Allow for late initialization of names

Needed because we sometimes form NamedTypes with naked symbols.

Author: odersky

compiler/src/dotty/tools/dotc/core/Types.scala

@@ -1504,7 +1504,7 @@ object Types {
 
     def designatorName: Name = designator.asInstanceOf[Name] // ### todo: remove
 
-    private[dotc] def init()(implicit ctx: Context): this.type = {
+    private[dotc] def init(givenName: Name)(implicit ctx: Context): this.type = {
       (designator: Designator) match { // dotty shortcoming: need the upcast
         case DerivedName(underlying, info: SignedName.SignedInfo) =>
           myName = underlying.asInstanceOf[ThisName]
@@ -1513,8 +1513,7 @@ object Types {
         case designator: Name =>
           myName = designator.asInstanceOf[ThisName]
         case designator: Symbol =>
-          assert(designator.exists)
-          myName = designator.name.asInstanceOf[ThisName]
+          myName = givenName.asInstanceOf[ThisName]
           uncheckedSetSym(designator)
       }
       this

compiler/src/dotty/tools/dotc/core/Uniques.scala

@@ -58,7 +58,7 @@ object Uniques {
       def newType = {
         if (designator.isType) new CachedTypeRef(prefix, designator.asType, h)
         else new CachedTermRef(prefix, designator.asTerm, h)
-      }.init()
+      }.init(null)
       if (h == NotCached) newType
       else {
         val r = findPrevious(h, prefix, designator)
@@ -85,7 +85,7 @@ object Uniques {
       def newType = {
         if (name.isTypeName) new TypeRefWithFixedSym(prefix, name.asTypeName, sym.asInstanceOf[TypeSymbol], h)
         else new TermRefWithFixedSym(prefix, name.asTermName, sym.asInstanceOf[TermSymbol], h)
-      }.init()
+      }.init(name)
       if (h == NotCached) newType
       else {
         val r = findPrevious(h, prefix, sym)