Intellisense suggests switch expression on ref returns

[aalmada]

Version Used:
Visual Studio 2019 Version 16.5.0 Preview 1.0

Steps to Reproduce:

1. Add the following method:

public ref int GetItem(int[] array, int index)
{
    switch (index)
    {
        case 0: 
            return ref array[0];
        case 1:
            return ref array[0];
        default:
            return ref array[0];
    }
}

2. Apply the quick action convert switch statement to expression to the switch.

Expected Behavior:

Either, not suggest the action, if not possible, or convert to valid source code.

Actual Behavior:

Converts the method to

public ref int GetItem(int[] array, int index)
{
    return index switch
    {
        0 => ref array[0],
        1 => ref array[0],
        _ => ref array[0],
    };
}

resulting in the error error CS1525: Invalid expression term 'ref' for each case line.

[Rabadash8820]

I see two other related Issues that have already been closed: #42130 and #40198, which were marked closed after PR #40236 was merged.

However, correct me if I'm wrong @CyrusNajmabadi, but that PR doesn't actually make ref returns in switch expressions valid syntax, it just makes it so IntelliSense won't suggest that as a Quick Action. I personally think (as I think the openers of those other Issues would agree) that ref switches should be valid syntax, or at least, I don't see any reason why it shouldn't. Curious to hear if this is actually a planned addition to the language.

[CyrusNajmabadi]

Curious to hear if this is actually a planned addition to the language.

There is no plan to add that. If you would like that added, please make a feature request over at dotnet/csharplang. Thanks!

[Rabadash8820]

Just opened dotnet/csharplang#3326 👍