How can I use the return value in a try/catch?

Question

I'm doing an external call in a try/catch block. This external call provides me with return value that I'll use further down the line.

However, I'm getting a TypeError: Try can only be used with external function calls and contract creation calls.

How can I use the values returned by the external call while in a try/catch?

Here the line:

uint256 x;
uint256 y;

try
    (x, y) = IVault(_vault).liquidate()
{
   // Do something
} catch {
   // Do something else
}

Answer 1

Ok, I found the issue: it's possible to manage the return value by using the returns keyword:

try
    IVault(_vault).liquidate() returns (uint256 _x, uint256 y)
{
   // Do something
} catch {
   // Do something else
}

Answer 2

You can use an ordinary if statement to check if the function call was successful