Stacking from the same racial source

[Alex12]

In a campaign I'm playing in, a fellow player is asserting that the Aasimar alternate racial ability Deathless Spirit stacks with itself, so that if, for example, he were to have a necromancy spell cast on him that was a negative energy death effect, he would get a +6 bonus on the save: +2 against necromancy, +2 against negative energy, and +2 against death effects.
Something seems off about this to me, since it's all from the same source, but I know racial bonuses do stack, and the only potentially relevant instance in the PF rules (as opposed to 3.5 rules) I can find is that untyped bonuses from the same source don't stack. But this isn't untyped, it's a racial bonus. My gut says it should just be a +2 bonus, my friend and fellow player is saying it would (in the example above) be a +6 bonus.
I have a hard time imagining this or a similar situation hasn't come up before, but I can't find it.

[Gilarius]

You are correct, +2 it is. The other guy is being ingenuous.

Necromancy spell? +2 bonus.
Death effects? +2
Negative energy? +2.

Nothing says that those stack. However nothing explicitly says that they don't stack except the statement that stuff from the same source doesn't stack. All those plus 2s come from the same ability, therefore they don't stack.

[James Risner]

+1 to the "don't stack" crowd.

[Nefreet]

This question also comes up when a Dwarf is targeted with Poison.