xref: /external/clang/test/SemaCXX/constant-expression-cxx11.cpp

// RUN: %clang_cc1 -triple i686-linux -Wno-string-plus-int -Wno-pointer-arith -Wno-zero-length-array -fsyntax-only -fcxx-exceptions -verify -std=c++11 -pedantic %s -Wno-comment -Wno-tautological-pointer-compare -Wno-bool-conversion

namespace StaticAssertFoldTest {

int x;
static_assert(++x, "test"); // expected-error {{not an integral constant expression}}
static_assert(false, "test"); // expected-error {{test}}

}

typedef decltype(sizeof(char)) size_t;

template<typename T> constexpr T id(const T &t) { return t; }
template<typename T> constexpr T min(const T &a, const T &b) {
  return a < b ? a : b;
}
template<typename T> constexpr T max(const T &a, const T &b) {
  return a < b ? b : a;
}
template<typename T, size_t N> constexpr T *begin(T (&xs)[N]) { return xs; }
template<typename T, size_t N> constexpr T *end(T (&xs)[N]) { return xs + N; }

struct MemberZero {
  constexpr int zero() const { return 0; }
};

namespace DerivedToVBaseCast {

  struct U { int n; };
  struct V : U { int n; };
  struct A : virtual V { int n; };
  struct Aa { int n; };
  struct B : virtual A, Aa {};
  struct C : virtual A, Aa {};
  struct D : B, C {};

  D d;
  constexpr B *p = &d;
  constexpr C *q = &d;

  static_assert((void*)p != (void*)q, "");
  static_assert((A*)p == (A*)q, "");
  static_assert((Aa*)p != (Aa*)q, "");

  constexpr B &pp = d;
  constexpr C &qq = d;
  static_assert((void*)&pp != (void*)&qq, "");
  static_assert(&(A&)pp == &(A&)qq, "");
  static_assert(&(Aa&)pp != &(Aa&)qq, "");

  constexpr V *v = p;
  constexpr V *w = q;
  constexpr V *x = (A*)p;
  static_assert(v == w, "");
  static_assert(v == x, "");

  static_assert((U*)&d == p, "");
  static_assert((U*)&d == q, "");
  static_assert((U*)&d == v, "");
  static_assert((U*)&d == w, "");
  static_assert((U*)&d == x, "");

  struct X {};
  struct Y1 : virtual X {};
  struct Y2 : X {};
  struct Z : Y1, Y2 {};
  Z z;
  static_assert((X*)(Y1*)&z != (X*)(Y2*)&z, "");
}

namespace ConstCast {

constexpr int n1 = 0;
constexpr int n2 = const_cast<int&>(n1);
constexpr int *n3 = const_cast<int*>(&n1);
constexpr int n4 = *const_cast<int*>(&n1);
constexpr const int * const *n5 = const_cast<const int* const*>(&n3);
constexpr int **n6 = const_cast<int**>(&n3);
constexpr int n7 = **n5;
constexpr int n8 = **n6;

// const_cast from prvalue to xvalue.
struct A { int n; };
constexpr int n9 = (const_cast<A&&>(A{123})).n;
static_assert(n9 == 123, "");

}

namespace TemplateArgumentConversion {
  template<int n> struct IntParam {};

  using IntParam0 = IntParam<0>;
  using IntParam0 = IntParam<id(0)>;
  using IntParam0 = IntParam<MemberZero().zero>; // expected-error {{did you mean to call it with no arguments?}}
}

namespace CaseStatements {
  void f(int n) {
    switch (n) {
    case MemberZero().zero: // expected-error {{did you mean to call it with no arguments?}} expected-note {{previous}}
    case id(0): // expected-error {{duplicate case value '0'}}
      return;
    }
  }
}

extern int &Recurse1;
int &Recurse2 = Recurse1; // expected-note {{declared here}}
int &Recurse1 = Recurse2;
constexpr int &Recurse3 = Recurse2; // expected-error {{must be initialized by a constant expression}} expected-note {{initializer of 'Recurse2' is not a constant expression}}

