diff --git a/compiler/src/dotty/tools/dotc/ast/Desugar.scala b/compiler/src/dotty/tools/dotc/ast/Desugar.scala
index 35e62d523894..bc4a1d62ef06 100644
--- a/compiler/src/dotty/tools/dotc/ast/Desugar.scala
+++ b/compiler/src/dotty/tools/dotc/ast/Desugar.scala
@@ -1153,17 +1153,21 @@ object desugar {
    *   - all pattern, value and method definitions
    *   - non-class type definitions
    *   - implicit classes and objects
-   *   - companion objects of opaque types
+   *   - "companion objects" of wrapped type definitions
+   *     (i.e. objects having the same name as a wrapped type)
    */
   def packageDef(pdef: PackageDef)(implicit ctx: Context): PackageDef = {
-    val opaqueNames = pdef.stats.collect {
-      case stat: TypeDef if stat.mods.is(Opaque) => stat.name
+    def isWrappedType(stat: TypeDef): Boolean =
+      !stat.isClassDef || stat.mods.isOneOf(DelegateOrImplicit)
+    val wrappedTypeNames = pdef.stats.collect {
+      case stat: TypeDef if isWrappedType(stat) => stat.name
     }
     def needsObject(stat: Tree) = stat match {
       case _: ValDef | _: PatDef | _: DefDef | _: Export => true
       case stat: ModuleDef =>
-        stat.mods.isOneOf(DelegateOrImplicit) || opaqueNames.contains(stat.name.stripModuleClassSuffix.toTypeName)
-      case stat: TypeDef => !stat.isClassDef || stat.mods.isOneOf(DelegateOrImplicit)
+        stat.mods.isOneOf(DelegateOrImplicit) ||
+        wrappedTypeNames.contains(stat.name.stripModuleClassSuffix.toTypeName)
+      case stat: TypeDef => isWrappedType(stat)
       case _ => false
     }
     val (nestedStats, topStats) = pdef.stats.partition(needsObject)
diff --git a/library/src-bootstrapped/scala/IArray.scala b/library/src-bootstrapped/scala/IArray.scala
index 16d92077b9ad..d6f0156136f3 100644
--- a/library/src-bootstrapped/scala/IArray.scala
+++ b/library/src-bootstrapped/scala/IArray.scala
@@ -4,66 +4,70 @@ import reflect.ClassTag
 /** An immutable array. An `IArray[T]` has the same representation as an `Array[T]`,
  *  but it cannot be updated. Unlike regular arrays, immutable arrays are covariant.
  */
-opaque type IArray[+T] = Array[_ <: T]
-
-/** Defines extension methods for immutable arrays */
-implicit object arrayOps {
-
-  /** The selection operation on an immutable array.
-    *
-    *  @param arr the immutable array
-    *  @param n   the index of the element to select
-    *  @return    the element of the array at the given index
-    */
-  def (arr: IArray[Byte]) apply (n: Int): Byte = arr.asInstanceOf[Array[Byte]].apply(n)
-  def (arr: IArray[Short]) apply (n: Int): Short = arr.asInstanceOf[Array[Short]].apply(n)
-  def (arr: IArray[Char]) apply (n: Int): Char = arr.asInstanceOf[Array[Char]].apply(n)
-  def (arr: IArray[Int]) apply (n: Int): Int = arr.asInstanceOf[Array[Int]].apply(n)
-  def (arr: IArray[Long]) apply (n: Int): Long = arr.asInstanceOf[Array[Long]].apply(n)
-  def (arr: IArray[Float]) apply (n: Int): Float = arr.asInstanceOf[Array[Float]].apply(n)
-  def (arr: IArray[Double]) apply (n: Int): Double = arr.asInstanceOf[Array[Double]].apply(n)
