How can I find all if-statements without an else?

I've got quite a lot of code in which sometimes if-statements have been written, without a matching else-statement. In some places, this is an issue, because when something fails, the failure is not handled correctly. I want to manually confirm all places an if-without-an-else occurs.

I've tried using regex, but I haven't succeeded in finding a way to match the right bracket, since regex cannot really handle nested brackets.

How can I list all these places, so I can go through them?