Introduce associateTo and associateByTo with the destination MutableMap to fill.

libraries/stdlib/src/generated/_Collections.kt

@@ -914,16 +914,13 @@ public fun Collection<Short>.toShortArray(): ShortArray {
 }
 
 /**
- * Returns a [Map] containing key-value pairs provided by [transform] function applied to elements of the given collection.
+ * Returns a [Map] containing key-value pairs provided by [transform] function
+ * applied to elements of the given collection.
  * If any of two pairs would have the same key the last one gets added to the map.
  */
 public inline fun <T, K, V> Iterable<T>.associate(transform: (T) -> Pair<K, V>): Map<K, V> {
-    val capacity = (collectionSizeOrDefault(10)/.75f) + 1
-    val result = LinkedHashMap<K, V>(Math.max(capacity.toInt(), 16))
-    for (element in this) {
-        result += transform(element)
-    }
-    return result
+    val capacity = ((collectionSizeOrDefault(10)/.75f) + 1).toInt().coerceAtLeast(16)
+    return associateTo(LinkedHashMap<K, V>(capacity), transform)
 }
 
 /**
@@ -932,12 +929,8 @@ public inline fun <T, K, V> Iterable<T>.associate(transform: (T) -> Pair<K, V>):
  * If any two elements would have the same key returned by [keySelector] the last one gets added to the map.
  */
 public inline fun <T, K> Iterable<T>.associateBy(keySelector: (T) -> K): Map<K, T> {
-    val capacity = (collectionSizeOrDefault(10)/.75f) + 1
-    val result = LinkedHashMap<K, T>(Math.max(capacity.toInt(), 16))
-    for (element in this) {
-        result.put(keySelector(element), element)
-    }
-    return result
+    val capacity = ((collectionSizeOrDefault(10)/.75f) + 1).toInt().coerceAtLeast(16)
+    return associateByTo(LinkedHashMap<K, T>(capacity), keySelector)
 }
 
 /**
@@ -945,12 +938,46 @@ public inline fun <T, K> Iterable<T>.associateBy(keySelector: (T) -> K): Map<K,
  * If any two elements would have the same key returned by [keySelector] the last one gets added to the map.
  */
 public inline fun <T, K, V> Iterable<T>.associateBy(keySelector: (T) -> K, valueTransform: (T) -> V): Map<K, V> {
-    val capacity = (collectionSizeOrDefault(10)/.75f) + 1
-    val result = LinkedHashMap<K, V>(Math.max(capacity.toInt(), 16))
+    val capacity = ((collectionSizeOrDefault(10)/.75f) + 1).toInt().coerceAtLeast(16)
+    return associateByTo(LinkedHashMap<K, V>(capacity), keySelector, valueTransform)
+}
+
+/**
+ * Populates and returns the [destination] mutable map with key-value pairs,
+ * where key is provided by the [keySelector] function applied to each element of the given collection
+ * and value is the element itself.
+ * If any two elements would have the same key returned by [keySelector] the last one gets added to the map.
+ */
+public inline fun <T, K, M : MutableMap<in K, in T>> Iterable<T>.associateByTo(destination: M, keySelector: (T) -> K): M {
     for (element in this) {
-        result.put(keySelector(element), valueTransform(element))
+        destination.put(keySelector(element), element)
     }
-    return result
+    return destination
+}
+
+/**
+ * Populates and returns the [destination] mutable map with key-value pairs,
+ * where key is provided by the [keySelector] function and
+ * and value is provided by the [valueTransform] function applied to elements of the given collection.
+ * If any two elements would have the same key returned by [keySelector] the last one gets added to the map.
+ */
+public inline fun <T, K, V, M : MutableMap<in K, in V>> Iterable<T>.associateByTo(destination: M, keySelector: (T) -> K, valueTransform: (T) -> V): M {
+    for (element in this) {
+        destination.put(keySelector(element), valueTransform(element))
+    }
+    return destination
+}
+
+/**
+ * Populates and returns the [destination] mutable map with key-value pairs
+ * provided by [transform] function applied to each element of the given collection.
+ * If any of two pairs would have the same key the last one gets added to the map.
+ */
+public inline fun <T, K, V, M : MutableMap<in K, in V>> Iterable<T>.associateTo(destination: M, transform: (T) -> Pair<K, V>): M {
+    for (element in this) {
+        destination += transform(element)
+    }
+    return destination
 }
 
 /**