I have a Kotlin enum class. When I compile the release package, Redex warns me about a type mismatch issue. Its definition is as follows:

open class Config private constructor(val adapterType: AdapterType){
    enum class AdapterType {
        COMMON,
        GLOBAL,
    }
}

The Redex error is as Inconsistency found in Dex code for LX/1B3;.values$54379476:()[I, Lcom/model/Config$AdapterType;.values$54379476:()[I OK1. Type error in method Lcom/model/Config$AdapterType;.values$54379476:()[I at instruction 'INVOKE_VIRTUAL v0, [Ljava/lang/Object;.clone:()Ljava/lang/Object;' @ 0x7fe694164360 for : [I is not assignable to [Ljava/lang/Object;

I used Smali to check the classes.dex and found that this class was not correctly unboxed. The decompiled result is as follows:

# static fields
.field public static final COMMON$4f1f5ff0:I = 0x1

.field public static final GLOBAL$4f1f5ff0:I = 0x2

.field private static final synthetic L:[I


# direct methods
.method static constructor <clinit>()V
    .registers 4

    const/4 v0, 0x2

    new-array v1, v0, [I

    const/4 v2, 0x0

    const/4 v3, 0x1

    aput v3, v1, v2

    aput v0, v1, v3

    .line 35
    sput-object v1, Lcom/a/a$a;->L:[I

    return-void
.end method

.method public static values$54379476()[I
    .registers 1

    sget-object v0, Lcom/a/a$a;->L:[I

    invoke-virtual {v0}, [Ljava/lang/Object;->clone()Ljava/lang/Object;

    move-result-object v0

    check-cast v0, [I

    return-object v0
.end method

I see that the reason is Proguard does not replace the clone() to [I;->clone()Ljava/lang/Object; after unboxing the enum type with I, which led to the type mismatch error. However, this is the only enum in my entire package that triggered this error. I haven’t explicitly called the clone() or values() methods of this enum.

I resolved the issue by keeping this enum,

-keep enum com.model.Config$AdapterType {
*;
}

but I would like to know why this error occurred ?