diff options
Diffstat (limited to 'gcc/testsuite/g++.dg/template/sfinae11.C')
-rw-r--r-- | gcc/testsuite/g++.dg/template/sfinae11.C | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/gcc/testsuite/g++.dg/template/sfinae11.C b/gcc/testsuite/g++.dg/template/sfinae11.C new file mode 100644 index 000000000..a813055ea --- /dev/null +++ b/gcc/testsuite/g++.dg/template/sfinae11.C @@ -0,0 +1,53 @@ +// DR 339 +// +// Test of the use of the comma operator with SFINAE + +// Boilerplate helpers +typedef char yes_type; +struct no_type { char data[2]; }; + +template<typename T> T create_a(); +template<typename T> struct type { }; + +template<bool, typename T = void> struct enable_if { typedef T type; }; +template<typename T> struct enable_if<false, T> { }; + +#define JOIN( X, Y ) DO_JOIN( X, Y ) +#define DO_JOIN( X, Y ) DO_JOIN2(X,Y) +#define DO_JOIN2( X, Y ) X##Y + +template<typename T, typename U> + typename enable_if<(sizeof(create_a<T>(), create_a<U>()) > 0), + yes_type>::type + check_comma(int); + +template<typename T, typename U> no_type check_comma(...); + +template<typename T, typename U> +struct has_comma +{ + static const bool value = + (sizeof(check_comma<T, U>(0)) == sizeof(yes_type)); +}; + +#ifdef __GXX_EXPERIMENTAL_CXX0X__ +# define STATIC_ASSERT(Expr) static_assert(Expr, #Expr) +#else +# define STATIC_ASSERT(Expr) int JOIN(a,__LINE__)[Expr? 1 : -1] +#endif + +struct X { }; +struct Y { }; +struct Z { }; + +bool operator,(X&, Y); +bool operator,(X, Z); +void operator,(const Y&, const Z&); + +STATIC_ASSERT((has_comma<int, float>::value)); +STATIC_ASSERT((has_comma<int, X>::value)); +STATIC_ASSERT((has_comma<X, X>::value)); +STATIC_ASSERT((has_comma<X, Y>::value)); +STATIC_ASSERT((has_comma<X&, Y>::value)); +STATIC_ASSERT((has_comma<X, Z>::value)); +STATIC_ASSERT((!has_comma<Y, Z>::value)); |