extern const int RecurseA;
const int RecurseB = RecurseA; // expected-note {{declared here}}
const int RecurseA = 10;
constexpr int RecurseC = RecurseB; // expected-error {{must be initialized by a constant expression}} expected-note {{initializer of 'RecurseB' is not a constant expression}}

namespace MemberEnum {
  struct WithMemberEnum {
    enum E { A = 42 };
  } wme;

  static_assert(wme.A == 42, "");
}

namespace DefaultArguments {

const int z = int();
constexpr int Sum(int a = 0, const int &b = 0, const int *c = &z, char d = 0) {
  return a + b + *c + d;
}
const int four = 4;
constexpr int eight = 8;
constexpr const int twentyseven = 27;
static_assert(Sum() == 0, "");
static_assert(Sum(1) == 1, "");
static_assert(Sum(1, four) == 5, "");
static_assert(Sum(1, eight, &twentyseven) == 36, "");
static_assert(Sum(1, 2, &four, eight) == 15, "");

}

namespace Ellipsis {

// Note, values passed through an ellipsis can't actually be used.
constexpr int F(int a, ...) { return a; }
static_assert(F(0) == 0, "");
static_assert(F(1, 0) == 1, "");
static_assert(F(2, "test") == 2, "");
static_assert(F(3, &F) == 3, "");
int k = 0; // expected-note {{here}}
static_assert(F(4, k) == 3, ""); // expected-error {{constant expression}} expected-note {{read of non-const variable 'k'}}

}

namespace Recursion {
  constexpr int fib(int n) { return n > 1 ? fib(n-1) + fib(n-2) : n; }
  static_assert(fib(11) == 89, "");

  constexpr int gcd_inner(int a, int b) {
    return b == 0 ? a : gcd_inner(b, a % b);
  }
  constexpr int gcd(int a, int b) {
    return gcd_inner(max(a, b), min(a, b));
  }

  static_assert(gcd(1749237, 5628959) == 7, "");
}

namespace FunctionCast {
  // When folding, we allow functions to be cast to different types. Such
  // cast functions cannot be called, even if they're constexpr.
  constexpr int f() { return 1; }
  typedef double (*DoubleFn)();
  typedef int (*IntFn)();
  int a[(int)DoubleFn(f)()]; // expected-error {{variable length array}} expected-warning{{C99 feature}}
  int b[(int)IntFn(f)()];    // ok
}

namespace StaticMemberFunction {
  struct S {
    static constexpr int k = 42;
    static constexpr int f(int n) { return n * k + 2; }
  } s;

  constexpr int n = s.f(19);
  static_assert(S::f(19) == 800, "");
  static_assert(s.f(19) == 800, "");
  static_assert(n == 800, "");

  constexpr int (*sf1)(int) = &S::f;
  constexpr int (*sf2)(int) = &s.f;
  constexpr const int *sk = &s.k;
}

namespace ParameterScopes {

  const int k = 42;
  constexpr const int &ObscureTheTruth(const int &a) { return a; }
  constexpr const int &MaybeReturnJunk(bool b, const int a) { // expected-note 2{{declared here}}
    return ObscureTheTruth(b ? a : k);
  }
  static_assert(MaybeReturnJunk(false, 0) == 42, ""); // ok
  constexpr int a = MaybeReturnJunk(true, 0); // expected-error {{constant expression}} expected-note {{read of variable whose lifetime has ended}}

  constexpr const int MaybeReturnNonstaticRef(bool b, const int a) {
    return ObscureTheTruth(b ? a : k);
  }
  static_assert(MaybeReturnNonstaticRef(false, 0) == 42, ""); // ok
  constexpr int b = MaybeReturnNonstaticRef(true, 0); // ok

  constexpr int InternalReturnJunk(int n) {
    return MaybeReturnJunk(true, n); // expected-note {{read of variable whose lifetime has ended}}
  }
  constexpr int n3 = InternalReturnJunk(0); // expected-error {{must be initialized by a constant expression}} expected-note {{in call to 'InternalReturnJunk(0)'}}

  constexpr int LToR(int &n) { return n; }
  constexpr int GrabCallersArgument(bool which, int a, int b) {
    return LToR(which ? b : a);
  }
  static_assert(GrabCallersArgument(false, 1, 2) == 1, "");
  static_assert(GrabCallersArgument(true, 4, 8) == 8, "");

