(foo|fool|x.|money|parted)$ fools n - -
(x.|foo|fool|x.|money|parted|y.)$ fools n - -
(foo|fool|money|parted)$ fools n - -
-(a|aa|aaa|aaaa|aaaaa|aaaaaa)(b|c) aaaaaaaaaaaaaaab y $1$2 aaaaaab
-(a|aa|aaa|aaaa|aaaaa|aaaaaa)(??{$1&&""})(b|c) aaaaaaaaaaaaaaab y $1$2 aaaaaab
+(a|aa|aaa||aaaa|aaaaa|aaaaaa)(b|c) aaaaaaaaaaaaaaab y $1$2 aaaaaab
+(a|aa|aaa||aaaa|aaaaa|aaaaaa)(??{$1&&""})(b|c) aaaaaaaaaaaaaaab y $1$2 aaaaaab
(a|aa|aaa|aaaa|aaaaa|aaaaaa)(??{$1&&"foo"})(b|c) aaaaaaaaaaaaaaab n - -
^(a*?)(?!(aa|aaaa)*$) aaaaaaaaaaaaaaaaaaaa y $1 a # [perl #34195]
^(a*?)(?!(aa|aaaa)*$)(?=a\z) aaaaaaaa y $1 aaaaaaa
^(a*?)(?!(a{6}|a{5})*$) aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa y $+[1] 12 # super-linear cache bug may return 18
^((?>(?:aa)?b)?) aab y $1 aab
^((?:aa)*)(?:X+((?:\d+|-)(?:X+(.+))?))?$ aaaaX5 y $1 aaaa
+X(A|B||C|D)Y XXXYYY y $& XY # Trie w/ NOTHING
+(?i:X([A]|[B]|y[Y]y|[D]|)Y) XXXYYYB y $& XY # Trie w/ NOTHING