[clang] [Clang] Only remove lambda scope after computing evaluation context (PR #154106)

[Erich Keane via cfe-commits]

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@@ -2134,6 +2135,11 @@ ConstructFixItRangeForUnusedCapture(Sema &S, SourceRange CaptureRange,
 
 ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
                                  LambdaScopeInfo *LSI) {
+  // Copy the LSI before PopFunctionScopeInfo removes it.
+  // FIXME: This is dumb. Store the lambda information somewhere that outlives
+  // the call operator.
+  LambdaScopeInfo LSICopy = *LSI;
+  LSI = &LSICopy;
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erichkeane wrote:

This seems awful strange.  I don't think this is  'the way', and since it changes the address of `LSI`, doesn't it cause any other links of it to break?  That doesn't seem right.

I DO find myself wondering whether we need to spend some effort just managing the `LambdaScopeInfo` in 1 place (push, do thing, pop) instead?  Also-also, other than making this variable, we aren't actually referencing LSICopy again?  What is going on?

https://github.com/llvm/llvm-project/pull/154106