From e79fecbef1e55b3cda2e6e82d776a53d6494e144 Mon Sep 17 00:00:00 2001
From: Vlad Serebrennikov <brainvlad@gmail.com>
Date: Wed, 2 Jun 2021 23:17:43 +0300
Subject: [PATCH 1/3] Provide fresh DetachedCaptures for each nested fragment

like CXXFragmentParseRAII does with PendingUnquotes
---
 clang/include/clang/Sema/Sema.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 5d45f4e2ed7b..ecabfd298474 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -12497,16 +12497,20 @@ class Sema final {
   class CXXFragmentScopeRAII {
     Sema &S;
     bool PreviouslyInFragment;
+    SmallVector<CXXFragmentCaptureExpr *, 10> OriginalDetachedCaptures;
 
   public:
     CXXFragmentScopeRAII(Sema &S)
-        : S(S), PreviouslyInFragment(S.FragmentScope) {
+        : S(S), PreviouslyInFragment(S.FragmentScope),
+          OriginalDetachedCaptures() {
       S.FragmentScope = true;
+      OriginalDetachedCaptures.swap(S.DetachedCaptures);
     }
 
     ~CXXFragmentScopeRAII() {
       S.FragmentScope = PreviouslyInFragment;
       assert(S.DetachedCaptures.empty() && "captures left unattached");
+      OriginalDetachedCaptures.swap(S.DetachedCaptures);
     }
   };
 

From 2445bc8479642af79702c1b237c24fdca0e9b4fb Mon Sep 17 00:00:00 2001
From: Vlad Serebrennikov <brainvlad@gmail.com>
Date: Thu, 3 Jun 2021 00:38:31 +0300
Subject: [PATCH 2/3] Add a test

---
 .../meta/nested_fragment_with_captions.cpp    | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 clang/test/CXX/meta/nested_fragment_with_captions.cpp

diff --git a/clang/test/CXX/meta/nested_fragment_with_captions.cpp b/clang/test/CXX/meta/nested_fragment_with_captions.cpp
new file mode 100644
index 000000000000..ad5317c4d7be
--- /dev/null
+++ b/clang/test/CXX/meta/nested_fragment_with_captions.cpp
@@ -0,0 +1,42 @@
+// RUN: %clang_cc1 -freflection -std=c++2a %s
+
+#define assert(E) if (!(E)) __builtin_abort();
+
+namespace meta {
+  using info = decltype(^void);
+}
+
+struct Member {
+  const char* name;
+  meta::info type;
+};
+
+constexpr Member members[]{
+  Member{"a", ^int},
+  Member{"b", ^int}
+};
+
+consteval void generate_struct(const char* name) {
+  -> fragment namespace {
+    struct [# %{name} #] {
+      consteval {
+        for (auto member : %{members}) {
+          -> fragment struct {
+            typename [: %{member.type} :] [# %{member.name} #];
+          };
+        }
+      }
+    };
+  };
+}
+
+consteval {
+  generate_struct("S");
+}
+
+int main() {
+  S s{1, 2};
+  assert(s.a == 1);
+  assert(s.b == 2);
+  return 0;
+}
\ No newline at end of file

From 6d19d1b762507d18467c1c19251b512032a5a3be Mon Sep 17 00:00:00 2001
From: Vlad Serebrennikov <brainvlad@gmail.com>
Date: Thu, 3 Jun 2021 00:52:24 +0300
Subject: [PATCH 3/3] Rename test

---
 ...agment_with_captions.cpp => nested_fragment_with_captures.cpp} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename clang/test/CXX/meta/{nested_fragment_with_captions.cpp => nested_fragment_with_captures.cpp} (100%)

diff --git a/clang/test/CXX/meta/nested_fragment_with_captions.cpp b/clang/test/CXX/meta/nested_fragment_with_captures.cpp
similarity index 100%
rename from clang/test/CXX/meta/nested_fragment_with_captions.cpp
rename to clang/test/CXX/meta/nested_fragment_with_captures.cpp