From 19a761a12cb15d16a2b8bb116ca0dbc533b52394 Mon Sep 17 00:00:00 2001
From: Michael Rittmeister <michael@rittmeister.in>
Date: Mon, 21 Aug 2023 15:45:22 +0200
Subject: [PATCH 1/2] Use contracts for isPresent

---
 .../arbjerg/lavalink/protocol/v4/omissible.kt  | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt b/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt
index f3215cdcd..406392a3e 100644
--- a/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt
+++ b/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt
@@ -6,6 +6,8 @@ import kotlinx.serialization.SerializationException
 import kotlinx.serialization.descriptors.SerialDescriptor
 import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
+import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.contract
 import kotlin.jvm.JvmInline
 
 @Serializable(with = OmissableSerializer::class)
@@ -70,9 +72,21 @@ class OmissableSerializer<T>(private val childSerializer: KSerializer<T>) : KSer
     }
 }
 
-fun <T : Any> Omissible<T>.isPresent() = this is Omissible.Present
+@OptIn(ExperimentalContracts::class)
+fun <T : Any> Omissible<T>.isPresent(): Boolean {
+    contract {
+        returns(true) implies (this@isPresent is Omissible.Present<T>)
+    }
+    return this is Omissible.Present
+}
 
-fun <T : Any> Omissible<T>.isOmitted() = this is Omissible.Omitted
+@OptIn(ExperimentalContracts::class)
+fun <T : Any> Omissible<T>.isOmitted(): Boolean {
+    contract {
+        returns(true) implies (this@isOmitted is Omissible.Present<T>)
+    }
+    return this is Omissible.Omitted
+}
 
 fun <T : Any?> Omissible<T>.takeIfPresent(predicate: (T) -> Boolean = { true }) =
     if (this is Omissible.Present) value.takeIf(predicate) else null

From 26461e8305d11154c65896b02e923449fca607de Mon Sep 17 00:00:00 2001
From: Michael Rittmeister <michael@rittmeister.in>
Date: Mon, 21 Aug 2023 15:48:21 +0200
Subject: [PATCH 2/2] Fix isOmitted

---
 .../kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt        | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt b/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt
index 406392a3e..a9fbb1aaf 100644
--- a/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt
+++ b/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt
@@ -83,7 +83,7 @@ fun <T : Any> Omissible<T>.isPresent(): Boolean {
 @OptIn(ExperimentalContracts::class)
 fun <T : Any> Omissible<T>.isOmitted(): Boolean {
     contract {
-        returns(true) implies (this@isOmitted is Omissible.Present<T>)
+        returns(true) implies (this@isOmitted is Omissible.Omitted<T>)
     }
     return this is Omissible.Omitted
 }