If a function has an error type (indicated by a ! in the return type), you have a few options. You can use `result = try foo();`, which will propagate the error out of the function (which now must have ! in its signature). Or you can use `result = foo() catch default;` or `result = foo() catch unreachable;`. The former substitutes a default value, the latter is undefined behavior if there's an error (panic, in debug and ReleaseSafe modes).

Or, just `result = foo();` gives `result` an error-union type, of the intended result or the error. To do anything useful with that you have to unwrap it with an if statement.

It's a different, simpler mechanism, with much less impact on performance, and (my opinion) more likely to end up with correct code. If you want to propagate errors the way exceptions do, every function call needs a `try` and every return value needs a ! in the return type. Sometimes that's what you need, but normally error propagation is shallow, and ends at the first call which can plausibly do anything about the error.