setIntersection of struct range

[Jesse Phillips]

I am trying to obtain a rang that is the intersection of two other ranges. To do this I am using the _setIntersection()_ function.

    import std.algorithm;
    import std.stdio;

    struct S {
	string label;
    }

    void main() {
        auto s1 = new S[2];
        auto s2 = new S[2];

        s1[0].label = "fish";
        s1[1].label = "bar";
        s2[0].label = "foo";
        s2[1].label = "fish";

        foreach(str; setIntersection(s1,s2))
            writeln(str);
    }

The code above generates this error:

     C:\opt\dmd\windows\bin\..\..\src\phobos\std\functional.d(191):
          Error: static assert  "Bad binary function q{a < b}. 
             You need to use a valid D expression using symbols a of type S and b of type S."

So I attempted an intersection of string arrays, and received a different error. I'm not sure if I am at fault or the compiler. Shouldn't these work?

    import std.algorithm;
    import std.stdio;
    import std.array;

    struct S {
        string label;
    }

    void main() {
        auto s1 = ["fish", "bar"];
        auto s2 = ["foo", "fish"];

        foreach(str; setIntersection(s1,s2))
            writeln(str);
    }

Which ended up with:

    test.d(13): Error: template std.algorithm.setIntersection(alias less = "a < b",Rs...)
        if (allSatisfy!(isInputRange,Rs)) does not match any function template declaration
    test.d(13): Error: template std.algorithm.setIntersection(alias less = "a < b",Rs...)
        if (allSatisfy!(isInputRange,Rs)) cannot deduce template function from
        argument types !()(immutable(char)[][2u],immutable(char)[][2u])
    test.d(13): Error: foreach: int is not an aggregate type