錯誤提示如下：
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)
仔細思考，項目內搜索並沒有重複定義的問題，然後發現在MaterialClaimListViewController.m 裏面倒入了MaterialListDetailViewController.m文件
所以出現類似情況，有可能是你不小心導入了 .m文件