diff --git a/contrib/intarray/_int.sql.in b/contrib/intarray/_int.sql.in
index ee77e784b7..2388fb8cc4 100644
--- a/contrib/intarray/_int.sql.in
+++ b/contrib/intarray/_int.sql.in
@@ -12,12 +12,12 @@ BEGIN;
 CREATE FUNCTION bqarr_in(cstring)
 RETURNS query_int
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE FUNCTION bqarr_out(query_int)
 RETURNS cstring
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE TYPE query_int (
 	INTERNALLENGTH = -1,
@@ -29,20 +29,20 @@ CREATE TYPE query_int (
 CREATE FUNCTION querytree(query_int)
 RETURNS text
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 
 CREATE FUNCTION boolop(_int4, query_int)
 RETURNS bool
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 COMMENT ON FUNCTION boolop(_int4, query_int) IS 'boolean operation with array';
 
 CREATE FUNCTION rboolop(query_int, _int4)
 RETURNS bool
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 COMMENT ON FUNCTION rboolop(query_int, _int4) IS 'boolean operation with array';
 
@@ -74,35 +74,35 @@ CREATE OPERATOR ~~ (
 CREATE FUNCTION _int_contains(_int4, _int4)
 RETURNS bool
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 COMMENT ON FUNCTION _int_contains(_int4, _int4) IS 'contains';
 
 CREATE FUNCTION _int_contained(_int4, _int4)
 RETURNS bool
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 COMMENT ON FUNCTION _int_contained(_int4, _int4) IS 'contained in';
 
 CREATE FUNCTION _int_overlap(_int4, _int4)
 RETURNS bool
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 COMMENT ON FUNCTION _int_overlap(_int4, _int4) IS 'overlaps';
 
 CREATE FUNCTION _int_same(_int4, _int4)
 RETURNS bool
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 COMMENT ON FUNCTION _int_same(_int4, _int4) IS 'same as';
 
 CREATE FUNCTION _int_different(_int4, _int4)
 RETURNS bool
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 COMMENT ON FUNCTION _int_different(_int4, _int4) IS 'different';
 
@@ -111,12 +111,12 @@ COMMENT ON FUNCTION _int_different(_int4, _int4) IS 'different';
 CREATE FUNCTION _int_union(_int4, _int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE FUNCTION _int_inter(_int4, _int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 --
 -- OPERATORS
@@ -194,12 +194,12 @@ CREATE OPERATOR ~ (
 CREATE FUNCTION intset(int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE FUNCTION icount(_int4)
 RETURNS int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE OPERATOR # (
 	RIGHTARG = _int4,
@@ -209,32 +209,32 @@ CREATE OPERATOR # (
 CREATE FUNCTION sort(_int4, text)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE FUNCTION sort(_int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE FUNCTION sort_asc(_int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE FUNCTION sort_desc(_int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE FUNCTION uniq(_int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE FUNCTION idx(_int4, int4)
 RETURNS int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE OPERATOR # (
 	LEFTARG = _int4,
@@ -245,17 +245,17 @@ CREATE OPERATOR # (
 CREATE FUNCTION subarray(_int4, int4, int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE FUNCTION subarray(_int4, int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE FUNCTION intarray_push_elem(_int4, int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE OPERATOR + (
 	LEFTARG = _int4,
@@ -266,7 +266,7 @@ CREATE OPERATOR + (
 CREATE FUNCTION intarray_push_array(_int4, _int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE OPERATOR + (
 	LEFTARG = _int4,
@@ -278,7 +278,7 @@ CREATE OPERATOR + (
 CREATE FUNCTION intarray_del_elem(_int4, int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE OPERATOR - (
 	LEFTARG = _int4,
@@ -289,7 +289,7 @@ CREATE OPERATOR - (
 CREATE FUNCTION intset_union_elem(_int4, int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE OPERATOR | (
 	LEFTARG = _int4,
@@ -307,7 +307,7 @@ CREATE OPERATOR | (
 CREATE FUNCTION intset_subtract(_int4, _int4)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE OPERATOR - (
 	LEFTARG = _int4,
@@ -327,37 +327,37 @@ CREATE OPERATOR & (
 CREATE FUNCTION g_int_consistent(internal,_int4,int4)
 RETURNS bool
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE FUNCTION g_int_compress(internal)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE FUNCTION g_int_decompress(internal)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE FUNCTION g_int_penalty(internal,internal,internal)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT;
+LANGUAGE C IMMUTABLE STRICT;
 
 CREATE FUNCTION g_int_picksplit(internal, internal)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE FUNCTION g_int_union(internal, internal)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE FUNCTION g_int_same(_int4, _int4, internal)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 
 -- Create the operator class for indexing
@@ -388,12 +388,12 @@ DEFAULT FOR TYPE _int4 USING gist AS
 CREATE FUNCTION _intbig_in(cstring)
 RETURNS intbig_gkey
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE FUNCTION _intbig_out(intbig_gkey)
 RETURNS cstring
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+LANGUAGE C STRICT IMMUTABLE;
 
 CREATE TYPE intbig_gkey (
         INTERNALLENGTH = -1,
@@ -404,37 +404,37 @@ CREATE TYPE intbig_gkey (
 CREATE FUNCTION g_intbig_consistent(internal,internal,int4)
 RETURNS bool
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE FUNCTION g_intbig_compress(internal)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE FUNCTION g_intbig_decompress(internal)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE FUNCTION g_intbig_penalty(internal,internal,internal)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C RETURNS NULL ON NULL INPUT;
+LANGUAGE C IMMUTABLE STRICT;
 
 CREATE FUNCTION g_intbig_picksplit(internal, internal)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE FUNCTION g_intbig_union(internal, internal)
 RETURNS _int4
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE FUNCTION g_intbig_same(internal, internal, internal)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 -- register the opclass for indexing (not as default)
 
@@ -462,12 +462,12 @@ AS
 CREATE FUNCTION ginint4_queryextract(internal, internal, int2)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE FUNCTION ginint4_consistent(internal, int2, internal)
 RETURNS internal
 AS 'MODULE_PATHNAME'
-LANGUAGE C;
+LANGUAGE C IMMUTABLE;
 
 CREATE OPERATOR CLASS gin__int_ops
 FOR TYPE _int4 USING gin