Use Builder.mapResult

Author: nicolasstucki

library/src/scala/IArray.scala

@@ -3,7 +3,7 @@ import reflect.ClassTag
 
 import scala.collection.{LazyZip2, SeqView, Searching, Stepper, StepperShape}
 import scala.collection.immutable.ArraySeq
-import scala.collection.mutable.IArrayBuilder
+import scala.collection.mutable.{Builder, IArrayBuilder}
 
 opaque type IArray[+T] = Array[_ <: T]
 
@@ -440,7 +440,7 @@ object IArray:
   def from[A : ClassTag](it: IterableOnce[A]): Array[A] =
     Array.from(it)
 
-  def newBuilder[T](using t: ClassTag[T]): IArrayBuilder[T] =
+  def newBuilder[T](using t: ClassTag[T]): Builder[T, IArray[T]] =
     IArrayBuilder.make[T]
 
   /** Concatenates all arrays into a single immutable array.

library/src/scala/collection/mutable/IArrayBuilder.scala

@@ -39,21 +39,8 @@ object IArrayBuilder {
   *  @tparam T     type of the elements for the array builder, with a `ClassTag` context bound.
   *  @return       a new empty array builder.
   */
-  @inline def make[T: ClassTag]: IArrayBuilder[T] = {
-    val tag = implicitly[ClassTag[T]]
-    tag.runtimeClass match {
-      case java.lang.Byte.TYPE      => new IArrayBuilder.ofByte().asInstanceOf[IArrayBuilder[T]]
-      case java.lang.Short.TYPE     => new IArrayBuilder.ofShort().asInstanceOf[IArrayBuilder[T]]
-      case java.lang.Character.TYPE => new IArrayBuilder.ofChar().asInstanceOf[IArrayBuilder[T]]
-      case java.lang.Integer.TYPE   => new IArrayBuilder.ofInt().asInstanceOf[IArrayBuilder[T]]
-      case java.lang.Long.TYPE      => new IArrayBuilder.ofLong().asInstanceOf[IArrayBuilder[T]]
-      case java.lang.Float.TYPE     => new IArrayBuilder.ofFloat().asInstanceOf[IArrayBuilder[T]]
-      case java.lang.Double.TYPE    => new IArrayBuilder.ofDouble().asInstanceOf[IArrayBuilder[T]]
-      case java.lang.Boolean.TYPE   => new IArrayBuilder.ofBoolean().asInstanceOf[IArrayBuilder[T]]
-      case java.lang.Void.TYPE      => new IArrayBuilder.ofUnit().asInstanceOf[IArrayBuilder[T]]
-      case _                        => new IArrayBuilder.ofRef[T with AnyRef]()(tag.asInstanceOf[ClassTag[T with AnyRef]]).asInstanceOf[IArrayBuilder[T]]
-    }
-  }
+  @inline def make[T: ClassTag]: Builder[T, IArray[T]] =
+    ArrayBuilder.make[T].mapResult(_.asInstanceOf[IArray[T]])
 
   /** A class for array builders for arrays of reference types.
   *