Why does the ternary operator prevent Return-Value Optimization?

Question

Why does the ternary operator prevent Return-Value Optimization (RVO) in MSVC? Consider the following complete example program:

#include 

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Answer 1

I can see that it violates one general rule about RVO – that the return object (should) be defined at a single position.

The snippet below satisfies the rule:

Example e;
e = (i == 1)? Example{1} : Example{2};
return e;

But in the original expression like below, two Example objects are defined at two different positions according to MSVC:

return (i == 1) ? Example(1) : Example(2);

While the conversion between the two snippets is trivial to humans, I can imagine that it doesn't automatically happen in the compiler without a dedicated implementation. In other words, it's a corner case which is technically RVO-able but the devs didn't realize.