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-rw-r--r--clang/test/SemaCXX/constant-expression-cxx11.cpp1250
1 files changed, 1250 insertions, 0 deletions
diff --git a/clang/test/SemaCXX/constant-expression-cxx11.cpp b/clang/test/SemaCXX/constant-expression-cxx11.cpp
new file mode 100644
index 0000000..9f80e71
--- /dev/null
+++ b/clang/test/SemaCXX/constant-expression-cxx11.cpp
@@ -0,0 +1,1250 @@
+// RUN: %clang_cc1 -triple i686-linux -Wno-string-plus-int -fsyntax-only -verify -std=c++11 -pedantic %s -Wno-comment
+
+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() { 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;
+
+}
+
+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 which 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 which 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 which 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 which 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), "");
+
+}
+
+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 which 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 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() { return n; }
+};
+struct ArrayRVal {
+ constexpr ArrayRVal() {}
+ ArrayElem elems[10];
+};
+static_assert(ArrayRVal().elems[3].f() == 0, "");
+
+}
+
+namespace DependentValues {
+
+struct I { int n; typedef I V[10]; };
+I::V x, y;
+template<bool B> struct S {
+ int k;
+ void f() {
+ I::V &cells = B ? x : y;
+ I &i = cells[k];
+ switch (i.n) {}
+ }
+};
+
+}
+
+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(); // expected-error {{constant expression}} expected-note {{reference to temporary is not a constant expression}} expected-note {{temporary created here}}
+// 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;
+ int n;
+ double d;
+ int arr[5];
+ void *p;
+};
+
+constexpr AggregateInit agg1 = { "hello"[0] };
+
+static_assert(strcmp_ce(&agg1.c, "hello") == 0, "");
+static_assert(agg1.n == 0, "");
+static_assert(agg1.d == 0.0, "");
+static_assert(agg1.arr[-1] == 0, ""); // expected-error {{constant expression}} expected-note {{cannot refer to element -1}}
+static_assert(agg1.arr[0] == 0, "");
+static_assert(agg1.arr[4] == 0, "");
+static_assert(agg1.arr[5] == 0, ""); // expected-error {{constant expression}} expected-note {{read of dereferenced one-past-the-end}}
+static_assert(agg1.p == nullptr, "");
+
+static constexpr const unsigned char uc[] = { "foo" };
+static_assert(uc[0] == 'f', "");
+static_assert(uc[3] == 0, "");
+
+namespace SimpleDerivedClass {
+
+struct B {
+ constexpr B(int n) : a(n) {}
+ int a;
+};
+struct D : B {
+ constexpr D(int n) : B(n) {}
+};
+constexpr D d(3);
+static_assert(d.a == 3, "");
+
+}
+
+struct Bottom { constexpr Bottom() {} };
+struct Base : Bottom {
+ constexpr Base(int a = 42, const char *b = "test") : a(a), b(b) {}
+ int a;
+ const char *b;
+};
+struct Base2 : Bottom {
+ constexpr Base2(const int &r) : r(r) {}
+ int q = 123;
+ const int &r;
+};
+struct Derived : Base, Base2 {
+ constexpr Derived() : Base(76), Base2(a) {}
+ int c = r + b[1];
+};
+
+constexpr bool operator==(const Base &a, const Base &b) {
+ return a.a == b.a && strcmp_ce(a.b, b.b) == 0;
+}
+
+constexpr Base base;
+constexpr Base base2(76);
+constexpr Derived derived;
+static_assert(derived.a == 76, "");
+static_assert(derived.b[2] == 's', "");
+static_assert(derived.c == 76 + 'e', "");
+static_assert(derived.q == 123, "");
+static_assert(derived.r == 76, "");
+static_assert(&derived.r == &derived.a, "");
+
+static_assert(!(derived == base), "");
+static_assert(derived == base2, "");
+
