Provide more-specific error details/hints for function lookup failures.

Up to now we've contented ourselves with a one-size-fits-all error
hint when we fail to find any match to a function or procedure call.
That was mostly okay in the beginning, but it was never great, and
since the introduction of named arguments it's really not adequate.
We at least ought to distinguish "function name doesn't exist" from
"function name exists, but not with those argument names".  And the
rules for named-argument matching are arcane enough that some more
detail seems warranted if we match the argument names but the call
still doesn't work.

This patch creates a framework for dealing with these problems:
FuncnameGetCandidates and related code will now pass back a bitmask of
flags showing how far the match succeeded.  This allows a considerable
amount of granularity in the reports.  The set-bits-in-a-bitmask
approach means that when there are multiple candidate functions, the
report will reflect the match(es) that got the furthest, which seems
correct.  Also, we can avoid mentioning "maybe add casts" unless
failure to match argument types is actually the issue.

Extend the same return-a-bitmask approach to OpernameGetCandidates.
The issues around argument names don't apply to operator syntax,
but it still seems worth distinguishing between "there is no
operator of that name" and "we couldn't match the argument types".

While at it, adjust these messages and related ones to more strictly
separate "detail" from "hint", following our message style guidelines'
distinction between those.

Reported-by: Dominique Devienne <[email protected]>
Author: Tom Lane <[email protected]>
Reviewed-by: Robert Haas <[email protected]>
Discussion: https://postgr.es/m/[email protected]

24 files changed, 203 insertions, 71 deletions

diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index b33e06a0d3d..a08f115b0e5 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -2041,7 +2041,8 @@ alter table anothertab alter column atcol1 drop default;
 alter table anothertab alter column atcol1 type boolean
         using case when atcol1 % 2 = 0 then true else false end; -- fails
 ERROR:  operator does not exist: boolean <= integer
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 alter table anothertab drop constraint anothertab_chk;
 alter table anothertab drop constraint anothertab_chk; -- fails
 ERROR:  constraint "anothertab_chk" of relation "anothertab" does not exist
diff --git a/src/test/regress/expected/arrays.out b/src/test/regress/expected/arrays.out
index b815473f414..69ea2cf5ad8 100644
--- a/src/test/regress/expected/arrays.out
+++ b/src/test/regress/expected/arrays.out
@@ -2747,7 +2747,8 @@ SELECT width_bucket('5'::text, ARRAY[3, 4]::integer[]);
 ERROR:  function width_bucket(text, integer[]) does not exist
 LINE 1: SELECT width_bucket('5'::text, ARRAY[3, 4]::integer[]);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 SELECT width_bucket(5, ARRAY[3, 4, NULL]);
 ERROR:  thresholds array must not contain NULLs
 SELECT width_bucket(5, ARRAY[ARRAY[1, 2], ARRAY[3, 4]]);
diff --git a/src/test/regress/expected/create_cast.out b/src/test/regress/expected/create_cast.out
index fd4871d94db..0e69644bca2 100644
--- a/src/test/regress/expected/create_cast.out
+++ b/src/test/regress/expected/create_cast.out
@@ -28,14 +28,16 @@ SELECT casttestfunc('foo'::text); -- fails, as there's no cast
 ERROR:  function casttestfunc(text) does not exist
 LINE 1: SELECT casttestfunc('foo'::text);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 -- Try binary coercion cast
 CREATE CAST (text AS casttesttype) WITHOUT FUNCTION;
 SELECT casttestfunc('foo'::text); -- doesn't work, as the cast is explicit
 ERROR:  function casttestfunc(text) does not exist
 LINE 1: SELECT casttestfunc('foo'::text);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 SELECT casttestfunc('foo'::text::casttesttype); -- should work
  casttestfunc 
 --------------
diff --git a/src/test/regress/expected/create_function_sql.out b/src/test/regress/expected/create_function_sql.out
index da112608d66..73c6730d459 100644
--- a/src/test/regress/expected/create_function_sql.out
+++ b/src/test/regress/expected/create_function_sql.out
@@ -304,7 +304,8 @@ CREATE FUNCTION functest_S_xx(x date) RETURNS boolean
 ERROR:  operator does not exist: date > integer
 LINE 3:     RETURN x > 1;
                      ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 -- tricky parsing
 CREATE FUNCTION functest_S_15(x int) RETURNS boolean
 LANGUAGE SQL
diff --git a/src/test/regress/expected/create_operator.out b/src/test/regress/expected/create_operator.out
index d776d9c18c3..5c7159665e2 100644
--- a/src/test/regress/expected/create_operator.out
+++ b/src/test/regress/expected/create_operator.out
@@ -24,6 +24,25 @@ SELECT @#@ 24;
  620448401733239439360000
 (1 row)
 
+-- Test error cases
+select @@##@@ 24;  -- no such operator
+ERROR:  operator does not exist: @@##@@ integer
+LINE 1: select @@##@@ 24;
+               ^
+DETAIL:  There is no operator of that name.
