a No exception b Uncaught exception Backtrace2.Error("b") Raised at file "backtrace2.ml", line 18, characters 21-32 Called from file "backtrace2.ml", line 18, characters 42-53 Called from file "backtrace2.ml", line 18, characters 42-53 Called from file "backtrace2.ml", line 18, characters 42-53 Called from file "backtrace2.ml", line 18, characters 42-53 Called from file "backtrace2.ml", line 18, characters 42-53 Called from file "backtrace2.ml", line 22, characters 4-11 Re-raised at file "backtrace2.ml", line 24, characters 68-71 Called from file "backtrace2.ml", line 29, characters 11-23 Uncaught exception Backtrace2.Error("c") Raised at file "backtrace2.ml", line 25, characters 26-37 Called from file "backtrace2.ml", line 29, characters 11-23 Uncaught exception Backtrace2.Error("d") Raised at file "backtrace2.ml", line 18, characters 21-32 Called from file "backtrace2.ml", line 18, characters 42-53 Called from file "backtrace2.ml", line 18, characters 42-53 Called from file "backtrace2.ml", line 18, characters 42-53 Called from file "backtrace2.ml", line 18, characters 42-53 Called from file "backtrace2.ml", line 18, characters 42-53 Called from file "backtrace2.ml", line 22, characters 4-11 Called from file "backtrace2.ml", line 29, characters 11-23 Uncaught exception Invalid_argument("index out of bounds") Raised by primitive operation at file "backtrace2.ml", line 29, characters 14-22