opening a pipe to a while read loop flags assignment of $? as SC2319

[solstice333]

Min repro:

#!/usr/bin/env bash

while read line; do
    rev=$line

    [[ "${rev#foo}" == "$rev" ]]
    is_foo=$?   # This $? refers to a condition, not a command. Assign to a variable to avoid it being overwritten. See SC2319.

    echo "$rev: $is_foo"
done < $TEMP/foo.lst | sort

where is_foo=$? is flagged with SC2319. The expectation is for this line not to be flagged bc $? is being assigned.

Removing the pipe of while read ... to sort causes the SC2319 warning to disappear:

#!/usr/bin/env bash

while read line; do
    rev=$line

    [[ "${rev#foo}" == "$rev" ]]
    is_foo=$?

    echo "$rev: $is_foo"
done < $TEMP/foo.lst