+constexpr Bottom &bot1 = (Base&)derived;
+constexpr Bottom &bot2 = (Base2&)derived;
+static_assert(&bot1 != &bot2, "");
+
+constexpr Bottom *pb1 = (Base*)&derived;
+constexpr Bottom *pb2 = (Base2*)&derived;
+static_assert(&pb1 != &pb2, "");
+static_assert(pb1 == &bot1, "");
+static_assert(pb2 == &bot2, "");
+
+constexpr Base2 &fail = (Base2&)bot1; // expected-error {{constant expression}} expected-note {{cannot cast object of dynamic type 'const Class::Derived' to type 'Class::Base2'}}
+constexpr Base &fail2 = (Base&)*pb2; // expected-error {{constant expression}} expected-note {{cannot cast object of dynamic type 'const Class::Derived' to type 'Class::Base'}}
+constexpr Base2 &ok2 = (Base2&)bot2;
+static_assert(&ok2 == &derived, "");
+
+constexpr Base2 *pfail = (Base2*)pb1; // expected-error {{constant expression}} expected-note {{cannot cast object of dynamic type 'const Class::Derived' to type 'Class::Base2'}}
+constexpr Base *pfail2 = (Base*)&bot2; // expected-error {{constant expression}} expected-note {{cannot cast object of dynamic type 'const Class::Derived' to type 'Class::Base'}}
+constexpr Base2 *pok2 = (Base2*)pb2;
+static_assert(pok2 == &derived, "");
+static_assert(&ok2 == pok2, "");
+static_assert((Base2*)(Derived*)(Base*)pb1 == pok2, "");
+static_assert((Derived*)(Base*)pb1 == (Derived*)pok2, "");
+
+constexpr Base *nullB = 42 - 6 * 7;
+static_assert((Bottom*)nullB == 0, "");
+static_assert((Derived*)nullB == 0, "");
+static_assert((void*)(Bottom*)nullB == (void*)(Derived*)nullB, "");
+
+namespace ConversionOperators {
+
+struct T {
+ constexpr T(int n) : k(5*n - 3) {}
+ constexpr operator int() { return k; }
+ int k;
+};
+
+struct S {
+ constexpr S(int n) : k(2*n + 1) {}
+ constexpr operator int() { return k; }
+ constexpr operator T() { return T(k); }
+ int k;
+};
+
+constexpr bool check(T a, T b) { return a == b.k; }
+
+static_assert(S(5) == 11, "");
+static_assert(check(S(5), 11), "");
+
+}
+
+}
+
+namespace Temporaries {
+
+struct S {
+ constexpr S() {}
+ constexpr int f();
+};
+struct T : S {
+ constexpr T(int n) : S(), n(n) {}
+ int n;
+};
+constexpr int S::f() {
+ // 'this' must be the postfix-expression in a class member access expression,
+ // so we can't just use
+ // return static_cast<T*>(this)->n;
+ return this->*(int(S::*))&T::n;
+}
+// The T temporary is implicitly cast to an S subobject, but we can recover the
+// T full-object via a base-to-derived cast, or a derived-to-base-casted member
+// pointer.
+static_assert(T(3).f() == 3, "");
+
+constexpr int f(const S &s) {
+ return static_cast<const T&>(s).n;
+}
+constexpr int n = f(T(5));
+static_assert(f(T(5)) == 5, "");
+
+constexpr bool b(int n) { return &n; }
+static_assert(b(0), "");
+
+}
+
+namespace Union {
+
+union U {
+ int a;
+ int b;
+};
+
+constexpr U u[4] = { { .a = 0 }, { .b = 1 }, { .a = 2 }, { .b = 3 } }; // expected-warning 4{{C99 feature}}
+static_assert(u[0].a == 0, "");
+static_assert(u[0].b, ""); // expected-error {{constant expression}} expected-note {{read of member 'b' of union with active member 'a'}}
+static_assert(u[1].b == 1, "");
+static_assert((&u[1].b)[1] == 2, ""); // expected-error {{constant expression}} expected-note {{read of dereferenced one-past-the-end pointer}}
+static_assert(*(&(u[1].b) + 1 + 1) == 3, ""); // expected-error {{constant expression}} expected-note {{cannot refer to element 2 of non-array object}}
+static_assert((&(u[1]) + 1 + 1)->b == 3, "");
+
+constexpr U v = {};
+static_assert(v.a == 0, "");
+
+union Empty {};
+constexpr Empty e = {};
+
+// Make sure we handle trivial copy constructors for unions.
