diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
index 67f04b6a0cf9..57c3a1291a04 100644
--- a/clang/include/clang/AST/Expr.h
+++ b/clang/include/clang/AST/Expr.h
@@ -1519,6 +1519,9 @@ public:
     /// CK_NoOp - Used for const_cast.
     CK_NoOp,
 
+    /// CK_BaseToDerived - Base to derived class casts.
+    CK_BaseToDerived,
+
     /// CK_DerivedToBase - Derived to base class casts.
     CK_DerivedToBase,
 
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index a8ea752a4a7e..d43d58aee9ce 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -490,6 +490,8 @@ const char *CastExpr::getCastKindName() const {
     return "BitCast";
   case CastExpr::CK_NoOp:
     return "NoOp";
+  case CastExpr::CK_BaseToDerived:
+    return "BaseToDerived";
   case CastExpr::CK_DerivedToBase:
     return "DerivedToBase";
   case CastExpr::CK_Dynamic: