| Issue |
84324
|
| Summary |
make iterator checks in `modernize-use-auto` optional
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
firewave
|
The suggestions of this check might undermine the constness of iterators as a type explicitly specified as `const_iterator` might result in `iterator` instead if the container is not `const`.
```cpp
#include <map>
std::map<int, int> cb();
void f()
{
std::map<int, int> m = cb();
std::map<int, int>::const_iterator I = m.begin();
}
```
```
<source>:8:5: warning: use auto when declaring iterators [modernize-use-auto]
8 | std::map<int, int>::const_iterator I = m.begin();
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| auto
```
https://godbolt.org/z/7Gnr9d6ad
In the example it was not possible to modify the container if you add subsequent code. But if you introduce `auto` it is made possible.
This can be partially mitigated starting with C++11 by using `cbegin()` and `cend()`. (This seems like a candidate for a check in itself). `misc-const-correctness` might also be helpful in some cases.
Unfortunately there is no `cfind()` for containers like `std::map` so to mitigate those cases you have to use `std::as_const()` which is not available until C++17. (Also a candidate for a separate check).
So it would be helpful if you could disable the iterator part of this check. Or improve the check to only suggest cases where the resulting type behind `auto` might not be change/ambiguous.
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