diff --git a/src/test/regress/expected/.gitignore b/src/test/regress/expected/.gitignore
index 93c56c85a0..b99caf5f40 100644
--- a/src/test/regress/expected/.gitignore
+++ b/src/test/regress/expected/.gitignore
@@ -1,5 +1,6 @@
 /constraints.out
 /copy.out
+/create_function_0.out
 /create_function_1.out
 /create_function_2.out
 /largeobject.out
diff --git a/src/test/regress/expected/conversion.out b/src/test/regress/expected/conversion.out
index e34ab20974..04fdcba496 100644
--- a/src/test/regress/expected/conversion.out
+++ b/src/test/regress/expected/conversion.out
@@ -41,7 +41,7 @@ DROP USER regress_conversion_user;
 -- Test built-in conversion functions.
 --
 -- Helper function to test a conversion. Uses the test_enc_conversion function
--- that was created in the create_function_1 test.
+-- that was created in the create_function_0 test.
 create or replace function test_conv(
   input IN bytea,
   src_encoding IN text,
diff --git a/src/test/regress/expected/opr_sanity.out b/src/test/regress/expected/opr_sanity.out
index 7a0d345b60..562b586d8e 100644
--- a/src/test/regress/expected/opr_sanity.out
+++ b/src/test/regress/expected/opr_sanity.out
@@ -16,61 +16,6 @@
 --
 -- NB: run this test earlier than the create_operator test, because
 -- that test creates some bogus operators...
--- Helper functions to deal with cases where binary-coercible matches are
--- allowed.
--- This should match IsBinaryCoercible() in parse_coerce.c.
--- It doesn't currently know about some cases, notably domains, anyelement,
--- anynonarray, anyenum, or record, but it doesn't need to (yet).
-create function binary_coercible(oid, oid) returns bool as $$
-begin
-  if $1 = $2 then return true; end if;
-  if EXISTS(select 1 from pg_catalog.pg_cast where
-            castsource = $1 and casttarget = $2 and
-            castmethod = 'b' and castcontext = 'i')
-  then return true; end if;
-  if $2 = 'pg_catalog.any'::pg_catalog.regtype then return true; end if;
-  if $2 = 'pg_catalog.anyarray'::pg_catalog.regtype then
-    if EXISTS(select 1 from pg_catalog.pg_type where
-              oid = $1 and typelem != 0 and
-              typsubscript = 'pg_catalog.array_subscript_handler'::pg_catalog.regproc)
-    then return true; end if;
-  end if;
-  if $2 = 'pg_catalog.anyrange'::pg_catalog.regtype then
-    if (select typtype from pg_catalog.pg_type where oid = $1) = 'r'
-    then return true; end if;
-  end if;
-  if $2 = 'pg_catalog.anymultirange'::pg_catalog.regtype then
-    if (select typtype from pg_catalog.pg_type where oid = $1) = 'm'
-    then return true; end if;
-  end if;
-  return false;
-end
-$$ language plpgsql strict stable;
--- This one ignores castcontext, so it will allow cases where an explicit
--- (but still binary) cast would be required to convert the input type.
--- We don't currently use this for any tests in this file, but it is a
--- reasonable alternative definition for some scenarios.
-create function explicitly_binary_coercible(oid, oid) returns bool as $$
-begin
-  if $1 = $2 then return true; end if;
-  if EXISTS(select 1 from pg_catalog.pg_cast where
-            castsource = $1 and casttarget = $2 and
-            castmethod = 'b')
-  then return true; end if;
-  if $2 = 'pg_catalog.any'::pg_catalog.regtype then return true; end if;
-  if $2 = 'pg_catalog.anyarray'::pg_catalog.regtype then
-    if EXISTS(select 1 from pg_catalog.pg_type where
-              oid = $1 and typelem != 0 and
-              typsubscript = 'pg_catalog.array_subscript_handler'::pg_catalog.regproc)
-    then return true; end if;
-  end if;
-  if $2 = 'pg_catalog.anyrange'::pg_catalog.regtype then
-    if (select typtype from pg_catalog.pg_type where oid = $1) = 'r'
-    then return true; end if;
-  end if;
-  return false;
-end
-$$ language plpgsql strict stable;
 -- **************** pg_proc ****************
 -- Look for illegal values in pg_proc fields.
 SELECT p1.oid, p1.proname
diff --git a/src/test/regress/expected/type_sanity.out b/src/test/regress/expected/type_sanity.out
index 5480f979c6..f567fd378e 100644
--- a/src/test/regress/expected/type_sanity.out
+++ b/src/test/regress/expected/type_sanity.out
@@ -635,7 +635,7 @@ WHERE (rngcollation = 0) != (typcollation = 0);
 (0 rows)
 
