If statements

For an if statement stmt of the form: if (expr) then-stmt else else-stmt v has the same definite assignment state at the beginning of expr as at the beginning of stmt. If v is definitely assigned at the end of expr, then it is definitely assigned on the control flow transfer to then-stmt and to either else-stmt or to the end-point of stmt if there is no else clause. If v has the state "definitely assigned after true expression" at the end of expr, then it is definitely assigned on the control flow transfer to then-stmt, and not definitely assigned on the control flow transfer to either else-stmt or to the end-point of stmt if there is no else clause. If v has the state "definitely assigned after false expression" at the end of expr, then it is definitely assigned on the control flow transfer to else-stmt, and not definitely assigned on the control flow transfer to then-stmt. It is definitely assigned at the end-point of stmt if and only if it is definitely assigned at the end-point of then-stmt. Otherwise, v is considered not definitely assigned on the control flow transfer to either the then-stmt or else-stmt, or to the end-point of stmt if there is no else clause.