diff --git a/contrib/Makefile b/contrib/Makefile
index abd780f277..c68aa7be00 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -6,6 +6,7 @@ include $(top_builddir)/src/Makefile.global
 
 SUBDIRS = \
 		amcheck		\
+		pg_extension	\
 		auth_delay	\
 		auto_explain	\
 		basic_archive	\
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 4039ee0df7..2728e35105 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -7914,7 +7914,8 @@ get_name_for_var_field(Var *var, int fieldno,
 					{
 						char	   *dummy_name = palloc(32);
 
-						Assert(dpns->plan && IsA(dpns->plan, Result));
+						Assert(dpns->plan && (IsA(dpns->plan, Result) ||
+											  IsA(dpns->plan, CustomScan)));
 						snprintf(dummy_name, 32, "f%d", fieldno);
 						return dummy_name;
 					}
@@ -8045,7 +8046,8 @@ get_name_for_var_field(Var *var, int fieldno,
 					{
 						char	   *dummy_name = palloc(32);
 
-						Assert(dpns->plan && IsA(dpns->plan, Result));
+						Assert(dpns->plan && (IsA(dpns->plan, Result) ||
+											  IsA(dpns->plan, CustomScan)));
 						snprintf(dummy_name, 32, "f%d", fieldno);
 						return dummy_name;
 					}