+ '/(?\ix/' => 'Sequence (?\...) not recognized in regex; marked by {#} in m/(?\{#}ix/',
+ '/(?\mx/' => 'Sequence (?\...) not recognized in regex; marked by {#} in m/(?\{#}mx/',
+ '/(?\:x/' => 'Sequence (?\...) not recognized in regex; marked by {#} in m/(?\{#}:x/',
+ '/(?\=x/' => 'Sequence (?\...) not recognized in regex; marked by {#} in m/(?\{#}=x/',
+ '/(?\!x/' => 'Sequence (?\...) not recognized in regex; marked by {#} in m/(?\{#}!x/',
+ '/(?\<=x/' => 'Sequence (?\...) not recognized in regex; marked by {#} in m/(?\{#}<=x/',
+ '/(?\<!x/' => 'Sequence (?\...) not recognized in regex; marked by {#} in m/(?\{#}<!x/',
+ '/(?\>x/' => 'Sequence (?\...) not recognized in regex; marked by {#} in m/(?\{#}>x/',