Can't run hello-world Flutter app in Simulator: “Swift Language Version” (SWIFT_VERSION) is required to be configured correctly for targets which use Swift.

[filiph]

Steps to Reproduce

1. Open IntelliJ IDEA
2. Create new Flutter project
3. Select to use Swift instead of Obj-C (and Kotlin instead of Java)
4. Open iOS Simulator
5. Run in debug mode

Logs

$ flutter run
Launching lib/main.dart on iPhone 5s in debug mode...
Running Xcode build...                                0.6s
Failed to build iOS app
Error output from Xcode build:
↳
    ** CLEAN FAILED **


    The following build commands failed:
    	Check dependencies
    (1 failure)
    ** BUILD FAILED **


    The following build commands failed:
    	Check dependencies
    (1 failure)
Xcode's output:
↳
    Build settings from command line:
        ARCHS = x86_64
        BUILD_DIR = /Users/filiph/dev/scifi_ui/build/ios
        ONLY_ACTIVE_ARCH = YES
        SDKROOT = iphonesimulator10.3

    === CLEAN TARGET Runner OF PROJECT Runner WITH CONFIGURATION Debug ===

    Check dependencies
    “Swift Language Version” (SWIFT_VERSION) is required to be configured correctly for targets which use Swift. Use the [Edit > Convert > To Current Swift Syntax…] menu to choose a Swift version or use the Build Settings editor to configure the build setting directly.

    === BUILD TARGET Runner OF PROJECT Runner WITH CONFIGURATION Debug ===

    Check dependencies
    “Swift Language Version” (SWIFT_VERSION) is required to be configured correctly for targets which use Swift. Use the [Edit > Convert > To Current Swift Syntax…] menu to choose a Swift version or use the Build Settings editor to configure the build setting directly.

Could not build the application for the simulator.
Error launching application on iPhone 5s.

---

$ flutter analyze
Analyzing /Users/filiph/dev/scifi_ui...
No issues found!
Ran in 4.3s

Flutter Doctor

$ flutter doctor
[✓] Flutter (on Mac OS X 10.12.6 16G1036, locale en-US, channel master)
    • Flutter at /Users/filiph/dev/flutter
    • Framework revision 0350c9ecff (85 minutes ago), 2017-12-07 09:32:23 -0800
    • Engine revision f888186e50
    • Tools Dart version 1.25.0-dev.11.0
    • Engine Dart version 2.0.0-edge.e7b7b68ef6e7b1e5df379b628134764c489901dc

[✓] Android toolchain - develop for Android devices (Android SDK 25.0.3)
    • Android SDK at /Users/filiph/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-25, build-tools 25.0.3
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[✓] iOS toolchain - develop for iOS devices (Xcode 8.3.3)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 8.3.3, Build version 8E3004b
    • ios-deploy 1.9.2
    • CocoaPods version 1.2.1

[-] Android Studio
    • Android Studio at /Applications/Android Studio - Canary.app/Contents
    ✗ Unable to find bundled Java version.
    • Try updating or re-installing Android Studio.

[✓] Android Studio (version 2.3)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Java version OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[✓] IntelliJ IDEA Community Edition (version 2017.2.5)
    • Flutter plugin version 17.0
    • Dart plugin version 172.4155.35

[✓] Connected devices
    • iPhone 5s • 1174F021-6AD2-4B98-B4AF-4AFAD670B531 • ios • iOS 10.3 (simulator)

For more information about diagnosing and reporting Flutter bugs, please see https://flutter.io/bug-reports/.

[filiph]

Xcode Version 8.3.3 (8E3004b)

[jcan37]

For anyone struggling to work around this, if you open up the Runner project in the ios folder in Xcode, under "Build Settings" you can set "Use Legacy Swift Language Version" to "Yes" and then you should be able to run the app. This link should help: https://stackoverflow.com/questions/41118912/use-legacy-swift-language-version-xcode-8-2

[madd86]

Anyone know how to fix it on Xcode 9.3.1?

[zoechi]

@madd86 have you tried flutter create with

[passsy]

I can verify that running flutter create -i swift fixes the problem. Actually it should be the default

[zoechi]

@passsy Swift introduces quite some application size penalty. I think this is why it isn't the default.

[zoechi]

@tvolkert

[Tonigt]

=== BUILD TARGET signalr_plugin OF PROJECT Pods WITH CONFIGURATION Debug ===
/Users/lihaoyutonight/.pub-cache/hosted/pub.flutter-io.cn/flutter_inappbrowser-1.2.1/ios/Classes/InAppBrowserFlutterPlugin.m:19:9: fatal error: 'flutter_inappbrowser/flutter_inappbrowser-Swift.h' file not found
#import <flutter_inappbrowser/flutter_inappbrowser-Swift.h>
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.