diff --git a/src/tgba/state.hh b/src/tgba/state.hh
index fea4dba84..f43e338ab 100644
--- a/src/tgba/state.hh
+++ b/src/tgba/state.hh
@@ -56,7 +56,7 @@ namespace spot
   struct state_ptr_less_than
   {
     bool
-    operator()(const state* left, const state *right) const
+    operator()(const state* left, const state* right) const
     {
       return left->compare(right) < 0;
     }