 -- opclass had better be a btree opclass accepting the subtype.
--- We must allow anyarray matches, cf opr_sanity's binary_coercible()
+-- We must allow anyarray matches, cf IsBinaryCoercible()
 SELECT p1.rngtypid, p1.rngsubtype, o.opcmethod, o.opcname
 FROM pg_range p1 JOIN pg_opclass o ON o.oid = p1.rngsubopc
 WHERE o.opcmethod != 403 OR
diff --git a/src/test/regress/input/create_function_0.source b/src/test/regress/input/create_function_0.source
new file mode 100644
index 0000000000..28fe373c7d
--- /dev/null
+++ b/src/test/regress/input/create_function_0.source
@@ -0,0 +1,42 @@
+--
+-- CREATE_FUNCTION_0
+--
+-- This makes available various test support functions that are in
+-- src/test/regress/regress.c
+-- (although a few more are created in create_function_1)
+--
+
+CREATE FUNCTION make_tuple_indirect (record)
+    RETURNS record
+    AS '@libdir@/regress@DLSUFFIX@'
+    LANGUAGE C STRICT;
+
+CREATE FUNCTION test_atomic_ops()
+    RETURNS bool
+    AS '@libdir@/regress@DLSUFFIX@'
+    LANGUAGE C;
+
+CREATE FUNCTION test_fdw_handler()
+    RETURNS fdw_handler
+    AS '@libdir@/regress@DLSUFFIX@', 'test_fdw_handler'
+    LANGUAGE C;
+
+CREATE FUNCTION test_support_func(internal)
+    RETURNS internal
+    AS '@libdir@/regress@DLSUFFIX@', 'test_support_func'
+    LANGUAGE C STRICT;
+
+CREATE FUNCTION test_opclass_options_func(internal)
+    RETURNS void
+    AS '@libdir@/regress@DLSUFFIX@', 'test_opclass_options_func'
+    LANGUAGE C;
+
+CREATE FUNCTION test_enc_conversion(bytea, name, name, bool,
+                                    validlen OUT int, result OUT bytea)
+    AS '@libdir@/regress@DLSUFFIX@', 'test_enc_conversion'
+    LANGUAGE C STRICT;
+
+CREATE FUNCTION binary_coercible(oid, oid)
+    RETURNS bool
+    AS '@libdir@/regress@DLSUFFIX@', 'binary_coercible'
+    LANGUAGE C STRICT STABLE PARALLEL SAFE;
diff --git a/src/test/regress/input/create_function_1.source b/src/test/regress/input/create_function_1.source
index 6c69b7fe6c..8b58860245 100644
--- a/src/test/regress/input/create_function_1.source
+++ b/src/test/regress/input/create_function_1.source
@@ -52,36 +52,6 @@ CREATE FUNCTION set_ttdummy (int4)
         AS '@libdir@/regress@DLSUFFIX@'
         LANGUAGE C STRICT;
 
