Ошибка CS7002: неожиданное использование универсального имени

MainPack<T> mainPack<T> = new MainPack<T>();

private Dictionary<Type, object> mainPack = new Dictionary<Type, object>{ { typeof(Word), new MainPack<Word>() }, { typeof(byte), new MainPack<byte>() } };
private MainPack<T> MainPack_<T>{ get => (T)mainPack[typeof(T)]; set => mainPack[typeof(T)] = value; }

private Dictionary<Type, object> mainPack = new Dictionary<Type, object>{ { typeof(Word), new MainPack<Word>() }, { typeof(byte), new MainPack<byte>() } };

[DebuggerDisplay("({string_}, {space})")]
public class Word
{
    public string string_;
    public bool space;
 
    public Word()
    {
        string_ = "";
        space = false;
    }
 
    public Word(string new_string, bool new_space)
    {
        string_ = new_string;
        space = new_space;
    }
 
    public override bool Equals(object obj)
    {
        if (obj == null)
        {
            return false;
        }
        Word m = obj as Word;
        if (m == null as Word)
        {
            return false;
        }
        return (string_ == m.string_);
    }
 
    public override int GetHashCode()
    {
        return string_.GetHashCode() ^ space.GetHashCode();
    }
 
    public static bool operator ==(Word _Left, Word _Right)
    {
        return (!(_Right is null) && _Left.string_ == _Right.string_ && _Left.space == _Right.space);
    }
 
    public static bool operator !=(Word _Left, Word _Right)
    {
        return !(_Left == _Right);
    }
}

    [DebuggerDisplay("({Word}, {IsSpace})")]
    public class WordSpace : IEqualityComparer, IEquatable<WordSpace>, IEqualityComparer<WordSpace>
    {
        public string Word { get; }
        public bool IsSpace { get; }
        public int HashCode { get; }
 
        public WordSpace(string word, bool isSpace)
        {
            Word = word ?? "";
            IsSpace = isSpace;
            HashCode = Word.GetHashCode() ^ IsSpace.GetHashCode();
        }
 
        public override bool Equals(object obj)
            => obj is WordSpace wordSpace
            && Equals(wordSpace);
 
        public override int GetHashCode() => HashCode;
 
        public new bool Equals(object x, object y)
            => x!=null && x.Equals(y);
 
        public int GetHashCode(object obj)
            => obj is WordSpace  wordSpace
            ? wordSpace.HashCode
            : obj.GetHashCode();
 
        public bool Equals(WordSpace other)
            => Equals(this, other);
 
        public bool Equals(WordSpace x, WordSpace y)
            => x.HashCode == y.HashCode
            && x.IsSpace == y.IsSpace
            && x.Word == y.Word;
 
        public int GetHashCode(WordSpace wordSpace)
            => wordSpace.HashCode;
 
    }