}

namespace Pointers {

  constexpr int f(int n, const int *a, const int *b, const int *c) {
    return n == 0 ? 0 : *a + f(n-1, b, c, a);
  }

  const int x = 1, y = 10, z = 100;
  static_assert(f(23, &x, &y, &z) == 788, "");

  constexpr int g(int n, int a, int b, int c) {
    return f(n, &a, &b, &c);
  }
  static_assert(g(23, x, y, z) == 788, "");

}

namespace FunctionPointers {

  constexpr int Double(int n) { return 2 * n; }
  constexpr int Triple(int n) { return 3 * n; }
  constexpr int Twice(int (*F)(int), int n) { return F(F(n)); }
  constexpr int Quadruple(int n) { return Twice(Double, n); }
  constexpr auto Select(int n) -> int (*)(int) {
    return n == 2 ? &Double : n == 3 ? &Triple : n == 4 ? &Quadruple : 0;
  }
  constexpr int Apply(int (*F)(int), int n) { return F(n); } // expected-note {{subexpression}}

  static_assert(1 + Apply(Select(4), 5) + Apply(Select(3), 7) == 42, "");

  constexpr int Invalid = Apply(Select(0), 0); // expected-error {{must be initialized by a constant expression}} expected-note {{in call to 'Apply(0, 0)'}}

}

namespace PointerComparison {

int x, y;
static_assert(&x == &y, "false"); // expected-error {{false}}
static_assert(&x != &y, "");
constexpr bool g1 = &x == &y;
constexpr bool g2 = &x != &y;
constexpr bool g3 = &x <= &y; // expected-error {{must be initialized by a constant expression}}
constexpr bool g4 = &x >= &y; // expected-error {{must be initialized by a constant expression}}
constexpr bool g5 = &x < &y; // expected-error {{must be initialized by a constant expression}}
constexpr bool g6 = &x > &y; // expected-error {{must be initialized by a constant expression}}

struct S { int x, y; } s;
static_assert(&s.x == &s.y, "false"); // expected-error {{false}}
static_assert(&s.x != &s.y, "");
static_assert(&s.x <= &s.y, "");
static_assert(&s.x >= &s.y, "false"); // expected-error {{false}}
static_assert(&s.x < &s.y, "");
static_assert(&s.x > &s.y, "false"); // expected-error {{false}}

static_assert(0 == &y, "false"); // expected-error {{false}}
static_assert(0 != &y, "");
constexpr bool n3 = 0 <= &y; // expected-error {{must be initialized by a constant expression}}
constexpr bool n4 = 0 >= &y; // expected-error {{must be initialized by a constant expression}}
constexpr bool n5 = 0 < &y; // expected-error {{must be initialized by a constant expression}}
constexpr bool n6 = 0 > &y; // expected-error {{must be initialized by a constant expression}}

static_assert(&x == 0, "false"); // expected-error {{false}}
static_assert(&x != 0, "");
constexpr bool n9 = &x <= 0; // expected-error {{must be initialized by a constant expression}}
constexpr bool n10 = &x >= 0; // expected-error {{must be initialized by a constant expression}}
constexpr bool n11 = &x < 0; // expected-error {{must be initialized by a constant expression}}
constexpr bool n12 = &x > 0; // expected-error {{must be initialized by a constant expression}}

static_assert(&x == &x, "");
static_assert(&x != &x, "false"); // expected-error {{false}}
static_assert(&x <= &x, "");
static_assert(&x >= &x, "");
static_assert(&x < &x, "false"); // expected-error {{false}}
static_assert(&x > &x, "false"); // expected-error {{false}}

constexpr S* sptr = &s;
constexpr bool dyncast = sptr == dynamic_cast<S*>(sptr); // expected-error {{constant expression}} expected-note {{dynamic_cast}}

