import std.stdio;

import std.algorithm;

void main()

{

    auto records = [

        Record(10, 10),

        Record(12, 1),

        Record(30, 12),

        Record(10, 10),

        Record(12, 1)

    ];

    {

        // Works:

        auto groups = records.multiSort!(`a.x < b.x`).groupBy;

        writeln(groups);

    }

    {

        // Doesn't work:

        auto groups = records.multiSort!(`a.x < b.x`, `a.y < b.y`).groupBy;

        writeln(groups);

    }

}

​

struct Record

{

    int x;

    int y;

}