Add quoted.Liftable[List[T]] to the stdlib

Author: nicolasstucki

library/src/scala/quoted/Liftable.scala

@@ -43,4 +43,11 @@ object Liftable {
     }
   }
 
+  given [T: Type: Liftable] as Liftable[List[T]] = new Liftable[List[T]] {
+    def toExpr(x: List[T]): given QuoteContext => Expr[List[T]] = x match {
+      case x :: xs  => '{ (${this.toExpr(xs)}).::[T](${the[Liftable[T]].toExpr(x)}) }
+      case Nil => '{ Nil: List[T] }
+    }
+  }
+
 }

tests/run-macros/gestalt-type-toolbox-reflect/Macro_1.scala

@@ -110,11 +110,4 @@ object TypeToolbox {
     companionClassOpt.map(_.fullName).getOrElse("").toExpr
   }
 
-  // TODO add to the std lib
-  private implicit def listIsLiftable[T: Type: Liftable]: Liftable[List[T]] = new Liftable {
-    def toExpr(list: List[T]) = list match {
-      case x :: xs => '{${x.toExpr} :: ${toExpr(xs)}}
-      case Nil => '{Nil}
-    }
-  }
 }

tests/run-macros/quote-force/quoted_1.scala

@@ -12,10 +12,4 @@ object Location {
     '{new Location(${list})}
   }
 
-  private implicit def ListIsLiftable[T : Liftable : Type]: Liftable[List[T]] = new Liftable[List[T]] {
-    def toExpr(x: List[T]) = x match {
-      case x :: xs  => '{ ${x} :: ${xs} }
-      case Nil => '{ List.empty[T] }
-    }
-  }
 }

tests/run-macros/tasty-interpolation-1/Macro.scala

@@ -77,16 +77,7 @@ abstract class MacroStringInterpolator[T] {
   }
 
   protected implicit def StringContextIsLiftable: Liftable[StringContext] = new Liftable[StringContext] {
-    def toExpr(strCtx: StringContext) = {
-      // TODO define in stdlib?
-      implicit def ListIsLiftable: Liftable[List[String]] = new Liftable[List[String]] {
-        override def toExpr(list: List[String]) = list match {
-          case x :: xs => '{${x.toExpr} :: ${toExpr(xs)}}
-          case Nil => '{Nil}
-        }
-      }
-      '{StringContext(${strCtx.parts.toList}: _*)}
-    }
+    def toExpr(strCtx: StringContext) = '{StringContext(${strCtx.parts.toList}: _*)}
   }
 
   protected class NotStaticlyKnownError(msg: String, expr: Expr[Any]) extends Exception(msg)

tests/run-macros/tasty-location/quoted_1.scala

@@ -18,10 +18,4 @@ object Location {
     '{new Location(${list})}
   }
 
-  private implicit def ListIsLiftable[T : Liftable : Type]: Liftable[List[T]] = new Liftable[List[T]] {
-    def toExpr(x: List[T]) = x match {
-      case x :: xs  => '{ $x :: $xs }
-      case Nil => '{ List.empty[T] }
-    }
-  }
 }

tests/run-with-compiler/quote-lib.scala

@@ -101,12 +101,6 @@ package liftable {
 
 
   object Lists {
-    implicit def ListIsLiftable[T: Liftable](implicit t: Type[T]): Liftable[List[T]] = new Liftable[List[T]] {
-      def toExpr(x: List[T]): given QuoteContext => Expr[List[T]] = x match {
-        case x :: xs  => '{ (${xs}).::[$t](${x}) }
-        case Nil => '{ Nil: List[$t] }
-      }
-    }
 
     implicit class LiftedOps[T: Liftable](list: Expr[List[T]])(implicit t: Type[T]) {
       def foldLeft[U](acc: Expr[U])(f: Expr[(U, T) => U])(implicit u: Type[U], qctx: QuoteContext): Expr[U] =