id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
1828	is_class maybe triggering a VC8 compiler bug	Stefan	John Maddock	"The following code compiles with an error. However there shouldn't be an error. Basically, the line in main() fails to compile because the compiler thinks sizeof(&Der::foo) is 16, which just can't be so. This case is very intricate, and any modifications to the code compile cleanly. For example, if instead of is_class, we use is_void, the code compiles; if hasher is not partially specialized for pointers, it compiles; if 'base' doesn't use CRTP, it compiles; if hasher<T> isn't a member variable, it compiles; if hasher is parametrized by T* or something else, it compiles.

 #include <boost/type_traits/is_class.hpp>
 template <class T> struct hasher {};
 template <class T> struct hasher<T*>
 	: boost::is_class<T>
 {};
 template <class T>
 struct hash_set
 {
 	hasher<T> hash;
 };
 template <class D>
 struct base
 {
 	hash_set<D*> set;
 };
 struct Der
 	: public base<Der>
 {
 	void foo();
 };
 int main()
 {
 	char x[sizeof(&Der::foo) == 16 ? -1 : 1];
 }

I don't think this is a boost bug - the failing conditions look too much like a compiler-specific bug. Also, this code compiles cleanly on gcc 3.4.2

I'd like to hear your opinion, and forward the bug to Microsoft if it's really their bug."	Bugs	closed	Boost 1.36.0	type_traits	Boost 1.34.1	Problem	fixed