Shellcheck does not issue unused variable error when local variable shadows global

For bugs

• Rule Id (if any, e.g. SC1000):
• My shellcheck version (shellcheck --version or 'online'): online
• I tried on shellcheck.net and verified that this is still a problem on the latest commit
• It's not reproducible on shellcheck.net, but I think that's because it's an OS, configuration or encoding issue

For new checks and feature suggestions

• shellcheck.net (i.e. the latest commit) currently gives no useful warnings about this
• I searched through https://github.com/koalaman/shellcheck/issues and didn't find anything related

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

#!/bin/bash

function func
{
    local var=inner
}

var=outer
func
echo $var

Here's what shellcheck currently says:

No issues detected

Here's what I wanted or expected to see:

the local var=inner line has no effect; it should generate an SC2034 or similar. Shellcheck sees var is read in the outer scope, but doesnʼt notice that the one inside func isnʼt talking about the same variable.