diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index c829410..cbbaa1d 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -2793,6 +2793,7 @@
                                          const CXXMethodDecl *Old);
 
   bool CheckPureMethod(CXXMethodDecl *Method, SourceRange InitRange);
+
   //===--------------------------------------------------------------------===//
   // C++ Access Control
   //
@@ -3562,6 +3563,12 @@
   /// to implement it anywhere else.
   ActiveTemplateInstantiation LastTemplateInstantiationErrorContext;
 
+  /// \brief The stack of calls expression undergoing template instantiation.
+  ///
+  /// The top of this stack is used by a fixit instantiating unresolved
+  /// function calls to fix the AST to match the textual change it prints.
+  llvm::SmallVector<CallExpr *, 8> CallsUndergoingInstantiation;
+
   /// \brief A stack object to be created when performing template
   /// instantiation.
   ///