/(?{"{"})/ # Check it outside of eval too
EXPECT
Sequence (?{...}) not terminated or not {}-balanced at - line 1, within pattern
-Sequence (?{...}) not terminated or not {}-balanced before HERE mark in regex m/(?{ << HERE "{"})/ at - line 1.
+Sequence (?{...}) not terminated or not {}-balanced in regex; marked by <-- HERE in m/(?{ <-- HERE "{"})/ at - line 1.
########
/(?{"{"}})/ # Check it outside of eval too
EXPECT