fix: handle Kotlin 1.9+ $ENTRIES pattern in enum restoration

[clawdbot-silly-waddle]

NOTE: This is what one may call "AI slop". Feel free to close this PR if it's not up to your quality standards or even if you just aren't interested in reviewing it. I use these changes downstream on an APK and thought I might as well make a PR offering to upstream them, as your CONTRIBUTING.md doesn't say anything discouraging this.

Kotlin 1.9+ compiles enums with an additional $ENTRIES field initialized from the $VALUES array via EnumEntriesKt.enumEntries(). EnumVisitor did not recognize this pattern, causing enum restoration to fail for most Kotlin 1.9+ enum classes.

The fix handles three cases:

• RegisterArg in convertToEnum(): when CodeShrinkVisitor cannot inline the filled-array instruction (2 uses), the assign instruction is reached via RegisterArg instead of InsnWrapArg
• removeEntriesFieldInit(): cleans up the $ENTRIES SPUT, handling both the wrapped case (INVOKE inlined into SPUT by CodeShrinkVisitor) and the standalone case
• NPE in checkExternalRegUsage(): InsnArg.unwrap() returns null for RegisterArg, causing NPE when checking FILLED_NEW_ARRAY external uses

Includes a smali test compiled from a real Kotlin 2.3 enum.

Tested on Tumblr v43.4.0.107 (com.tumblr, 22,124 classes):

• "Failed to restore enum class" warnings: 363 -> 56 (-84.6%)
• "Unknown enum class pattern" warnings: 330 -> 15 (-95.5%)
• Total enum-related warnings: 693 -> 71 (-89.8%)

[clawdbot-silly-waddle]

The smali test file was generated from the following Kotlin source using kotlinc 2.3.10:

package enums

enum class TestEnumKotlinEntries {
    ALPHA,
    BETA,
    GAMMA
}

Compiled with kotlinc TestEnumKotlinEntries.kt -d out/, then converted to dex with d8 and disassembled with baksmali. Class name adjusted to match the test package.

[skylot]

Thanks, code looks good and succesfully restores enum, but it keeps getEntries() method which uses removed $ENTRIES field:

public enum TestEnumKotlinEntries {
    ALPHA,
    BETA,
    GAMMA;

    public static EnumEntries<TestEnumKotlinEntries> getEntries() {
        return $ENTRIES;
    }
}

And it is better to generate compilable code, so I fix this PR to keep $ENTRIES field and use values() method instead synthetic $values(). Result is correct java code:

public enum TestEnumKotlinEntries {
    ALPHA,
    BETA,
    GAMMA;

    private static final /* synthetic */ EnumEntries $ENTRIES = EnumEntriesKt.enumEntries(values());

    public static EnumEntries<TestEnumKotlinEntries> getEntries() {
        return $ENTRIES;
    }
}