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 <ddevienne@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/1756041.1754616558@sss.pgh.pa.us

contrib/postgres_fdw/expected/postgres_fdw.out

@@ -4609,11 +4609,13 @@ SELECT * FROM ft1 WHERE 'foo' = c8 LIMIT 1;
 -- with that remote type
 SELECT * FROM ft1 WHERE c8 LIKE 'foo' LIMIT 1; -- ERROR
 ERROR:  operator does not exist: public.user_enum ~~ unknown
-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.
 CONTEXT:  remote SQL command: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c8 ~~ 'foo')) LIMIT 1::bigint
 SELECT * FROM ft1 WHERE c8::text LIKE 'foo' LIMIT 1; -- ERROR; cast not pushed down
 ERROR:  operator does not exist: public.user_enum ~~ unknown
-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.
 CONTEXT:  remote SQL command: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c8 ~~ 'foo')) LIMIT 1::bigint
 ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE user_enum;
 -- ===================================================================

doc/src/sgml/sources.sgml

@@ -153,11 +153,12 @@ ereport(ERROR,
         errmsg("function %s is not unique",
                func_signature_string(funcname, nargs,
                                      NIL, actual_arg_types)),
-        errhint("Unable to choose a best candidate function. "
-                "You might need to add explicit typecasts."));
+        errdetail("Could not choose a best candidate function."),
+        errhint("You might need to add explicit type casts."));
 </programlisting>
     This illustrates the use of format codes to embed run-time values into
-    a message text.  Also, an optional <quote>hint</quote> message is provided.
+    a message text.  Also, optional <quote>detail</quote>
+    and <quote>hint</quote> messages are provided.
     The auxiliary function calls can be written in any order, but
     conventionally <function>errcode</function>
     and <function>errmsg</function> appear first.

doc/src/sgml/typeconv.sgml

@@ -465,9 +465,9 @@ try a similar case with <literal>~</literal>, we get:
 <screen>
 SELECT ~ '20' AS "negation";
 
-ERROR:  operator is not unique: ~ "unknown"
-HINT:  Could not choose a best candidate operator. You might need to add
-explicit type casts.
+ERROR:  operator is not unique: ~ unknown
+DETAIL:  Could not choose a best candidate operator.
+HINT:  You might need to add explicit type casts.
 </screen>
 This happens because the system cannot decide which of the several
 possible <literal>~</literal> operators should be preferred.  We can help
@@ -901,8 +901,8 @@ the parser will try to convert that to <type>text</type>:
 <screen>
 SELECT substr(1234, 3);
 ERROR:  function substr(integer, integer) does not exist
-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.
 </screen>
 
 This does not work because <type>integer</type> does not have an implicit cast

src/backend/catalog/namespace.c

@@ -232,7 +232,7 @@ static void RemoveTempRelationsCallback(int code, Datum arg);
 static void InvalidationCallback(Datum arg, int cacheid, uint32 hashvalue);
 static bool MatchNamedCall(HeapTuple proctup, int nargs, List *argnames,
 						   bool include_out_arguments, int pronargs,
-						   int **argnumbers);
+						   int **argnumbers, int *fgc_flags);
 
 /*
  * Recomputing the namespace path can be costly when done frequently, such as
@@ -1117,15 +1117,15 @@ TypeIsVisibleExt(Oid typid, bool *is_missing)
 
 /*
  * FuncnameGetCandidates
- *		Given a possibly-qualified function name and argument count,
+ *		Given a possibly-qualified routine name, argument count, and arg names,
  *		retrieve a list of the possible matches.
  *
- * If nargs is -1, we return all functions matching the given name,
+ * If nargs is -1, we return all routines matching the given name,
  * regardless of argument count.  (argnames must be NIL, and expand_variadic
  * and expand_defaults must be false, in this case.)
  *
  * If argnames isn't NIL, we are considering a named- or mixed-notation call,
- * and only functions having all the listed argument names will be returned.
+ * and only routines having all the listed argument names will be returned.
  * (We assume that length(argnames) <= nargs and all the passed-in names are
  * distinct.)  The returned structs will include an argnumbers array showing
  * the actual argument index for each logical argument position.
@@ -1183,14 +1183,21 @@ TypeIsVisibleExt(Oid typid, bool *is_missing)
  * The caller might end up discarding such an entry anyway, but if it selects
  * such an entry it should react as though the call were ambiguous.
  *
- * If missing_ok is true, an empty list (NULL) is returned if the name was
- * schema-qualified with a schema that does not exist.  Likewise if no
- * candidate is found for other reasons.
+ * We return an empty list (NULL) if no suitable matches can be found.
+ * If the function name was schema-qualified with a schema that does not
+ * exist, then we return an empty list if missing_ok is true and otherwise
+ * throw an error.  (missing_ok does not affect the behavior otherwise.)
+ *
+ * The output argument *fgc_flags is filled with a bitmask indicating how
+ * far we were able to match the supplied information.  This is not of much
+ * interest if any candidates were found, but if not, it can help callers
+ * produce an on-point error message.
  */
 FuncCandidateList
 FuncnameGetCandidates(List *names, int nargs, List *argnames,
 					  bool expand_variadic, bool expand_defaults,
-					  bool include_out_arguments, bool missing_ok)
+					  bool include_out_arguments, bool missing_ok,
+					  int *fgc_flags)
 {
 	FuncCandidateList resultList = NULL;
 	bool		any_special = false;
@@ -1203,15 +1210,20 @@ FuncnameGetCandidates(List *names, int nargs, List *argnames,
 	/* check for caller error */
 	Assert(nargs >= 0 || !(expand_variadic | expand_defaults));
 
