Adding upstream version 14.5.upstream/14.5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3346 insertions, 0 deletions

diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c
new file mode 100644
index 0000000..fc9224c
--- /dev/null
+++ b/src/backend/parser/parse_coerce.c
@@ -0,0 +1,3346 @@
+/*-------------------------------------------------------------------------
+ *
+ * parse_coerce.c
+ *		handle type coercions/conversions for parser
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/parser/parse_coerce.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "catalog/pg_cast.h"
+#include "catalog/pg_class.h"
+#include "catalog/pg_inherits.h"
+#include "catalog/pg_proc.h"
+#include "catalog/pg_type.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
+#include "parser/parse_coerce.h"
+#include "parser/parse_relation.h"
+#include "parser/parse_type.h"
+#include "utils/builtins.h"
+#include "utils/datum.h"		/* needed for datumIsEqual() */
+#include "utils/fmgroids.h"
+#include "utils/lsyscache.h"
+#include "utils/syscache.h"
+#include "utils/typcache.h"
+
+
+static Node *coerce_type_typmod(Node *node,
+								Oid targetTypeId, int32 targetTypMod,
+								CoercionContext ccontext, CoercionForm cformat,
+								int location,
+								bool hideInputCoercion);
+static void hide_coercion_node(Node *node);
+static Node *build_coercion_expression(Node *node,
+									   CoercionPathType pathtype,
+									   Oid funcId,
+									   Oid targetTypeId, int32 targetTypMod,
+									   CoercionContext ccontext, CoercionForm cformat,
+									   int location);
+static Node *coerce_record_to_complex(ParseState *pstate, Node *node,
+									  Oid targetTypeId,
+									  CoercionContext ccontext,
+									  CoercionForm cformat,
+									  int location);
+static bool is_complex_array(Oid typid);
+static bool typeIsOfTypedTable(Oid reltypeId, Oid reloftypeId);
+
+
+/*
+ * coerce_to_target_type()
+ *		Convert an expression to a target type and typmod.
+ *
+ * This is the general-purpose entry point for arbitrary type coercion
+ * operations.  Direct use of the component operations can_coerce_type,
+ * coerce_type, and coerce_type_typmod should be restricted to special
+ * cases (eg, when the conversion is expected to succeed).
+ *
+ * Returns the possibly-transformed expression tree, or NULL if the type
+ * conversion is not possible.  (We do this, rather than ereport'ing directly,
+ * so that callers can generate custom error messages indicating context.)
+ *
+ * pstate - parse state (can be NULL, see coerce_type)
+ * expr - input expression tree (already transformed by transformExpr)
+ * exprtype - result type of expr
+ * targettype - desired result type
+ * targettypmod - desired result typmod
+ * ccontext, cformat - context indicators to control coercions
+ * location - parse location of the coercion request, or -1 if unknown/implicit
+ */
+Node *
+coerce_to_target_type(ParseState *pstate, Node *expr, Oid exprtype,
+					  Oid targettype, int32 targettypmod,
+					  CoercionContext ccontext,
+					  CoercionForm cformat,
+					  int location)
+{
+	Node	   *result;
+	Node	   *origexpr;
+
+	if (!can_coerce_type(1, &exprtype, &targettype, ccontext))
+		return NULL;
+
+	/*
+	 * If the input has a CollateExpr at the top, strip it off, perform the
+	 * coercion, and put a new one back on.  This is annoying since it
+	 * duplicates logic in coerce_type, but if we don't do this then it's too
+	 * hard to tell whether coerce_type actually changed anything, and we
+	 * *must* know that to avoid possibly calling hide_coercion_node on
+	 * something that wasn't generated by coerce_type.  Note that if there are
+	 * multiple stacked CollateExprs, we just discard all but the topmost.
+	 * Also, if the target type isn't collatable, we discard the CollateExpr.
+	 */
+	origexpr = expr;
+	while (expr && IsA(expr, CollateExpr))
+		expr = (Node *) ((CollateExpr *) expr)->arg;
+
+	result = coerce_type(pstate, expr, exprtype,
+						 targettype, targettypmod,
+						 ccontext, cformat, location);
+
+	/*
+	 * If the target is a fixed-length type, it may need a length coercion as
+	 * well as a type coercion.  If we find ourselves adding both, force the
+	 * inner coercion node to implicit display form.
+	 */
+	result = coerce_type_typmod(result,
+								targettype, targettypmod,
+								ccontext, cformat, location,
+								(result != expr && !IsA(result, Const)));
+
+	if (expr != origexpr && type_is_collatable(targettype))
+	{
+		/* Reinstall top CollateExpr */
+		CollateExpr *coll = (CollateExpr *) origexpr;
+		CollateExpr *newcoll = makeNode(CollateExpr);
+
+		newcoll->arg = (Expr *) result;
+		newcoll->collOid = coll->collOid;
+		newcoll->location = coll->location;
+		result = (Node *) newcoll;
+	}
+
+	return result;
+}
+
+
+/*
+ * coerce_type()
+ *		Convert an expression to a different type.
+ *
+ * The caller should already have determined that the coercion is possible;
+ * see can_coerce_type.
+ *
+ * Normally, no coercion to a typmod (length) is performed here.  The caller
+ * must call coerce_type_typmod as well, if a typmod constraint is wanted.
+ * (But if the target type is a domain, it may internally contain a
+ * typmod constraint, which will be applied inside coerce_to_domain.)
+ * In some cases pg_cast specifies a type coercion function that also
+ * applies length conversion, and in those cases only, the result will
+ * already be properly coerced to the specified typmod.
+ *
+ * pstate is only used in the case that we are able to resolve the type of
+ * a previously UNKNOWN Param.  It is okay to pass pstate = NULL if the
+ * caller does not want type information updated for Params.
+ *
+ * Note: this function must not modify the given expression tree, only add
+ * decoration on top of it.  See transformSetOperationTree, for example.
+ */
+Node *
+coerce_type(ParseState *pstate, Node *node,
+			Oid inputTypeId, Oid targetTypeId, int32 targetTypeMod,
+			CoercionContext ccontext, CoercionForm cformat, int location)
+{
+	Node	   *result;
+	CoercionPathType pathtype;
+	Oid			funcId;
+
+	if (targetTypeId == inputTypeId ||
+		node == NULL)
+	{
+		/* no conversion needed */
+		return node;
+	}
+	if (targetTypeId == ANYOID ||
+		targetTypeId == ANYELEMENTOID ||
+		targetTypeId == ANYNONARRAYOID ||
+		targetTypeId == ANYCOMPATIBLEOID ||
+		targetTypeId == ANYCOMPATIBLENONARRAYOID)
+	{
+		/*
+		 * Assume can_coerce_type verified that implicit coercion is okay.
+		 *
+		 * Note: by returning the unmodified node here, we are saying that
+		 * it's OK to treat an UNKNOWN constant as a valid input for a
+		 * function accepting one of these pseudotypes.  This should be all
+		 * right, since an UNKNOWN value is still a perfectly valid Datum.
+		 *
+		 * NB: we do NOT want a RelabelType here: the exposed type of the
+		 * function argument must be its actual type, not the polymorphic
+		 * pseudotype.
+		 */
+		return node;
+	}
+	if (targetTypeId == ANYARRAYOID ||
+		targetTypeId == ANYENUMOID ||
+		targetTypeId == ANYRANGEOID ||
+		targetTypeId == ANYMULTIRANGEOID ||
+		targetTypeId == ANYCOMPATIBLEARRAYOID ||
+		targetTypeId == ANYCOMPATIBLERANGEOID ||
+		targetTypeId == ANYCOMPATIBLEMULTIRANGEOID)
+	{
+		/*
+		 * Assume can_coerce_type verified that implicit coercion is okay.
+		 *
+		 * These cases are unlike the ones above because the exposed type of
+		 * the argument must be an actual array, enum, range, or multirange
+		 * type.  In particular the argument must *not* be an UNKNOWN
+		 * constant.  If it is, we just fall through; below, we'll call the
+		 * pseudotype's input function, which will produce an error.  Also, if
+		 * what we have is a domain over array, enum, range, or multirange, we
+		 * have to relabel it to its base type.
+		 *
+		 * Note: currently, we can't actually see a domain-over-enum here,
+		 * since the other functions in this file will not match such a
+		 * parameter to ANYENUM.  But that should get changed eventually.
+		 */
+		if (inputTypeId != UNKNOWNOID)
+		{
+			Oid			baseTypeId = getBaseType(inputTypeId);
+
+			if (baseTypeId != inputTypeId)
+			{
+				RelabelType *r = makeRelabelType((Expr *) node,
+												 baseTypeId, -1,
+												 InvalidOid,
+												 cformat);
+
+				r->location = location;
+				return (Node *) r;
+			}
+			/* Not a domain type, so return it as-is */
+			return node;
+		}
+	}
+	if (inputTypeId == UNKNOWNOID && IsA(node, Const))
+	{
+		/*
+		 * Input is a string constant with previously undetermined type. Apply
+		 * the target type's typinput function to it to produce a constant of
+		 * the target type.
+		 *
+		 * NOTE: this case cannot be folded together with the other
+		 * constant-input case, since the typinput function does not
+		 * necessarily behave the same as a type conversion function. For
+		 * example, int4's typinput function will reject "1.2", whereas
+		 * float-to-int type conversion will round to integer.
+		 *
+		 * XXX if the typinput function is not immutable, we really ought to
+		 * postpone evaluation of the function call until runtime. But there
+		 * is no way to represent a typinput function call as an expression
+		 * tree, because C-string values are not Datums. (XXX This *is*
+		 * possible as of 7.3, do we want to do it?)
+		 */
+		Const	   *con = (Const *) node;
+		Const	   *newcon = makeNode(Const);
+		Oid			baseTypeId;
+		int32		baseTypeMod;
+		int32		inputTypeMod;
+		Type		baseType;
+		ParseCallbackState pcbstate;
+
+		/*
+		 * If the target type is a domain, we want to call its base type's
+		 * input routine, not domain_in().  This is to avoid premature failure
+		 * when the domain applies a typmod: existing input routines follow
+		 * implicit-coercion semantics for length checks, which is not always
+		 * what we want here.  The needed check will be applied properly
+		 * inside coerce_to_domain().
+		 */
+		baseTypeMod = targetTypeMod;
+		baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
+
+		/*
+		 * For most types we pass typmod -1 to the input routine, because
+		 * existing input routines follow implicit-coercion semantics for
+		 * length checks, which is not always what we want here.  Any length
+		 * constraint will be applied later by our caller.  An exception
+		 * however is the INTERVAL type, for which we *must* pass the typmod
+		 * or it won't be able to obey the bizarre SQL-spec input rules. (Ugly
+		 * as sin, but so is this part of the spec...)
+		 */
+		if (baseTypeId == INTERVALOID)
+			inputTypeMod = baseTypeMod;
+		else
+			inputTypeMod = -1;
+
+		baseType = typeidType(baseTypeId);
+
+		newcon->consttype = baseTypeId;
+		newcon->consttypmod = inputTypeMod;
+		newcon->constcollid = typeTypeCollation(baseType);
+		newcon->constlen = typeLen(baseType);
+		newcon->constbyval = typeByVal(baseType);
+		newcon->constisnull = con->constisnull;
+
+		/*
+		 * We use the original literal's location regardless of the position
+		 * of the coercion.  This is a change from pre-9.2 behavior, meant to
+		 * simplify life for pg_stat_statements.
+		 */
+		newcon->location = con->location;
+
+		/*
+		 * Set up to point at the constant's text if the input routine throws
+		 * an error.
+		 */
+		setup_parser_errposition_callback(&pcbstate, pstate, con->location);
+
+		/*
+		 * We assume here that UNKNOWN's internal representation is the same
+		 * as CSTRING.
