clang/test/SemaCXX/i-c-e-cxx.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify -pedantic %s
   2 // RUN: %clang_cc1 -fsyntax-only -verify -pedantic -std=gnu++98 %s
   3 // RUN: %clang_cc1 -fsyntax-only -verify -pedantic -std=gnu++11 %s
   4
   5 // C++-specific tests for integral constant expressions.
   6
   7 const int c = 10;
   8 int ar[c];
   9
  10 struct X0 {
  11   static const int value = static_cast<int>(4.0);
  12 };
  13
  14 void f() {
  15   if (const int value = 17) {
  16     int array[value];
  17   }
  18 }
  19
  20 int a() {
  21   const int t=t; // expected-note {{declared here}}
  22
  23   switch(1) { // do not warn that 1 is not a case value;
  24               // 't' might have been expected to evalaute to 1
  25     case t:; // expected-note {{initializer of 't' is not a constant expression}}
  26 #if __cplusplus <= 199711L
  27     // expected-error@-2 {{not an integral constant expression}}
  28 #else
  29     // expected-error@-4 {{case value is not a constant expression}}
  30 #endif
  31   }
  32 }
  33
  34 // PR6206:  out-of-line definitions are legit
  35 namespace pr6206 {
  36   class Foo {
  37   public:
  38     static const int kBar;
  39   };
  40
  41   const int Foo::kBar = 20;
  42
  43   char Test() {
  44     char str[Foo::kBar];
  45     str[0] = '0';
  46     return str[0];
  47   }
  48 }
  49
  50 // PR6373:  default arguments don't count.
  51 void pr6373(const unsigned x = 0) {
  52   unsigned max = 80 / x;
  53 }
  54
  55
  56 namespace rdar9204520 {
  57
  58 struct A {
  59   static const int B = int(0.75 * 1000 * 1000);
  60 #if __cplusplus <= 199711L
  61   // expected-warning@-2 {{not a constant expression; folding it to a constant is a GNU extension}}
  62 #endif
  63 };
  64
  65 int foo() { return A::B; }
  66 }
  67
  68 // PR11040
  69 const int x = 10;
  70 int* y = reinterpret_cast<const char&>(x); // expected-error {{cannot initialize}}
  71
  72 // This isn't an integral constant expression, but make sure it folds anyway.
  73 struct PR8836 { char _; long long a; };
  74 #if __cplusplus <= 199711L
  75 // expected-warning@-2 {{'long long' is a C++11 extension}}
  76 #endif
  77
  78 int PR8836test[(__typeof(sizeof(int)))&reinterpret_cast<const volatile char&>((((PR8836*)0)->a))];
  79 // expected-warning@-1 0-1{{variable length arrays in C++ are a Clang extension}} expected-warning@-1 {{folded to constant array as an extension}}
  80 // expected-note@-2 {{cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression}}
  81
  82 const int nonconst = 1.0;
  83 #if __cplusplus <= 199711L
  84 // expected-note@-2 {{declared here}}
  85 #endif
  86 int arr[nonconst];
  87 #if __cplusplus <= 199711L
  88 // expected-warning@-2 0-1{{variable length arrays in C++ are a Clang extension}} expected-warning@-2 {{folded to constant array as an extension}}
  89 // expected-note@-3 {{initializer of 'nonconst' is not a constant expression}}
  90 #endif
  91
  92 const int castfloat = static_cast<int>(1.0);
  93 int arr2[castfloat]; // ok