SC2004 false positive on assignment to array position

[Matt Wilder]

For bugs

• Rule Id (if any, e.g. SC1000):
• My shellcheck version (shellcheck --version or "online"): 0.10.0, plus online
• The rule's wiki page does not already cover this (e.g. https://shellcheck.net/wiki/SC2086)
• I tried on https://www.shellcheck.net/ and verified that this is still a problem on the latest commit

Here's a snippet or screenshot that shows the problem:

NOTE: this is the simplest test case I could think of. Real world use case is more involved.

#!/bin/bash
declare -a foo=()
i=0
foo[$i]=bar
echo "${foo[@]}"

Here's what shellcheck currently says:

foo[$i]=bar
    ^-- SC2004 (style): $/${} is unnecessary on arithmetic variables.

Here's what I wanted or expected to see:

The checks should pass, as there is no arithmetic involved, nor is there a code syntax issue.

[Matt Wilder]

Nevermind, I did not realize $ wasn't necessary in arrays