roslyn: VS 16.1.3 - For To Foreach Bug CS1656

VS 16.1.3 converts this for:

void M(System.Collections.Generic.List<(string s1, string s2)> list)
{
    for (int i = 0; i < list. Count; i++)
    {
        list[i] = ("a", "b");
    }
}

To this foreach:

void M(System.Collections.Generic.List<(string s1, string s2)> list)
{
    foreach ((string s1, string s2) v in list)
    {
        v = ("a", "b");
    }
}

Which fails to compile with CS1656.

This issue has been moved from https://developercommunity.visualstudio.com/content/problem/608684/vs-1613-for-to-foreach-bug-cs1656.html VSTS ticketId: 919078 These are the original issue comments:

Visual Studio Feedback System on 6/17/2019, 01:46 AM (7 hours ago):

We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.

These are the original issue solutions: (no solutions)