报错内容

运行一个flutter项目突然报错：

Crash when compiling null, at character offset null: Null check operator used on a null value #0 InferableTypeBuilderMixin.type (package:front_end/src/fasta/builder/type_builder.dart:392:29)

全部报错信息如下：

/Volumes/huc/opt/fvm/current/bin/cache/dart-sdk/bin/dart --enable-asserts --pause_isolates_on_start --enable-vm-service:60501 /Volumes/huc/58housecommonLib/fair/example/lib/main.dart
The Dart VM service is listening on http://127.0.0.1:60501/i-DncDKjZNw=/

The Dart DevTools debugger and profiler is available at: http://127.0.0.1:60501/i-DncDKjZNw=/devtools/#/?uri=ws%3A%2F%2F127.0.0.1%3A60501%2Fi-DncDKjZNw%3D%2Fws
Crash when compiling null,
at character offset null:
Null check operator used on a null value
#0      InferableTypeBuilderMixin.type (package:front_end/src/fasta/builder/type_builder.dart:392:29)
#1      InferableTypeBuilder.inferType (package:front_end/src/fasta/builder/omitted_type_builder.dart:155:12)
#2      SourceLoader.performTopLevelInference (package:front_end/src/fasta/source/source_loader.dart:2358:19)
#3      KernelTarget.buildOutlines.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:532:14)
<asynchronous suspension>
#4      withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#5      IncrementalCompiler.computeDelta.<anonymous closure> (package:front_end/src/fasta/incremental_compiler.dart:407:33)
<asynchronous suspension>
#6      IncrementalCompiler.compile (package:vm/incremental_compiler.dart:68:50)
<asynchronous suspension>
#7      IncrementalCompilerWrapper.compileInternal (org-dartlang-kernel-service:///pkg/vm/bin/kernel_service.dart:345:28)
<asynchronous suspension>
#8      Compiler.compile.<anonymous closure> (org-dartlang-kernel-service:///pkg/vm/bin/kernel_service.dart:221:45)
<asynchronous suspension>
#9      _processLoadRequest (org-dartlang-kernel-service:///pkg/vm/bin/kernel_service.dart:914:37)
<asynchronous suspension>


#0      InferableTypeBuilderMixin.type (package:front_end/src/fasta/builder/type_builder.dart:392:29)
#1      InferableTypeBuilder.inferType (package:front_end/src/fasta/builder/omitted_type_builder.dart:155:12)
#2      SourceLoader.performTopLevelInference (package:front_end/src/fasta/source/source_loader.dart:2358:19)
#3      KernelTarget.buildOutlines.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:532:14)
<asynchronous suspension>
#4      withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#5      IncrementalCompiler.computeDelta.<anonymous closure> (package:front_end/src/fasta/incremental_compiler.dart:407:33)
<asynchronous suspension>
#6      IncrementalCompiler.compile (package:vm/incremental_compiler.dart:68:50)
<asynchronous suspension>
#7      IncrementalCompilerWrapper.compileInternal (org-dartlang-kernel-service:///pkg/vm/bin/kernel_service.dart:345:28)
<asynchronous suspension>
#8      Compiler.compile.<anonymous closure> (org-dartlang-kernel-service:///pkg/vm/bin/kernel_service.dart:221:45)
<asynchronous suspension>
#9      _processLoadRequest (org-dartlang-kernel-service:///pkg/vm/bin/kernel_service.dart:914:37)
<asynchronous suspension>


Process finished with exit code 252

检查配置

我运行的是fair 项目下的example工程
这是一个flutter app项目
所以这里建错target了

按照下面target 重新创建运行target

创建flutter app target 如下

重新点击debug 启动项目，

ok成功了

总结

本次记录这次fair项目example 实例运行过程，其中走了一些弯路，比如检查dart sdk 版本是不是之前有手动修改过，导致dart-sdk front-end 编译系统出问题了。 还切换了3.3.0 3.3.2 3.3.7等多个版本，删除~/.pub-cache,删除$FLUTTER_ROOT/bin/cache等重置flutter 环境都是报错， 最后发现是入口创建错了。 算是一个小失误，记录一下