Cleanup: suppress warnings where appropriate.

libraries/stdlib/src/generated/_Arrays.kt

@@ -10823,6 +10823,7 @@ public fun <T : Any> Array<T?>.requireNoNulls(): Array<T> {
             throw IllegalArgumentException("null element found in $this.")
         }
     }
+    @Suppress("CAST_NEVER_SUCCEEDS")
     return this as Array<T>
 }
 
@@ -12531,6 +12532,7 @@ public inline fun <reified R, C : MutableCollection<in R>> Array<*>.filterIsInst
  */
 @kotlin.jvm.JvmVersion
 public fun <C : MutableCollection<in R>, R> Array<*>.filterIsInstanceTo(destination: C, klass: Class<R>): C {
+    @Suppress("UNCHECKED_CAST")
     for (element in this) if (klass.isInstance(element)) destination.add(element as R)
     return destination
 }
@@ -13002,6 +13004,7 @@ public fun ByteArray.toTypedArray(): Array<Byte> {
     val result = arrayOfNulls<Byte>(size)
     for (index in indices)
         result[index] = this[index]
+    @Suppress("CAST_NEVER_SUCCEEDS")
     return result as Array<Byte>
 }
 
@@ -13013,6 +13016,7 @@ public fun ShortArray.toTypedArray(): Array<Short> {
     val result = arrayOfNulls<Short>(size)
     for (index in indices)
         result[index] = this[index]
+    @Suppress("CAST_NEVER_SUCCEEDS")
     return result as Array<Short>
 }
 
@@ -13024,6 +13028,7 @@ public fun IntArray.toTypedArray(): Array<Int> {
     val result = arrayOfNulls<Int>(size)
     for (index in indices)
         result[index] = this[index]
+    @Suppress("CAST_NEVER_SUCCEEDS")
     return result as Array<Int>
 }
 
@@ -13035,6 +13040,7 @@ public fun LongArray.toTypedArray(): Array<Long> {
     val result = arrayOfNulls<Long>(size)
     for (index in indices)
         result[index] = this[index]
+    @Suppress("CAST_NEVER_SUCCEEDS")
     return result as Array<Long>
 }
 
@@ -13046,6 +13052,7 @@ public fun FloatArray.toTypedArray(): Array<Float> {
     val result = arrayOfNulls<Float>(size)
     for (index in indices)
         result[index] = this[index]
+    @Suppress("CAST_NEVER_SUCCEEDS")
     return result as Array<Float>
 }
 
@@ -13057,6 +13064,7 @@ public fun DoubleArray.toTypedArray(): Array<Double> {
     val result = arrayOfNulls<Double>(size)
     for (index in indices)
         result[index] = this[index]
+    @Suppress("CAST_NEVER_SUCCEEDS")
     return result as Array<Double>
 }
 
@@ -13068,6 +13076,7 @@ public fun BooleanArray.toTypedArray(): Array<Boolean> {
     val result = arrayOfNulls<Boolean>(size)
     for (index in indices)
         result[index] = this[index]
+    @Suppress("CAST_NEVER_SUCCEEDS")
     return result as Array<Boolean>
 }
 
@@ -13079,6 +13088,7 @@ public fun CharArray.toTypedArray(): Array<Char> {
     val result = arrayOfNulls<Char>(size)
     for (index in indices)
         result[index] = this[index]
+    @Suppress("CAST_NEVER_SUCCEEDS")
     return result as Array<Char>
 }
 

libraries/stdlib/src/generated/_Collections.kt

@@ -799,6 +799,7 @@ public fun <T : Comparable<T>> MutableList<T>.sortDescending(): Unit {
 public fun <T : Comparable<T>> Iterable<T>.sorted(): List<T> {
     if (this is Collection) {
         if (size <= 1) return this.toMutableList()
+        @Suppress("CAST_NEVER_SUCCEEDS")
         return (toTypedArray<Comparable<T>>() as Array<T>).apply { sort() }.asList()
     }
     return toMutableList().apply { sort() }
@@ -831,6 +832,7 @@ public fun <T : Comparable<T>> Iterable<T>.sortedDescending(): List<T> {
 public fun <T> Iterable<T>.sortedWith(comparator: Comparator<in T>): List<T> {
     if (this is Collection) {
        if (size <= 1) return this.toMutableList()
+       @Suppress("CAST_NEVER_SUCCEEDS")
        return (toTypedArray<Any?>() as Array<T>).apply { sortWith(comparator) }.asList()
     }
     return toMutableList().apply { sortWith(comparator) }
@@ -1593,6 +1595,7 @@ public fun <T : Any> Iterable<T?>.requireNoNulls(): Iterable<T> {
             throw IllegalArgumentException("null element found in $this.")
         }
     }
+    @Suppress("UNCHECKED_CAST")
     return this as Iterable<T>
 }
 
