Add toExprOfTuple method for tuples

Author: anatoliykmetyuk

compiler/test/dotc/pos-test-pickling.blacklist

@@ -24,3 +24,6 @@ matchtype.scala
 
 # Opaque type
 i5720.scala
+
+# Tuples
+toexproftuple.scala

library/src-bootstrapped/scala/quoted/package.scala

@@ -140,4 +140,9 @@ package object quoted {
     }
   }
 
+  def (tup: T) toExprOfTuple[T <: Tuple] given (ctx: QuoteContext, t: Type[Tuple.ReverseMap[T, Expr]]): Expr[Tuple.ReverseMap[T, Expr]] = {
+    import ctx.tasty._
+    val res: Expr[Tuple] = tup.asInstanceOf[Product].productIterator.toSeq.asInstanceOf[Seq[Expr[_]]].toExprOfTuple
+    res.cast[Tuple.ReverseMap[T, Expr]]
+  }
 }

library/src/scala/Tuple.scala

@@ -74,6 +74,12 @@ object Tuple {
     case h *: t => F[h] *: Map[t, F]
   }
 
+  /** Converts a tuple `(F[T1], ..., F[Tn])` to `(T1,  ... Tn)` */
+  type ReverseMap[X <: Tuple, F[_]] <: Tuple = X match {
+    case F[x] *: t => x *: ReverseMap[t, F]
+    case Unit => Unit
+  }
+
   /** Convert an array into a tuple of unknown arity and types */
   def fromArray[T](xs: Array[T]): Tuple = {
     val xs2 = xs match {

tests/neg/toexproftuple.scala

@@ -0,0 +1,8 @@
+import scala.quoted._, scala.deriving._
+import given scala.quoted._
+
+inline def mcr: Any = ${mcrImpl}
+def mcrImpl given (ctx: QuoteContext): Expr[Any] = {
+  val tpl: (Expr[1], Expr[2], Expr[3]) = ('{1}, '{2}, '{3})
+  '{val res: (1, 3, 3) = ${tpl.toExprOfTuple}; res}  // error
+}

tests/pos/toexproftuple.scala

@@ -0,0 +1,8 @@
+import scala.quoted._, scala.deriving._
+import given scala.quoted._
+
+inline def mcr: Any = ${mcrImpl}
+def mcrImpl given (ctx: QuoteContext): Expr[Any] = {
+  val tpl: (Expr[1], Expr[2], Expr[3]) = ('{1}, '{2}, '{3})
+  '{val res: (1, 2, 3) = ${tpl.toExprOfTuple}; res}
+}