diff --git a/src/parser.mly b/src/parser.mly
index 4722140..7cd039a 100644
--- a/src/parser.mly
+++ b/src/parser.mly
@@ -204,7 +204,13 @@ node_content:
                     (Format.asprintf "The node %s is already defined."
                                       node_name,
                     current_location()))
-        else Hashtbl.add defined_nodes node_name n; n };
+        else
+          if vars_distinct e_in e_out (snd $10)
+            then (Hashtbl.add defined_nodes node_name n; n)
+            else raise (MyParsingError
+                        ("There is a conflict between the names of local, input \
+                        or output variables.",
+                        current_location())) };
 
 node_body:
   | /* empty */ { ([], []) }
diff --git a/src/utils.ml b/src/utils.ml
index fa769a1..ae46399 100644
--- a/src/utils.ml
+++ b/src/utils.ml
@@ -22,6 +22,18 @@ let rec list_chk v = function
   | [] -> false
   | h :: t -> if h = v then true else list_chk v t
 
+let rec vars_distinct lv lv' lv'' =
+  match lv, lv', lv'' with
+  | [], [], _ -> true
+  | [], h :: t , l'' ->
+      if List.mem h l''
+        then false
+        else vars_distinct [] t l''
+  | h :: t, l', l'' ->
+      if List.mem h l' || List.mem h l''
+        then false
+        else vars_distinct t l' l''
+
 exception MyParsingError of (string * location)
 
 let type_const = function