Accessing inactive union members through char: the aliasing rule you didn't know about
Summary
The post explains that many would consider accessing an inactive union member UB, but a C++ aliasing exception allows reading through a char due to reinterpretation allowances. It uses an OptBool example and references the std::is_within_lifetime proposal to show when this is safe, emphasizing that char-types can alias any memory. The piece also discusses memory representation and practical implications for safe code in low-level C++.