Index: boost/phoenix/core/limits.hpp
===================================================================
--- boost/phoenix/core/limits.hpp	(working copy)
+++ boost/phoenix/core/limits.hpp	(working copy)
@@ -18,3 +18,7 @@
 #if defined(BOOST_PHOENIX_LIMIT)
-#define BOOST_PROTO_MAX_ARITY BOOST_PHOENIX_LIMIT
+# if !defined( BOOST_PROTO_MAX_ARITY )
+#  define BOOST_PROTO_MAX_ARITY BOOST_PHOENIX_LIMIT
+# elif (BOOST_PROTO_MAX_ARITY < BOOST_PHOENIX_LIMIT)
+#  error "BOOST_PROTO_MAX_ARITY is set too low"
+# endif
 #include <boost/proto/proto_fwd.hpp>
Index: libs/phoenix/test/Jamfile
===================================================================
--- libs/phoenix/test/Jamfile	(working copy)
+++ libs/phoenix/test/Jamfile	(working copy)
@@ -129,2 +129,3 @@
     [ run regression/bug7165.cpp ]
+    [ compile-fail regression/bug7166.cpp ]
     ;
Index: libs/phoenix/test/regression/bug7166.cpp
===================================================================
new file mode 100644
--- libs/phoenix/test/regression/bug7166.cpp	(revision 0)
+++ libs/phoenix/test/regression/bug7166.cpp	(working copy)
@@ -0,0 +1,7 @@
+#define BOOST_PROTO_MAX_ARITY 10
+#define BOOST_PHOENIX_LIMIT 20
+#include <boost/phoenix.hpp>
+ 
+int main()
+{
+}