+		 */
+		if (!con->constisnull)
+			newcon->constvalue = stringTypeDatum(baseType,
+												 DatumGetCString(con->constvalue),
+												 inputTypeMod);
+		else
+			newcon->constvalue = stringTypeDatum(baseType,
+												 NULL,
+												 inputTypeMod);
+
+		/*
+		 * If it's a varlena value, force it to be in non-expanded
+		 * (non-toasted) format; this avoids any possible dependency on
+		 * external values and improves consistency of representation.
+		 */
+		if (!con->constisnull && newcon->constlen == -1)
+			newcon->constvalue =
+				PointerGetDatum(PG_DETOAST_DATUM(newcon->constvalue));
+
+#ifdef RANDOMIZE_ALLOCATED_MEMORY
+
+		/*
+		 * For pass-by-reference data types, repeat the conversion to see if
+		 * the input function leaves any uninitialized bytes in the result. We
+		 * can only detect that reliably if RANDOMIZE_ALLOCATED_MEMORY is
+		 * enabled, so we don't bother testing otherwise.  The reason we don't
+		 * want any instability in the input function is that comparison of
+		 * Const nodes relies on bytewise comparison of the datums, so if the
+		 * input function leaves garbage then subexpressions that should be
+		 * identical may not get recognized as such.  See pgsql-hackers
+		 * discussion of 2008-04-04.
+		 */
+		if (!con->constisnull && !newcon->constbyval)
+		{
+			Datum		val2;
+
+			val2 = stringTypeDatum(baseType,
+								   DatumGetCString(con->constvalue),
+								   inputTypeMod);
+			if (newcon->constlen == -1)
+				val2 = PointerGetDatum(PG_DETOAST_DATUM(val2));
+			if (!datumIsEqual(newcon->constvalue, val2, false, newcon->constlen))
+				elog(WARNING, "type %s has unstable input conversion for \"%s\"",
+					 typeTypeName(baseType), DatumGetCString(con->constvalue));
+		}
+#endif
+
+		cancel_parser_errposition_callback(&pcbstate);
+
+		result = (Node *) newcon;
+
+		/* If target is a domain, apply constraints. */
+		if (baseTypeId != targetTypeId)
+			result = coerce_to_domain(result,
+									  baseTypeId, baseTypeMod,
+									  targetTypeId,
+									  ccontext, cformat, location,
+									  false);
+
+		ReleaseSysCache(baseType);
+
+		return result;
+	}
+	if (IsA(node, Param) &&
+		pstate != NULL && pstate->p_coerce_param_hook != NULL)
+	{
+		/*
+		 * Allow the CoerceParamHook to decide what happens.  It can return a
+		 * transformed node (very possibly the same Param node), or return
+		 * NULL to indicate we should proceed with normal coercion.
+		 */
+		result = pstate->p_coerce_param_hook(pstate,
+											 (Param *) node,
+											 targetTypeId,
+											 targetTypeMod,
+											 location);
+		if (result)
+			return result;
+	}
+	if (IsA(node, CollateExpr))
+	{
+		/*
+		 * If we have a COLLATE clause, we have to push the coercion
+		 * underneath the COLLATE; or discard the COLLATE if the target type
+		 * isn't collatable.  This is really ugly, but there is little choice
+		 * because the above hacks on Consts and Params wouldn't happen
+		 * otherwise.  This kluge has consequences in coerce_to_target_type.
+		 */
+		CollateExpr *coll = (CollateExpr *) node;
+
+		result = coerce_type(pstate, (Node *) coll->arg,
+							 inputTypeId, targetTypeId, targetTypeMod,
+							 ccontext, cformat, location);
+		if (type_is_collatable(targetTypeId))
+		{
+			CollateExpr *newcoll = makeNode(CollateExpr);
+
+			newcoll->arg = (Expr *) result;
+			newcoll->collOid = coll->collOid;
+			newcoll->location = coll->location;
+			result = (Node *) newcoll;
+		}
+		return result;
+	}
+	pathtype = find_coercion_pathway(targetTypeId, inputTypeId, ccontext,
+									 &funcId);
+	if (pathtype != COERCION_PATH_NONE)
+	{
+		if (pathtype != COERCION_PATH_RELABELTYPE)
+		{
+			/*
+			 * Generate an expression tree representing run-time application
+			 * of the conversion function.  If we are dealing with a domain
+			 * target type, the conversion function will yield the base type,
+			 * and we need to extract the correct typmod to use from the
+			 * domain's typtypmod.
+			 */
+			Oid			baseTypeId;
+			int32		baseTypeMod;
+
+			baseTypeMod = targetTypeMod;
+			baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
+
+			result = build_coercion_expression(node, pathtype, funcId,
+											   baseTypeId, baseTypeMod,
+											   ccontext, cformat, location);
+
+			/*
+			 * If domain, coerce to the domain type and relabel with domain
+			 * type ID, hiding the previous coercion node.
+			 */
+			if (targetTypeId != baseTypeId)
+				result = coerce_to_domain(result, baseTypeId, baseTypeMod,
+										  targetTypeId,
+										  ccontext, cformat, location,
+										  true);
+		}
+		else
+		{
+			/*
+			 * We don't need to do a physical conversion, but we do need to
+			 * attach a RelabelType node so that the expression will be seen
+			 * to have the intended type when inspected by higher-level code.
+			 *
+			 * Also, domains may have value restrictions beyond the base type
+			 * that must be accounted for.  If the destination is a domain
+			 * then we won't need a RelabelType node.
+			 */
+			result = coerce_to_domain(node, InvalidOid, -1, targetTypeId,
+									  ccontext, cformat, location,
+									  false);
+			if (result == node)
+			{
+				/*
+				 * XXX could we label result with exprTypmod(node) instead of
+				 * default -1 typmod, to save a possible length-coercion
+				 * later? Would work if both types have same interpretation of
+				 * typmod, which is likely but not certain.
+				 */
+				RelabelType *r = makeRelabelType((Expr *) result,
+												 targetTypeId, -1,
+												 InvalidOid,
+												 cformat);
+
+				r->location = location;
+				result = (Node *) r;
+			}
+		}
+		return result;
+	}
+	if (inputTypeId == RECORDOID &&
+		ISCOMPLEX(targetTypeId))
+	{
+		/* Coerce a RECORD to a specific complex type */
+		return coerce_record_to_complex(pstate, node, targetTypeId,
+										ccontext, cformat, location);
+	}
+	if (targetTypeId == RECORDOID &&
+		ISCOMPLEX(inputTypeId))
+	{
+		/* Coerce a specific complex type to RECORD */
+		/* NB: we do NOT want a RelabelType here */
+		return node;
+	}
+#ifdef NOT_USED
+	if (inputTypeId == RECORDARRAYOID &&
+		is_complex_array(targetTypeId))
+	{
+		/* Coerce record[] to a specific complex array type */
+		/* not implemented yet ... */
+	}
+#endif
+	if (targetTypeId == RECORDARRAYOID &&
+		is_complex_array(inputTypeId))
+	{
+		/* Coerce a specific complex array type to record[] */
+		/* NB: we do NOT want a RelabelType here */
+		return node;
+	}
+	if (typeInheritsFrom(inputTypeId, targetTypeId)
+		|| typeIsOfTypedTable(inputTypeId, targetTypeId))
+	{
+		/*
+		 * Input class type is a subclass of target, so generate an
+		 * appropriate runtime conversion (removing unneeded columns and
+		 * possibly rearranging the ones that are wanted).
+		 *
+		 * We will also get here when the input is a domain over a subclass of
+		 * the target type.  To keep life simple for the executor, we define
+		 * ConvertRowtypeExpr as only working between regular composite types;
+		 * therefore, in such cases insert a RelabelType to smash the input
+		 * expression down to its base type.
+		 */
+		Oid			baseTypeId = getBaseType(inputTypeId);
+		ConvertRowtypeExpr *r = makeNode(ConvertRowtypeExpr);
+
+		if (baseTypeId != inputTypeId)
+		{
+			RelabelType *rt = makeRelabelType((Expr *) node,
+											  baseTypeId, -1,
+											  InvalidOid,
+											  COERCE_IMPLICIT_CAST);
+
+			rt->location = location;
+			node = (Node *) rt;
+		}
+		r->arg = (Expr *) node;
+		r->resulttype = targetTypeId;
+		r->convertformat = cformat;
+		r->location = location;
+		return (Node *) r;
+	}
+	/* If we get here, caller blew it */
+	elog(ERROR, "failed to find conversion function from %s to %s",
+		 format_type_be(inputTypeId), format_type_be(targetTypeId));
+	return NULL;				/* keep compiler quiet */
+}
+
+
+/*
+ * can_coerce_type()
+ *		Can input_typeids be coerced to target_typeids?
+ *
+ * We must be told the context (CAST construct, assignment, implicit coercion)
+ * as this determines the set of available casts.
+ */
+bool
+can_coerce_type(int nargs, const Oid *input_typeids, const Oid *target_typeids,
+				CoercionContext ccontext)
+{
+	bool		have_generics = false;
+	int			i;
+
+	/* run through argument list... */
+	for (i = 0; i < nargs; i++)
+	{
+		Oid			inputTypeId = input_typeids[i];
+		Oid			targetTypeId = target_typeids[i];
+		CoercionPathType pathtype;
+		Oid			funcId;
+
+		/* no problem if same type */
+		if (inputTypeId == targetTypeId)
+			continue;
+
+		/* accept if target is ANY */
+		if (targetTypeId == ANYOID)
+			continue;
+
+		/* accept if target is polymorphic, for now */
+		if (IsPolymorphicType(targetTypeId))
+		{
+			have_generics = true;	/* do more checking later */
+			continue;
+		}
+
+		/*
+		 * If input is an untyped string constant, assume we can convert it to
+		 * anything.
+		 */
+		if (inputTypeId == UNKNOWNOID)
+			continue;
+
+		/*
+		 * If pg_cast shows that we can coerce, accept.  This test now covers
+		 * both binary-compatible and coercion-function cases.
+		 */
+		pathtype = find_coercion_pathway(targetTypeId, inputTypeId, ccontext,
+										 &funcId);
+		if (pathtype != COERCION_PATH_NONE)
+			continue;
+
+		/*
+		 * If input is RECORD and target is a composite type, assume we can
+		 * coerce (may need tighter checking here)
+		 */
+		if (inputTypeId == RECORDOID &&
+			ISCOMPLEX(targetTypeId))
+			continue;
+
+		/*
+		 * If input is a composite type and target is RECORD, accept
+		 */
+		if (targetTypeId == RECORDOID &&
+			ISCOMPLEX(inputTypeId))
+			continue;
+
+#ifdef NOT_USED					/* not implemented yet */
+
+		/*
+		 * If input is record[] and target is a composite array type, assume
+		 * we can coerce (may need tighter checking here)
+		 */
+		if (inputTypeId == RECORDARRAYOID &&
+			is_complex_array(targetTypeId))
+			continue;
+#endif
+
+		/*
+		 * If input is a composite array type and target is record[], accept
+		 */
+		if (targetTypeId == RECORDARRAYOID &&
+			is_complex_array(inputTypeId))
+			continue;
+
+		/*
+		 * If input is a class type that inherits from target, accept
+		 */
+		if (typeInheritsFrom(inputTypeId, targetTypeId)
+			|| typeIsOfTypedTable(inputTypeId, targetTypeId))
+			continue;
+
+		/*
+		 * Else, cannot coerce at this argument position
+		 */
+		return false;
+	}
+
+	/* If we found any generic argument types, cross-check them */
+	if (have_generics)
+	{
+		if (!check_generic_type_consistency(input_typeids, target_typeids,
+											nargs))
+			return false;
+	}
+
+	return true;
+}
+
+
+/*
+ * Create an expression tree to represent coercion to a domain type.
