Static Analysis You can use HipHop-PHP to do static analysis /tmp/hphp/files.txt $ hhvm --hphp -t analyze \ --input-list=/tmp/hphp/files.txt \ --include-path="/var/www/include" \ --output-dir=/tmp/hphp \ --gen-stats=1 \ --keep-tempdir=1 ]]> It will find these sorts of things Use of Undeclared Variables/Constants/Classes Calls to non-existent functions/methods Redefining constants Repeating a function parameter name in function declaration Required function parameters after optional ones in function declaration Too few/many arguments in a function call Code that will never be executed Use of Void return value Missing object context (using $this in a static method)