TYPO3 Core

Core: Exception handler (WEB): Uncaught TYPO3 Exception: #1476107295: PHP Catchable Fatal Error: Object of class PhpParser\Node\Expr\PropertyFetch could not be converted to string in /var/www/html/typo3/sysext/install/Classes/ExtensionScanner/Php/Matcher/ConstructorArgumentMatcher.php line 72 | TYPO3\CMS\Core\Error\Exception thrown in file /var/www/html/typo3/sysext/core/Classes/Error/ErrorHandler.php in line 130. Requested URL: https://typo3.ddev.site/typo3/install.php?install[controller]=upgrade&install[context]=backend    

• Install Introduction package
• Go to Admin Tool -> Upgrade -> Scan Extension Files
• Scan the "bootstrap_package" extension

One of the ajax requests for scanning the file will now throw the exception above in ConstructorArgumentMatcher for the following file:
typo3conf/ext/bootstrap_package/Contrib/scssphp/src/Compiler.php

see line 261 in Compiler.php:

$this->formatter = new $this->formatter();

The ConstructorArgumentMatcher fails to consider this dynamic way of resolving the className when instantiating the class.

Core: Exception handler (WEB): Uncaught TYPO3 Exception: #1476107295: PHP Catchable Fatal Error:
Object of class PhpParser\Node\Expr\PropertyFetch could not be converted to string in
typo3/sysext/install/Classes/ExtensionScanner/Php/Matcher/ConstructorArgumentMatcher.php line 72