[clang] [Clang] Fix a wrong diagnostic about a local variable inside a lambda in unevaluated context need capture (PR #165098)

[Erich Keane via cfe-commits]

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@@ -7061,8 +7061,17 @@ NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
     // anonymous unions in class templates).
   }
 
-  if (!ParentDependsOnArgs)
+  if (!ParentDependsOnArgs) {
+    if (CurrentInstantiationScope) {
+      if (llvm::PointerUnion<
+              Decl *, LocalInstantiationScope::DeclArgumentPack *> *Found =
+              CurrentInstantiationScope->getInstantiationOfIfExists(D)) {
+        if (Decl *FD = Found->dyn_cast<Decl *>())
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erichkeane wrote:

it seems to me that this is a problem not with getting the current instantiation, but with how we determine that 'ParentDependsOnArgs'.  I would imagine that the calculation there is incorrect for the lambdas, not trying to do a fixup here.

https://github.com/llvm/llvm-project/pull/165098