shader compile error on Xcode 13

Hi
I'm trying to show .glb file on swift.
I read the sample file and attached it on my Xcode project with same Assets.
But I encountered error like this.
Any help??

[SceneKit] Error: FATAL ERROR : failed compiling shader: Error Domain=MTLLibraryErrorDomain Code=3 "program_source:3718:1: error: C++ requires a type specifier for all declarations , constant float& metallicFactor ^ " UserInfo={NSLocalizedDescription=program_source:3718:1: error: C++ requires a type specifier for all declarations , constant float& metallicFactor ^ }