Support situation when argument for serializer<T>() function has SerialInfo annotations.

Because SerializationJvmIrIntrinsicSupport does not instantiate annotations yet,
this info could be lost. As a workaround, it is possible to call Companion.serializer()
functions instead of direct serializer instantiation, as they are plugin-generated
and correctly handle annotations.

Note that for some cases (enums & interfaces) this WA is not enough, so additional work
is needed later.

Fixes https://github.com/Kotlin/kotlinx.serialization/issues/2179

plugins/kotlinx-serialization/testData/boxIr/intrinsicAnnotations.kt

@@ -0,0 +1,40 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+// TARGET_BACKEND: JVM_IR
+
+// WITH_STDLIB
+
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+import kotlinx.serialization.internal.*
+import kotlinx.serialization.descriptors.*
+import kotlinx.serialization.modules.*
+import kotlin.test.*
+
+@Serializable
+@JsonClassDiscriminator("sealed")
+sealed class Sealed
+
+@Serializable
+@JsonClassDiscriminator("abstract")
+abstract class Abstract
+
+@Serializable
+@JsonClassDiscriminator("object")
+object Object
+
+fun test(descriptor: SerialDescriptor, value: String, name: String = descriptor.serialName) {
+    val anno = descriptor.annotations.filterIsInstance<JsonClassDiscriminator>().singleOrNull()
+    requireNotNull(anno) { "Annotation value not found for $name" }
+    assertEquals(anno.discriminator, value, "Annotation value incorrect for $name")
+}
+
+fun box(): String {
+    test(serializer<Sealed>().descriptor, "sealed")
+    test(serializer<Abstract>().descriptor, "abstract")
+    test(serializer<Object>().descriptor, "object")
+    test(serializer<List<Sealed>>().descriptor.getElementDescriptor(0), "sealed", "List<Sealed>")
+    test(serializer<List<Abstract>>().descriptor.getElementDescriptor(0), "abstract", "List<Abstract>")
+    test(serializer<List<Object>>().descriptor.getElementDescriptor(0), "object", "List<Object>")
+    test(serializer<Array<Sealed>>().descriptor.getElementDescriptor(0), "sealed", "Array<Sealed>")
+    return "OK"
+}

plugins/kotlinx-serialization/testData/codegen/Intrinsics.asm.ir.txt

@@ -127,7 +127,8 @@ public final class IntrinsicsKt : java/lang/Object {
           GETSTATIC (Box, Companion, LBox$Companion;)
           NEW (kotlinx/serialization/internal/ArrayListSerializer)
           DUP
-          GETSTATIC (Simple$$serializer, INSTANCE, LSimple$$serializer;)
+          GETSTATIC (Simple, Companion, LSimple$Companion;)
+          INVOKEVIRTUAL (Simple$Companion, serializer, ()Lkotlinx/serialization/KSerializer;)
           INVOKESPECIAL (kotlinx/serialization/internal/ArrayListSerializer, <init>, (Lkotlinx/serialization/KSerializer;)V)
           INVOKEVIRTUAL (Box$Companion, serializer, (Lkotlinx/serialization/KSerializer;)Lkotlinx/serialization/KSerializer;)
           POP
@@ -142,7 +143,8 @@ public final class IntrinsicsKt : java/lang/Object {
           GETSTATIC (Box, Companion, LBox$Companion;)
           NEW (kotlinx/serialization/internal/ArrayListSerializer)
           DUP
-          GETSTATIC (Simple$$serializer, INSTANCE, LSimple$$serializer;)
+          GETSTATIC (Simple, Companion, LSimple$Companion;)
+          INVOKEVIRTUAL (Simple$Companion, serializer, ()Lkotlinx/serialization/KSerializer;)
           INVOKESPECIAL (kotlinx/serialization/internal/ArrayListSerializer, <init>, (Lkotlinx/serialization/KSerializer;)V)
           INVOKEVIRTUAL (Box$Companion, serializer, (Lkotlinx/serialization/KSerializer;)Lkotlinx/serialization/KSerializer;)
           INVOKESPECIAL (kotlinx/serialization/internal/ArrayListSerializer, <init>, (Lkotlinx/serialization/KSerializer;)V)
@@ -167,10 +169,9 @@ public final class IntrinsicsKt : java/lang/Object {
           DUP
           NEW (kotlinx/serialization/internal/ArrayListSerializer)
           DUP
-          NEW (Box$$serializer)
-          DUP
+          GETSTATIC (Box, Companion, LBox$Companion;)
           GETSTATIC (kotlinx/serialization/internal/IntSerializer, INSTANCE, Lkotlinx/serialization/internal/IntSerializer;)
-          INVOKESPECIAL (Box$$serializer, <init>, (Lkotlinx/serialization/KSerializer;)V)
+          INVOKEVIRTUAL (Box$Companion, serializer, (Lkotlinx/serialization/KSerializer;)Lkotlinx/serialization/KSerializer;)
           INVOKESPECIAL (kotlinx/serialization/internal/ArrayListSerializer, <init>, (Lkotlinx/serialization/KSerializer;)V)
           INVOKESPECIAL (kotlinx/serialization/internal/ArrayListSerializer, <init>, (Lkotlinx/serialization/KSerializer;)V)
         LABEL (L21)

plugins/kotlinx-serialization/testData/codegen/IntrinsicsAdvanced.asm.ir.txt

@@ -50,7 +50,8 @@ public final class IntrinsicsAdvancedKt : java/lang/Object {
           POP
           NEW (kotlinx/serialization/internal/ArrayListSerializer)
           DUP
-          GETSTATIC (Simple$$serializer, INSTANCE, LSimple$$serializer;)
+          GETSTATIC (Simple, Companion, LSimple$Companion;)
+          INVOKEVIRTUAL (Simple$Companion, serializer, ()Lkotlinx/serialization/KSerializer;)
           INVOKESPECIAL (kotlinx/serialization/internal/ArrayListSerializer, <init>, (Lkotlinx/serialization/KSerializer;)V)
           POP
         LABEL (L3)
@@ -109,7 +110,8 @@ public final class IntrinsicsAdvancedKt : java/lang/Object {
           ANEWARRAY (kotlinx/serialization/KSerializer)
           DUP
           ICONST_0
-          GETSTATIC (Simple$$serializer, INSTANCE, LSimple$$serializer;)
+          GETSTATIC (Simple, Companion, LSimple$Companion;)
+          INVOKEVIRTUAL (Simple$Companion, serializer, ()Lkotlinx/serialization/KSerializer;)
           AASTORE
           INVOKESTATIC (kotlinx/serialization/SerializersKt, noCompiledSerializer, (Lkotlinx/serialization/modules/SerializersModule;Lkotlin/reflect/KClass;[Lkotlinx/serialization/KSerializer;)Lkotlinx/serialization/KSerializer;)
         LABEL (L15)