diff --git a/clang/lib/AST/Interp/Function.cpp b/clang/lib/AST/Interp/Function.cpp
index e409002171c4b..0b7cfc4e28883 100644
--- a/clang/lib/AST/Interp/Function.cpp
+++ b/clang/lib/AST/Interp/Function.cpp
@@ -44,7 +44,7 @@ SourceInfo Function::getSource(CodePtr PC) const {
 }
 
 bool Function::isVirtual() const {
-  if (auto *M = dyn_cast<CXXMethodDecl>(F))
+  if (const auto *M = dyn_cast<CXXMethodDecl>(F))
     return M->isVirtual();
   return false;
 }