[Issue 16251] regex - `(..).*\1` doesn't match "axxxx"

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16251

--- Comment #5 from Vladimir Panteleev <thecybershadow at gmail.com> ---
There are some backreference tests here:

https://github.com/dlang/phobos/blob/master/std/regex/internal/tests.d#L310-L315

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