title: Flutter 2: problem in Intl null safety library
body: <p>I upgrade my flutter sdk to flutter 2.0.0. After updating sdk I have changed almost all libraries to null safety version:</p>
  <pre><code>environment:
    sdk: '&gt;=2.12.0 &lt;3.0.0'
  
  dependencies:
    flutter:
      sdk: flutter
    flutter_localizations:
      sdk: flutter 
    cupertino_icons: ^0.1.3
    encrypt: ^4.1.0
    flutter_hooks: ^0.15.0
    flutter_map: ^0.11.0
    flutter_password_strength: ^0.1.5
    flutter_svg: ^0.18.0
    geolocator: ^7.0.1
    get: ^3.25.6
    get_it: ^6.0.0
    injectable: ^1.1.2
    local_auth: ^1.1.0
    moor_flutter: ^3.1.0
    provider: ^5.0.0
    shared_preferences: ^2.0.3
    supercharged: ^1.12.0
    intl: ^0.17.0
  </code></pre>
  <p>after updating I run dart <code>$ dart migrate</code> command. But It shows these problem about intl plugin:</p>
  <pre><code>Analyzing project...
  [---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------/]
  5 analysis issues found:
    error • A value of type 'Null' can't be returned from the function '_findExact' because it has a return type of 'MessageLookupByLibrary' at lib/generated/intl/messages_all.dart:34:14 • (return_of_invalid_type)
    error • A value of type 'Null' can't be returned from the function '_findGeneratedMessagesFor' because it has a return type of 'MessageLookupByLibrary' at lib/generated/intl/messages_all.dart:65:36 • (return_of_invalid_type)
    error • Non-nullable instance field 'current' must be initialized at lib/generated/l10n.dart:16:3 • (not_initialized_non_nullable_instance_field)
    error • The non-nullable variable 'current' must be initialized at lib/generated/l10n.dart:18:12 • (not_initialized_non_nullable_variable)
    error • A value of type 'S?' can't be returned from the method 'of' because it has a return type of 'S' at lib/generated/l10n.dart:35:12 • (return_of_invalid_type)
  
  The migration tool didn't start, due to analysis errors.
  </code></pre>
  <p><a href="https://i.stack.imgur.com/jBorw.png" rel="noreferrer"><img src="https://i.stack.imgur.com/jBorw.png" alt="enter image description here" /></a></p>
  <p><a href="https://i.stack.imgur.com/O84l5.png" rel="noreferrer"><img src="https://i.stack.imgur.com/O84l5.png" alt="enter image description here" /></a></p>
  <p>I am using last version of intl ? How can I fix that?</p>
  <pre><code>Doctor summary (to see all details, run flutter doctor -v):
  [✓] Flutter (Channel stable, 2.0.0, on Linux, locale en_US.UTF-8)
  [✓] Android toolchain - develop for Android devices (Android SDK version 30.0.0-rc1)
  [✓] Chrome - develop for the web
  [✓] Android Studio (version 4.0)
  [✓] VS Code (version 1.53.2)
  [✓] Connected device (2 available)
  
  • No issues found!
  </code></pre>