Flutter/Dart Error: A function body must be provided. Try adding a function body.

(Illustration: Formosan Blue Magpie, which is a endemic species in Taiwan, flapping its wings. Image source: Wikipedia。)

A quick memo about an error message I encountered during the development works using Flutter: A function body must be provided. Try adding a function body.

When I got the error message, my development environment is following: Android Studio 3.6.3 with Flutter Plugin 45.1.1.

After stuck, nothing can be done. The code can be executed smoothly at the previous moment, and it is stuck without modification. It is useless to restart Android Studio. Unfortunately, no screenshots were left on the day, only keywords were left for reference.

The solution I found:

• Clean up: ~/.dartServer/.analysis-driver/

Reference:

• https://github.com/flutter/flutter/issues/24279