How to reproduction:
Step 1: make bad source code
Step 2: run "python -m py_compile bad_source_code.py"
Step 3: errors printed

It seems that this problem is introduced at issue 22640 (commit https://github.com/python/cpython/commit/2e33ecd7c9b0cac3efc6fcbdd4547fd086b4e2d1)
and it have not fixed yet.

variable 'quiet' is not defined in main function as far as I can see.

```
Traceback (most recent call last):
  File "c:\users\<USERNAME>\.scoop\apps\python\3.8.0\Lib\py_compile.py", line 144, in compile
    code = loader.source_to_code(source_bytes, dfile or file,
  File "<frozen importlib._bootstrap_external>", line 846, in source_to_code
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "c:/Users/<USERNAME>/AppData/Local/Temp/flycheckrIYLj4/test.py", line 25
    def calc_entropy(self):
    ^
IndentationError: expected an indented block

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\users\<USERNAME>\.scoop\apps\python\3.8.0\Lib\py_compile.py", line 209, in main
    compile(filename, doraise=True)
  File "c:\users\<USERNAME>\.scoop\apps\python\3.8.0\Lib\py_compile.py", line 150, in compile
    raise py_exc
__main__.PyCompileError: Sorry: IndentationError: expected an indented block (c:/Users/<USERNAME>/AppData/Local/Temp/flycheckrIYLj4/test.py, line 25)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\users\<USERNAME>\.scoop\apps\python\3.8.0\Lib\runpy.py", line 192, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "c:\users\<USERNAME>\.scoop\apps\python\3.8.0\Lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "c:\users\<USERNAME>\.scoop\apps\python\3.8.0\Lib\py_compile.py", line 218, in <module>
    sys.exit(main())
  File "c:\users\<USERNAME>\.scoop\apps\python\3.8.0\Lib\py_compile.py", line 213, in main
    if quiet < 2:
NameError: name 'quiet' is not defined

```

New changeset 98f0f04b5016e63561d313a3446b7b58f2c12611 by Pablo Galindo (Batuhan Taşkaya) in branch 'master':
bpo-38731: Fix function signature of quiet in docs (GH-17719)
https://github.com/python/cpython/commit/98f0f04b5016e63561d313a3446b7b58f2c12611

New changeset 04c1efe5acc89b6f3f2c208604a1c35641e8a380 by Miss Islington (bot) in branch '3.8':
bpo-38731: Fix function signature of quiet in docs (GH-17719)
https://github.com/python/cpython/commit/04c1efe5acc89b6f3f2c208604a1c35641e8a380

The bug is still there in python 3.8.4rc1
It has nothing to do with the doc.

As pointed by Kaoru, it is introduced in line 200 of commit 2e33ecd7c9b0cac3efc6fcbdd4547fd086b4e2d1

see this comment, also by Kaoru:
https://github.com/python/cpython/commit/2e33ecd7c9b0cac3efc6fcbdd4547fd086b4e2d1#r35842880

The regression is tracked here: https://bugs.python.org/issue40456

And a PR is under review here: https://github.com/python/cpython/pull/17134

Also, this issue is a duplicate to this: https://bugs.python.org/issue40456

One of these should be closed.

Thanks Joannah, I confirm this is a duplicate of https://bugs.python.org/issue40456

The issue is better tracked in 40456, so you can close here.

New changeset daff39070e7ea71b0ba49d9150ac7a210a125682 by Gregory Schevchenko in branch 'master':
bpo-38731: Add --quiet option to py_compile CLI (GH-17134)
https://github.com/python/cpython/commit/daff39070e7ea71b0ba49d9150ac7a210a125682

New changeset 2024d7aca100c3faa9c6730aba3de5f0528750be by Berker Peksag in branch '3.9':
bpo-38731: Fix NameError in command-line interface of py_compile (GH-21617)
https://github.com/python/cpython/commit/2024d7aca100c3faa9c6730aba3de5f0528750be

New changeset 949cf93f8ee27c37650483458f0aa3e295011ef6 by Miss Islington (bot) in branch '3.8':
bpo-38731: Fix NameError in command-line interface of py_compile (GH-21617)
https://github.com/python/cpython/commit/949cf93f8ee27c37650483458f0aa3e295011ef6