clang/test/SemaCXX/warn-zero-nullptr.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify %s -isystem %S/Inputs -Wzero-as-null-pointer-constant -std=c++11
   2 // RUN: %clang_cc1 -fsyntax-only -verify %s -isystem %S/Inputs -DSYSTEM_WARNINGS -Wzero-as-null-pointer-constant -Wsystem-headers -std=c++11
   3
   4 #include <warn-zero-nullptr.h>
   5
   6 #define MACRO (0)
   7 #define MCRO(x) (x)
   8
   9 struct S {};
  10
  11 int (S::*mp0) = nullptr;
  12 void (*fp0)() = nullptr;
  13 void* p0 = nullptr;
  14
  15 int (S::*mp1) = 0; // expected-warning{{zero as null pointer constant}}
  16 void (*fp1)() = 0; // expected-warning{{zero as null pointer constant}}
  17 void* p1 = 0; // expected-warning{{zero as null pointer constant}}
  18
  19 // NULL is an integer constant expression, so warn on it too:
  20 void* p2 = __null; // expected-warning{{zero as null pointer constant}}
  21 void (*fp2)() = __null; // expected-warning{{zero as null pointer constant}}
  22 int (S::*mp2) = __null; // expected-warning{{zero as null pointer constant}}
  23
  24 void f0(void* v = MACRO); // expected-warning{{zero as null pointer constant}}
  25 void f1(void* v = NULL); // expected-warning{{zero as null pointer constant}}
  26 void f2(void* v = MCRO(0)); // expected-warning{{zero as null pointer constant}}
  27 void f3(void* v = MCRO(NULL)); // expected-warning{{zero as null pointer constant}}
  28 void f4(void* v = 0); // expected-warning{{zero as null pointer constant}}
  29 void f5(void* v);
  30
  31 void g() {
  32   f1(0); // expected-warning{{zero as null pointer constant}}
  33 }
  34
  35 // Warn on these too. Matches gcc and arguably makes sense.
  36 void* pp = (decltype(nullptr))0; // expected-warning{{zero as null pointer constant}}
  37 void* pp2 = static_cast<decltype(nullptr)>(0); // expected-warning{{zero as null pointer constant}}
  38
  39 // Shouldn't warn.
  40 namespace pr34362 {
  41 struct A { operator int*() { return nullptr; } };
  42 void func() { if (nullptr == A()) {} }
  43 void func2() { if ((nullptr) == A()) {} }
  44 }
  45
  46 template <typename T> void TmplFunc0(T var) {}
  47 void Func0Test() {
  48   TmplFunc0<int>(0);
  49   TmplFunc0<int*>(0); // expected-warning {{zero as null pointer constant}}
  50   TmplFunc0<void*>(0); // expected-warning {{zero as null pointer constant}}
  51 }
  52
  53 // FIXME: this one probably should not warn.
  54 template <typename T> void TmplFunc1(int a, T default_value = 0) {} // expected-warning{{zero as null pointer constant}} expected-warning{{zero as null pointer constant}}
  55 void FuncTest() {
  56   TmplFunc1<int>(0);
  57   TmplFunc1<int*>(0); // expected-note {{in instantiation of default function argument expression for 'TmplFunc1<int *>' required here}}
  58   TmplFunc1<void*>(0);  // expected-note {{in instantiation of default function argument expression for 'TmplFunc1<void *>' required here}}
  59 }
  60
  61 template<typename T>
  62 class TemplateClass0 {
  63  public:
  64   explicit TemplateClass0(T var) {}
  65 };
  66 void TemplateClass0Test() {
  67   TemplateClass0<int> a(0);
  68   TemplateClass0<int*> b(0); // expected-warning {{zero as null pointer constant}}
  69   TemplateClass0<void*> c(0); // expected-warning {{zero as null pointer constant}}
  70 }
  71
  72 template<typename T>
  73 class TemplateClass1 {
  74  public:
  75 // FIXME: this one should *NOT* warn.
  76   explicit TemplateClass1(int a, T default_value = 0) {} // expected-warning{{zero as null pointer constant}} expected-warning{{zero as null pointer constant}}
  77 };
  78 void IgnoreSubstTemplateType1() {
  79   TemplateClass1<int> a(1);
  80   TemplateClass1<int*> b(1); // expected-note {{in instantiation of default function argument expression for 'TemplateClass1<int *>' required here}}
  81   TemplateClass1<void*> c(1); // expected-note {{in instantiation of default function argument expression for 'TemplateClass1<void *>' required here}}
  82 }
  83
  84 #ifndef SYSTEM_WARNINGS
  85 // Do not warn on *any* other macros from system headers, even if they
  86 // expand to/their expansion contains NULL.
  87 void* sys_init = SYSTEM_MACRO;
  88 void* sys_init2 = OTHER_SYSTEM_MACRO;
  89 #else
  90 void* sys_init = SYSTEM_MACRO; // expected-warning {{zero as null pointer constant}}
  91 void* sys_init2 = OTHER_SYSTEM_MACRO; // expected-warning {{zero as null pointer constant}}
  92 #endif