id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
13203	adjacent_filtered lets the first element entry through	Tony Lewis <tonyelewis@…>	Neil Groves	"`adjacent_filtered` always lets the first element of the range leak through, even for a predicate that rejects that element as either argument. Eg.

{{{
#!cpp
int main() {
	const std::vector<int> a = { 0, 1, 2, 3, 4, 5 };

	auto b = a | boost::adaptors::adjacent_filtered( [] (const int &x, const int &y) {
		return ( ( x > 2 ) && ( y > 2 ) );
	} );

	for (const auto &x : b) {
		std::cerr << x << ""\n"";
	}
}
}}}

…outputs:

{{{
0
4
5
}}}

From what I can see in the code, the predicate is currently only applied in the `increment()` function, which leaves it too late for the first element to be checked.
"	Bugs	new	To Be Determined	range	Boost Development Trunk	Problem		adjacent_filtered,adaptor,range,predicate,leak