is resolved
         # GPR_UNREACHABLE_CODE causes "Control may reach end of non-void
         # function" warning
         config.build_settings['GCC_WARN_ABOUT_RETURN_TYPE'] = 'NO'