constant-expression-cxx11.cpp revision c216a01c96d83bd9a90e214af64913e93d39aacc 
1// RUN: %clang_cc1 -triple i686-linux -fsyntax-only -verify -std=c++11 -pedantic %s -Wno-comment
2
3namespace StaticAssertFoldTest {
4
5int x;
6static_assert(++x, "test"); // expected-error {{not an integral constant expression}}
7static_assert(false, "test"); // expected-error {{test}}
8
9}
10
11// FIXME: support const T& parameters here.
12//template<typename T> constexpr T id(const T &t) { return t; }
13template<typename T> constexpr T id(T t) { return t; }
14// FIXME: support templates here.
15//template<typename T> constexpr T min(const T &a, const T &b) {
16//  return a < b ? a : b;
17//}
18//template<typename T> constexpr T max(const T &a, const T &b) {
19//  return a < b ? b : a;
20//}
21constexpr int min(const int &a, const int &b) { return a < b ? a : b; }
22constexpr int max(const int &a, const int &b) { return a < b ? b : a; }
23
24struct MemberZero {
25  constexpr int zero() { return 0; }
26};
27
28namespace DerivedToVBaseCast {
29
30  struct U { int n; };
31  struct V : U { int n; };
32  struct A : virtual V { int n; };
33  struct Aa { int n; };
34  struct B : virtual A, Aa {};
35  struct C : virtual A, Aa {};
36  struct D : B, C {};
37
38  D d;
39  constexpr B *p = &d;
40  constexpr C *q = &d;
41  static_assert((void*)p != (void*)q, "");
42  static_assert((A*)p == (A*)q, "");
43  static_assert((Aa*)p != (Aa*)q, "");
44
45  constexpr B &pp = d;
46  constexpr C &qq = d;
47  static_assert((void*)&pp != (void*)&qq, "");
48  static_assert(&(A&)pp == &(A&)qq, "");
49  static_assert(&(Aa&)pp != &(Aa&)qq, "");
50
51  constexpr V *v = p;
52  constexpr V *w = q;
53  constexpr V *x = (A*)p;
54  static_assert(v == w, "");
55  static_assert(v == x, "");
56
57  static_assert((U*)&d == p, "");
58  static_assert((U*)&d == q, "");
59  static_assert((U*)&d == v, "");
60  static_assert((U*)&d == w, "");
61  static_assert((U*)&d == x, "");
62
63  struct X {};
64  struct Y1 : virtual X {};
65  struct Y2 : X {};
66  struct Z : Y1, Y2 {};
67  Z z;
68  static_assert((X*)(Y1*)&z != (X*)(Y2*)&z, "");
69
70}
71
72namespace ConstCast {
73
74constexpr int n1 = 0;
75constexpr int n2 = const_cast<int&>(n1);
76constexpr int *n3 = const_cast<int*>(&n1);
77constexpr int n4 = *const_cast<int*>(&n1);
78constexpr const int * const *n5 = const_cast<const int* const*>(&n3);
79constexpr int **n6 = const_cast<int**>(&n3);
80constexpr int n7 = **n5;
81constexpr int n8 = **n6;
82
83}
84
85namespace TemplateArgumentConversion {
86  template<int n> struct IntParam {};
87
88  using IntParam0 = IntParam<0>;
89  // FIXME: This should be accepted once we implement the new ICE rules.
90  using IntParam0 = IntParam<id(0)>; // expected-error {{not an integral constant expression}}
91  using IntParam0 = IntParam<MemberZero().zero>; // expected-error {{did you mean to call it with no arguments?}} expected-error {{not an integral constant expression}}
92}
93
94namespace CaseStatements {
95  void f(int n) {
96    switch (n) {
97    // FIXME: Produce the 'add ()' fixit for this.
98    case MemberZero().zero: // desired-error {{did you mean to call it with no arguments?}} expected-error {{not an integer constant expression}}
99    // FIXME: This should be accepted once we implement the new ICE rules.
100    case id(1): // expected-error {{not an integer constant expression}}
101      return;
102    }
103  }
104}
105
106extern int &Recurse1;
107int &Recurse2 = Recurse1, &Recurse1 = Recurse2;
108constexpr int &Recurse3 = Recurse2; // expected-error {{must be initialized by a constant expression}}
109
110namespace MemberEnum {
111  struct WithMemberEnum {
112    enum E { A = 42 };
113  } wme;
114
115  static_assert(wme.A == 42, "");
116}
117
118namespace DefaultArguments {
119
120const int z = int();
121constexpr int Sum(int a = 0, const int &b = 0, const int *c = &z, char d = 0) {
122  return a + b + *c + d;
123}
124const int four = 4;
125constexpr int eight = 8;
126constexpr const int twentyseven = 27;
127static_assert(Sum() == 0, "");
128static_assert(Sum(1) == 1, "");
129static_assert(Sum(1, four) == 5, "");
130static_assert(Sum(1, eight, &twentyseven) == 36, "");
131static_assert(Sum(1, 2, &four, eight) == 15, "");
132
133}
134
135namespace Ellipsis {
136
137// Note, values passed through an ellipsis can't actually be used.
