Remove some @Suppress that are no longer necessary

core/commonMain/src/kotlinx/serialization/builtins/BuiltinSerializers.kt

@@ -61,7 +61,6 @@ public fun Char.Companion.serializer(): KSerializer<Char> = CharSerializer
  * Returns serializer for [CharArray] with [descriptor][SerialDescriptor] of [StructureKind.LIST] kind.
  * Each element of the array is serialized one by one with [Char.Companion.serializer].
  */
-@Suppress("UNCHECKED_CAST")
 public fun CharArraySerializer(): KSerializer<CharArray> = CharArraySerializer
 
 /**

core/commonTest/src/kotlinx/serialization/BasicTypesSerializationTest.kt

@@ -198,7 +198,6 @@ class BasicTypesSerializationTest {
         // impossible to deserialize Nothing
         assertFailsWith(SerializationException::class, "'kotlin.Nothing' does not have instances") {
             val inp = KeyValueInput(Parser(StringReader("42")))
-            @Suppress("IMPLICIT_NOTHING_TYPE_ARGUMENT_IN_RETURN_POSITION")
             inp.decodeSerializableValue(NothingSerializer())
         }
 

formats/json-tests/commonTest/src/kotlinx/serialization/features/inline/InlineClassesCompleteTest.kt

@@ -1,8 +1,6 @@
 /*
  * Copyright 2017-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
-@file:Suppress("INLINE_CLASSES_NOT_SUPPORTED", "SERIALIZER_NOT_FOUND")
-
 package kotlinx.serialization.features.inline
 
 import kotlinx.serialization.*

formats/json-tests/commonTest/src/kotlinx/serialization/features/inline/InlineClassesTest.kt

@@ -2,8 +2,6 @@
  * Copyright 2017-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
 
-@file:Suppress("INLINE_CLASSES_NOT_SUPPORTED", "SERIALIZER_NOT_FOUND")
-
 package kotlinx.serialization.features.inline
 
 import kotlinx.serialization.*

formats/json-tests/commonTest/src/kotlinx/serialization/test/TestHelpers.kt

@@ -2,8 +2,6 @@
  * Copyright 2017-2022 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
 
-@file:Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
-
 package kotlinx.serialization.test
 
 import kotlinx.serialization.*

formats/json-tests/jvmTest/src/kotlinx/serialization/features/JsonJvmStreamsTest.kt

@@ -2,14 +2,11 @@
  * Copyright 2017-2022 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
 
-@file:Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
-
 package kotlinx.serialization.features
 
 import kotlinx.serialization.*
 import kotlinx.serialization.builtins.serializer
 import kotlinx.serialization.json.*
-import kotlinx.serialization.json.internal.BATCH_SIZE
 import kotlinx.serialization.modules.*
 import kotlinx.serialization.test.*
 import org.junit.Test
@@ -19,6 +16,7 @@ import kotlin.test.assertEquals
 import kotlin.test.assertFailsWith
 
 class JsonJvmStreamsTest {
+    val BATCH_SIZE = 16 * 1024 // kotlinx.serialization.json.internal.BATCH_SIZE
     private val strLen = BATCH_SIZE * 2 + 42
 
     @Test

formats/json/commonMain/src/kotlinx/serialization/json/internal/StringOps.kt

@@ -12,8 +12,8 @@ private fun toHexChar(i: Int) : Char {
     else (d - 10 + 'a'.code).toChar()
 }
 
-@PublishedApi
-internal val ESCAPE_STRINGS: Array<String?> = arrayOfNulls<String>(93).apply {
+@JsonFriendModuleApi
+public val ESCAPE_STRINGS: Array<String?> = arrayOfNulls<String>(93).apply {
     for (c in 0..0x1f) {
         val c1 = toHexChar(c shr 12)
         val c2 = toHexChar(c shr 8)

formats/json/commonMain/src/kotlinx/serialization/json/internal/TreeJsonDecoder.kt

@@ -203,7 +203,6 @@ private open class JsonTreeDecoder(
             { (currentElement(tag) as? JsonPrimitive)?.contentOrNull }
         )
 
-    @Suppress("INVISIBLE_MEMBER")
     override fun decodeElementIndex(descriptor: SerialDescriptor): Int {
         while (position < descriptor.elementsCount) {
             val name = descriptor.getTag(position++)