rval-references.cpp
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// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -fsyntax-only -verify -std=c++11 %s
typedef int&& irr;
typedef irr& ilr_c1; // Collapses to int&
typedef int& ilr;
typedef ilr&& ilr_c2; // Collapses to int&
irr ret_irr() {
return 0; // expected-warning {{returning reference to local temporary}}
}
struct not_int {};
int over(int&);
not_int over(int&&);
int over2(const int&);
not_int over2(int&&);
struct conv_to_not_int_rvalue {
operator not_int &&();
};
typedef void (fun_type)();
void fun();
fun_type &&make_fun();
void f() {
int &&virr1; // expected-error {{declaration of reference variable 'virr1' requires an initializer}}
int &&virr2 = 0;
int &&virr3 = virr2; // expected-error {{rvalue reference to type 'int' cannot bind to lvalue of type 'int'}}
int i1 = 0;
const double d1 = 0;
const int ci1 = 1;
int &&virr4 = i1; // expected-error {{rvalue reference to type 'int' cannot bind to lvalue of type 'int'}}
int &&virr5 = ret_irr();
int &&virr6 = static_cast<int&&>(i1);
(void)static_cast<not_int &&>(i1); // expected-error {{reference to type 'not_int' could not bind to an lvalue of type 'int'}}
(void)static_cast<int &&>(static_cast<int const&&>(i1)); // expected-error {{cannot cast from rvalue of type 'const int' to rvalue reference type 'int &&'}}
(void)static_cast<int &&>(ci1); // expected-error {{types are not compatible}}
(void)static_cast<int &&>(d1);
int i2 = over(i1);
not_int ni1 = over(0);
int i3 = over(virr2);
not_int ni2 = over(ret_irr());
int i4 = over2(i1);
not_int ni3 = over2(0);
ilr_c1 vilr1 = i1;
ilr_c2 vilr2 = i1;
conv_to_not_int_rvalue cnir;
not_int &&ni4 = cnir;
not_int &ni5 = cnir; // expected-error{{non-const lvalue reference to type 'not_int' cannot bind to a value of unrelated type 'conv_to_not_int_rvalue'}}
not_int &&ni6 = conv_to_not_int_rvalue();
fun_type &&fun_ref = fun; // works because functions are special
fun_type &&fun_ref2 = make_fun(); // same
fun_type &fun_lref = make_fun(); // also special
try {
} catch(int&&) { // expected-error {{cannot catch exceptions by rvalue reference}}
}
}
int&& should_warn(int i) {
return static_cast<int&&>(i); // expected-warning {{reference to stack memory associated with parameter 'i' returned}}
}
int&& should_not_warn(int&& i) {
return static_cast<int&&>(i);
}
// Test the return dance. This also tests IsReturnCopyElidable.
struct MoveOnly {
MoveOnly();
MoveOnly(const MoveOnly&) = delete; // expected-note 3{{explicitly marked deleted here}}
};
MoveOnly gmo;
MoveOnly returningNonEligible() {
static MoveOnly mo;
MoveOnly &r = mo;
if (0) // Copy from global can't be elided
return gmo; // expected-error {{call to deleted constructor}}
else if (0) // Copy from local static can't be elided
return mo; // expected-error {{call to deleted constructor}}
else // Copy from reference can't be elided
return r; // expected-error {{call to deleted constructor}}
}