ProGuard issues with Android Archieve(.aar) library

Question

I've a library project which I want to distribute, in AAR format. I've applied ProGuard on it.

ProGuard settings works well if I use this lib as a module, but not when I use resulting AAR. Basically it fails with exception "java.lang.IllegalArgumentException: already added Lmy/lib/package/name/R;" in Application project.

ProGuard is renaming one of my lib class to R, and I feel which is causing problem in Application project as R is used for Resources.

How do I specify proguard mapping in Studio to tell it not to rename to R.

Update: after adding AAR file as a new module, am getting this error:

UNEXPECTED TOP-LEVEL EXCEPTION:
com.android.dex.DexException: Multiple dex files define Lmy/lib/package/name/R;
    at com.android.dx.merge.DexMerger.readSortableTypes(DexMerger.java:596)
    at com.android.dx.merge.DexMerger.getSortedTypes(DexMerger.java:554)
    at com.android.dx.merge.DexMerger.mergeClassDefs(DexMerger.java:535)
    at com.android.dx.merge.DexMerger.mergeDexes(DexMerger.java:171)
    at com.android.dx.merge.DexMerger.merge(DexMerger.java:189)
    at com.android.dx.command.dexer.Main.mergeLibraryDexBuffers(Main.java:454)
    at com.android.dx.command.dexer.Main.runMonoDex(Main.java:303)
    at com.android.dx.command.dexer.Main.run(Main.java:246)
    at com.android.dx.command.dexer.Main.main(Main.java:215)
    at com.android.dx.command.Main.main(Main.java:106)

Answer 1

Okay then, answering myself.

Tried running ProGuard manually on .aar, worked with latest version v5.2.1. Didn't work with default version v4.7 which came with Studio v1.2.2. Hope this helps.