diff --git a/src/test/regress/expected/domain.out b/src/test/regress/expected/domain.out
index 5309234ce23d8ac262dc8a2eeddaa9932b03e582..c89be9535f17721efaff82c94192b5db749ef893 100644
--- a/src/test/regress/expected/domain.out
+++ b/src/test/regress/expected/domain.out
@@ -314,3 +314,17 @@ create domain str_domain2 as text check (value <> 'foo') default 'foo';
 -- should fail
 alter table domain_test add column d str_domain2;
 ERROR:  value for domain str_domain2 violates check constraint "str_domain2_check"
+-- Check that domain constraints on prepared statement parameters of
+-- unknown type are enforced correctly.
+create domain pos_int as int4 check (value > 0) not null;
+prepare s1 as select $1::pos_int = 10 as "is_ten";
+execute s1(10);
+ is_ten 
+--------
+ t
+(1 row)
+
+execute s1(0); -- should fail
+ERROR:  value for domain pos_int violates check constraint "pos_int_check"
+execute s1(NULL); -- should fail
+ERROR:  domain pos_int does not allow null values
diff --git a/src/test/regress/sql/domain.sql b/src/test/regress/sql/domain.sql
index c80b81262679125b49f37357c7a83bb99d232dd7..f6010e636cb8dcdd6a9fc3be92bca4c38e105a70 100644
--- a/src/test/regress/sql/domain.sql
+++ b/src/test/regress/sql/domain.sql
@@ -262,3 +262,12 @@ create domain str_domain2 as text check (value <> 'foo') default 'foo';
 
 -- should fail
 alter table domain_test add column d str_domain2;
+
+-- Check that domain constraints on prepared statement parameters of
+-- unknown type are enforced correctly.
+create domain pos_int as int4 check (value > 0) not null;
+prepare s1 as select $1::pos_int = 10 as "is_ten";
+
+execute s1(10);
+execute s1(0); -- should fail
+execute s1(NULL); -- should fail