id summary reporter owner description type status milestone component version severity resolution keywords cc 12473 Alternative parser inside permutation parser synthesizes uninitialized optional<> edaskel@… Joel de Guzman "In the process of developing a grammar I discovered a strange behavior where combining alternative and permutation parsers with attributeless parsers can result in invalid optional<> objects. For example, using ""eps"" as an example of an attributeless parser: {{{ ((int_ | eps) ^ eps) }}} is compatible with optional and compiles successfully, but if you parse an input where the int is not present, an uninitialized optional<> is produced - it acts as though it stored an int, but the value is uninitialized (32766, 32765, or 32764, on my system). The expression: {{{ (-int_ ^ eps) }}} also displays this behavior. I do have a workaround - using ''only'' the permutation parser works correctly. " Bugs closed To Be Determined spirit Boost 1.61.0 Problem fixed