@@ -1605,6 +1608,7 @@ public fun <T : Any> List<T?>.requireNoNulls(): List<T> {
             throw IllegalArgumentException("null element found in $this.")
         }
     }
+    @Suppress("UNCHECKED_CAST")
     return this as List<T>
 }
 
@@ -1896,6 +1900,7 @@ public inline fun <reified R, C : MutableCollection<in R>> Iterable<*>.filterIsI
  */
 @kotlin.jvm.JvmVersion
 public fun <C : MutableCollection<in R>, R> Iterable<*>.filterIsInstanceTo(destination: C, klass: Class<R>): C {
+    @Suppress("UNCHECKED_CAST")
     for (element in this) if (klass.isInstance(element)) destination.add(element as R)
     return destination
 }

libraries/stdlib/src/generated/_Sequences.kt

@@ -343,6 +343,7 @@ public fun <T> Sequence<T>.filterNot(predicate: (T) -> Boolean): Sequence<T> {
  * Returns a sequence containing all elements that are not `null`.
  */
 public fun <T : Any> Sequence<T?>.filterNotNull(): Sequence<T> {
+    @Suppress("UNCHECKED_CAST")
     return filterNot { it == null } as Sequence<T>
 }
 
@@ -1179,6 +1180,7 @@ public inline fun <T> Sequence<T>.asSequence(): Sequence<T> {
  */
 @kotlin.jvm.JvmVersion
 public inline fun <reified R> Sequence<*>.filterIsInstance(): Sequence<@kotlin.internal.NoInfer R> {
+    @Suppress("UNCHECKED_CAST")
     return filter { it is R } as Sequence<R>
 }
 
@@ -1187,6 +1189,7 @@ public inline fun <reified R> Sequence<*>.filterIsInstance(): Sequence<@kotlin.i
  */
 @kotlin.jvm.JvmVersion
 public fun <R> Sequence<*>.filterIsInstance(klass: Class<R>): Sequence<R> {
+    @Suppress("UNCHECKED_CAST")
     return filter { klass.isInstance(it) } as Sequence<R>
 }
 
@@ -1204,6 +1207,7 @@ public inline fun <reified R, C : MutableCollection<in R>> Sequence<*>.filterIsI
  */
 @kotlin.jvm.JvmVersion
 public fun <C : MutableCollection<in R>, R> Sequence<*>.filterIsInstanceTo(destination: C, klass: Class<R>): C {
+    @Suppress("UNCHECKED_CAST")
     for (element in this) if (klass.isInstance(element)) destination.add(element as R)
     return destination
 }

libraries/stdlib/src/kotlin/collections/ArraysJVM.kt

@@ -18,7 +18,9 @@ public inline fun ByteArray.toString(charset: Charset): String = String(this, ch
  * Allocates an array of runtime type `T` having its size equal to the size of this collection
  * and populates the array with the elements of this collection.
  */
+@Suppress("UNCHECKED_CAST")
 public inline fun <reified T> Collection<T>.toTypedArray(): Array<T> {
+    @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN")
     val thisCollection = this as java.util.Collection<T>
     return thisCollection.toArray(arrayOfNulls<T>(thisCollection.size())) as Array<T>
 }
@@ -28,5 +30,6 @@ public inline fun <reified T> Array<out T>?.orEmpty(): Array<out T> = this ?: ar
 
 /** Internal unsafe construction of array based on reference array type */
 internal fun <T> arrayOfNulls(reference: Array<T>, size: Int): Array<T> {
+    @Suppress("UNCHECKED_CAST")
     return java.lang.reflect.Array.newInstance(reference.javaClass.componentType, size) as Array<T>
 }

libraries/stdlib/src/kotlin/collections/MapAccessors.kt

@@ -13,9 +13,8 @@ import kotlin.internal.Exact
  * @throws NoSuchElementException when the map doesn't contain value for the property name and doesn't provide an implicit default (see [withDefault]).
  */
 @kotlin.internal.InlineOnly
-@Suppress("NON_PUBLIC_CALL_FROM_PUBLIC_INLINE")
 public inline operator fun <V, V1: V> Map<in String, @Exact V>.getValue(thisRef: Any?, property: KProperty<*>): V1
-        = getOrImplicitDefault(property.name) as V1
+        = @Suppress("UNCHECKED_CAST", "NON_PUBLIC_CALL_FROM_PUBLIC_INLINE") (getOrImplicitDefault(property.name) as V1)
 
