最新的Xcode 9.2 9C40b中：
去编译之前 swift代码出错：
/Users/crifan/dev/dev_root/daryun/Projects/Qoros/QorosSales/Sourcecode/SalesAppiOS/SalesApp/SearchCustomerViewController.swift:10:8: Module compiled with Swift 4.0.1 cannot be imported in Swift 3.2.3: /Users/crifan/dev/dev_root/daryun/Projects/Qoros/QorosSales/Sourcecode/SalesAppiOS/Carthage/Build/iOS/Cartography.framework/Modules/Cartography.swiftmodule/arm64.swiftmodule
之前就遇到：
【未解决】Xcode换9.2后代码编译报错：Module compiled with Swift 4.0 cannot be imported in Swift 3.2.3 – 在路上
但是没解决。
此处也看到项目配置中的是：
用的是swift 3.2.3的编译器
看来错误原因是：
Carthage去编译出来的库，是用的swift 4.0.1去编译的
此处或许终极的解决办法是：
把此处的swift从3.2.3换成4.0.1？
最后不行再去试试这个办法。
现在再去试试：
rm -rf ~/Library/Caches/org.carthage.CarthageKit/DerivedData carthage update --platform iOS --no-use-binaries
结果找不到entry？
➜ SalesAppiOS git:(master) carthage update --platform iOS --no-use-binaries No entry found for dependency –-no-use-binaries in Cartfile. ➜ SalesAppiOS git:(master) carthage --help Unrecognized command: '--help'. See `carthage help`. ➜ SalesAppiOS git:(master) carthage help Available commands: archive Archives built frameworks into a zip that Carthage can use bootstrap Check out and build the project's dependencies build Build the project's dependencies checkout Check out the project's dependencies copy-frameworks In a Run Script build phase, copies each framework specified by a SCRIPT_INPUT_FILE environment variable into the built app bundle fetch Clones or fetches a Git repository ahead of time help Display general or command-specific help outdated Check for compatible updates to the project's dependencies update Update and rebuild the project's dependencies version Display the current version of Carthage ➜ SalesAppiOS git:(master) carthage help update Update and rebuild the project's dependencies [--no-checkout] skip the checking out of dependencies after updating [--no-build] skip the building of dependencies after updating (ignored if --no-checkout option is present) [--verbose] print xcodebuild output inline (ignored if --no-build option is present) [--log-path (string)] path to the xcode build output. A temporary file is used by default [--configuration (string)] the Xcode configuration to build (ignored if --no-build option is present) [--platform (platform)] the platforms to build for (one of 'all', 'macOS', 'iOS', 'watchOS', 'tvOS', or comma-separated values of the formers except for 'all') (ignored if --no-build option is present) [--toolchain (string)] the toolchain to build with [--derived-data (string)] path to the custom derived data folder [--cache-builds] use cached builds when possible [--use-ssh] use SSH for downloading GitHub repositories [--use-submodules] add dependencies as Git submodules [--no-use-binaries] check out dependency repositories even when prebuilt frameworks exist, disabled if --use-submodules option is present (ignored if --no-build or --toolchain option is present) [--color (color)] whether to apply color and terminal formatting (one of 'auto', 'always', or 'never') [--project-directory (string)] the directory containing the Carthage project [[]] the dependency names to update, checkout and build ➜ SalesAppiOS git:(master)
把
<span style=”font-size: 12px; color: rgb(51, 51, 51); font-family: Monaco;”–<no-use-binaries
换个位置，放在update前面就可以了：
➜ SalesAppiOS git:(master) carthage update --no-use-binaries --platform iOS *** Fetching Cartography *** Fetching MGSwipeTableCell *** Fetching Alamofire ...
