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Changes between Initial Version and Version 1 of Ticket #12094, comment 1

initial	v1
1		It may be unintuitive, but it is not really a bug. Sequences (including expect operators in x3) may accept a tuple of container (e.g. string). If it gets a container, it expects its nodes to have an attribute of either a container, or the container's value type. See http://www.boost.org/doc/libs/1_60_0/libs/spirit/doc/html/spirit/qi/reference/operator/sequence.html
	1	It may be unintuitive, but it is not really a bug. Sequences (including expect operators in x3) may accept a tuple or container (e.g. string). If it gets a container, it expects its nodes to have an attribute of either a container, or the container's value type. See http://www.boost.org/doc/libs/1_60_0/libs/spirit/doc/html/spirit/qi/reference/operator/sequence.html
2	2
3	3	But what is the natural (inherent) attribute type of (r \| r)? It is a variant, not a container. That is why X3 got tripped. It can't handle the ambiguity. X3's attribute handling mechanism is not perfect. As it descends into the alternative, it already decided that it's attribute cannot handle the container, and thus tries to pass the element type of the container.