dot net core 3.1 The type or namespace name 'TestClassAttribute' could not be found (are you missing a using directive or an assembly reference?)
snippet in assembly

dot net core 3.1 The type or namespace name 'TestClassAttribute' could not be found (are you missing a using directive or an assembly reference?)

user7620

1. Close Visual Studio
2. Delete .vs folder
3. Reopen Visual Studio and it should work.