-  def (arr: IArray[T]) apply[T <: Object] (n: Int): T = arr.asInstanceOf[Array[T]].apply(n)
-  def (arr: IArray[T]) apply[T] (n: Int): T = arr.asInstanceOf[Array[T]].apply(n)
-
-  /** The number of elements in an immutable array
-    *  @param arr  the immutable array
-    */
-  def (arr: IArray[Byte]) length: Int = arr.asInstanceOf[Array[Byte]].length
-  def (arr: IArray[Short]) length: Int = arr.asInstanceOf[Array[Short]].length
-  def (arr: IArray[Char]) length: Int = arr.asInstanceOf[Array[Char]].length
-  def (arr: IArray[Int]) length: Int = arr.asInstanceOf[Array[Int]].length
-  def (arr: IArray[Long]) length: Int = arr.asInstanceOf[Array[Long]].length
-  def (arr: IArray[Float]) length: Int = arr.asInstanceOf[Array[Float]].length
-  def (arr: IArray[Double]) length: Int = arr.asInstanceOf[Array[Double]].length
-  def (arr: IArray[Object]) length: Int = arr.asInstanceOf[Array[Object]].length
-  def (arr: IArray[T]) length[T] : Int = arr.asInstanceOf[Array[T]].length
+object opaques {
+  opaque type IArray[+T] = Array[_ <: T]
+
+  /** Defines extension methods for immutable arrays */
+  given arrayOps {
+
+    /** The selection operation on an immutable array.
+      *
+      *  @param arr the immutable array
+      *  @param n   the index of the element to select
+      *  @return    the element of the array at the given index
+      */
+    def (arr: IArray[Byte]) apply (n: Int): Byte = arr.asInstanceOf[Array[Byte]].apply(n)
+    def (arr: IArray[Short]) apply (n: Int): Short = arr.asInstanceOf[Array[Short]].apply(n)
+    def (arr: IArray[Char]) apply (n: Int): Char = arr.asInstanceOf[Array[Char]].apply(n)
+    def (arr: IArray[Int]) apply (n: Int): Int = arr.asInstanceOf[Array[Int]].apply(n)
+    def (arr: IArray[Long]) apply (n: Int): Long = arr.asInstanceOf[Array[Long]].apply(n)
+    def (arr: IArray[Float]) apply (n: Int): Float = arr.asInstanceOf[Array[Float]].apply(n)
+    def (arr: IArray[Double]) apply (n: Int): Double = arr.asInstanceOf[Array[Double]].apply(n)
+    def (arr: IArray[T]) apply[T <: Object] (n: Int): T = arr.asInstanceOf[Array[T]].apply(n)
+    def (arr: IArray[T]) apply[T] (n: Int): T = arr.asInstanceOf[Array[T]].apply(n)
+
+    /** The number of elements in an immutable array
+      *  @param arr  the immutable array
+      */
+    def (arr: IArray[Byte]) length: Int = arr.asInstanceOf[Array[Byte]].length
+    def (arr: IArray[Short]) length: Int = arr.asInstanceOf[Array[Short]].length
+    def (arr: IArray[Char]) length: Int = arr.asInstanceOf[Array[Char]].length
+    def (arr: IArray[Int]) length: Int = arr.asInstanceOf[Array[Int]].length
+    def (arr: IArray[Long]) length: Int = arr.asInstanceOf[Array[Long]].length
+    def (arr: IArray[Float]) length: Int = arr.asInstanceOf[Array[Float]].length
+    def (arr: IArray[Double]) length: Int = arr.asInstanceOf[Array[Double]].length
+    def (arr: IArray[Object]) length: Int = arr.asInstanceOf[Array[Object]].length
+    def (arr: IArray[T]) length[T] : Int = arr.asInstanceOf[Array[T]].length
+  }
 }
+type IArray[+T] = opaques.IArray[T]
 
