diff options
Diffstat (limited to 'gcc/testsuite/g++.dg/template/sfinae12.C')
-rw-r--r-- | gcc/testsuite/g++.dg/template/sfinae12.C | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/gcc/testsuite/g++.dg/template/sfinae12.C b/gcc/testsuite/g++.dg/template/sfinae12.C new file mode 100644 index 000000000..c51211be2 --- /dev/null +++ b/gcc/testsuite/g++.dg/template/sfinae12.C @@ -0,0 +1,47 @@ +// DR 339 +// +// Test of the use of the ternary 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 V> +typename enable_if< + (sizeof((create_a<T>()? create_a<U>() : create_a<V>()), 0) > 0), + yes_type>::type + check_ternary(int); + +template<typename T, typename U, typename V> no_type check_ternary(...); + +template<typename T, typename U, typename V> +struct has_ternary +{ + static const bool value = + (sizeof(check_ternary<T, U, V>(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 { operator bool(); }; + +STATIC_ASSERT((has_ternary<int, float, double>::value)); +STATIC_ASSERT((has_ternary<bool, double, double>::value)); +STATIC_ASSERT((!has_ternary<int, float*, double>::value)); +STATIC_ASSERT((!has_ternary<X, double, double>::value)); +STATIC_ASSERT((has_ternary<Y, double, double>::value)); |