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From: "dilyan.palauzov at aegee dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/114220] New: False positive warning: possibly dangling reference to a temporary [-Wdangling-reference] Date: Sun, 03 Mar 2024 08:26:20 +0000 [thread overview] Message-ID: <bug-114220-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114220 Bug ID: 114220 Summary: False positive warning: possibly dangling reference to a temporary [-Wdangling-reference] Product: gcc Version: 13.2.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: dilyan.palauzov at aegee dot org Target Milestone: --- Created attachment 57598 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57598&action=edit The inlined programme This code #include <string> #include <unordered_map> static const std::unordered_map<int, std::string> hashTable1 = {{2, "u"}}; static const std::unordered_map<std::string, std::string> hashTable2 = {{"u", "u"}}; const std::string& z1(int m); const std::string& z1(int m) { return hashTable1.at(m); } const std::string& z2(const std::string& m); const std::string& z2(const std::string& m) { return hashTable2.at(m); } const std::string& z3(); const std::string& z3() { return hashTable2.at("u"); } int main() { const std::string& b1 { z1(2) }; const std::string& b2 { z2("u") }; const std::string& b3 { z3() }; const std::string& f1 = hashTable1.at(2); const std::string& f2 = hashTable2.at("u"); printf("%s %s %s %s %s\n", b1.c_str(), b2.c_str(), f1.c_str(), f2.c_str(), b3.c_str()); } produces with g++ (GCC) 13.2.1 20240302: $ g++ -Wall -Wextra -o a a.cpp a.c: In function ‘int main()’: a.c:16:22: warning: possibly dangling reference to a temporary [-Wdangling-reference] 16 | const std::string& b2 { z2("u") }; | ^~ a.c:16:29: note: the temporary was destroyed at the end of the full expression ‘z2(std::__cxx11::basic_string<char>(((const char*)"u"), std::allocator<char>()))’ 16 | const std::string& b2 { z2("u") }; | ~~^~~~~ So std::string as first template parameter is problematic (b2), when only the second template parameter is relevant (b3), but int as first template parameter is fine (b1). I think this is a bug.
next reply other threads:[~2024-03-03 8:26 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-03-03 8:26 dilyan.palauzov at aegee dot org [this message] 2024-03-03 8:33 ` [Bug c++/114220] " pinskia at gcc dot gnu.org 2024-03-03 10:23 ` dilyan.palauzov at aegee dot org 2024-03-03 10:30 ` dilyan.palauzov at aegee dot org 2024-03-03 18:37 ` pinskia at gcc dot gnu.org 2024-03-04 9:07 ` xry111 at gcc dot gnu.org
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