ビルド フェーズで 1 つまたは複数の個々のファイルに -fno-objc-arc フラグを追加すると、MyProject-Prefix.pch ファイルが非 ARC モードになり、「warning: no 'assign', 'retain. '、または 'copy' 属性が指定されている - 'assign' と見なされます" がスローされます。
MyProject-Prefix.pch のコンパイルからの clang ログ出力を次に示します。ご覧のとおり、-fobjc-arc フラグが表示されますが、後で -no-fobjc-arc が追加されます。これは ARC をオーバーライドすると想定しています。これは、ビルド フェーズで単一の .m ソース ファイルに -fno-objc-arc を追加した場合にのみ発生します (ARC ファイルと非 ARC ファイルを混在させる場合の標準的なアドバイス)。
何か案は？
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -x objective-c-header -arch i386 -fmessage-length=0 -std=gnu99 -fobjc-arc -Wno-trigraphs -fpascal-strings -O0 -Wno-missing-field-initializers -Wno-missing-prototypes -Wreturn-type -Wno-implicit-atomic-properties -Wformat -Wno-missing-braces -Wparentheses -Wswitch -Wno-unused-function -Wno-unused-label -Wno-unused-parameter -Wunused-variable -Wunused-value -Wno-uninitialized -Wno-unknown-pragmas -Wno-shadow -Wno-four-char-constants -Wno-sign-compare -Wno-shorten-64-to-32 -Wpointer-sign -Wno-newline-eof -Wno-selector -Wno-strict-selector-match -Wno-undeclared-selector -Wno-deprecated-implementations -DDEBUG -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.1.sdk -fexceptions -fasm-blocks -Wprotocol -Wdeprecated-declarations -mmacosx-version-min=10.6 -g -Wno-conversion -Wno-sign-conversion -fobjc-abi-version=2 -fobjc-legacy-dispatch "-DIBOutlet=__attribute__((iboutlet))" "-DIBOutletCollection(ClassName)=__attribute__((iboutletcollection(ClassName)))" "-DIBAction=void)__attribute__((ibaction)" -D__IPHONE_OS_VERSION_MIN_REQUIRED=50100 -iquote /Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Intermediates/MyProject.build/Debug-iphonesimulator/MyProject.build/MyProject-generated-files.hmap -I/Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Intermediates/MyProject.build/Debug-iphonesimulator/MyProject.build/MyProject-own-target-headers.hmap -I/Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Intermediates/MyProject.build/Debug-iphonesimulator/MyProject.build/MyProject-all-target-headers.hmap -iquote /Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Intermediates/MyProject.build/Debug-iphonesimulator/MyProject.build/MyProject-project-headers.hmap -iquoteOAuth2Client -iquoteOAuth2Client/Sources -iquoteOAuth2Client/Sources/OAuth2Client -I/Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Products/Debug-iphonesimulator/include -I../../Source/facebook-ios-sdk/src -I/Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Products/Debug-iphonesimulator/../three20 -I/Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Products/Debug-iphonesimulator/../../three20 -I../../Source/three20/Build/Products/three20 -I/Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Intermediates/MyProject.build/Debug-iphonesimulator/MyProject.build/DerivedSources/i386 -I/Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Intermediates/MyProject.build/Debug-iphonesimulator/MyProject.build/DerivedSources -F/Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Products/Debug-iphonesimulator -F/Users/steve/Desktop/MyProject/YelpAPI/Frameworks -fno-objc-arc --serialize-diagnostics /Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Intermediates/PrecompiledHeaders/MyProject-Prefix-eouuweehlrhtjxdsrgwseamnhnna/MyProject-Prefix.pch.dia -c /Users/steve/Desktop/MyProject/MyProject/MyProject-Prefix.pch -o /Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Intermediates/PrecompiledHeaders/MyProject-Prefix-eouuweehlrhtjxdsrgwseamnhnna/MyProject-Prefix.pch.pth -MMD -MT dependencies -MF /Users/steve/Library/Developer/Xcode/DerivedData/MyProject-ajtusdfivjqtabgvzfuzqifdjuis/Build/Intermediates/PrecompiledHeaders/MyProject-Prefix-eouuweehlrhtjxdsrgwseamnhnna/MyProject-Prefix.pch.d