+	/* initialize output fgc_flags to empty */
+	*fgc_flags = 0;
+
 	/* deconstruct the name list */
 	DeconstructQualifiedName(names, &schemaname, &funcname);
 
 	if (schemaname)
 	{
 		/* use exact schema given */
+		*fgc_flags |= FGC_SCHEMA_GIVEN; /* report that a schema is given */
 		namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
 		if (!OidIsValid(namespaceId))
 			return NULL;
+		*fgc_flags |= FGC_SCHEMA_EXISTS;	/* report that the schema exists */
 	}
 	else
 	{
@@ -1237,6 +1249,8 @@ FuncnameGetCandidates(List *names, int nargs, List *argnames,
 		int		   *argnumbers = NULL;
 		FuncCandidateList newResult;
 
+		*fgc_flags |= FGC_NAME_EXISTS;	/* the name is present in pg_proc */
+
 		if (OidIsValid(namespaceId))
 		{
 			/* Consider only procs in specified namespace */
@@ -1262,6 +1276,8 @@ FuncnameGetCandidates(List *names, int nargs, List *argnames,
 				continue;		/* proc is not in search path */
 		}
 
+		*fgc_flags |= FGC_NAME_VISIBLE; /* routine is in the right schema */
+
 		/*
 		 * If we are asked to match to OUT arguments, then use the
 		 * proallargtypes array (which includes those); otherwise use
@@ -1296,16 +1312,6 @@ FuncnameGetCandidates(List *names, int nargs, List *argnames,
 			/*
 			 * Call uses named or mixed notation
 			 *
-			 * Named or mixed notation can match a variadic function only if
-			 * expand_variadic is off; otherwise there is no way to match the
-			 * presumed-nameless parameters expanded from the variadic array.
-			 */
-			if (OidIsValid(procform->provariadic) && expand_variadic)
-				continue;
-			va_elem_type = InvalidOid;
-			variadic = false;
-
-			/*
 			 * Check argument count.
 			 */
 			Assert(nargs >= 0); /* -1 not supported with argnames */
@@ -1324,11 +1330,32 @@ FuncnameGetCandidates(List *names, int nargs, List *argnames,
 			if (pronargs != nargs && !use_defaults)
 				continue;
 
+			/* We found a routine with a suitable number of arguments */
+			*fgc_flags |= FGC_ARGCOUNT_MATCH;
+
 			/* Check for argument name match, generate positional mapping */
 			if (!MatchNamedCall(proctup, nargs, argnames,
 								include_out_arguments, pronargs,
-								&argnumbers))
+								&argnumbers, fgc_flags))
+				continue;
+
+			/*
+			 * Named or mixed notation can match a variadic function only if
+			 * expand_variadic is off; otherwise there is no way to match the
+			 * presumed-nameless parameters expanded from the variadic array.
+			 * However, we postpone the check until here because we want to
+			 * perform argument name matching anyway (using the variadic array
+			 * argument's name).  This allows us to give an on-point error
+			 * message if the user forgets to say VARIADIC in what would have
+			 * been a valid call with it.
+			 */
+			if (OidIsValid(procform->provariadic) && expand_variadic)
 				continue;
+			va_elem_type = InvalidOid;
+			variadic = false;
+
+			/* We found a fully-valid call using argument names */
+			*fgc_flags |= FGC_ARGNAMES_VALID;
 
 			/* Named argument matching is always "special" */
 			any_special = true;
@@ -1371,6 +1398,9 @@ FuncnameGetCandidates(List *names, int nargs, List *argnames,
 			/* Ignore if it doesn't match requested argument count */
 			if (nargs >= 0 && pronargs != nargs && !variadic && !use_defaults)
 				continue;
+
+			/* We found a routine with a suitable number of arguments */
+			*fgc_flags |= FGC_ARGCOUNT_MATCH;
 		}
 
 		/*
@@ -1579,11 +1609,13 @@ FuncnameGetCandidates(List *names, int nargs, List *argnames,
  * the mapping from call argument positions to actual function argument
  * numbers.  Defaulted arguments are included in this map, at positions
  * after the last supplied argument.
+ *
+ * We also add flag bits to *fgc_flags reporting on how far the match got.
  */
 static bool
 MatchNamedCall(HeapTuple proctup, int nargs, List *argnames,
 			   bool include_out_arguments, int pronargs,
-			   int **argnumbers)
+			   int **argnumbers, int *fgc_flags)
 {
 	Form_pg_proc procform = (Form_pg_proc) GETSTRUCT(proctup);
 	int			numposargs = nargs - list_length(argnames);
@@ -1592,6 +1624,7 @@ MatchNamedCall(HeapTuple proctup, int nargs, List *argnames,
 	char	  **p_argnames;
 	char	   *p_argmodes;
 	bool		arggiven[FUNC_MAX_ARGS];
+	bool		arg_filled_twice = false;
 	bool		isnull;
 	int			ap;				/* call args position */
 	int			pp;				/* proargs position */
@@ -1645,9 +1678,9 @@ MatchNamedCall(HeapTuple proctup, int nargs, List *argnames,
 				continue;
 			if (p_argnames[i] && strcmp(p_argnames[i], argname) == 0)
 			{
-				/* fail if argname matches a positional argument */
+				/* note if argname matches a positional argument */
 				if (arggiven[pp])
-					return false;
+					arg_filled_twice = true;
 				arggiven[pp] = true;
 				(*argnumbers)[ap] = pp;
 				found = true;
@@ -1664,6 +1697,16 @@ MatchNamedCall(HeapTuple proctup, int nargs, List *argnames,
 