 object IArray {
 
   /** An immutable array of length 0.
    */
-  def empty[T: ClassTag]: IArray[T] = new Array[T](0)
+  def empty[T: ClassTag]: IArray[T] = new Array[T](0).asInstanceOf
 
   /** An immutable array with given elements.
    */
-  def apply[T: ClassTag](xs: T*): IArray[T] = Array(xs: _*)
-  def apply(x: Boolean, xs: Boolean*): IArray[Boolean] = Array(x, xs: _*)
-  def apply(x: Byte, xs: Byte*): IArray[Byte] = Array(x, xs: _*)
-  def apply(x: Short, xs: Short*): IArray[Short] = Array(x, xs: _*)
-  def apply(x: Char, xs: Char*): IArray[Char] = Array(x, xs: _*)
-  def apply(x: Int, xs: Int*): IArray[Int] = Array(x, xs: _*)
-  def apply(x: Long, xs: Long*): IArray[Long] = Array(x, xs: _*)
-  def apply(x: Float, xs: Float*): IArray[Float] = Array(x, xs: _*)
-  def apply(x: Double, xs: Double*): IArray[Double] = Array(x, xs: _*)
-  def apply(x: Unit, xs: Unit*): IArray[Unit] = Array(x, xs: _*)
+  def apply[T: ClassTag](xs: T*): IArray[T] = Array(xs: _*).asInstanceOf
+  def apply(x: Boolean, xs: Boolean*): IArray[Boolean] = Array(x, xs: _*).asInstanceOf
+  def apply(x: Byte, xs: Byte*): IArray[Byte] = Array(x, xs: _*).asInstanceOf
+  def apply(x: Short, xs: Short*): IArray[Short] = Array(x, xs: _*).asInstanceOf
+  def apply(x: Char, xs: Char*): IArray[Char] = Array(x, xs: _*).asInstanceOf
+  def apply(x: Int, xs: Int*): IArray[Int] = Array(x, xs: _*).asInstanceOf
+  def apply(x: Long, xs: Long*): IArray[Long] = Array(x, xs: _*).asInstanceOf
+  def apply(x: Float, xs: Float*): IArray[Float] = Array(x, xs: _*).asInstanceOf
+  def apply(x: Double, xs: Double*): IArray[Double] = Array(x, xs: _*).asInstanceOf
+  def apply(x: Unit, xs: Unit*): IArray[Unit] = Array(x, xs: _*).asInstanceOf
 
   /** Concatenates all arrays into a single immutable array.
    *
    *  @param xss the given immutable arrays
    *  @return   the array created from concatenating `xss`
    */
-  def concat[T: ClassTag](xss: IArray[T]*): IArray[T] = Array.concat[T](xss.asInstanceOf[Seq[Array[T]]]: _*)
+  def concat[T: ClassTag](xss: IArray[T]*): IArray[T] =
+    Array.concat[T](xss.asInstanceOf[Seq[Array[T]]]: _*).asInstanceOf
 
   /** Returns an immutable array that contains the results of some element computation a number
    *  of times. Each element is determined by a separate computation.
@@ -72,7 +76,7 @@ object IArray {
    *  @param   elem the element computation
    */
   def fill[T: ClassTag](n: Int)(elem: => T): IArray[T] =
-    Array.fill(n)(elem)
+    Array.fill(n)(elem).asInstanceOf
 
   /** Returns a two-dimensional immutable array that contains the results of some element computation a number
    *  of times. Each element is determined by a separate computation.
@@ -82,7 +86,7 @@ object IArray {
    *  @param   elem the element computation
    */
   def fill[T: ClassTag](n1: Int, n2: Int)(elem: => T): IArray[IArray[T]] =
-    Array.fill(n1, n2)(elem)
+    Array.fill(n1, n2)(elem).asInstanceOf
 
   /** Returns a three-dimensional immutable array that contains the results of some element computation a number
    *  of times. Each element is determined by a separate computation.
@@ -93,7 +97,7 @@ object IArray {
    *  @param   elem the element computation
    */
   def fill[T: ClassTag](n1: Int, n2: Int, n3: Int)(elem: => T): IArray[IArray[IArray[T]]] =
-    Array.fill(n1, n2, n3)(elem)
+    Array.fill(n1, n2, n3)(elem).asInstanceOf
 
   /** Returns a four-dimensional immutable array that contains the results of some element computation a number
    *  of times. Each element is determined by a separate computation.
@@ -105,7 +109,7 @@ object IArray {
    *  @param   elem the element computation
    */
   def fill[T: ClassTag](n1: Int, n2: Int, n3: Int, n4: Int)(elem: => T): IArray[IArray[IArray[IArray[T]]]] =
-    Array.fill(n1, n2, n3, n4)(elem)
+    Array.fill(n1, n2, n3, n4)(elem).asInstanceOf
 
   /** Returns a five-dimensional immutable array that contains the results of some element computation a number
    *  of times. Each element is determined by a separate computation.
@@ -118,7 +122,7 @@ object IArray {
    *  @param   elem the element computation
    */
   def fill[T: ClassTag](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(elem: => T): IArray[IArray[IArray[IArray[IArray[T]]]]] =
-    Array.fill(n1, n2, n3, n4, n5)(elem)
+    Array.fill(n1, n2, n3, n4, n5)(elem).asInstanceOf
 
