[clang] [Clang] Added check for unexpanded pack in attribute [[assume]] (PR #91893)

[Azmat Yusuf via cfe-commits]

https://github.com/azmat-y created https://github.com/llvm/llvm-project/pull/91893

Added a check for unexpanded parameter pack in attribute [[assume]]. Tested it with expected-error statements from clang fronted. This fixes #91232. @Sirraide 

>From cbb35bd010f2d46ae70367549a2838841a55aeb7 Mon Sep 17 00:00:00 2001
From: Azmat Yusuf <azmatyusuf2022 at gmail.com>
Date: Sun, 12 May 2024 20:49:14 +0530
Subject: [PATCH] [Clang] Added check for unexpanded pack in attribute
 [[assume]]

---
 clang/lib/Sema/SemaStmtAttr.cpp     | 5 +++++
 clang/test/SemaCXX/cxx23-assume.cpp | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
index 1c84830b6ddd2..36f8ecadcfab7 100644
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -670,6 +670,11 @@ ExprResult Sema::ActOnCXXAssumeAttr(Stmt *St, const ParsedAttr &A,
   }
 
   auto *Assumption = A.getArgAsExpr(0);
+
+  if (DiagnoseUnexpandedParameterPack(Assumption)) {
+    return ExprError();
+  }
+
   if (Assumption->getDependence() == ExprDependence::None) {
     ExprResult Res = BuildCXXAssumeExpr(Assumption, A.getAttrName(), Range);
     if (Res.isInvalid())
diff --git a/clang/test/SemaCXX/cxx23-assume.cpp b/clang/test/SemaCXX/cxx23-assume.cpp
index 8676970de14f6..e67d72ae0a995 100644
--- a/clang/test/SemaCXX/cxx23-assume.cpp
+++ b/clang/test/SemaCXX/cxx23-assume.cpp
@@ -138,3 +138,8 @@ constexpr int foo() {
 }
 
 static_assert(foo() == 0);
+
+template <bool ...val>
+void f() {
+    [[assume(val)]]; // expected-error {{expression contains unexpanded parameter pack}}
+}