struct U {};
struct Str {
  int a : dynamic_cast<S*>(sptr) == dynamic_cast<S*>(sptr); // \
    expected-warning {{not an integral constant expression}} \
    expected-note {{dynamic_cast is not allowed in a constant expression}}
  int b : reinterpret_cast<S*>(sptr) == reinterpret_cast<S*>(sptr); // \
    expected-warning {{not an integral constant expression}} \
    expected-note {{reinterpret_cast is not allowed in a constant expression}}
  int c : (S*)(long)(sptr) == (S*)(long)(sptr); // \
    expected-warning {{not an integral constant expression}} \
    expected-note {{cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression}}
  int d : (S*)(42) == (S*)(42); // \
    expected-warning {{not an integral constant expression}} \
    expected-note {{cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression}}
  int e : (Str*)(sptr) == (Str*)(sptr); // \
    expected-warning {{not an integral constant expression}} \
    expected-note {{cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression}}
  int f : &(U&)(*sptr) == &(U&)(*sptr); // \
    expected-warning {{not an integral constant expression}} \
    expected-note {{cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression}}
  int g : (S*)(void*)(sptr) == sptr; // \
    expected-warning {{not an integral constant expression}} \
    expected-note {{cast from 'void *' is not allowed in a constant expression}}
};

extern char externalvar[];
constexpr bool constaddress = (void *)externalvar == (void *)0x4000UL; // expected-error {{must be initialized by a constant expression}}
constexpr bool litaddress = "foo" == "foo"; // expected-error {{must be initialized by a constant expression}} expected-warning {{unspecified}}
static_assert(0 != "foo", "");

}

namespace MaterializeTemporary {

constexpr int f(const int &r) { return r; }
constexpr int n = f(1);

constexpr bool same(const int &a, const int &b) { return &a == &b; }
constexpr bool sameTemporary(const int &n) { return same(n, n); }

static_assert(n, "");
static_assert(!same(4, 4), "");
static_assert(same(n, n), "");
static_assert(sameTemporary(9), "");

struct A { int &&r; };
struct B { A &&a1; A &&a2; };

constexpr B b1 { { 1 }, { 2 } }; // expected-note {{temporary created here}}
static_assert(&b1.a1 != &b1.a2, "");
static_assert(&b1.a1.r != &b1.a2.r, ""); // expected-error {{constant expression}} expected-note {{outside the expression that created the temporary}}

constexpr B &&b2 { { 3 }, { 4 } }; // expected-note {{temporary created here}}
static_assert(&b1 != &b2, "");
static_assert(&b1.a1 != &b2.a1, ""); // expected-error {{constant expression}} expected-note {{outside the expression that created the temporary}}

constexpr thread_local B b3 { { 1 }, { 2 } }; // expected-error {{constant expression}} expected-note {{reference to temporary}} expected-note {{here}}
void foo() {
  constexpr static B b1 { { 1 }, { 2 } }; // ok
  constexpr thread_local B b2 { { 1 }, { 2 } }; // expected-error {{constant expression}} expected-note {{reference to temporary}} expected-note {{here}}
  constexpr B b3 { { 1 }, { 2 } }; // expected-error {{constant expression}} expected-note {{reference to temporary}} expected-note {{here}}
}

constexpr B &&b4 = ((1, 2), 3, 4, B { {10}, {{20}} }); // expected-warning 4{{unused}}
static_assert(&b4 != &b2, "");

// Proposed DR: copy-elision doesn't trigger lifetime extension.
constexpr B b5 = B{ {0}, {0} }; // expected-error {{constant expression}} expected-note {{reference to temporary}} expected-note {{here}}

namespace NestedNonStatic {
  // Proposed DR: for a reference constant expression to refer to a static
  // storage duration temporary, that temporary must itself be initialized
  // by a constant expression (a core constant expression is not enough).
  struct A { int &&r; };
  struct B { A &&a; };
  constexpr B a = { A{0} }; // ok
  constexpr B b = { A(A{0}) }; // expected-error {{constant expression}} expected-note {{reference to temporary}} expected-note {{here}}
}

namespace FakeInitList {
  struct init_list_3_ints { const int (&x)[3]; };
  struct init_list_2_init_list_3_ints { const init_list_3_ints (&x)[2]; };
  constexpr init_list_2_init_list_3_ints ils = { { { { 1, 2, 3 } }, { { 4, 5, 6 } } } };
}

