<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/143688>143688</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Regression in follow-on diagnostic behavior after removing delayed typos
        </td>
    </tr>

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

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

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

<pre>
    With the removal of delayed typos, Clang now emits some follow-on diagnostics it previously did not. The crux of the issue was that delayed typos would result in a `RecoveryExpr` being made, but without delayed typos, sometimes the invalid statement is dropped entirely now. This leads to follow-on diagnostics, like the following:
```
constexpr int error() { // pre-cxx23-error {{no return statement in constexpr function}}
  return invalid;
}
```
The previous AST was:
```
`-FunctionDecl 0x15abc3dacd8 <C:\Users\aballman\OneDrive - Intel Corporation\Desktop\test.cpp:1:1, col:39> col:15 constexpr foo 'int ()' implicit-inline
  `-CompoundStmt 0x15abc3dae40 <col:21, col:39>
    `-ReturnStmt 0x15abc3dae30 <col:23, col:30>
      `-RecoveryExpr 0x15abc3dae10 <col:30> '<dependent type>' contains-errors lvalue
```
and the current AST is now:
```
`-FunctionDecl 0x2958326acd8 <C:\Users\aballman\OneDrive - Intel Corporation\Desktop\test.cpp:1:1, col:39> col:15 invalid constexpr foo 'int ()' implicit-inline
  `-CompoundStmt 0x2958326adf8 <col:21, col:39>
```
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzEVU2P2zYQ_TX0ZSBDIvVhH3TwamOgpwKbFD1T5MhiQ5EqOfLa_76g7M06m6DooUAAGTZAvZn35g2fZYzm5BBbVj2x6nkjFxp9aA8yePckrZ2k2_ReX9s_DY1AI0LAyZ-lBT-ARiuvqIGus4-Md9BZ6U7g_CvgZChC9BPC4K31r5l3oI08OR_JqAiGYA54Nn6J9graaHCetvBlRFBhuaTyqZuJcUF4lRFolPR9R3j1i9UQMC6WwDiQwOr8BZU_Y7h-usyB1Tn0aNwJJqkxMewXgldDo1_oR_qJLpkJ4621O0trNESShBM6AhNBBz_PqAEdmYD2msQm1iaCRakjkP-54FTfmq-4lr69YdyJiQPLD6zO709-UN5FwsscwDgCDMEHxneM74E1T8D4kfFjmlymLhcusvWFdMSaJ-chIC3BPVJ28F5xWJwi4x1rntOTH-ANcNfKxFOis549kkquvLkFh89fkiE_Umd1nh3vLZ5RWcgvRSV7JbRUegdMdF0CVd0fEUNkVSf724axqvvd4XMwZ4QMfnOEFjofZh_kSrfqnjF-JT-zqiOMtFXzzMShWD-8A-UtEwexZ-LT_XdRPcr2Hhhv0jxvo2S8ATPN1ihDmXHWOFyHkQR0fpr94vRnmuhBAJZ5EnCrzj92XdE3_Ms60I9o8YgWD-j8Hf2Gf1_fxwrFQ4UVlSQx0Wmc0elkNV1nTNV4k7STNC7e1iOCPUu74Ae7pNPrMqolhIRPvpqYFvo_Wcv31U7w-ldY-3Yz_x-L34ToYffvFn8byEa3Qu_FXm6wLZpyX5ciL8VmbAussdQlqmoQopIDF1KXulFDpfO-6YeNaXnOq7wuiqKoGi62utf9noteVU2528ualTlO0tittedp68NpsyZgW5Si3u02VvZo4xrWnKMbpVPrPWecM94xzlVKYCYOQ_CO0OlvB38v0hq6Zn7I0lxW1M0CzlPwhzZ1zPrlFFmZWxMpvnMgQxbbFzwFjNH4lBc_TTnocZRn4wPIgTDc_itS_H4XtZsl2HYkmtcMWRPtZGhc-q3yE-PH1Pb-lc3B_4WKGD-uc4iMH--jOLf8nwAAAP__vqsnTg">