Many false positives

[JeroenDeDauw]

I've been trying out Humbug on several of my projects. A significant amount of the mutations that are reported as survived do not actually survive if I make them manually and then run the tests. I've not been able to pin this down to any specific thing. This happens for different types of mutations in different types of code.

Seeing this in a PHP 5.5 codebase when running the tool with PHP 7.0 and in a PHP 7.1 codebase when running with PHP 7.1.

For instance occurs for this PHP library: https://github.com/wmde/WikibaseDataModel (some of the remaining mutations there actually do survive for real but are harmless)

[JeroenDeDauw]

This is with Humbug 1.0-dev 06b1c05 Mon Aug 1 11:27:00 2016 +0100