diff --git a/src/ParsingDriver.cc b/src/ParsingDriver.cc
index af2cf849a6f8c68a4f9166be8ff3086c337827ec..86b066b3ea1070a9d548ef86fcecaf0184c8327b 100644
--- a/src/ParsingDriver.cc
+++ b/src/ParsingDriver.cc
@@ -2580,12 +2580,12 @@ ParsingDriver::add_var_expectation(const string &model_name)
 }
 
 expr_t
-ParsingDriver::add_pac_expectation(const string &var_model_name)
+ParsingDriver::add_pac_expectation(const string &model_name)
 {
   if (data_tree == occbin_constraints_tree.get())
-    error("The 'var_expectation' operator is forbidden in 'occbin_constraints'.");
+    error("The 'pac_expectation' operator is forbidden in 'occbin_constraints'.");
 
-  return data_tree->AddPacExpectation(var_model_name);
+  return data_tree->AddPacExpectation(model_name);
 }
 
 void
diff --git a/src/ParsingDriver.hh b/src/ParsingDriver.hh
index af0dca750d46226a54c8ce68da096b912b5ee0b3..0c21db3b6aa58a68a0333569358aada9d73e1968 100644
--- a/src/ParsingDriver.hh
+++ b/src/ParsingDriver.hh
@@ -738,7 +738,7 @@ public:
   //! Writes token "VAR_EXPECTATION(model_name)" to model tree
   expr_t add_var_expectation(const string &model_name);
   //! Writes token "PAC_EXPECTATION(model_name, discount, growth)" to model tree
-  expr_t add_pac_expectation(const string &var_model_name);
+  expr_t add_pac_expectation(const string &model_name);
   //! Creates pac_model statement
   void begin_pac_growth();
   void begin_pac_model();