[clang] [Sema] LambdaScopeForCallOperatorInstantiationRAII - fix typo in early out logic (PR #96888)

[Younan Zhang via cfe-commits]

zyn0217 wrote:

Looks like we have hit the assert in `SemaTemplate/alias-template-with-lambdas.cpp`. I brought that dirty test, and I'll take a look this weekend.

https://github.com/llvm/llvm-project/pull/96888