diff --git a/src/assert.hpp b/src/assert.hpp
index ba08e2d..d98cda0 100644
--- a/src/assert.hpp
+++ b/src/assert.hpp
@@ -40,6 +40,7 @@
     } while(0)
 
 #define assert_list_length(_node, _len) assert("List length assertion", list_length(_node) == _len)
+#define assert_vector_length(_node, _len) assert("Vector length assertion", _node->value.vector.length == _len)
 
 #define assert(message, condition)                                              \
     do {                                                                        \
diff --git a/src/env.cpp b/src/env.cpp
index fcd821c..61d2704 100644
--- a/src/env.cpp
+++ b/src/env.cpp
@@ -75,6 +75,7 @@ namespace Slime {
 
     proc lookup_symbol(Lisp_Object* node, Environment* env) -> Lisp_Object* {
         profile_with_comment(node->value.symbol.data);
+        assert("env was null", env);
         // print(node);
         assert_type(node, Lisp_Object_Type::Symbol);
 
@@ -109,7 +110,7 @@ namespace Slime {
 
             for_hash_map (env->hm) {
                 written += print_indent();
-                written += print_to_file(file, "-> %{str} :: %{L_O} (%{ptr})\n",
+                written += print_to_file(file, "-> %{str} :: %{l_o} (%{ptr})\n",
                                          ((Lisp_Object*)key)->value.symbol.data, value, value);
             }
             for (u32 i = 0; i < env->parents.next_index; ++i) {
diff --git a/src/eval.cpp b/src/eval.cpp
index 7fe7edc..a994fb6 100644
--- a/src/eval.cpp
+++ b/src/eval.cpp
@@ -367,7 +367,7 @@ plot(sin(t))
                     Lisp_Object_Type type = pc->type;
                     switch (type) {
                         case Lisp_Object_Type::Symbol: {
-                            Current_Execution.cs.data[Current_Execution.cs.next_index-1]
+                            try Current_Execution.cs.data[Current_Execution.cs.next_index-1]
                                 = lookup_symbol(pc, get_current_environment());
                         } break;
                         case Lisp_Object_Type::Pair: {
diff --git a/src/forward_decls.cpp b/src/forward_decls.cpp
index 5c4a11a..522a2d9 100644
--- a/src/forward_decls.cpp
+++ b/src/forward_decls.cpp
@@ -59,6 +59,7 @@ namespace Slime {
         Lisp_Object* get_keyword(String identifier);
         Lisp_Object* get_keyword(const char*);
         Lisp_Object* create_lisp_object(f64);
+        Lisp_Object* create_lisp_object(void*);
         Lisp_Object* create_lisp_object(const char*);
         Lisp_Object* create_lisp_object_continuation();
         Lisp_Object* create_lisp_object_vector(Lisp_Object*);