[clang] [C++20][Modules] Fix crash when function and lambda inside loaded from different modules (PR #109167)

[Reid Kleckner via cfe-commits]

================
@@ -5706,6 +5707,27 @@ void ASTWriter::WriteDeclAndTypes(ASTContext &Context) {
     Stream.EmitRecord(DELAYED_NAMESPACE_LEXICAL_VISIBLE_RECORD,
                       DelayedNamespaceRecord);
 
+  if (!FunctionToLambdasMap.empty()) {
+    // TODO: on disk hash table for function to lambda mapping might be more
+    // efficent becuase it allows lazy deserialization.
+    RecordData FunctionToLambdasMapRecord;
+    for (const auto &Pair : FunctionToLambdasMap) {
----------------
rnk wrote:

Nevermind, I see you have a better fix.

https://github.com/llvm/llvm-project/pull/109167