+constexpr U x = {42};
+constexpr U y = x;
+static_assert(y.a == 42, "");
+static_assert(y.b == 42, ""); // expected-error {{constant expression}} expected-note {{'b' of union with active member 'a'}}
+
+}
+
+namespace MemberPointer {
+ struct A {
+ constexpr A(int n) : n(n) {}
+ int n;
+ constexpr int f() { return n + 3; }
+ };
+ constexpr A a(7);
+ static_assert(A(5).*&A::n == 5, "");
+ static_assert((&a)->*&A::n == 7, "");
+ static_assert((A(8).*&A::f)() == 11, "");
+ static_assert(((&a)->*&A::f)() == 10, "");
+
+ struct B : A {
+ constexpr B(int n, int m) : A(n), m(m) {}
+ int m;
+ constexpr int g() { return n + m + 1; }
+ };
+ constexpr B b(9, 13);
+ static_assert(B(4, 11).*&A::n == 4, "");
+ static_assert(B(4, 11).*&B::m == 11, "");
+ static_assert(B(4, 11).*(int(A::*))&B::m == 11, "");
+ static_assert((&b)->*&A::n == 9, "");
+ static_assert((&b)->*&B::m == 13, "");
+ static_assert((&b)->*(int(A::*))&B::m == 13, "");
+ static_assert((B(4, 11).*&A::f)() == 7, "");
+ static_assert((B(4, 11).*&B::g)() == 16, "");
+ static_assert((B(4, 11).*(int(A::*)()const)&B::g)() == 16, "");
+ static_assert(((&b)->*&A::f)() == 12, "");
+ static_assert(((&b)->*&B::g)() == 23, "");
+ static_assert(((&b)->*(int(A::*)()const)&B::g)() == 23, "");
+
+ struct S {
+ constexpr S(int m, int n, int (S::*pf)() const, int S::*pn) :
+ m(m), n(n), pf(pf), pn(pn) {}
+ constexpr S() : m(), n(), pf(&S::f), pn(&S::n) {}
+
+ constexpr int f() { return this->*pn; }
+ virtual int g() const;
+
+ int m, n;
+ int (S::*pf)() const;
+ int S::*pn;
+ };
+
+ constexpr int S::*pm = &S::m;
+ constexpr int S::*pn = &S::n;
+ constexpr int (S::*pf)() const = &S::f;
+ constexpr int (S::*pg)() const = &S::g;
+
+ constexpr S s(2, 5, &S::f, &S::m);
+
+ static_assert((s.*&S::f)() == 2, "");
+ static_assert((s.*s.pf)() == 2, "");
+
+ static_assert(pf == &S::f, "");
+ static_assert(pf == s.*&S::pf, "");
+ static_assert(pm == &S::m, "");
+ static_assert(pm != pn, "");
+ static_assert(s.pn != pn, "");
+ static_assert(s.pn == pm, "");
+ static_assert(pg != nullptr, "");
+ static_assert(pf != nullptr, "");
+ static_assert((int S::*)nullptr == nullptr, "");
+ static_assert(pg == pg, ""); // expected-error {{constant expression}} expected-note {{comparison of pointer to virtual member function 'g' has unspecified value}}
+ static_assert(pf != pg, ""); // expected-error {{constant expression}} expected-note {{comparison of pointer to virtual member function 'g' has unspecified value}}
+
+ template<int n> struct T : T<n-1> {};
+ template<> struct T<0> { int n; };
+ template<> struct T<30> : T<29> { int m; };
+
+ T<17> t17;
+ T<30> t30;
+
+ constexpr int (T<10>::*deepn) = &T<0>::n;
+ static_assert(&(t17.*deepn) == &t17.n, "");
+ static_assert(deepn == &T<2>::n, "");