138constexpr int F(int a, ...) { return a; }
139static_assert(F(0) == 0, "");
140static_assert(F(1, 0) == 1, "");
141static_assert(F(2, "test") == 2, "");
142static_assert(F(3, &F) == 3, "");
143int k = 0;
144static_assert(F(4, k) == 3, ""); // expected-error {{constant expression}}
145
146}
147
148namespace Recursion {
149  constexpr int fib(int n) { return n > 1 ? fib(n-1) + fib(n-2) : n; }
150  static_assert(fib(11) == 89, "");
151
152  constexpr int gcd_inner(int a, int b) {
153    return b == 0 ? a : gcd_inner(b, a % b);
154  }
155  constexpr int gcd(int a, int b) {
156    return gcd_inner(max(a, b), min(a, b));
157  }
158
159  static_assert(gcd(1749237, 5628959) == 7, "");
160}
161
162namespace FunctionCast {
163  // When folding, we allow functions to be cast to different types. Such
164  // cast functions cannot be called, even if they're constexpr.
165  constexpr int f() { return 1; }
166  typedef double (*DoubleFn)();
167  typedef int (*IntFn)();
168  int a[(int)DoubleFn(f)()]; // expected-error {{variable length array}} expected-warning{{extension}}
169  int b[(int)IntFn(f)()];    // ok
170}
171
172namespace StaticMemberFunction {
173  struct S {
174    static constexpr int k = 42;
175    static constexpr int f(int n) { return n * k + 2; }
176  } s;
177
178  constexpr int n = s.f(19);
179  static_assert(S::f(19) == 800, "");
180  static_assert(s.f(19) == 800, "");
181  static_assert(n == 800, "");
182
183  constexpr int (*sf1)(int) = &S::f;
184  constexpr int (*sf2)(int) = &s.f;
185  constexpr const int *sk = &s.k;
186}
187
188namespace ParameterScopes {
189
190  const int k = 42;
191  constexpr const int &ObscureTheTruth(const int &a) { return a; }
192  constexpr const int &MaybeReturnJunk(bool b, const int a) {
193    return ObscureTheTruth(b ? a : k);
194  }
195  static_assert(MaybeReturnJunk(false, 0) == 42, ""); // ok
196  constexpr int a = MaybeReturnJunk(true, 0); // expected-error {{constant expression}}
197
198  constexpr const int MaybeReturnNonstaticRef(bool b, const int a) {
199    // If ObscureTheTruth returns a reference to 'a', the result is not a
200    // constant expression even though 'a' is still in scope.
201    return ObscureTheTruth(b ? a : k);
202  }
203  static_assert(MaybeReturnNonstaticRef(false, 0) == 42, ""); // ok
204  constexpr int b = MaybeReturnNonstaticRef(true, 0); // expected-error {{constant expression}}
205
206  constexpr int InternalReturnJunk(int n) {
207    // FIXME: We should reject this: it never produces a constant expression.
208    return MaybeReturnJunk(true, n);
209  }
210  constexpr int n3 = InternalReturnJunk(0); // expected-error {{must be initialized by a constant expression}}
211
212  constexpr int LToR(int &n) { return n; }
213  constexpr int GrabCallersArgument(bool which, int a, int b) {
214    return LToR(which ? b : a);
215  }
216  static_assert(GrabCallersArgument(false, 1, 2) == 1, "");
217  static_assert(GrabCallersArgument(true, 4, 8) == 8, "");
218
219}
220
221namespace Pointers {
222
223  constexpr int f(int n, const int *a, const int *b, const int *c) {
224    return n == 0 ? 0 : *a + f(n-1, b, c, a);
225  }
226
227  const int x = 1, y = 10, z = 100;
228  static_assert(f(23, &x, &y, &z) == 788, "");
229
230  constexpr int g(int n, int a, int b, int c) {
231    return f(n, &a, &b, &c);
232  }
233  static_assert(g(23, x, y, z) == 788, "");
234
235}
236
237namespace FunctionPointers {
238
239  constexpr int Double(int n) { return 2 * n; }
240  constexpr int Triple(int n) { return 3 * n; }
241  constexpr int Twice(int (*F)(int), int n) { return F(F(n)); }
242  constexpr int Quadruple(int n) { return Twice(Double, n); }
243  constexpr auto Select(int n) -> int (*)(int) {
244    return n == 2 ? &Double : n == 3 ? &Triple : n == 4 ? &Quadruple : 0;
245  }
246  constexpr int Apply(int (*F)(int), int n) { return F(n); }
247
248  static_assert(1 + Apply(Select(4), 5) + Apply(Select(3), 7) == 42, "");
249
250  constexpr int Invalid = Apply(Select(0), 0); // expected-error {{must be initialized by a constant expression}}
