[clang] [RFC][C++20][Modules] Fix crash when function and lambda inside loaded from different modules (PR #104512)

[Chuanqi Xu via cfe-commits]

Valentin Clement =?utf-8?b?KOODkOODrOODsw=?=,Kyungwoo Lee <kyulee at meta.com>,Dmitry
 Polukhin <dmitry.polukhin at gmail.com>,Dmitry Polukhin
 <dmitry.polukhin at gmail.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/104512 at github.com>


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@@ -1155,6 +1155,16 @@ void ASTDeclReader::VisitFunctionDecl(FunctionDecl *FD) {
   for (unsigned I = 0; I != NumParams; ++I)
     Params.push_back(readDeclAs<ParmVarDecl>());
   FD->setParams(Reader.getContext(), Params);
+
+  // For the first decl add all lambdas inside for loading them later,
+  // otherwise skip them.
+  unsigned NumLambdas = Record.readInt();
+  if (FD->isFirstDecl()) {
+    for (unsigned I = 0; I != NumLambdas; ++I)
+      Reader.PendingLambdas.push_back(Record.readDeclID());
+  } else {
+    Record.skipInts(NumLambdas);
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ChuanqiXu9 wrote:

Here is not paired with writing process. It will only write a zero if it is not the first.

https://github.com/llvm/llvm-project/pull/104512