然后就是漫长的等待了。
期间切换网络所以报错：
A shell task (/usr/bin/env git fetch –prune –quiet origin refs/tags/*:refs/tags/* +refs/heads/*:refs/heads/* (launched in /Users/crifan/Library/Caches/org.carthage.CarthageKit/dependencies/Kingfisher)) failed with exit code 128:
fatal: unable to access ‘https://github.com/onevcat/Kingfisher.git/‘: LibreSSL SSL_connect: SSL_ERROR_SYSCALL in connection to github.com:443
继续重新运行。
Swift 4.0.1 cannot be 3.2.3
Swift 4.0.1 cannot be
swift4 – Module compiled with Swift 4.0 cannot be imported in Swift 3.2.1 – Stack Overflow
那抽空试试，换成4.0.1，看看是否有其他问题
希望不要是代码都要改成最新的4.0.1，那就麻烦了。
去看看build编译期间的log：
*** xcodebuild output can be found in /var/folders/46/2hjxz38n22n3ypp_5f6_p__00000gn/T/carthage-xcodebuild.xLepXw.log
期间调用的swift的编译器是：
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc
所以自己去看看此处swiftc版本号是多少
可以看到：
➜ ~ which swiftc /usr/bin/swiftc ➜ ~ where swiftc /usr/bin/swiftc ➜ ~ swiftc --version Apple Swift version 4.0.3 (swiftlang-900.0.74.1 clang-900.0.39.2) Target: x86_64-apple-macosx10.9 ➜ ~ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc --version Apple Swift version 4.0.3 (swiftlang-900.0.74.1 clang-900.0.39.2) Target: x86_64-apple-macosx10.9 ➜ ~ ll /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ total 190432 -rwxr-xr-x 1 root wheel 33K 11 17 16:51 ar -rwxr-xr-x 1 root wheel 27K 11 17 16:51 as -rwxr-xr-x 1 root wheel 18K 11 17 16:51 asa -rwxr-xr-x 1 root wheel 211K 11 17 16:51 bison -rwxr-xr-x 1 root wheel 146K 11 17 16:51 bitcode_strip lrwxr-xr-x 1 root wheel 5B 12 13 11:53 c++ -> clang -rwxr-xr-x 1 root wheel 23K 11 17 16:51 c89 -rwxr-xr-x 1 root wheel 23K 11 17 16:51 c99 lrwxr-xr-x 1 root wheel 5B 12 13 11:53 cc -> clang -rwxr-xr-x 1 root wheel 65M 11 17 16:51 clang lrwxr-xr-x 1 root wheel 5B 12 13 11:53 clang++ -> clang -rwxr-xr-x 1 root wheel 117K 11 17 16:51 cmpdylib -rwxr-xr-x 1 root wheel 142K 11 17 16:51 codesign_allocate -rwxr-xr-x 1 root wheel 3.5M 11 17 16:51 coremlcompiler -rwxr-xr-x 1 root wheel 3.3K 11 7 08:28 cpp -rwxr-xr-x 1 root wheel 27K 11 17 16:51 ctags -rwxr-xr-x 1 root wheel 142K 11 17 16:51 ctf_insert lrwxr-xr-x 1 root wheel 13B 12 13 11:53 dsymutil -> llvm-dsymutil -rwxr-xr-x 1 root wheel 1.1M 11 17 16:51 dsymutil-classic -rwxr-xr-x 1 root wheel 983K 11 17 16:51 dwarfdump -rwxr-xr-x 1 root wheel 180K 11 17 16:51 dyldinfo -rwxr-xr-x 2 root wheel 564K 11 17 16:51 flex -rwxr-xr-x 2 root wheel 564K 11 17 16:51 flex++ lrwxr-xr-x 1 root wheel 8B 12 13 11:53 gcov -> llvm-cov -rwxr-xr-x 2 root wheel 139K 11 17 16:51 gm4 -rwxr-xr-x 1 root wheel 89K 11 17 16:51 gperf -rwxr-xr-x 1 root wheel 64K 11 17 16:51 indent -rwxr-xr-x 1 root wheel 134K 11 17 16:51 install_name_tool -rwxr-xr-x 1 root wheel 1.8M 11 17 16:51 ld -rwxr-xr-x 1 root wheel 230B 11 7 09:38 lex -rwxr-xr-x 1 root wheel 151K 11 17 16:51 libtool -rwxr-xr-x 1 root wheel 64K 11 17 16:51 lipo -rwxr-xr-x 1 