id	summary	reporter	owner	description	type	status	priority	component	version	resolution	keywords	cc
237	Various container includes cannot be in the same compile unit	mlbrooks	Michael Brooks <mlbrooks@…>	"Known inconsistencies:
- Vector with bits/Containers
- Vector with bits/Sequence

Minimal case
{{{
#include <vector.hfa>
#include <bits/sequence.hfa>
}}}
Expected: compile succeeds; link fails (no main)
Actual: compile fails: Cannot choose between 2 alternatives for `back = 0p` in `?{}( Sequable & )`, where `back` is ambiguous between datum `sq.back` (intended) and function declared in vector.hfa (unintended).

Applied case
{{{
#include <vector.hfa>             // as in tests/vector.cfa
#include <bits/weakso_locks.hfa>  // represents desire to add this include in fstream.hfa
#include <fstream.hfa>            // as in tests/vector.cfa
}}}
(Behaviours are similar)

These prevent Fstream from including Locks (which includes both the above bits) because the Vector test includes Fstream, which produces the problem combination.

Problem comes from bits/x shipping function bodies that declare and refer to the names front/back.  When included in a clean context, those names resolve as intended.  When included in a context that already has Vector, those names conflict with declarations from Vector, making the lookups ambiguous.  The uses that suffer from the ambiguity have assignment/comparison with very generic other arguments, e.g. `front != 0p`.
"	defect	closed	minor	libcfa	1.0	fixed