diff --git a/CHANGELOG.md b/CHANGELOG.md
index 69eb70d..03ac821 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.2.1 (unreleased)
+
+- Fixed `operator is not unique` error
+
 ## 0.2.0 (2021-10-03)
 
 - Added support for Postgres 14
diff --git a/sql/vector--0.2.0--0.2.1.sql b/sql/vector--0.2.0--0.2.1.sql
new file mode 100644
index 0000000..55e76de
--- /dev/null
+++ b/sql/vector--0.2.0--0.2.1.sql
@@ -0,0 +1,19 @@
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "ALTER EXTENSION vector UPDATE TO '0.2.1'" to load this file. \quit
+
+DROP CAST (integer[] AS vector);
+DROP CAST (real[] AS vector);
+DROP CAST (double precision[] AS vector);
+DROP CAST (numeric[] AS vector);
+
+CREATE CAST (integer[] AS vector)
+  WITH FUNCTION array_to_vector(integer[], integer, boolean) AS ASSIGNMENT;
+
+CREATE CAST (real[] AS vector)
+  WITH FUNCTION array_to_vector(real[], integer, boolean) AS ASSIGNMENT;
+
+CREATE CAST (double precision[] AS vector)
+  WITH FUNCTION array_to_vector(double precision[], integer, boolean) AS ASSIGNMENT;
+
+CREATE CAST (numeric[] AS vector)
+  WITH FUNCTION array_to_vector(numeric[], integer, boolean) AS ASSIGNMENT;
diff --git a/sql/vector.sql b/sql/vector.sql
index 452154f..6f89c1f 100644
--- a/sql/vector.sql
+++ b/sql/vector.sql
@@ -109,16 +109,16 @@ CREATE CAST (vector AS vector)
 	WITH FUNCTION vector(vector, integer, boolean) AS IMPLICIT;
 
 CREATE CAST (integer[] AS vector)
-	WITH FUNCTION array_to_vector(integer[], integer, boolean) AS IMPLICIT;
+	WITH FUNCTION array_to_vector(integer[], integer, boolean) AS ASSIGNMENT;
 
 CREATE CAST (real[] AS vector)
-	WITH FUNCTION array_to_vector(real[], integer, boolean) AS IMPLICIT;
+	WITH FUNCTION array_to_vector(real[], integer, boolean) AS ASSIGNMENT;
 
 CREATE CAST (double precision[] AS vector)
-	WITH FUNCTION array_to_vector(double precision[], integer, boolean) AS IMPLICIT;
+	WITH FUNCTION array_to_vector(double precision[], integer, boolean) AS ASSIGNMENT;
 
 CREATE CAST (numeric[] AS vector)
-	WITH FUNCTION array_to_vector(numeric[], integer, boolean) AS IMPLICIT;
+	WITH FUNCTION array_to_vector(numeric[], integer, boolean) AS ASSIGNMENT;
 
 CREATE CAST (vector AS real[])
 	WITH FUNCTION vector_to_float4(vector, integer, boolean) AS IMPLICIT;
diff --git a/test/expected/functions.out b/test/expected/functions.out
index 930a60e..8a2efb7 100644
--- a/test/expected/functions.out
+++ b/test/expected/functions.out
@@ -54,3 +54,9 @@ SELECT cosine_distance('[1,2]', '[0,0]');
 
 SELECT cosine_distance('[1,2]', '[3]');
 ERROR:  different vector dimensions 2 and 1
+SELECT ARRAY[1,2,3] = ARRAY[1,2,3];
+ ?column? 
+----------
+ t
+(1 row)
+
diff --git a/test/sql/functions.sql b/test/sql/functions.sql
index 7f397a2..adb7695 100644
--- a/test/sql/functions.sql
+++ b/test/sql/functions.sql
@@ -16,3 +16,5 @@ SELECT inner_product('[1,2]', '[3]');
 SELECT round(cosine_distance('[1,2]', '[2,4]')::numeric, 5);
 SELECT cosine_distance('[1,2]', '[0,0]');
 SELECT cosine_distance('[1,2]', '[3]');
+
+SELECT ARRAY[1,2,3] = ARRAY[1,2,3];