251
252}
253
254namespace PointerComparison {
255
256int x, y;
257static_assert(&x == &y, "false"); // expected-error {{false}}
258static_assert(&x != &y, "");
259constexpr bool g1 = &x == &y;
260constexpr bool g2 = &x != &y;
261constexpr bool g3 = &x <= &y; // expected-error {{must be initialized by a constant expression}}
262constexpr bool g4 = &x >= &y; // expected-error {{must be initialized by a constant expression}}
263constexpr bool g5 = &x < &y; // expected-error {{must be initialized by a constant expression}}
264constexpr bool g6 = &x > &y; // expected-error {{must be initialized by a constant expression}}
265
266struct S { int x, y; } s;
267static_assert(&s.x == &s.y, "false"); // expected-error {{false}}
268static_assert(&s.x != &s.y, "");
269static_assert(&s.x <= &s.y, "");
270static_assert(&s.x >= &s.y, "false"); // expected-error {{false}}
271static_assert(&s.x < &s.y, "");
272static_assert(&s.x > &s.y, "false"); // expected-error {{false}}
273
274static_assert(0 == &y, "false"); // expected-error {{false}}
275static_assert(0 != &y, "");
276constexpr bool n3 = 0 <= &y; // expected-error {{must be initialized by a constant expression}}
277constexpr bool n4 = 0 >= &y; // expected-error {{must be initialized by a constant expression}}
278constexpr bool n5 = 0 < &y; // expected-error {{must be initialized by a constant expression}}
279constexpr bool n6 = 0 > &y; // expected-error {{must be initialized by a constant expression}}
280
281static_assert(&x == 0, "false"); // expected-error {{false}}
282static_assert(&x != 0, "");
283constexpr bool n9 = &x <= 0; // expected-error {{must be initialized by a constant expression}}
284constexpr bool n10 = &x >= 0; // expected-error {{must be initialized by a constant expression}}
285constexpr bool n11 = &x < 0; // expected-error {{must be initialized by a constant expression}}
286constexpr bool n12 = &x > 0; // expected-error {{must be initialized by a constant expression}}
287
288static_assert(&x == &x, "");
289static_assert(&x != &x, "false"); // expected-error {{false}}
290static_assert(&x <= &x, "");
291static_assert(&x >= &x, "");
292static_assert(&x < &x, "false"); // expected-error {{false}}
293static_assert(&x > &x, "false"); // expected-error {{false}}
294
295constexpr S* sptr = &s;
296// FIXME: This is not a constant expression; check we reject this and move this
297// test elsewhere.
298constexpr bool dyncast = sptr == dynamic_cast<S*>(sptr);
299
300struct Str {
301  // FIXME: In C++ mode, we should say 'integral' not 'integer'
302  int a : dynamic_cast<S*>(sptr) == dynamic_cast<S*>(sptr); // \
303    expected-warning {{not integer constant expression}} \
304    expected-note {{dynamic_cast not allowed in a constant expression}}
305  int b : reinterpret_cast<S*>(sptr) == reinterpret_cast<S*>(sptr); // \
306    expected-warning {{not integer constant expression}} \
307    expected-note {{reinterpret_cast not allowed in a constant expression}}
308  int c : (S*)(long)(sptr) == (S*)(long)(sptr); // \
309    expected-warning {{not integer constant expression}} \
310    expected-note {{reinterpreting cast not allowed in a constant expression}}
311  int d : (S*)(42) == (S*)(42); // \
312    expected-warning {{not integer constant expression}} \
313    expected-note {{reinterpreting cast not allowed in a constant expression}}
314  int e : (Str*)(sptr) == (Str*)(sptr); // \
315    expected-warning {{not integer constant expression}} \
316    expected-note {{reinterpreting cast not allowed in a constant expression}}
317  int f : &(Str&)(*sptr) == &(Str&)(*sptr); // \
318    expected-warning {{not integer constant expression}} \
319    expected-note {{reinterpreting cast not allowed in a constant expression}}
320  int g : (S*)(void*)(sptr) == sptr; // \
321    expected-warning {{not integer constant expression}} \
322    expected-note {{reinterpreting cast not allowed in a constant expression}}
323};
324
325extern char externalvar[];
326// FIXME: This is not a constant expression; check we reject this and move this
327// test elsewhere.
