If I'm understanding this correctly (and that's a BIG "if"), then the "Eval-group ..." warning should not appear. 
$ perl -Mre=eval -e '/ (??{ "(?{1})" }) $_ /x'
Eval-group not allowed at runtime, use re 'eval' in regex m/(?{1})/ at
+ -e line 1.

[download]
It seems like the 'eval' hint doesn't reach the right scope at the right phase, but this is so out of my depth I'm getting the bends.

Brad

PS. These all work as I understand "use re qw/eval/" except the third: 

$ perl  -e '/ (?{1}) $_ /x'
Eval-group not allowed at runtime, use re 'eval' in regex m/ (?{1})  /
+ at -e line 1.

$ perl -Mre=eval -e '/ (?{1}) $_ /x'

# This is the odd one
$ perl -Mre=eval -e '/ (??{ "(?{1})" }) $_ /x'
Eval-group not allowed at runtime, use re 'eval' in regex m/(?{1})/ at
+ -e line 1.

$ perl -Mre=eval -e '/ (??{ qr"(?{1})" }) $_ /x'

[download]

In reply to Spurious re 'eval'; warning ? by bsb

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