}

constexpr int strcmp_ce(const char *p, const char *q) {
  return (!*p || *p != *q) ? *p - *q : strcmp_ce(p+1, q+1);
}

namespace StringLiteral {

template<typename Char>
constexpr int MangleChars(const Char *p) {
  return *p + 3 * (*p ? MangleChars(p+1) : 0);
}

static_assert(MangleChars("constexpr!") == 1768383, "");
static_assert(MangleChars(u8"constexpr!") == 1768383, "");
static_assert(MangleChars(L"constexpr!") == 1768383, "");
static_assert(MangleChars(u"constexpr!") == 1768383, "");
static_assert(MangleChars(U"constexpr!") == 1768383, "");

constexpr char c0 = "nought index"[0];
constexpr char c1 = "nice index"[10];
constexpr char c2 = "nasty index"[12]; // expected-error {{must be initialized by a constant expression}} expected-warning {{is past the end}} expected-note {{read of dereferenced one-past-the-end pointer}}
constexpr char c3 = "negative index"[-1]; // expected-error {{must be initialized by a constant expression}} expected-warning {{is before the beginning}} expected-note {{cannot refer to element -1 of array of 15 elements}}
constexpr char c4 = ((char*)(int*)"no reinterpret_casts allowed")[14]; // expected-error {{must be initialized by a constant expression}} expected-note {{cast that performs the conversions of a reinterpret_cast}}

constexpr const char *p = "test" + 2;
static_assert(*p == 's', "");

constexpr const char *max_iter(const char *a, const char *b) {
  return *a < *b ? b : a;
}
constexpr const char *max_element(const char *a, const char *b) {
  return (a+1 >= b) ? a : max_iter(a, max_element(a+1, b));
}

constexpr char str[] = "the quick brown fox jumped over the lazy dog";
constexpr const char *max = max_element(begin(str), end(str));
static_assert(*max == 'z', "");
static_assert(max == str + 38, "");

static_assert(strcmp_ce("hello world", "hello world") == 0, "");
static_assert(strcmp_ce("hello world", "hello clang") > 0, "");
static_assert(strcmp_ce("constexpr", "test") < 0, "");
static_assert(strcmp_ce("", " ") < 0, "");

struct S {
  int n : "foo"[4]; // expected-error {{constant expression}} expected-note {{read of dereferenced one-past-the-end pointer is not allowed in a constant expression}}
};

struct T {
  char c[6];
  constexpr T() : c{"foo"} {}
};
constexpr T t;

static_assert(t.c[0] == 'f', "");
static_assert(t.c[1] == 'o', "");
static_assert(t.c[2] == 'o', "");
static_assert(t.c[3] == 0, "");
static_assert(t.c[4] == 0, "");
static_assert(t.c[5] == 0, "");
static_assert(t.c[6] == 0, ""); // expected-error {{constant expression}} expected-note {{one-past-the-end}}

struct U {
  wchar_t chars[6];
  int n;
} constexpr u = { { L"test" }, 0 };
static_assert(u.chars[2] == L's', "");

struct V {
  char c[4];
  constexpr V() : c("hi!") {}
};
static_assert(V().c[1] == "i"[0], "");

namespace Parens {
  constexpr unsigned char a[] = ("foo"), b[] = {"foo"}, c[] = {("foo")},
                          d[4] = ("foo"), e[5] = {"foo"}, f[6] = {("foo")};
  static_assert(a[0] == 'f', "");
  static_assert(b[1] == 'o', "");
  static_assert(c[2] == 'o', "");
  static_assert(d[0] == 'f', "");
  static_assert(e[1] == 'o', "");
  static_assert(f[2] == 'o', "");
  static_assert(f[5] == 0, "");
  static_assert(f[6] == 0, ""); // expected-error {{constant expression}} expected-note {{one-past-the-end}}
}

