[Issue 17952] std.range.transposed save is invalid

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=17952

--- Comment #2 from Steven Schveighoffer <schveiguy at yahoo.com> ---
To ensure this test case is checking the right issue, change the third line to:

assert(y.equal([[1,4],[2,5],[3,6]]));

And get rid of the y.popFront.

Clearly, we should be able to iterate y without iterating x. But that's not
what happens (consuming any saved range consumes them all).

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