当创建一个项目，它立即给出以下错误Flutter医生-确定！
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Launching lib\main.dart on Android SDK built for x86 in debug mode...
Running Gradle task 'assembleDebug'...
Unhandled exception:
Crash when compiling null,
at character offset null:
Unsupported operation: _ExplicitNamedTypeBuilder.registerInferredType
#0      TypeBuilder.registerInferredType (package:front_end/src/fasta/builder/type_builder.dart:350:5)
#1      DeclaredSourceConstructorBuilder.finalizeSuperInitializingFormals.performRecoveryForErroneousCase (package:front_end/src/fasta/source/source_constructor_builder.dart:355:23)
#2      DeclaredSourceConstructorBuilder.finalizeSuperInitializingFormals (package:front_end/src/fasta/source/source_constructor_builder.dart:375:14)
#3      DeclaredSourceConstructorBuilder.inferFormalTypes (package:front_end/src/fasta/source/source_constructor_builder.dart:290:9)
#4      DeclaredSourceConstructorBuilder.inferTypes (package:front_end/src/fasta/source/source_constructor_builder.dart:263:5)
#5      InferableTypeBuilder.inferType (package:front_end/src/fasta/builder/omitted_type_builder.dart:149:19)
#6      SourceLoader.performTopLevelInference (package:front_end/src/fasta/source/source_loader.dart:2358:19)
#7      KernelTarget.buildOutlines.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:532:14)
<asynchronous suspension>
#8      withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#9      IncrementalCompiler.computeDelta.<anonymous closure> (package:front_end/src/fasta/incremental_compiler.dart:407:33)
<asynchronous suspension>
#10     IncrementalCompiler.compile (package:vm/incremental_compiler.dart:68:50)
<asynchronous suspension>
#11     FrontendCompiler.compile (package:frontend_server/frontend_server.dart:572:11)
<asynchronous suspension>
#12     listenAndCompile.<anonymous closure> (package:frontend_server/frontend_server.dart:1210:11)
<asynchronous suspension>

#0      TypeBuilder.registerInferredType (package:front_end/src/fasta/builder/type_builder.dart:350:5)
#1      DeclaredSourceConstructorBuilder.finalizeSuperInitializingFormals.performRecoveryForErroneousCase (package:front_end/src/fasta/source/source_constructor_builder.dart:355:23)
#2      DeclaredSourceConstructorBuilder.finalizeSuperInitializingFormals (package:front_end/src/fasta/source/source_constructor_builder.dart:375:14)
#3      DeclaredSourceConstructorBuilder.inferFormalTypes (package:front_end/src/fasta/source/source_constructor_builder.dart:290:9)
#4      DeclaredSourceConstructorBuilder.inferTypes (package:front_end/src/fasta/source/source_constructor_builder.dart:263:5)
#5      InferableTypeBuilder.inferType (package:front_end/src/fasta/builder/omitted_type_builder.dart:149:19)
#6      SourceLoader.performTopLevelInference (package:front_end/src/fasta/source/source_loader.dart:2358:19)
#7      KernelTarget.buildOutlines.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:532:14)
<asynchronous suspension>
#8      withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#9      IncrementalCompiler.computeDelta.<anonymous closure> (package:front_end/src/fasta/incremental_compiler.dart:407:33)
<asynchronous suspension>
#10     IncrementalCompiler.compile (package:vm/incremental_compiler.dart:68:50)
<asynchronous suspension>
#11     FrontendCompiler.compile (package:frontend_server/frontend_server.dart:572:11)
<asynchronous suspension>
#12     listenAndCompile.<anonymous closure> (package:frontend_server/frontend_server.dart:1210:11)
<asynchronous suspension>
the Dart compiler exited unexpectedly.
the Dart compiler exited unexpectedly.

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重新安装android studio没有帮助.
在我的情况下，这个页面的解决方案不起作用StatelessWidget : Classes can only extend other classes.dart(extends_non_class) - issue