From 2719a5d7ef30908de9e140ab4fd1b01c9e11d51c Mon Sep 17 00:00:00 2001
From: Tilak Chad <tilakchad111@gmail.com>
Date: Tue, 31 Dec 2024 21:57:50 +0545
Subject: [PATCH] [Clang] Resolved type of expression indexing into pack of
 values of a non-dependent type

---
 clang/docs/ReleaseNotes.rst                |  1 +
 clang/lib/AST/ExprCXX.cpp                  |  2 +-
 clang/test/SemaCXX/cxx2c-pack-indexing.cpp | 16 ++++++++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 983c1da20ed4c..612541b0ddf84 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -886,6 +886,7 @@ Bug Fixes to C++ Support
   out of a module (which is the case e.g. in MSVC's implementation of ``std`` module). (#GH118218)
 - Fixed a pack expansion issue in checking unexpanded parameter sizes. (#GH17042)
 - Fixed a bug where captured structured bindings were modifiable inside non-mutable lambda (#GH95081)
+- Fixed an issue while resolving type of expression indexing into a pack of values of non-dependent type (#GH121242)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/AST/ExprCXX.cpp b/clang/lib/AST/ExprCXX.cpp
index fc09d24fc30cb..5bf5d6adf525a 100644
--- a/clang/lib/AST/ExprCXX.cpp
+++ b/clang/lib/AST/ExprCXX.cpp
@@ -1722,7 +1722,7 @@ PackIndexingExpr *PackIndexingExpr::Create(
   if (Index && FullySubstituted && !SubstitutedExprs.empty())
     Type = SubstitutedExprs[*Index]->getType();
   else
-    Type = Context.DependentTy;
+    Type = PackIdExpr->getType();
 
   void *Storage =
       Context.Allocate(totalSizeToAlloc<Expr *>(SubstitutedExprs.size()));
diff --git a/clang/test/SemaCXX/cxx2c-pack-indexing.cpp b/clang/test/SemaCXX/cxx2c-pack-indexing.cpp
index cb679a6c3ad87..58b642d2735b6 100644
--- a/clang/test/SemaCXX/cxx2c-pack-indexing.cpp
+++ b/clang/test/SemaCXX/cxx2c-pack-indexing.cpp
@@ -305,3 +305,19 @@ template <class... Args> struct mdispatch_ {
 mdispatch_<int, int> d;
 
 } // namespace GH116105
+
+namespace GH121242 {
+    // Non-dependent type pack access
+    template <int...x>
+    int y = x...[0];
+
+    struct X {};
+
+    template <X...x>
+    X z = x...[0];
+
+    void foo() {
+        (void)y<0>;
+        (void)z<X{}>;
+    }
+} // namespace GH121242