How to undo not pushed deleted file ?

Recently I had to deal with a strange issue of IntelliJ when I've trying to move my Scala class to other package. The class looked like in the following snippet:

case class FirstCaseClass(....)
case class SecondCaseClass(....)
case class ThirdCaseClass(...)

Unfortunately, after moving the class in IntelliJ, instead of receiving 3 case classes in a single file, the 3 separate files were created. In such case the original file was marked as deleted and 3 new files were considered as "to add", similarly to the following snippet:

On branch master
Changes to be committed:
  (use "git reset HEAD ..." to unstage)

	deleted:    file1.txt

Untracked files:
  (use "git add ..." to include in what will be committed)

	file1_bis.txt

The first try to restore the file state to the state before changes was the use git checkout ${file_name} command. But it didn't work because the file was removed with git rm ${file_name} command:

bartosz:~/workspace/git_tests/undo_file_delete$ git checkout file1.txt
error: pathspec 'file1.txt' did not match any file(s) known to git.

To undo the file delete in Git we should begin by restoring the file status in the index:

bartosz:~/workspace/git_tests/undo_file_delete$ git reset -- file1.txt
Unstaged changes after reset:
D	file1.txt

Only at the end we can use the famous checkout command:

bartosz:~/workspace/git_tests/undo_file_delete$ git checkout file1.txt
bartosz:~/workspace/git_tests/undo_file_delete$ git status
On branch master
Untracked files:
  (use "git add ..." to include in what will be committed)

	file1_bis.txt

nothing added to commit but untracked files present (use "git add" to track)