conversion-function.cpp 11.3 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474
// RUN: %clang_cc1 -triple %itanium_abi_triple -fsyntax-only -Wbind-to-temporary-copy -verify %s 
// RUN: %clang_cc1 -triple %itanium_abi_triple -fsyntax-only -Wbind-to-temporary-copy -verify -std=c++98 %s
// RUN: %clang_cc1 -triple %itanium_abi_triple -fsyntax-only -Wbind-to-temporary-copy -verify -std=c++11 %s

class X { 
public:
  operator bool();
  operator int() const;

  bool f() {
    return operator bool();
  }

  float g() {
    return operator float(); // expected-error{{use of undeclared 'operator float'}}
  }

  static operator short(); // expected-error{{conversion function must be a non-static member function}}
};

operator int(); // expected-error{{conversion function must be a non-static member function}}

operator int; // expected-error{{'operator int' cannot be the name of a variable or data member}}

typedef int func_type(int);
typedef int array_type[10];

class Y {
public:
  void operator bool(int, ...) const; // expected-error{{conversion function cannot have a return type}} \
  // expected-error{{conversion function cannot have any parameters}}

  operator bool(int a = 4, int b = 6) const; // expected-error{{conversion function cannot have any parameters}}
  
  
  operator float(...) const;  // expected-error{{conversion function cannot be variadic}}
  
  
  operator func_type(); // expected-error{{conversion function cannot convert to a function type}}
  operator array_type(); // expected-error{{conversion function cannot convert to an array type}}
};


typedef int INT;
typedef INT* INT_PTR;

class Z { 
  operator int(); // expected-note {{previous declaration is here}}
  operator int**(); // expected-note {{previous declaration is here}}
  
  operator INT();  // expected-error{{conversion function cannot be redeclared}}
  operator INT_PTR*(); // expected-error{{conversion function cannot be redeclared}}
};


class A { };

class B : public A {
public:
  operator A&() const; // expected-warning{{conversion function converting 'B' to its base class 'A' will never be used}}
  operator const void() const; // expected-warning{{conversion function converting 'B' to 'const void' will never be used}}
  operator const B(); // expected-warning{{conversion function converting 'B' to itself will never be used}}
};

class BaseA {};
class DerivedA;

class BaseB {
  virtual operator BaseA &() = 0;
  virtual operator DerivedA &() = 0;
};

class DerivedA : public BaseA, BaseB {
  virtual operator BaseA &();    // OK. Overrides BaseB::operatorBaseA&()
  virtual operator DerivedA &(); // OK. Overrides BaseB::operatorDerivedA&()
};

class DerivedB : public BaseA {
  virtual operator DerivedB &(); // expected-warning{{conversion function converting 'DerivedB' to itself will never be used}}
  virtual operator BaseA &();    // expected-warning{{conversion function converting 'DerivedB' to its base class 'BaseA' will never be used}}
};

// This used to crash Clang.
struct Flip;
struct Flop {
  Flop();
  Flop(const Flip&); // expected-note{{candidate constructor}}
};
struct Flip {
  operator Flop() const; // expected-note{{candidate function}}
};
Flop flop = Flip(); // expected-error {{conversion from 'Flip' to 'Flop' is ambiguous}}

// This tests that we don't add the second conversion declaration to the list of user conversions
struct C {
  operator const char *() const;
};

C::operator const char*() const { return 0; }

void f(const C& c) {
  const char* v = c;
}

// Test. Conversion in base class is visible in derived class.
class XB { 
public:
  operator int(); // expected-note {{candidate function}}
};

class Yb : public XB { 
public:
  operator char(); // expected-note {{candidate function}}
};

void f(Yb& a) {
  if (a) { } // expected-error {{conversion from 'Yb' to 'bool' is ambiguous}}
  int i = a; // OK. calls XB::operator int();
  char ch = a;  // OK. calls Yb::operator char();
}

// Test conversion + copy construction.
class AutoPtrRef { };

class AutoPtr {
  AutoPtr(AutoPtr &); // expected-note{{declared private here}}
  
public:
  AutoPtr();
  AutoPtr(AutoPtrRef);
  
  operator AutoPtrRef();
};