-CREATE FUNCTION make_tuple_indirect (record)
-        RETURNS record
-        AS '@libdir@/regress@DLSUFFIX@'
-        LANGUAGE C STRICT;
-
-CREATE FUNCTION test_atomic_ops()
-    RETURNS bool
-    AS '@libdir@/regress@DLSUFFIX@'
-    LANGUAGE C;
-
--- Tests creating a FDW handler
-CREATE FUNCTION test_fdw_handler()
-    RETURNS fdw_handler
-    AS '@libdir@/regress@DLSUFFIX@', 'test_fdw_handler'
-    LANGUAGE C;
-
-CREATE FUNCTION test_support_func(internal)
-    RETURNS internal
-    AS '@libdir@/regress@DLSUFFIX@', 'test_support_func'
-    LANGUAGE C STRICT;
-
-CREATE FUNCTION test_opclass_options_func(internal)
-    RETURNS void
-    AS '@libdir@/regress@DLSUFFIX@', 'test_opclass_options_func'
-    LANGUAGE C;
-
-CREATE FUNCTION test_enc_conversion(bytea, name, name, bool, validlen OUT int, result OUT bytea)
-    AS '@libdir@/regress@DLSUFFIX@', 'test_enc_conversion'
-    LANGUAGE C STRICT;
-
 -- Things that shouldn't work:
 
 CREATE FUNCTION test1 (int) RETURNS int LANGUAGE SQL
diff --git a/src/test/regress/output/create_function_0.source b/src/test/regress/output/create_function_0.source
new file mode 100644
index 0000000000..a90049a760
--- /dev/null
+++ b/src/test/regress/output/create_function_0.source
@@ -0,0 +1,35 @@
+--
+-- CREATE_FUNCTION_0
+--
+-- This makes available various test support functions that are in
+-- src/test/regress/regress.c
+-- (although a few more are created in create_function_1)
+--
+CREATE FUNCTION make_tuple_indirect (record)
+    RETURNS record
+    AS '@libdir@/regress@DLSUFFIX@'
+    LANGUAGE C STRICT;
+CREATE FUNCTION test_atomic_ops()
+    RETURNS bool
+    AS '@libdir@/regress@DLSUFFIX@'
+    LANGUAGE C;
+CREATE FUNCTION test_fdw_handler()
+    RETURNS fdw_handler
+    AS '@libdir@/regress@DLSUFFIX@', 'test_fdw_handler'
+    LANGUAGE C;
+CREATE FUNCTION test_support_func(internal)
+    RETURNS internal
+    AS '@libdir@/regress@DLSUFFIX@', 'test_support_func'
+    LANGUAGE C STRICT;
+CREATE FUNCTION test_opclass_options_func(internal)
+    RETURNS void
+    AS '@libdir@/regress@DLSUFFIX@', 'test_opclass_options_func'
+    LANGUAGE C;
+CREATE FUNCTION test_enc_conversion(bytea, name, name, bool,
+                                    validlen OUT int, result OUT bytea)
+    AS '@libdir@/regress@DLSUFFIX@', 'test_enc_conversion'
+    LANGUAGE C STRICT;
+CREATE FUNCTION binary_coercible(oid, oid)
+    RETURNS bool
+    AS '@libdir@/regress@DLSUFFIX@', 'binary_coercible'
+    LANGUAGE C STRICT STABLE PARALLEL SAFE;
diff --git a/src/test/regress/output/create_function_1.source b/src/test/regress/output/create_function_1.source
index c66146db9d..88265779f7 100644
--- a/src/test/regress/output/create_function_1.source
+++ b/src/test/regress/output/create_function_1.source
@@ -47,30 +47,6 @@ CREATE FUNCTION set_ttdummy (int4)
         RETURNS int4
         AS '@libdir@/regress@DLSUFFIX@'
         LANGUAGE C STRICT;
-CREATE FUNCTION make_tuple_indirect (record)
-        RETURNS record
-        AS '@libdir@/regress@DLSUFFIX@'
-        LANGUAGE C STRICT;
-CREATE FUNCTION test_atomic_ops()
-    RETURNS bool
-    AS '@libdir@/regress@DLSUFFIX@'
-    LANGUAGE C;
--- Tests creating a FDW handler
-CREATE FUNCTION test_fdw_handler()
-    RETURNS fdw_handler
-    AS '@libdir@/regress@DLSUFFIX@', 'test_fdw_handler'
-    LANGUAGE C;
-CREATE FUNCTION test_support_func(internal)
-    RETURNS internal
-    AS '@libdir@/regress@DLSUFFIX@', 'test_support_func'
-    LANGUAGE C STRICT;
-CREATE FUNCTION test_opclass_options_func(internal)
-    RETURNS void
-    AS '@libdir@/regress@DLSUFFIX@', 'test_opclass_options_func'
-    LANGUAGE C;
-CREATE FUNCTION test_enc_conversion(bytea, name, name, bool, validlen OUT int, result OUT bytea)
-    AS '@libdir@/regress@DLSUFFIX@', 'test_enc_conversion'
-    LANGUAGE C STRICT;
 -- Things that shouldn't work:
 CREATE FUNCTION test1 (int) RETURNS int LANGUAGE SQL
     AS 'SELECT ''not an integer'';';
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index a091300857..45696031a7 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -24,6 +24,9 @@ test: boolean char name varchar text int2 int4 int8 oid float4 float8 bit numeri
 # ----------
 test: strings numerology point lseg line box path polygon circle date time timetz timestamp timestamptz interval inet macaddr macaddr8 tstypes multirangetypes
 