+
+ constexpr int (T<15>::*deepm) = (int(T<10>::*))&T<30>::m;
+ constexpr int *pbad = &(t17.*deepm); // expected-error {{constant expression}}
+ static_assert(&(t30.*deepm) == &t30.m, "");
+ static_assert(deepm == &T<50>::m, "");
+ static_assert(deepm != deepn, "");
+
+ constexpr T<5> *p17_5 = &t17;
+ constexpr T<13> *p17_13 = (T<13>*)p17_5;
+ constexpr T<23> *p17_23 = (T<23>*)p17_13; // expected-error {{constant expression}} expected-note {{cannot cast object of dynamic type 'T<17>' to type 'T<23>'}}
+ static_assert(&(p17_5->*(int(T<3>::*))deepn) == &t17.n, "");
+ static_assert(&(p17_13->*deepn) == &t17.n, "");
+ constexpr int *pbad2 = &(p17_13->*(int(T<9>::*))deepm); // expected-error {{constant expression}}
+
+ constexpr T<5> *p30_5 = &t30;
+ constexpr T<23> *p30_23 = (T<23>*)p30_5;
+ constexpr T<13> *p30_13 = p30_23;
+ static_assert(&(p30_5->*(int(T<3>::*))deepn) == &t30.n, "");
+ static_assert(&(p30_13->*deepn) == &t30.n, "");
+ static_assert(&(p30_23->*deepn) == &t30.n, "");
+ static_assert(&(p30_5->*(int(T<2>::*))deepm) == &t30.m, "");
+ static_assert(&(((T<17>*)p30_13)->*deepm) == &t30.m, "");
+ static_assert(&(p30_23->*deepm) == &t30.m, "");
+
+ struct Base { int n; };
+ template<int N> struct Mid : Base {};
+ struct Derived : Mid<0>, Mid<1> {};
+ static_assert(&Mid<0>::n == &Mid<1>::n, "");
+ static_assert((int Derived::*)(int Mid<0>::*)&Mid<0>::n !=
+ (int Derived::*)(int Mid<1>::*)&Mid<1>::n, "");
+ static_assert(&Mid<0>::n == (int Mid<0>::*)&Base::n, "");
+}
+
+namespace ArrayBaseDerived {
+
+ struct Base {
+ constexpr Base() {}
+ int n = 0;
+ };
+ struct Derived : Base {
+ constexpr Derived() {}
+ constexpr const int *f() { return &n; }
+ };
+
+ constexpr Derived a[10];
+ constexpr Derived *pd3 = const_cast<Derived*>(&a[3]);
+ constexpr Base *pb3 = const_cast<Derived*>(&a[3]);
+ static_assert(pb3 == pd3, "");
+
+ // pb3 does not point to an array element.
+ constexpr Base *pb4 = pb3 + 1; // ok, one-past-the-end pointer.
+ constexpr int pb4n = pb4->n; // expected-error {{constant expression}} expected-note {{cannot access field of pointer past the end}}
+ constexpr Base *err_pb5 = pb3 + 2; // expected-error {{constant expression}} expected-note {{cannot refer to element 2}} expected-note {{here}}
+ constexpr int err_pb5n = err_pb5->n; // expected-error {{constant expression}} expected-note {{initializer of 'err_pb5' is not a constant expression}}
+ constexpr Base *err_pb2 = pb3 - 1; // expected-error {{constant expression}} expected-note {{cannot refer to element -1}} expected-note {{here}}
+ constexpr int err_pb2n = err_pb2->n; // expected-error {{constant expression}} expected-note {{initializer of 'err_pb2'}}
+ constexpr Base *pb3a = pb4 - 1;
+
+ // pb4 does not point to a Derived.
