Extract quote reification from Staging

compiler/src/dotty/tools/dotc/Compiler.scala

@@ -45,8 +45,9 @@ class Compiler {
 
   /** Phases dealing with TASTY tree pickling and unpickling */
   protected def picklerPhases: List[List[Phase]] =
+    List(new Staging) ::            // Check quotation levels (while healing types) and expand macros
     List(new Pickler) ::            // Generate TASTY info
-    List(new Staging) ::            // Expand macros and turn quoted trees into explicit run-time data structures
+    List(new ReifyQuotes) ::        // Turn quoted trees into explicit run-time data structures
     Nil
 
   /** Phases dealing with the transformation from pickled trees to backend trees */

compiler/src/dotty/tools/dotc/ast/TreeTypeMap.scala

@@ -162,7 +162,7 @@ class TreeTypeMap(
       assert(!to.exists(substFrom contains _))
       assert(!from.exists(newOwners contains _))
       assert(!to.exists(oldOwners contains _))
-      new TreeTypeMap(
+      newTreeTypeMap(
         typeMap,
         treeMap,
         from ++ oldOwners,
@@ -171,6 +171,11 @@ class TreeTypeMap(
         to ++ substTo)
     }
 
+  protected def newTreeTypeMap(typeMap: Type => Type, treeMap: tpd.Tree => tpd.Tree,
+      oldOwners: List[Symbol], newOwners: List[Symbol], substFrom: List[Symbol], substTo: List[Symbol]) = {
+    new TreeTypeMap(typeMap, treeMap, oldOwners, newOwners, substFrom, substTo)
+  }
+
   /** Apply `typeMap` and `ownerMap` to given symbols `syms`
    *  and return a treemap that contains the substitution
    *  between original and mapped symbols.

compiler/src/dotty/tools/dotc/quoted/TreeCleaner.scala

@@ -21,7 +21,7 @@ class TreeCleaner extends tpd.TreeMap {
 
   override def transform(tree: Tree)(implicit ctx: Context): Tree = {
     val tree0 = tree match {
-      case TypeDef(_, TypeBoundsTree(lo, hi)) if lo == hi =>
+      case TypeDef(_, TypeBoundsTree(lo, hi)) if lo.tpe =:= hi.tpe =>
         aliasesSyms = tree.symbol :: aliasesSyms
         aliasesTypes = lo.tpe :: aliasesTypes
         aliases(tree.symbol) = ref(lo.tpe.typeSymbol)

compiler/src/dotty/tools/dotc/tastyreflect/TreeOpsImpl.scala

@@ -775,7 +775,7 @@ trait TreeOpsImpl extends scala.tasty.reflect.TreeOps with CoreImpl with Helpers
         tpd.Return(expr, ctx.owner)
 
       def copy(original: Tree)(expr: Term)(implicit ctx: Context): Return =
-        tpd.cpy.Return(original)(expr, tpd.EmptyTree)
+        tpd.cpy.Return(original)(expr, tpd.ref(ctx.owner))
 
       def unapply(x: Term)(implicit ctx: Context): Option[Term] = x match {
         case x: tpd.Return => Some(x.expr)