<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/129498>129498</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Clang tidy modernize-use-starts-ends-with suggest incorrect fixit if rfind (valid for find also) use not null terminated range
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          belobrov-andrey
      </td>
    </tr>
</table>

<pre>
    Code sample:

```
 const std::string testString = "testString";

 static constexpr std::array<char, 2> testCharArray = {static_cast<char>(0xBD),
 static_cast<char>(0x92)}; // Array is not null terminated

 bool found = testString.rfind(testCharArray.data(), 0, testCharArray.size()) == 0;
```

Clang tidy suggests to change string with rfind to 
```
bool found = testString.starts_with(testCharArray.data()); // This is UB since testCharArray is not null terminated
```
But it is not valid since count argument of rfind is ignored.

It looks like it should be either no fix at all if count if passed to rfind/find, or fix should take into account count value:
```
testString.starts_with({testCharArray.data(), testCharArray.size()});
```
This code will created string_view with correct size of array and code should work correctly.
</pre>
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