+ *
+ * 'arg': input expression
+ * 'baseTypeId': base type of domain, if known (pass InvalidOid if caller
+ *		has not bothered to look this up)
+ * 'baseTypeMod': base type typmod of domain, if known (pass -1 if caller
+ *		has not bothered to look this up)
+ * 'typeId': target type to coerce to
+ * 'ccontext': context indicator to control coercions
+ * 'cformat': coercion display format
+ * 'location': coercion request location
+ * 'hideInputCoercion': if true, hide the input coercion under this one.
+ *
+ * If the target type isn't a domain, the given 'arg' is returned as-is.
+ */
+Node *
+coerce_to_domain(Node *arg, Oid baseTypeId, int32 baseTypeMod, Oid typeId,
+				 CoercionContext ccontext, CoercionForm cformat, int location,
+				 bool hideInputCoercion)
+{
+	CoerceToDomain *result;
+
+	/* Get the base type if it hasn't been supplied */
+	if (baseTypeId == InvalidOid)
+		baseTypeId = getBaseTypeAndTypmod(typeId, &baseTypeMod);
+
+	/* If it isn't a domain, return the node as it was passed in */
+	if (baseTypeId == typeId)
+		return arg;
+
+	/* Suppress display of nested coercion steps */
+	if (hideInputCoercion)
+		hide_coercion_node(arg);
+
+	/*
+	 * If the domain applies a typmod to its base type, build the appropriate
+	 * coercion step.  Mark it implicit for display purposes, because we don't
+	 * want it shown separately by ruleutils.c; but the isExplicit flag passed
+	 * to the conversion function depends on the manner in which the domain
+	 * coercion is invoked, so that the semantics of implicit and explicit
+	 * coercion differ.  (Is that really the behavior we want?)
+	 *
+	 * NOTE: because we apply this as part of the fixed expression structure,
+	 * ALTER DOMAIN cannot alter the typtypmod.  But it's unclear that that
+	 * would be safe to do anyway, without lots of knowledge about what the
+	 * base type thinks the typmod means.
+	 */
+	arg = coerce_type_typmod(arg, baseTypeId, baseTypeMod,
+							 ccontext, COERCE_IMPLICIT_CAST, location,
+							 false);
+
+	/*
+	 * Now build the domain coercion node.  This represents run-time checking
+	 * of any constraints currently attached to the domain.  This also ensures
+	 * that the expression is properly labeled as to result type.
+	 */
+	result = makeNode(CoerceToDomain);
+	result->arg = (Expr *) arg;
+	result->resulttype = typeId;
+	result->resulttypmod = -1;	/* currently, always -1 for domains */
+	/* resultcollid will be set by parse_collate.c */
+	result->coercionformat = cformat;
+	result->location = location;
+
+	return (Node *) result;
+}
+
+
+/*
+ * coerce_type_typmod()
+ *		Force a value to a particular typmod, if meaningful and possible.
+ *
+ * This is applied to values that are going to be stored in a relation
+ * (where we have an atttypmod for the column) as well as values being
+ * explicitly CASTed (where the typmod comes from the target type spec).
+ *
+ * The caller must have already ensured that the value is of the correct
+ * type, typically by applying coerce_type.
+ *
+ * ccontext may affect semantics, depending on whether the length coercion
+ * function pays attention to the isExplicit flag it's passed.
+ *
+ * cformat determines the display properties of the generated node (if any).
+ *
+ * If hideInputCoercion is true *and* we generate a node, the input node is
+ * forced to IMPLICIT display form, so that only the typmod coercion node will
+ * be visible when displaying the expression.
+ *
+ * NOTE: this does not need to work on domain types, because any typmod
+ * coercion for a domain is considered to be part of the type coercion
+ * needed to produce the domain value in the first place.  So, no getBaseType.
+ */
+static Node *
+coerce_type_typmod(Node *node, Oid targetTypeId, int32 targetTypMod,
+				   CoercionContext ccontext, CoercionForm cformat,
+				   int location,
+				   bool hideInputCoercion)
+{
+	CoercionPathType pathtype;
+	Oid			funcId;
+
+	/* Skip coercion if already done */
+	if (targetTypMod == exprTypmod(node))
+		return node;
+
+	/* Suppress display of nested coercion steps */
+	if (hideInputCoercion)
+		hide_coercion_node(node);
+
+	/*
+	 * A negative typmod means that no actual coercion is needed, but we still
+	 * want a RelabelType to ensure that the expression exposes the intended
+	 * typmod.
+	 */
+	if (targetTypMod < 0)
+		pathtype = COERCION_PATH_NONE;
+	else
+		pathtype = find_typmod_coercion_function(targetTypeId, &funcId);
+
+	if (pathtype != COERCION_PATH_NONE)
+	{
+		node = build_coercion_expression(node, pathtype, funcId,
+										 targetTypeId, targetTypMod,
+										 ccontext, cformat, location);
+	}
+	else
+	{
+		/*
+		 * We don't need to perform any actual coercion step, but we should
+		 * apply a RelabelType to ensure that the expression exposes the
+		 * intended typmod.
+		 */
+		node = applyRelabelType(node, targetTypeId, targetTypMod,
+								exprCollation(node),
+								cformat, location, false);
+	}
+
+	return node;
+}
+
+/*
+ * Mark a coercion node as IMPLICIT so it will never be displayed by
+ * ruleutils.c.  We use this when we generate a nest of coercion nodes
+ * to implement what is logically one conversion; the inner nodes are
+ * forced to IMPLICIT_CAST format.  This does not change their semantics,
+ * only display behavior.
+ *
+ * It is caller error to call this on something that doesn't have a
+ * CoercionForm field.
+ */
+static void
+hide_coercion_node(Node *node)
+{
+	if (IsA(node, FuncExpr))
+		((FuncExpr *) node)->funcformat = COERCE_IMPLICIT_CAST;
+	else if (IsA(node, RelabelType))
+		((RelabelType *) node)->relabelformat = COERCE_IMPLICIT_CAST;
+	else if (IsA(node, CoerceViaIO))
+		((CoerceViaIO *) node)->coerceformat = COERCE_IMPLICIT_CAST;
+	else if (IsA(node, ArrayCoerceExpr))
+		((ArrayCoerceExpr *) node)->coerceformat = COERCE_IMPLICIT_CAST;
+	else if (IsA(node, ConvertRowtypeExpr))
+		((ConvertRowtypeExpr *) node)->convertformat = COERCE_IMPLICIT_CAST;
+	else if (IsA(node, RowExpr))
+		((RowExpr *) node)->row_format = COERCE_IMPLICIT_CAST;
+	else if (IsA(node, CoerceToDomain))
+		((CoerceToDomain *) node)->coercionformat = COERCE_IMPLICIT_CAST;
+	else
+		elog(ERROR, "unsupported node type: %d", (int) nodeTag(node));
+}
+
+/*
+ * build_coercion_expression()
+ *		Construct an expression tree for applying a pg_cast entry.
+ *
+ * This is used for both type-coercion and length-coercion operations,
+ * since there is no difference in terms of the calling convention.
+ */
+static Node *
+build_coercion_expression(Node *node,
+						  CoercionPathType pathtype,
+						  Oid funcId,
+						  Oid targetTypeId, int32 targetTypMod,
+						  CoercionContext ccontext, CoercionForm cformat,
+						  int location)
+{
+	int			nargs = 0;
+
+	if (OidIsValid(funcId))
+	{
+		HeapTuple	tp;
+		Form_pg_proc procstruct;
+
+		tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcId));
+		if (!HeapTupleIsValid(tp))
+			elog(ERROR, "cache lookup failed for function %u", funcId);
+		procstruct = (Form_pg_proc) GETSTRUCT(tp);
+
+		/*
+		 * These Asserts essentially check that function is a legal coercion
+		 * function.  We can't make the seemingly obvious tests on prorettype
+		 * and proargtypes[0], even in the COERCION_PATH_FUNC case, because of
+		 * various binary-compatibility cases.
+		 */
+		/* Assert(targetTypeId == procstruct->prorettype); */
+		Assert(!procstruct->proretset);
+		Assert(procstruct->prokind == PROKIND_FUNCTION);
+		nargs = procstruct->pronargs;
+		Assert(nargs >= 1 && nargs <= 3);
+		/* Assert(procstruct->proargtypes.values[0] == exprType(node)); */
+		Assert(nargs < 2 || procstruct->proargtypes.values[1] == INT4OID);
+		Assert(nargs < 3 || procstruct->proargtypes.values[2] == BOOLOID);
+
+		ReleaseSysCache(tp);
+	}
+
+	if (pathtype == COERCION_PATH_FUNC)
+	{
+		/* We build an ordinary FuncExpr with special arguments */
+		FuncExpr   *fexpr;
+		List	   *args;
+		Const	   *cons;
+
+		Assert(OidIsValid(funcId));
+
+		args = list_make1(node);
+
+		if (nargs >= 2)
+		{
+			/* Pass target typmod as an int4 constant */
+			cons = makeConst(INT4OID,
+							 -1,
+							 InvalidOid,
+							 sizeof(int32),
+							 Int32GetDatum(targetTypMod),
+							 false,
+							 true);
+
+			args = lappend(args, cons);
+		}
+
+		if (nargs == 3)
+		{
+			/* Pass it a boolean isExplicit parameter, too */
+			cons = makeConst(BOOLOID,
+							 -1,
+							 InvalidOid,
+							 sizeof(bool),
+							 BoolGetDatum(ccontext == COERCION_EXPLICIT),
+							 false,
+							 true);
+
+			args = lappend(args, cons);
+		}
+
+		fexpr = makeFuncExpr(funcId, targetTypeId, args,
+							 InvalidOid, InvalidOid, cformat);
+		fexpr->location = location;
+		return (Node *) fexpr;
+	}
+	else if (pathtype == COERCION_PATH_ARRAYCOERCE)
+	{
+		/* We need to build an ArrayCoerceExpr */
+		ArrayCoerceExpr *acoerce = makeNode(ArrayCoerceExpr);
+		CaseTestExpr *ctest = makeNode(CaseTestExpr);
+		Oid			sourceBaseTypeId;
+		int32		sourceBaseTypeMod;
+		Oid			targetElementType;
+		Node	   *elemexpr;
+
+		/*
+		 * Look through any domain over the source array type.  Note we don't
+		 * expect that the target type is a domain; it must be a plain array.
+		 * (To get to a domain target type, we'll do coerce_to_domain later.)
+		 */
+		sourceBaseTypeMod = exprTypmod(node);
+		sourceBaseTypeId = getBaseTypeAndTypmod(exprType(node),
+												&sourceBaseTypeMod);
+
+		/*
+		 * Set up a CaseTestExpr representing one element of the source array.
+		 * This is an abuse of CaseTestExpr, but it's OK as long as there
+		 * can't be any CaseExpr or ArrayCoerceExpr within the completed
+		 * elemexpr.
+		 */
+		ctest->typeId = get_element_type(sourceBaseTypeId);
+		Assert(OidIsValid(ctest->typeId));
+		ctest->typeMod = sourceBaseTypeMod;
+		ctest->collation = InvalidOid;	/* Assume coercions don't care */
+
+		/* And coerce it to the target element type */
+		targetElementType = get_element_type(targetTypeId);
+		Assert(OidIsValid(targetElementType));
+
+		elemexpr = coerce_to_target_type(NULL,
+										 (Node *) ctest,
+										 ctest->typeId,
+										 targetElementType,
+										 targetTypMod,
+										 ccontext,
+										 cformat,
+										 location);
+		if (elemexpr == NULL)	/* shouldn't happen */
+			elog(ERROR, "failed to coerce array element type as expected");
+
+		acoerce->arg = (Expr *) node;
+		acoerce->elemexpr = (Expr *) elemexpr;
+		acoerce->resulttype = targetTypeId;
+
+		/*
+		 * Label the output as having a particular element typmod only if we
+		 * ended up with a per-element expression that is labeled that way.
