In general lambdas should be translated to a new class extending from

Lambda

and

FunctionN

. So one of my lambdas gets translated to this:

new Lambda(success)
{
    public final void invoke()
    {        MyAccessory.access$getModule$p(this.this$0).disconnect(success, failure);
    }
}

With details depending on the exact input arguments and captured variables for the specific lambda. But ProGuard mangles it to this:

static final class e
            extends Lambda
            implements Function1<MyError, Unit>
{
    e(MyAccessory myAccessory, Function0 paramFunction0, Function1 paramFunction1)
    {
        super();
    }
}

Note that the invoke method is missing entirely.

If I add both

-dontshrink

and

-dontobfuscate

to the rules the first version is generated and the code will work. If I disable either the second version is generated and the code fails. Since I do want to obfuscate the code I'm looking for more specific rules to keep the lambdas intact. I'm trying rules like these but they don't seem to have any effect:

-keep class kotlin.jvm.internal.Lambda { *; }
-keep class * extends kotlin.jvm.internal.Lambda { *; }
-keep class kotlin.coroutines.jvm.internal.SuspendLambda { *; }
-keep class * extends kotlin.coroutines.jvm.internal.SuspendLambda { *; }

-keepclassmembers class * extends kotlin.jvm.internal.Lambda {
    *;
}
-keepclassmembers class * extends kotlin.coroutines.jvm.internal.SuspendLambda {
    *;
}
-keepclassmembers class kotlin.jvm.internal.Lambda {
    *;
}
-keepclassmembers class kotlin.coroutines.jvm.internal.SuspendLambda {
    *;
}

This is for a jvm library project where I'm applying ProGuard (v6.0.3) manually. So it's not directly related to Android but I figured there is a good chance someone here knows more about ProGuard than I do.