Fix "Warning! PATH is not properly set up..." when running "rvm use 2.7.0 --default"

I ran rvm use 2.7.0 --default to switch to ruby 2.7.0

But ran into this error:

Warning! PATH is not properly set up, /home/tao/.rvm/gems/ruby-2.6.1/bin is not at first place.
Usually this is caused by shell initialization files. Search for PATH=... entries.
You can also re-add RVM to your profile by running: rvm get stable --auto-dotfiles
To fix it temporarily in this shell session run: rvm use ruby-2.6.1
To ignore this error add rvm_silence_path_mismatch_check_flag=1 to your ~/.rvmrc file.

Here's how to fix it, add rvm_silence_path_mismatch_check_flag=1 to your ~/.rvmrc file.

Now when running the command you will get:

// ♥ rvm use 2.7.0 --default

RVM is not a function, selecting rubies with 'rvm use ...' will not work.

You need to change your terminal emulator preferences to allow login shell.
Sometimes it is required to use /bin/bash --login as the command.
Please visit https://rvm.io/integration/gnome-terminal/ for an example.

To permanently fix the second error:

Add this into your VSCode settings.json file:

// Linux
"terminal.integrated.shellArgs.linux": ["-l"]

Source for the permanent fix: https://code.visualstudio.com/docs/editor/integrated-terminal

OR

Run: /bin/bash --login

Now rvm use 2.7.0 --default should work, and return the message:

Using /home/tao/.rvm/gems/ruby-2.7.0