clang/test/SemaCXX/warn-unused-but-set-variables-cpp.cpp

   1 // RUN: %clang_cc1 -fblocks -fsyntax-only -Wunused-but-set-variable -verify %s
   2
   3 struct S {
   4   int i;
   5 };
   6
   7 struct __attribute__((warn_unused)) SWarnUnused {
   8   int j;
   9   void operator +=(int);
  10   void operator ++();
  11 };
  12
  13 int f0() {
  14   int y; // expected-warning{{variable 'y' set but not used}}
  15   y = 0;
  16
  17   int z __attribute__((unused));
  18   z = 0;
  19
  20   // In C++, don't warn for structs. (following gcc's behavior)
  21   struct S s;
  22   struct S t;
  23   s = t;
  24
  25   // Unless it's marked with the warn_unused attribute.
  26   struct SWarnUnused swu; // expected-warning{{variable 'swu' set but not used}}
  27   struct SWarnUnused swu2;
  28   swu = swu2;
  29
  30   int x;
  31   x = 0;
  32   return x + 5;
  33 }
  34
  35 void f1(void) {
  36   (void)^() {
  37     int y; // expected-warning{{variable 'y' set but not used}}
  38     y = 0;
  39
  40     int x;
  41     x = 0;
  42     return x;
  43   };
  44 }
  45
  46 void f2() {
  47   // Don't warn for either of these cases.
  48   constexpr int x = 2;
  49   const int y = 1;
  50   char a[x];
  51   char b[y];
  52 }
  53
  54 void f3(int n) {
  55   // Don't warn for overloaded compound assignment operators.
  56   SWarnUnused swu;
  57   swu += n;
  58 }
  59
  60 template<typename T> void f4(T n) {
  61   // Don't warn for (potentially) overloaded compound assignment operators in
  62   // template code.
  63   SWarnUnused swu;
  64   swu += n;
  65 }
  66
  67 template <typename T> void f5() {
  68   // Don't warn for overloaded pre/post operators in template code.
  69   SWarnUnused swu;
  70   ++swu;
  71 }