Missing parentheses around field assignment expression in list initializers

[mmusu3]

Input code

class AssignmentInCollectionInitializerTest
{
    int dataField;

    object Test()
    {
        return new int[] { dataField = 1 };
    }

    object Test2()
    {
        return new List<int> { (dataField = 1) };
        // Alternate syntax
        //return new List<int> { { dataField = 1 } };
    }

    object Test3()
    {
        return new Dictionary<int, int> { [0] = dataField = 1 };
    }

    object Test4()
    {
        return new Dictionary<int, int> { { 0, dataField = 1 } };
    }

    object Test5()
    {
        return new CustomCollection { (dataField = 1) };
        // Alternate syntax
        //return new CustomCollection { { dataField = 1 } };
    }

    class CustomCollection : IEnumerable<int>
    {
        public void Add(int value) { }
        public IEnumerator<int> GetEnumerator() => null;
        IEnumerator IEnumerable.GetEnumerator() => null;
    }
}

Erroneous output

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

internal class AssignmentInCollectionInitializerTest
{
	private int dataField;

	private object Test()
	{
		return new int[1] { dataField = 1 };
	}

	private object Test2()
	{
		// Error CS0117: 'List<int>' does not contain a definition for 'dataField'
		return new List<int> { dataField = 1 };
	}

	private object Test3()
	{
		return new Dictionary<int, int> { [0] = (dataField = 1) };
	}

	private object Test4()
	{
		return new Dictionary<int, int> { 
		{
			0,
			dataField = 1
		} };
	}

	private object Test5()
	{
		// Error CS0117: 'AssignmentInCollectionInitializerTest.CustomCollection' does not contain a definition for 'dataField'
		return new CustomCollection { dataField = 1 };
	}

	private class CustomCollection : IEnumerable<int>, IEnumerable
	{
		public void Add(int value)
		{
		}

		public IEnumerator<int> GetEnumerator()
		{
			return null;
		}

		IEnumerator IEnumerable.GetEnumerator()
		{
			return null;
		}
	}
}

Details

Tested at commit 587a359