NotNull<string> notNullStringValidator = "whatever"; //Ok
string x = notNullStringValidator; //Ok

notNullStringValidator.Equals(x); //true!

bool DoSomething(NotNull<string> @param)
{
    //@param is observed and validated when is instantiated. 
    //If validation fails no line of code will be run in this method

    Console.WriteLine("Whatever");
    
    //Gets @param value with no conversion
    return !string.IsNullOrWhiteSpace(@param); 
}

string p;

<Code where you can assign a value to p or not...>

var result = WhateverMethod(p);

<Continues if no exception was raised...>

namespace YourProject.Validators.Ranges.Int64
{
    internal class Neg100_1 : Range<Int64>
    {
        public override long Max => 1;

        public override long Min => -100;
    }
}

public void DoSometing(InRange<Neg100_1, Int64> param1) 
{
    ...
}

using Many.Validators.Clauses.S2;

public void DoSometing(All<NotNull<int?>, Positive<int?>, int?> param1) 
{
    ...
}

using Many.Validators.Clauses.S3;

public void DoSometing(All<NotNull<int?>, Positive<int?>, InRange<Int_1_100, int?>, int?> param1) 
{
    ...
}

class YourObject
{
    public string Id {get;set;}
    public string Data {get;set;}
}

public void DoSomething(NotNull<YourObject> param) //This line checks if param itself is not null
{
    var otherParamsToCheck = new string[]{param.Id, param.Data};

    //You can validate params and get an exception if any of them is not valid or...
    NotNull<string>.Validate(otherParamsToCheck);

    //...you can validate params and get the whole result with no exceptions

    //1.Get all errors
    var result = NotNull<string>.IsValid(otherParamsToCheck, out string[] errors);

    //2.Get and stop after first error
    result = NotNull<string>.IsValid(otherParamsToCheck, out string error);    
}