Fix quoted type tags and use them instead of pickling

Author: nicolasstucki

compiler/src/dotty/tools/dotc/core/quoted/PickledQuotes.scala

@@ -121,13 +121,14 @@ object PickledQuotes {
   private def classTagToTypeTree(ct: ClassTag[_])(implicit ctx: Context): TypeTree = {
     val tpe = ct match {
       case ClassTag.Unit => defn.UnitType
+      case ClassTag.Boolean => defn.BooleanType
       case ClassTag.Byte => defn.ByteType
       case ClassTag.Char => defn.CharType
       case ClassTag.Short => defn.ShortType
       case ClassTag.Int => defn.IntType
       case ClassTag.Long => defn.LongType
       case ClassTag.Float => defn.FloatType
-      case ClassTag.Double => defn.FloatType
+      case ClassTag.Double => defn.DoubleType
     }
     TypeTree(tpe)
   }

compiler/src/dotty/tools/dotc/transform/ReifyQuotes.scala

@@ -352,6 +352,19 @@ class ReifyQuotes extends MacroTransformWithImplicits {
           liftList(splices, defn.AnyType))
       }
       if (splices.nonEmpty) pickleAsTasty()
+      else if (isType) {
+        def tag(tagName: String) = ref(defn.QuotedTypeModule).select(tagName.toTermName)
+        if (body.symbol == defn.UnitClass) tag("UnitTag")
+        else if (body.symbol == defn.BooleanClass) tag("BooleanTag")
+        else if (body.symbol == defn.ByteClass) tag("ByteTag")
+        else if (body.symbol == defn.CharClass) tag("CharTag")
+        else if (body.symbol == defn.ShortClass) tag("ShortTag")
+        else if (body.symbol == defn.IntClass) tag("IntTag")
+        else if (body.symbol == defn.LongClass) tag("LongTag")
+        else if (body.symbol == defn.FloatClass) tag("FloatTag")
+        else if (body.symbol == defn.DoubleClass) tag("DoubleTag")
+        else pickleAsTasty()
+      }
       else ReifyQuotes.toValue(body) match {
         case Some(value) => pickleAsValue(value)
         case _ => pickleAsTasty()

tests/run-with-compiler/quote-type-tags.check

@@ -0,0 +1,10 @@
+().asInstanceOf[Unit]
+true.asInstanceOf[Boolean]
+0.toByte.asInstanceOf[Byte]
+'a'.asInstanceOf[Char]
+1.toShort.asInstanceOf[Short]
+2.asInstanceOf[Int]
+3L.asInstanceOf[Long]
+4.0.asInstanceOf[Float]
+5.0.asInstanceOf[Double]
+5.0.asInstanceOf[Boolean]

tests/run-with-compiler/quote-type-tags.scala

@@ -0,0 +1,23 @@
+
+import dotty.tools.dotc.quoted.Toolbox._
+
+import scala.quoted._
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    def asof[T, U](x: Expr[T], t: Type[U]): Expr[U] =
+      '((~x).asInstanceOf[~t])
+
+    println(asof('(), '[Unit]).show)
+    println(asof('(true), '[Boolean]).show)
+    println(asof('(0.toByte), '[Byte]).show)
+    println(asof('( 'a' ), '[Char]).show)
+    println(asof('(1.toShort), '[Short]).show)
+    println(asof('(2), '[Int]).show)
+    println(asof('(3L), '[Long]).show)
+    println(asof('(4f), '[Float]).show)
+    println(asof('(5d), '[Double]).show)
+
+    println(asof('(5d), '[Boolean]).show) // Will clearly fail at runtime but the code can be generated
+  }
+}