clang/test/SemaCXX/warn-dangling-local.cpp

   1 // RUN: %clang_cc1 -verify -std=c++11 -Wdangling-assignment-gsl %s
   2
   3 using T = int[];
   4
   5 void f() {
   6   int *p = &(int&)(int&&)0; // expected-warning {{temporary whose address is used as value of local variable 'p' will be destroyed at the end of the full-expression}}
   7   p =  &(int&)(int&&)0; // expected-warning {{object backing the pointer p will be destroyed at the end of the full-expression}}
   8
   9   int *q = (int *const &)T{1, 2, 3}; // expected-warning {{temporary whose address is used as value of local variable 'q' will be destroyed at the end of the full-expression}}
  10   q = (int *const &)T{1, 2, 3}; // expected-warning {{object backing the pointer q will be destroyed at the end of the full-expression}}
  11
  12   // FIXME: We don't warn here because the 'int*' temporary is not const, but
  13   // it also can't have actually changed since it was created, so we could
  14   // still warn.
  15   int *r = (int *&&)T{1, 2, 3};
  16
  17   // FIXME: The wording of this warning is not quite right. There are two
  18   // temporaries here: an 'int* const' temporary that points to the array, and
  19   // is lifetime-extended, and an array temporary that the pointer temporary
  20   // points to, which doesn't live long enough.
  21   int *const &s = (int *const &)T{1, 2, 3}; // expected-warning {{temporary bound to local reference 's' will be destroyed at the end of the full-expression}}
  22 }
  23
  24 // PR38355
  25 void g() {
  26   const int a[] = {a[0]};
  27   const int b[] = {a[0]};
  28 }
  29
  30 namespace std {
  31 // std::basic_string has a hard-coded gsl::owner attr.
  32 struct basic_string {
  33   const char* c_str();
  34 };
  35 }  // namespace std
  36 void test(const char* a) {
  37   // verify we're emitting the `-Wdangling-assignment-gsl` warning.
  38   a = std::basic_string().c_str(); // expected-warning {{object backing the pointer a will be destroyed at the end of the full-expression}}
  39 }