Android studio warning - InnerClass annotations are missing corresponding EnclosingMember annotations

Question

I recently upgraded to Android Studio 3.1 and upon building my Kotlin with Java project I got the following warning.

InnerClass annotations are missing c

Answer 1

It may because some annotations be confused, so just add proguard rule:

-keepattributes *Annotation*
-keep @**annotation** class * {*;}

it worked fine to me.