https://issues.dlang.org/show_bug.cgi?id=18426
--- Comment #2 from Seb <greensunn...@gmail.com> --- And a stripped down version of std.typecons.Tuple: https://gist.github.com/wilzbach/0a55a571f1c46e9d59420cf158354b85 > A better implementation would be to have the Tuple with named fields use the > Tuple with no named fields as its only member variable; then, "alias this" > needs to simply return a reference to that member. This is already done: struct Tuple { Types expand; // e.g. AliasSeq!(int, int) } However, if `alias expand this` is used, this stops to work: --- auto t1 = Tuple!(int, "x", string, "y")(1, "a"); void foo(Tuple!(int, string) t2) {} foo(t1); --- foo.d(149): Error: function foo.__unittest_L143_C7.foo(Tuple!(int, string) t2) is not callable using argument types (Tuple!(int, "x", string, "y")) foo.d(149): cannot pass argument t1 of type Tuple!(int, "x", string, "y") to parameter Tuple!(int, string) t2 --