+set search_path = pg_catalog;
+select @#@ 24;  -- wrong schema
+ERROR:  operator does not exist: @#@ integer
+LINE 1: select @#@ 24;
+               ^
+DETAIL:  An operator of that name exists, but it is not in the search_path.
+reset search_path;
+select @#@ 24.0;  -- wrong data type
+ERROR:  operator does not exist: @#@ numeric
+LINE 1: select @#@ 24.0;
+               ^
+DETAIL:  No operator of that name accepts the given argument type.
+HINT:  You might need to add an explicit type cast.
 -- Test comments
 COMMENT ON OPERATOR ###### (NONE, int4) IS 'bad prefix';
 ERROR:  operator does not exist: ###### integer
diff --git a/src/test/regress/expected/create_procedure.out b/src/test/regress/expected/create_procedure.out
index 45b402e25e7..f89042cf798 100644
--- a/src/test/regress/expected/create_procedure.out
+++ b/src/test/regress/expected/create_procedure.out
@@ -2,7 +2,7 @@ CALL nonexistent();  -- error
 ERROR:  procedure nonexistent() does not exist
 LINE 1: CALL nonexistent();
              ^
-HINT:  No procedure matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  There is no procedure of that name.
 CALL random();  -- error
 ERROR:  random() is not a procedure
 LINE 1: CALL random();
@@ -299,7 +299,8 @@ CALL ptest9(1./0.);  -- error
 ERROR:  procedure ptest9(numeric) does not exist
 LINE 1: CALL ptest9(1./0.);
              ^
-HINT:  No procedure matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No procedure of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 -- check named-parameter matching
 CREATE PROCEDURE ptest10(OUT a int, IN b int, IN c int)
 LANGUAGE SQL AS $$ SELECT b - c $$;
diff --git a/src/test/regress/expected/create_view.out b/src/test/regress/expected/create_view.out
index f551624afb3..49dd13c345c 100644
--- a/src/test/regress/expected/create_view.out
+++ b/src/test/regress/expected/create_view.out
@@ -1924,7 +1924,8 @@ select 'foo'::text = any((select array['abc','def','foo']::text[]));  -- fail
 ERROR:  operator does not exist: text = text[]
 LINE 1: select 'foo'::text = any((select array['abc','def','foo']::t...
                            ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select 'foo'::text = any((select array['abc','def','foo']::text[])::text[]);
  ?column? 
 ----------
diff --git a/src/test/regress/expected/domain.out b/src/test/regress/expected/domain.out
index b5ea707df31..62a48a523a2 100644
--- a/src/test/regress/expected/domain.out
+++ b/src/test/regress/expected/domain.out
@@ -415,7 +415,8 @@ select row(0,1)::dcomptype;  -- fail
 ERROR:  value for domain dcomptype violates check constraint "c1"
 alter type comptype alter attribute r type varchar;  -- fail
 ERROR:  operator does not exist: character varying > double precision
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 alter type comptype alter attribute r type bigint;
 alter type comptype drop attribute r;  -- fail
 ERROR:  cannot drop column r of composite type comptype because other objects depend on it
diff --git a/src/test/regress/expected/expressions.out b/src/test/regress/expected/expressions.out
index 21c54fc1989..9a3c97b15a3 100644
--- a/src/test/regress/expected/expressions.out
+++ b/src/test/regress/expected/expressions.out
@@ -218,7 +218,8 @@ select '(0,0)'::point in ('(0,0,0,0)'::box, point(0,0));
 ERROR:  operator does not exist: point = box
 LINE 1: select '(0,0)'::point in ('(0,0,0,0)'::box, point(0,0));
                               ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 --
 -- Tests for ScalarArrayOpExpr with a hashfn
 --
diff --git a/src/test/regress/expected/geometry.out b/src/test/regress/expected/geometry.out
index 8be694f46be..1d168b21cbc 100644
--- a/src/test/regress/expected/geometry.out
+++ b/src/test/regress/expected/geometry.out
@@ -1777,7 +1777,8 @@ SELECT p.f1, l.s, l.s # p.f1 AS intersection
 ERROR:  operator does not exist: lseg # point
 LINE 1: SELECT p.f1, l.s, l.s # p.f1 AS intersection
                               ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 -- Length
 SELECT s, @-@ s FROM LSEG_TBL;
                s               |   ?column?    
