What version of ESLint are you using?
3.0.1
What rule do you want to change?
no-fallthrough
What code should be flagged as correct with this change?

/*eslint no-fallback: ["error", { "commentPattern": "[\\w\\s]*fallthrough" }]*/
var foo = ...;
switch(bar) {
    case 0: {
      if (typeof(foo) == 'string')
        return doSomething();
      // Otherwise, fallthrough
    }
    default:
      doSomethingElse();
}

What happens when the rule is applied to this code now?
Errors:
Expected a 'break' statement before 'default'.

... Basically I am asking for the rule to support case statements that contain braces.