[Syntax rule] Now you can throw and catch only int values It was possible to throw scalar expressions like strings and dates, such as throw "hello world";, and get no compile error. At runtime this was catch-able by a catch block that was not decorated with any specific value, such as catch {print("Catch worked.");}. Now the only expression you can put on the throw keyword is an int. Often the best thing to throw is Global::error("Explanation");. Often the best thing to catch is an element of the Exception enum. For more information, see Exception Handling with try and catch Keywords. [Area] 
Exceptions
E s c a p e
E x c e p t i o n s
I n h e r i t a n c e
I n t e r f a c e s
M o d i f i e r s
P a r a m e t e r s
P r e p r o c e s s o r