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 5ae93d8e8a5..32cf62b6741 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -605,7 +605,8 @@ SELECT date '1991-02-03' - time with time zone '04:05:06 UTC' AS "Subtract Time
 ERROR:  operator does not exist: date - time with time zone
 LINE 1: SELECT date '1991-02-03' - time with time zone '04:05:06 UTC...
                                  ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 --
 -- timestamp, interval arithmetic
 --
diff --git a/src/test/regress/expected/misc_functions.out b/src/test/regress/expected/misc_functions.out
index c3b2b9d8603..36164a99c83 100644
--- a/src/test/regress/expected/misc_functions.out
+++ b/src/test/regress/expected/misc_functions.out
@@ -171,12 +171,12 @@ SELECT num_nonnulls();
 ERROR:  function num_nonnulls() does not exist
 LINE 1: SELECT num_nonnulls();
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given number of arguments.
 SELECT num_nulls();
 ERROR:  function num_nulls() does not exist
 LINE 1: SELECT num_nulls();
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given number of arguments.
 --
 -- canonicalize_path()
 --
diff --git a/src/test/regress/expected/multirangetypes.out b/src/test/regress/expected/multirangetypes.out
index c6363ebeb24..63de4d09b15 100644
--- a/src/test/regress/expected/multirangetypes.out
+++ b/src/test/regress/expected/multirangetypes.out
@@ -3096,7 +3096,8 @@ select multirange_of_text(textrange2('a','Z'));  -- should fail
 ERROR:  function multirange_of_text(textrange2) does not exist
 LINE 1: select multirange_of_text(textrange2('a','Z'));
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select multirange_of_text(textrange1('a','Z')) @> 'b'::text;
 ERROR:  range lower bound must be less than or equal to range upper bound
 select unnest(multirange_of_text(textrange1('a','b'), textrange1('d','e')));
@@ -3160,7 +3161,8 @@ select anyarray_anymultirange_func(ARRAY[1,2], nummultirange(numrange(10,20)));
 ERROR:  function anyarray_anymultirange_func(integer[], nummultirange) does not exist
 LINE 1: select anyarray_anymultirange_func(ARRAY[1,2], nummultirange...
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function anyarray_anymultirange_func(anyarray, anymultirange);
 -- should fail
 create function bogus_func(anyelement)
@@ -3199,7 +3201,8 @@ select multirangetypes_sql(nummultirange(numrange(1,10)), ARRAY[2,20]);  -- matc
 ERROR:  function multirangetypes_sql(nummultirange, integer[]) does not exist
 LINE 1: select multirangetypes_sql(nummultirange(numrange(1,10)), AR...
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 create function anycompatiblearray_anycompatiblemultirange_func(a anycompatiblearray, mr anycompatiblemultirange)
   returns anycompatible as 'select $1[1] + lower($2);' language sql;
 select anycompatiblearray_anycompatiblemultirange_func(ARRAY[1,2], multirange(int4range(10,20)));
@@ -3219,7 +3222,8 @@ select anycompatiblearray_anycompatiblemultirange_func(ARRAY[1.1,2], multirange(
 ERROR:  function anycompatiblearray_anycompatiblemultirange_func(numeric[], int4multirange) does not exist
 LINE 1: select anycompatiblearray_anycompatiblemultirange_func(ARRAY...
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function anycompatiblearray_anycompatiblemultirange_func(anycompatiblearray, anycompatiblemultirange);
 create function anycompatiblerange_anycompatiblemultirange_func(r anycompatiblerange, mr anycompatiblemultirange)
   returns anycompatible as 'select lower($1) + lower($2);' language sql;
@@ -3234,7 +3238,8 @@ select anycompatiblerange_anycompatiblemultirange_func(numrange(1,2), multirange
 ERROR:  function anycompatiblerange_anycompatiblemultirange_func(numrange, int4multirange) does not exist
 LINE 1: select anycompatiblerange_anycompatiblemultirange_func(numra...