+# opr_sanity depends on this
+test: create_function_0
+
 # ----------
 # Another group of parallel tests
 # geometry depends on point, lseg, box, path, polygon and circle
diff --git a/src/test/regress/regress.c b/src/test/regress/regress.c
index 1990cbb6a1..d8756e5ba0 100644
--- a/src/test/regress/regress.c
+++ b/src/test/regress/regress.c
@@ -36,6 +36,7 @@
 #include "nodes/supportnodes.h"
 #include "optimizer/optimizer.h"
 #include "optimizer/plancat.h"
+#include "parser/parse_coerce.h"
 #include "port/atomics.h"
 #include "storage/spin.h"
 #include "utils/builtins.h"
@@ -1194,3 +1195,14 @@ test_enc_conversion(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
 }
+
+/* Provide SQL access to IsBinaryCoercible() */
+PG_FUNCTION_INFO_V1(binary_coercible);
+Datum
+binary_coercible(PG_FUNCTION_ARGS)
+{
+	Oid			srctype = PG_GETARG_OID(0);
+	Oid			targettype = PG_GETARG_OID(1);
+
+	PG_RETURN_BOOL(IsBinaryCoercible(srctype, targettype));
+}
diff --git a/src/test/regress/serial_schedule b/src/test/regress/serial_schedule
index 5644847601..bdadb1db29 100644
--- a/src/test/regress/serial_schedule
+++ b/src/test/regress/serial_schedule
@@ -43,6 +43,7 @@ test: inet
 test: macaddr
 test: macaddr8
 test: tstypes
+test: create_function_0
 test: geometry
 test: horology
 test: regex
diff --git a/src/test/regress/sql/.gitignore b/src/test/regress/sql/.gitignore
index 46c8112094..fe14af6ae7 100644
--- a/src/test/regress/sql/.gitignore
+++ b/src/test/regress/sql/.gitignore
@@ -1,5 +1,6 @@
 /constraints.sql
 /copy.sql
+/create_function_0.sql
 /create_function_1.sql
 /create_function_2.sql
 /largeobject.sql
diff --git a/src/test/regress/sql/conversion.sql b/src/test/regress/sql/conversion.sql
index ea85f20ed8..8358682432 100644
--- a/src/test/regress/sql/conversion.sql
+++ b/src/test/regress/sql/conversion.sql
@@ -40,7 +40,7 @@ DROP USER regress_conversion_user;
 --
 
 -- Helper function to test a conversion. Uses the test_enc_conversion function
--- that was created in the create_function_1 test.
+-- that was created in the create_function_0 test.
 create or replace function test_conv(
   input IN bytea,
   src_encoding IN text,
diff --git a/src/test/regress/sql/opr_sanity.sql b/src/test/regress/sql/opr_sanity.sql
index 393acdf8c3..5a9c479692 100644
--- a/src/test/regress/sql/opr_sanity.sql
+++ b/src/test/regress/sql/opr_sanity.sql
@@ -18,65 +18,6 @@
 -- that test creates some bogus operators...
 