+		 */
+		acoerce->resulttypmod = exprTypmod(elemexpr);
+		/* resultcollid will be set by parse_collate.c */
+		acoerce->coerceformat = cformat;
+		acoerce->location = location;
+
+		return (Node *) acoerce;
+	}
+	else if (pathtype == COERCION_PATH_COERCEVIAIO)
+	{
+		/* We need to build a CoerceViaIO node */
+		CoerceViaIO *iocoerce = makeNode(CoerceViaIO);
+
+		Assert(!OidIsValid(funcId));
+
+		iocoerce->arg = (Expr *) node;
+		iocoerce->resulttype = targetTypeId;
+		/* resultcollid will be set by parse_collate.c */
+		iocoerce->coerceformat = cformat;
+		iocoerce->location = location;
+
+		return (Node *) iocoerce;
+	}
+	else
+	{
+		elog(ERROR, "unsupported pathtype %d in build_coercion_expression",
+			 (int) pathtype);
+		return NULL;			/* keep compiler quiet */
+	}
+}
+
+
+/*
+ * coerce_record_to_complex
+ *		Coerce a RECORD to a specific composite type.
+ *
+ * Currently we only support this for inputs that are RowExprs or whole-row
+ * Vars.
+ */
+static Node *
+coerce_record_to_complex(ParseState *pstate, Node *node,
+						 Oid targetTypeId,
+						 CoercionContext ccontext,
+						 CoercionForm cformat,
+						 int location)
+{
+	RowExpr    *rowexpr;
+	Oid			baseTypeId;
+	int32		baseTypeMod = -1;
+	TupleDesc	tupdesc;
+	List	   *args = NIL;
+	List	   *newargs;
+	int			i;
+	int			ucolno;
+	ListCell   *arg;
+
+	if (node && IsA(node, RowExpr))
+	{
+		/*
+		 * Since the RowExpr must be of type RECORD, we needn't worry about it
+		 * containing any dropped columns.
+		 */
+		args = ((RowExpr *) node)->args;
+	}
+	else if (node && IsA(node, Var) &&
+			 ((Var *) node)->varattno == InvalidAttrNumber)
+	{
+		int			rtindex = ((Var *) node)->varno;
+		int			sublevels_up = ((Var *) node)->varlevelsup;
+		int			vlocation = ((Var *) node)->location;
+		ParseNamespaceItem *nsitem;
+
+		nsitem = GetNSItemByRangeTablePosn(pstate, rtindex, sublevels_up);
+		args = expandNSItemVars(nsitem, sublevels_up, vlocation, NULL);
+	}
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_CANNOT_COERCE),
+				 errmsg("cannot cast type %s to %s",
+						format_type_be(RECORDOID),
+						format_type_be(targetTypeId)),
+				 parser_coercion_errposition(pstate, location, node)));
+
+	/*
+	 * Look up the composite type, accounting for possibility that what we are
+	 * given is a domain over composite.
+	 */
+	baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
+	tupdesc = lookup_rowtype_tupdesc(baseTypeId, baseTypeMod);
+
+	/* Process the fields */
+	newargs = NIL;
+	ucolno = 1;
+	arg = list_head(args);
+	for (i = 0; i < tupdesc->natts; i++)
+	{
+		Node	   *expr;
+		Node	   *cexpr;
+		Oid			exprtype;
+		Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+
+		/* Fill in NULLs for dropped columns in rowtype */
+		if (attr->attisdropped)
+		{
+			/*
+			 * can't use atttypid here, but it doesn't really matter what type
+			 * the Const claims to be.
+			 */
+			newargs = lappend(newargs,
+							  makeNullConst(INT4OID, -1, InvalidOid));
+			continue;
+		}
+
+		if (arg == NULL)
+			ereport(ERROR,
+					(errcode(ERRCODE_CANNOT_COERCE),
+					 errmsg("cannot cast type %s to %s",
+							format_type_be(RECORDOID),
+							format_type_be(targetTypeId)),
+					 errdetail("Input has too few columns."),
+					 parser_coercion_errposition(pstate, location, node)));
+		expr = (Node *) lfirst(arg);
+		exprtype = exprType(expr);
+
+		cexpr = coerce_to_target_type(pstate,
+									  expr, exprtype,
+									  attr->atttypid,
+									  attr->atttypmod,
+									  ccontext,
+									  COERCE_IMPLICIT_CAST,
+									  -1);
+		if (cexpr == NULL)
+			ereport(ERROR,
+					(errcode(ERRCODE_CANNOT_COERCE),
+					 errmsg("cannot cast type %s to %s",
+							format_type_be(RECORDOID),
+							format_type_be(targetTypeId)),
+					 errdetail("Cannot cast type %s to %s in column %d.",
+							   format_type_be(exprtype),
+							   format_type_be(attr->atttypid),
+							   ucolno),
+					 parser_coercion_errposition(pstate, location, expr)));
+		newargs = lappend(newargs, cexpr);
+		ucolno++;
+		arg = lnext(args, arg);
+	}
+	if (arg != NULL)
+		ereport(ERROR,
+				(errcode(ERRCODE_CANNOT_COERCE),
+				 errmsg("cannot cast type %s to %s",
+						format_type_be(RECORDOID),
+						format_type_be(targetTypeId)),
+				 errdetail("Input has too many columns."),
+				 parser_coercion_errposition(pstate, location, node)));
+
+	ReleaseTupleDesc(tupdesc);
+
+	rowexpr = makeNode(RowExpr);
+	rowexpr->args = newargs;
+	rowexpr->row_typeid = baseTypeId;
+	rowexpr->row_format = cformat;
+	rowexpr->colnames = NIL;	/* not needed for named target type */
+	rowexpr->location = location;
+
+	/* If target is a domain, apply constraints */
+	if (baseTypeId != targetTypeId)
+	{
+		rowexpr->row_format = COERCE_IMPLICIT_CAST;
+		return coerce_to_domain((Node *) rowexpr,
+								baseTypeId, baseTypeMod,
+								targetTypeId,
+								ccontext, cformat, location,
+								false);
+	}
+
+	return (Node *) rowexpr;
+}
+
+/*
+ * coerce_to_boolean()
+ *		Coerce an argument of a construct that requires boolean input
+ *		(AND, OR, NOT, etc).  Also check that input is not a set.
+ *
+ * Returns the possibly-transformed node tree.
+ *
+ * As with coerce_type, pstate may be NULL if no special unknown-Param
+ * processing is wanted.
+ */
+Node *
+coerce_to_boolean(ParseState *pstate, Node *node,
+				  const char *constructName)
+{
+	Oid			inputTypeId = exprType(node);
+
+	if (inputTypeId != BOOLOID)
+	{
+		Node	   *newnode;
+
+		newnode = coerce_to_target_type(pstate, node, inputTypeId,
+										BOOLOID, -1,
+										COERCION_ASSIGNMENT,
+										COERCE_IMPLICIT_CAST,
+										-1);
+		if (newnode == NULL)
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+			/* translator: first %s is name of a SQL construct, eg WHERE */
+					 errmsg("argument of %s must be type %s, not type %s",
+							constructName, "boolean",
+							format_type_be(inputTypeId)),
+					 parser_errposition(pstate, exprLocation(node))));
+		node = newnode;
+	}
+
+	if (expression_returns_set(node))
+		ereport(ERROR,
+				(errcode(ERRCODE_DATATYPE_MISMATCH),
+		/* translator: %s is name of a SQL construct, eg WHERE */
+				 errmsg("argument of %s must not return a set",
+						constructName),
+				 parser_errposition(pstate, exprLocation(node))));
+
+	return node;
+}
+
+/*
+ * coerce_to_specific_type_typmod()
+ *		Coerce an argument of a construct that requires a specific data type,
+ *		with a specific typmod.  Also check that input is not a set.
+ *
+ * Returns the possibly-transformed node tree.
+ *
+ * As with coerce_type, pstate may be NULL if no special unknown-Param
+ * processing is wanted.
+ */
+Node *
+coerce_to_specific_type_typmod(ParseState *pstate, Node *node,
+							   Oid targetTypeId, int32 targetTypmod,
+							   const char *constructName)
+{
+	Oid			inputTypeId = exprType(node);
+
+	if (inputTypeId != targetTypeId)
+	{
+		Node	   *newnode;
+
+		newnode = coerce_to_target_type(pstate, node, inputTypeId,
+										targetTypeId, targetTypmod,
+										COERCION_ASSIGNMENT,
+										COERCE_IMPLICIT_CAST,
+										-1);
+		if (newnode == NULL)
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+			/* translator: first %s is name of a SQL construct, eg LIMIT */
+					 errmsg("argument of %s must be type %s, not type %s",
+							constructName,
+							format_type_be(targetTypeId),
+							format_type_be(inputTypeId)),
+					 parser_errposition(pstate, exprLocation(node))));
+		node = newnode;
+	}
+
+	if (expression_returns_set(node))
+		ereport(ERROR,
+				(errcode(ERRCODE_DATATYPE_MISMATCH),
+		/* translator: %s is name of a SQL construct, eg LIMIT */
+				 errmsg("argument of %s must not return a set",
+						constructName),
+				 parser_errposition(pstate, exprLocation(node))));
+
+	return node;
+}
+
+/*
+ * coerce_to_specific_type()
+ *		Coerce an argument of a construct that requires a specific data type.
+ *		Also check that input is not a set.
+ *
+ * Returns the possibly-transformed node tree.
+ *
+ * As with coerce_type, pstate may be NULL if no special unknown-Param
+ * processing is wanted.
+ */
+Node *
+coerce_to_specific_type(ParseState *pstate, Node *node,
+						Oid targetTypeId,
+						const char *constructName)
+{
+	return coerce_to_specific_type_typmod(pstate, node,
+										  targetTypeId, -1,
+										  constructName);
+}
+
+/*
+ * parser_coercion_errposition - report coercion error location, if possible
+ *
+ * We prefer to point at the coercion request (CAST, ::, etc) if possible;
+ * but there may be no such location in the case of an implicit coercion.
+ * In that case point at the input expression.
+ *
+ * XXX possibly this is more generally useful than coercion errors;
+ * if so, should rename and place with parser_errposition.
+ */
+int
+parser_coercion_errposition(ParseState *pstate,
+							int coerce_location,
+							Node *input_expr)
+{
+	if (coerce_location >= 0)
+		return parser_errposition(pstate, coerce_location);
+	else
+		return parser_errposition(pstate, exprLocation(input_expr));
+}
+
+
+/*
+ * select_common_type()
+ *		Determine the common supertype of a list of input expressions.
+ *		This is used for determining the output type of CASE, UNION,
+ *		and similar constructs.
+ *
+ * 'exprs' is a *nonempty* list of expressions.  Note that earlier items
+ * in the list will be preferred if there is doubt.
+ * 'context' is a phrase to use in the error message if we fail to select
+ * a usable type.  Pass NULL to have the routine return InvalidOid
+ * rather than throwing an error on failure.
+ * 'which_expr': if not NULL, receives a pointer to the particular input
+ * expression from which the result type was taken.
+ *
+ * Caution: "failure" just means that there were inputs of different type
+ * categories.  It is not guaranteed that all the inputs are coercible to the
+ * selected type; caller must check that (see verify_common_type).
