# flutter pub run build_runner build --verbose --delete-conflicting-outputs 报错

[interfacekun]

#52 后续问题查找 [+52383 ms] "flutter run" took 52,814ms. [ +5 ms] pub finished with exit code 1 [ +1 ms] #0 throwToolExit (package:flutter_tools/src/base/common.dart:10:3) #1 _DefaultPub.interactively (package:flutter_tools/src/dart/pub.dart:416:7) #2 PackagesForwardCommand.runCommand (package:flutter_tools/src/commands/packages.dart:251:5) #3 FlutterCommand.run. (package:flutter_tools/src/runner/flutter_command.dart:1161:27) #4 AppContext.run. (package:flutter_tools/src/base/context.dart:150:19) #5 CommandRunner.runCommand (package:args/command_runner.dart:209:13) #6 FlutterCommandRunner.runCommand. (package:flutter_tools/src/runner/flutter_command_runner.dart:281:9) #7 AppContext.run. (package:flutter_tools/src/base/context.dart:150:19) #8 FlutterCommandRunner.runCommand (package:flutter_tools/src/runner/flutter_command_runner.dart:229:5) #9 run.. (package:flutter_tools/runner.dart:62:9) #10 AppContext.run. (package:flutter_tools/src/base/context.dart:150:19) #11 main (package:flutter_tools/executable.dart:94:3)

通过添加调试日志，发现两处空安全报错：

1. flutter/.pub-cache/hosted/pub.flutter-io.cn/fair_dart2dsl-1.0.1/lib/src/widget.dart
2. flutter/.pub-cache/hosted/pub.flutter-io.cn/fair_dart2dsl-1.0.1/lib/fairc.dart

[yancechen]

收到，我们优化一下这两处~~