SC2086: Numeric expansion

[aeiplatform]

For bugs

• Rule Id: SC2086
• My shellcheck version: 0.9.0
• [x] The rule's wiki page does not already cover this at Wiki
• [x] I tried on shellcheck.net and verified that this is still a problem on the latest commit

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

#!/bin/sh
a=hey
b=${#a}
echo $b ${#a}

Here's what shellcheck currently says:

Line 4:
echo $b ${#a}
     ^-- SC2086 (info): Double quote to prevent globbing and word splitting.

Here's what I wanted or expected to see:

Nothing. Expansion is always numeric length.

[aeiplatform]

This rule should behave same like int constant assignment.

b=3
b=${#a}