[clangd] Fix use-after-free with expected types in indexing

llvm-svn: 347563
diff --git a/clang-tools-extra/clangd/index/SymbolCollector.cpp b/clang-tools-extra/clangd/index/SymbolCollector.cpp
index 84aff8b..52a2069 100644
--- a/clang-tools-extra/clangd/index/SymbolCollector.cpp
+++ b/clang-tools-extra/clangd/index/SymbolCollector.cpp
@@ -587,9 +587,11 @@
   if (!Include.empty())
     S.IncludeHeaders.emplace_back(Include, 1);
 
+  llvm::Optional<OpaqueType> TypeStorage;
   if (S.Flags & Symbol::IndexedForCodeCompletion) {
-    if (auto T = OpaqueType::fromCompletionResult(*ASTCtx, SymbolCompletion))
-      S.Type = T->raw();
+    TypeStorage = OpaqueType::fromCompletionResult(*ASTCtx, SymbolCompletion);
+    if (TypeStorage)
+      S.Type = TypeStorage->raw();
   }
 
   S.Origin = Opts.Origin;