Remove ns.follow when types cannot be hidden behind tags

Neither arrays nor Booleans use tag types.

Author: tautschnig

src/util/expr_initializer.cpp

@@ -263,7 +263,7 @@ exprt expr_initializert<nondet>::expr_initializer_rec(
   {
     exprt result = expr_initializer_rec(ns.follow(type), source_location);
     // we might have mangled the type for arrays, so keep that
-    if(ns.follow(type).id()!=ID_array)
+    if(type.id() != ID_array)
       result.type()=type;
 
     return result;

src/util/expr_util.cpp

@@ -104,10 +104,9 @@ exprt is_not_zero(
   // Note that this returns a proper bool_typet(), not a C/C++ boolean.
   // To get a C/C++ boolean, add a further typecast.
 
-  const typet &src_type=
-    src.type().id()==ID_c_enum_tag?
-    ns.follow_tag(to_c_enum_tag_type(src.type())):
-    ns.follow(src.type());
+  const typet &src_type = src.type().id() == ID_c_enum_tag
+                            ? ns.follow_tag(to_c_enum_tag_type(src.type()))
+                            : src.type();
 
   if(src_type.id()==ID_bool) // already there
     return src; // do nothing