diff --git a/vhdlpp/scope.cc b/vhdlpp/scope.cc
index 2ce681697..a617e0778 100644
--- a/vhdlpp/scope.cc
+++ b/vhdlpp/scope.cc
@@ -104,7 +104,7 @@ const VType*ScopeBase::find_type(perm_string by_name)
 	    return cur->second;
 }
 
-bool ScopeBase::find_constant(perm_string by_name, const VType*&typ, Expression*&exp)
+bool ScopeBase::find_constant(perm_string by_name, const VType*&typ, Expression*&exp) const
 {
       map<perm_string,struct const_t*>::const_iterator cur = cur_constants_.find(by_name);
       if (cur == cur_constants_.end()) {
@@ -281,6 +281,11 @@ bool ActiveScope::is_vector_name(perm_string name) const
       if (find_variable(name))
 	    return true;
 
+      const VType*dummy_type;
+      Expression*dummy_exp;
+      if (find_constant(name, dummy_type, dummy_exp))
+	    return true;
+
       if (context_entity_ && context_entity_->find_port(name))
 	    return true;
 
diff --git a/vhdlpp/scope.h b/vhdlpp/scope.h
index ea4c55d64..5f1d4c33a 100644
--- a/vhdlpp/scope.h
+++ b/vhdlpp/scope.h
@@ -53,7 +53,7 @@ class ScopeBase {
       virtual ~ScopeBase() =0;
 
       const VType* find_type(perm_string by_name);
-      bool find_constant(perm_string by_name, const VType*&typ, Expression*&exp);
+      bool find_constant(perm_string by_name, const VType*&typ, Expression*&exp) const;
       Signal* find_signal(perm_string by_name) const;
       Variable* find_variable(perm_string by_name) const;
       virtual const InterfacePort* find_param(perm_string by_name) const;