Evaluate annotations before completing tree of definitions

Motive: That way we can identify annotation macros without special
name resolution rules.

This was surprisingly easy.

Author: odersky

src/dotty/tools/dotc/typer/Namer.scala

@@ -562,8 +562,8 @@ class Namer { typer: Typer =>
      *  to pick up the context at the point where the completer was created.
      */
     def completeInCreationContext(denot: SymDenotation): Unit = {
-      denot.info = typeSig(denot.symbol)
       addAnnotations(denot)
+      denot.info = typeSig(denot.symbol)
       Checking.checkWellFormed(denot.symbol)
     }
   }