Annotate contract DSL with @SinceKotlin

libraries/stdlib/src/kotlin/internal/Annotations.kt

@@ -116,4 +116,5 @@ internal enum class RequireKotlinVersionKind {
  * Specifies that this declaration is a part of special DSL, used for constructing function's contract.
  */
 @Retention(AnnotationRetention.BINARY)
+@SinceKotlin("1.2")
 internal annotation class ContractsDsl

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

@@ -20,6 +20,7 @@ import kotlin.internal.ContractsDsl
 import kotlin.internal.InlineOnly
 
 @ContractsDsl
+@SinceKotlin("1.2")
 internal interface ContractBuilder {
     @ContractsDsl fun returns(): Returns
     @ContractsDsl fun returns(value: Any?): Returns
@@ -28,6 +29,7 @@ internal interface ContractBuilder {
 }
 
 @ContractsDsl
+@SinceKotlin("1.2")
 internal enum class InvocationKind {
     @ContractsDsl AT_MOST_ONCE,
     @ContractsDsl AT_LEAST_ONCE,
@@ -37,4 +39,5 @@ internal enum class InvocationKind {
 
 @ContractsDsl
 @InlineOnly
+@SinceKotlin("1.2")
 internal inline fun contract(builder: ContractBuilder.() -> Unit) { }

libraries/stdlib/src/kotlin/internal/contracts/Effect.kt

@@ -19,12 +19,15 @@ package kotlin.internal.contracts
 import kotlin.internal.ContractsDsl
 
 @ContractsDsl
+@SinceKotlin("1.2")
 internal interface Effect
 
 @ContractsDsl
+@SinceKotlin("1.2")
 internal interface ConditionalEffect : Effect
 
 @ContractsDsl
+@SinceKotlin("1.2")
 internal interface SimpleEffect {
     @ContractsDsl
     infix fun implies(booleanExpression: Boolean): ConditionalEffect
@@ -32,10 +35,13 @@ internal interface SimpleEffect {
 
 
 @ContractsDsl
+@SinceKotlin("1.2")
 internal interface Returns : SimpleEffect
 
 @ContractsDsl
+@SinceKotlin("1.2")
 internal interface ReturnsNotNull : SimpleEffect
 
 @ContractsDsl
+@SinceKotlin("1.2")
 internal interface CallsInPlace : SimpleEffect