Added Annotation for custom tracking methods

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Prerequisites

• [x] I have written a descriptive issue title
• [x] I have verified that I am running the latest version of DisposableFixer: YOUR_VERSION
• [x] I have searched open and closed issues to ensure it has not already been reported

Description

In order to detect possible NullReferencesExceptions, JetBrains implemented some attributes within JetBrains.Annotations, so that everybody can mark their custom methods with attributes like CanBeNull. Something like that can be useful, too.

IgnoreMethodDuringDisposeDetectionAttribute

• ca be allied to classed and methods
• marks a method that should be ignored during dispose detection.

IgnoreClassDuringDisposeDetectionAttribute

• ca be allied to classed and methods
• Used for classes that implements IDisposable, but there is no need to dispose it,

TrackingMethodAttribute

• can be applied to methods
• defines that a method keeps track of IDisposable given via parameters
• has optional parameter like: third parameter should be true

CallsDisposeAttribute

• can be applied to methods
• if this method was called, instance should be considered as disposed. Example

internal class Usage{
   public Usage(){
      var instance = new SomeSpecialClass() //this is not marked as undisposed, because Cleanup is called
      instance.Cleanup(); 
   }
}
internal class SomeSpecialClass : IDisposeable{
   [CallsDispose]
   public void Cleanup(){
      
   }
   public void Dispose(){
   }
}

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New version

Attribute	Description	Target
Piped	Defines that return value it that marked argument. Only on per argument in signature is allowed to be marked with this attribute	Argument
Tracked	On a Argument, it defined that the argument will get tracked by the method; On a ReturnValue, it defines that the return value is tracked by the method	Argument or ReturnValue
TrackedSet	Show file differences that haven't been staged	Property
DisposeCall	Defines that method is equivalent to a Dispose method	Method

Piped

Often fluent APIs use this pattern to configure a object wit (extension) method. In order to allow the callee to detect such a pattern, the Argument that is used an input an output can be marked with this attribute.

Example:

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We need an additional attribute to mark an setter as Safe during ObjectInitialization. E.g.

using System.Net;
using System.Net.Http;

namespace SomeNamespace
{
    internal class HttpResponseMessageSpec
    {
        public HttpResponseMessage CreateResponse1()
        {
            var msg = new HttpResponseMessage(HttpStatusCode.Accepted)
            {
                /* This should not yield an error because this is initialization and we Content if null after ctor was called. */
                Content = new StringContent("some content")
            };
            
            return msg;
        }
    }
}

There should be a Attribute that marks Content in order to signal, that Content is Null after ctor of HttpResponseMessage was called. Therefore the first set to Content with an IDisposable is allowed, We can modify TrackedSet. It can have a mode Always or Once. In order to simplify the code, a property marked with TrackedSet(Once) could only be set when using object initializer.

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When DisposeCallAttribute is put on an interface method, the implementations and overrides should be treated as dispose calls as well

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Checkout this https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/attributes/