root wheel 2.6M 11 17 16:51 llvm-cov -rwxr-xr-x 1 root wheel 22M 11 17 16:51 llvm-dsymutil -rwxr-xr-x 1 root wheel 2.4M 11 17 16:51 llvm-dwarfdump -rwxr-xr-x 1 root wheel 7.7M 11 17 16:51 llvm-nm -rwxr-xr-x 1 root wheel 9.1M 11 17 16:51 llvm-objdump -rwxr-xr-x 1 root wheel 32K 11 17 16:51 llvm-otool -rwxr-xr-x 1 root wheel 551K 11 17 16:51 llvm-profdata -rwxr-xr-x 1 root wheel 2.2M 11 17 16:51 llvm-size -rwxr-xr-x 1 root wheel 3.5K 11 7 09:41 lorder -rwxr-xr-x 2 root wheel 139K 11 17 16:51 m4 -rwxr-xr-x 1 root wheel 7.4K 11 7 09:40 mig lrwxr-xr-x 1 root wheel 7B 12 13 11:53 nm -> llvm-nm -rwxr-xr-x 1 root wheel 130K 11 17 16:51 nm-classic -rwxr-xr-x 1 root wheel 159K 11 17 16:51 nmedit lrwxr-xr-x 1 root wheel 12B 12 13 11:53 objdump -> llvm-objdump lrwxr-xr-x 1 root wheel 10B 12 13 11:53 otool -> llvm-otool -rwxr-xr-x 1 root wheel 625K 11 17 16:51 otool-classic -rwxr-xr-x 1 root wheel 126K 11 17 16:51 pagestuff lrwxr-xr-x 1 root wheel 7B 12 13 11:53 ranlib -> libtool -rwxr-xr-x 1 root wheel 59K 11 17 16:51 rebase -rwxr-xr-x 1 root wheel 196K 11 17 16:51 redo_prebinding -rwxr-xr-x 1 root wheel 72K 11 17 16:51 rpcgen -rwxr-xr-x 1 root wheel 44K 11 17 16:51 segedit lrwxr-xr-x 1 root wheel 9B 12 13 11:53 size -> llvm-size -rwxr-xr-x 1 root wheel 117K 11 17 16:51 size-classic -rwxr-xr-x 1 root wheel 118K 11 17 16:51 strings -rwxr-xr-x 1 root wheel 185K 11 17 16:51 strip -rwxr-xr-x 1 root wheel 72M 11 17 16:51 swift -rwxr-xr-x 1 root wheel 4.5M 11 17 16:51 swift-build -rwxr-xr-x 1 root wheel 346K 11 17 16:51 swift-build-tool -rwxr-xr-x 1 root wheel 376K 11 17 16:51 swift-demangle -rwxr-xr-x 1 root wheel 4.5M 11 17 16:51 swift-package -rwxr-xr-x 1 root wheel 4.5M 11 17 16:51 swift-run -rwxr-xr-x 1 root wheel 52K 11 17 16:51 swift-stdlib-tool -rwxr-xr-x 1 root wheel 4.5M 11 17 16:51 swift-test lrwxr-xr-x 1 root wheel 5B 12 13 11:53 swiftc -> swift -rwxr-xr-x 1 root wheel 11M 11 17 16:51 tapi -rwxr-xr-x 1 root wheel 32K 11 17 16:51 unifdef -rwxr-xr-x 1 root wheel 2.9K 11 7 09:41 unifdefall -rwxr-xr-x 1 root wheel 49K 11 17 16:51 unwinddump -rwxr-xr-x 1 root wheel 135B 11 7 09:42 yacc ➜ ~ ll /usr/bin/swiftc -rwxr-xr-x 1 root wheel 18K 12 2 04:45 /usr/bin/swiftc ➜ ~ ll /usr/bin/swift* -rwxr-xr-x 1 root wheel 18K 12 2 04:45 /usr/bin/swift -rwxr-xr-x 1 root wheel 18K 12 2 04:45 /usr/bin/swiftc
结果是：
默认的swiftc是4.0.3的版本
所在路径是：/usr/bin/
而此处编译所用的swiftc是在：
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/
且是个软连接，真正指向的是同目录下的：
（70多M的）swift
不过这个swift（或swiftc）也同样都是4.0.3
都和上面报错的4.0.1不一致：
估计是：
之前报错的是用之前（9.1 beta）Xcode版本编译的
而此处Xcode是最新的9.2，估计对应内部的swiftc的4.0.3版本
Swift 4.0.1 cannot be 3.2.3
Swift 4.0.3 cannot be 3.2.3
realm-cocoa/CHANGELOG.md at master · realm/realm-cocoa
https://github.com/realm/realm-cocoa/blob/master/CHANGELOG.md
对于此处编译很慢的Realm库来说，人家预编译好的framerowk已经包含了：Swift 3.2.3 and 4.0.3
Swift 4.0.3 vs 3.2.3 差别
等了半天终于编译完成：