 	Assert(ap == nargs);		/* processed all actual parameters */
 
+	/* If we get here, the function did match all the supplied argnames */
+	*fgc_flags |= FGC_ARGNAMES_MATCH;
+
+	/* ... however, some of them might have been placed wrong */
+	if (arg_filled_twice)
+		return false;			/* some argname matched a positional argument */
+
+	/* If we get here, the call doesn't have invalid mixed notation */
+	*fgc_flags |= FGC_ARGNAMES_NONDUP;
+
 	/* Check for default arguments */
 	if (nargs < pronargs)
 	{
@@ -1682,6 +1725,9 @@ MatchNamedCall(HeapTuple proctup, int nargs, List *argnames,
 
 	Assert(ap == pronargs);		/* processed all function parameters */
 
+	/* If we get here, the call supplies all the required arguments */
+	*fgc_flags |= FGC_ARGNAMES_ALL;
+
 	return true;
 }
 
@@ -1745,11 +1791,13 @@ FunctionIsVisibleExt(Oid funcid, bool *is_missing)
 		char	   *proname = NameStr(procform->proname);
 		int			nargs = procform->pronargs;
 		FuncCandidateList clist;
+		int			fgc_flags;
 
 		visible = false;
 
 		clist = FuncnameGetCandidates(list_make1(makeString(proname)),
-									  nargs, NIL, false, false, false, false);
+									  nargs, NIL, false, false, false, false,
+									  &fgc_flags);
 
 		for (; clist; clist = clist->next)
 		{
@@ -1882,9 +1930,20 @@ OpernameGetOprid(List *names, Oid oprleft, Oid oprright)
  *
  * The returned items always have two args[] entries --- the first will be
  * InvalidOid for a prefix oprkind.  nargs is always 2, too.
+ *
+ * We return an empty list (NULL) if no suitable matches can be found.  If the
+ * operator name was schema-qualified with a schema that does not exist, then
+ * we return an empty list if missing_schema_ok is true and otherwise throw an
+ * error.  (missing_schema_ok does not affect the behavior otherwise.)
+ *
+ * The output argument *fgc_flags is filled with a bitmask indicating how
+ * far we were able to match the supplied information.  This is not of much
+ * interest if any candidates were found, but if not, it can help callers
+ * produce an on-point error message.
  */
 FuncCandidateList
-OpernameGetCandidates(List *names, char oprkind, bool missing_schema_ok)
+OpernameGetCandidates(List *names, char oprkind, bool missing_schema_ok,
+					  int *fgc_flags)
 {
 	FuncCandidateList resultList = NULL;
 	char	   *resultSpace = NULL;
@@ -1895,15 +1954,20 @@ OpernameGetCandidates(List *names, char oprkind, bool missing_schema_ok)
 	CatCList   *catlist;
 	int			i;
 
+	/* initialize output fgc_flags to empty */
+	*fgc_flags = 0;
+
 	/* deconstruct the name list */
 	DeconstructQualifiedName(names, &schemaname, &opername);
 
 	if (schemaname)
 	{
 		/* use exact schema given */
+		*fgc_flags |= FGC_SCHEMA_GIVEN; /* report that a schema is given */
 		namespaceId = LookupExplicitNamespace(schemaname, missing_schema_ok);
-		if (missing_schema_ok && !OidIsValid(namespaceId))
+		if (!OidIsValid(namespaceId))
 			return NULL;
+		*fgc_flags |= FGC_SCHEMA_EXISTS;	/* report that the schema exists */
 	}
 	else
 	{
@@ -1941,6 +2005,8 @@ OpernameGetCandidates(List *names, char oprkind, bool missing_schema_ok)
 		if (oprkind && operform->oprkind != oprkind)
 			continue;
 
+		*fgc_flags |= FGC_NAME_EXISTS;	/* the name is present in pg_operator */
+
 		if (OidIsValid(namespaceId))
 		{
 			/* Consider only opers in specified namespace */
@@ -2014,6 +2080,8 @@ OpernameGetCandidates(List *names, char oprkind, bool missing_schema_ok)
 			}
 		}
 
+		*fgc_flags |= FGC_NAME_VISIBLE; /* operator is in the right schema */
+
 		/*
 		 * Okay to add it to result list
 		 */

src/backend/catalog/pg_aggregate.c

@@ -836,6 +836,7 @@ lookup_agg_function(List *fnName,
 	Oid			vatype;
 	Oid		   *true_oid_array;
 	FuncDetailCode fdresult;
+	int			fgc_flags;
 	AclResult	aclresult;
 	int			i;
 
@@ -848,6 +849,7 @@ lookup_agg_function(List *fnName,
 	 */
 	fdresult = func_get_detail(fnName, NIL, NIL,
 							   nargs, input_types, false, false, false,
+							   &fgc_flags,
 							   &fnOid, rettype, &retset,
 							   &nvargs, &vatype,
 							   &true_oid_array, NULL);

src/backend/parser/parse_func.c

@@ -42,6 +42,8 @@ typedef enum
 	FUNCLOOKUP_AMBIGUOUS,
 } FuncLookupError;
 
+static int	func_lookup_failure_details(int fgc_flags, List *argnames,
+										bool proc_call);
 static void unify_hypothetical_args(ParseState *pstate,
 									List *fargs, int numAggregatedArgs,
 									Oid *actual_arg_types, Oid *declared_arg_types);
@@ -115,6 +117,7 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 	int			nvargs;
 	Oid			vatype;
 	FuncDetailCode fdresult;
+	int			fgc_flags;
 	char		aggkind = 0;
 	ParseCallbackState pcbstate;
 
