What is an invalid expression?

ID:1620847
 
Jul 6 2014, 5:27 pm
(See the best response by LordAndrew.)
I've seen people asking what part of their code is generating this error.

I just want to know, in general what are the most common ways its generated and what is it.
Jul 6 2014, 5:45 pm
Best response
I did a quick check and it looks like invalid expression errors are caused when you have empty statement blocks, such as:

if (TRUE != FALSE)
    // If you don't put anything here, then it's an invalid expression.

// Or an empty one of these:

while (TRUE)