16.1.12 The Conditional Operator ? :

Suppose that b and c are expressions that are not boolean-valued.

• V is definitely assigned after a ? b : c iff both of the following are true:
  • V is definitely assigned after b.
  • V is definitely assigned after c.
• V is definitely assigned before a iff V is definitely assigned before a ? b : c.
• V is definitely assigned before b iff V is definitely assigned after a when true.
• V is definitely assigned before c iff V is definitely assigned after a when false.