clang/test/SemaCXX/warn-uninitialized-const-reference.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -fcxx-exceptions -fexceptions -Wuninitialized-const-reference -verify %s
   2
   3 class A {
   4 public:
   5   int i;
   6   A(){};
   7   A(const A &a){};
   8   A(int i) {}
   9   bool operator!=(const A &);
  10 };
  11
  12 template <class T>
  13 void ignore_template(const T &) {}
  14 void ignore(const int &i) {}
  15 void dont_ignore_non_empty(const int &i) { ; } // Calling this won't silence the warning for you
  16 void dont_ignore_block(const int &i) {
  17   {}
  18 } // Calling this won't silence the warning for you
  19 void ignore_function_try_block_maybe_who_knows(const int &) try {
  20 } catch (...) {
  21 }
  22 A const_ref_use_A(const A &a);
  23 int const_ref_use(const int &i);
  24 A const_use_A(const A a);
  25 int const_use(const int i);
  26
  27 void f(int a) {
  28   int i;
  29   const_ref_use(i);             // expected-warning {{variable 'i' is uninitialized when passed as a const reference argument here}}
  30   int j = j + const_ref_use(j); // expected-warning {{variable 'j' is uninitialized when used within its own initialization}} expected-warning {{variable 'j' is uninitialized when passed as a const reference argument here}}
  31   A a1 = const_ref_use_A(a1);   // expected-warning {{variable 'a1' is uninitialized when passed as a const reference argument here}}
  32   int k = const_use(k);         // expected-warning {{variable 'k' is uninitialized when used within its own initialization}}
  33   A a2 = const_use_A(a2);       // expected-warning {{variable 'a2' is uninitialized when used within its own initialization}}
  34   A a3(const_ref_use_A(a3));    // expected-warning {{variable 'a3' is uninitialized when passed as a const reference argument here}}
  35   A a4 = a3 != a4;              // expected-warning {{variable 'a4' is uninitialized when used within its own initialization}} expected-warning {{variable 'a4' is uninitialized when passed as a const reference argument here}}
  36   int n = n;                    // expected-warning {{variable 'n' is uninitialized when used within its own initialization}}
  37   const_ref_use(n);
  38
  39   A a5;
  40   const_ref_use_A(a5);
  41
  42   int m;
  43   if (a < 42)
  44     m = 1;
  45   const_ref_use(m);
  46
  47   int l;
  48   ignore_template(l); // This is a pattern to avoid "unused variable" warnings (e.g. boost::ignore_unused).
  49   ignore(l);
  50   dont_ignore_non_empty(l); // expected-warning {{variable 'l' is uninitialized when passed as a const reference argument here}}
  51   int l1;
  52   dont_ignore_block(l1); // expected-warning {{variable 'l1' is uninitialized when passed as a const reference argument here}}
  53   int l2;
  54   ignore_function_try_block_maybe_who_knows(l2); // expected-warning {{variable 'l2' is uninitialized when passed as a const reference argument here}}
  55 }