diff --git a/src/ast/ast.cpp b/src/ast/ast.cpp
index 6ea293b57..f3be7d2c6 100644
--- a/src/ast/ast.cpp
+++ b/src/ast/ast.cpp
@@ -319,26 +319,6 @@ func_decl::func_decl(symbol const & name, unsigned arity, sort * const * domain,
 //
 // -----------------------------------
 
-static app_flags mk_const_flags() {
-    app_flags r;
-    r.m_depth           = 1;
-    r.m_ground          = true;
-    r.m_has_quantifiers = false;
-    r.m_has_labels      = false;
-    return r;
-}
-
-static app_flags mk_default_app_flags() {
-    app_flags r;
-    r.m_depth           = 1;
-    r.m_ground          = true;
-    r.m_has_quantifiers = false;
-    r.m_has_labels      = false;
-    return r;
-}
-
-app_flags app::g_constant_flags = mk_const_flags();
-
 app::app(func_decl * decl, unsigned num_args, expr * const * args):
     expr(AST_APP),
     m_decl(decl),
@@ -1762,8 +1742,7 @@ ast * ast_manager::register_node_core(ast * n) {
         inc_ref(t->get_decl());
         unsigned num_args = t->get_num_args();
         if (num_args > 0) {
-            app_flags * f     = t->flags();
-            *f = mk_default_app_flags();
+            app_flags * f = &t->m_flags;
             SASSERT(t->is_ground());
             SASSERT(!t->has_quantifiers());
             SASSERT(!t->has_labels());
@@ -1776,13 +1755,13 @@ ast * ast_manager::register_node_core(ast * n) {
                 unsigned arg_depth = 0;
                 switch (arg->get_kind()) {
                 case AST_APP: {
-                    app_flags * arg_flags = to_app(arg)->flags();
-                    arg_depth = arg_flags->m_depth;
-                    if (arg_flags->m_has_quantifiers)
+                    app *app = to_app(arg);
+                    arg_depth = app->get_depth();
+                    if (app->has_quantifiers())
                         f->m_has_quantifiers = true;
-                    if (arg_flags->m_has_labels)
+                    if (app->has_labels())
                         f->m_has_labels = true;
-                    if (!arg_flags->m_ground)
+                    if (!app->is_ground())
                         f->m_ground = false;
                     break;
                 }
diff --git a/src/ast/ast.h b/src/ast/ast.h
index b4b3b1b2f..9618c7e12 100644
--- a/src/ast/ast.h
+++ b/src/ast/ast.h
@@ -704,6 +704,7 @@ struct app_flags {
     unsigned     m_ground:1;   // application does not have free variables or nested quantifiers.
     unsigned     m_has_quantifiers:1; // application has nested quantifiers.
     unsigned     m_has_labels:1; // application has nested labels.
+    app_flags() : m_depth(1), m_ground(1), m_has_quantifiers(0), m_has_labels(0) {}
 };
 
 class app : public expr {
@@ -711,19 +712,15 @@ class app : public expr {
 
     func_decl *  m_decl;
     unsigned     m_num_args;
+    app_flags    m_flags;
     expr *       m_args[0];
 
-    static app_flags g_constant_flags;
-
-    // remark: store term depth in the end of the app. the depth is only stored if the num_args > 0
     static unsigned get_obj_size(unsigned num_args) {
-        return num_args == 0 ? sizeof(app) : sizeof(app) + num_args * sizeof(expr *) + sizeof(app_flags);
+        return sizeof(app) + num_args * sizeof(expr *);
     }
 
     friend class tmp_app;
 
-    app_flags * flags() const { return m_num_args == 0 ? &g_constant_flags : reinterpret_cast<app_flags*>(const_cast<expr**>(m_args + m_num_args)); }
-
     app(func_decl * decl, unsigned num_args, expr * const * args);
 public:
     func_decl * get_decl() const { return m_decl; }
@@ -744,10 +741,10 @@ public:
     expr * const * end() const { return m_args + m_num_args; }
     sort * _get_sort() const { return get_decl()->get_range(); }
 
-    unsigned get_depth() const { return flags()->m_depth; }
-    bool is_ground() const { return flags()->m_ground; }
-    bool has_quantifiers() const { return flags()->m_has_quantifiers; }
-    bool has_labels() const { return flags()->m_has_labels; }
+    unsigned get_depth() const { return m_flags.m_depth; }
+    bool is_ground() const { return m_flags.m_ground; }
+    bool has_quantifiers() const { return m_flags.m_has_quantifiers; }
+    bool has_labels() const { return m_flags.m_has_labels; }
 };
 
 // -----------------------------------