For this code, the compiler inlined the call. So there should be no difference between pass by copy or pass by reference, which is what was measured. Where it c

For this code, the compiler inlined the call. So there should be no difference between pass by copy or pass by reference, which is what was measured. Where it could matter is when the code isn’t inlined. But with small structs it might not matter all that much. It does sometimes matter though. One optimization I’ve seen in a few places is to box the error type, so that a result doesn’t copy the (usually empty) error by value on the stack. That actually makes a small performance difference, on the order of about 5-10%.