Use type_eq instead of directly using ns.follow

Author: tautschnig

src/solvers/flattening/boolbv.cpp

@@ -23,6 +23,7 @@ Author: Daniel Kroening, kroening@kroening.com
 #include <util/string_constant.h>
 #include <util/symbol.h>
 #include <util/threeval.h>
+#include <util/type_eq.h>
 
 #include "boolbv_type.h"
 
@@ -569,10 +570,10 @@ bool boolbvt::boolbv_set_equality_to_true(const equal_exprt &expr)
   if(!equality_propagation)
     return true;
 
-  const typet &type=ns.follow(expr.lhs().type());
+  const typet &type=expr.lhs().type();
 
   if(expr.lhs().id()==ID_symbol &&
-     type==ns.follow(expr.rhs().type()) &&
+     type_eq(type, expr.rhs().type(), ns) &&
      type.id()!=ID_bool)
   {
     // see if it is an unbounded array