Advance deprecation level of Experimental and UseExperimental annotations to ERROR

libraries/stdlib/src/kotlin/annotations/Experimental.kt

@@ -25,6 +25,7 @@ import kotlin.reflect.KClass
 @Retention(BINARY)
 @SinceKotlin("1.2")
 @RequireKotlin("1.2.50", versionKind = RequireKotlinVersionKind.COMPILER_VERSION)
+@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.6")
 @Deprecated("Please use RequiresOptIn instead.")
 public annotation class Experimental(val level: Level = Level.ERROR) {
     /**
@@ -51,6 +52,7 @@ public annotation class Experimental(val level: Level = Level.ERROR) {
 @Retention(SOURCE)
 @SinceKotlin("1.2")
 @RequireKotlin("1.2.50", versionKind = RequireKotlinVersionKind.COMPILER_VERSION)
+@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.6")
 @Deprecated("Please use OptIn instead.", ReplaceWith("OptIn(*markerClass)", "kotlin.OptIn"))
 public annotation class UseExperimental(
     vararg val markerClass: KClass<out Annotation>

libraries/stdlib/src/kotlin/annotations/ExperimentalStdlibApi.kt

@@ -14,8 +14,6 @@ import kotlin.annotation.AnnotationTarget.*
  * annotating that usage with the [OptIn] annotation, e.g. `@OptIn(ExperimentalStdlibApi::class)`,
  * or by using the compiler argument `-opt-in=kotlin.ExperimentalStdlibApi`.
  */
-@Suppress("DEPRECATION")
-@Experimental(level = Experimental.Level.ERROR)
 @RequiresOptIn(level = RequiresOptIn.Level.ERROR)
 @Retention(AnnotationRetention.BINARY)
 @Target(

libraries/stdlib/src/kotlin/annotations/Multiplatform.kt

@@ -16,8 +16,6 @@ import kotlin.internal.RequireKotlinVersionKind
  * annotating that usage with the [OptIn] annotation, e.g. `@OptIn(ExperimentalMultiplatform::class)`,
  * or by using the compiler argument `-opt-in=kotlin.ExperimentalMultiplatform`.
  */
-@Suppress("DEPRECATION")
-@Experimental
 @RequiresOptIn
 @MustBeDocumented
 @Target(

libraries/stdlib/src/kotlin/contracts/ContractBuilder.kt

@@ -16,10 +16,8 @@ import kotlin.internal.InlineOnly
  * annotating that usage with the [OptIn] annotation, e.g. `@OptIn(ExperimentalContracts::class)`,
  * or by using the compiler argument `-opt-in=kotlin.contracts.ExperimentalContracts`.
  */
-@Suppress("DEPRECATION")
 @Retention(AnnotationRetention.BINARY)
 @SinceKotlin("1.3")
-@Experimental
 @RequiresOptIn
 @MustBeDocumented
 public annotation class ExperimentalContracts

libraries/stdlib/src/kotlin/experimental/inferenceMarker.kt

@@ -12,8 +12,6 @@ package kotlin.experimental
  * annotating that usage with the [OptIn] annotation, e.g. `@OptIn(ExperimentalTypeInference::class)`,
  * or by using the compiler argument `-opt-in=kotlin.experimental.ExperimentalTypeInference`.
  */
-@Suppress("DEPRECATION")
-@Experimental(level = Experimental.Level.ERROR)
 @RequiresOptIn(level = RequiresOptIn.Level.ERROR)
 @MustBeDocumented
 @Retention(AnnotationRetention.BINARY)

libraries/stdlib/src/kotlin/time/ExperimentalTime.kt

@@ -18,8 +18,6 @@ import kotlin.annotation.AnnotationTarget.*
  * annotating that usage with the [OptIn] annotation, e.g. `@OptIn(ExperimentalTime::class)`,
  * or by using the compiler argument `-opt-in=kotlin.time.ExperimentalTime`.
  */
-@Suppress("DEPRECATION")
-@Experimental(level = Experimental.Level.ERROR)
 @RequiresOptIn(level = RequiresOptIn.Level.ERROR)
 @MustBeDocumented
 @Retention(AnnotationRetention.BINARY)