 /**
  * Returns the value of the property for the given object from this mutable map.
@@ -27,9 +26,8 @@ public inline operator fun <V, V1: V> Map<in String, @Exact V>.getValue(thisRef:
  */
 @kotlin.jvm.JvmName("getVar")
 @kotlin.internal.InlineOnly
-@Suppress("NON_PUBLIC_CALL_FROM_PUBLIC_INLINE")
 public inline operator fun <V> MutableMap<in String, in V>.getValue(thisRef: Any?, property: KProperty<*>): V
-        = getOrImplicitDefault(property.name) as V
+        = @Suppress("UNCHECKED_CAST", "NON_PUBLIC_CALL_FROM_PUBLIC_INLINE") (getOrImplicitDefault(property.name) as V)
 
 /**
  * Stores the value of the property for the given object in this mutable map.

libraries/stdlib/src/kotlin/collections/Maps.kt

@@ -25,7 +25,7 @@ private object EmptyMap : Map<Any?, Nothing>, Serializable {
 }
 
 /** Returns an empty read-only map of specified type. The returned map is serializable (JVM). */
-public fun <K, V> emptyMap(): Map<K, V> = EmptyMap as Map<K, V>
+public fun <K, V> emptyMap(): Map<K, V> = @Suppress("CAST_NEVER_SUCCEEDS") (EmptyMap as Map<K, V>)
 
 /**
  * Returns a new read-only map with the specified contents, given as a list of pairs
@@ -115,7 +115,8 @@ public inline operator fun <@kotlin.internal.OnlyInputTypes K, V> Map<out K, V>.
  * Returns the value corresponding to the given [key], or `null` if such a key is not present in the map.
  */
 @kotlin.internal.InlineOnly
-public inline operator fun <@kotlin.internal.OnlyInputTypes K, V> Map<out K, V>.get(key: K): V? = (this as Map<K, V>).get(key)
+public inline operator fun <@kotlin.internal.OnlyInputTypes K, V> Map<out K, V>.get(key: K): V?
+        = @Suppress("UNCHECKED_CAST") (this as Map<K, V>).get(key)
 
 /**
  * Returns `true` if the map contains the specified [key].
@@ -123,7 +124,8 @@ public inline operator fun <@kotlin.internal.OnlyInputTypes K, V> Map<out K, V>.
  * Allows to overcome type-safety restriction of `containsKey` that requires to pass a key of type `K`.
  */
 @kotlin.internal.InlineOnly
-public inline fun <@kotlin.internal.OnlyInputTypes K> Map<out K, *>.containsKey(key: K): Boolean = (this as Map<K, *>).containsKey(key)
+public inline fun <@kotlin.internal.OnlyInputTypes K> Map<out K, *>.containsKey(key: K): Boolean
+        = @Suppress("UNCHECKED_CAST") (this as Map<K, *>).containsKey(key)
 
 /**
  * Returns `true` if the map maps one or more keys to the specified [value].
@@ -142,7 +144,8 @@ public inline fun <K, @kotlin.internal.OnlyInputTypes V> Map<K, V>.containsValue
  * Allows to overcome type-safety restriction of `remove` that requires to pass a key of type `K`.
  */
 @kotlin.internal.InlineOnly
-public inline fun <@kotlin.internal.OnlyInputTypes K, V> MutableMap<out K, V>.remove(key: K): V? = (this as MutableMap<K, V>).remove(key)
+public inline fun <@kotlin.internal.OnlyInputTypes K, V> MutableMap<out K, V>.remove(key: K): V?
+        = @Suppress("UNCHECKED_CAST") (this as MutableMap<K, V>).remove(key)
 
 /**
  * Returns the key component of the map entry.

libraries/stdlib/src/kotlin/collections/MutableCollections.kt

@@ -14,7 +14,8 @@ import java.util.*
  * @return `true` if the element has been successfully removed; `false` if it was not present in the collection.
  */
 @kotlin.internal.InlineOnly
-public inline fun <@kotlin.internal.OnlyInputTypes T> MutableCollection<out T>.remove(element: T): Boolean = (this as MutableCollection<T>).remove(element)
+public inline fun <@kotlin.internal.OnlyInputTypes T> MutableCollection<out T>.remove(element: T): Boolean
+        = @Suppress("UNCHECKED_CAST") (this as MutableCollection<T>).remove(element)
 
