78 lines · cpp
1// RUN: %clang_cc1 -fsyntax-only -std=c++03 -Wbind-to-temporary-copy -verify %s2 3// C++03 requires that we check for a copy constructor when binding a4// reference to a temporary, since we are allowed to make a copy, Even5// though we don't actually make that copy, make sure that we diagnose6// cases where that copy constructor is somehow unavailable. As an7// extension, this is only a warning.8 9struct X1 {10 X1();11 explicit X1(const X1&);12};13 14struct X2 {15 X2();16 17private:18 X2(const X2&); // expected-note{{declared private here}}19};20 21struct X3 {22 X3(); // expected-note{{requires 0 arguments, but 1 was provided}}23 24private:25 X3(X3&); // expected-note{{candidate constructor not viable: expects an lvalue for 1st argument}}26};27 28// Check for instantiation of default arguments29template<typename T>30T get_value_badly() {31 double *dp = 0;32 // The extension doesn't extend far enough to turn this error into a warning.33 T *tp = dp; // expected-error{{cannot initialize a variable of type 'int *' with an lvalue of type 'double *'}}34 return T();35}36 37template<typename T>38struct X4 {39 X4();40 X4(const X4&, T = get_value_badly<T>()); // expected-note{{in instantiation of}}41}; 42 43// Check for "dangerous" default arguments that could cause recursion.44struct X5 {45 X5();46 X5(const X5&, const X5& = X5()); // expected-error {{recursive evaluation of default argument}} expected-note {{used here}}47};48 49void g1(const X1&);50void g2(const X2&);51void g3(const X3&);52void g4(const X4<int>&);53void g5(const X5&);54 55void test() {56 g1(X1());57 g2(X2()); // expected-warning{{C++98 requires an accessible copy constructor for class 'X2' when binding a reference to a temporary; was private}}58 g3(X3()); // expected-warning{{no viable constructor copying parameter of type 'X3'}}59 g4(X4<int>());60 g5(X5());61}62 63// Check that unavailable copy constructors still cause SFINAE failures.64template<int> struct int_c { };65 66template<typename T> T f(const T&);67 68// Would be ambiguous with the next g(), except the instantiation failure in69// sizeof() prevents that.70template<typename T>71int &g(int_c<sizeof(f(T()))> * = 0);72 73template<typename T> float &g();74 75void h() {76 float &fp2 = g<X3>(); // Not ambiguous.77}78