[pcre-dev] Regression: Lookbehind assertions with fixed numb…

I am reporting a regression related to look*behind* assertions which
contain a fixed number of repetitions. PCRE no longer recognizes them as
fixed length and reports a compile error.

The following simple positive and negative lookbehind assertion examples
fail with the current version (8.20 and SVN 743). The error message is
"lookbehind assertion is not fixed length":

(?<=a{2})b
(?<!a{2})b

Both patterns worked fine in PCRE 8.11. As far as I can tell, the
problem was introduced somewhere between SVN 582 and SVN 606.

Can you reproduce the problem? Any suggestions how to fix this would be
very welcome!

Ralf

PS: Not sure if this matters, but look*ahead* assertions work fine and
seem unrelated to the problem.