# "$(...)" -- command substitution; not closing ")"
/\$([^)][^)]*)[^)]*$/bcheckchain
# multi-line "$(...\n...)" -- command substitution; treat as nested subshell
-/\$([ ]*$/bnest
+/\$([^)]*$/bnest
# "=(...)" -- Bash array assignment; not closing ")"
/=(/bcheckchain
# closing "...) &&"