328constexpr bool constaddress = (void *)externalvar == (void *)0x4000UL; // expected-error {{must be initialized by a constant expression}}
329constexpr bool litaddress = "foo" == "foo"; // expected-error {{must be initialized by a constant expression}} expected-warning {{unspecified}}
330static_assert(0 != "foo", "");
331
332}
333
334namespace MaterializeTemporary {
335
336constexpr int f(const int &r) { return r; }
337constexpr int n = f(1);
338
339constexpr bool same(const int &a, const int &b) { return &a == &b; }
340constexpr bool sameTemporary(const int &n) { return same(n, n); }
341
342static_assert(n, "");
343static_assert(!same(4, 4), "");
344static_assert(same(n, n), "");
345static_assert(sameTemporary(9), "");
346
347}
348
349constexpr int strcmp_ce(const char *p, const char *q) {
350  return (!*p || *p != *q) ? *p - *q : strcmp_ce(p+1, q+1);
351}
352
353namespace StringLiteral {
354
355// FIXME: Refactor this once we support constexpr templates.
356constexpr int MangleChars(const char *p) {
357  return *p + 3 * (*p ? MangleChars(p+1) : 0);
358}
359constexpr int MangleChars(const char16_t *p) {
360  return *p + 3 * (*p ? MangleChars(p+1) : 0);
361}
362constexpr int MangleChars(const char32_t *p) {
363  return *p + 3 * (*p ? MangleChars(p+1) : 0);
364}
365
366static_assert(MangleChars("constexpr!") == 1768383, "");
367static_assert(MangleChars(u"constexpr!") == 1768383, "");
368static_assert(MangleChars(U"constexpr!") == 1768383, "");
369
370constexpr char c0 = "nought index"[0];
371constexpr char c1 = "nice index"[10];
372constexpr char c2 = "nasty index"[12]; // expected-error {{must be initialized by a constant expression}} expected-warning {{is past the end}}
373constexpr char c3 = "negative index"[-1]; // expected-error {{must be initialized by a constant expression}} expected-warning {{is before the beginning}}
374constexpr char c4 = ((char*)(int*)"no reinterpret_casts allowed")[14]; // expected-error {{must be initialized by a constant expression}}
375
376constexpr const char *p = "test" + 2;
377static_assert(*p == 's', "");
378
379constexpr const char *max_iter(const char *a, const char *b) {
380  return *a < *b ? b : a;
381}
382constexpr const char *max_element(const char *a, const char *b) {
383  return (a+1 >= b) ? a : max_iter(a, max_element(a+1, b));
384}
385
386constexpr const char *begin(const char (&arr)[45]) { return arr; }
387constexpr const char *end(const char (&arr)[45]) { return arr + 45; }
388
389constexpr char str[] = "the quick brown fox jumped over the lazy dog";
390constexpr const char *max = max_element(begin(str), end(str));
391static_assert(*max == 'z', "");
392static_assert(max == str + 38, "");
393
394static_assert(strcmp_ce("hello world", "hello world") == 0, "");
395static_assert(strcmp_ce("hello world", "hello clang") > 0, "");
396static_assert(strcmp_ce("constexpr", "test") < 0, "");
397static_assert(strcmp_ce("", " ") < 0, "");
398
399}
400
401namespace Array {
402
403// FIXME: Use templates for these once we support constexpr templates.
404constexpr int Sum(const int *begin, const int *end) {
405  return begin == end ? 0 : *begin + Sum(begin+1, end);
406}
407constexpr const int *begin(const int (&xs)[5]) { return xs; }
408constexpr const int *end(const int (&xs)[5]) { return xs + 5; }
409
410constexpr int xs[] = { 1, 2, 3, 4, 5 };
411constexpr int ys[] = { 5, 4, 3, 2, 1 };
412constexpr int sum_xs = Sum(begin(xs), end(xs));
413static_assert(sum_xs == 15, "");
414
415constexpr int ZipFoldR(int (*F)(int x, int y, int c), int n,
416                       const int *xs, const int *ys, int c) {
417  return n ? F(*xs, *ys, ZipFoldR(F, n-1, xs+1, ys+1, c)) : c;
418}
419constexpr int MulAdd(int x, int y, int c) { return x * y + c; }
420constexpr int InnerProduct = ZipFoldR(MulAdd, 5, xs, ys, 0);
421static_assert(InnerProduct == 35, "");
422
423constexpr int SubMul(int x, int y, int c) { return (x - y) * c; }
424constexpr int DiffProd = ZipFoldR(SubMul, 2, xs+3, ys+3, 1);
425static_assert(DiffProd == 8, "");
426static_assert(ZipFoldR(SubMul, 3, xs+3, ys+3, 1), ""); // expected-error {{constant expression}}
427
428constexpr const int *p = xs + 3;
429constexpr int xs4 = p[1]; // ok
430constexpr int xs5 = p[2]; // expected-error {{constant expression}}
431constexpr int xs0 = p[-3]; // ok
432constexpr int xs_1 = p[-4]; // expected-error {{constant expression}}
433
434constexpr int zs[2][2][2][2] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
435static_assert(zs[0][0][0][0] == 1, "");
436static_assert(zs[1][1][1][1] == 16, "");
437static_assert(zs[0][0][0][2] == 3, ""); // expected-error {{constant expression}}
438static_assert((&zs[0][0][0][2])[-1] == 2, "");
439static_assert(**(**(zs + 1) + 1) == 11, "");
440static_assert(*(&(&(*(*&(&zs[2] - 1)[0] + 2 - 2))[2])[-1][-1] + 1) == 11, "");
