https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116731
Bug ID: 116731
Summary: Incorrect behavior of -Wrange-loop-construct in GCC 14
Product: gcc
Version: 14.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: sunil.dora1988 at gmail dot com
Target Milestone: ---
It appears that the warning by -Wrange-loop-construct is triggered incorrectly
for certain loop constructs.
Consider the below example :
#include <array>
#include <cstdint>
#include <iostream>
#include <set>
#include <string>
#include <string_view>
#include <utility>
#include <vector>
static std::string val{"vale"};
int main() {
const std::vector arr{std::pair<std::string_view, int>{val, 1}};
for (const auto [text, val] : arr) {
std::cout << text << val;
}
return 0;
}
=============
g++ -pipe -W -Wall -Wextra -pedantic -g -O -c -o test.o test.cpp
test.cpp: In function ‘int main()’:
test.cpp:14:21: warning: loop variable ‘<structured bindings>’ creates a copy
from type ‘const std::pair<std::basic_string_view<char>, int>’
[-Wrange-loop-construct]
14 | for (const auto [text, val] : arr) {
| ^~~~~~~~~~~
test.cpp:14:21: note: use reference type to prevent copying
14 | for (const auto [text, val] : arr) {
| ^~~~~~~~~~~
| &
g++ -g -o test test.o
================
It seems that GCC/G++ might be checking for trivial copyability rather than
trivial copy-constructibility, which could be contributing to the issue.
