private bool MaybeAlreadyError <T>(NamedList <T> members, INamed named)
where T : class, INamedMember
{
if (members.ContainsKey(named))
{
var already = members[named].Name;
Errors.AtToken(ErrNo.Syntax001, named.Name, $"``{named.Name}´´ defined here ...");
Errors.AtToken(ErrNo.Syntax002, already, $"... is already defined here");
return(true);
}
return(false);
}