How was the original statement perfectly valid? Let's try with two different compilers: gcc 8.2: https://godbolt.org/z/ZcsChr https://godbolt.org/z/ZcsChr cla

How was the original statement perfectly valid? Let's try with two different compilers: gcc 8.2: https://godbolt.org/z/ZcsChr https://godbolt.org/z/ZcsChr clang 3.8: https://godbolt.org/z/pVDCPi https://godbolt.org/z/pVDCPi It looks like at least gcc disagrees that reading uninitialized variables is a way to find out what's in memory.