code: private Set<GinjectorBindings> getSourceGinjectors(Key<?> key) {
      Set<GinjectorBindings> sourceInjectors = new LinkedHashSet<GinjectorBindings>();
      for (Dependency dep : output.getGraph().getDependenciesOf(key)) {
        sourceInjectors.add(positions.get(dep.getTarget()));
      }
      return sourceInjectors;
    }
docs: Returns the injectors where the dependencies for node are currently placed.