+ constexpr Derived *err_pd4 = (Derived*)pb4; // expected-error {{constant expression}} expected-note {{cannot access derived class of pointer past the end}}
+ constexpr Derived *pd3a = (Derived*)pb3a;
+ constexpr int pd3n = pd3a->n;
+
+ // pd3a still points to the Derived array.
+ constexpr Derived *pd6 = pd3a + 3;
+ static_assert(pd6 == &a[6], "");
+ constexpr Derived *pd9 = pd6 + 3;
+ constexpr Derived *pd10 = pd6 + 4;
+ constexpr int pd9n = pd9->n; // ok
+ constexpr int err_pd10n = pd10->n; // expected-error {{constant expression}} expected-note {{cannot access base class of pointer past the end}}
+ constexpr int pd0n = pd10[-10].n;
+ constexpr int err_pdminus1n = pd10[-11].n; // expected-error {{constant expression}} expected-note {{cannot refer to element -1 of}}
+
+ constexpr Base *pb9 = pd9;
+ constexpr const int *(Base::*pfb)() const =
+ static_cast<const int *(Base::*)() const>(&Derived::f);
+ static_assert((pb9->*pfb)() == &a[9].n, "");
+}
+
+namespace Complex {
+
+class complex {
+ int re, im;
+public:
+ constexpr complex(int re = 0, int im = 0) : re(re), im(im) {}
+ constexpr complex(const complex &o) : re(o.re), im(o.im) {}
+ constexpr complex operator-() const { return complex(-re, -im); }
+ friend constexpr complex operator+(const complex &l, const complex &r) {
+ return complex(l.re + r.re, l.im + r.im);
+ }
+ friend constexpr complex operator-(const complex &l, const complex &r) {
+ return l + -r;
+ }
+ friend constexpr complex operator*(const complex &l, const complex &r) {
+ return complex(l.re * r.re - l.im * r.im, l.re * r.im + l.im * r.re);
+ }
+ friend constexpr bool operator==(const complex &l, const complex &r) {
+ return l.re == r.re && l.im == r.im;
+ }
+ constexpr bool operator!=(const complex &r) const {
+ return re != r.re || im != r.im;
+ }
+ constexpr int real() const { return re; }
+ constexpr int imag() const { return im; }
+};
+
+constexpr complex i = complex(0, 1);
+constexpr complex k = (3 + 4*i) * (6 - 4*i);
+static_assert(complex(1,0).real() == 1, "");
+static_assert(complex(1,0).imag() == 0, "");
+static_assert(((complex)1).imag() == 0, "");
+static_assert(k.real() == 34, "");
+static_assert(k.imag() == 12, "");
+static_assert(k - 34 == 12*i, "");
+static_assert((complex)1 == complex(1), "");
+static_assert((complex)1 != complex(0, 1), "");
+static_assert(complex(1) == complex(1), "");
+static_assert(complex(1) != complex(0, 1), "");
+constexpr complex makeComplex(int re, int im) { return complex(re, im); }
+static_assert(makeComplex(1,0) == complex(1), "");
+static_assert(makeComplex(1,0) != complex(0, 1), "");
+
+class complex_wrap : public complex {
+public:
+ constexpr complex_wrap(int re, int im = 0) : complex(re, im) {}
+ constexpr complex_wrap(const complex_wrap &o) : complex(o) {}
+};
+
+static_assert((complex_wrap)1 == complex(1), "");
+static_assert((complex)1 != complex_wrap(0, 1), "");
+static_assert(complex(1) == complex_wrap(1), "");
+static_assert(complex_wrap(1) != complex(0, 1), "");
+constexpr complex_wrap makeComplexWrap(int re, int im) {
+ return complex_wrap(re, im);
+}
+static_assert(makeComplexWrap(1,0) == complex(1), "");
+static_assert(makeComplexWrap(1,0) != complex(0, 1), "");
+
+}
+
+namespace PR11595 {
+ struct A { constexpr bool operator==(int x) { return true; } };
+ struct B { B(); A& x; };
+ static_assert(B().x == 3, ""); // expected-error {{constant expression}} expected-note {{non-literal type 'PR11595::B' cannot be used in a constant expression}}