}

namespace Array {

template<typename Iter>
constexpr auto Sum(Iter begin, Iter end) -> decltype(+*begin) {
  return begin == end ? 0 : *begin + Sum(begin+1, end);
}

constexpr int xs[] = { 1, 2, 3, 4, 5 };
constexpr int ys[] = { 5, 4, 3, 2, 1 };
constexpr int sum_xs = Sum(begin(xs), end(xs));
static_assert(sum_xs == 15, "");

constexpr int ZipFoldR(int (*F)(int x, int y, int c), int n,
                       const int *xs, const int *ys, int c) {
  return n ? F(
               *xs, // expected-note {{read of dereferenced one-past-the-end pointer}}
               *ys,
               ZipFoldR(F, n-1, xs+1, ys+1, c)) // \
      expected-note {{in call to 'ZipFoldR(&SubMul, 2, &xs[4], &ys[4], 1)'}} \
      expected-note {{in call to 'ZipFoldR(&SubMul, 1, &xs[5], &ys[5], 1)'}}
           : c;
}
constexpr int MulAdd(int x, int y, int c) { return x * y + c; }
constexpr int InnerProduct = ZipFoldR(MulAdd, 5, xs, ys, 0);
static_assert(InnerProduct == 35, "");

constexpr int SubMul(int x, int y, int c) { return (x - y) * c; }
constexpr int DiffProd = ZipFoldR(SubMul, 2, xs+3, ys+3, 1);
static_assert(DiffProd == 8, "");
static_assert(ZipFoldR(SubMul, 3, xs+3, ys+3, 1), ""); // \
      expected-error {{constant expression}} \
      expected-note {{in call to 'ZipFoldR(&SubMul, 3, &xs[3], &ys[3], 1)'}}

constexpr const int *p = xs + 3;
constexpr int xs4 = p[1]; // ok
constexpr int xs5 = p[2]; // expected-error {{constant expression}} expected-note {{read of dereferenced one-past-the-end pointer}}
constexpr int xs6 = p[3]; // expected-error {{constant expression}} expected-note {{cannot refer to element 6}}
constexpr int xs0 = p[-3]; // ok
constexpr int xs_1 = p[-4]; // expected-error {{constant expression}} expected-note {{cannot refer to element -1}}

constexpr int zs[2][2][2][2] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
static_assert(zs[0][0][0][0] == 1, "");
static_assert(zs[1][1][1][1] == 16, "");
static_assert(zs[0][0][0][2] == 3, ""); // expected-error {{constant expression}} expected-note {{read of dereferenced one-past-the-end pointer}}
static_assert((&zs[0][0][0][2])[-1] == 2, "");
static_assert(**(**(zs + 1) + 1) == 11, "");
static_assert(*(&(&(*(*&(&zs[2] - 1)[0] + 2 - 2))[2])[-1][-1] + 1) == 11, ""); // expected-error {{constant expression}} expected-note {{cannot refer to element -1 of array of 2 elements in a constant expression}}
static_assert(*(&(&(*(*&(&zs[2] - 1)[0] + 2 - 2))[2])[-1][2] - 2) == 11, "");
constexpr int err_zs_1_2_0_0 = zs[1][2][0][0]; // expected-error {{constant expression}} expected-note {{cannot access array element of pointer past the end}}

constexpr int fail(const int &p) {
  return (&p)[64]; // expected-note {{cannot refer to element 64 of array of 2 elements}}
}
static_assert(fail(*(&(&(*(*&(&zs[2] - 1)[0] + 2 - 2))[2])[-1][2] - 2)) == 11, ""); // \
expected-error {{static_assert expression is not an integral constant expression}} \
expected-note {{in call to 'fail(zs[1][0][1][0])'}}

constexpr int arr[40] = { 1, 2, 3, [8] = 4 }; // expected-warning {{C99 feature}}
constexpr int SumNonzero(const int *p) {
  return *p + (*p ? SumNonzero(p+1) : 0);
}
constexpr int CountZero(const int *p, const int *q) {
  return p == q ? 0 : (*p == 0) + CountZero(p+1, q);
}
static_assert(SumNonzero(arr) == 6, "");
static_assert(CountZero(arr, arr + 40) == 36, "");

struct ArrayElem {
  constexpr ArrayElem() : n(0) {}
  int n;
  constexpr int f() const { return n; }
};
struct ArrayRVal {
  constexpr ArrayRVal() {}
  ArrayElem elems[10];
};
static_assert(ArrayRVal().elems[3].f() == 0, "");

