Invalid reference in compositor.cpp

Discovered by Clang.

compositor.cpp has the following piece of code.

struct FilterForVisibleRenderablesInRegion : public mc::FilterForRenderables
{
    FilterForVisibleRenderablesInRegion(mir::geometry::Rectangle enclosing_region)
        : enclosing_region(enclosing_region)
    {
    }
    bool operator()(mg::Renderable& renderable)
    {
        return !renderable.hidden();
    }
    mir::geometry::Rectangle &enclosing_region;
};

The struct member is a reference, but it is initialised to a constructor argument that is passed by value. When the constructor finishes the argument is destroyed and the reference becomes invalid.