jsonDecode returns String, not List

[imreallyliam]

Steps to Reproduce

1. Use jsonDecoder with List

Logs

https://paste.xeu100.com/?49310cd9a8bff62f#mUK+5HYLomwYfg4pyQLl3ukmkq8/REXAReAGny8nCVc=

Analyzing xid...

   info - This class (or a class which this class inherits from) is marked as '@immutable', but one or more of its instance fields are not final: AccountElement._accountId, AccountElement._email, AccountElement._website - lib\elements\AccountElement.dart:3:7 -
          must_be_immutable
   info - The value of the field '_accountId' isn't used - lib\elements\AccountElement.dart:5:7 - unused_field
   info - This class (or a class which this class inherits from) is marked as '@immutable', but one or more of its instance fields are not final: AuthenticatorElement._authenticators, AuthenticatorElement._index - lib\elements\AuthenticatorElement.dart:8:7 -
          must_be_immutable
   info - This class (or a class which this class inherits from) is marked as '@immutable', but one or more of its instance fields are not final: AuthenticatorList._authenticators - lib\elements\AuthenticatorList.dart:4:7 - must_be_immutable
   info - This class (or a class which this class inherits from) is marked as '@immutable', but one or more of its instance fields are not final: NavBarElement._currentPage - lib\elements\NavBarElement.dart:3:7 - must_be_immutable
   info - This class (or a class which this class inherits from) is marked as '@immutable', but one or more of its instance fields are not final: AccountPage._storage, AccountPage._authenticatorsController - lib\pages\AccountPage.dart:8:7 - must_be_immutable
   info - This class (or a class which this class inherits from) is marked as '@immutable', but one or more of its instance fields are not final: CreateAuthenticatorPage._secret, CreateAuthenticatorPage._nameController, CreateAuthenticatorPage._secretController,
          CreateAuthenticatorPage._digitsController, CreateAuthenticatorPage._periodController - lib\pages\CreateAuthenticatorPage.dart:6:7 - must_be_immutable

7 issues found. (ran in 4.7s)

[√] Flutter (Channel stable, v1.7.8+hotfix.3, on Microsoft Windows [Version 10.0.17763.615], locale en-US)
    • Flutter version 1.7.8+hotfix.3 at D:\ProgramStorage\Applications\Flutter
    • Framework revision b712a172f9 (10 days ago), 2019-07-09 13:14:38 -0700
    • Engine revision 54ad777fd2
    • Dart version 2.4.0

[√] Android toolchain - develop for Android devices (Android SDK version 29.0.1)
    • Android SDK at C:\Users\liamr\AppData\Local\Android\sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-29, build-tools 29.0.1
    • Java binary at: C:\Users\liamr\AppData\Local\JetBrains\Toolbox\apps\AndroidStudio\ch-0\183.5692245\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)
    • All Android licenses accepted.

[√] Android Studio (version 3.4)
    • Android Studio at C:\Users\liamr\AppData\Local\JetBrains\Toolbox\apps\AndroidStudio\ch-0\183.5692245
    • Flutter plugin version 37.1.1
    • Dart plugin version 183.6270
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)

[!] IntelliJ IDEA Ultimate Edition (version 2019.1)
    • IntelliJ at C:\Users\liamr\AppData\Local\JetBrains\Toolbox\apps\IDEA-U\ch-0\191.7479.19
    X Flutter plugin not installed; this adds Flutter specific functionality.
    X Dart plugin not installed; this adds Dart specific functionality.
    • For information about installing plugins, see
      https://flutter.dev/intellij-setup/#installing-the-plugins

[!] Connected device
    ! No devices available

! Doctor found issues in 2 categories.

Please note that the variables given to it are correct (checked many times)

[natebosch]

jsonDecode lives in the SDK and has not been causing problems for us.

If you are still having trouble with this please add a minimal reproducible example and I can take a look.