Error map

Error: Couldn't resolve the package Dart: Error: Couldn't resolve the package 'x' in 'package:x/x.dart'

Flutter / Dart · layer 1, On your device

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Error: Couldn't resolve the package — Dart: Error: Couldn't resolve the package 'x' in 'package:x/x.dart' (Flutter / Dart)Error: Coul…Null check operator used on a null value — Dart/Flutter: Null check operator used on a null value (Flutter / Dart)Null check operator…The argument type can't be assigned to the parameter type — Dart: The argument type 'String?' can't be assigned to the parameter type 'String' (Flutter / Dart)The argument type c…Non-nullable instance field must be initialized — Dart: Non-nullable instance field 'name' must be initialized. Try adding an initializer expression, or a generative constructor that initializes it, or mark it 'late' (Flutter / Dart)Non-nullable instan…type '_InternalLinkedHashMap' is not a subtype of type 'List<dynamic>' — Dart: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'List<dynamic>' in type cast (Flutter / Dart)type '_InternalLink…The current Dart SDK version is x; package requires SDK >= y — Dart pub: The current Dart SDK version is 2.19.0. Because app requires SDK version >=3.0.0 <4.0.0, version solving failed (Flutter / Dart)The current Dart SD…Bad state: No element — Dart: Bad state: No element — .first, .last or .single on an empty list (Flutter / Dart)Bad state: No eleme…RangeError (index): Invalid value — Dart: RangeError (index): Invalid value: Valid value range is empty: 0 (Flutter / Dart)RangeError (index):…FormatException: Unexpected character — Dart: FormatException: Unexpected character (at character 1) <!DOCTYPE html> — jsonDecode of an HTML page (Flutter / Dart)FormatException: Un…Bad state: Stream has already been listened to — Dart: Bad state: Stream has already been listened to (Flutter / Dart)Bad state: Stream h…version solving failed (pub get) — Dart pub: Because app depends on intl ^0.19.0 and flutter_localizations from sdk depends on intl 0.18.1, version solving failed (Flutter / Dart)version solving fai…The getter/method isn't defined for the type — Dart: The getter 'name' isn't defined for the type 'User' / The method 'foo' isn't defined for the class (Flutter / Dart)The getter/method i…Illegal argument in isolate message: object is unsendable — Dart: Invalid argument(s): Illegal argument in isolate message: object is unsendable - Library:'dart:async' Class: _Future@4048458 (Flutter / Dart)Illegal argument in…A RenderFlex overflowed — Flutter: A RenderFlex overflowed by x pixels on the right/bottom (Flutter / Dart)A RenderFlex overfl…setState() called after dispose() — Flutter: setState() called after dispose(): _MyState#1a2b3 (lifecycle state: defunct, not mounted) (Flutter / Dart)setState() called a…TS2322 — TS2322: Type 'X' is not assignable to type 'Y' (TypeScript)TS2322Cannot convert value of type — Swift: Cannot convert value of type 'X' to expected argument type 'Y' (iOS)Cannot convert valu…LateInitializationError: Field has not been initialized — Dart: LateInitializationError: Field 'controller' has not been initialized (Flutter / Dart)LateInitializationE…The property/method can't be unconditionally accessed because the receiver can be null — Dart: The property 'length' can't be unconditionally accessed because the receiver can be 'null' (Flutter / Dart)The property/method…type 'Null' is not a subtype of type 'String' — Dart: type 'Null' is not a subtype of type 'String' in type cast (Flutter / Dart)type 'Null' is not …The named parameter is required, but there's no corresponding argument — Dart: The named parameter 'key' is required, but there's no corresponding argument (Flutter / Dart)The named parameter…BoxConstraints forces an infinite width — Flutter: BoxConstraints forces an infinite width. These invalid constraints were provided to RenderStack's layout() function (TextField in a Row) (Flutter / Dart)BoxConstraints forc…Cleartext HTTP traffic not permitted — Flutter (Android): java.io.IOException: Cleartext HTTP traffic to api.example.com not permitted (Flutter / Dart)Cleartext HTTP traf…Android license status unknown / licenses not accepted — flutter doctor: Android license status unknown. Run `flutter doctor --android-licenses` to accept the SDK licenses (Flutter / Dart)Android license sta…SocketException: Failed host lookup — Flutter: Unhandled Exception: SocketException: Failed host lookup: 'api.example.com' (OS Error: No address associated with hostname, errno = 7) (Flutter / Dart)SocketException: Fa…setState() or markNeedsBuild() called during build — Flutter: setState() or markNeedsBuild() called during build. This widget cannot be marked as needing to build because the framework is already in the process of building widgets (Flutter / Dart)setState() or markN…A Ticker was active when the State was disposed — Flutter: _HomeState#abc(ticker active) was disposed with an active Ticker. State.dispose() implementations must call dispose() on all their AnimationControllers (Flutter / Dart)A Ticker was active…CocoaPods compatible versions — CocoaPods could not find compatible versions for pod (iOS)CocoaPods compatibl…No such module — Swift: No such module 'X' (module not found) (iOS)No such moduleUnable to find a specification — [!] Unable to find a specification for `X` depended upon by `Y` (iOS)Unable to find a sp…Looking up a deactivated widget's ancestor is unsafe — Flutter: Looking up a deactivated widget's ancestor is unsafe. At this point the state of the widget's element tree is no longer stable (Flutter / Dart)Looking up a deacti…

