Remove quoted.Const.unapply

This extractor was replaced with the more versatil extractor `quoted.Unlifted.unapply`.

* Remove definition of `quoted.Const.unapply`
* Replace uses of `Const` with `Unlifted`
* Allow unlifting precise types for primitives
* Remove `Unlifted[Unit]`

**Migration**

* Replace `Const(x)` with `Unlifted(x)` if the type is known
* Replace `Const(x: Int)` with `'{ ${Unlifted(x)}: Int }` if type of expression must be checked at runtime
* Consider using `expr.unlift` and them match on `Option`

Author: nicolasstucki

community-build/community-projects/scalatest

@@ -14,39 +14,46 @@ trait Unliftable[T] {
 
 object Unliftable {
 
-  /** Default unliftable for Unit */
-  given UnitUnliftable as Unliftable[Unit] = new PrimitiveUnliftable
-
   /** Default unliftable for Boolean */
-  given BooleanUnliftable as Unliftable[Boolean] = new PrimitiveUnliftable
+  given BooleanUnliftable[T <: Boolean] as Unliftable[T] = new PrimitiveUnliftable
 
   /** Default unliftable for Byte */
-  given ByteUnliftable as Unliftable[Byte] = new PrimitiveUnliftable
+  given ByteUnliftable[T <: Byte] as Unliftable[T] = new PrimitiveUnliftable
 
   /** Default unliftable for Short */
-  given ShortUnliftable as Unliftable[Short] = new PrimitiveUnliftable
+  given ShortUnliftable[T <: Short] as Unliftable[T] = new PrimitiveUnliftable
 
   /** Default unliftable for Int */
-  given IntUnliftable as Unliftable[Int] = new PrimitiveUnliftable
+  given IntUnliftable[T <: Int] as Unliftable[T] = new PrimitiveUnliftable
 
   /** Default unliftable for Long */
-  given LongUnliftable as Unliftable[Long] = new PrimitiveUnliftable
+  given LongUnliftable[T <: Long] as Unliftable[T] = new PrimitiveUnliftable
 
   /** Default unliftable for Float */
-  given FloatUnliftable as Unliftable[Float] = new PrimitiveUnliftable
+  given FloatUnliftable[T <: Float] as Unliftable[T] = new PrimitiveUnliftable
 
   /** Default unliftable for Double */
-  given DoubleUnliftable as Unliftable[Double] = new PrimitiveUnliftable
+  given DoubleUnliftable[T <: Double] as Unliftable[T] = new PrimitiveUnliftable
 
   /** Default unliftable for Char */
-  given CharUnliftable as Unliftable[Char] = new PrimitiveUnliftable
+  given CharUnliftable[T <: Char] as Unliftable[T] = new PrimitiveUnliftable
 
   /** Default unliftable for String */
-  given StringUnliftable as Unliftable[String] = new PrimitiveUnliftable
+  given StringUnliftable[T <: String] as Unliftable[T] = new PrimitiveUnliftable
 
-  private class PrimitiveUnliftable[T <: Unit | Null | Int | Boolean | Byte | Short | Int | Long | Float | Double | Char | String] extends Unliftable[T] {
+  private class PrimitiveUnliftable[T <: Int | Boolean | Byte | Short | Int | Long | Float | Double | Char | String] extends Unliftable[T] {
     /** Lift a quoted primitive value `'{ n }` into `n` */
-    def fromExpr(x: Expr[T]) = Const.unapply(x)
+    def fromExpr(expr: Expr[T]) = {
+      import quotes.reflect._
+      def rec(tree: Term): Option[T] = tree match {
+        case Literal(c) => Some(c.value.asInstanceOf[T])
+        case Block(Nil, e) => rec(e)
+        case Typed(e, _) => rec(e)
+        case Inlined(_, Nil, e) => rec(e)
+        case _  => None
+      }
+      rec(Term.of(expr))
+    }
   }
 
   /** Default unliftable for Option */
@@ -79,8 +86,8 @@ object Unliftable {
   /** Default unliftable for StringContext */
   given StringContextUnliftable as Unliftable[StringContext] = new {
     def fromExpr(x: Expr[StringContext]) = x match {
-      case '{ new StringContext(${Varargs(Consts(args))}: _*) } => Some(StringContext(args: _*))
-      case '{     StringContext(${Varargs(Consts(args))}: _*) } => Some(StringContext(args: _*))
+      case '{ new StringContext(${Varargs(Unlifted(args))}: _*) } => Some(StringContext(args: _*))
+      case '{     StringContext(${Varargs(Unlifted(args))}: _*) } => Some(StringContext(args: _*))
       case _ => None
     }
   }

community-build/community-projects/xml-interpolator

@@ -9,7 +9,7 @@ object Macro {
     var res: Expr[String] = null
     for _ <- 0 to 5_000 do
       (strCtxExpr, argsExpr) match {
-        case ('{ StringContext(${Varargs(Consts(parts))}: _*) }, Varargs(Consts(args))) =>
+        case ('{ StringContext(${Varargs(Unlifted(parts))}: _*) }, Varargs(Unlifted(args))) =>
           res = Expr(StringContext(parts: _*).s(args: _*))
         case _ => ???
       }

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

@@ -6,7 +6,7 @@ import scala.quoted._
 object BigFloatFromDigitsImpl:
   def apply(digits: Expr[String])(using Quotes): Expr[BigFloat] =
     digits match
-      case Const(ds) =>
+      case Unlifted(ds) =>
         try
           val BigFloat(m, e) = BigFloat(ds)
           '{BigFloat(${Expr(m)}, ${Expr(e)})}

library/src/scala/quoted/Const.scala

@@ -5,7 +5,7 @@ import Even._
 
 object EvenFromDigitsImpl:
   def apply(digits: Expr[String])(using Quotes): Expr[Even] = digits match {
-    case Const(ds) =>
+    case Unlifted(ds) =>
       val ev =
         try evenFromDigits(ds)
         catch {

library/src/scala/quoted/Consts.scala

@@ -9,7 +9,7 @@ object Macro {
     import quotes.reflect._
     sc match {
       case '{ StringContext(${Varargs(parts)}: _*) } =>
-        for (part @ Const(s) <- parts)
+        for (part @ Unlifted(s) <- parts)
           report.error(s, Term.of(part).pos)
     }
     '{}

tests/bench/string-interpolation-macro/Macro.scala

@@ -9,7 +9,7 @@ object Macro {
     import quotes.reflect._
     sc match {
       case '{ StringContext(${Varargs(parts)}: _*) } =>
-        for (part @ Const(s) <- parts)
+        for (part @ Unlifted(s) <- parts)
           report.error(s, Term.of(part).pos)
     }
     '{}