Since Symfony 5.4 release PHPUnit ends with exit code 1 if I start it with code coverage:

XDEBUG_MODE=coverage symfony php vendor/bin/simple-phpunit --coverage-text

the above command ends with the message:

Remaining indirect deprecation notices (1)

  1x: Method "PhpParser\NodeVisitor::enterNode()" might add "int|Node|null" as a native return type declaration in the future. Do the same in implementation "SebastianBergmann\CodeCoverage\StaticAnalysis\CodeUnitFindingVisitor" now to avoid errors or add an explicit @return annotation to suppress this message.
    1x in CodeCoverage::stop from SebastianBergmann\CodeCoverage

exit status 1

I believe this has the same reason as here: sebastianbergmann/php-file-iterator#74 (Document return type of Iterator::accept() so that Symfony's DebugClassLoader does not trigger a deprecation warning)

If I manually set a @return int|Node|null php doc comment for \SebastianBergmann\CodeCoverage\StaticAnalysis\CodeUnitFindingVisitor::enterNode phpunit will end without error.

Also if I add "symfony/error-handler": "<5.4" as require-dev dependency in composer.json, I do not experience an error.
This seems to be the only workaround I can do as end-user.

Suggested fix:
add correct return type php doc comment for the enterNode method. I assume it is null (is void and null the same?)