D-Programming-Language/phobos — pull request #901 by Poita (2012-10-27 10:57:12+00:00)
Title: Fix bug 8900 - Zip with infinite range fails.

`std.range.Zip` contains a `Tuple`, whose `toString()` function calls `formatElement` which eventually calls this function, leading to a static call to `walkLength` on infinite ranges. Since pull request 880, `walkLength` doesn't work with infinite ranges, so it fails to compile.

This change ensures that `walkLength` is called with only valid range types.

Bug: http://d.puremagic.com/issues/show_bug.cgi?id=8900