anchor.diff:  
   compilationUnit
       : importDeclaration*
  -      declaration+
  +      declarations
         EOF
       -> ^(IMPORT_LIST importDeclaration*)
  -       declaration+
  +       declarations
       ;
   
   typeDeclaration
  
positive.code:     ;
  
  specificationStatement
      : memberName specifier? ';'!
      ;
  
  expressionStatement
      : expression ';'!
      ;
  
  directiveStatement
  
negative.code:     ;
  
  memberParameters
      : typeParameters? formalParameters+ extraFormalParameters? metatypes? typeConstraints?
      ;
  
  //TODO: should we allow the shortcut style of method
  