nonstandard extension used : class rvalue used as lvalue
For compatibility with previous versions of Visual C++, Microsoft extensions (/Ze) allow you to use a class type as an rvalue in a context that implicitly or explicitly takes its address. In some cases, such as the example below, this can be dangerous.
Example
struct C { C(); }; C * pC = &C(); // yields C4238
This usage causes an error under ANSI compatibility (/Za).