[clang] [Clang][Sema] Fix a crash in lambda instantiation (PR #85565)

[via cfe-commits]

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@@ -394,6 +394,7 @@ Bug Fixes to C++ Support
   expression references to an entity declared outside of the lambda. (#GH64808)
 - Clang's __builtin_bit_cast will now produce a constant value for records with empty bases. See:
   (#GH82383)
+- Fix a crash in lambda instantiation that missing set ``ThisType`` when checking capture. Fixes (#GH85343).
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Sirraide wrote:

```suggestion
- Fix a crash when instantiating a lambda that captures ``this`` outside of its context. Fixes (#GH85343).
```

https://github.com/llvm/llvm-project/pull/85565