Directly related (12)

Null check operator used on a null valueFlutter / Dart

Dart/Flutter: Null check operator used on a null value

The ! operator was applied to a variable that was null at runtime.

The argument type can't be assigned to the parameter typeFlutter / Dart

Dart: The argument type 'String?' can't be assigned to the parameter type 'String'

You passed a value whose type does not match what the function parameter requires.

Non-nullable instance field must be initializedFlutter / Dart

Dart: Non-nullable instance field 'name' must be initialized. Try adding an initializer expression, or a generative constructor that initializes it, or mark it 'late'

With null safety every non-nullable field needs a value by the end of construction.

type '_InternalLinkedHashMap' is not a subtype of type 'List<dynamic>'Flutter / Dart

Dart: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'List<dynamic>' in type cast

JSON decoded to a Map but your code expected a List (or the other way round).

The current Dart SDK version is x; package requires SDK >= yFlutter / Dart

Dart pub: The current Dart SDK version is 2.19.0. Because app requires SDK version >=3.0.0 <4.0.0, version solving failed

A package (or your own pubspec) requires a newer Dart SDK than the one your Flutter installation provides.

Bad state: No elementFlutter / Dart

Dart: Bad state: No element — .first, .last or .single on an empty list

You called `.first`, `.last`, `.single` or `.reduce` on an empty collection.

RangeError (index): Invalid valueFlutter / Dart

Dart: RangeError (index): Invalid value: Valid value range is empty: 0

A list or string was indexed outside its bounds, often an empty list or an off-by-one in `itemBuilder`.

FormatException: Unexpected characterFlutter / Dart

Dart: FormatException: Unexpected character (at character 1) <!DOCTYPE html> — jsonDecode of an HTML page

`jsonDecode` received something that is not JSON, commonly an HTML error page, an empty string, or a plain-text message.

Bad state: Stream has already been listened toFlutter / Dart

Dart: Bad state: Stream has already been listened to

A single-subscription stream was listened to twice, for instance by two `StreamBuilder`s or after a rebuild.

version solving failed (pub get)Flutter / Dart

Dart pub: Because app depends on intl ^0.19.0 and flutter_localizations from sdk depends on intl 0.18.1, version solving failed

`flutter pub get` cannot find a set of package versions that satisfy every dependency's constraints.

The getter/method isn't defined for the typeFlutter / Dart

Dart: The getter 'name' isn't defined for the type 'User' / The method 'foo' isn't defined for the class

The analyzer cannot find that property or method on the object's static type.

Illegal argument in isolate message: object is unsendableFlutter / Dart

Dart: Invalid argument(s): Illegal argument in isolate message: object is unsendable - Library:'dart:async' Class: _Future@4048458

You tried to send an object (closure, Future, socket, platform object) to another isolate that cannot be copied.

