Compiler error (C3431) using elaborated type specifiers for scoped enumerations by Nico Rieck

ISO/IEC 14882:2011 section 7.1.6.3 [dcl.type.elab]/3 states: "[...] the enum keyword shall be used to refer to an enumeration [...]".

When using an elaborated type specifier for a scoped enumeration, Visual C++ incorrectly requires "enum class":

enum class E { };
enum class E e1; // incorrect, but compiles
enum E e2; // correct, but yields: error C3431: 'E' : a scoped enumeration cannot be redeclared as an unscoped enumeration

Intellisense parses this correctly, and complains about the variant the compiler accepts.