anchor.diff:          'alias'!
           typeName
           typeParameters?
  -        satisfiedTypes?
           typeConstraints?
  -        ';'!
  +        aliasBody
  +    ;
  +
  +aliasBody
  +    : '='! type ';'!
       ;
   
   classDeclaration
  
positive.code:     :   'break'
      ;
  
  CHOICE
      :   'choice'
      ;
   
  CASE
      :   'case'
      ;
  
negative.code:     -> ^(ALIAS_DECL aliasDeclaration)
      | objectDeclaration
      -> ^(OBJECT_DECL objectDeclaration)
      ;
  
  importDeclaration
  