diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c
index 64111f315e3..2de12b8bb49 100644
--- a/src/backend/parser/parse_agg.c
+++ b/src/backend/parser/parse_agg.c
@@ -579,13 +579,8 @@ check_agg_arguments(ParseState *pstate,
 	context.min_agglevel = -1;
 	context.sublevels_up = 0;
 
-	(void) expression_tree_walker((Node *) args,
-								  check_agg_arguments_walker,
-								  (void *) &context);
-
-	(void) expression_tree_walker((Node *) filter,
-								  check_agg_arguments_walker,
-								  (void *) &context);
+	(void) check_agg_arguments_walker((Node *) args, &context);
+	(void) check_agg_arguments_walker((Node *) filter, &context);
 
 	/*
 	 * If we found no vars nor aggs at all, it's a level-zero aggregate;
@@ -632,9 +627,7 @@ check_agg_arguments(ParseState *pstate,
 	{
 		context.min_varlevel = -1;
 		context.min_agglevel = -1;
-		(void) expression_tree_walker((Node *) directargs,
-									  check_agg_arguments_walker,
-									  (void *) &context);
+		(void) check_agg_arguments_walker((Node *) directargs, &context);
 		if (context.min_varlevel >= 0 && context.min_varlevel < agglevel)
 			ereport(ERROR,
 					(errcode(ERRCODE_GROUPING_ERROR),
diff --git a/src/test/regress/expected/aggregates.out b/src/test/regress/expected/aggregates.out
index 2611a80634c..0aa733008a1 100644
--- a/src/test/regress/expected/aggregates.out
+++ b/src/test/regress/expected/aggregates.out
@@ -1504,6 +1504,36 @@ select aggfns(distinct a,b,c order by a,c using ~<~,b) filter (where a > 1)
  {"(2,2,bar)","(3,1,baz)"}
 (1 row)
 
+-- check handling of bare boolean Var in FILTER
+select max(0) filter (where b1) from bool_test;
+ max 
+-----
+   0
+(1 row)
+
+select (select max(0) filter (where b1)) from bool_test;
+ max 
+-----
+   0
+(1 row)
+
+-- check for correct detection of nested-aggregate errors in FILTER
+select max(unique1) filter (where sum(ten) > 0) from tenk1;
+ERROR:  aggregate functions are not allowed in FILTER
+LINE 1: select max(unique1) filter (where sum(ten) > 0) from tenk1;
+                                          ^
+select (select max(unique1) filter (where sum(ten) > 0) from int8_tbl) from tenk1;
+ERROR:  aggregate function calls cannot be nested
+LINE 1: select (select max(unique1) filter (where sum(ten) > 0) from...
+                                                  ^
+select max(unique1) filter (where bool_or(ten > 0)) from tenk1;
+ERROR:  aggregate functions are not allowed in FILTER
+LINE 1: select max(unique1) filter (where bool_or(ten > 0)) from ten...
+                                          ^
+select (select max(unique1) filter (where bool_or(ten > 0)) from int8_tbl) from tenk1;
+ERROR:  aggregate function calls cannot be nested
+LINE 1: select (select max(unique1) filter (where bool_or(ten > 0)) ...
+                                                  ^
 -- ordered-set aggregates
 select p, percentile_cont(p) within group (order by x::float8)
 from generate_series(1,5) x,
diff --git a/src/test/regress/sql/aggregates.sql b/src/test/regress/sql/aggregates.sql
index adea65c10b0..6cb74b15b7e 100644
--- a/src/test/regress/sql/aggregates.sql
+++ b/src/test/regress/sql/aggregates.sql
@@ -568,6 +568,17 @@ select aggfns(distinct a,b,c order by a,c using ~<~,b) filter (where a > 1)
     from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
     generate_series(1,2) i;
 
+-- check handling of bare boolean Var in FILTER
+select max(0) filter (where b1) from bool_test;
+select (select max(0) filter (where b1)) from bool_test;
+
+-- check for correct detection of nested-aggregate errors in FILTER
+select max(unique1) filter (where sum(ten) > 0) from tenk1;
+select (select max(unique1) filter (where sum(ten) > 0) from int8_tbl) from tenk1;
+select max(unique1) filter (where bool_or(ten > 0)) from tenk1;
+select (select max(unique1) filter (where bool_or(ten > 0)) from int8_tbl) from tenk1;
+
+
 -- ordered-set aggregates
 
 select p, percentile_cont(p) within group (order by x::float8)