diff --git a/bin/test.slime b/bin/test.slime
index 644d5de..d7aab74 100644
--- a/bin/test.slime
+++ b/bin/test.slime
@@ -1,17 +1,4 @@
-;; (when 1 (breakpoint))
-
-;; (if (eval 1)
-;;     (apply prog ((breakpoint)))
-;;   nil))
-
-;; (if (eval 1)
-;;     (eval (pair prog ((breakpoint)))))
-;;   nil))
-
-
 (defun ! (n)
-  (if (< n 2)
+  (ifs (< n 2)
       1
     (* n (! (- n 1)))))
-
-(erros "alskdj")
\ No newline at end of file
diff --git a/src/env.c b/src/env.c
index f1329d8..b30aecb 100644
--- a/src/env.c
+++ b/src/env.c
@@ -145,6 +145,7 @@ Ast_Node* lookup_symbol(Ast_Node* node, Environment* env) {
     }
 
     result = create_ast_node_built_in_function(sym->identifier);
+    result->sourceCodeLocation = node->sourceCodeLocation;
     if (result)
         return result;
 
diff --git a/src/eval.c b/src/eval.c
index 91c4519..5e9b30c 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -366,6 +366,10 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
         create_error(_type, node->sourceCodeLocation);  \
         return nullptr;                                 \
     }
+#define report_error_operator(_type) {                          \
+        create_error(_type, operator->sourceCodeLocation);  \
+        return nullptr;                                 \
+    }
 
     if (error)
         return nullptr;
@@ -416,7 +420,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
                     arguments_length = list_length(arguments);
                 }
                 if (arguments_length != 1) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
 
                 print(arguments->value.pair->first);
@@ -494,7 +498,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
                     arguments_length = list_length(arguments);
                 }
                 if (arguments_length == 0)
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
 
 
                 Function* function = new(Function);
@@ -632,7 +636,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
                     arguments_length = list_length(arguments);
                 }
                 if (arguments_length != 1) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
                 bool truthy;
                 try {
@@ -648,7 +652,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
                 }
 
                 if (arguments_length < 2) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
                 Ast_Node* condition_part = arguments->value.pair->first;
                 Ast_Node* condition;
@@ -674,7 +678,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
                     arguments_length = list_length(arguments);
                 }
                 if (arguments_length != 2 && arguments_length != 3) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
 
                 Ast_Node* condition = arguments->value.pair->first;
@@ -700,7 +704,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
             case Built_In_Quote: {
                 arguments_length = list_length(arguments);
                 if (arguments_length != 1) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
                 return arguments->value.pair->first;
             }
@@ -709,7 +713,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
                     arguments_length = list_length(arguments);
                 }
                 if (arguments_length != 2) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
 
                 Ast_Node* try_part   = arguments->value.pair->first;
@@ -731,7 +735,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
                     arguments_length = list_length(arguments);
                 }
                 if (arguments_length != 2) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
 
                 Ast_Node* symbol = arguments->value.pair->first;
@@ -804,7 +808,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
             }
             case Built_In_Mutate: {
                 if (arguments_length != 2)
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
 
                 if (evaluated_arguments->value.pair->first->type == Ast_Node_Type_Nil ||
                     evaluated_arguments->value.pair->first->type == Ast_Node_Type_Keyword)
@@ -820,7 +824,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
             }
             case Built_In_Copy: {
                 if (arguments_length != 1)
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
 
                 if (evaluated_arguments->value.pair->first->type == Ast_Node_Type_Nil ||
                     evaluated_arguments->value.pair->first->type == Ast_Node_Type_Keyword)
@@ -836,7 +840,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
             }
             case Built_In_Load: {
                 if (arguments_length != 1)
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
 
                 if (evaluated_arguments->value.pair->first->type != Ast_Node_Type_String)
                     report_error(Error_Type_Type_Missmatch);
@@ -850,13 +854,13 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
             }
             case Built_In_Pair: {
                 if (arguments_length != 2) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
                 return create_ast_node_pair(evaluated_arguments->value.pair->first, evaluated_arguments->value.pair->rest->value.pair->first);
             }
             case Built_In_First: {
                 if (arguments_length != 1) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
                 if (evaluated_arguments->value.pair->first->type == Ast_Node_Type_Nil)
                     return create_ast_node_nil();
@@ -867,7 +871,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
             }
             case Built_In_Rest: {
                 if (arguments_length != 1) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
                 if (evaluated_arguments->value.pair->first->type == Ast_Node_Type_Nil)
                     return create_ast_node_nil();
@@ -878,7 +882,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
             }
             case Built_In_Eval: {
                 if (arguments_length != 1) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
                 Ast_Node* result;
                 try {
@@ -905,13 +909,13 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
             }
             case Built_In_Error: {
                 if (arguments_length != 0) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
                 report_error(Error_Type_Unknown_Error);
             }
             case Built_In_Print: {
                 if (arguments_length != 1) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
                 print(evaluated_arguments->value.pair->first);
                 /* printf("\n"); */
@@ -919,7 +923,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
             }
             case Built_In_Read: {
                 if (arguments_length > 1) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
 
                 if (arguments_length == 1) {
@@ -934,7 +938,7 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
             }
             case Built_In_Type: {
                 if (arguments_length != 1) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
 
                 Ast_Node_Type type = evaluated_arguments->value.pair->first->type;
@@ -945,18 +949,18 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
                         return create_ast_node_keyword("dynamic-macro");
                     return create_ast_node_keyword("dynamic-function");
                 }
-                case Ast_Node_Type_Keyword:           return create_ast_node_keyword("keyword");
-                case Ast_Node_Type_Nil:               return create_ast_node_keyword("nil");
-                case Ast_Node_Type_T:                 return create_ast_node_keyword("t");
-                case Ast_Node_Type_Number:            return create_ast_node_keyword("number");
-                case Ast_Node_Type_Pair:              return create_ast_node_keyword("pair");
-                case Ast_Node_Type_String:            return create_ast_node_keyword("string");
-                case Ast_Node_Type_Symbol:            return create_ast_node_keyword("symbol");
+                case Ast_Node_Type_Keyword: return create_ast_node_keyword("keyword");
+                case Ast_Node_Type_Nil:     return create_ast_node_keyword("nil");
+                case Ast_Node_Type_T:       return create_ast_node_keyword("t");
+                case Ast_Node_Type_Number:  return create_ast_node_keyword("number");
+                case Ast_Node_Type_Pair:    return create_ast_node_keyword("pair");
+                case Ast_Node_Type_String:  return create_ast_node_keyword("string");
+                case Ast_Node_Type_Symbol:  return create_ast_node_keyword("symbol");
                 }
             }
             case Built_In_Exit: {
                 if (arguments_length > 1) {
-                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+                    report_error_operator(Error_Type_Wrong_Number_Of_Arguments);
                 }
 
                 if (arguments_length == 1) {