Issues with `ref` local variables

The following snippet does not compile in the https://try.dot.net browser:

ref int Find(int[,] matrix, Func<int, bool> predicate)
{
    for (int i = 0; i < matrix.GetLength(0); i++)
        for (int j = 0; j < matrix.GetLength(1); j++)
            if (predicate(matrix[i, j]))
                return ref matrix[i, j];
    throw new InvalidOperationException("Not found");
}

int[,] sourceMatrix = new int[10, 10];
for (int x = 0; x < 10; x++)
    for (int y = 0; y < 10; y++)
        sourceMatrix[x, y] = x * 10 + y;

ref int item = ref Find(sourceMatrix, (val) => val == 42);
Console.WriteLine(item);
item = 24;
Console.WriteLine(sourceMatrix[4, 2]);

However, copying the ref return to a value does compile:

ref int Find(int[,] matrix, Func<int, bool> predicate)
{
    for (int i = 0; i < matrix.GetLength(0); i++)
        for (int j = 0; j < matrix.GetLength(1); j++)
            if (predicate(matrix[i, j]))
                return ref matrix[i, j];
    throw new InvalidOperationException("Not found");
}

int[,] sourceMatrix = new int[10, 10];
for (int x = 0; x < 10; x++)
    for (int y = 0; y < 10; y++)
        sourceMatrix[x, y] = x * 10 + y;

int item = Find(sourceMatrix, (val) => val == 42);
Console.WriteLine(item);
item = 24;
Console.WriteLine(sourceMatrix[4, 2]);

Note the difference in the 4th line from the end of the sample.

[jonsequitur]

In terms of which language features are supported, I’d suggest prototyping against https://try.dot.net?workspaceType=blazor-console.

For scaffolding, for now assume you’re executing inside Main. You’ll be able to customize the scaffolding soon, which we should meet to discuss.

[BillWagner]

Ahh. What’s the best way for me to work with you and your team to get a specific behavior on new content?

This is new content, so I have no preferred solution. I want to minimize extra work for all in creating new experiences.