core/src/com/google/inject/internal/InjectorImpl.java
void index() {
    for (Binding<?> binding : state.getExplicitBindingsThisLevel().values()) {
      bindingsMultimap.put(binding.getKey().getTypeLiteral(), binding);
    }
  }
void index() {
    for (Binding<?> binding : state.getExplicitBindingsThisLevel().values()) {
      bindingsMultimap.put(binding.getKey().getTypeLiteral(), binding);
    }
  }
Indexes bindings by type.