llvm-project/clang/test/SemaCXX/rval-references.cpp

92 lines
2.5 KiB
C++

// RUN: clang-cc -fsyntax-only -verify -std=c++0x %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;
}
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 &&();
};
void f() {
int &&virr1; // expected-error {{declaration of reference variable 'virr1' requires an initializer}}
int &&virr2 = 0;
int &&virr3 = virr2; // expected-error {{rvalue reference cannot bind to lvalue}}
int i1 = 0;
int &&virr4 = i1; // expected-error {{rvalue reference cannot bind to lvalue}}
int &&virr5 = ret_irr();
int &&virr6 = static_cast<int&&>(i1);
(void)static_cast<not_int&&>(i1); // expected-error {{types are not compatible}}
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; // expected-error {{rvalue reference cannot bind to lvalue}}
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'}}
not_int &&ni6 = conv_to_not_int_rvalue();
try {
} catch(int&&) { // expected-error {{cannot catch exceptions by rvalue reference}}
}
}
int&& should_warn(int i) {
// FIXME: The stack address return test doesn't reason about casts.
return static_cast<int&&>(i); // xpected-warning {{returning reference to temporary}}
}
int&& should_not_warn(int&& i) { // But GCC 4.4 does
return static_cast<int&&>(i);
}
// Test the return dance. This also tests IsReturnCopyElidable.
struct MoveOnly {
MoveOnly();
MoveOnly(const MoveOnly&) = delete;
MoveOnly(MoveOnly&&);
MoveOnly(int&&);
};
MoveOnly returning() {
MoveOnly mo;
return mo;
}
MoveOnly gmo;
MoveOnly returningNonEligible() {
int i;
static MoveOnly mo;
MoveOnly &r = mo;
if (0) // Copy from global can't be elided
return gmo; // expected-error {{incompatible type returning}}
else if (0) // Copy from local static can't be elided
return mo; // expected-error {{incompatible type returning}}
else if (0) // Copy from reference can't be elided
return r; // expected-error {{incompatible type returning}}
else // Construction from different type can't be elided
return i; // expected-error {{incompatible type returning}}
}