441
442constexpr int arr[40] = { 1, 2, 3, [8] = 4 }; // expected-warning {{extension}}
443constexpr int SumNonzero(const int *p) {
444  return *p + (*p ? SumNonzero(p+1) : 0);
445}
446constexpr int CountZero(const int *p, const int *q) {
447  return p == q ? 0 : (*p == 0) + CountZero(p+1, q);
448}
449static_assert(SumNonzero(arr) == 6, "");
450static_assert(CountZero(arr, arr + 40) == 36, "");
451
452struct ArrayElem {
453  constexpr ArrayElem() : n(0) {}
454  int n;
455  constexpr int f() { return n; }
456};
457struct ArrayRVal {
458  constexpr ArrayRVal() {}
459  ArrayElem elems[10];
460};
461static_assert(ArrayRVal().elems[3].f() == 0, "");
462
463}
464
465namespace DependentValues {
466
467struct I { int n; typedef I V[10]; };
468I::V x, y;
469template<bool B> struct S {
470  int k;
471  void f() {
472    I::V &cells = B ? x : y;
473    I &i = cells[k];
474    switch (i.n) {}
475  }
476};
477
478}
479
480namespace Class {
481
482struct A { constexpr A(int a, int b) : k(a + b) {} int k; };
483constexpr int fn(const A &a) { return a.k; }
484static_assert(fn(A(4,5)) == 9, "");
485
486struct B { int n; int m; } constexpr b = { 0, b.n }; // expected-warning {{uninitialized}}
487struct C {
488  constexpr C(C *this_) : m(42), n(this_->m) {} // ok
489  int m, n;
490};
491struct D {
492  C c;
493  constexpr D() : c(&c) {}
494};
495static_assert(D().c.n == 42, "");
496
497struct E {
498  constexpr E() : p(&p) {}
499  void *p;
500};
501constexpr const E &e1 = E(); // expected-error {{constant expression}}
502// This is a constant expression if we elide the copy constructor call, and
503// is not a constant expression if we don't! But we do, so it is.
504// FIXME: The move constructor is not currently implicitly defined as constexpr.
505// We notice this when evaluating an expression which uses it, but not when
506// checking its initializer.
507constexpr E e2 = E(); // unexpected-error {{constant expression}}
508static_assert(e2.p == &e2.p, ""); // unexpected-error {{constant expression}}
509// FIXME: We don't pass through the fact that 'this' is ::e3 when checking the
510// initializer of this declaration.
511constexpr E e3; // unexpected-error {{constant expression}}
512static_assert(e3.p == &e3.p, "");
513
514extern const class F f;
515struct F {
516  constexpr F() : p(&f.p) {}
517  const void *p;
518};
519constexpr F f = F();
520
521struct G {
522  struct T {
523    constexpr T(T *p) : u1(), u2(p) {}
524    union U1 {
525      constexpr U1() {}
526      int a, b = 42;
527    } u1;
528    union U2 {
529      constexpr U2(T *p) : c(p->u1.b) {}
530      int c, d;
531    } u2;
532  } t;
533  constexpr G() : t(&t) {}
534} constexpr g;
535
536static_assert(g.t.u1.a == 42, ""); // expected-error {{constant expression}}
537static_assert(g.t.u1.b == 42, "");
538static_assert(g.t.u2.c == 42, "");
539static_assert(g.t.u2.d == 42, ""); // expected-error {{constant expression}}
540
541struct S {
542  int a, b;
543  const S *p;
544  double d;
545  const char *q;
546
547  constexpr S(int n, const S *p) : a(5), b(n), p(p), d(n), q("hello") {}
548};
549
550S global(43, &global);
551
552static_assert(S(15, &global).b == 15, "");
553
554constexpr bool CheckS(const S &s) {
555  return s.a == 5 && s.b == 27 && s.p == &global && s.d == 27. && s.q[3] == 'l';
556}
557static_assert(CheckS(S(27, &global)), "");
558
559struct Arr {
560  char arr[3];
561  constexpr Arr() : arr{'x', 'y', 'z'} {}
562};
563constexpr int hash(Arr &&a) {
564  return a.arr[0] + a.arr[1] * 0x100 + a.arr[2] * 0x10000;
565}
566constexpr int k = hash(Arr());
567static_assert(k == 0x007a7978, "");
568
569
570struct AggregateInit {
571  const char &c;
572  int n;
573  double d;
574  int arr[5];
575  void *p;
576};
577
578constexpr AggregateInit agg1 = { "hello"[0] };
579
580static_assert(strcmp_ce(&agg1.c, "hello") == 0, "");
581static_assert(agg1.n == 0, "");
582static_assert(agg1.d == 0.0, "");
583static_assert(agg1.arr[-1] == 0, ""); // expected-error {{constant expression}}
584static_assert(agg1.arr[0] == 0, "");
585static_assert(agg1.arr[4] == 0, "");
586static_assert(agg1.arr[5] == 0, ""); // expected-error {{constant expression}}
587static_assert(agg1.p == nullptr, "");
588
589namespace SimpleDerivedClass {
590
591struct B {
592  constexpr B(int n) : a(n) {}
593  int a;
594};
595struct D : B {
596  constexpr D(int n) : B(n) {}
597};
598constexpr D d(3);
599static_assert(d.a == 3, "");
600
601}
602
603struct Bottom { constexpr Bottom() {} };
604struct Base : Bottom {
605  constexpr Base(int a = 42, const char *b = "test") : a(a), b(b) {}
606  int a;
607  const char *b;
608};
609struct Base2 : Bottom {
610  constexpr Base2(const int &r) : r(r) {}
611  int q = 123;
612  // FIXME: When we track the global for which we are computing the initializer,
613  // use a reference here.
