| Issue |
155146
|
| Summary |
Clang can't choose between operators int/bool for operator<
|
| Labels |
clang
|
| Assignees |
|
| Reporter |
Alcaro
|
```c++
struct eee {
operator int() const { return 5; }
operator bool() const { return true; }
};
int main(int argc, char** argv)
{
eee f;
if (f < 0) {}
}
```
https://godbolt.org/z/4Gnfo4Pqf
Expected: There is no operator<(bool,int), so choosing operator<(int,int) would require the fewest conversion operations, and should be chosen.
Actual: Prints a dozen candidate operator<, and thinks operator<(float,int) is the most relevant one.
```
<source>:9:8: error: use of overloaded operator '<' is ambiguous (with operand types 'eee' and 'int')
9 | if (f < 0) {}
| ~ ^ ~
<source>:9:8: note: because of ambiguity in conversion of 'eee' to 'float'
<source>:2:2: note: candidate function
2 | operator int() const { return 5; }
| ^
<source>:3:2: note: candidate function
3 | operator bool() const { return true; }
| ^
<source>:9:8: note: built-in candidate operator<(float, int)
9 | if (f < 0) {}
| ^
<source>:9:8: note: built-in candidate operator<(double, int)
<source>:9:8: note: built-in candidate operator<(long double, int)
<source>:9:8: note: built-in candidate operator<(__float128, int)
<source>:9:8: note: built-in candidate operator<(int, int)
<source>:9:8: note: built-in candidate operator<(long, int)
<source>:9:8: note: built-in candidate operator<(long long, int)
<source>:9:8: note: built-in candidate operator<(__int128, int)
<source>:9:8: note: built-in candidate operator<(unsigned int, int)
<source>:9:8: note: built-in candidate operator<(unsigned long, int)
<source>:9:8: note: built-in candidate operator<(unsigned long long, int)
<source>:9:8: note: built-in candidate operator<(unsigned __int128, int)
1 error generated.
```
I think this is a rejects-valid (GCC, MSVC, and my intuition all agree that operator int() should be chosen), but even if it's instead an accepts-invalid in the others, naming float in the error is rather unhelpful, isn't it?
(Bonus issue: Change to operator float(), and Clang prints an error naming 146 different operator<. I think that one is also rejects-valid, for the same reason. https://godbolt.org/z/Y8joWar89)
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