Fix problems handling case of bound type var in pickling

Author: odersky

compiler/src/dotty/tools/dotc/core/tasty/TastyFormat.scala

@@ -431,7 +431,8 @@ object TastyFormat {
        | ANNOTATEDtpt
        | ANDtpt
        | ORtpt
-       | BYNAMEtpt => true
+       | BYNAMEtpt
+       | BIND => true
     case _ => false
   }
 

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -249,6 +249,7 @@ class TreeUnpickler(reader: TastyReader, nameAtRef: NameRef => TermName, posUnpi
             case BIND =>
               val sym = ctx.newSymbol(ctx.owner, readName().toTypeName, BindDefinedType, readType())
               registerSym(start, sym)
+              if (currentAddr != end) readType()
               TypeRef.withFixedSym(NoPrefix, sym.name, sym)
             case POLYtype =>
               readMethodic(PolyType, _.toTypeName)