614  //const int &r;
615  int r;
616};
617struct Derived : Base, Base2 {
618  constexpr Derived() : Base(76), Base2(a) {}
619  int c = r + b[1];
620};
621
622constexpr bool operator==(const Base &a, const Base &b) {
623  return a.a == b.a && strcmp_ce(a.b, b.b) == 0;
624}
625
626constexpr Base base;
627constexpr Base base2(76);
628constexpr Derived derived;
629static_assert(derived.a == 76, "");
630static_assert(derived.b[2] == 's', "");
631static_assert(derived.c == 76 + 'e', "");
632static_assert(derived.q == 123, "");
633static_assert(derived.r == 76, "");
634static_assert(&derived.r == &derived.a, ""); // expected-error {{}}
635
636static_assert(!(derived == base), "");
637static_assert(derived == base2, "");
638
639constexpr Bottom &bot1 = (Base&)derived;
640constexpr Bottom &bot2 = (Base2&)derived;
641static_assert(&bot1 != &bot2, "");
642
643constexpr Bottom *pb1 = (Base*)&derived;
644constexpr Bottom *pb2 = (Base2*)&derived;
645static_assert(pb1 != pb2, "");
646static_assert(pb1 == &bot1, "");
647static_assert(pb2 == &bot2, "");
648
649constexpr Base2 &fail = (Base2&)bot1; // expected-error {{constant expression}}
650constexpr Base &fail2 = (Base&)*pb2; // expected-error {{constant expression}}
651constexpr Base2 &ok2 = (Base2&)bot2;
652static_assert(&ok2 == &derived, "");
653
654constexpr Base2 *pfail = (Base2*)pb1; // expected-error {{constant expression}}
655constexpr Base *pfail2 = (Base*)&bot2; // expected-error {{constant expression}}
656constexpr Base2 *pok2 = (Base2*)pb2;
657static_assert(pok2 == &derived, "");
658static_assert(&ok2 == pok2, "");
659static_assert((Base2*)(Derived*)(Base*)pb1 == pok2, "");
660static_assert((Derived*)(Base*)pb1 == (Derived*)pok2, "");
661
662constexpr Base *nullB = 42 - 6 * 7;
663static_assert((Bottom*)nullB == 0, "");
664static_assert((Derived*)nullB == 0, "");
665static_assert((void*)(Bottom*)nullB == (void*)(Derived*)nullB, "");
666
667}
668
669namespace Temporaries {
670
671struct S {
672  constexpr S() {}
673  constexpr int f();
674};
675struct T : S {
676  constexpr T(int n) : S(), n(n) {}
677  int n;
678};
679constexpr int S::f() {
680  // 'this' must be the postfix-expression in a class member access expression,
681  // so we can't just use
682  //   return static_cast<T*>(this)->n;
683  return this->*(int(S::*))&T::n;
684}
685// The T temporary is implicitly cast to an S subobject, but we can recover the
686// T full-object via a base-to-derived cast, or a derived-to-base-casted member
687// pointer.