+
+ constexpr bool f(int k) { // expected-error {{constexpr function never produces a constant expression}}
+ return B().x == k; // expected-note {{non-literal type 'PR11595::B' cannot be used in a constant expression}}
+ }
+}
+
+namespace ExprWithCleanups {
+ struct A { A(); ~A(); int get(); };
+ constexpr int get(bool FromA) { return FromA ? A().get() : 1; }
+ constexpr int n = get(false);
+}
+
+namespace Volatile {
+
+volatile constexpr int n1 = 0; // expected-note {{here}}
+volatile const int n2 = 0; // expected-note {{here}}
+int n3 = 37; // expected-note {{declared here}}
+
+constexpr int m1 = n1; // expected-error {{constant expression}} expected-note {{read of volatile-qualified type 'const volatile int'}}
+constexpr int m2 = n2; // expected-error {{constant expression}} expected-note {{read of volatile-qualified type 'const volatile int'}}
+constexpr int m1b = const_cast<const int&>(n1); // expected-error {{constant expression}} expected-note {{read of volatile object 'n1'}}
+constexpr int m2b = const_cast<const int&>(n2); // expected-error {{constant expression}} expected-note {{read of volatile object 'n2'}}
+
+struct T { int n; };
+const T t = { 42 }; // expected-note {{declared here}}
+
+constexpr int f(volatile int &&r) {
+ return r; // expected-note {{read of volatile-qualified type 'volatile int'}}
+}
+constexpr int g(volatile int &&r) {
+ return const_cast<int&>(r); // expected-note {{read of volatile temporary is not allowed in a constant expression}}
+}
+struct S {
+ int j : f(0); // expected-error {{constant expression}} expected-note {{in call to 'f(0)'}}
+ int k : g(0); // expected-error {{constant expression}} expected-note {{temporary created here}} expected-note {{in call to 'g(0)'}}
+ int l : n3; // expected-error {{constant expression}} expected-note {{read of non-const variable}}
+ int m : t.n; // expected-error {{constant expression}} expected-note {{read of non-constexpr variable}}
+};
+
+}
+
+namespace ExternConstexpr {
+ extern constexpr int n = 0;
+ extern constexpr int m; // expected-error {{constexpr variable declaration must be a definition}}
+ void f() {
+ extern constexpr int i; // expected-error {{constexpr variable declaration must be a definition}}
+ constexpr int j = 0;
+ constexpr int k; // expected-error {{default initialization of an object of const type}}
+ }
+}
+
+namespace ComplexConstexpr {
+ constexpr _Complex float test1 = {};
+ constexpr _Complex float test2 = {1};
+ constexpr _Complex double test3 = {1,2};
+ constexpr _Complex int test4 = {4};
+ constexpr _Complex int test5 = 4;
+ constexpr _Complex int test6 = {5,6};
+ typedef _Complex float fcomplex;
+ constexpr fcomplex test7 = fcomplex();
+
+ constexpr const double &t2r = __real test3;
+ constexpr const double &t2i = __imag test3;
+ static_assert(&t2r + 1 == &t2i, "");
+ static_assert(t2r == 1.0, "");
+ static_assert(t2i == 2.0, "");
+ constexpr const double *t2p = &t2r;
+ static_assert(t2p[-1] == 0.0, ""); // expected-error {{constant expr}} expected-note {{cannot refer to element -1 of array of 2 elements}}
+ static_assert(t2p[0] == 1.0, "");
+ static_assert(t2p[1] == 2.0, "");
+ static_assert(t2p[2] == 0.0, ""); // expected-error {{constant expr}} expected-note {{one-past-the-end pointer}}
+ static_assert(t2p[3] == 0.0, ""); // expected-error {{constant expr}} expected-note {{cannot refer to element 3 of array of 2 elements}}
+ constexpr _Complex float *p = 0;