+ */
+Oid
+select_common_type(ParseState *pstate, List *exprs, const char *context,
+				   Node **which_expr)
+{
+	Node	   *pexpr;
+	Oid			ptype;
+	TYPCATEGORY pcategory;
+	bool		pispreferred;
+	ListCell   *lc;
+
+	Assert(exprs != NIL);
+	pexpr = (Node *) linitial(exprs);
+	lc = list_second_cell(exprs);
+	ptype = exprType(pexpr);
+
+	/*
+	 * If all input types are valid and exactly the same, just pick that type.
+	 * This is the only way that we will resolve the result as being a domain
+	 * type; otherwise domains are smashed to their base types for comparison.
+	 */
+	if (ptype != UNKNOWNOID)
+	{
+		for_each_cell(lc, exprs, lc)
+		{
+			Node	   *nexpr = (Node *) lfirst(lc);
+			Oid			ntype = exprType(nexpr);
+
+			if (ntype != ptype)
+				break;
+		}
+		if (lc == NULL)			/* got to the end of the list? */
+		{
+			if (which_expr)
+				*which_expr = pexpr;
+			return ptype;
+		}
+	}
+
+	/*
+	 * Nope, so set up for the full algorithm.  Note that at this point, lc
+	 * points to the first list item with type different from pexpr's; we need
+	 * not re-examine any items the previous loop advanced over.
+	 */
+	ptype = getBaseType(ptype);
+	get_type_category_preferred(ptype, &pcategory, &pispreferred);
+
+	for_each_cell(lc, exprs, lc)
+	{
+		Node	   *nexpr = (Node *) lfirst(lc);
+		Oid			ntype = getBaseType(exprType(nexpr));
+
+		/* move on to next one if no new information... */
+		if (ntype != UNKNOWNOID && ntype != ptype)
+		{
+			TYPCATEGORY ncategory;
+			bool		nispreferred;
+
+			get_type_category_preferred(ntype, &ncategory, &nispreferred);
+			if (ptype == UNKNOWNOID)
+			{
+				/* so far, only unknowns so take anything... */
+				pexpr = nexpr;
+				ptype = ntype;
+				pcategory = ncategory;
+				pispreferred = nispreferred;
+			}
+			else if (ncategory != pcategory)
+			{
+				/*
+				 * both types in different categories? then not much hope...
+				 */
+				if (context == NULL)
+					return InvalidOid;
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+				/*------
+				  translator: first %s is name of a SQL construct, eg CASE */
+						 errmsg("%s types %s and %s cannot be matched",
+								context,
+								format_type_be(ptype),
+								format_type_be(ntype)),
+						 parser_errposition(pstate, exprLocation(nexpr))));
+			}
+			else if (!pispreferred &&
+					 can_coerce_type(1, &ptype, &ntype, COERCION_IMPLICIT) &&
+					 !can_coerce_type(1, &ntype, &ptype, COERCION_IMPLICIT))
+			{
+				/*
+				 * take new type if can coerce to it implicitly but not the
+				 * other way; but if we have a preferred type, stay on it.
+				 */
+				pexpr = nexpr;
+				ptype = ntype;
+				pcategory = ncategory;
+				pispreferred = nispreferred;
+			}
+		}
+	}
+
+	/*
+	 * If all the inputs were UNKNOWN type --- ie, unknown-type literals ---
+	 * then resolve as type TEXT.  This situation comes up with constructs
+	 * like SELECT (CASE WHEN foo THEN 'bar' ELSE 'baz' END); SELECT 'foo'
+	 * UNION SELECT 'bar'; It might seem desirable to leave the construct's
+	 * output type as UNKNOWN, but that really doesn't work, because we'd
+	 * probably end up needing a runtime coercion from UNKNOWN to something
+	 * else, and we usually won't have it.  We need to coerce the unknown
+	 * literals while they are still literals, so a decision has to be made
+	 * now.
+	 */
+	if (ptype == UNKNOWNOID)
+		ptype = TEXTOID;
+
+	if (which_expr)
+		*which_expr = pexpr;
+	return ptype;
+}
+
+/*
+ * select_common_type_from_oids()
+ *		Determine the common supertype of an array of type OIDs.
+ *
+ * This is the same logic as select_common_type(), but working from
+ * an array of type OIDs not a list of expressions.  As in that function,
+ * earlier entries in the array have some preference over later ones.
+ * On failure, return InvalidOid if noerror is true, else throw an error.
+ *
+ * Caution: "failure" just means that there were inputs of different type
+ * categories.  It is not guaranteed that all the inputs are coercible to the
+ * selected type; caller must check that (see verify_common_type_from_oids).
+ *
+ * Note: neither caller will pass any UNKNOWNOID entries, so the tests
+ * for that in this function are dead code.  However, they don't cost much,
+ * and it seems better to keep this logic as close to select_common_type()
+ * as possible.
+ */
+static Oid
+select_common_type_from_oids(int nargs, const Oid *typeids, bool noerror)
+{
+	Oid			ptype;
+	TYPCATEGORY pcategory;
+	bool		pispreferred;
+	int			i = 1;
+
+	Assert(nargs > 0);
+	ptype = typeids[0];
+
+	/* If all input types are valid and exactly the same, pick that type. */
+	if (ptype != UNKNOWNOID)
+	{
+		for (; i < nargs; i++)
+		{
+			if (typeids[i] != ptype)
+				break;
+		}
+		if (i == nargs)
+			return ptype;
+	}
+
+	/*
+	 * Nope, so set up for the full algorithm.  Note that at this point, we
+	 * can skip array entries before "i"; they are all equal to ptype.
+	 */
+	ptype = getBaseType(ptype);
+	get_type_category_preferred(ptype, &pcategory, &pispreferred);
+
+	for (; i < nargs; i++)
+	{
+		Oid			ntype = getBaseType(typeids[i]);
+
+		/* move on to next one if no new information... */
+		if (ntype != UNKNOWNOID && ntype != ptype)
+		{
+			TYPCATEGORY ncategory;
+			bool		nispreferred;
+
+			get_type_category_preferred(ntype, &ncategory, &nispreferred);
+			if (ptype == UNKNOWNOID)
+			{
+				/* so far, only unknowns so take anything... */
+				ptype = ntype;
+				pcategory = ncategory;
+				pispreferred = nispreferred;
+			}
+			else if (ncategory != pcategory)
+			{
+				/*
+				 * both types in different categories? then not much hope...
+				 */
+				if (noerror)
+					return InvalidOid;
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("argument types %s and %s cannot be matched",
+								format_type_be(ptype),
+								format_type_be(ntype))));
+			}
+			else if (!pispreferred &&
+					 can_coerce_type(1, &ptype, &ntype, COERCION_IMPLICIT) &&
+					 !can_coerce_type(1, &ntype, &ptype, COERCION_IMPLICIT))
+			{
+				/*
+				 * take new type if can coerce to it implicitly but not the
+				 * other way; but if we have a preferred type, stay on it.
+				 */
+				ptype = ntype;
+				pcategory = ncategory;
+				pispreferred = nispreferred;
+			}
+		}
+	}
+
+	/* Like select_common_type(), choose TEXT if all inputs were UNKNOWN */
+	if (ptype == UNKNOWNOID)
+		ptype = TEXTOID;
+
+	return ptype;
+}
+
+/*
+ * coerce_to_common_type()
+ *		Coerce an expression to the given type.
+ *
+ * This is used following select_common_type() to coerce the individual
+ * expressions to the desired type.  'context' is a phrase to use in the
+ * error message if we fail to coerce.
+ *
+ * As with coerce_type, pstate may be NULL if no special unknown-Param
+ * processing is wanted.
+ */
+Node *
+coerce_to_common_type(ParseState *pstate, Node *node,
+					  Oid targetTypeId, const char *context)
+{
+	Oid			inputTypeId = exprType(node);
+
+	if (inputTypeId == targetTypeId)
+		return node;			/* no work */
+	if (can_coerce_type(1, &inputTypeId, &targetTypeId, COERCION_IMPLICIT))
+		node = coerce_type(pstate, node, inputTypeId, targetTypeId, -1,
+						   COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1);
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_CANNOT_COERCE),
+		/* translator: first %s is name of a SQL construct, eg CASE */
+				 errmsg("%s could not convert type %s to %s",
+						context,
+						format_type_be(inputTypeId),
+						format_type_be(targetTypeId)),
+				 parser_errposition(pstate, exprLocation(node))));
+	return node;
+}
+
+/*
+ * verify_common_type()
+ *		Verify that all input types can be coerced to a proposed common type.
+ *		Return true if so, false if not all coercions are possible.
+ *
+ * Most callers of select_common_type() don't need to do this explicitly
+ * because the checks will happen while trying to convert input expressions
+ * to the right type, e.g. in coerce_to_common_type().  However, if a separate
+ * check step is needed to validate the applicability of the common type, call
+ * this.
+ */
+bool
+verify_common_type(Oid common_type, List *exprs)
+{
+	ListCell   *lc;
+
+	foreach(lc, exprs)
+	{
+		Node	   *nexpr = (Node *) lfirst(lc);
+		Oid			ntype = exprType(nexpr);
+
+		if (!can_coerce_type(1, &ntype, &common_type, COERCION_IMPLICIT))
+			return false;
+	}
+	return true;
+}
+
+/*
+ * verify_common_type_from_oids()
+ *		As above, but work from an array of type OIDs.
+ */
+static bool
+verify_common_type_from_oids(Oid common_type, int nargs, const Oid *typeids)
+{
+	for (int i = 0; i < nargs; i++)
+	{
+		if (!can_coerce_type(1, &typeids[i], &common_type, COERCION_IMPLICIT))
+			return false;
+	}
+	return true;
+}
+
+/*
+ * select_common_typmod()
+ *		Determine the common typmod of a list of input expressions.
+ *
+ * common_type is the selected common type of the expressions, typically
+ * computed using select_common_type().
+ */
+int32
+select_common_typmod(ParseState *pstate, List *exprs, Oid common_type)
+{
+	ListCell   *lc;
+	bool		first = true;
+	int32		result = -1;
+
+	foreach(lc, exprs)
+	{
+		Node	   *expr = (Node *) lfirst(lc);
+
+		/* Types must match */
+		if (exprType(expr) != common_type)
+			return -1;
+		else if (first)
+		{
+			result = exprTypmod(expr);
+			first = false;
+		}
+		else
+		{
+			/* As soon as we see a non-matching typmod, fall back to -1 */
+			if (result != exprTypmod(expr))
+				return -1;
+		}
+	}
+
+	return result;
+}
+
+/*
+ * check_generic_type_consistency()
+ *		Are the actual arguments potentially compatible with a
+ *		polymorphic function?
+ *
+ * The argument consistency rules are:
+ *
+ * 1) All arguments declared ANYELEMENT must have the same datatype.
+ * 2) All arguments declared ANYARRAY must have the same datatype,
+ *	  which must be a varlena array type.
+ * 3) All arguments declared ANYRANGE must be the same range type.
+ *	  Similarly, all arguments declared ANYMULTIRANGE must be the same
+ *	  multirange type; and if both of these appear, the ANYRANGE type
+ *	  must be the element type of the ANYMULTIRANGE type.
+ * 4) If there are arguments of more than one of these polymorphic types,
+ *	  the array element type and/or range subtype must be the same as each
+ *	  other and the same as the ANYELEMENT type.
+ * 5) ANYENUM is treated the same as ANYELEMENT except that if it is used
+ *	  (alone or in combination with plain ANYELEMENT), we add the extra
+ *	  condition that the ANYELEMENT type must be an enum.
+ * 6) ANYNONARRAY is treated the same as ANYELEMENT except that if it is used,
+ *	  we add the extra condition that the ANYELEMENT type must not be an array.
+ *	  (This is a no-op if used in combination with ANYARRAY or ANYENUM, but
+ *	  is an extra restriction if not.)