688static_assert(T(3).f() == 3, "");
689
690constexpr int f(const S &s) {
691  return static_cast<const T&>(s).n;
692}
693constexpr int n = f(T(5));
694static_assert(f(T(5)) == 5, "");
695
696}
697
698namespace Union {
699
700union U {
701  int a;
702  int b;
703};
704
705constexpr U u[4] = { { .a = 0 }, { .b = 1 }, { .a = 2 }, { .b = 3 } }; // expected-warning 4{{extension}}
706static_assert(u[0].a == 0, "");
707static_assert(u[0].b, ""); // expected-error {{constant expression}}
708static_assert(u[1].b == 1, "");
709static_assert((&u[1].b)[1] == 2, ""); // expected-error {{constant expression}}
710static_assert(*(&(u[1].b) + 1 + 1) == 3, ""); // expected-error {{constant expression}}
711static_assert((&(u[1]) + 1 + 1)->b == 3, "");
712
713}
714
715namespace MemberPointer {
716  struct A {
717    constexpr A(int n) : n(n) {}
718    int n;
719    constexpr int f() { return n + 3; }
720  };
721  constexpr A a(7);
722  static_assert(A(5).*&A::n == 5, "");
723  static_assert((&a)->*&A::n == 7, "");
724  static_assert((A(8).*&A::f)() == 11, "");
725  static_assert(((&a)->*&A::f)() == 10, "");
726
727  struct B : A {
728    constexpr B(int n, int m) : A(n), m(m) {}
729    int m;
730    constexpr int g() { return n + m + 1; }
731  };
732  constexpr B b(9, 13);
733  static_assert(B(4, 11).*&A::n == 4, "");
734  static_assert(B(4, 11).*&B::m == 11, "");
735  static_assert(B(4, 11).*(int(A::*))&B::m == 11, "");
736  static_assert((&b)->*&A::n == 9, "");
737  static_assert((&b)->*&B::m == 13, "");
738  static_assert((&b)->*(int(A::*))&B::m == 13, "");
739  static_assert((B(4, 11).*&A::f)() == 7, "");
740  static_assert((B(4, 11).*&B::g)() == 16, "");
741  static_assert((B(4, 11).*(int(A::*)()const)&B::g)() == 16, "");
742  static_assert(((&b)->*&A::f)() == 12, "");
743  static_assert(((&b)->*&B::g)() == 23, "");
744  static_assert(((&b)->*(int(A::*)()const)&B::g)() == 23, "");
745
746  struct S {
747    constexpr S(int m, int n, int (S::*pf)() const, int S::*pn) :
748      m(m), n(n), pf(pf), pn(pn) {}
749    constexpr S() : m(), n(), pf(&S::f), pn(&S::n) {}
750
751    constexpr int f() { return this->*pn; }
752    virtual int g() const;
753
754    int m, n;
755    int (S::*pf)() const;
756    int S::*pn;
757  };
758
759  constexpr int S::*pm = &S::m;
760  constexpr int S::*pn = &S::n;
761  constexpr int (S::*pf)() const = &S::f;
762  constexpr int (S::*pg)() const = &S::g;
763
764  constexpr S s(2, 5, &S::f, &S::m);
765
766  static_assert((s.*&S::f)() == 2, "");
767  static_assert((s.*s.pf)() == 2, "");
768
769  template<int n> struct T : T<n-1> {};
770  template<> struct T<0> { int n; };
771  template<> struct T<30> : T<29> { int m; };
772
773  T<17> t17;
774  T<30> t30;
775
776  constexpr int (T<10>::*deepn) = &T<0>::n;
777  static_assert(&(t17.*deepn) == &t17.n, "");
778
779  constexpr int (T<15>::*deepm) = (int(T<10>::*))&T<30>::m;
780  constexpr int *pbad = &(t17.*deepm); // expected-error {{constant expression}}
781  static_assert(&(t30.*deepm) == &t30.m, "");
782
783  constexpr T<5> *p17_5 = &t17;
784  constexpr T<13> *p17_13 = (T<13>*)p17_5;
785  constexpr T<23> *p17_23 = (T<23>*)p17_13; // expected-error {{constant expression}}
786  static_assert(&(p17_5->*(int(T<3>::*))deepn) == &t17.n, "");
787  static_assert(&(p17_13->*deepn) == &t17.n, "");
788  constexpr int *pbad2 = &(p17_13->*(int(T<9>::*))deepm); // expected-error {{constant expression}}
789
790  constexpr T<5> *p30_5 = &t30;
791  constexpr T<23> *p30_23 = (T<23>*)p30_5;
792  constexpr T<13> *p30_13 = p30_23;
793  static_assert(&(p30_5->*(int(T<3>::*))deepn) == &t30.n, "");
794  static_assert(&(p30_13->*deepn) == &t30.n, "");
795  static_assert(&(p30_23->*deepn) == &t30.n, "");
796  static_assert(&(p30_5->*(int(T<2>::*))deepm) == &t30.m, "");
797  static_assert(&(((T<17>*)p30_13)->*deepm) == &t30.m, "");
798  static_assert(&(p30_23->*deepm) == &t30.m, "");
799}
800
801namespace ArrayBaseDerived {
802
803  struct Base {
804    constexpr Base() {}
805    int n = 0;
806  };
807  struct Derived : Base {
808    constexpr Derived() {}
809    constexpr const int *f() { return &n; }
810  };
811
812  constexpr Derived a[10];
813  constexpr Derived *pd3 = const_cast<Derived*>(&a[3]);
814  constexpr Base *pb3 = const_cast<Derived*>(&a[3]);
815  static_assert(pb3 == pd3, "");
816
817  // pb3 does not point to an array element.
