anchor.diff:      node.safelyVisitChild(node.target, this);
     }
   
  -
  -
     //Dont visit identifiers in these AST nodes.
     visitLibraryDirective(LibraryDirective node) {}
     visitImportDirective(ImportDirective node) {}
     visitExportDirective(ExportDirective node) {}
     visitPartDirective(PartDirective node) {}
     visitPartOfDirective(PartOfDirective node) {}
  -
   }
positive.code:     }
    }
  
  
    //Only resolve the prefix.
    //TODO handle library 'as ...' imports.
    visitPrefixedIdentifier(PrefixedIdentifier node) {
  
negative.code:   Map<AstNode, Our.NamedElement> declaredElements;
    Map<Expression, Our.NamedElement> references = {};
    Map<String, Our.NamedElement> scope;
    
    Engine engine;
    Our.ClassElement _currentClass = null;
  
    ScopeVisitor(this.engine, this.declaredElements, this.references, this.library) {
      this.scope = {};
  