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function anycompatiblerange_anycompatiblemultirange_func(anycompatiblerange, anycompatiblemultirange);
 -- should fail
 create function bogus_func(anycompatible)
diff --git a/src/test/regress/expected/plpgsql.out b/src/test/regress/expected/plpgsql.out
index d8ce39dba3c..474be478ce8 100644
--- a/src/test/regress/expected/plpgsql.out
+++ b/src/test/regress/expected/plpgsql.out
@@ -1763,7 +1763,8 @@ select f1(point(3,4));  -- fail for lack of + operator
 ERROR:  operator does not exist: point + integer
 LINE 1: x + 1
           ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 QUERY:  x + 1
 CONTEXT:  PL/pgSQL function f1(anyelement) line 3 at RETURN
 drop function f1(x anyelement);
@@ -1848,7 +1849,8 @@ select f1(int4range(42, 49), 11, 4.5) as fail;  -- range type doesn't fit
 ERROR:  function f1(int4range, integer, numeric) does not exist
 LINE 1: select f1(int4range(42, 49), 11, 4.5) as fail;
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function f1(x anycompatiblerange, y anycompatible, z anycompatible);
 -- fail, can't infer type:
 create function f1(x anycompatible) returns anycompatiblerange as $$
@@ -1902,7 +1904,8 @@ select x, pg_typeof(x), y, pg_typeof(y)
 ERROR:  function f1(integer, numeric[], integer, numeric) does not exist
 LINE 2:   from f1(11, array[1, 2.2], 42, 34.5);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function f1(a anyelement, b anyarray,
                  c anycompatible, d anycompatible);
 --
@@ -3072,7 +3075,7 @@ select shadowtest(1);
 ERROR:  function shadowtest(integer) does not exist
 LINE 1: select shadowtest(1);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  There is no function of that name.
 reset plpgsql.extra_errors;
 reset plpgsql.extra_warnings;
 create or replace function shadowtest(f1 int)
diff --git a/src/test/regress/expected/polymorphism.out b/src/test/regress/expected/polymorphism.out
index 94eedfe375e..4f8447ec0d7 100644
--- a/src/test/regress/expected/polymorphism.out
+++ b/src/test/regress/expected/polymorphism.out
@@ -15,7 +15,8 @@ select polyf(point(3,4));  -- fail for lack of + operator
 ERROR:  operator does not exist: point + integer
 LINE 2:   select x + 1
                    ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 QUERY:  
   select x + 1
 
@@ -95,7 +96,8 @@ select polyf(int4range(42, 49), 11, 4.5) as fail;  -- range type doesn't fit
 ERROR:  function polyf(int4range, integer, numeric) does not exist
 LINE 1: select polyf(int4range(42, 49), 11, 4.5) as fail;
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function polyf(x anycompatiblerange, y anycompatible, z anycompatible);
 create function polyf(x anycompatiblemultirange, y anycompatible, z anycompatible) returns anycompatiblearray as $$
   select array[lower(x), upper(x), y, z]
@@ -110,7 +112,8 @@ select polyf(multirange(int4range(42, 49)), 11, 4.5) as fail;  -- range type doe
 ERROR:  function polyf(int4multirange, integer, numeric) does not exist
 LINE 1: select polyf(multirange(int4range(42, 49)), 11, 4.5) as fail...
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function polyf(x anycompatiblemultirange, y anycompatible, z anycompatible);
 -- fail, can't infer type:
 create function polyf(x anycompatible) returns anycompatiblerange as $$
@@ -176,7 +179,8 @@ select x, pg_typeof(x), y, pg_typeof(y)
 ERROR:  function polyf(integer, numeric[], integer, numeric) does not exist
 LINE 2:   from polyf(11, array[1, 2.2], 42, 34.5);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function polyf(a anyelement, b anyarray,
                     c anycompatible, d anycompatible);
 create function polyf(anyrange) returns anymultirange
@@ -990,7 +994,7 @@ select myleast(); -- fail
 ERROR:  function myleast() does not exist
 LINE 1: select myleast();
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given number of arguments.
 -- test with variadic call parameter
 select myleast(variadic array[1,2,3,4,-1]);
  myleast 
@@ -1060,17 +1064,20 @@ select formarray(1.1, array[1.2,55.5]); -- fail without variadic
 ERROR:  function formarray(numeric, numeric[]) does not exist
 LINE 1: select formarray(1.1, array[1.2,55.5]);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select formarray(1, 'x'::text); -- fail, type mismatch
 ERROR:  function formarray(integer, text) does not exist
 LINE 1: select formarray(1, 'x'::text);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select formarray(1, variadic array['x'::text]); -- fail, type mismatch
 ERROR:  function formarray(integer, text[]) does not exist
 LINE 1: select formarray(1, variadic array['x'::text]);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function formarray(anyelement, variadic anyarray);
 -- test pg_typeof() function
 select pg_typeof(null);           -- unknown
@@ -1154,7 +1161,7 @@ select dfunc(10, 20, 30);  -- fail
 ERROR:  function dfunc(integer, integer, integer) does not exist
 LINE 1: select dfunc(10, 20, 30);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given number of arguments.
 drop function dfunc();  -- fail
 ERROR:  function dfunc() does not exist
 drop function dfunc(int);  -- fail
@@ -1203,7 +1210,8 @@ select dfunc();  -- fail: which dfunc should be called? int or text
 ERROR:  function dfunc() is not unique
 LINE 1: select dfunc();
                ^
-HINT:  Could not choose a best candidate function. You might need to add explicit type casts.
