Add toTuple method to Product

Author: anatoliykmetyuk

library/src/dotty/DottyPredef.scala

@@ -38,4 +38,6 @@ object DottyPredef {
 
   inline def the[T] given (x: T): x.type = x
 
+  def (p: P) toTuple[P <: Product] given (m: scala.deriving.Mirror.ProductOf[P]): m.MirroredElemTypes =
+    Tuple.fromArray(p.productIterator.toArray).asInstanceOf[m.MirroredElemTypes]
 }

tests/neg/product-to-tuple.scala

@@ -0,0 +1,8 @@
+case class Foo(x: Int, y: String)
+
+val x = Foo(1, "2")
+val y: (Int, Boolean) = x.toTuple  // error
+
+case class Bar[I <: Int, S <: String](x: I, y: S)
+val a: Bar[1, "2"] = Bar(1, "2")
+val b: (1, "3") = a.toTuple  // error

tests/pos/product-to-tuple.scala

@@ -0,0 +1,8 @@
+case class Foo(x: Int, y: String)
+
+val x = Foo(1, "2")
+val y: (Int, String) = x.toTuple
+
+case class Bar[I <: Int, S <: String](x: I, y: S)
+val a: Bar[1, "2"] = Bar(1, "2")
+val b: (1, "2") = a.toTuple