@@ -266,6 +269,7 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 	fdresult = func_get_detail(funcname, fargs, argnames, nargs,
 							   actual_arg_types,
 							   !func_variadic, true, proc_call,
+							   &fgc_flags,
 							   &funcid, &rettype, &retset,
 							   &nvargs, &vatype,
 							   &declared_arg_types, &argdefaults);
@@ -563,8 +567,8 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 					 errmsg("procedure %s is not unique",
 							func_signature_string(funcname, nargs, argnames,
 												  actual_arg_types)),
-					 errhint("Could not choose a best candidate procedure. "
-							 "You might need to add explicit type casts."),
+					 errdetail("Could not choose a best candidate procedure."),
+					 errhint("You might need to add explicit type casts."),
 					 parser_errposition(pstate, location)));
 		else
 			ereport(ERROR,
@@ -572,8 +576,8 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 					 errmsg("function %s is not unique",
 							func_signature_string(funcname, nargs, argnames,
 												  actual_arg_types)),
-					 errhint("Could not choose a best candidate function. "
-							 "You might need to add explicit type casts."),
+					 errdetail("Could not choose a best candidate function."),
+					 errhint("You might need to add explicit type casts."),
 					 parser_errposition(pstate, location)));
 	}
 	else
@@ -601,7 +605,9 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 
 		/*
 		 * No function, and no column either.  Since we're dealing with
-		 * function notation, report "function does not exist".
+		 * function notation, report "function/procedure does not exist".
+		 * Depending on what was returned in fgc_flags, we can add some color
+		 * to that with detail or hint messages.
 		 */
 		if (list_length(agg_order) > 1 && !agg_within_group)
 		{
@@ -611,8 +617,8 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 					 errmsg("function %s does not exist",
 							func_signature_string(funcname, nargs, argnames,
 												  actual_arg_types)),
-					 errhint("No aggregate function matches the given name and argument types. "
-							 "Perhaps you misplaced ORDER BY; ORDER BY must appear "
+					 errdetail("No aggregate function matches the given name and argument types."),
+					 errhint("Perhaps you misplaced ORDER BY; ORDER BY must appear "
 							 "after all regular arguments of the aggregate."),
 					 parser_errposition(pstate, location)));
 		}
@@ -622,8 +628,8 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 					 errmsg("procedure %s does not exist",
 							func_signature_string(funcname, nargs, argnames,
 												  actual_arg_types)),
-					 errhint("No procedure matches the given name and argument types. "
-							 "You might need to add explicit type casts."),
+					 func_lookup_failure_details(fgc_flags, argnames,
+												 proc_call),
 					 parser_errposition(pstate, location)));
 		else
 			ereport(ERROR,
@@ -631,8 +637,8 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 					 errmsg("function %s does not exist",
 							func_signature_string(funcname, nargs, argnames,
 												  actual_arg_types)),
-					 errhint("No function matches the given name and argument types. "
-							 "You might need to add explicit type casts."),
+					 func_lookup_failure_details(fgc_flags, argnames,
+												 proc_call),
 					 parser_errposition(pstate, location)));
 	}
 
@@ -905,6 +911,104 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 	return retval;
 }
 
+/*
+ * Interpret the fgc_flags and issue a suitable detail or hint message.
+ *
+ * Helper function to reduce code duplication while throwing a
+ * function-not-found error.
+ */
+static int
+func_lookup_failure_details(int fgc_flags, List *argnames, bool proc_call)
+{
+	/*
+	 * If not FGC_NAME_VISIBLE, we shouldn't raise the question of whether the
+	 * arguments are wrong.  If the function name was not schema-qualified,
+	 * it's helpful to distinguish between doesn't-exist-anywhere and
+	 * not-in-search-path; but if it was, there's really nothing to add to the
+	 * basic "function/procedure %s does not exist" message.
+	 *
+	 * Note: we passed missing_ok = false to FuncnameGetCandidates, so there's
+	 * no need to consider FGC_SCHEMA_EXISTS here: we'd have already thrown an
+	 * error if an explicitly-given schema doesn't exist.
+	 */
+	if (!(fgc_flags & FGC_NAME_VISIBLE))
+	{
+		if (fgc_flags & FGC_SCHEMA_GIVEN)
+			return 0;			/* schema-qualified name */
+		else if (!(fgc_flags & FGC_NAME_EXISTS))
+		{
+			if (proc_call)
+				return errdetail("There is no procedure of that name.");
+			else
+				return errdetail("There is no function of that name.");
+		}
+		else
+		{
+			if (proc_call)
+				return errdetail("A procedure of that name exists, but it is not in the search_path.");
+			else
+				return errdetail("A function of that name exists, but it is not in the search_path.");
+		}
+	}
+
+	/*
+	 * Next, complain if nothing had the right number of arguments.  (This
+	 * takes precedence over wrong-argnames cases because we won't even look
+	 * at the argnames unless there's a workable number of arguments.)
+	 */
+	if (!(fgc_flags & FGC_ARGCOUNT_MATCH))
+	{
+		if (proc_call)
+			return errdetail("No procedure of that name accepts the given number of arguments.");
+		else
+			return errdetail("No function of that name accepts the given number of arguments.");
+	}
+
+	/*
+	 * If there are argnames, and we failed to match them, again we should
+	 * mention that and not bring up the argument types.
+	 */
+	if (argnames != NIL && !(fgc_flags & FGC_ARGNAMES_MATCH))
+	{
+		if (proc_call)
+			return errdetail("No procedure of that name accepts the given argument names.");
+		else
+			return errdetail("No function of that name accepts the given argument names.");
+	}
+
+	/*
+	 * We could have matched all the given argnames and still not have had a
+	 * valid call, either because of improper use of mixed notation, or
+	 * because of missing arguments, or because the user misused VARIADIC. The
+	 * rules about named-argument matching are finicky enough that it's worth
+	 * trying to be specific about the problem.  (The messages here are chosen
+	 * with full knowledge of the steps that namespace.c uses while checking a
+	 * potential match.)
+	 */
+	if (argnames != NIL && !(fgc_flags & FGC_ARGNAMES_NONDUP))
+		return errdetail("In the closest available match, "
+						 "an argument was specified both positionally and by name.");
+
+	if (argnames != NIL && !(fgc_flags & FGC_ARGNAMES_ALL))
+		return errdetail("In the closest available match, "
+						 "not all required arguments were supplied.");
+
+	if (argnames != NIL && !(fgc_flags & FGC_ARGNAMES_VALID))
+		return errhint("This call would be correct if the variadic array were labeled VARIADIC and placed last.");
+
+	if (fgc_flags & FGC_VARIADIC_FAIL)
+		return errhint("The VARIADIC parameter must be placed last, even when using argument names.");
+
+	/*
+	 * Otherwise, the problem must be incorrect argument types.
+	 */
+	if (proc_call)
+		(void) errdetail("No procedure of that name accepts the given argument types.");
+	else
+		(void) errdetail("No function of that name accepts the given argument types.");
+	return errhint("You might need to add explicit type casts.");
+}
+
 
