[PATCH] D47341: [Sema] Disable creating new delayed typos while correcting existing.

[Volodymyr Sapsai via Phabricator via cfe-commits]

vsapsai added a comment.

Some debugging details that can be useful but too specific for the commit message. When we have infinite loop, the steps are:

1. Detect typos `structVar1`, `structVar2`
2. Correct typos `structVar1`, `structVar2`
  1. Replace `structVar1` with `structVar`. Add corresponding object to `TransformTypos::TypoExprs`.
  2. Detect typo `fieldName1`. `NumTypos` becomes 0.
  3. Try to `CorrectDelayedTyposInExpr` for `fieldName1` TypoExpr. As there are no typos, no expression transformation.
  4. Replace `structVar2` with `structVar`. Add corresponding object to `TransformTypos::TypoExprs`.
  5. Detect typo `fieldName2`. `NumTypos` becomes 1.
    1. Replace `fieldName2` with `fieldName`
  6. Figure out that `structVar.fieldName.member2` is invalid, CheckAndAdvanceTypoExprCorrectionStreams
3. Try different TypoCorrection for `structVar1`. As it is empty, the correction fails.
4. CheckAndAdvanceTypoExprCorrectionStreams. Reset correction stream for `structVar1` and keep going with typo correction because `structVar2` typo correction stream isn't finished.
5. Try different TypoCorrection for `structVar1`.
  1. Replace `structVar1` with `structVar`
  2. Detect typo `fieldName1`
    1. Replace `fieldName1` with `fieldName`
  3. Figure out that `structVar.fieldName.member1` is invalid, CheckAndAdvanceTypoExprCorrectionStreams
6. Try different TypoCorrection for `structVar1`. As it is empty, the correction fails.
7. CheckAndAdvanceTypoExprCorrectionStreams over and over again.

After my fix the steps are:

1. Detect typos `structVar1`, `structVar2`
2. Correct typos `structVar1`, `structVar2`
  1. Replace `structVar1` with `structVar`. Add corresponding object to `TransformTypos::TypoExprs`.
  2. Detect typo `fieldName1`. `NumTypos` becomes 3.
    1. Replace `fieldName1` with `fieldName`
  3. Figure out that `structVar.fieldName.member1` is invalid, CheckAndAdvanceTypoExprCorrectionStreams
3. Try different TypoCorrection for `structVar1`. As it is empty, the correction fails.
4. All available typo corrections were tried because `TransformTypos::TypoExprs` contains only `structVar1`. Complete the typo correction.


https://reviews.llvm.org/D47341