Reported by Phil Housley:

Throwing an error in a catch block acts as though you are still in the
try block.  Test case:

using GLib;

[ErrorDomain]
enum TestError {
        ERROR
}

class Test {

        public static void fail() throws TestError {
                throw new TestError.ERROR("");
        }

        public static void main(string[] args) {
                
                try {
                        fail();
                } catch (TestError ex) {
                        stdout.printf("Error caught\n");
                        fail();
                }
        }
}

This will loop forever, as each time the second "fail()" call is made,
the app will test the error condition, and loop back to the same goto
as the original catch.