| Issue |
141858
|
| Summary |
bad compilation with default arguments in clang 20
|
| Labels |
clang
|
| Assignees |
|
| Reporter |
rockwotj
|
https://godbolt.org/z/5s4GazKEP
```
#include <print>
#include <numeric>
#include <vector>
#include <string>
struct foo {std::string bar;};
const std::vector<foo> foos = {{"1"}, {"2"}, {"3"}};
size_t count(const std::vector<foo>& input = foos) {
size_t c = 0;
for (const foo& f : input) {
c += f.bar.size();
}
return c;
}
int main() {
std::print("answer 1: {}\n", count());
std::print("answer 2: {}\n", count({{"1"}, {"2"}}));
std::print("answer 3: {}\n", count());
}
```
When compiled in clang 20 we get 3 printed 3 times, while in clang 19 we get 3, 2, 3 printed. I suspect some kind of over-aggressive optimization is assuming the input to this function is always `foos`.
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