➜ SalesAppiOS git:(master) carthage update --no-use-binaries --platform iOS *** Fetching Cartography *** Fetching MGSwipeTableCell *** Fetching Alamofire *** Fetching TextFieldEffects *** Fetching SwiftyJSON *** Fetching KMPlaceholderTextView *** Fetching realm-cocoa *** Fetching SwiftHEXColors *** Fetching SwiftHTTPStatusCodes *** Fetching ActionSheetPicker-3.0 *** Fetching Kingfisher *** Fetching Charts *** Fetching SwiftKeychainWrapper *** Fetching DLRadioButton *** Fetching XCGLogger *** Checking out Cartography at "1.1.0" *** Checking out DLRadioButton at "1.4.11" *** Checking out Charts at "v3.0.4" *** Checking out SwiftKeychainWrapper at "2.2.1" *** Checking out Kingfisher at "3.13.1" *** Checking out ActionSheetPicker-3.0 at "2.3.0" *** Checking out SwiftHTTPStatusCodes at "3.2.0" *** Checking out SwiftHEXColors at "1.1.1" *** Checking out realm-cocoa at "v3.0.2" *** Checking out KMPlaceholderTextView at "1.3.0" *** Checking out SwiftyJSON at "4.0.0" *** Checking out TextFieldEffects at "1.4.0" *** Checking out Alamofire at "4.6.0" *** Checking out MGSwipeTableCell at "1.6.6" *** Checking out XCGLogger at "Version_4.0.0" *** xcodebuild output can be found in /var/folders/46/2hjxz38n22n3ypp_5f6_p__00000gn/T/carthage-xcodebuild.xLepXw.log *** Building scheme "CoreActionSheetPicker" in ActionSheetPicker-3.0.xcworkspace *** Building scheme "Alamofire iOS" in Alamofire.xcworkspace *** Building scheme "Cartography-iOS" in Cartography.xcworkspace *** Building scheme "Charts" in Charts.xcodeproj *** Building scheme "DLRadioButton" in DLRadioButton.xcodeproj *** Building scheme "Kingfisher" in Kingfisher.xcworkspace *** Building scheme "KMPlaceholderTextView" in KMPlaceholderTextView.xcodeproj *** Building scheme "MGSwipeTableCell" in MGSwipeTableCell.xcodeproj *** Building scheme "Realm" in Realm.xcworkspace *** Building scheme "RealmSwift" in Realm.xcworkspace *** Building scheme "SwiftHEXColors" in SwiftHEXColors.xcodeproj *** Building scheme "HTTPStatusCodes" in HTTPStatusCodes.xcodeproj *** Building scheme "SwiftKeychainWrapper" in SwiftKeychainWrapper.xcodeproj *** Building scheme "SwiftyJSON iOS" in SwiftyJSON.xcworkspace *** Building scheme "TextFieldEffects" in TextFieldEffects.xcodeproj *** Building scheme "XCGLogger (iOS)" in XCGLogger.xcodeproj
然后再去Xcode中编译链接看看
结果出现其他错误：
【已解决】Swift代码JSON出错：Call can throw, but it is not marked with ‘try’ and the error is not handled
然后就真的可以正常编译和链接，解决了此问题了，可以正常启动app了：
【总结】
此处Xcode链接之所以报错：
Module compiled with Swift 4.0.1 cannot be imported in Swift 3.2.3
的原因是：
Xcode从9.1 beta升级到了9.2，导致之前用carthage编译好的库和现在项目设置中所指定的swiftc 3.2.3不兼容了。
解决办法是：
rm -rf ~/Library/Caches/org.carthage.CarthageKit/DerivedData carthage update --no-use-binaries --platform iOS
即可重新编译出符合要求的库了，然后Xcode正常使用就没问题了。
转载请注明：在路上 » 【已解决】Xcode编译出错：Module compiled with Swift 4.0.1 cannot be imported in Swift 3.2.3