AutoPtr make_auto_ptr();

AutoPtr test_auto_ptr(bool Cond) {
  AutoPtr p1( make_auto_ptr() );
  
  AutoPtr p;
  if (Cond)
    return p; // expected-error{{calling a private constructor}}
  
  return AutoPtr();
}

struct A1 {
  A1(const char *);
  ~A1();

private:
  A1(const A1&); // expected-note 2 {{declared private here}}
};

A1 f() {
  // FIXME: redundant diagnostics!
  return "Hello"; // expected-error {{calling a private constructor}}
#if __cplusplus <= 199711L
  // expected-warning@-2 {{an accessible copy constructor}}
#else
  // expected-warning@-4 {{copying parameter of type 'A1' when binding a reference to a temporary would invoke an inaccessible constructor in C++98}}
#endif
}

namespace source_locations {
  template<typename T>
  struct sneaky_int {
    typedef int type;
  };

  template<typename T, typename U>
  struct A { };

  template<typename T>
  struct A<T, T> : A<T, int> { };

  struct E {
    template<typename T>
    operator A<T, typename sneaky_int<T>::type>&() const; // expected-note{{candidate function}}
  };

  void f() {
    A<float, float> &af = E(); // expected-error{{no viable conversion}}
    A<float, int> &af2 = E();
    const A<float, int> &caf2 = E();
  }

  // Check 
  template<typename T>
  struct E2 {
    operator T
    * // expected-error{{pointer to a reference}}
    () const;
  };

  E2<int&> e2i; // expected-note{{in instantiation}}
}

namespace crazy_declarators {
  struct A {
    (&operator bool())(); // expected-error {{use a typedef to declare a conversion to 'bool (&)()'}}
    *operator int();  // expected-error {{put the complete type after 'operator'}}
    // No suggestion of using a typedef here; that's not possible.
    template<typename T> (&operator T())();
#if __cplusplus <= 199711L
    // expected-error-re@-2 {{cannot specify any part of a return type in the declaration of a conversion function{{$}}}}
#else
    // expected-error-re@-4 {{cannot specify any part of a return type in the declaration of a conversion function; use an alias template to declare a conversion to 'T (&)()'{{$}}}}
#endif

  };
}

namespace smart_ptr {
  class Y { 
    class YRef { };

    Y(Y&);

  public:
    Y();
    Y(YRef);

    operator YRef(); // expected-note{{candidate function}}
  };

  struct X { // expected-note{{candidate constructor (the implicit copy constructor) not}}
#if __cplusplus >= 201103L
  // expected-note@-2 {{candidate constructor (the implicit move constructor) not}}
#endif

    explicit X(Y); // expected-note {{not a candidate}}
  };

  Y make_Y();

  X f() {
    X x = make_Y(); // expected-error{{no viable conversion from 'smart_ptr::Y' to 'smart_ptr::X'}}
    X x2(make_Y());
    return X(Y());
  }
}

struct Any {
  Any(...);
};

struct Other {
  Other(const Other &); 
  Other();
};

void test_any() {
  Any any = Other();
#if __cplusplus <= 199711L
  // expected-error@-2 {{cannot pass object of non-POD type 'Other' through variadic constructor; call will abort at runtime}}
#else
  // expected-error@-4 {{cannot pass object of non-trivial type 'Other' through variadic constructor; call will abort at runtime}}
#endif
}

namespace PR7055 {
  // Make sure that we don't allow too many conversions in an
  // auto_ptr-like template. In particular, we can't create multiple
  // temporary objects when binding to a reference.
  struct auto_ptr {
    struct auto_ptr_ref { };

    auto_ptr(auto_ptr&);
    auto_ptr(auto_ptr_ref);
    explicit auto_ptr(int *);

    operator auto_ptr_ref();
  };

  struct X {
    X(auto_ptr);
  };

  X f() {
    X x(auto_ptr(new int));
    return X(auto_ptr(new int));
  }

  auto_ptr foo();

