Implement custom enumerator

Property	Value
Id	RR0210
Applicable Syntax	class that implements IEnumerable<T>
Syntax Span	identifier
Enabled by Default	✓

Usage

Example #1

before.cs

using System;
using System.Collections;
using System.Collections.Generic;

class C<T> : IEnumerable<T>
{
    IEnumerator<T> IEnumerable<T>.GetEnumerator()
    {
        throw new NotImplementedException();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        throw new NotImplementedException();
    }
}

after.cs

using System;
using System.Collections;
using System.Collections.Generic;

class C<T> : IEnumerable<T>
{
    IEnumerator<T> IEnumerable<T>.GetEnumerator()
    {
        throw new NotImplementedException();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        throw new NotImplementedException();
    }

    public Enumerator GetEnumerator()
    {
        return new Enumerator(this);
    }

    public struct Enumerator
    {
        private readonly C<T> _c;
        private int _index;

        internal Enumerator(C<T> c)
        {
            _c = c;
            _index = -1;
        }

        public T Current
        {
            get
            {
                throw new NotImplementedException();
            }
        }

        public bool MoveNext()
        {
            throw new NotImplementedException();
        }

        public void Reset()
        {
            _index = -1;
            throw new NotImplementedException();
        }

        public override bool Equals(object obj)
        {
            throw new NotSupportedException();
        }

        public override int GetHashCode()
        {
            throw new NotSupportedException();
        }
    }

    //TODO: IEnumerable.GetEnumerator() and IEnumerable<T>.GetEnumerator() should return instance of EnumeratorImpl.
    private class EnumeratorImpl : IEnumerator<T>
    {
        private Enumerator _e;

        internal EnumeratorImpl(C<T> c)
        {
            _e = new Enumerator(c);
        }

        public T Current
        {
            get
            {
                return _e.Current;
            }
        }

        object IEnumerator.Current
        {
            get
            {
                return _e.Current;
            }
        }

        public bool MoveNext()
        {
            return _e.MoveNext();
        }

        void IEnumerator.Reset()
        {
            _e.Reset();
        }

        void IDisposable.Dispose()
        {
        }
    }
}

Configuration

roslynator_refactoring.implement_custom_enumerator.enabled = true|false