+ constexpr float pr = __real *p; // expected-error {{constant expr}} expected-note {{cannot access real component of null}}
+ constexpr float pi = __imag *p; // expected-error {{constant expr}} expected-note {{cannot access imaginary component of null}}
+ constexpr const _Complex double *q = &test3 + 1;
+ constexpr double qr = __real *q; // expected-error {{constant expr}} expected-note {{cannot access real component of pointer past the end}}
+ constexpr double qi = __imag *q; // expected-error {{constant expr}} expected-note {{cannot access imaginary component of pointer past the end}}
+
+ static_assert(__real test6 == 5, "");
+ static_assert(__imag test6 == 6, "");
+ static_assert(&__imag test6 == &__real test6 + 1, "");
+}
+
+namespace InstantiateCaseStmt {
+ template<int x> constexpr int f() { return x; }
+ template<int x> int g(int c) { switch(c) { case f<x>(): return 1; } return 0; }
+ int gg(int c) { return g<4>(c); }
+}
+
+namespace ConvertedConstantExpr {
+ extern int &m;
+ extern int &n;
+
+ constexpr int k = 4;
+ int &m = const_cast<int&>(k);
+
+ // If we have nothing more interesting to say, ensure we don't produce a
+ // useless note and instead just point to the non-constant subexpression.
+ enum class E {
+ em = m,
+ en = n, // expected-error {{not a constant expression}}
+ eo = (m +
+ n // expected-error {{not a constant expression}}
+ ),
+ eq = reinterpret_cast<int>((int*)0) // expected-error {{not a constant expression}} expected-note {{reinterpret_cast}}
+ };
+}
+
+namespace IndirectField {
+ struct S {
+ struct { // expected-warning {{GNU extension}}
+ union {
+ struct { // expected-warning {{GNU extension}}
+ int a;
+ int b;
+ };
+ int c;
+ };
+ int d;
+ };
+ union {
+ int e;
+ int f;
+ };
+ constexpr S(int a, int b, int d, int e) : a(a), b(b), d(d), e(e) {}
+ constexpr S(int c, int d, int f) : c(c), d(d), f(f) {}
+ };
+
+ constexpr S s1(1, 2, 3, 4);
+ constexpr S s2(5, 6, 7);
+
+ // FIXME: The diagnostics here do a very poor job of explaining which unnamed
+ // member is active and which is requested.
+ static_assert(s1.a == 1, "");
+ static_assert(s1.b == 2, "");
+ static_assert(s1.c == 0, ""); // expected-error {{constant expression}} expected-note {{union with active member}}
+ static_assert(s1.d == 3, "");
+ static_assert(s1.e == 4, "");
+ static_assert(s1.f == 0, ""); // expected-error {{constant expression}} expected-note {{union with active member}}
+
+ static_assert(s2.a == 0, ""); // expected-error {{constant expression}} expected-note {{union with active member}}
+ static_assert(s2.b == 0, ""); // expected-error {{constant expression}} expected-note {{union with active member}}
+ static_assert(s2.c == 5, "");
+ static_assert(s2.d == 6, "");
+ static_assert(s2.e == 0, ""); // expected-error {{constant expression}} expected-note {{union with active member}}
+ static_assert(s2.f == 7, "");
+}
+
+// DR1405: don't allow reading mutable members in constant expressions.
+namespace MutableMembers {
+ struct MM {
+ mutable int n; // expected-note 3{{declared here}}
+ } constexpr mm = { 4 };
+ constexpr int mmn = mm.n; // expected-error {{constant expression}} expected-note {{read of mutable member 'n' is not allowed in a constant expression}}
+ int x = (mm.n = 1, 3);
+ constexpr int mmn2 = mm.n; // expected-error {{constant expression}} expected-note {{read of mutable member 'n' is not allowed in a constant expression}}
+
+ // Here's one reason why allowing this would be a disaster...
