如何在Bash中捕获错误坏数组下标

Question

此代码段会产生两个错误：＆＃34;找不到命令＆＃34;被陷阱困住的＆＃34;坏数组下标＆＃34;那不是。有没有办法陷阱＆＃34;坏数组下标？＆＃34;

运行Bash版本4.4

shopt -s extdebug  # Necessary after 4.3 for trapping in functions
set -o pipefail
set -o errtrace

error() {
    echo "There was an error at line $1"
}
trap 'error ${LINENO}' ERR

declare -A arr
foo=''
# Next line generates one error:
# -bash: arr: bad array subscript  # this error is not trapped
"${arr[$foo]-echo}"

# Next line generates two errors:
# -bash: arr: bad array subscript  # this error is not trapped
# -bash: : command not found  # this error is trapped
"${arr[$foo]}"
: