Bad state: Unexpected diagnostics: after flutter upgrade to 1.20.1

Question

What is the issue?

xxx@xxx-Inspiron-14-3467:~/xxx$ flutter pub run build_runner build[INFO] Generating build script...
[INFO] Generating build script complete         


        

Answer 1

try it:

1- flutter clean

2- go on dev channel: flutter channel dev

3- upgrade: flutter upgrade --force

4- flutter pub get

5- try to build

6- back on stable or master channel: flutter channel stable (flutter channel master)

7- upgrade: flutter upgrade --force