std.algorithm.map + std.algorithm.joiner = broken forward range

[H. S. Teoh]

Code:
        import std.algorithm;
        import std.range;
        import std.stdio;

        void main() {
            auto x = [[1],[2],[3]];
            auto yy = x.map!"a".joiner;

            assert(isForwardRange!(typeof(yy)));
            writeln(yy.save);
            writeln(yy);
        }

Output:

        []
        [1, 2, 3]

:-(

That is to say, yy.save didn't save the range at all!


T
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