Anchor import symbols at current owner

Needed to harmonize behavior of Typer/Namer and tpd. This is needed
for making pickling, then unpickling the identity.

Author: odersky

src/dotty/tools/dotc/ast/tpd.scala

@@ -244,7 +244,7 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   }
 
   def Import(expr: Tree, selectors: List[untpd.Tree])(implicit ctx: Context): Import =
-    ta.assignType(untpd.Import(expr, selectors), ctx.newImportSymbol(expr))
+    ta.assignType(untpd.Import(expr, selectors), ctx.newImportSymbol(ctx.owner, expr))
 
   def PackageDef(pid: RefTree, stats: List[Tree])(implicit ctx: Context): PackageDef =
     ta.assignType(untpd.PackageDef(pid, stats), pid)

src/dotty/tools/dotc/core/Symbols.scala

@@ -228,8 +228,8 @@ trait Symbols { this: Context =>
     newSymbol(cls, nme.localDummyName(cls), EmptyFlags, NoType)
 
   /** Create an import symbol pointing back to given qualifier `expr`. */
-  def newImportSymbol(expr: Tree, coord: Coord = NoCoord) =
-    newSymbol(NoSymbol, nme.IMPORT, EmptyFlags, ImportType(expr), coord = coord)
+  def newImportSymbol(owner: Symbol, expr: Tree, coord: Coord = NoCoord) =
+    newSymbol(owner, nme.IMPORT, EmptyFlags, ImportType(expr), coord = coord)
 
   /** Create a class constructor symbol for given class `cls`. */
   def newConstructor(cls: ClassSymbol, flags: FlagSet, paramNames: List[TermName], paramTypes: List[Type], privateWithin: Symbol = NoSymbol, coord: Coord = NoCoord) =