+DETAIL:  Could not choose a best candidate function.
+HINT:  You might need to add explicit type casts.
 select dfunc('Hi');  -- ok
    dfunc   
 -----------
@@ -1242,17 +1250,20 @@ select dfunc();  -- fail
 ERROR:  function dfunc() is not unique
 LINE 1: select dfunc();
                ^
-HINT:  Could not choose a best candidate function. You might need to add explicit type casts.
+DETAIL:  Could not choose a best candidate function.
+HINT:  You might need to add explicit type casts.
 select dfunc(1);  -- fail
 ERROR:  function dfunc(integer) is not unique
 LINE 1: select dfunc(1);
                ^
-HINT:  Could not choose a best candidate function. You might need to add explicit type casts.
+DETAIL:  Could not choose a best candidate function.
+HINT:  You might need to add explicit type casts.
 select dfunc(1, 2);  -- fail
 ERROR:  function dfunc(integer, integer) is not unique
 LINE 1: select dfunc(1, 2);
                ^
-HINT:  Could not choose a best candidate function. You might need to add explicit type casts.
+DETAIL:  Could not choose a best candidate function.
+HINT:  You might need to add explicit type casts.
 select dfunc(1, 2, 3);  -- ok
  dfunc 
 -------
@@ -1310,7 +1321,7 @@ select dfunc();  -- fail
 ERROR:  function dfunc() does not exist
 LINE 1: select dfunc();
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given number of arguments.
 select dfunc(10);
  dfunc 
 -------
@@ -1371,7 +1382,8 @@ select dfunc(1);  -- fail
 ERROR:  function dfunc(integer) is not unique
 LINE 1: select dfunc(1);
                ^
-HINT:  Could not choose a best candidate function. You might need to add explicit type casts.
+DETAIL:  Could not choose a best candidate function.
+HINT:  You might need to add explicit type casts.
 -- but this works since the ambiguous functions aren't preferred anyway
 select dfunc('Hi');
  dfunc 
@@ -1417,7 +1429,7 @@ select * from dfunc(0);  -- fail
 ERROR:  function dfunc(integer) does not exist
 LINE 1: select * from dfunc(0);
                       ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given number of arguments.
 select * from dfunc(1,2);
  a | b | c | d 
 ---+---+---+---
@@ -1448,18 +1460,72 @@ select * from dfunc(x := 10, b := 20, c := 30);  -- fail, unknown param
 ERROR:  function dfunc(x => integer, b => integer, c => integer) does not exist
 LINE 1: select * from dfunc(x := 10, b := 20, c := 30);
                       ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument names.
 select * from dfunc(10, 10, a := 20);  -- fail, a overlaps positional parameter
 ERROR:  function dfunc(integer, integer, a => integer) does not exist
 LINE 1: select * from dfunc(10, 10, a := 20);
                       ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  In the closest available match, an argument was specified both positionally and by name.
 select * from dfunc(1,c := 2,d := 3); -- fail, no value for b
 ERROR:  function dfunc(integer, c => integer, d => integer) does not exist
 LINE 1: select * from dfunc(1,c := 2,d := 3);
                       ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  In the closest available match, not all required arguments were supplied.
 drop function dfunc(int, int, int, int);
+create function xleast(x numeric, variadic arr numeric[])
+  returns numeric as $$
+  select least(x, min(arr[i])) from generate_subscripts(arr, 1) g(i);
+$$ language sql;
+select xleast(x => 1, variadic arr => array[2,3]);
+ xleast 
+--------
+      1
+(1 row)
+
+select xleast(1, variadic arr => array[2,3]);
+ xleast 
+--------
+      1
+(1 row)
+
+set search_path = pg_catalog;
+select xleast(1, variadic arr => array[2,3]);  -- wrong schema
+ERROR:  function xleast(integer, arr => integer[]) does not exist
+LINE 1: select xleast(1, variadic arr => array[2,3]);
+               ^
+DETAIL:  A function of that name exists, but it is not in the search_path.
+reset search_path;
+select xleast(foo => 1, variadic arr => array[2,3]);  -- wrong argument name
+ERROR:  function xleast(foo => integer, arr => integer[]) does not exist
+LINE 1: select xleast(foo => 1, variadic arr => array[2,3]);
+               ^
+DETAIL:  No function of that name accepts the given argument names.
+select xleast(x => 1, variadic array[2,3]);  -- misuse of mixed notation
+ERROR:  positional argument cannot follow named argument
+LINE 1: select xleast(x => 1, variadic array[2,3]);
+                                       ^
+select xleast(1, variadic x => array[2,3]);  -- misuse of mixed notation
+ERROR:  function xleast(integer, x => integer[]) does not exist
+LINE 1: select xleast(1, variadic x => array[2,3]);
+               ^
+DETAIL:  In the closest available match, an argument was specified both positionally and by name.
