local variable declaration blocks a warning about unassigned global variable with the same name

[AleXoundOS]

For bugs

• Rule Id: SC2154
• My shellcheck version: online
• [x] 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

• [x] shellcheck.net (i.e. the latest commit) currently gives no useful warnings about this
• [x] 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:

#! /usr/bin/env bash

func1() {
  echo "$myvar"
}

func2() {
  local myvar=""
}

func1
func2

Here's what shellcheck currently says:

$ shellcheck myscript
No issues detected!

Here's what I wanted or expected to see:

$myvar in func1 is referenced but not assigned.

If executed using bash -u test.sh:

/tmp/test.sh: line 4: myvar: unbound variable

[sseypt]

Same here.