diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ee47547..b761fdf 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -2147,15 +2147,17 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
 			if (i < index_form->indnkeyatts)
 			{
 				/*
-				 * Insist on default opclass and sort options.  While the
-				 * index would still work as a constraint with non-default
-				 * settings, it might not provide exactly the same uniqueness
-				 * semantics as you'd get from a normally-created constraint;
-				 * and there's also the dump/reload problem mentioned above.
+				 * Insist on default opclass, collation, and sort options.
+				 * While the index would still work as a constraint with
+				 * non-default settings, it might not provide exactly the same
+				 * uniqueness semantics as you'd get from a normally-created
+				 * constraint; and there's also the dump/reload problem
+				 * mentioned above.
 				 */
 				defopclass = GetDefaultOpClass(attform->atttypid,
 											   index_rel->rd_rel->relam);
 				if (indclass->values[i] != defopclass ||
+					attform->attcollation != index_rel->rd_indcollation[i] ||
 					index_rel->rd_indoption[i] != 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_WRONG_OBJECT_TYPE),
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index 1cdb7a9..645ae2c 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -1479,6 +1479,19 @@ primary key, btree, for table "public.cwi_test"
 DROP INDEX cwi_replaced_pkey;	-- Should fail; a constraint depends on it
 ERROR:  cannot drop index cwi_replaced_pkey because constraint cwi_replaced_pkey on table cwi_test requires it
 HINT:  You can drop constraint cwi_replaced_pkey on table cwi_test instead.
+-- Check that non-default index options are rejected
+CREATE UNIQUE INDEX cwi_uniq3_idx ON cwi_test(a desc);
+ALTER TABLE cwi_test ADD UNIQUE USING INDEX cwi_uniq3_idx;  -- fail
+ERROR:  index "cwi_uniq3_idx" column number 1 does not have default sorting behavior
+LINE 1: ALTER TABLE cwi_test ADD UNIQUE USING INDEX cwi_uniq3_idx;
+                                 ^
+DETAIL:  Cannot create a primary key or unique constraint using such an index.
+CREATE UNIQUE INDEX cwi_uniq4_idx ON cwi_test(b collate "POSIX");
+ALTER TABLE cwi_test ADD UNIQUE USING INDEX cwi_uniq4_idx;  -- fail
+ERROR:  index "cwi_uniq4_idx" column number 1 does not have default sorting behavior
+LINE 1: ALTER TABLE cwi_test ADD UNIQUE USING INDEX cwi_uniq4_idx;
+                                 ^
+DETAIL:  Cannot create a primary key or unique constraint using such an index.
 DROP TABLE cwi_test;
 -- ADD CONSTRAINT USING INDEX is forbidden on partitioned tables
 CREATE TABLE cwi_test(a int) PARTITION BY hash (a);
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index 7659808..73a55ea 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -538,6 +538,12 @@ ALTER TABLE cwi_test DROP CONSTRAINT cwi_uniq_idx,
 
 DROP INDEX cwi_replaced_pkey;	-- Should fail; a constraint depends on it
 
+-- Check that non-default index options are rejected
+CREATE UNIQUE INDEX cwi_uniq3_idx ON cwi_test(a desc);
+ALTER TABLE cwi_test ADD UNIQUE USING INDEX cwi_uniq3_idx;  -- fail
+CREATE UNIQUE INDEX cwi_uniq4_idx ON cwi_test(b collate "POSIX");
+ALTER TABLE cwi_test ADD UNIQUE USING INDEX cwi_uniq4_idx;  -- fail
+
 DROP TABLE cwi_test;
 
 -- ADD CONSTRAINT USING INDEX is forbidden on partitioned tables