+select xleast(arr => array[1], variadic x => 3);  -- wrong arg is VARIADIC
+ERROR:  function xleast(arr => integer[], x => integer) does not exist
+LINE 1: select xleast(arr => array[1], variadic x => 3);
+               ^
+HINT:  The VARIADIC parameter must be placed last, even when using argument names.
+select xleast(arr => array[1], x => 3);  -- failed to use VARIADIC
+ERROR:  function xleast(arr => integer[], x => integer) does not exist
+LINE 1: select xleast(arr => array[1], x => 3);
+               ^
+HINT:  This call would be correct if the variadic array were labeled VARIADIC and placed last.
+select xleast(arr => 1, variadic x => array[2,3]);  -- mixed-up args
+ERROR:  function xleast(arr => integer, x => integer[]) does not exist
+LINE 1: select xleast(arr => 1, variadic x => array[2,3]);
+               ^
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
+drop function xleast(x numeric, variadic arr numeric[]);
 -- test with different parameter types
 create function dfunc(a varchar, b numeric, c date = current_date)
   returns table (a varchar, b numeric, c date) as $$
@@ -1499,7 +1565,8 @@ select * from dfunc('Hello World', c := 20, b := '2009-07-25'::date);  -- fail
 ERROR:  function dfunc(unknown, c => integer, b => date) does not exist
 LINE 1: select * from dfunc('Hello World', c := 20, b := '2009-07-25...
                       ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function dfunc(varchar, numeric, date);
 -- test out parameters with named params
 create function dfunc(a varchar = 'def a', out _a varchar, c numeric = NULL, out _c numeric)
@@ -1844,7 +1911,8 @@ select x, pg_typeof(x) from anyctest(11, point(1,2)) x;  -- fail
 ERROR:  function anyctest(integer, point) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(11, point(1,2)) x;
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select x, pg_typeof(x) from anyctest('11', '12.3') x;  -- defaults to text
   x   | pg_typeof 
 ------+-----------
@@ -1872,7 +1940,8 @@ select x, pg_typeof(x) from anyctest(11, array[1,2]) x;  -- fail
 ERROR:  function anyctest(integer, integer[]) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(11, array[1,2]) x;
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function anyctest(anycompatible, anycompatible);
 create function anyctest(anycompatible, anycompatiblearray)
 returns anycompatiblearray as $$
@@ -1906,12 +1975,14 @@ select x, pg_typeof(x) from anyctest(11, array[point(1,2)]) x;  -- fail
 ERROR:  function anyctest(integer, point[]) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(11, array[point(1,2)]) ...
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select x, pg_typeof(x) from anyctest(11, 12) x;  -- fail
 ERROR:  function anyctest(integer, integer) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(11, 12) x;
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function anyctest(anycompatible, anycompatiblearray);
 create function anyctest(anycompatible, anycompatiblerange)
 returns anycompatiblerange as $$
@@ -1933,12 +2004,14 @@ select x, pg_typeof(x) from anyctest(11, 12) x;  -- fail
 ERROR:  function anyctest(integer, integer) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(11, 12) x;
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select x, pg_typeof(x) from anyctest(11.2, int4range(4,7)) x;  -- fail
 ERROR:  function anyctest(numeric, int4range) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(11.2, int4range(4,7)) x...
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select x, pg_typeof(x) from anyctest(11.2, '[4,7)') x;  -- fail
 ERROR:  could not determine polymorphic type anycompatiblerange because input has type unknown
 drop function anyctest(anycompatible, anycompatiblerange);
@@ -1956,7 +2029,8 @@ select x, pg_typeof(x) from anyctest(int4range(11,12), numrange(4,7)) x; -- fail
 ERROR:  function anyctest(int4range, numrange) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(int4range(11,12), numra...
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function anyctest(anycompatiblerange, anycompatiblerange);
 -- fail, can't infer result type:
 create function anyctest(anycompatible)
@@ -1985,12 +2059,14 @@ select x, pg_typeof(x) from anyctest(11, 12) x;  -- fail
 ERROR:  function anyctest(integer, integer) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(11, 12) x;
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select x, pg_typeof(x) from anyctest(11.2, multirange(int4range(4,7))) x;  -- fail
 ERROR:  function anyctest(numeric, int4multirange) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(11.2, multirange(int4ra...
