Flutter VSコード Unsupported operation: _ExplicitNamedTypeBuilder.registerInferredType

わけわかりません。

Launching lib\main.dart on Windows in debug mode...
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)

#9 IncrementalCompiler.computeDelta. (package:front_end/src/fasta/incremental_compiler.dart:407:33) #10 IncrementalCompiler.compile (package:vm/incremental_compiler.dart:68:50) #11 FrontendCompiler.compile (package:frontend_server/frontend_server.dart:572:11) #12 listenAndCompile. (package:frontend_server/frontend_server.dart:1210:11)

#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)

#10 IncrementalCompiler.compile (package:vm/incremental_compiler.dart:68:50) #11 FrontendCompiler.compile (package:frontend_server/frontend_server.dart:572:11) #12 listenAndCompile. (package:frontend_server/frontend_server.dart:1210:11)

the Dart compiler exited unexpectedly.
Exception: Unable to find suitable Visual Studio toolchain. Please run flutter doctor for more details.
Exited (sigterm)