+ * 7) All arguments declared ANYCOMPATIBLE must be implicitly castable
+ *	  to a common supertype (chosen as per select_common_type's rules).
+ *	  ANYCOMPATIBLENONARRAY works like ANYCOMPATIBLE but also requires the
+ *	  common supertype to not be an array.  If there are ANYCOMPATIBLEARRAY
+ *	  or ANYCOMPATIBLERANGE or ANYCOMPATIBLEMULTIRANGE arguments, their element
+ *	  types or subtypes are included while making the choice of common supertype.
+ * 8) The resolved type of ANYCOMPATIBLEARRAY arguments will be the array
+ *	  type over the common supertype (which might not be the same array type
+ *	  as any of the original arrays).
+ * 9) All ANYCOMPATIBLERANGE arguments must be the exact same range type
+ *	  (after domain flattening), since we have no preference rule that would
+ *	  let us choose one over another.  Furthermore, that range's subtype
+ *	  must exactly match the common supertype chosen by rule 7.
+ * 10) All ANYCOMPATIBLEMULTIRANGE arguments must be the exact same multirange
+ *	  type (after domain flattening), since we have no preference rule that
+ *	  would let us choose one over another.  Furthermore, if ANYCOMPATIBLERANGE
+ *	  also appears, that range type must be the multirange's element type;
+ *	  otherwise, the multirange's range's subtype must exactly match the
+ *	  common supertype chosen by rule 7.
+ *
+ * Domains over arrays match ANYARRAY, and are immediately flattened to their
+ * base type.  (Thus, for example, we will consider it a match if one ANYARRAY
+ * argument is a domain over int4[] while another one is just int4[].)	Also
+ * notice that such a domain does *not* match ANYNONARRAY.  The same goes
+ * for ANYCOMPATIBLEARRAY and ANYCOMPATIBLENONARRAY.
+ *
+ * Similarly, domains over ranges match ANYRANGE or ANYCOMPATIBLERANGE,
+ * and are immediately flattened to their base type.  Likewise, domains
+ * over multiranges match ANYMULTIRANGE or ANYCOMPATIBLEMULTIRANGE and are
+ * immediately flattened to their base type.
+ *
+ * Note that domains aren't currently considered to match ANYENUM,
+ * even if their base type would match.
+ *
+ * If we have UNKNOWN input (ie, an untyped literal) for any polymorphic
+ * argument, assume it is okay.
+ *
+ * We do not ereport here, but just return false if a rule is violated.
+ */
+bool
+check_generic_type_consistency(const Oid *actual_arg_types,
+							   const Oid *declared_arg_types,
+							   int nargs)
+{
+	Oid			elem_typeid = InvalidOid;
+	Oid			array_typeid = InvalidOid;
+	Oid			range_typeid = InvalidOid;
+	Oid			multirange_typeid = InvalidOid;
+	Oid			anycompatible_range_typeid = InvalidOid;
+	Oid			anycompatible_range_typelem = InvalidOid;
+	Oid			anycompatible_multirange_typeid = InvalidOid;
+	Oid			anycompatible_multirange_typelem = InvalidOid;
+	Oid			range_typelem = InvalidOid;
+	bool		have_anynonarray = false;
+	bool		have_anyenum = false;
+	bool		have_anycompatible_nonarray = false;
+	int			n_anycompatible_args = 0;
+	Oid			anycompatible_actual_types[FUNC_MAX_ARGS];
+
+	/*
+	 * Loop through the arguments to see if we have any that are polymorphic.
+	 * If so, require the actual types to be consistent.
+	 */
+	Assert(nargs <= FUNC_MAX_ARGS);
+	for (int j = 0; j < nargs; j++)
+	{
+		Oid			decl_type = declared_arg_types[j];
+		Oid			actual_type = actual_arg_types[j];
+
+		if (decl_type == ANYELEMENTOID ||
+			decl_type == ANYNONARRAYOID ||
+			decl_type == ANYENUMOID)
+		{
+			if (decl_type == ANYNONARRAYOID)
+				have_anynonarray = true;
+			else if (decl_type == ANYENUMOID)
+				have_anyenum = true;
+			if (actual_type == UNKNOWNOID)
+				continue;
+			if (OidIsValid(elem_typeid) && actual_type != elem_typeid)
+				return false;
+			elem_typeid = actual_type;
+		}
+		else if (decl_type == ANYARRAYOID)
+		{
+			if (actual_type == UNKNOWNOID)
+				continue;
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			if (OidIsValid(array_typeid) && actual_type != array_typeid)
+				return false;
+			array_typeid = actual_type;
+		}
+		else if (decl_type == ANYRANGEOID)
+		{
+			if (actual_type == UNKNOWNOID)
+				continue;
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			if (OidIsValid(range_typeid) && actual_type != range_typeid)
+				return false;
+			range_typeid = actual_type;
+		}
+		else if (decl_type == ANYMULTIRANGEOID)
+		{
+			if (actual_type == UNKNOWNOID)
+				continue;
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			if (OidIsValid(multirange_typeid) && actual_type != multirange_typeid)
+				return false;
+			multirange_typeid = actual_type;
+		}
+		else if (decl_type == ANYCOMPATIBLEOID ||
+				 decl_type == ANYCOMPATIBLENONARRAYOID)
+		{
+			if (decl_type == ANYCOMPATIBLENONARRAYOID)
+				have_anycompatible_nonarray = true;
+			if (actual_type == UNKNOWNOID)
+				continue;
+			/* collect the actual types of non-unknown COMPATIBLE args */
+			anycompatible_actual_types[n_anycompatible_args++] = actual_type;
+		}
+		else if (decl_type == ANYCOMPATIBLEARRAYOID)
+		{
+			Oid			elem_type;
+
+			if (actual_type == UNKNOWNOID)
+				continue;
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			elem_type = get_element_type(actual_type);
+			if (!OidIsValid(elem_type))
+				return false;	/* not an array */
+			/* collect the element type for common-supertype choice */
+			anycompatible_actual_types[n_anycompatible_args++] = elem_type;
+		}
+		else if (decl_type == ANYCOMPATIBLERANGEOID)
+		{
+			if (actual_type == UNKNOWNOID)
+				continue;
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			if (OidIsValid(anycompatible_range_typeid))
+			{
+				/* All ANYCOMPATIBLERANGE arguments must be the same type */
+				if (anycompatible_range_typeid != actual_type)
+					return false;
+			}
+			else
+			{
+				anycompatible_range_typeid = actual_type;
+				anycompatible_range_typelem = get_range_subtype(actual_type);
+				if (!OidIsValid(anycompatible_range_typelem))
+					return false;	/* not a range type */
+				/* collect the subtype for common-supertype choice */
+				anycompatible_actual_types[n_anycompatible_args++] = anycompatible_range_typelem;
+			}
+		}
+		else if (decl_type == ANYCOMPATIBLEMULTIRANGEOID)
+		{
+			if (actual_type == UNKNOWNOID)
+				continue;
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			if (OidIsValid(anycompatible_multirange_typeid))
+			{
+				/* All ANYCOMPATIBLEMULTIRANGE arguments must be the same type */
+				if (anycompatible_multirange_typeid != actual_type)
+					return false;
+			}
+			else
+			{
+				anycompatible_multirange_typeid = actual_type;
+				anycompatible_multirange_typelem = get_multirange_range(actual_type);
+				if (!OidIsValid(anycompatible_multirange_typelem))
+					return false;	/* not a multirange type */
+				/* we'll consider the subtype below */
+			}
+		}
+	}
+
+	/* Get the element type based on the array type, if we have one */
+	if (OidIsValid(array_typeid))
+	{
+		if (array_typeid == ANYARRAYOID)
+		{
+			/*
+			 * Special case for matching ANYARRAY input to an ANYARRAY
+			 * argument: allow it for now.  enforce_generic_type_consistency()
+			 * might complain later, depending on the presence of other
+			 * polymorphic arguments or results, but it will deliver a less
+			 * surprising error message than "function does not exist".
+			 *
+			 * (If you think to change this, note that can_coerce_type will
+			 * consider such a situation as a match, so that we might not even
+			 * get here.)
+			 */
+		}
+		else
+		{
+			Oid			array_typelem;
+
+			array_typelem = get_element_type(array_typeid);
+			if (!OidIsValid(array_typelem))
+				return false;	/* should be an array, but isn't */
+
+			if (!OidIsValid(elem_typeid))
+			{
+				/*
+				 * if we don't have an element type yet, use the one we just
+				 * got
+				 */
+				elem_typeid = array_typelem;
+			}
+			else if (array_typelem != elem_typeid)
+			{
+				/* otherwise, they better match */
+				return false;
+			}
+		}
+	}
+
+	/* Deduce range type from multirange type, or check that they agree */
+	if (OidIsValid(multirange_typeid))
+	{
+		Oid			multirange_typelem;
+
+		multirange_typelem = get_multirange_range(multirange_typeid);
+		if (!OidIsValid(multirange_typelem))
+			return false;		/* should be a multirange, but isn't */
+
+		if (!OidIsValid(range_typeid))
+		{
+			/* If we don't have a range type yet, use the one we just got */
+			range_typeid = multirange_typelem;
+			range_typelem = get_range_subtype(multirange_typelem);
+			if (!OidIsValid(range_typelem))
+				return false;	/* should be a range, but isn't */
+		}
+		else if (multirange_typelem != range_typeid)
+		{
+			/* otherwise, they better match */
+			return false;
+		}
+	}
+
+	/* Get the element type based on the range type, if we have one */
+	if (OidIsValid(range_typeid))
+	{
+		range_typelem = get_range_subtype(range_typeid);
+		if (!OidIsValid(range_typelem))
+			return false;		/* should be a range, but isn't */
+
+		if (!OidIsValid(elem_typeid))
+		{
+			/*
+			 * If we don't have an element type yet, use the one we just got
+			 */
+			elem_typeid = range_typelem;
+		}
+		else if (range_typelem != elem_typeid)
+		{
+			/* otherwise, they better match */
+			return false;
+		}
+	}
+
+	if (have_anynonarray)
+	{
+		/* require the element type to not be an array or domain over array */
+		if (type_is_array_domain(elem_typeid))
+			return false;
+	}
+
+	if (have_anyenum)
+	{
+		/* require the element type to be an enum */
+		if (!type_is_enum(elem_typeid))
+			return false;
+	}
+
+	/* Deduce range type from multirange type, or check that they agree */
+	if (OidIsValid(anycompatible_multirange_typeid))
+	{
+		if (OidIsValid(anycompatible_range_typeid))
+		{
+			if (anycompatible_multirange_typelem !=
+				anycompatible_range_typeid)
+				return false;
+		}
+		else
+		{
+			anycompatible_range_typeid = anycompatible_multirange_typelem;
+			anycompatible_range_typelem = get_range_subtype(anycompatible_range_typeid);
+			if (!OidIsValid(anycompatible_range_typelem))
+				return false;	/* not a range type */
+			/* collect the subtype for common-supertype choice */
+			anycompatible_actual_types[n_anycompatible_args++] =
+				anycompatible_range_typelem;
+		}
+	}
+
+	/* Check matching of ANYCOMPATIBLE-family arguments, if any */
+	if (n_anycompatible_args > 0)
+	{
+		Oid			anycompatible_typeid;
+
+		anycompatible_typeid =
+			select_common_type_from_oids(n_anycompatible_args,
+										 anycompatible_actual_types,
+										 true);
+
+		if (!OidIsValid(anycompatible_typeid))
+			return false;		/* there's definitely no common supertype */
+
+		/* We have to verify that the selected type actually works */
+		if (!verify_common_type_from_oids(anycompatible_typeid,
+										  n_anycompatible_args,
+										  anycompatible_actual_types))
+			return false;
+
+		if (have_anycompatible_nonarray)
+		{
+			/*
+			 * require the anycompatible type to not be an array or domain
+			 * over array
+			 */
+			if (type_is_array_domain(anycompatible_typeid))
+				return false;
+		}
+
+		/*
+		 * The anycompatible type must exactly match the range element type,
+		 * if we were able to identify one. This checks compatibility for
+		 * anycompatiblemultirange too since that also sets
+		 * anycompatible_range_typelem above.