+ template<int n> struct Id { int k = n; };
+ int f() {
+ constexpr MM m = { 0 };
+ ++m.n;
+ return Id<m.n>().k; // expected-error {{not a constant expression}} expected-note {{read of mutable member 'n' is not allowed in a constant expression}}
+ }
+
+ struct A { int n; };
+ struct B { mutable A a; }; // expected-note {{here}}
+ struct C { B b; };
+ constexpr C c[3] = {};
+ constexpr int k = c[1].b.a.n; // expected-error {{constant expression}} expected-note {{mutable}}
+}
+
+namespace Fold {
+
+ // This macro forces its argument to be constant-folded, even if it's not
+ // otherwise a constant expression.
+ #define fold(x) (__builtin_constant_p(x) ? (x) : (x))
+
+ constexpr int n = (int)(char*)123; // expected-error {{constant expression}} expected-note {{reinterpret_cast}}
+ constexpr int m = fold((int)(char*)123); // ok
+ static_assert(m == 123, "");
+
+ #undef fold
+
+}
+
+namespace DR1454 {
+
+constexpr const int &f(const int &n) { return n; }
+constexpr int k1 = f(0); // ok
+
+struct Wrap {
+ const int &value;
+};
+constexpr const Wrap &g(const Wrap &w) { return w; }
+constexpr int k2 = g({0}).value; // ok
+
+constexpr const int &i = 0; // expected-error {{constant expression}} expected-note {{temporary}} expected-note 2{{here}}
+constexpr const int j = i; // expected-error {{constant expression}} expected-note {{initializer of 'i' is not a constant expression}}
+
+}
+
+namespace RecursiveOpaqueExpr {
+ template<typename Iter>
+ constexpr auto LastNonzero(Iter p, Iter q) -> decltype(+*p) {
+ return p != q ? (LastNonzero(p+1, q) ?: *p) : 0; // expected-warning {{GNU}}
+ }
+
+ constexpr int arr1[] = { 1, 0, 0, 3, 0, 2, 0, 4, 0, 0 };
+ static_assert(LastNonzero(begin(arr1), end(arr1)) == 4, "");
+
+ constexpr int arr2[] = { 1, 0, 0, 3, 0, 2, 0, 4, 0, 5 };
+ static_assert(LastNonzero(begin(arr2), end(arr2)) == 5, "");
+}
+
+namespace VLASizeof {
+
+ void f(int k) {
+ int arr[k]; // expected-warning {{C99}}
+ constexpr int n = 1 +
+ sizeof(arr) // expected-error {{constant expression}}
+ * 3;
+ }
+}
+
+namespace CompoundLiteral {
+ // FIXME:
+ // We don't model the semantics of this correctly: the compound literal is
+ // represented as a prvalue in the AST, but actually behaves like an lvalue.
+ // We treat the compound literal as a temporary and refuse to produce a
+ // pointer to it. This is OK: we're not required to treat this as a constant
+ // in C++, and in C we model compound literals as lvalues.
+ constexpr int *p = (int*)(int[1]){0}; // expected-warning {{C99}} expected-error {{constant expression}} expected-note 2{{temporary}}
+}
+
+namespace Vector {
+ typedef int __attribute__((vector_size(16))) VI4;
+ constexpr VI4 f(int n) {
+ return VI4 { n * 3, n + 4, n - 5, n / 6 };
+ }
+ constexpr auto v1 = f(10);
+
+ typedef double __attribute__((vector_size(32))) VD4;
+ constexpr VD4 g(int n) {
+ return (VD4) { n / 2.0, n + 1.5, n - 5.4, n * 0.9 }; // expected-warning {{C99}}
+ }
+ constexpr auto v2 = g(4);
+}
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