diff --git a/llvm/docs/ProgrammersManual.rst b/llvm/docs/ProgrammersManual.rst
index 3779225..3214555 100644
--- a/llvm/docs/ProgrammersManual.rst
+++ b/llvm/docs/ProgrammersManual.rst
@@ -342,10 +342,13 @@
   public:
     MyError(std::string Msg) : Msg(Msg) {}
     void log(OStream &OS) const override { OS << "MyError - " << Msg; }
+    static char ID;
   private:
     std::string Msg;
   };
 
+  char MyError::ID = 0; // In MyError.cpp
+
   Error bar() {
     if (checkErrorCondition)
       return make_error<MyError>("Error condition detected");