Dart Analyzer has terminated (on updating extension)

[cornerplotter]

Bad state: No definition of type Future
#0 TypeProviderImpl._getClassElement (package:analyzer/src/dart/element/type_provider.dart:603)
#1 TypeProviderImpl.futureElement (package:analyzer/src/dart/element/type_provider.dart:271)
#2 TypeProviderImpl.futureDynamicType (package:analyzer/src/dart/element/type_provider.dart:261)
#3 LoadLibraryFunctionProvider._create (package:analyzer/src/dart/element/element.dart:7144)
#4 LoadLibraryFunctionProvider.getElement (package:analyzer/src/dart/element/element.dart:7131)
#5 LibraryElementImpl.loadLibraryFunction (package:analyzer/src/dart/element/element.dart:6085)
#6 BundleWriter._writeLoadLibraryFunctionReferences (package:analyzer/src/summary2/bundle_writer.dart:545)
#7 BundleWri…
[2:37:05 PM] [DartToolingDaemon] [Info] <== {"jsonrpc":"2.0","method":"streamNotify","params":{"streamId":"Service","eventKind":"ServiceUnregistered","eventData":{"service":"Lsp","method":"dart/textDocument/augmentation"},"timestamp":1774622225145}}
[2:37:05 PM] [Analyzer] [Warn] LSP Client closed (1 recent restarts recorded)
[2:37:05 PM] [Analyzer] [Info] Spawning C:\Users\RogerWhitehead\FlutterSDK\flutter\bin\cache\dart-sdk\bin\dart.exe with args ["language-server","--protocol=lsp","--client-id=VS-Code","--client-version=3.130.1"]
[2:37:05 PM] [Analyzer] [Info] PID: 50732
[2:37:05 PM] [Analyzer] [Info] ==> Content-Length: 6744
[2:37:05 PM] [Analyzer] [Info] ==> {"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":110148,"clientInfo":{"name":"Visual Studio Code","version":"1.113.0"},"locale":"en","rootPath":"c:\Users\...\AndroidStudioProjects\flutter-forms","rootUri":"file:///C%3A/Users/.../AndroidStudioProjects/flutter-forms","capabilities":{"workspace":{"applyEdit":true,"workspaceEdit":{"documentChanges":true,"resourceOperations":["create","rename","delete"],"failureHandling":"textOnlyTransactional","normalizesLineEndings":true,"changeAnnotationSupport":{"groupsOnLabel":true}},"configuration":true,"didChangeWatchedFiles":{"dynamicRegistration":true,"relativePatternSupport":true},"symbol":{"dynamicRegistration":true,"symbolKind":{"valueSet":[1,2,3,4,5,6…
[2:37:05 PM] [Analyzer] [Info] Analysis server exited (255, null)
[2:37:05 PM] [Analyzer] [Warn] Prompting to reload: (The Dart Analyzer has terminated. Please file an issue on GitHub with any error from the end of the log.) (actions: Restart Extension, Show Log)

• Dart 3.11.4 (stable) (Tue Mar 24 01:02:20 2026 -0700) on "windows_x64"
• on windows / "Windows 11 Pro" 10.0 (Build 26200)
• locale is en-GB

[FMorschel]

CC @DanTup

[DanTup]

@cornerplotter are you able to reproduce this, or did it just happen once?

In the title you mentioned updating the extension - do you mean the Dart extension for VS Code? (there hasn't been a stable update for this in a while, although there was an update a few days ago if you're on the pre-release version). Was there anything else you did around the time (or shortly before) this occurred? For example had you recently updated your Flutter SDK?

@scheglov are the summary files being read from here shipped with the SDK, or created from source the first time they're used? I ask because I saw some issues recently where opening VS Code would start the server, and then flutter would start updated the Dart SDK (causing various crashes as bits of the SDK were overwritten on disk). I'm wondering if this could be something like that (I have a fix for it, but it hasn't shipped yet).

[scheglov]

DAS builds summaries as necessary. We never use anything like that from the SDK. The exception here is just a sign that the SDK is incomplete, I don't think it is related to summaries.

[DanTup]

Ah, in that case my first guess would be that this is related to Dart-Code/Dart-Code#5971 where the server is starting up while Flutter is replacing the SDK, which can result in the SDK on disk not being complete, or failures to update some files because they're locked.

@cornerplotter if you continue to see this, I would try"

• closing all instances of VS Code (and any other tooling that may actively using the Dart/Flutter SDKs)
• delete the C:\Users\RogerWhitehead\FlutterSDK\flutter\bin\cache folder, which contains some components cached by the Flutter SDK (including the Dart SDK)
• re-open VS Code and you should see a notification about "Setting up the Flutter SDK" which may take a few minutes while it re-downloads the Dart SDK and other components into the cache

If the problem was caused by Dart-Code/Dart-Code#5971, the fix for that will ship soon (probably next week) which will hopefully prevent this kind of issue in the future.

Please let us know if things still don't work after following the steps above.

[cornerplotter]

Thanks all for your contributions. I'm new to VS Code & Flutter dev (a few months on-and-off), I finally got the thing to work (after closing VS Code, killing off likely processes, restarting VS Code) continually restarting the extension until it worked.

The error was inspired by (I think) flutter upgrade or possibly flutter outdated.

I'm very grateful for your time & expertise, will try to follow your breadcrumbs & learn more!

[DanTup]

@cornerplotter great, glad you got it working. If you recently had run flutter upgrade then I suspect that was the cause. Did you run it within VS Code just before the crash, or had you run it previously and then opened VS Code?

If you'd run it before opening VS Code, then I expect the fix for Dart-Code/Dart-Code#5971 to prevent this again. If you ran it while the editor was open, it's possible that could still be issues (in which case I'll do some testing to see if I can reproduce).