 /**
  * Removes all of this collection's elements that are also contained in the specified collection.
@@ -24,7 +25,8 @@ public inline fun <@kotlin.internal.OnlyInputTypes T> MutableCollection<out T>.r
  * @return `true` if any of the specified elements was removed from the collection, `false` if the collection was not modified.
  */
 @kotlin.internal.InlineOnly
-public inline fun <@kotlin.internal.OnlyInputTypes T> MutableCollection<out T>.removeAll(elements: Collection<T>): Boolean = (this as MutableCollection<T>).removeAll(elements)
+public inline fun <@kotlin.internal.OnlyInputTypes T> MutableCollection<out T>.removeAll(elements: Collection<T>): Boolean
+        = @Suppress("UNCHECKED_CAST") (this as MutableCollection<T>).removeAll(elements)
 
 /**
  * Retains only the elements in this collection that are contained in the specified collection.
@@ -34,7 +36,8 @@ public inline fun <@kotlin.internal.OnlyInputTypes T> MutableCollection<out T>.r
  * @return `true` if any element was removed from the collection, `false` if the collection was not modified.
  */
 @kotlin.internal.InlineOnly
-public inline fun <@kotlin.internal.OnlyInputTypes T> MutableCollection<out T>.retainAll(elements: Collection<T>): Boolean = (this as MutableCollection<T>).retainAll(elements)
+public inline fun <@kotlin.internal.OnlyInputTypes T> MutableCollection<out T>.retainAll(elements: Collection<T>): Boolean
+        = @Suppress("UNCHECKED_CAST") (this as MutableCollection<T>).retainAll(elements)
 
 /**
  * Adds the specified [element] to this mutable collection.

libraries/stdlib/src/kotlin/comparisons/Comparisons.kt

@@ -74,6 +74,7 @@ public fun <T : Comparable<*>> compareValues(a: T?, b: T?): Int {
     if (a == null) return -1
     if (b == null) return 1
 
+    @Suppress("UNCHECKED_CAST")
     return (a as Comparable<Any>).compareTo(b)
 }
 
@@ -279,18 +280,18 @@ public inline fun <T: Comparable<T>> nullsLast(): Comparator<T?> = nullsLast(nat
 /**
  * Returns a comparator that compares [Comparable] objects in natural order.
  */
-public fun <T: Comparable<T>> naturalOrder(): Comparator<T> = NaturalOrderComparator as Comparator<T>
+public fun <T: Comparable<T>> naturalOrder(): Comparator<T> = @Suppress("CAST_NEVER_SUCCEEDS") (NaturalOrderComparator as Comparator<T>)
 
 /**
  * Returns a comparator that compares [Comparable] objects in reversed natural order.
  */
-public fun <T: Comparable<T>> reverseOrder(): Comparator<T> = ReverseOrderComparator as Comparator<T>
+public fun <T: Comparable<T>> reverseOrder(): Comparator<T> = @Suppress("CAST_NEVER_SUCCEEDS") (ReverseOrderComparator as Comparator<T>)
 
 /** Returns a comparator that imposes the reverse ordering of this comparator. */
 public fun <T> Comparator<T>.reversed(): Comparator<T> = when (this) {
     is ReversedComparator -> this.comparator
-    NaturalOrderComparator -> ReverseOrderComparator as Comparator<T>
+    NaturalOrderComparator -> @Suppress("CAST_NEVER_SUCCEEDS") (ReverseOrderComparator as Comparator<T>)
-    ReverseOrderComparator -> NaturalOrderComparator as Comparator<T>
+    ReverseOrderComparator -> @Suppress("CAST_NEVER_SUCCEEDS") (NaturalOrderComparator as Comparator<T>)
     else -> ReversedComparator(this)
 }
 

libraries/stdlib/src/kotlin/jvm/internal/unsafe/monitor.kt

@@ -17,7 +17,7 @@
 package kotlin.jvm.internal.unsafe
 
 @kotlin.internal.InlineExposed
-internal fun monitorEnter(monitor: Any): Unit = throw UnsupportedOperationException("This function can only be used privately")
+internal fun monitorEnter(@Suppress("UNUSED_PARAMETER") monitor: Any): Unit = throw UnsupportedOperationException("This function can only be used privately")
 
