<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/143509>143509</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Typo correction should be smarter about context
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            enhancement,
            clang:frontend,
            quality-of-implementation,
            clang:diagnostics
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          AaronBallman
      </td>
    </tr>
</table>

<pre>
    Currently, typo correction has very little intelligence about the context of the typo being corrected. As a result, we fail to suggest corrections as well as we could. For example:

This case fails to recognize we're in a context where we expect one of a handful of keywords:
```
struct S {
  S() = defaul;
};
```
https://godbolt.org/z/o4snPEGve
(The same applies in many other circumstances; we should have a general mechanism that filters keywords by context.)

This case fails to recognize a type is invalid (but only in C) and suggests we replace `lock` by `long`:
```
void func() {
  long x;
 x = (lock);
}
```
https://godbolt.org/z/cxbjbE1bP

This case fails to recognize that only a type is valid:
```
int lang;
int main() {
 (void)(ling)12;
}
```
https://godbolt.org/z/hc3rnrbKz

I expect more examples exist. The thrust of the request is to make typo correction a bit more situationally aware whenever possible.
</pre>
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