fix warnings

Author: facontidavide

include/behaviortree_cpp/scripting/operators.hpp

@@ -162,6 +162,7 @@ struct ExprBinaryArithmetic : ExprBase
       case logic_or:
         return "||";
     }
+    return "";
   }
 
   expr_ptr lhs, rhs;
@@ -307,6 +308,7 @@ struct ExprComparison : ExprBase
       case greater_equal:
         return ">=";
     }
+    return "";
   }
 
   std::vector<op_t> ops;
@@ -445,6 +447,7 @@ struct ExprAssignment : ExprBase
       case assign_div:
         return "/=";
     }
+    return "";
   }
 
   expr_ptr lhs, rhs;

tests/script_parser_test.cpp

@@ -25,7 +25,7 @@ BT::Any GetScriptResult(BT::Ast::Environment& environment, const char* text)
   {
     return {};
   }
-};
+}
 
 TEST(ParserTest, AnyTypes)
 {