Error installing on macOS arm64

[rockingh0rse]

Hi,
As the M1 hasn't been out long, just thought I'd mention this as it may not have been spotted yet:

Installation worked fine but got this error message right at the end...

/bin/bash: line 680: shell_profile: unbound variable
==> Next steps:
- Run `brew help` to get started

Regards,
Stuart

[SMillerDev]

Please create an issue in https://github.com/homebrew/install

[carlocab]

Opened a PR: Homebrew/install#521