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