[Issue 13122] std.algorithm.cartesianProduct output type immutability

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13122

--- Comment #1 from hsteoh at quickfur.ath.cx ---
Hmm. Isn't this expected behaviour? After all, typeof(a) == immutable(dchar)[],
so shouldn't the cartesianProduct result contain the same element type, i.e.,
immutable(dchar)?

--