diff --git a/clang/lib/Sema/SemaHLSL.cpp b/clang/lib/Sema/SemaHLSL.cpp
index 06130c985876f..0b1996b4789d6 100644
--- a/clang/lib/Sema/SemaHLSL.cpp
+++ b/clang/lib/Sema/SemaHLSL.cpp
@@ -1908,9 +1908,11 @@ void SemaHLSL::diagnoseSystemSemanticAttr(Decl *D, const ParsedAttr &AL,
 }
 
 void SemaHLSL::handleSemanticAttr(Decl *D, const ParsedAttr &AL) {
-  uint32_t IndexValue, ExplicitIndex;
-  SemaRef.checkUInt32Argument(AL, AL.getArgAsExpr(0), IndexValue);
-  SemaRef.checkUInt32Argument(AL, AL.getArgAsExpr(1), ExplicitIndex);
+  uint32_t IndexValue(0), ExplicitIndex(0);
+  if (!SemaRef.checkUInt32Argument(AL, AL.getArgAsExpr(0), IndexValue) ||
+      !SemaRef.checkUInt32Argument(AL, AL.getArgAsExpr(1), ExplicitIndex)) {
+    assert(0 && "HLSLUnparsedSemantic is expected to have 2 int arguments.");
+  }
   assert(IndexValue > 0 ? ExplicitIndex : true);
   std::optional<unsigned> Index =
       ExplicitIndex ? std::optional<unsigned>(IndexValue) : std::nullopt;