Refactor our checks for valid function and aggregate signatures.

pg_proc.c and pg_aggregate.c had near-duplicate copies of the logic
to decide whether a function or aggregate's signature is legal.
This seems like a bad thing even without the problem that the
upcoming "anycompatible" patch would roughly double the complexity
of that logic.  Hence, refactor so that the rules are localized
in new subroutines supplied by parse_coerce.c.  (One could quibble
about just where to add that code, but putting it beside
enforce_generic_type_consistency seems not totally unreasonable.)

The fact that the rules are about to change would mandate some
changes in the wording of the associated error messages in any case.
I ended up spelling things out in a fairly literal fashion in the
errdetail messages, eg "A result of type anyelement requires at
least one input of type anyelement, anyarray, anynonarray, anyenum,
or anyrange."  Perhaps this is overkill, but once there's more than
one subgroup of polymorphic types, people might get confused by
more-abstract messages.

Discussion: https://postgr.es/m/24137.1584139352@sss.pgh.pa.us

1 files changed, 19 insertions, 19 deletions

diff --git a/src/test/regress/expected/polymorphism.out b/src/test/regress/expected/polymorphism.out
index 1271ea4a99..331562de19 100644
--- a/src/test/regress/expected/polymorphism.out
+++ b/src/test/regress/expected/polymorphism.out
@@ -61,7 +61,7 @@ create function polyf(x anyelement) returns anyrange as $$
   select array[x + 1, x + 2]
 $$ language sql;
 ERROR:  cannot determine result data type
-DETAIL:  A function returning "anyrange" must have at least one "anyrange" argument.
+DETAIL:  A result of type anyrange requires at least one input of type anyrange.
 create function polyf(x anyrange) returns anyarray as $$
   select array[lower(x), upper(x)]
 $$ language sql;
@@ -155,7 +155,7 @@ CREATE AGGREGATE myaggp01a(*) (SFUNC = stfnp, STYPE = int4[],
 CREATE AGGREGATE myaggp02a(*) (SFUNC = stfnp, STYPE = anyarray,
   FINALFUNC = ffp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --     N    P
 -- should CREATE
 CREATE AGGREGATE myaggp03a(*) (SFUNC = stfp, STYPE = int4[],
@@ -167,11 +167,11 @@ CREATE AGGREGATE myaggp03b(*) (SFUNC = stfp, STYPE = int4[],
 CREATE AGGREGATE myaggp04a(*) (SFUNC = stfp, STYPE = anyarray,
   FINALFUNC = ffp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 CREATE AGGREGATE myaggp04b(*) (SFUNC = stfp, STYPE = anyarray,
   INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --    Case2 (R = P) && ((B = P) || (B = N))
 --    -------------------------------------
 --    S    tf1      B    tf2
@@ -226,13 +226,13 @@ ERROR:  function tfp(integer[], anyelement) does not exist
 CREATE AGGREGATE myaggp13a(BASETYPE = int, SFUNC = tfnp, STYPE = anyarray,
   FINALFUNC = ffp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --    P    N        N    P
 -- should ERROR: tf2p(anyarray, int) not matched by tf2p(int[],anyelement)
 CREATE AGGREGATE myaggp14a(BASETYPE = int, SFUNC = tf2p, STYPE = anyarray,
   FINALFUNC = ffp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --    P    N        P    N
 -- should ERROR: tfnp(anyarray, anyelement) not matched by tfnp(int[],int)
 CREATE AGGREGATE myaggp15a(BASETYPE = anyelement, SFUNC = tfnp,
@@ -248,21 +248,21 @@ ERROR:  function tf2p(anyarray, anyelement) does not exist
 CREATE AGGREGATE myaggp17a(BASETYPE = int, SFUNC = tf1p, STYPE = anyarray,
   FINALFUNC = ffp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 CREATE AGGREGATE myaggp17b(BASETYPE = int, SFUNC = tf1p, STYPE = anyarray,
   INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --    P    P        N    P
 -- should ERROR: tfp(anyarray, int) not matched by tfp(anyarray, anyelement)
 CREATE AGGREGATE myaggp18a(BASETYPE = int, SFUNC = tfp, STYPE = anyarray,
   FINALFUNC = ffp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 CREATE AGGREGATE myaggp18b(BASETYPE = int, SFUNC = tfp, STYPE = anyarray,
   INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --    P    P        P    N
 -- should ERROR: tf1p(anyarray, anyelement) not matched by tf1p(anyarray, int)
 CREATE AGGREGATE myaggp19a(BASETYPE = anyelement, SFUNC = tf1p,
@@ -292,11 +292,11 @@ CREATE AGGREGATE myaggn01b(*) (SFUNC = stfnp, STYPE = int4[],
 CREATE AGGREGATE myaggn02a(*) (SFUNC = stfnp, STYPE = anyarray,
   FINALFUNC = ffnp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 CREATE AGGREGATE myaggn02b(*) (SFUNC = stfnp, STYPE = anyarray,
   INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --     N    P
 -- should CREATE
 CREATE AGGREGATE myaggn03a(*) (SFUNC = stfp, STYPE = int4[],
@@ -306,7 +306,7 @@ CREATE AGGREGATE myaggn03a(*) (SFUNC = stfp, STYPE = int4[],
 CREATE AGGREGATE myaggn04a(*) (SFUNC = stfp, STYPE = anyarray,
   FINALFUNC = ffnp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --    Case4 (R = N) && ((B = P) || (B = N))
 --    -------------------------------------
 --    S    tf1      B    tf2
@@ -360,21 +360,21 @@ ERROR:  function tfp(integer[], anyelement) does not exist
 CREATE AGGREGATE myaggn13a(BASETYPE = int, SFUNC = tfnp, STYPE = anyarray,
   FINALFUNC = ffnp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 CREATE AGGREGATE myaggn13b(BASETYPE = int, SFUNC = tfnp, STYPE = anyarray,
   INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --    P    N        N    P
 -- should ERROR: tf2p(anyarray, int) not matched by tf2p(int[],anyelement)
 CREATE AGGREGATE myaggn14a(BASETYPE = int, SFUNC = tf2p, STYPE = anyarray,
   FINALFUNC = ffnp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 CREATE AGGREGATE myaggn14b(BASETYPE = int, SFUNC = tf2p, STYPE = anyarray,
   INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --    P    N        P    N
 -- should ERROR: tfnp(anyarray, anyelement) not matched by tfnp(int[],int)
 CREATE AGGREGATE myaggn15a(BASETYPE = anyelement, SFUNC = tfnp,
@@ -396,13 +396,13 @@ ERROR:  function tf2p(anyarray, anyelement) does not exist
 CREATE AGGREGATE myaggn17a(BASETYPE = int, SFUNC = tf1p, STYPE = anyarray,
   FINALFUNC = ffnp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --    P    P        N    P
 -- should ERROR: tfp(anyarray, int) not matched by tfp(anyarray, anyelement)
 CREATE AGGREGATE myaggn18a(BASETYPE = int, SFUNC = tfp, STYPE = anyarray,
   FINALFUNC = ffnp, INITCOND = '{}');
 ERROR:  cannot determine transition data type
-DETAIL:  An aggregate using a polymorphic transition type must have at least one polymorphic argument.
+DETAIL:  A result of type anyarray requires at least one input of type anyelement, anyarray, anynonarray, anyenum, or anyrange.
 --    P    P        P    N
 -- should ERROR: tf1p(anyarray, anyelement) not matched by tf1p(anyarray, int)
 CREATE AGGREGATE myaggn19a(BASETYPE = anyelement, SFUNC = tf1p,