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select x, pg_typeof(x) from anyctest(11.2, '{[4,7)}') x;  -- fail
 ERROR:  could not determine polymorphic type anycompatiblemultirange because input has type unknown
 drop function anyctest(anycompatible, anycompatiblemultirange);
@@ -2008,7 +2084,8 @@ select x, pg_typeof(x) from anyctest(multirange(int4range(11,12)), multirange(nu
 ERROR:  function anyctest(int4multirange, nummultirange) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(multirange(int4range(11...
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function anyctest(anycompatiblemultirange, anycompatiblemultirange);
 -- fail, can't infer result type:
 create function anyctest(anycompatible)
@@ -2037,7 +2114,8 @@ select x, pg_typeof(x) from anyctest(array[11], array[1,2]) x;  -- fail
 ERROR:  function anyctest(integer[], integer[]) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(array[11], array[1,2]) ...
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function anyctest(anycompatiblenonarray, anycompatiblenonarray);
 create function anyctest(a anyelement, b anyarray,
                          c anycompatible, d anycompatible)
@@ -2066,7 +2144,8 @@ select x, pg_typeof(x) from anyctest(11, array[1, 2.2], 42, 34.5) x;  -- fail
 ERROR:  function anyctest(integer, numeric[], integer, numeric) does not exist
 LINE 1: select x, pg_typeof(x) from anyctest(11, array[1, 2.2], 42, ...
                                     ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function anyctest(a anyelement, b anyarray,
                        c anycompatible, d anycompatible);
 create function anyctest(variadic anycompatiblearray)
diff --git a/src/test/regress/expected/rangetypes.out b/src/test/regress/expected/rangetypes.out
index a7cc220bf0d..cdd95799cd5 100644
--- a/src/test/regress/expected/rangetypes.out
+++ b/src/test/regress/expected/rangetypes.out
@@ -1630,7 +1630,8 @@ select anyarray_anyrange_func(ARRAY[1,2], numrange(10,20));
 ERROR:  function anyarray_anyrange_func(integer[], numrange) does not exist
 LINE 1: select anyarray_anyrange_func(ARRAY[1,2], numrange(10,20));
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function anyarray_anyrange_func(anyarray, anyrange);
 -- should fail
 create function bogus_func(anyelement)
@@ -1669,7 +1670,8 @@ select rangetypes_sql(numrange(1,10), ARRAY[2,20]);  -- match failure
 ERROR:  function rangetypes_sql(numrange, integer[]) does not exist
 LINE 1: select rangetypes_sql(numrange(1,10), ARRAY[2,20]);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 create function anycompatiblearray_anycompatiblerange_func(a anycompatiblearray, r anycompatiblerange)
   returns anycompatible as 'select $1[1] + lower($2);' language sql;
 select anycompatiblearray_anycompatiblerange_func(ARRAY[1,2], int4range(10,20));
@@ -1689,7 +1691,8 @@ select anycompatiblearray_anycompatiblerange_func(ARRAY[1.1,2], int4range(10,20)
 ERROR:  function anycompatiblearray_anycompatiblerange_func(numeric[], int4range) does not exist
 LINE 1: select anycompatiblearray_anycompatiblerange_func(ARRAY[1.1,...
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 drop function anycompatiblearray_anycompatiblerange_func(anycompatiblearray, anycompatiblerange);
 -- should fail
 create function bogus_func(anycompatible)
diff --git a/src/test/regress/expected/rowtypes.out b/src/test/regress/expected/rowtypes.out
index 9168979a620..d84122881af 100644
--- a/src/test/regress/expected/rowtypes.out
+++ b/src/test/regress/expected/rowtypes.out
@@ -965,7 +965,8 @@ select text(fullname) from fullname;  -- error
 ERROR:  function text(fullname) does not exist
 LINE 1: select text(fullname) from fullname;
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select fullname.text from fullname;  -- error
 ERROR:  column fullname.text does not exist
 LINE 1: select fullname.text from fullname;
@@ -987,7 +988,8 @@ select text(row('Jim', 'Beam'));  -- error
 ERROR:  function text(record) does not exist
 LINE 1: select text(row('Jim', 'Beam'));
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select (row('Jim', 'Beam')).text;  -- error
 ERROR:  could not identify column "text" in record data type
 LINE 1: select (row('Jim', 'Beam')).text;
diff --git a/src/test/regress/expected/subselect.out b/src/test/regress/expected/subselect.out
index 307e5ca1f3d..76ffb2b9027 100644
--- a/src/test/regress/expected/subselect.out
+++ b/src/test/regress/expected/subselect.out
@@ -1175,7 +1175,8 @@ select * from int8_tbl where q1 in (select c1 from inner_text);
 ERROR:  operator does not exist: bigint = text
 LINE 1: select * from int8_tbl where q1 in (select c1 from inner_tex...