818  constexpr Base *pb4 = pb3 + 1; // ok, one-past-the-end pointer.
819  constexpr int pb4n = pb4->n; // expected-error {{constant expression}}
820  constexpr Base *err_pb5 = pb3 + 2; // FIXME: reject this.
821  constexpr int err_pb5n = err_pb5->n; // expected-error {{constant expression}}
822  constexpr Base *err_pb2 = pb3 - 1; // FIXME: reject this.
823  constexpr int err_pb2n = err_pb2->n; // expected-error {{constant expression}}
824  constexpr Base *pb3a = pb4 - 1;
825
826  // pb4 does not point to a Derived.
827  constexpr Derived *err_pd4 = (Derived*)pb4; // expected-error {{constant expression}}
828  constexpr Derived *pd3a = (Derived*)pb3a;
829  constexpr int pd3n = pd3a->n;
830
831  // pd3a still points to the Derived array.
832  constexpr Derived *pd6 = pd3a + 3;
833  static_assert(pd6 == &a[6], "");
834  constexpr Derived *pd9 = pd6 + 3;
835  constexpr Derived *pd10 = pd6 + 4;
836  constexpr int pd9n = pd9->n; // ok
837  constexpr int err_pd10n = pd10->n; // expected-error {{constant expression}}
838  constexpr int pd0n = pd10[-10].n;
839  constexpr int err_pdminus1n = pd10[-11].n; // expected-error {{constant expression}}
840
841  constexpr Base *pb9 = pd9;
842  constexpr const int *(Base::*pfb)() const =
843      static_cast<const int *(Base::*)() const>(&Derived::f);
844  static_assert((pb9->*pfb)() == &a[9].n, "");
845}
846
847namespace Complex {
848
849class complex {
850  int re, im;
851public:
852  constexpr complex(int re = 0, int im = 0) : re(re), im(im) {}
853  constexpr complex(const complex &o) : re(o.re), im(o.im) {}
854  constexpr complex operator-() const { return complex(-re, -im); }
855  friend constexpr complex operator+(const complex &l, const complex &r) {
856    return complex(l.re + r.re, l.im + r.im);
857  }
858  friend constexpr complex operator-(const complex &l, const complex &r) {
859    return l + -r;
860  }
861  friend constexpr complex operator*(const complex &l, const complex &r) {
862    return complex(l.re * r.re - l.im * r.im, l.re * r.im + l.im * r.re);
863  }
864  friend constexpr bool operator==(const complex &l, const complex &r) {
865    return l.re == r.re && l.im == r.im;
866  }
867  constexpr bool operator!=(const complex &r) const {
868    return re != r.re || im != r.im;
869  }
870  constexpr int real() const { return re; }
871  constexpr int imag() const { return im; }
872};
873
874constexpr complex i = complex(0, 1);
875constexpr complex k = (3 + 4*i) * (6 - 4*i);
876static_assert(complex(1,0).real() == 1, "");
877static_assert(complex(1,0).imag() == 0, "");
878static_assert(((complex)1).imag() == 0, "");
879static_assert(k.real() == 34, "");
880static_assert(k.imag() == 12, "");
881static_assert(k - 34 == 12*i, "");
882static_assert((complex)1 == complex(1), "");
883static_assert((complex)1 != complex(0, 1), "");
884static_assert(complex(1) == complex(1), "");
885static_assert(complex(1) != complex(0, 1), "");
886constexpr complex makeComplex(int re, int im) { return complex(re, im); }
887static_assert(makeComplex(1,0) == complex(1), "");
888static_assert(makeComplex(1,0) != complex(0, 1), "");
889
890class complex_wrap : public complex {
891public:
892  constexpr complex_wrap(int re, int im = 0) : complex(re, im) {}
893  constexpr complex_wrap(const complex_wrap &o) : complex(o) {}
894};
895
896static_assert((complex_wrap)1 == complex(1), "");
897static_assert((complex)1 != complex_wrap(0, 1), "");
898static_assert(complex(1) == complex_wrap(1), "");
899static_assert(complex_wrap(1) != complex(0, 1), "");
900constexpr complex_wrap makeComplexWrap(int re, int im) {
901  return complex_wrap(re, im);
902}
903static_assert(makeComplexWrap(1,0) == complex(1), "");
904static_assert(makeComplexWrap(1,0) != complex(0, 1), "");
905
906}
907