错误提示如下：

duplicate symbol _OBJC_IVAR_$_MaterialListDetailViewController._collectionView in:

    /Users/jxc/Library/Developer/Xcode/DerivedData/zhxf-bxzgtcvzvswvytglvejaqcgqxhmb/Build/Intermediates/zhxf.build/Debug-iphoneos/zhba.build/Objects-normal/arm64/MaterialClaimListViewController.o

    /Users/jxc/Library/Developer/Xcode/DerivedData/zhxf-bxzgtcvzvswvytglvejaqcgqxhmb/Build/Intermediates/zhxf.build/Debug-iphoneos/zhba.build/Objects-normal/arm64/MaterialListDetailViewController.o

duplicate symbol _OBJC_IVAR_$_MaterialListDetailViewController._materials in:

    /Users/jxc/Library/Developer/Xcode/DerivedData/zhxf-bxzgtcvzvswvytglvejaqcgqxhmb/Build/Intermediates/zhxf.build/Debug-iphoneos/zhba.build/Objects-normal/arm64/MaterialClaimListViewController.o

    /Users/jxc/Library/Developer/Xcode/DerivedData/zhxf-bxzgtcvzvswvytglvejaqcgqxhmb/Build/Intermediates/zhxf.build/Debug-iphoneos/zhba.build/Objects-normal/arm64/MaterialListDetailViewController.o

duplicate symbol _OBJC_CLASS_$_MaterialListDetailViewController in:

    /Users/jxc/Library/Developer/Xcode/DerivedData/zhxf-bxzgtcvzvswvytglvejaqcgqxhmb/Build/Intermediates/zhxf.build/Debug-iphoneos/zhba.build/Objects-normal/arm64/MaterialClaimListViewController.o

    /Users/jxc/Library/Developer/Xcode/DerivedData/zhxf-bxzgtcvzvswvytglvejaqcgqxhmb/Build/Intermediates/zhxf.build/Debug-iphoneos/zhba.build/Objects-normal/arm64/MaterialListDetailViewController.o

duplicate symbol _OBJC_METACLASS_$_MaterialListDetailViewController in:

    /Users/jxc/Library/Developer/Xcode/DerivedData/zhxf-bxzgtcvzvswvytglvejaqcgqxhmb/Build/Intermediates/zhxf.build/Debug-iphoneos/zhba.build/Objects-normal/arm64/MaterialClaimListViewController.o

    /Users/jxc/Library/Developer/Xcode/DerivedData/zhxf-bxzgtcvzvswvytglvejaqcgqxhmb/Build/Intermediates/zhxf.build/Debug-iphoneos/zhba.build/Objects-normal/arm64/MaterialListDetailViewController.o

ld: 4 duplicate symbols for architecture arm64

clang: error: linker command failed with exit code 1 (use -v to see invocation)

仔细思考，项目内搜索并没有重复定义的问题，然后发现在MaterialClaimListViewController.m 里面倒入了MaterialListDetailViewController.m文件

所以出现类似情况，有可能是你不小心导入了 .m文件