constexpr int selfref[2][2][2] = {
  selfref[1][1][1] + 1, selfref[0][0][0] + 1,
  selfref[1][0][1] + 1, selfref[0][1][0] + 1,
  selfref[1][0][0] + 1, selfref[0][1][1] + 1 };
static_assert(selfref[0][0][0] == 1, "");
static_assert(selfref[0][0][1] == 2, "");
static_assert(selfref[0][1][0] == 1, "");
static_assert(selfref[0][1][1] == 2, "");
static_assert(selfref[1][0][0] == 1, "");
static_assert(selfref[1][0][1] == 3, "");
static_assert(selfref[1][1][0] == 0, "");
static_assert(selfref[1][1][1] == 0, "");

struct TrivialDefCtor { int n; };
typedef TrivialDefCtor TDCArray[2][2];
static_assert(TDCArray{}[1][1].n == 0, "");

struct NonAggregateTDC : TrivialDefCtor {};
typedef NonAggregateTDC NATDCArray[2][2];
static_assert(NATDCArray{}[1][1].n == 0, "");

}

namespace DependentValues {

struct I { int n; typedef I V[10]; };
I::V x, y;
int g();
template<bool B, typename T> struct S : T {
  int k;
  void f() {
    I::V &cells = B ? x : y;
    I &i = cells[k];
    switch (i.n) {}

    // FIXME: We should be able to diagnose this.
    constexpr int n = g();

    constexpr int m = this->g(); // ok, could be constexpr
  }
};

}

namespace Class {

struct A { constexpr A(int a, int b) : k(a + b) {} int k; };
constexpr int fn(const A &a) { return a.k; }
static_assert(fn(A(4,5)) == 9, "");

struct B { int n; int m; } constexpr b = { 0, b.n }; // expected-warning {{uninitialized}}
struct C {
  constexpr C(C *this_) : m(42), n(this_->m) {} // ok
  int m, n;
};
struct D {
  C c;
  constexpr D() : c(&c) {}
};
static_assert(D().c.n == 42, "");

struct E {
  constexpr E() : p(&p) {}
  void *p;
};
constexpr const E &e1 = E();
// This is a constant expression if we elide the copy constructor call, and
// is not a constant expression if we don't! But we do, so it is.
constexpr E e2 = E();
static_assert(e2.p == &e2.p, "");
constexpr E e3;
static_assert(e3.p == &e3.p, "");

extern const class F f;
struct F {
  constexpr F() : p(&f.p) {}
  const void *p;
};
constexpr F f;

struct G {
  struct T {
    constexpr T(T *p) : u1(), u2(p) {}
    union U1 {
      constexpr U1() {}
      int a, b = 42;
    } u1;
    union U2 {
      constexpr U2(T *p) : c(p->u1.b) {}
      int c, d;
    } u2;
  } t;
  constexpr G() : t(&t) {}
} constexpr g;

static_assert(g.t.u1.a == 42, ""); // expected-error {{constant expression}} expected-note {{read of member 'a' of union with active member 'b'}}
static_assert(g.t.u1.b == 42, "");
static_assert(g.t.u2.c == 42, "");
static_assert(g.t.u2.d == 42, ""); // expected-error {{constant expression}} expected-note {{read of member 'd' of union with active member 'c'}}

struct S {
  int a, b;
  const S *p;
  double d;
  const char *q;

  constexpr S(int n, const S *p) : a(5), b(n), p(p), d(n), q("hello") {}
};

S global(43, &global);

static_assert(S(15, &global).b == 15, "");

constexpr bool CheckS(const S &s) {
  return s.a == 5 && s.b == 27 && s.p == &global && s.d == 27. && s.q[3] == 'l';
}
static_assert(CheckS(S(27, &global)), "");

struct Arr {
  char arr[3];
  constexpr Arr() : arr{'x', 'y', 'z'} {}
};
constexpr int hash(Arr &&a) {
  return a.arr[0] + a.arr[1] * 0x100 + a.arr[2] * 0x10000;
}
constexpr int k = hash(Arr());
static_assert(k == 0x007a7978, "");


struct AggregateInit {
  const char &c;