                                         ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 begin;
 -- make an operator to allow it to succeed
 create function bogus_int8_text_eq(int8, text) returns boolean
diff --git a/src/test/regress/expected/temp.out b/src/test/regress/expected/temp.out
index 370361543b3..a50c7ae88a9 100644
--- a/src/test/regress/expected/temp.out
+++ b/src/test/regress/expected/temp.out
@@ -229,7 +229,7 @@ select nonempty('');
 ERROR:  function nonempty(unknown) does not exist
 LINE 1: select nonempty('');
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  There is no function of that name.
 select pg_temp.nonempty('');
 ERROR:  value for domain nonempty violates check constraint "nonempty_check"
 -- other syntax matches rules for tables
diff --git a/src/test/regress/expected/text.out b/src/test/regress/expected/text.out
index 4c65b238e76..3f9982388ba 100644
--- a/src/test/regress/expected/text.out
+++ b/src/test/regress/expected/text.out
@@ -27,7 +27,8 @@ select length(42);
 ERROR:  function length(integer) does not exist
 LINE 1: select length(42);
                ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No function of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 -- But as a special exception for usability's sake, we still allow implicit
 -- casting to text in concatenations, so long as the other input is text or
 -- an unknown literal.  So these work:
@@ -48,7 +49,8 @@ select 3 || 4.0;
 ERROR:  operator does not exist: integer || numeric
 LINE 1: select 3 || 4.0;
                  ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 /*
  * various string functions
  */
diff --git a/src/test/regress/expected/time.out b/src/test/regress/expected/time.out
index 4247fae9412..765adeb6e51 100644
--- a/src/test/regress/expected/time.out
+++ b/src/test/regress/expected/time.out
@@ -157,7 +157,8 @@ SELECT f1 + time '00:01' AS "Illegal" FROM TIME_TBL;
 ERROR:  operator is not unique: time without time zone + time without time zone
 LINE 1: SELECT f1 + time '00:01' AS "Illegal" FROM TIME_TBL;
                   ^
-HINT:  Could not choose a best candidate operator. You might need to add explicit type casts.
+DETAIL:  Could not choose a best candidate operator.
+HINT:  You might need to add explicit type casts.
 --
 -- test EXTRACT
 --
diff --git a/src/test/regress/expected/timetz.out b/src/test/regress/expected/timetz.out
index cbab6cfe5d7..324b1a740e8 100644
--- a/src/test/regress/expected/timetz.out
+++ b/src/test/regress/expected/timetz.out
@@ -174,7 +174,8 @@ SELECT f1 + time with time zone '00:01' AS "Illegal" FROM TIMETZ_TBL;
 ERROR:  operator does not exist: time with time zone + time with time zone
 LINE 1: SELECT f1 + time with time zone '00:01' AS "Illegal" FROM TI...
                   ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 --
 -- test EXTRACT
 --
diff --git a/src/test/regress/expected/with.out b/src/test/regress/expected/with.out
index 26c88505140..f015e997276 100644
--- a/src/test/regress/expected/with.out
+++ b/src/test/regress/expected/with.out
@@ -175,7 +175,8 @@ SELECT n, pg_typeof(n) FROM t;
 ERROR:  operator does not exist: text + integer
 LINE 4:     SELECT n+1 FROM t WHERE n < 10
                     ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 -- Deeply nested WITH caused a list-munging problem in v13
 -- Detection of cross-references and self-references
 WITH RECURSIVE w1(c1) AS
diff --git a/src/test/regress/expected/xid.out b/src/test/regress/expected/xid.out
index 835077e9d57..1ce7826cf90 100644
--- a/src/test/regress/expected/xid.out
+++ b/src/test/regress/expected/xid.out
@@ -110,22 +110,26 @@ select '1'::xid < '2'::xid;
 ERROR:  operator does not exist: xid < xid
 LINE 1: select '1'::xid < '2'::xid;
                         ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select '1'::xid <= '2'::xid;
 ERROR:  operator does not exist: xid <= xid
 LINE 1: select '1'::xid <= '2'::xid;
                         ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select '1'::xid > '2'::xid;
 ERROR:  operator does not exist: xid > xid
 LINE 1: select '1'::xid > '2'::xid;
                         ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 select '1'::xid >= '2'::xid;
 ERROR:  operator does not exist: xid >= xid
 LINE 1: select '1'::xid >= '2'::xid;
                         ^
-HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.
+DETAIL:  No operator of that name accepts the given argument types.
+HINT:  You might need to add explicit type casts.
 -- we want them for xid8 though
 select '1'::xid8 < '2'::xid8, '2'::xid8 < '2'::xid8, '2'::xid8 < '1'::xid8;
  ?column? | ?column? | ?column?