llvm-project/clang/test/SemaTemplate/default-arguments.cpp

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// RUN: %clang_cc1 -fsyntax-only -verify %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++98 %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
template<typename T, int N = 2> struct X; // expected-note{{template is declared here}}
X<int, 1> *x1;
X<int> *x2;
X<> *x3; // expected-error{{too few template arguments for class template 'X'}}
template<typename U = float, int M> struct X;
X<> *x4;
template<typename T = int> struct Z { };
template struct Z<>;
// PR4362
template<class T> struct a { };
template<> struct a<int> { static const bool v = true; };
template<class T, bool = a<T>::v> struct p { }; // expected-error {{no member named 'v'}}
template struct p<bool>; // expected-note {{in instantiation of default argument for 'p<bool>' required here}}
template struct p<int>;
// PR5187
template<typename T, typename U>
struct A;
template<typename T, typename U = T>
struct A;
template<typename T, typename U>
struct A {
void f(A<T>);
};
template<typename T>
struct B { };
template<>
struct B<void> {
typedef B<void*> type;
};
// Nested default arguments for template parameters.
template<typename T> struct X1 { };
template<typename T>
struct X2 {
template<typename U = typename X1<T>::type> // expected-error{{no type named 'type' in 'X1<int>'}} \
// expected-error{{no type named 'type' in 'X1<char>'}}
struct Inner1 { }; // expected-note{{template is declared here}}
template<T Value = X1<T>::value> // expected-error{{no member named 'value' in 'X1<int>'}} \
// expected-error{{no member named 'value' in 'X1<char>'}}
struct NonType1 { }; // expected-note{{template is declared here}}
template<T Value>
struct Inner2 { };
template<typename U>
struct Inner3 {
template<typename X = T, typename V = U>
struct VeryInner { };
template<T Value1 = sizeof(T), T Value2 = sizeof(U),
T Value3 = Value1 + Value2>
struct NonType2 { };
};
};
X2<int> x2i; // expected-note{{in instantiation of template class 'X2<int>' requested here}}
X2<int>::Inner1<float> x2iif;
X2<int>::Inner1<> x2bad; // expected-error{{too few template arguments for class template 'Inner1'}}
X2<int>::NonType1<'a'> x2_nontype1;
X2<int>::NonType1<> x2_nontype1_bad; // expected-error{{too few template arguments for class template 'NonType1'}}
// Check multi-level substitution into template type arguments
X2<int>::Inner3<float>::VeryInner<> vi;
X2<char>::Inner3<int>::NonType2<> x2_deep_nontype; // expected-note{{in instantiation of template class 'X2<char>' requested here}}
template<typename T, typename U>
struct is_same { static const bool value = false; };
template<typename T>
struct is_same<T, T> { static const bool value = true; };
int array1[is_same<__typeof__(vi),
X2<int>::Inner3<float>::VeryInner<int, float> >::value? 1 : -1];
int array2[is_same<__typeof(x2_deep_nontype),
X2<char>::Inner3<int>::NonType2<sizeof(char), sizeof(int),
sizeof(char)+sizeof(int)> >::value? 1 : -1];
// Template template parameter defaults
template<template<typename T> class X = X2> struct X3 { };
int array3[is_same<X3<>, X3<X2> >::value? 1 : -1];
struct add_pointer {
template<typename T>
struct apply {
typedef T* type;
};
};
template<typename T, template<typename> class X = T::template apply>
struct X4;
int array4[is_same<X4<add_pointer>,
X4<add_pointer, add_pointer::apply> >::value? 1 : -1];
template<int> struct X5 {}; // expected-note{{has a different type 'int'}}
template<long> struct X5b {};
template<typename T,
template<T> class B = X5> // expected-error{{template template argument has different}} \
// expected-note{{previous non-type template parameter}}
struct X6 {};
X6<int> x6a;
X6<long> x6b; // expected-note{{while checking a default template argument}}
X6<long, X5b> x6c;
template<template<class> class X = B<int> > struct X7; // expected-error{{must be a class template}}
namespace PR9643 {
template<typename T> class allocator {};
template<typename T, typename U = allocator<T> > class vector {};
template<template<typename U, typename = allocator<U> > class container,
typename DT>
container<DT> initializer(const DT& d) {
return container<DT>();
}
void f() {
vector<int, allocator<int> > v = initializer<vector>(5);
}
}
namespace PR16288 {
template<typename X>
struct S {
template<typename T = int, typename U>
#if __cplusplus <= 199711L // C++03 or earlier modes
// expected-warning@-2 {{default template arguments for a function template are a C++11 extension}}
#endif
void f();
};
template<typename X>
template<typename T, typename U>
void S<X>::f() {}
}
namespace DR1635 {
template <class T> struct X {
template <class U = typename T::type> static void f(int) {} // expected-error {{type 'int' cannot be used prior to '::' because it has no members}}
#if __cplusplus <= 199711L // C++03 or earlier modes
// expected-warning@-2 {{default template arguments for a function template are a C++11 extension}}
#endif
static void f(...) {}
};
int g() { X<int>::f(0); } // expected-note {{in instantiation of template class 'DR1635::X<int>' requested here}}
}
namespace NondefDecls {
template<typename T> void f1() {
int g1(int defarg = T::error); // expected-error{{type 'int' cannot be used prior to '::' because it has no members}}
}
template void f1<int>(); // expected-note{{in instantiation of function template specialization 'NondefDecls::f1<int>' requested here}}
}
template <typename T>
struct C {
C(T t = ); // expected-error {{expected expression}}
};
C<int> obj;
namespace PR26134 {
// Make sure when substituting default template arguments we do it in the current context.
template<class T, bool Val = T::value>
struct X {};
template<bool B> struct Y {
void f() { X<Y> xy; }
static const bool value = B;
};
namespace ns1 {
template<class T0>
struct X {
template<bool B = T0::value> struct XInner { static const bool value = B; };
};
template<bool B> struct S { static const bool value = B; };
#if __cplusplus > 199711L
template<bool B> struct Y {
static constexpr bool f() { return typename X<S<B>>::template XInner<>{}.value; }
static_assert(f() == B, "");
};
Y<true> y;
Y<false> y2;
#endif
} // end ns1
} // end ns PR26134