Marcel Taeumel uploaded a new version of Regex-Tests-Core to project The Trunk:
http://source.squeak.org/trunk/Regex-Tests-Core-ct.14.mcz

==================== Summary ====================

Name: Regex-Tests-Core-ct.14
Author: ct
Time: 8 July 2021, 12:52:32.198695 am
UUID: 7fc43ad7-9987-9f48-aee8-07498df21307
Ancestors: Regex-Tests-Core-ct.13

Adds another regression test for lookbehinds in nullable closures. This one is more serious; it raises a nil MNU because the marker chain is defect.

Just adding this for now as a known bug, I don't have the resources to fix this right now. But if no one else is keen on this, I will probably give this another try in my next holidays ... :-)

=============== Diff against Regex-Tests-Core-ct.12 ===============

Item was added:
+ ----- Method: RxParserTest>>testOptionalLookbehind (in category 'tests') -----
+ testOptionalLookbehind
+ 
+ 	self assert: ['A' matchesRegex: '((?<=^)A)+'].
+ 	
+ 	self assert: [('AB' allRegexMatches: '((?<=a)b)?') asArray = #('A')].!