 /* func_match_argtypes()
  *
@@ -1372,9 +1476,14 @@ func_select_candidate(int nargs,
  *	1) check for possible interpretation as a type coercion request
  *	2) apply the ambiguous-function resolution rules
  *
- * Return values *funcid through *true_typeids receive info about the function.
- * If argdefaults isn't NULL, *argdefaults receives a list of any default
- * argument expressions that need to be added to the given arguments.
+ * If there is no match at all, we return FUNCDETAIL_NOTFOUND, and *fgc_flags
+ * is filled with some flags that may be useful for issuing an on-point error
+ * message (see FuncnameGetCandidates).
+ *
+ * On success, return values *funcid through *true_typeids receive info about
+ * the function.  If argdefaults isn't NULL, *argdefaults receives a list of
+ * any default argument expressions that need to be added to the given
+ * arguments.
  *
  * When processing a named- or mixed-notation call (ie, fargnames isn't NIL),
  * the returned true_typeids and argdefaults are ordered according to the
@@ -1400,6 +1509,7 @@ func_get_detail(List *funcname,
 				bool expand_variadic,
 				bool expand_defaults,
 				bool include_out_arguments,
+				int *fgc_flags, /* return value */
 				Oid *funcid,	/* return value */
 				Oid *rettype,	/* return value */
 				bool *retset,	/* return value */
@@ -1424,7 +1534,8 @@ func_get_detail(List *funcname,
 	/* Get list of possible candidates from namespace search */
 	raw_candidates = FuncnameGetCandidates(funcname, nargs, fargnames,
 										   expand_variadic, expand_defaults,
-										   include_out_arguments, false);
+										   include_out_arguments, false,
+										   fgc_flags);
 
 	/*
 	 * Quickly check if there is an exact match to the input datatypes (there
@@ -1594,7 +1705,10 @@ func_get_detail(List *funcname,
 		 */
 		if (fargnames != NIL && !expand_variadic && nargs > 0 &&
 			best_candidate->argnumbers[nargs - 1] != nargs - 1)
+		{
+			*fgc_flags |= FGC_VARIADIC_FAIL;
 			return FUNCDETAIL_NOTFOUND;
+		}
 
 		*funcid = best_candidate->oid;
 		*nvargs = best_candidate->nvargs;
@@ -2053,6 +2167,7 @@ LookupFuncNameInternal(ObjectType objtype, List *funcname,
 {
 	Oid			result = InvalidOid;
 	FuncCandidateList clist;
+	int			fgc_flags;
 
 	/* NULL argtypes allowed for nullary functions only */
 	Assert(argtypes != NULL || nargs == 0);
@@ -2062,7 +2177,8 @@ LookupFuncNameInternal(ObjectType objtype, List *funcname,
 
 	/* Get list of candidate objects */
 	clist = FuncnameGetCandidates(funcname, nargs, NIL, false, false,
-								  include_out_arguments, missing_ok);
+								  include_out_arguments, missing_ok,
+								  &fgc_flags);
 
 	/* Scan list for a match to the arg types (if specified) and the objtype */
 	for (; clist != NULL; clist = clist->next)

src/backend/parser/parse_oper.c

@@ -72,7 +72,8 @@ static FuncDetailCode oper_select_candidate(int nargs,
 											Oid *operOid);
 static void op_error(ParseState *pstate, List *op,
 					 Oid arg1, Oid arg2,
-					 FuncDetailCode fdresult, int location);
+					 FuncDetailCode fdresult, int fgc_flags, int location);
+static int	oper_lookup_failure_details(int fgc_flags, bool is_unary_op);
 static bool make_oper_cache_key(ParseState *pstate, OprCacheKey *key,
 								List *opname, Oid ltypeId, Oid rtypeId,
 								int location);
@@ -373,6 +374,7 @@ oper(ParseState *pstate, List *opname, Oid ltypeId, Oid rtypeId,
 	Oid			operOid;
 	OprCacheKey key;
 	bool		key_ok;
+	int			fgc_flags = 0;
 	FuncDetailCode fdresult = FUNCDETAIL_NOTFOUND;
 	HeapTuple	tup = NULL;
 
@@ -404,7 +406,7 @@ oper(ParseState *pstate, List *opname, Oid ltypeId, Oid rtypeId,
 		FuncCandidateList clist;
 
 		/* Get binary operators of given name */
-		clist = OpernameGetCandidates(opname, 'b', false);
+		clist = OpernameGetCandidates(opname, 'b', false, &fgc_flags);
 
