Surprised error while building apps "Couldn't find outer class" after update to gradle3.1.0-beta1(Android Studio 3.1 Beta1)

Question

run: ./gradlew clean assembleDebug

Exception in thread "main" java.lang.NullPointerException: Couldn't find outer class xxxxx/SomeClass$someMethod$1$1$2 of xxxx/SomeClass$someMethod$1$1$2$1

execution failed for task ':app:transformClassesWithDesugarForDevDebug'.

issue

Same problem https://www.reddit.com/r/androiddev/comments/7u8tug/android_studio_31_beta_1_is_available/

Answer 1

workaround solved: https://issuetracker.google.com/issues/72750890#comment10

a bug is also filled at JB.