rval-references.cpp revision cc5306ac8a39cdd5e7f83e597cba911e97c4a595
1// RUN: clang-cc -fsyntax-only -verify -std=c++0x %s 2 3typedef int&& irr; 4typedef irr& ilr_c1; // Collapses to int& 5typedef int& ilr; 6typedef ilr&& ilr_c2; // Collapses to int& 7 8irr ret_irr() { 9 return 0; 10} 11 12struct not_int {}; 13 14int over(int&); 15not_int over(int&&); 16 17int over2(const int&); 18not_int over2(int&&); 19 20struct conv_to_not_int_rvalue { 21 operator not_int &&(); 22}; 23 24void f() { 25 int &&virr1; // expected-error {{declaration of reference variable 'virr1' requires an initializer}} 26 int &&virr2 = 0; 27 int &&virr3 = virr2; // expected-error {{rvalue reference cannot bind to lvalue}} 28 int i1 = 0; 29 int &&virr4 = i1; // expected-error {{rvalue reference cannot bind to lvalue}} 30 int &&virr5 = ret_irr(); 31 int &&virr6 = static_cast<int&&>(i1); 32 (void)static_cast<not_int&&>(i1); // expected-error {{types are not compatible}} 33 34 int i2 = over(i1); 35 not_int ni1 = over(0); 36 int i3 = over(virr2); 37 not_int ni2 = over(ret_irr()); 38 39 int i4 = over2(i1); 40 not_int ni3 = over2(0); 41 42 ilr_c1 vilr1 = i1; 43 ilr_c2 vilr2 = i1; 44 45 conv_to_not_int_rvalue cnir; 46 not_int &&ni4 = cnir; // expected-error {{rvalue reference cannot bind to lvalue}} 47 not_int &ni5 = cnir; // expected-error{{non-const lvalue reference to type 'struct not_int' cannot be initialized with a value of type 'struct conv_to_not_int_rvalue'}} 48 not_int &&ni6 = conv_to_not_int_rvalue(); 49 50 51 try { 52 } catch(int&&) { // expected-error {{cannot catch exceptions by rvalue reference}} 53 } 54} 55 56int&& should_warn(int i) { 57 // FIXME: The stack address return test doesn't reason about casts. 58 return static_cast<int&&>(i); // xpected-warning {{returning reference to temporary}} 59} 60int&& should_not_warn(int&& i) { // But GCC 4.4 does 61 return static_cast<int&&>(i); 62} 63 64 65// Test the return dance. This also tests IsReturnCopyElidable. 66struct MoveOnly { 67 MoveOnly(); 68 MoveOnly(const MoveOnly&) = delete; // expected-note {{candidate function}} 69 MoveOnly(MoveOnly&&); // expected-note {{candidate function}} 70 MoveOnly(int&&); // expected-note {{candidate function}} 71}; 72 73MoveOnly returning() { 74 MoveOnly mo; 75 return mo; 76} 77 78MoveOnly gmo; 79MoveOnly returningNonEligible() { 80 int i; 81 static MoveOnly mo; 82 MoveOnly &r = mo; 83 if (0) // Copy from global can't be elided 84 return gmo; // expected-error {{incompatible type returning}} 85 else if (0) // Copy from local static can't be elided 86 return mo; // expected-error {{incompatible type returning}} 87 else if (0) // Copy from reference can't be elided 88 return r; // expected-error {{incompatible type returning}} 89 else // Construction from different type can't be elided 90 return i; // expected-error {{no viable conversion from 'int' to 'struct MoveOnly'}} 91} 92