+		 */
+		if (OidIsValid(anycompatible_range_typelem) &&
+			anycompatible_range_typelem != anycompatible_typeid)
+			return false;
+	}
+
+	/* Looks valid */
+	return true;
+}
+
+/*
+ * enforce_generic_type_consistency()
+ *		Make sure a polymorphic function is legally callable, and
+ *		deduce actual argument and result types.
+ *
+ * If any polymorphic pseudotype is used in a function's arguments or
+ * return type, we make sure the actual data types are consistent with
+ * each other.  The argument consistency rules are shown above for
+ * check_generic_type_consistency().
+ *
+ * If we have UNKNOWN input (ie, an untyped literal) for any polymorphic
+ * argument, we attempt to deduce the actual type it should have.  If
+ * successful, we alter that position of declared_arg_types[] so that
+ * make_fn_arguments will coerce the literal to the right thing.
+ *
+ * If we have polymorphic arguments of the ANYCOMPATIBLE family,
+ * we similarly alter declared_arg_types[] entries to show the resolved
+ * common supertype, so that make_fn_arguments will coerce the actual
+ * arguments to the proper type.
+ *
+ * Rules are applied to the function's return type (possibly altering it)
+ * if it is declared as a polymorphic type and there is at least one
+ * polymorphic argument type:
+ *
+ * 1) If return type is ANYELEMENT, and any argument is ANYELEMENT, use the
+ *	  argument's actual type as the function's return type.
+ * 2) If return type is ANYARRAY, and any argument is ANYARRAY, use the
+ *	  argument's actual type as the function's return type.
+ * 3) Similarly, if return type is ANYRANGE or ANYMULTIRANGE, and any
+ *	  argument is ANYRANGE or ANYMULTIRANGE, use that argument's actual type
+ *	  (or the corresponding range or multirange type) as the function's return
+ *	  type.
+ * 4) Otherwise, if return type is ANYELEMENT or ANYARRAY, and there is
+ *	  at least one ANYELEMENT, ANYARRAY, ANYRANGE, or ANYMULTIRANGE input,
+ *	  deduce the return type from those inputs, or throw error if we can't.
+ * 5) Otherwise, if return type is ANYRANGE or ANYMULTIRANGE, throw error.
+ *	  (We have no way to select a specific range type if the arguments don't
+ *	  include ANYRANGE or ANYMULTIRANGE.)
+ * 6) ANYENUM is treated the same as ANYELEMENT except that if it is used
+ *	  (alone or in combination with plain ANYELEMENT), we add the extra
+ *	  condition that the ANYELEMENT type must be an enum.
+ * 7) ANYNONARRAY is treated the same as ANYELEMENT except that if it is used,
+ *	  we add the extra condition that the ANYELEMENT type must not be an array.
+ *	  (This is a no-op if used in combination with ANYARRAY or ANYENUM, but
+ *	  is an extra restriction if not.)
+ * 8) ANYCOMPATIBLE, ANYCOMPATIBLEARRAY, and ANYCOMPATIBLENONARRAY are handled
+ *	  by resolving the common supertype of those arguments (or their element
+ *	  types, for array inputs), and then coercing all those arguments to the
+ *	  common supertype, or the array type over the common supertype for
+ *	  ANYCOMPATIBLEARRAY.
+ * 9) For ANYCOMPATIBLERANGE and ANYCOMPATIBLEMULTIRANGE, there must be at
+ *	  least one non-UNKNOWN input matching those arguments, and all such
+ *	  inputs must be the same range type (or its multirange type, as
+ *	  appropriate), since we cannot deduce a range type from non-range types.
+ *	  Furthermore, the range type's subtype is included while choosing the
+ *	  common supertype for ANYCOMPATIBLE et al, and it must exactly match
+ *	  that common supertype.
+ *
+ * Domains over arrays or ranges match ANYARRAY or ANYRANGE arguments,
+ * respectively, and are immediately flattened to their base type.  (In
+ * particular, if the return type is also ANYARRAY or ANYRANGE, we'll set
+ * it to the base type not the domain type.)  The same is true for
+ * ANYMULTIRANGE, ANYCOMPATIBLEARRAY, ANYCOMPATIBLERANGE, and
+ * ANYCOMPATIBLEMULTIRANGE.
+ *
+ * When allow_poly is false, we are not expecting any of the actual_arg_types
+ * to be polymorphic, and we should not return a polymorphic result type
+ * either.  When allow_poly is true, it is okay to have polymorphic "actual"
+ * arg types, and we can return a matching polymorphic type as the result.
+ * (This case is currently used only to check compatibility of an aggregate's
+ * declaration with the underlying transfn.)
+ *
+ * A special case is that we could see ANYARRAY as an actual_arg_type even
+ * when allow_poly is false (this is possible only because pg_statistic has
+ * columns shown as anyarray in the catalogs).  We allow this to match a
+ * declared ANYARRAY argument, but only if there is no other polymorphic
+ * argument that we would need to match it with, and no need to determine
+ * the element type to infer the result type.  Note this means that functions
+ * taking ANYARRAY had better behave sanely if applied to the pg_statistic
+ * columns; they can't just assume that successive inputs are of the same
+ * actual element type.  There is no similar logic for ANYCOMPATIBLEARRAY;
+ * there isn't a need for it since there are no catalog columns of that type,
+ * so we won't see it as input.  We could consider matching an actual ANYARRAY
+ * input to an ANYCOMPATIBLEARRAY argument, but at present that seems useless
+ * as well, since there's no value in using ANYCOMPATIBLEARRAY unless there's
+ * at least one other ANYCOMPATIBLE-family argument or result.
+ *
+ * Also, if there are no arguments declared to be of polymorphic types,
+ * we'll return the rettype unmodified even if it's polymorphic.  This should
+ * never occur for user-declared functions, because CREATE FUNCTION prevents
+ * it.  But it does happen for some built-in functions, such as array_in().
+ */
+Oid
+enforce_generic_type_consistency(const Oid *actual_arg_types,
+								 Oid *declared_arg_types,
+								 int nargs,
+								 Oid rettype,
+								 bool allow_poly)
+{
+	bool		have_poly_anycompatible = false;
+	bool		have_poly_unknowns = false;
+	Oid			elem_typeid = InvalidOid;
+	Oid			array_typeid = InvalidOid;
+	Oid			range_typeid = InvalidOid;
+	Oid			multirange_typeid = InvalidOid;
+	Oid			anycompatible_typeid = InvalidOid;
+	Oid			anycompatible_array_typeid = InvalidOid;
+	Oid			anycompatible_range_typeid = InvalidOid;
+	Oid			anycompatible_range_typelem = InvalidOid;
+	Oid			anycompatible_multirange_typeid = InvalidOid;
+	Oid			anycompatible_multirange_typelem = InvalidOid;
+	bool		have_anynonarray = (rettype == ANYNONARRAYOID);
+	bool		have_anyenum = (rettype == ANYENUMOID);
+	bool		have_anymultirange = (rettype == ANYMULTIRANGEOID);
+	bool		have_anycompatible_nonarray = (rettype == ANYCOMPATIBLENONARRAYOID);
+	bool		have_anycompatible_array = (rettype == ANYCOMPATIBLEARRAYOID);
+	bool		have_anycompatible_range = (rettype == ANYCOMPATIBLERANGEOID);
+	bool		have_anycompatible_multirange = (rettype == ANYCOMPATIBLEMULTIRANGEOID);
+	int			n_poly_args = 0;	/* this counts all family-1 arguments */
+	int			n_anycompatible_args = 0;	/* this counts only non-unknowns */
+	Oid			anycompatible_actual_types[FUNC_MAX_ARGS];
+
+	/*
+	 * Loop through the arguments to see if we have any that are polymorphic.
+	 * If so, require the actual types to be consistent.
+	 */
+	Assert(nargs <= FUNC_MAX_ARGS);
+	for (int j = 0; j < nargs; j++)
+	{
+		Oid			decl_type = declared_arg_types[j];
+		Oid			actual_type = actual_arg_types[j];
+
+		if (decl_type == ANYELEMENTOID ||
+			decl_type == ANYNONARRAYOID ||
+			decl_type == ANYENUMOID)
+		{
+			n_poly_args++;
+			if (decl_type == ANYNONARRAYOID)
+				have_anynonarray = true;
+			else if (decl_type == ANYENUMOID)
+				have_anyenum = true;
+			if (actual_type == UNKNOWNOID)
+			{
+				have_poly_unknowns = true;
+				continue;
+			}
+			if (allow_poly && decl_type == actual_type)
+				continue;		/* no new information here */
+			if (OidIsValid(elem_typeid) && actual_type != elem_typeid)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("arguments declared \"%s\" are not all alike", "anyelement"),
+						 errdetail("%s versus %s",
+								   format_type_be(elem_typeid),
+								   format_type_be(actual_type))));
+			elem_typeid = actual_type;
+		}
+		else if (decl_type == ANYARRAYOID)
+		{
+			n_poly_args++;
+			if (actual_type == UNKNOWNOID)
+			{
+				have_poly_unknowns = true;
+				continue;
+			}
+			if (allow_poly && decl_type == actual_type)
+				continue;		/* no new information here */
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			if (OidIsValid(array_typeid) && actual_type != array_typeid)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("arguments declared \"%s\" are not all alike", "anyarray"),
+						 errdetail("%s versus %s",
+								   format_type_be(array_typeid),
+								   format_type_be(actual_type))));
+			array_typeid = actual_type;
+		}
+		else if (decl_type == ANYRANGEOID)
+		{
+			n_poly_args++;
+			if (actual_type == UNKNOWNOID)
+			{
+				have_poly_unknowns = true;
+				continue;
+			}
+			if (allow_poly && decl_type == actual_type)
+				continue;		/* no new information here */
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			if (OidIsValid(range_typeid) && actual_type != range_typeid)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("arguments declared \"%s\" are not all alike", "anyrange"),
+						 errdetail("%s versus %s",
+								   format_type_be(range_typeid),
+								   format_type_be(actual_type))));
+			range_typeid = actual_type;
+		}
+		else if (decl_type == ANYMULTIRANGEOID)
+		{
+			n_poly_args++;
+			have_anymultirange = true;
+			if (actual_type == UNKNOWNOID)
+			{
+				have_poly_unknowns = true;
+				continue;
+			}
+			if (allow_poly && decl_type == actual_type)
+				continue;		/* no new information here */
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			if (OidIsValid(multirange_typeid) && actual_type != multirange_typeid)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("arguments declared \"%s\" are not all alike", "anymultirange"),
+						 errdetail("%s versus %s",
+								   format_type_be(multirange_typeid),
+								   format_type_be(actual_type))));
+			multirange_typeid = actual_type;
+		}
+		else if (decl_type == ANYCOMPATIBLEOID ||
+				 decl_type == ANYCOMPATIBLENONARRAYOID)
+		{
+			have_poly_anycompatible = true;
+			if (decl_type == ANYCOMPATIBLENONARRAYOID)
+				have_anycompatible_nonarray = true;
+			if (actual_type == UNKNOWNOID)
+				continue;
+			if (allow_poly && decl_type == actual_type)
+				continue;		/* no new information here */
+			/* collect the actual types of non-unknown COMPATIBLE args */
+			anycompatible_actual_types[n_anycompatible_args++] = actual_type;
+		}
+		else if (decl_type == ANYCOMPATIBLEARRAYOID)
+		{
+			Oid			anycompatible_elem_type;
+
+			have_poly_anycompatible = true;
+			have_anycompatible_array = true;
+			if (actual_type == UNKNOWNOID)
+				continue;
+			if (allow_poly && decl_type == actual_type)
+				continue;		/* no new information here */
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			anycompatible_elem_type = get_element_type(actual_type);
+			if (!OidIsValid(anycompatible_elem_type))
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("argument declared %s is not an array but type %s",
+								"anycompatiblearray",
+								format_type_be(actual_type))));
+			/* collect the element type for common-supertype choice */
+			anycompatible_actual_types[n_anycompatible_args++] = anycompatible_elem_type;
+		}
+		else if (decl_type == ANYCOMPATIBLERANGEOID)
+		{
+			have_poly_anycompatible = true;
+			have_anycompatible_range = true;
+			if (actual_type == UNKNOWNOID)
+				continue;
+			if (allow_poly && decl_type == actual_type)
+				continue;		/* no new information here */
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			if (OidIsValid(anycompatible_range_typeid))
+			{
+				/* All ANYCOMPATIBLERANGE arguments must be the same type */
+				if (anycompatible_range_typeid != actual_type)
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("arguments declared \"%s\" are not all alike", "anycompatiblerange"),
+							 errdetail("%s versus %s",
+									   format_type_be(anycompatible_range_typeid),
+									   format_type_be(actual_type))));
+			}
+			else
+			{
+				anycompatible_range_typeid = actual_type;
+				anycompatible_range_typelem = get_range_subtype(actual_type);
+				if (!OidIsValid(anycompatible_range_typelem))
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("argument declared %s is not a range type but type %s",
+									"anycompatiblerange",
+									format_type_be(actual_type))));
+				/* collect the subtype for common-supertype choice */
+				anycompatible_actual_types[n_anycompatible_args++] = anycompatible_range_typelem;
+			}
+		}
+		else if (decl_type == ANYCOMPATIBLEMULTIRANGEOID)
+		{
+			have_poly_anycompatible = true;
+			have_anycompatible_multirange = true;
+			if (actual_type == UNKNOWNOID)
+				continue;
+			if (allow_poly && decl_type == actual_type)
+				continue;		/* no new information here */
+			actual_type = getBaseType(actual_type); /* flatten domains */
+			if (OidIsValid(anycompatible_multirange_typeid))
+			{
+				/* All ANYCOMPATIBLEMULTIRANGE arguments must be the same type */
+				if (anycompatible_multirange_typeid != actual_type)
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("arguments declared \"%s\" are not all alike", "anycompatiblemultirange"),
+							 errdetail("%s versus %s",
+									   format_type_be(anycompatible_multirange_typeid),
+									   format_type_be(actual_type))));
+			}
+			else
+			{
+				anycompatible_multirange_typeid = actual_type;
+				anycompatible_multirange_typelem = get_multirange_range(actual_type);
+				if (!OidIsValid(anycompatible_multirange_typelem))
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("argument declared %s is not a multirange type but type %s",
+									"anycompatiblemultirange",
+									format_type_be(actual_type))));
+				/* we'll consider the subtype below */
+			}
+		}
+	}
+
+	/*
+	 * Fast Track: if none of the arguments are polymorphic, return the
+	 * unmodified rettype.  Not our job to resolve it if it's polymorphic.