 		/* No operators found? Then fail... */
 		if (clist != NULL)
@@ -434,7 +436,8 @@ oper(ParseState *pstate, List *opname, Oid ltypeId, Oid rtypeId,
 			make_oper_cache_entry(&key, operOid);
 	}
 	else if (!noError)
-		op_error(pstate, opname, ltypeId, rtypeId, fdresult, location);
+		op_error(pstate, opname, ltypeId, rtypeId,
+				 fdresult, fgc_flags, location);
 
 	return (Operator) tup;
 }
@@ -520,6 +523,7 @@ left_oper(ParseState *pstate, List *op, Oid arg, bool noError, int location)
 	Oid			operOid;
 	OprCacheKey key;
 	bool		key_ok;
+	int			fgc_flags = 0;
 	FuncDetailCode fdresult = FUNCDETAIL_NOTFOUND;
 	HeapTuple	tup = NULL;
 
@@ -551,7 +555,7 @@ left_oper(ParseState *pstate, List *op, Oid arg, bool noError, int location)
 		FuncCandidateList clist;
 
 		/* Get prefix operators of given name */
-		clist = OpernameGetCandidates(op, 'l', false);
+		clist = OpernameGetCandidates(op, 'l', false, &fgc_flags);
 
 		/* No operators found? Then fail... */
 		if (clist != NULL)
@@ -585,7 +589,8 @@ left_oper(ParseState *pstate, List *op, Oid arg, bool noError, int location)
 			make_oper_cache_entry(&key, operOid);
 	}
 	else if (!noError)
-		op_error(pstate, op, InvalidOid, arg, fdresult, location);
+		op_error(pstate, op, InvalidOid, arg,
+				 fdresult, fgc_flags, location);
 
 	return (Operator) tup;
 }
@@ -621,29 +626,67 @@ op_signature_string(List *op, Oid arg1, Oid arg2)
 static void
 op_error(ParseState *pstate, List *op,
 		 Oid arg1, Oid arg2,
-		 FuncDetailCode fdresult, int location)
+		 FuncDetailCode fdresult, int fgc_flags, int location)
 {
 	if (fdresult == FUNCDETAIL_MULTIPLE)
 		ereport(ERROR,
 				(errcode(ERRCODE_AMBIGUOUS_FUNCTION),
 				 errmsg("operator is not unique: %s",
 						op_signature_string(op, arg1, arg2)),
-				 errhint("Could not choose a best candidate operator. "
-						 "You might need to add explicit type casts."),
+				 errdetail("Could not choose a best candidate operator."),
+				 errhint("You might need to add explicit type casts."),
 				 parser_errposition(pstate, location)));
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_UNDEFINED_FUNCTION),
 				 errmsg("operator does not exist: %s",
 						op_signature_string(op, arg1, arg2)),
-				 (!arg1 || !arg2) ?
-				 errhint("No operator matches the given name and argument type. "
-						 "You might need to add an explicit type cast.") :
-				 errhint("No operator matches the given name and argument types. "
-						 "You might need to add explicit type casts."),
+				 oper_lookup_failure_details(fgc_flags, (!arg1 || !arg2)),
 				 parser_errposition(pstate, location)));
 }
 
+/*
+ * Interpret the fgc_flags and issue a suitable detail or hint message.
+ */
+static int
+oper_lookup_failure_details(int fgc_flags, bool is_unary_op)
+{
+	/*
+	 * If not FGC_NAME_VISIBLE, we shouldn't raise the question of whether the
+	 * arguments are wrong.  If the operator name was not schema-qualified,
+	 * it's helpful to distinguish between doesn't-exist-anywhere and
+	 * not-in-search-path; but if it was, there's really nothing to add to the
+	 * basic "operator does not exist" message.
+	 *
+	 * Note: we passed missing_ok = false to OpernameGetCandidates, so there's
+	 * no need to consider FGC_SCHEMA_EXISTS here: we'd have already thrown an
+	 * error if an explicitly-given schema doesn't exist.
+	 */
+	if (!(fgc_flags & FGC_NAME_VISIBLE))
+	{
+		if (fgc_flags & FGC_SCHEMA_GIVEN)
+			return 0;			/* schema-qualified name */
+		else if (!(fgc_flags & FGC_NAME_EXISTS))
+			return errdetail("There is no operator of that name.");
+		else
+			return errdetail("An operator of that name exists, but it is not in the search_path.");
+	}
+
+	/*
+	 * Otherwise, the problem must be incorrect argument type(s).
+	 */
+	if (is_unary_op)
+	{
+		(void) errdetail("No operator of that name accepts the given argument type.");
+		return errhint("You might need to add an explicit type cast.");
+	}
+	else
+	{
+		(void) errdetail("No operator of that name accepts the given argument types.");
+		return errhint("You might need to add explicit type casts.");
+	}
+}
+
 /*
  * make_op()
  *		Operator expression construction.

src/backend/utils/adt/regproc.c

@@ -71,6 +71,7 @@ regprocin(PG_FUNCTION_ARGS)
 	RegProcedure result;
 	List	   *names;
 	FuncCandidateList clist;
+	int			fgc_flags;
 
 	/* Handle "-" or numeric OID */
 	if (parseDashOrOid(pro_name_or_oid, &result, escontext))
@@ -93,7 +94,8 @@ regprocin(PG_FUNCTION_ARGS)
 	if (names == NIL)
 		PG_RETURN_NULL();
 
-	clist = FuncnameGetCandidates(names, -1, NIL, false, false, false, true);
+	clist = FuncnameGetCandidates(names, -1, NIL, false, false, false, true,
+								  &fgc_flags);
 
 	if (clist == NULL)
 		ereturn(escontext, (Datum) 0,
@@ -164,13 +166,15 @@ regprocout(PG_FUNCTION_ARGS)
 		{
 			char	   *nspname;
 			FuncCandidateList clist;
+			int			fgc_flags;
 
