What steps can be taken to troubleshoot errors related to variable availability in anonymous functions in PHP?

When encountering errors related to variable availability in anonymous functions in PHP, ensure that the variables used inside the anonymous function are properly passed through the `use` keyword. This allows the anonymous function to access variables from the parent scope. Additionally, check for any typos or misspelled variable names that may be causing the issue.

// Incorrect way of using variables in an anonymous function
$var = 10;
$func = function() {
    echo $var; // This will cause an error
};
$func();

// Correct way of passing variables through the 'use' keyword
$var = 10;
$func = function() use ($var) {
    echo $var; // This will correctly access the variable
};
$func();