 @kotlin.internal.InlineExposed
-internal fun monitorExit(monitor: Any): Unit = throw UnsupportedOperationException("This function can only be used privately")
+internal fun monitorExit(@Suppress("UNUSED_PARAMETER") monitor: Any): Unit = throw UnsupportedOperationException("This function can only be used privately")

libraries/stdlib/src/kotlin/util/Lazy.kt

@@ -118,13 +118,14 @@ private class SynchronizedLazyImpl<out T>(initializer: () -> T, lock: Any? = nul
         get() {
             val _v1 = _value
             if (_v1 !== UNINITIALIZED_VALUE) {
+                @Suppress("UNCHECKED_CAST")
                 return _v1 as T
             }
 
             return synchronized(lock) {
                 val _v2 = _value
                 if (_v2 !== UNINITIALIZED_VALUE) {
-                     _v2 as T
+                    @Suppress("UNCHECKED_CAST") (_v2 as T)
                 }
                 else {
                     val typedValue = initializer!!()
@@ -153,6 +154,7 @@ internal class UnsafeLazyImpl<out T>(initializer: () -> T) : Lazy<T>, Serializab
                 _value = initializer!!()
                 initializer = null
             }
+            @Suppress("UNCHECKED_CAST")
             return _value as T
         }
 
@@ -190,6 +192,7 @@ private class SafePublicationLazyImpl<out T>(initializer: () -> T) : Lazy<T>, Se
                     }
                 }
             }
+            @Suppress("UNCHECKED_CAST")
             return _value as T
         }
 

libraries/tools/kotlin-stdlib-gen/src/templates/Filtering.kt

@@ -529,6 +529,7 @@ fun filtering(): List<GenericFunction> {
         returns(Sequences) { "Sequence<T>" }
         body(Sequences) {
             """
+            @Suppress("UNCHECKED_CAST")
             return filterNot { it == null } as Sequence<T>
             """
         }

libraries/tools/kotlin-stdlib-gen/src/templates/Guards.kt

@@ -13,13 +13,14 @@ fun guards(): List<GenericFunction> {
         typeParam("T : Any")
         toNullableT = true
         returns("SELF")
-        body {
+        body { f ->
             """
             for (element in this) {
                 if (element == null) {
                     throw IllegalArgumentException("null element found in $THIS.")
                 }
             }
+            @Suppress("${if (f == InvariantArraysOfObjects) "CAST_NEVER_SUCCEEDS" else "UNCHECKED_CAST"}")
             return this as SELF
             """
         }

libraries/tools/kotlin-stdlib-gen/src/templates/Ordering.kt

@@ -102,6 +102,7 @@ fun ordering(): List<GenericFunction> {
             """
                 if (this is Collection) {
                     if (size <= 1) return this.toMutableList()
+                    @Suppress("CAST_NEVER_SUCCEEDS")
                     return (toTypedArray<Comparable<T>>() as Array<T>).apply { sort() }.asList()
                 }
                 return toMutableList().apply { sort() }
@@ -231,6 +232,7 @@ fun ordering(): List<GenericFunction> {
             """
              if (this is Collection) {
                 if (size <= 1) return this.toMutableList()
+                @Suppress("CAST_NEVER_SUCCEEDS")
                 return (toTypedArray<Any?>() as Array<T>).apply { sortWith(comparator) }.asList()
             }
             return toMutableList().apply { sortWith(comparator) }

libraries/tools/kotlin-stdlib-gen/src/templates/SpecialJVM.kt

@@ -202,6 +202,7 @@ fun specialJVM(): List<GenericFunction> {
         exclude(ArraysOfPrimitives, Strings)
         body {
             """
+            @Suppress("UNCHECKED_CAST")
             for (element in this) if (klass.isInstance(element)) destination.add(element as R)
             return destination
             """
@@ -224,6 +225,7 @@ fun specialJVM(): List<GenericFunction> {
         returns(Sequences) { "Sequence<R>" }
         body(Sequences) {
             """
+            @Suppress("UNCHECKED_CAST")
             return filter { klass.isInstance(it) } as Sequence<R>
             """
         }
@@ -264,6 +266,7 @@ fun specialJVM(): List<GenericFunction> {
         receiverAsterisk(true)
         body(Sequences) {
             """
+            @Suppress("UNCHECKED_CAST")
             return filter { it is R } as Sequence<R>
             """
         }
@@ -307,6 +310,7 @@ fun specialJVM(): List<GenericFunction> {
             val result = arrayOfNulls<T>(size)
             for (index in indices)
                 result[index] = this[index]
+            @Suppress("CAST_NEVER_SUCCEEDS")
             return result as Array<T>
             """
         }