 			/*
 			 * Would this proc be found (uniquely!) by regprocin? If not,
 			 * qualify it.
 			 */
 			clist = FuncnameGetCandidates(list_make1(makeString(proname)),
-										  -1, NIL, false, false, false, false);
+										  -1, NIL, false, false, false, false,
+										  &fgc_flags);
 			if (clist != NULL && clist->next == NULL &&
 				clist->oid == proid)
 				nspname = NULL;
@@ -231,6 +235,7 @@ regprocedurein(PG_FUNCTION_ARGS)
 	int			nargs;
 	Oid			argtypes[FUNC_MAX_ARGS];
 	FuncCandidateList clist;
+	int			fgc_flags;
 
 	/* Handle "-" or numeric OID */
 	if (parseDashOrOid(pro_name_or_oid, &result, escontext))
@@ -251,8 +256,8 @@ regprocedurein(PG_FUNCTION_ARGS)
 							  escontext))
 		PG_RETURN_NULL();
 
-	clist = FuncnameGetCandidates(names, nargs, NIL, false, false,
-								  false, true);
+	clist = FuncnameGetCandidates(names, nargs, NIL, false, false, false, true,
+								  &fgc_flags);
 
 	for (; clist; clist = clist->next)
 	{
@@ -483,6 +488,7 @@ regoperin(PG_FUNCTION_ARGS)
 	Oid			result;
 	List	   *names;
 	FuncCandidateList clist;
+	int			fgc_flags;
 
 	/* Handle "0" or numeric OID */
 	if (parseNumericOid(opr_name_or_oid, &result, escontext))
@@ -502,7 +508,7 @@ regoperin(PG_FUNCTION_ARGS)
 	if (names == NIL)
 		PG_RETURN_NULL();
 
-	clist = OpernameGetCandidates(names, '\0', true);
+	clist = OpernameGetCandidates(names, '\0', true, &fgc_flags);
 
 	if (clist == NULL)
 		ereturn(escontext, (Datum) 0,
@@ -572,13 +578,14 @@ regoperout(PG_FUNCTION_ARGS)
 		else
 		{
 			FuncCandidateList clist;
+			int			fgc_flags;
 
 			/*
 			 * Would this oper be found (uniquely!) by regoperin? If not,
 			 * qualify it.
 			 */
 			clist = OpernameGetCandidates(list_make1(makeString(oprname)),
-										  '\0', false);
+										  '\0', false, &fgc_flags);
 			if (clist != NULL && clist->next == NULL &&
 				clist->oid == oprid)
 				result = pstrdup(oprname);

src/backend/utils/adt/ruleutils.c

@@ -13265,6 +13265,7 @@ generate_function_name(Oid funcid, int nargs, List *argnames, Oid *argtypes,
 	bool		use_variadic;
 	char	   *nspname;
 	FuncDetailCode p_result;
+	int			fgc_flags;
 	Oid			p_funcid;
 	Oid			p_rettype;
 	bool		p_retset;
@@ -13323,6 +13324,7 @@ generate_function_name(Oid funcid, int nargs, List *argnames, Oid *argtypes,
 		p_result = func_get_detail(list_make1(makeString(proname)),
 								   NIL, argnames, nargs, argtypes,
 								   !use_variadic, true, false,
+								   &fgc_flags,
 								   &p_funcid, &p_rettype,
 								   &p_retset, &p_nvargs, &p_vatype,
 								   &p_true_typeids, NULL);

src/include/catalog/namespace.h

@@ -39,6 +39,24 @@ typedef struct _FuncCandidateList
 	Oid			args[FLEXIBLE_ARRAY_MEMBER];	/* arg types */
 }		   *FuncCandidateList;
 
+/*
+ * FuncnameGetCandidates also returns a bitmask containing these flags,
+ * which report on what it found or didn't find.  They can help callers
+ * produce better error reports after a function lookup failure.
+ */
+#define FGC_SCHEMA_GIVEN	0x0001	/* Func name includes a schema */
+#define FGC_SCHEMA_EXISTS	0x0002	/* Found the explicitly-specified schema */
+#define FGC_NAME_EXISTS		0x0004	/* Found a routine by that name */
+#define FGC_NAME_VISIBLE	0x0008	/* Found a routine name/schema match */
+#define FGC_ARGCOUNT_MATCH	0x0010	/* Found a func with right # of args */
+/* These bits relate only to calls using named or mixed arguments: */
+#define FGC_ARGNAMES_MATCH	0x0020	/* Found a func matching all argnames */
+#define FGC_ARGNAMES_NONDUP	0x0040	/* argnames don't overlap positional args */
+#define FGC_ARGNAMES_ALL	0x0080	/* Found a func with no missing args */
+#define FGC_ARGNAMES_VALID	0x0100	/* Found a fully-valid use of argnames */
+/* These bits are actually filled by func_get_detail: */
+#define FGC_VARIADIC_FAIL	0x0200	/* Disallowed VARIADIC with named args */
+
 /*
  * Result of checkTempNamespaceStatus
  */
@@ -102,12 +120,14 @@ extern FuncCandidateList FuncnameGetCandidates(List *names,
 											   bool expand_variadic,
 											   bool expand_defaults,
 											   bool include_out_arguments,
-											   bool missing_ok);
+											   bool missing_ok,
+											   int *fgc_flags);
 extern bool FunctionIsVisible(Oid funcid);
 
 extern Oid	OpernameGetOprid(List *names, Oid oprleft, Oid oprright);
 extern FuncCandidateList OpernameGetCandidates(List *names, char oprkind,
-											   bool missing_schema_ok);
+											   bool missing_schema_ok,
+											   int *fgc_flags);
 extern bool OperatorIsVisible(Oid oprid);
 