  X e(foo());

  struct Y {
    Y(X);
  };
  
  Y f2(foo());
}

namespace PR7934 {
  typedef unsigned char uint8;

  struct MutablePtr {
    MutablePtr() : ptr(0) {}
    void *ptr;

    operator void*() { return ptr; }

  private:
    operator uint8*() { return reinterpret_cast<uint8*>(ptr); }
    operator const char*() const { return reinterpret_cast<const char*>(ptr); }
  };

  void fake_memcpy(const void *);

  void use() {
    MutablePtr ptr;
    fake_memcpy(ptr);
  }
}

namespace rdar8018274 {
  struct X { };
  struct Y {
    operator const struct X *() const;
  };

  struct Z : Y {
    operator struct X * ();
  };

  void test() {
    Z x;
    (void) (x != __null);
  }


  struct Base {
    operator int();
  };

  struct Derived1 : Base { };

  struct Derived2 : Base { };

  struct SuperDerived : Derived1, Derived2 { 
    using Derived1::operator int;
  };

  struct UeberDerived : SuperDerived {
    operator long();
  };

  void test2(UeberDerived ud) {
    int i = ud; // expected-error{{ambiguous conversion from derived class 'rdar8018274::SuperDerived' to base class 'rdar8018274::Base'}}
  }

  struct Base2 {
    operator int();
  };

  struct Base3 {
    operator int();
  };

  struct Derived23 : Base2, Base3 { 
    using Base2::operator int;
  };

  struct ExtraDerived23 : Derived23 { };

  void test3(ExtraDerived23 ed) {
    int i = ed;
  }
}

namespace PR8065 {
  template <typename T> struct Iterator;
  template <typename T> struct Container;

  template<>
  struct Iterator<int> {
    typedef Container<int> container_type;
  };

  template <typename T>
  struct Container {
    typedef typename Iterator<T>::container_type X;
    operator X(void) { return X(); }
  };

  Container<int> test;
}

namespace PR8034 {
  struct C {
    operator int();

  private:
    template <typename T> operator T();
  };
  int x = C().operator int();
}

namespace PR9336 {
  template<class T>
  struct generic_list
  {
    template<class Container>
    operator Container()
    { 
      Container ar;
      T* i;
      ar[0]=*i;
      return ar;
    }
  };

  template<class T>
  struct array
  {
    T& operator[](int);
    const T& operator[](int)const;
  };

  generic_list<generic_list<int> > l;
  array<array<int> > a = l;
}

namespace PR8800 {
  struct A;
  struct C {
    operator A&();
  };
  void f() {
    C c;
    A& a1(c);
    A& a2 = c;
    A& a3 = static_cast<A&>(c);
    A& a4 = (A&)c;
  }
}

namespace PR12712 {
  struct A {};
  struct B {
    operator A();
    operator A() const;
  };
  struct C : B {};

  A f(const C c) { return c; }
}

namespace PR18234 {
  struct A {
    operator enum E { e } (); // expected-error {{'PR18234::A::E' cannot be defined in a type specifier}}
    operator struct S { int n; } (); // expected-error {{'PR18234::A::S' cannot be defined in a type specifier}}
    // expected-note@-1 {{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'struct A' to 'const PR18234::A::S &' for 1st argument}}
#if __cplusplus >= 201103L
  // expected-note@-3 {{candidate constructor (the implicit move constructor) not viable: no known conversion from 'struct A' to 'PR18234::A::S &&' for 1st argument}}
#endif
  } a;
  A::S s = a; // expected-error {{no viable conversion from 'struct A' to 'A::S'}}
  A::E e = a;
  bool k1 = e == A::e; // expected-error {{no member named 'e'}}
  bool k2 = e.n == 0;
}

namespace PR30595 {
struct S {
  const operator int(); // expected-error {{cannot specify any part of a return type in the declaration of a conversion function; put the complete type after 'operator'}}
  const operator int() const; // expected-error {{cannot specify any part of a return type}}
  volatile const operator int(); // expected-error {{cannot specify any part of a return type}}

  operator const int() const;
};
}