diff --git a/slither/detectors/variables/similar_variables.py b/slither/detectors/variables/similar_variables.py
index 465e1ce01d..9f8eaaa2d5 100644
--- a/slither/detectors/variables/similar_variables.py
+++ b/slither/detectors/variables/similar_variables.py
@@ -65,12 +65,16 @@ def detect_sim(contract: Contract) -> Set[Tuple[LocalVariable, LocalVariable]]:
 
         contract_var = contract.variables
 
-        all_var = set(all_var + contract_var)
+        all_var = list(set(all_var + contract_var))
 
         ret = []
-        for v1 in all_var:
-            for v2 in all_var:
-                if v1.name.lower() != v2.name.lower():
+        # pylint: disable=consider-using-enumerate
+        for i in range(len(all_var)):
+            v1 = all_var[i]
+            _v1_name_lower = v1.name.lower()
+            for j in range(i, len(all_var)):
+                v2 = all_var[j]
+                if _v1_name_lower != v2.name.lower():
                     if SimilarVarsDetection.similar(v1.name, v2.name):
                         if (v2, v1) not in ret:
                             ret.append((v1, v2))