diff --git a/src/interp/iz3base.h b/src/interp/iz3base.h
index 7c56b06a6..6bf09bb85 100755
--- a/src/interp/iz3base.h
+++ b/src/interp/iz3base.h
@@ -24,6 +24,16 @@ Revision History:
 #include "iz3mgr.h"
 #include "iz3scopes.h"
 
+namespace hash_space {
+  template <>
+    class hash<func_decl *> {
+  public:
+    size_t operator()(func_decl * const &s) const {
+      return (size_t) s;
+    }
+  };
+}
+
 /* Base class for interpolators. Includes an AST manager and a scoping
    object as bases. */
  
@@ -180,17 +190,6 @@ class iz3base : public iz3mgr, public scopes {
 
 };
 
-namespace hash_space {
-  template <>
-    class hash<iz3mgr::symb> {
-  public:
-    size_t operator()(const iz3mgr::symb &s) const {
-      return (size_t) s;
-    }
-  };
-}
-
-
 
 
 #endif