From f465d2cecaab97b3e765e0072596ea8e136254fb Mon Sep 17 00:00:00 2001
From: Jason Turner <jason@emptycrate.com>
Date: Thu, 20 Jul 2017 06:10:31 -0600
Subject: [PATCH] Make sure to not deref null parse node

---
 include/chaiscript/dispatchkit/proxy_functions.hpp | 11 ++++++++++-
 include/chaiscript/language/chaiscript_common.hpp  |  6 ++++--
 include/chaiscript/language/chaiscript_eval.hpp    |  4 +++-
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/include/chaiscript/dispatchkit/proxy_functions.hpp b/include/chaiscript/dispatchkit/proxy_functions.hpp
index 2afda8dd..0c60315f 100644
--- a/include/chaiscript/dispatchkit/proxy_functions.hpp
+++ b/include/chaiscript/dispatchkit/proxy_functions.hpp
@@ -354,6 +354,7 @@ namespace chaiscript
             m_param_types(std::move(t_param_types)),
             m_guard(std::move(t_guard)), m_parsenode(std::move(t_parsenode))
         {
+          // assert(t_parsenode);
         }
 
 
@@ -379,9 +380,17 @@ namespace chaiscript
           return m_guard;
         }
 
+        bool has_parse_tree() const {
+          return static_cast<bool>(m_parsenode);
+        }
+
         const AST_Node &get_parse_tree() const
         {
-          return *m_parsenode;
+          if (m_parsenode) {
+            return *m_parsenode;
+          } else {
+            throw std::runtime_error("Dynamic_Proxy_Function does not have parse_tree");
+          }
         }
 
 
diff --git a/include/chaiscript/language/chaiscript_common.hpp b/include/chaiscript/language/chaiscript_common.hpp
index 5fe377c4..b157cac2 100644
--- a/include/chaiscript/language/chaiscript_common.hpp
+++ b/include/chaiscript/language/chaiscript_common.hpp
@@ -262,6 +262,7 @@ namespace chaiscript
           bool t_dot_notation,
           const chaiscript::detail::Dispatch_Engine &t_ss)
       {
+        assert(t_func);
         int arity = t_func->get_arity();
         std::vector<Type_Info> types = t_func->get_param_types();
 
@@ -310,14 +311,14 @@ namespace chaiscript
         std::shared_ptr<const dispatch::Dynamic_Proxy_Function> dynfun 
           = std::dynamic_pointer_cast<const dispatch::Dynamic_Proxy_Function>(t_func);
 
-        if (dynfun)
+        if (dynfun && dynfun->has_parse_tree())
         {
           Proxy_Function f = dynfun->get_guard();
 
           if (f)
           {
             auto dynfunguard = std::dynamic_pointer_cast<const dispatch::Dynamic_Proxy_Function>(f);
-            if (dynfunguard)
+            if (dynfunguard && dynfunguard->has_parse_tree())
             {
               retval += " : " + format_guard(dynfunguard->get_parse_tree());
             }
@@ -350,6 +351,7 @@ namespace chaiscript
         std::stringstream ss;
         if (t_functions.size() == 1)
         {
+          assert(t_functions[0]);
           ss << "  Expected: " << format_types(t_functions[0], t_dot_notation, t_ss) << '\n';
         } else {
           ss << "  " << t_functions.size() << " overloads available:\n";
diff --git a/include/chaiscript/language/chaiscript_eval.hpp b/include/chaiscript/language/chaiscript_eval.hpp
index 3b9c7837..a9819440 100644
--- a/include/chaiscript/language/chaiscript_eval.hpp
+++ b/include/chaiscript/language/chaiscript_eval.hpp
@@ -288,7 +288,9 @@ namespace chaiscript
     template<typename T>
     struct Fun_Call_AST_Node : AST_Node_Impl<T> {
         Fun_Call_AST_Node(std::string t_ast_node_text, Parse_Location t_loc, std::vector<AST_Node_Impl_Ptr<T>> t_children) :
-          AST_Node_Impl<T>(std::move(t_ast_node_text), AST_Node_Type::Fun_Call, std::move(t_loc), std::move(t_children)) { }
+          AST_Node_Impl<T>(std::move(t_ast_node_text), AST_Node_Type::Fun_Call, std::move(t_loc), std::move(t_children)) { 
+            assert(!this->children.empty());
+          }
 
         template<bool Save_Params>
         Boxed_Value do_eval_internal(const chaiscript::detail::Dispatch_State &t_ss) const