Make unsigned types experimental (with warning if not opted-in)

generators/builtins/unsignedTypes.kt

@@ -43,6 +43,7 @@ class UnsignedTypeGenerator(val type: UnsignedType, out: PrintWriter) : BuiltIns
 
         out.println("@Suppress(\"NON_PUBLIC_PRIMARY_CONSTRUCTOR_OF_INLINE_CLASS\")")
         out.println("@SinceKotlin(\"1.3\")")
+        out.println("@ExperimentalUnsignedTypes")
         out.println("public inline class $className internal constructor(private val data: $storageType) : Comparable<$className> {")
         out.println()
         out.println("""    companion object {
@@ -198,6 +199,7 @@ class UnsignedTypeGenerator(val type: UnsignedType, out: PrintWriter) : BuiltIns
             val otherSigned = otherType.asSigned.capitalized
             val thisSigned = type.asSigned.capitalized
             out.println("@SinceKotlin(\"1.3\")")
+            out.println("@ExperimentalUnsignedTypes")
             out.print("public fun $otherSigned.to$className(): $className = ")
             out.println(when {
                 otherType < type -> "$className(this.to$thisSigned() and ${otherType.mask})"
@@ -241,6 +243,7 @@ class UnsignedIteratorsGenerator(out: PrintWriter) : BuiltInsSourceGenerator(out
             val s = type.capitalized
             out.println("/** An iterator over a sequence of values of type `$s`. */")
             out.println("@SinceKotlin(\"1.3\")")
+            out.println("@ExperimentalUnsignedTypes")
             out.println("public abstract class ${s}Iterator : Iterator<$s> {")
             // TODO: Sort modifiers
             out.println("    override final fun next() = next$s()")
@@ -261,6 +264,7 @@ class UnsignedArrayGenerator(val type: UnsignedType, out: PrintWriter) : BuiltIn
     val storageArrayType = storageElementType + "Array"
     override fun generateBody() {
         out.println("@SinceKotlin(\"1.3\")")
+        out.println("@ExperimentalUnsignedTypes")
         out.println("public inline class $arrayType")
         out.println("@Suppress(\"NON_PUBLIC_PRIMARY_CONSTRUCTOR_OF_INLINE_CLASS\")")
         out.println("@PublishedApi")
@@ -299,11 +303,13 @@ class UnsignedArrayGenerator(val type: UnsignedType, out: PrintWriter) : BuiltIn
         // TODO: Make inline constructor, like in ByteArray
         out.println()
         out.println("@SinceKotlin(\"1.3\")")
+        out.println("@ExperimentalUnsignedTypes")
         out.println("""public inline fun $arrayType(size: Int, init: (Int) -> $elementType): $arrayType {
     return $arrayType($storageArrayType(size) { index -> init(index).to$storageElementType() })
 }
 
 @SinceKotlin("1.3")
+@ExperimentalUnsignedTypes
 // TODO: @kotlin.internal.InlineOnly
 public inline fun $arrayTypeOf(vararg elements: $elementType): $arrayType = elements"""
         )
@@ -330,6 +336,7 @@ import kotlin.internal.*
  * A range of values of type `$elementType`.
  */
 @SinceKotlin("1.3")
+@ExperimentalUnsignedTypes
 public class ${elementType}Range(start: $elementType, endInclusive: $elementType) : ${elementType}Progression(start, endInclusive, 1), ClosedRange<${elementType}> {
     override val start: $elementType get() = first
     override val endInclusive: $elementType get() = last
@@ -357,6 +364,7 @@ public class ${elementType}Range(start: $elementType, endInclusive: $elementType
  * A progression of values of type `$elementType`.
  */
 @SinceKotlin("1.3")
+@ExperimentalUnsignedTypes
 public open class ${elementType}Progression
 internal constructor(
     start: $elementType,
@@ -413,6 +421,7 @@ internal constructor(
  * @property step the number by which the value is incremented on each step.
  */
 @SinceKotlin("1.3")
+@ExperimentalUnsignedTypes
 private class ${elementType}ProgressionIterator(first: $elementType, last: $elementType, step: $stepType) : ${elementType}Iterator() {
     private val finalElement = last
     private var hasNext: Boolean = if (step > 0) first <= last else first >= last