 
--- Helper functions to deal with cases where binary-coercible matches are
--- allowed.
-
--- This should match IsBinaryCoercible() in parse_coerce.c.
--- It doesn't currently know about some cases, notably domains, anyelement,
--- anynonarray, anyenum, or record, but it doesn't need to (yet).
-create function binary_coercible(oid, oid) returns bool as $$
-begin
-  if $1 = $2 then return true; end if;
-  if EXISTS(select 1 from pg_catalog.pg_cast where
-            castsource = $1 and casttarget = $2 and
-            castmethod = 'b' and castcontext = 'i')
-  then return true; end if;
-  if $2 = 'pg_catalog.any'::pg_catalog.regtype then return true; end if;
-  if $2 = 'pg_catalog.anyarray'::pg_catalog.regtype then
-    if EXISTS(select 1 from pg_catalog.pg_type where
-              oid = $1 and typelem != 0 and
-              typsubscript = 'pg_catalog.array_subscript_handler'::pg_catalog.regproc)
-    then return true; end if;
-  end if;
-  if $2 = 'pg_catalog.anyrange'::pg_catalog.regtype then
-    if (select typtype from pg_catalog.pg_type where oid = $1) = 'r'
-    then return true; end if;
-  end if;
-  if $2 = 'pg_catalog.anymultirange'::pg_catalog.regtype then
-    if (select typtype from pg_catalog.pg_type where oid = $1) = 'm'
-    then return true; end if;
-  end if;
-  return false;
-end
-$$ language plpgsql strict stable;
-
--- This one ignores castcontext, so it will allow cases where an explicit
--- (but still binary) cast would be required to convert the input type.
--- We don't currently use this for any tests in this file, but it is a
--- reasonable alternative definition for some scenarios.
-create function explicitly_binary_coercible(oid, oid) returns bool as $$
-begin
-  if $1 = $2 then return true; end if;
-  if EXISTS(select 1 from pg_catalog.pg_cast where
-            castsource = $1 and casttarget = $2 and
-            castmethod = 'b')
-  then return true; end if;
-  if $2 = 'pg_catalog.any'::pg_catalog.regtype then return true; end if;
-  if $2 = 'pg_catalog.anyarray'::pg_catalog.regtype then
-    if EXISTS(select 1 from pg_catalog.pg_type where
-              oid = $1 and typelem != 0 and
-              typsubscript = 'pg_catalog.array_subscript_handler'::pg_catalog.regproc)
-    then return true; end if;
-  end if;
-  if $2 = 'pg_catalog.anyrange'::pg_catalog.regtype then
-    if (select typtype from pg_catalog.pg_type where oid = $1) = 'r'
-    then return true; end if;
-  end if;
-  return false;
-end
-$$ language plpgsql strict stable;
-
-
 -- **************** pg_proc ****************
 
 -- Look for illegal values in pg_proc fields.
diff --git a/src/test/regress/sql/type_sanity.sql b/src/test/regress/sql/type_sanity.sql
index 4739aca84a..404c3a2043 100644
--- a/src/test/regress/sql/type_sanity.sql
+++ b/src/test/regress/sql/type_sanity.sql
@@ -465,7 +465,7 @@ FROM pg_range p1 JOIN pg_type t ON t.oid = p1.rngsubtype
 WHERE (rngcollation = 0) != (typcollation = 0);
 
 -- opclass had better be a btree opclass accepting the subtype.
--- We must allow anyarray matches, cf opr_sanity's binary_coercible()
+-- We must allow anyarray matches, cf IsBinaryCoercible()
 
 SELECT p1.rngtypid, p1.rngsubtype, o.opcmethod, o.opcname
 FROM pg_range p1 JOIN pg_opclass o ON o.oid = p1.rngsubopc