diff --git a/src/sat/smt/q_mbi.cpp b/src/sat/smt/q_mbi.cpp
index 3856b28a1..50662b49d 100644
--- a/src/sat/smt/q_mbi.cpp
+++ b/src/sat/smt/q_mbi.cpp
@@ -117,7 +117,7 @@ namespace q {
                 restrict_to_universe(vars.get(i), m_model->get_universe(s));            
         }
         var_subst subst(m);
-        expr_ref body = subst(body, vars);        
+        body = subst(body, vars);        
         if (is_forall(q)) 
             body = m.mk_not(body);        
         return body;
diff --git a/src/util/lim_vector.h b/src/util/lim_vector.h
index 24a4a3f0b..1249a9657 100644
--- a/src/util/lim_vector.h
+++ b/src/util/lim_vector.h
@@ -19,19 +19,19 @@ Author:
 #include "util/vector.h"
 
 template<typename T>
-class lim_svector : public svector<T> {
+class lim_svector : public svector<T, unsigned> {
     unsigned_vector  m_lim;
 public:
     lim_svector() {}
 
     void push_scope() {
-        m_lim.push_back(size());
+        m_lim.push_back(this->size());
     }
 
     void pop_scope(unsigned num_scopes) {
         SASSERT(num_scopes > 0);
         unsigned old_sz = m_lim.size() - num_scopes;
-        shrink(m_lim[old_sz]);
+        this->shrink(m_lim[old_sz]);
         m_lim.shrink(old_sz);
     }