尝试安装Firebase后Flutter新项目及旧项目均无法编译运行

报错信息 #

Unhandled exception:
Crash when compiling file:///Users/Documents/FlutterDevelopment/SDKS/flutter/packages/flutter/lib/src/widgets/app.dart at character offset 71686:
../…/widgets/app.dart:1
type 'Null' is not a subtype of type 'Procedure' in type cast

解决步骤 #

• 清理项目缓存并重新拉取依赖

  flutter clean
  flutter pub get
  

• 切换Flutter至稳定版并更新SDK

  flutter channel stable
  flutter upgrade
  

• 删除项目根目录下的.dart_tool、build文件夹后，重新尝试编译
• 清除Firebase集成残留：移除项目中的google-services.json（Android）/GoogleService-Info.plist（iOS）文件，删除pubspec.yaml内的Firebase相关依赖，再执行flutter pub get
• 重置VSCode Flutter插件：禁用后重新启用，或直接重启VSCode

内容的提问来源于stack exchange，提问作者user21233522