defensive coding of default action code: don't crash when the user action code chunks of the reduced rules leading up to the rule being resolved using the generated default action DO NOT track location info, while other user parts of the grammar DO track location, resulting in the default action code including default location tracking code, which would otherwise expect the rule terms to come with valid location info.
defensive coding of default action code: don't crash when the user action code chunks of the reduced rules leading up to the rule being resolved using the generated default action DO NOT track location info, while other user parts of the grammar DO track location, resulting in the default action code including default location tracking code, which would otherwise expect the rule terms to come with valid location info.

GerHobbelt/jison,GerHobbelt/jison,GerHobbelt/jison,GerHobbelt/jison