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

147 lines
3.7 KiB
C++

// RUN: %clang_cc1 -fsyntax-only -verify %s
int g(int);
void f() {
int i;
int &r = i;
r = 1;
int *p = &r;
int &rr = r;
int (&rg)(int) = g;
rg(i);
int a[3];
int (&ra)[3] = a;
ra[1] = i;
int *Q;
int *& P = Q;
P[1] = 1;
}
typedef int t[1];
void test2() {
t a;
t& b = a;
int c[3];
int (&rc)[3] = c;
}
// C++ [dcl.init.ref]p5b1
struct A { };
struct B : A { } b;
void test3() {
double d = 2.0;
double& rd = d; // rd refers to d
const double& rcd = d; // rcd refers to d
A& ra = b; // ra refers to A subobject in b
const A& rca = b; // rca refers to A subobject in b
}
B fB();
// C++ [dcl.init.ref]p5b2
void test4() {
double& rd2 = 2.0; // expected-error{{non-const lvalue reference to type 'double' cannot bind to a temporary of type 'double'}}
int i = 2;
double& rd3 = i; // expected-error{{non-const lvalue reference to type 'double' cannot bind to a value of unrelated type 'int'}}
const A& rca = fB();
}
void test5() {
// const double& rcd2 = 2; // rcd2 refers to temporary with value 2.0
const volatile int cvi = 1;
const int& r = cvi; // expected-error{{binding of reference to type 'const int' to a value of type 'const volatile int' drops qualifiers}}
}
// C++ [dcl.init.ref]p3
int& test6(int& x) {
int& yo; // expected-error{{declaration of reference variable 'yo' requires an initializer}}
return x;
}
int& not_initialized_error; // expected-error{{declaration of reference variable 'not_initialized_error' requires an initializer}}
extern int& not_initialized_okay;
class Test6 { // expected-warning{{class 'Test6' does not declare any constructor to initialize its non-modifiable members}}
int& okay; // expected-note{{reference member 'okay' will never be initialized}}
};
struct C : B, A { };
void test7(C& c) {
A& a1 = c; // expected-error {{ambiguous conversion from derived class 'C' to base class 'A':}}
}
// C++ [dcl.ref]p1, C++ [dcl.ref]p4
void test8(int& const,// expected-error{{'const' qualifier may not be applied to a reference}}
void&, // expected-error{{cannot form a reference to 'void'}}
int& &) // expected-error{{type name declared as a reference to a reference}}
{
typedef int& intref;
typedef intref& intrefref; // C++ DR 106: reference collapsing
typedef intref const intref_c; // okay. FIXME: how do we verify that this is the same type as intref?
}
class string {
char *Data;
unsigned Length;
public:
string();
~string();
};
string getInput();
void test9() {
string &s = getInput(); // expected-error{{lvalue reference}}
}
void test10() {
__attribute((vector_size(16))) typedef int vec4;
typedef __attribute__(( ext_vector_type(4) )) int ext_vec4;
vec4 v;
int &a = v[0]; // expected-error{{non-const reference cannot bind to vector element}}
const int &b = v[0];
ext_vec4 ev;
int &c = ev.x; // expected-error{{non-const reference cannot bind to vector element}}
const int &d = ev.x;
}
namespace PR7149 {
template<typename T> struct X0
{
T& first;
X0(T& p1) : first(p1) { }
};
void f()
{
int p1[1];
X0< const int[1]> c(p1);
}
}
namespace PR8608 {
bool& f(unsigned char& c) { return (bool&)c; }
}
// The following crashed trying to recursively evaluate the LValue.
const int &do_not_crash = do_not_crash; // expected-warning{{reference 'do_not_crash' is not yet bound to a value when used within its own initialization}}
namespace ExplicitRefInit {
// This is invalid: we can't copy-initialize an 'A' temporary using an
// explicit constructor.
struct A { explicit A(int); };
const A &a(0); // expected-error {{reference to type 'const ExplicitRefInit::A' could not bind to an rvalue of type 'int'}}
}