[clang] [clang][bytecode] Create descriptor for invalid record fields (PR #187311)

[Timm Baeder via cfe-commits]

https://github.com/tbaederr created https://github.com/llvm/llvm-project/pull/187311

We otherwise refuse to register the Record for the RecordDecl entirely.

>From 14f50422303de98dd022502664b0944544fe413f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Wed, 18 Mar 2026 16:55:27 +0100
Subject: [PATCH] [clang][bytecode] Create descriptor for invalid record fields

---
 clang/lib/AST/ByteCode/Program.cpp |  2 +-
 clang/test/AST/ByteCode/lambda.cpp | 17 ++++++++++++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/clang/lib/AST/ByteCode/Program.cpp b/clang/lib/AST/ByteCode/Program.cpp
index efef5db177e56..ccef38ab14ebe 100644
--- a/clang/lib/AST/ByteCode/Program.cpp
+++ b/clang/lib/AST/ByteCode/Program.cpp
@@ -384,7 +384,7 @@ Record *Program::getOrCreateRecord(const RecordDecl *RD) {
           (Desc->isPrimitiveArray() && Desc->getPrimType() == PT_Ptr) ||
           (Desc->ElemRecord && Desc->ElemRecord->hasPtrField());
     } else {
-      return nullptr;
+      Desc = allocateDescriptor(FD);
     }
     Fields.emplace_back(FD, Desc, BaseSize);
     BaseSize += align(Desc->getAllocSize());
diff --git a/clang/test/AST/ByteCode/lambda.cpp b/clang/test/AST/ByteCode/lambda.cpp
index e4390483d0053..efc006dbfb1bc 100644
--- a/clang/test/AST/ByteCode/lambda.cpp
+++ b/clang/test/AST/ByteCode/lambda.cpp
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -fexperimental-new-constant-interpreter -verify=expected,both -std=c++20 %s
-// RUN: %clang_cc1 -verify=ref,both -std=c++20 %s
+// RUN: %clang_cc1                                         -verify=ref,both      -std=c++20 %s
 
 constexpr int a = 12;
 constexpr int f = [c = a]() { return c; }();
@@ -278,6 +278,21 @@ namespace InvalidCapture {
                      both-note {{read of non-const variable 'n' is not allowed in a constant expression}}
     } ();
   }
+
+  class Foo {
+    void a; // both-error {{field has incomplete type 'void'}}
+
+  public:
+    constexpr int bar() {
+      auto *p = &a;
+      *p;
+
+      auto b = [this]() {return 42;};
+      return b();
+    }
+  };
+  Foo FF;
+  static_assert(FF.bar() == 42, "");
 }
 
 constexpr int fn() {