   /** Returns an immutable array containing values of a given function over a range of integer
    *  values starting from 0.
@@ -127,7 +131,7 @@ object IArray {
    *  @param  f   The function computing element values
    */
   def tabulate[T: ClassTag](n: Int)(f: Int => T): IArray[T] =
-    Array.tabulate(n)(f)
+    Array.tabulate(n)(f).asInstanceOf
 
   /** Returns a two-dimensional immutable array containing values of a given function
    *  over ranges of integer values starting from `0`.
@@ -137,7 +141,7 @@ object IArray {
    *  @param   f   The function computing element values
    */
   def tabulate[T: ClassTag](n1: Int, n2: Int)(f: (Int, Int) => T): IArray[IArray[T]] =
-    Array.tabulate(n1, n2)(f)
+    Array.tabulate(n1, n2)(f).asInstanceOf
 
   /** Returns a three-dimensional immutable array containing values of a given function
    *  over ranges of integer values starting from `0`.
@@ -148,7 +152,7 @@ object IArray {
    *  @param   f   The function computing element values
    */
   def tabulate[T: ClassTag](n1: Int, n2: Int, n3: Int)(f: (Int, Int, Int) => T): IArray[IArray[IArray[T]]] =
-    Array.tabulate(n1, n2, n3)(f)
+    Array.tabulate(n1, n2, n3)(f).asInstanceOf
 
   /** Returns a four-dimensional immutable array containing values of a given function
    *  over ranges of integer values starting from `0`.
@@ -160,7 +164,7 @@ object IArray {
    *  @param   f   The function computing element values
    */
   def tabulate[T: ClassTag](n1: Int, n2: Int, n3: Int, n4: Int)(f: (Int, Int, Int, Int) => T): IArray[IArray[IArray[IArray[T]]]] =
-    Array.tabulate(n1, n2, n3, n4)(f)
+    Array.tabulate(n1, n2, n3, n4)(f).asInstanceOf
 
   /** Returns a five-dimensional immutable array containing values of a given function
    *  over ranges of integer values starting from `0`.
@@ -173,7 +177,7 @@ object IArray {
    *  @param   f   The function computing element values
    */
   def tabulate[T: ClassTag](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(f: (Int, Int, Int, Int, Int) => T): IArray[IArray[IArray[IArray[IArray[T]]]]] =
-    Array.tabulate(n1, n2, n3, n4, n5)(f)
+    Array.tabulate(n1, n2, n3, n4, n5)(f).asInstanceOf
 
   /** Returns an immutable array containing a sequence of increasing integers in a range.
    *
@@ -182,7 +186,7 @@ object IArray {
    *  @return  the immutable array with values in range `start, start + 1, ..., end - 1`
    *  up to, but excluding, `end`.
    */
-  def range(start: Int, end: Int): IArray[Int] = Array.range(start, end)
+  def range(start: Int, end: Int): IArray[Int] = Array.range(start, end).asInstanceOf
 
   /** Returns an immutable array containing equally spaced values in some integer interval.
    *
@@ -191,7 +195,7 @@ object IArray {
    *  @param step  the increment value of the array (may not be zero)
    *  @return      the immutable array with values in `start, start + step, ...` up to, but excluding `end`
    */
-  def range(start: Int, end: Int, step: Int): IArray[Int] = Array.range(start, end, step)
+  def range(start: Int, end: Int, step: Int): IArray[Int] = Array.range(start, end, step).asInstanceOf
 
   /** Returns an immutable array containing repeated applications of a function to a start value.
    *
@@ -200,7 +204,7 @@ object IArray {
    *  @param f     the function that is repeatedly applied
    *  @return      the immutable array returning `len` values in the sequence `start, f(start), f(f(start)), ...`
    */
-  def iterate[T: ClassTag](start: T, len: Int)(f: T => T): IArray[T] = Array.iterate(start, len)(f)
+  def iterate[T: ClassTag](start: T, len: Int)(f: T => T): IArray[T] = Array.iterate(start, len)(f).asInstanceOf
 
   /** Returns a decomposition of the array into a sequence. This supports
    *  a pattern match like `{ case IArray(x,y,z) => println('3 elements')}`.