[clang] [Clang] fix cast failures by adjusting the resolution of record declaration contexts to handle semantic and lexical distinctions (PR #96228)

[Oleksandr T. via cfe-commits]

https://github.com/a-tarasyuk updated https://github.com/llvm/llvm-project/pull/96228

>From 9e2730da07df0ee5102912490a687ba40bf06def Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.tarasiuk at outlook.com>
Date: Mon, 24 Jun 2024 18:55:51 +0300
Subject: [PATCH] [Clang] fix cast failures by adjusting the resolution of
 record declaration contexts to handle semantic and lexical distinctions

---
 clang/docs/ReleaseNotes.rst                    |  1 +
 clang/lib/Sema/SemaDeclCXX.cpp                 |  5 ++++-
 .../class.compare/class.compare.default/p1.cpp | 18 ++++++++++++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index df579ae398c5e..86bd8cf4a6210 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -934,6 +934,7 @@ Bug Fixes to C++ Support
 - Fix an assertion failure caused by parsing a lambda used as a default argument for the value of a
   forward-declared class. (#GH93512).
 - Fixed a bug in access checking inside return-type-requirement of compound requirements. (#GH93788).
+- Fixed failed assertion when resolving context of defaulted comparison method outside of struct. (#GH96043).
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 9b220103247dd..0ecad756d4499 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -9192,7 +9192,10 @@ ComputeDefaultedComparisonExceptionSpec(Sema &S, SourceLocation Loc,
     EnterExpressionEvaluationContext Context(
         S, Sema::ExpressionEvaluationContext::Unevaluated);
 
-    CXXRecordDecl *RD = cast<CXXRecordDecl>(FD->getLexicalParent());
+    CXXRecordDecl *RD =
+        cast<CXXRecordDecl>(FD->getFriendObjectKind() == Decl::FOK_None
+                                ? FD->getDeclContext()
+                                : FD->getLexicalDeclContext());
     SourceLocation BodyLoc =
         FD->getEndLoc().isValid() ? FD->getEndLoc() : FD->getLocation();
     StmtResult Body =
diff --git a/clang/test/CXX/class/class.compare/class.compare.default/p1.cpp b/clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
index 252860bfc4de0..ddf82f432c2ea 100644
--- a/clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
+++ b/clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
@@ -265,3 +265,21 @@ void f2() {
                        // access info for unnamed bit-field
 }
 }
+
+namespace GH96043 {
+template <typename> class a {};
+template <typename b> b c(a<b>);
+template <typename d> class e {
+public:
+  typedef a<d *> f;
+  f begin();
+};
+template <typename d, typename g> constexpr bool operator==(d h, g i) {
+  return *c(h.begin()) == *c(i.begin());
+}
+struct j {
+  e<j> bar;
+  bool operator==(const j &) const;
+};
+bool j::operator==(const j &) const = default;
+}