Two steps away (18)

A RenderFlex overflowedFlutter / Dart

Flutter: A RenderFlex overflowed by x pixels on the right/bottom

A Row or Column’s children need more space than available, so Flutter draws the yellow-black overflow stripes.

setState() called after dispose()Flutter / Dart

Flutter: setState() called after dispose(): _MyState#1a2b3 (lifecycle state: defunct, not mounted)

An async callback (network, timer, stream) finished after the widget was removed and then called setState.

TS2322TypeScript

TS2322: Type 'X' is not assignable to type 'Y'

You assigned a value whose type doesn’t match the declared type of the variable, property or return value.

Cannot convert value of typeiOS

Swift: Cannot convert value of type 'X' to expected argument type 'Y'

The value’s type doesn’t match what the function or property expects.

LateInitializationError: Field has not been initializedFlutter / Dart

Dart: LateInitializationError: Field 'controller' has not been initialized

A `late` variable was read before it was assigned.

The property/method can't be unconditionally accessed because the receiver can be nullFlutter / Dart

Dart: The property 'length' can't be unconditionally accessed because the receiver can be 'null'

With null safety you used `.` on a nullable value; Dart requires a null check first.

type 'Null' is not a subtype of type 'String'Flutter / Dart

Dart: type 'Null' is not a subtype of type 'String' in type cast

A value that was `null` at runtime was cast or used as a non-nullable type, most often when parsing JSON.

The named parameter is required, but there's no corresponding argumentFlutter / Dart

Dart: The named parameter 'key' is required, but there's no corresponding argument

A constructor or function marked `required` for a parameter was called without it.

BoxConstraints forces an infinite widthFlutter / Dart

Flutter: BoxConstraints forces an infinite width. These invalid constraints were provided to RenderStack's layout() function (TextField in a Row)

A widget that needs a finite width, like a `TextField` or `Container` with no size, was placed where the parent offers unlimited…

Cleartext HTTP traffic not permittedFlutter / Dart

Flutter (Android): java.io.IOException: Cleartext HTTP traffic to api.example.com not permitted

Android 9+ blocks plain `http://` requests by default; the app must use HTTPS or explicitly allow cleartext for that host.

Android license status unknown / licenses not acceptedFlutter / Dart

flutter doctor: Android license status unknown. Run `flutter doctor --android-licenses` to accept the SDK licenses

The Android SDK licenses have not been accepted, so builds cannot download or use SDK components.

SocketException: Failed host lookupFlutter / Dart

Flutter: Unhandled Exception: SocketException: Failed host lookup: 'api.example.com' (OS Error: No address associated with hostname, errno = 7)

The app could not resolve or reach the server: no internet, wrong host name, DNS failure, or missing network permission.

setState() or markNeedsBuild() called during buildFlutter / Dart

Flutter: setState() or markNeedsBuild() called during build. This widget cannot be marked as needing to build because the framework is already in the process of building widgets

State was changed while Flutter was building widgets, for example calling `setState` or a notifier from inside `build`.

A Ticker was active when the State was disposedFlutter / Dart

Flutter: _HomeState#abc(ticker active) was disposed with an active Ticker. State.dispose() implementations must call dispose() on all their AnimationControllers

An `AnimationController` was still running when its `State` was disposed, because `dispose()` did not release it.

CocoaPods compatible versionsiOS

CocoaPods could not find compatible versions for pod

pod install can’t satisfy the version constraints — outdated spec repo, a higher deployment target required, or two pods needing…

No such moduleiOS

Swift: No such module 'X' (module not found)

Xcode can’t find a Swift package, pod or framework you import.

Unable to find a specificationiOS

[!] Unable to find a specification for `X` depended upon by `Y`

CocoaPods can’t find the pod (or version) in its spec repos — stale local specs, a private spec repo not added, or a typo.

Looking up a deactivated widget's ancestor is unsafeFlutter / Dart

Flutter: Looking up a deactivated widget's ancestor is unsafe. At this point the state of the widget's element tree is no longer stable

You used a `BuildContext` after its widget was removed from the tree — typically after an `await` when the user already navigated…