pyflakes found 3 errors:

Lib/py_compile.py:200:20 undefined name 'quiet'
Lib/py_compile.py:204:20 undefined name 'quiet'
Lib/py_compile.py:213:20 undefined name 'quiet'

It seems like the code was introduced by PR 12976:

commit 2e33ecd7c9b0cac3efc6fcbdd4547fd086b4e2d1
Author: Joannah Nanjekye <33177550+nanjekyejoannah@users.noreply.github.com>
Date:   Tue May 28 13:29:04 2019 -0300

    bpo-22640: Add silent mode to py_compile.compile() (GH-12976)

Since bad input causes py_compile.py to issue an error like this:

  File "/usr/local/Cellar/python@3.8/3.8.3/Frameworks/Python.framework/Versions/3.8/lib/python3.8/py_compile.py", line 213, in main
    if quiet < 2:
NameError: name 'quiet' is not defined

I suggest, to save long review of a larger PR elsewhere, can we please just initially apply a patch like this:

[~/src/cpython(git:py_compile-quiet-not-initialised)]fleet2*> diff
+ exec git diff
diff --git a/Lib/py_compile.py b/Lib/py_compile.py
index 21736896af..cea851274d 100644
--- a/Lib/py_compile.py
+++ b/Lib/py_compile.py
@@ -186,6 +186,7 @@ def main(args=None):
     """
     if args is None:
         args = sys.argv[1:]
+    quiet = 0
     rv = 0
     if args == ['-']:
         while True:

Then the runtime issue goes away, and adding the feature fully can be addressed in a more leisurely fashion.

This is a duplicate of issue 38731. The inline patch in msg373791 is incorrect. I'll fix the error in maintenance releases by partially reverting commit 2e33ecd7c9b0cac3efc6fcbdd4547fd086b4e2d1.