Default case in the middle of a switch doesn't fallthrough correctly

[ykagan]

Simple example here:
function foo(bar) { switch (bar) { case 'a': return 1; case 'b': default: return 2; case 'c': return 3; } }

This results in incorrect output:

function foo(a){return'a'===a?1:'b'===a||'c'===a?3:2}

where 'b' returns 3 instead of 2. It looks like babili fails to detect that 'b' should fallthrough to the default case when it converts the switch statement into a conditional.