 extern Oid	OpclassnameGetOpcid(Oid amid, const char *opcname);

src/include/parser/parse_func.h

@@ -40,6 +40,7 @@ extern FuncDetailCode func_get_detail(List *funcname,
 									  int nargs, Oid *argtypes,
 									  bool expand_variadic, bool expand_defaults,
 									  bool include_out_arguments,
+									  int *fgc_flags,
 									  Oid *funcid, Oid *rettype,
 									  bool *retset, int *nvargs, Oid *vatype,
 									  Oid **true_typeids, List **argdefaults);

src/pl/plperl/expected/plperl_elog.out

@@ -41,7 +41,7 @@ select uses_global();
 ERROR:  function uses_global() does not exist
 LINE 1: select uses_global();
                ^
-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.
 SET plperl.use_strict = false;
 create or replace function uses_global() returns text language plperl as $$
 

src/pl/plperl/expected/plperl_elog_1.out

@@ -41,7 +41,7 @@ select uses_global();
 ERROR:  function uses_global() does not exist
 LINE 1: select uses_global();
                ^
-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.
 SET plperl.use_strict = false;
 create or replace function uses_global() returns text language plperl as $$
 

src/pl/plpgsql/src/expected/plpgsql_call.out

@@ -440,7 +440,8 @@ $$;
 ERROR:  procedure test_proc12(integer, integer, text[]) does not exist
 LINE 1: CALL test_proc12(_a, _b, _c)
              ^
-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.
 QUERY:  CALL test_proc12(_a, _b, _c)
 CONTEXT:  PL/pgSQL function inline_code_block line 5 at CALL
 -- transition variable assignment

src/pl/plpgsql/src/expected/plpgsql_record.out

@@ -466,7 +466,8 @@ select getf1(1);
 ERROR:  function getf1(integer) does not exist
 LINE 1: select getf1(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.
 select getf1(row(1,2));
  getf1 
 -------

src/pl/plpython/expected/plpython_error.out

@@ -63,7 +63,7 @@ SELECT exception_index_invalid_nested();
 ERROR:  spiexceptions.UndefinedFunction: function test5(unknown) does not exist
 LINE 1: SELECT test5('foo')
                ^
-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.
 QUERY:  SELECT test5('foo')
 CONTEXT:  Traceback (most recent call last):
   PL/Python function "exception_index_invalid_nested", line 1, in <module>

src/test/modules/libpq_pipeline/traces/pipeline_abort.trace

@@ -27,7 +27,7 @@ B	4	ParseComplete
 B	4	BindComplete
 B	4	NoData
 B	15	CommandComplete	 "INSERT 0 1"
-B	NN	ErrorResponse	 S "ERROR" V "ERROR" C "42883" M "function no_such_function(integer) does not exist" H "No function matches the given name and argument types. You might need to add explicit type casts." P "8" F "SSSS" L "SSSS" R "SSSS" \x00
+B	NN	ErrorResponse	 S "ERROR" V "ERROR" C "42883" M "function no_such_function(integer) does not exist" D "There is no function of that name." P "8" F "SSSS" L "SSSS" R "SSSS" \x00
 B	5	ReadyForQuery	 I
 B	4	ParseComplete
 B	4	BindComplete

src/test/modules/test_extensions/expected/test_extensions.out

@@ -333,7 +333,7 @@ SELECT ext_cor_func();
 ERROR:  function ext_cor_func() does not exist
 LINE 1: SELECT ext_cor_func();
                ^
-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 * FROM ext_cor_view;
           col           
 ------------------------
@@ -649,7 +649,6 @@ SELECT dep_req3b();  -- fails
 ERROR:  function public.dep_req2() does not exist
 LINE 1:  SELECT public.dep_req2() || ' req3b' 
                 ^
-HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
 QUERY:   SELECT public.dep_req2() || ' req3b' 
 CONTEXT:  SQL function "dep_req3b" statement 1
 DROP EXTENSION test_ext_req_schema3;

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

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]]);

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 
 --------------

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

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

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 $$ SELECT b - c $$;

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? 
 ----------

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

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
 --

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?    

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
 --

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()
 --

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)

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)

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)

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)

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;

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

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

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
  */

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
 --

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
 --

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

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? 

src/test/regress/sql/create_operator.sql

@@ -22,6 +22,13 @@ CREATE OPERATOR #%# (
 -- Test operator created above
 SELECT @#@ 24;
 
+-- Test error cases
+select @@##@@ 24;  -- no such operator
+set search_path = pg_catalog;
+select @#@ 24;  -- wrong schema
+reset search_path;
+select @#@ 24.0;  -- wrong data type
+
 -- Test comments
 COMMENT ON OPERATOR ###### (NONE, int4) IS 'bad prefix';
 COMMENT ON OPERATOR ###### (int4, NONE) IS 'bad postfix';

src/test/regress/sql/polymorphism.sql

@@ -873,6 +873,26 @@ select * from dfunc(1,c := 2,d := 3); -- fail, no value for b
 
 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]);
+select xleast(1, variadic arr => array[2,3]);
+
+set search_path = pg_catalog;
+select xleast(1, variadic arr => array[2,3]);  -- wrong schema
+reset search_path;
+select xleast(foo => 1, variadic arr => array[2,3]);  -- wrong argument name
+select xleast(x => 1, variadic array[2,3]);  -- misuse of mixed notation
+select xleast(1, variadic x => array[2,3]);  -- misuse of mixed notation
+select xleast(arr => array[1], variadic x => 3);  -- wrong arg is VARIADIC
+select xleast(arr => array[1], x => 3);  -- failed to use VARIADIC
+select xleast(arr => 1, variadic x => array[2,3]);  -- mixed-up args
+
+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 $$