Unable to build iOS or Android app after upgrade to Flutter 3.0

Question

After upgrading to Flutter 3.0 I am no longer able to build any of my apps for either iOS or Android and get the same errors in both builds:

: Error: Member not found: 'UnicodeChar'.
  int get UnicodeChar => Char.UnicodeChar;
                              ^^^^^^^^^^^
: Error: Setter not found: 'UnicodeChar'.
  set UnicodeChar(int value) => Char.UnicodeChar = value;

                                     ^^^^^^^^^^^
: Error: Member not found: 'AsciiChar'.
  int get AsciiChar => Char.AsciiChar;
                            ^^^^^^^^^
: Error: Setter not found: 'AsciiChar'.
  set AsciiChar(int value) => Char.AsciiChar = value;

                                   ^^^^^^^^^

and these errors are in the file "src/structs.g.dart" (part of Flutter/Dart as far as I can tell) as follows:

/// {@category Struct}
class _CHAR_INFO__Char_e__Union extends Union {
  @Uint16()
  external int UnicodeChar;
  @Uint8()
  external int AsciiChar;
}

extension CHAR_INFO_Extension on CHAR_INFO {
  int get UnicodeChar => Char.UnicodeChar;
  set UnicodeChar(int value) => Char.UnicodeChar = value;

  int get AsciiChar => Char.AsciiChar;
  set AsciiChar(int value) => Char.AsciiChar = value;
}

I am running VSCode 1.67.1 on macOS Monterey 12.3.1 and flutter doctor -v shows no errors found.

It appears that the file "src/structs.g.dart" seems to be part of the Win32 components in "pub.dartlang.org" but I am not building my apps for Windows (yet).

Any ideas on what I need to do to be able to build for iOS and Android again will be much appreciated.

Thanks

Les

Solution

So, something which helped me:

1. remove the next folder /Users/your-user/.pub-cache/hosted/pub.dartlang.org
2. hit flutter pub upgrade

and then try to run your project 🎉

Comments

[Les]

I deleted the build folder and ran flutter clean but it made no difference (I am still getting the same errors)...

[Ermindo Lopes]

same here.. errors persist... and Flutter doctor show Visual Studio Error - Exception: Bad UTF-8 encoding (U+FFFD; REPLACEMENT CHARACTER) found while decoding string

[Les]

Hi Andriy, On its own that did not work but after then running flutter pub upgrade it is now all good. Many thanks.

[Andriy Antonov]

Awesome :) glad to help. please if you don't mind - accept the answer

[Hoàng Anh Chung]

Flow step below :