WIP

Author: nicolasstucki

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

@@ -92,28 +92,19 @@ class Staging extends MacroTransformWithImplicits {
   override def run(implicit ctx: Context): Unit =
     if (ctx.compilationUnit.needsStaging) super.run
 
-  protected def newTransformer(implicit ctx: Context): Transformer =
-    new Reifier(new LevelInfo)
-
-  private class LevelInfo {
-    /** A map from locally defined symbols to the staging levels of their definitions */
-    val levelOf = new mutable.HashMap[Symbol, Int]
-  }
+  protected def newTransformer(implicit ctx: Context): Transformer = new Reifier()
 
   /** The main transformer class
    *  @param  level      the current level, where quotes add one and splices subtract one level.
    *                     The initial level is 0, a level `l` where `l > 0` implies code has been quoted `l` times
    *                     and `l == -1` is code inside a top level splice (in an inline method).
    *  @param  levels     a stacked map from symbols to the levels in which they were defined
    */
-  private class Reifier(levels: LevelInfo)
+  private class Reifier()
       extends ImplicitsTransformer {
-    import levels._
 
-    /** A nested reifier for a quote (if `isQuote = true`) or a splice (if not) */
-    def nested(isQuote: Boolean)(implicit ctx: Context): Reifier = {
-      new Reifier(levels)
-    }
+    /** A map from locally defined symbols to the staging levels of their definitions */
+    val levelOf = new mutable.HashMap[Symbol, Int]
 
     /** A stack of entered symbols, to be unwound after scope exit */
     var enteredSyms: List[Symbol] = Nil
@@ -278,12 +269,12 @@ class Staging extends MacroTransformWithImplicits {
     private def quotation(body: Tree, quote: Tree)(implicit ctx: Context): Tree = {
       val isType = quote.symbol eq defn.QuotedType_apply
       if (quotationLevel > 0) {
-        val body1 = nested(isQuote = true).transform(body)(quoteContext)
+        val body1 = transform(body)(quoteContext)
         // Keep quotes as trees to reduce pickled size and have a Expr.show without pickled quotes
         if (isType) ref(defn.QuotedType_apply).appliedToType(body1.tpe.widen)
         else ref(defn.QuotedExpr_apply).appliedToType(body1.tpe.widen).appliedTo(body1)
       } else {
-        val body1 = nested(isQuote = true).transform(body)(quoteContext)
+        val body1 = transform(body)(quoteContext)
         if (quotationLevel == 0 && !ctx.inInlineMethod) {
           quote match {
             case quote: Apply => cpy.Apply(quote)(quote.fun, body1 :: Nil)
@@ -303,7 +294,7 @@ class Staging extends MacroTransformWithImplicits {
      */
     private def splice(splice: Select)(implicit ctx: Context): Tree = {
       if (quotationLevel >= 1) {
-        val body1 = nested(isQuote = false).transform(splice.qualifier)(spliceContext)
+        val body1 = transform(splice.qualifier)(spliceContext)
         body1.select(splice.name)
       }
       else if (enclosingInlineds.nonEmpty) { // quotationLevel 0 in an inlined call
@@ -317,7 +308,7 @@ class Staging extends MacroTransformWithImplicits {
         splice
       }
       else if (Splicer.canBeSpliced(splice.qualifier)) { // quotationLevel 0 inside an inline definition
-        nested(isQuote = false).transform(splice.qualifier)(spliceContext) // Just check PCP
+        transform(splice.qualifier)(spliceContext) // Just check PCP
       }
       else { // quotationLevel 0 inside an inline definition
         ctx.error(