More D newb questions.

[Walter Bright]

Steven Schveighoffer wrote:
> You are concatenating the struct contents, into a new array.  I don't see 
> the ambiguity or the confusion it would cause.

If S is a container type, there is a huge difference between creating an 
array of two of those containers, and creating a new container that 
concatenates the contents of those two containers.

There is no way opCat can do both jobs.