+	 */
+	if (n_poly_args == 0 && !have_poly_anycompatible)
+		return rettype;
+
+	/* Check matching of family-1 polymorphic arguments, if any */
+	if (n_poly_args)
+	{
+		/* Get the element type based on the array type, if we have one */
+		if (OidIsValid(array_typeid))
+		{
+			Oid			array_typelem;
+
+			if (array_typeid == ANYARRAYOID)
+			{
+				/*
+				 * Special case for matching ANYARRAY input to an ANYARRAY
+				 * argument: allow it iff no other arguments are family-1
+				 * polymorphics (otherwise we couldn't be sure whether the
+				 * array element type matches up) and the result type doesn't
+				 * require us to infer a specific element type.
+				 */
+				if (n_poly_args != 1 ||
+					(rettype != ANYARRAYOID &&
+					 IsPolymorphicTypeFamily1(rettype)))
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("cannot determine element type of \"anyarray\" argument")));
+				array_typelem = ANYELEMENTOID;
+			}
+			else
+			{
+				array_typelem = get_element_type(array_typeid);
+				if (!OidIsValid(array_typelem))
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("argument declared %s is not an array but type %s",
+									"anyarray", format_type_be(array_typeid))));
+			}
+
+			if (!OidIsValid(elem_typeid))
+			{
+				/*
+				 * if we don't have an element type yet, use the one we just
+				 * got
+				 */
+				elem_typeid = array_typelem;
+			}
+			else if (array_typelem != elem_typeid)
+			{
+				/* otherwise, they better match */
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("argument declared %s is not consistent with argument declared %s",
+								"anyarray", "anyelement"),
+						 errdetail("%s versus %s",
+								   format_type_be(array_typeid),
+								   format_type_be(elem_typeid))));
+			}
+		}
+
+		/* Deduce range type from multirange type, or vice versa */
+		if (OidIsValid(multirange_typeid))
+		{
+			Oid			multirange_typelem;
+
+			multirange_typelem = get_multirange_range(multirange_typeid);
+			if (!OidIsValid(multirange_typelem))
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("argument declared %s is not a multirange type but type %s",
+								"anymultirange",
+								format_type_be(multirange_typeid))));
+
+			if (!OidIsValid(range_typeid))
+			{
+				/* if we don't have a range type yet, use the one we just got */
+				range_typeid = multirange_typelem;
+			}
+			else if (multirange_typelem != range_typeid)
+			{
+				/* otherwise, they better match */
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("argument declared %s is not consistent with argument declared %s",
+								"anymultirange", "anyrange"),
+						 errdetail("%s versus %s",
+								   format_type_be(multirange_typeid),
+								   format_type_be(range_typeid))));
+			}
+		}
+		else if (have_anymultirange && OidIsValid(range_typeid))
+		{
+			multirange_typeid = get_range_multirange(range_typeid);
+			/* We'll complain below if that didn't work */
+		}
+
+		/* Get the element type based on the range type, if we have one */
+		if (OidIsValid(range_typeid))
+		{
+			Oid			range_typelem;
+
+			range_typelem = get_range_subtype(range_typeid);
+			if (!OidIsValid(range_typelem))
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("argument declared %s is not a range type but type %s",
+								"anyrange",
+								format_type_be(range_typeid))));
+
+			if (!OidIsValid(elem_typeid))
+			{
+				/*
+				 * if we don't have an element type yet, use the one we just
+				 * got
+				 */
+				elem_typeid = range_typelem;
+			}
+			else if (range_typelem != elem_typeid)
+			{
+				/* otherwise, they better match */
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("argument declared %s is not consistent with argument declared %s",
+								"anyrange", "anyelement"),
+						 errdetail("%s versus %s",
+								   format_type_be(range_typeid),
+								   format_type_be(elem_typeid))));
+			}
+		}
+
+		if (!OidIsValid(elem_typeid))
+		{
+			if (allow_poly)
+			{
+				elem_typeid = ANYELEMENTOID;
+				array_typeid = ANYARRAYOID;
+				range_typeid = ANYRANGEOID;
+				multirange_typeid = ANYMULTIRANGEOID;
+			}
+			else
+			{
+				/*
+				 * Only way to get here is if all the family-1 polymorphic
+				 * arguments have UNKNOWN inputs.
+				 */
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("could not determine polymorphic type because input has type %s",
+								"unknown")));
+			}
+		}
+
+		if (have_anynonarray && elem_typeid != ANYELEMENTOID)
+		{
+			/*
+			 * require the element type to not be an array or domain over
+			 * array
+			 */
+			if (type_is_array_domain(elem_typeid))
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("type matched to anynonarray is an array type: %s",
+								format_type_be(elem_typeid))));
+		}
+
+		if (have_anyenum && elem_typeid != ANYELEMENTOID)
+		{
+			/* require the element type to be an enum */
+			if (!type_is_enum(elem_typeid))
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("type matched to anyenum is not an enum type: %s",
+								format_type_be(elem_typeid))));
+		}
+	}
+
+	/* Check matching of family-2 polymorphic arguments, if any */
+	if (have_poly_anycompatible)
+	{
+		/* Deduce range type from multirange type, or vice versa */
+		if (OidIsValid(anycompatible_multirange_typeid))
+		{
+			if (OidIsValid(anycompatible_range_typeid))
+			{
+				if (anycompatible_multirange_typelem !=
+					anycompatible_range_typeid)
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("argument declared %s is not consistent with argument declared %s",
+									"anycompatiblemultirange",
+									"anycompatiblerange"),
+							 errdetail("%s versus %s",
+									   format_type_be(anycompatible_multirange_typeid),
+									   format_type_be(anycompatible_range_typeid))));
+			}
+			else
+			{
+				anycompatible_range_typeid = anycompatible_multirange_typelem;
+				anycompatible_range_typelem = get_range_subtype(anycompatible_range_typeid);
+				if (!OidIsValid(anycompatible_range_typelem))
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("argument declared %s is not a multirange type but type %s",
+									"anycompatiblemultirange",
+									format_type_be(anycompatible_multirange_typeid))));
+				/* this enables element type matching check below */
+				have_anycompatible_range = true;
+				/* collect the subtype for common-supertype choice */
+				anycompatible_actual_types[n_anycompatible_args++] =
+					anycompatible_range_typelem;
+			}
+		}
+		else if (have_anycompatible_multirange &&
+				 OidIsValid(anycompatible_range_typeid))
+		{
+			anycompatible_multirange_typeid = get_range_multirange(anycompatible_range_typeid);
+			/* We'll complain below if that didn't work */
+		}
+
+		if (n_anycompatible_args > 0)
+		{
+			anycompatible_typeid =
+				select_common_type_from_oids(n_anycompatible_args,
+											 anycompatible_actual_types,
+											 false);
+
+			/* We have to verify that the selected type actually works */
+			if (!verify_common_type_from_oids(anycompatible_typeid,
+											  n_anycompatible_args,
+											  anycompatible_actual_types))
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("arguments of anycompatible family cannot be cast to a common type")));
+
+			if (have_anycompatible_array)
+			{
+				anycompatible_array_typeid = get_array_type(anycompatible_typeid);
+				if (!OidIsValid(anycompatible_array_typeid))
+					ereport(ERROR,
+							(errcode(ERRCODE_UNDEFINED_OBJECT),
+							 errmsg("could not find array type for data type %s",
+									format_type_be(anycompatible_typeid))));
+			}
+
+			if (have_anycompatible_range)
+			{
+				/* we can't infer a range type from the others */
+				if (!OidIsValid(anycompatible_range_typeid))
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("could not determine polymorphic type %s because input has type %s",
+									"anycompatiblerange", "unknown")));
+
+				/*
+				 * the anycompatible type must exactly match the range element
+				 * type
+				 */
+				if (anycompatible_range_typelem != anycompatible_typeid)
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("anycompatiblerange type %s does not match anycompatible type %s",
+									format_type_be(anycompatible_range_typeid),
+									format_type_be(anycompatible_typeid))));
+			}
+
+			if (have_anycompatible_multirange)
+			{
+				/* we can't infer a multirange type from the others */
+				if (!OidIsValid(anycompatible_multirange_typeid))
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("could not determine polymorphic type %s because input has type %s",
+									"anycompatiblemultirange", "unknown")));
+
+				/*
+				 * the anycompatible type must exactly match the multirange
+				 * element type
+				 */
+				if (anycompatible_range_typelem != anycompatible_typeid)
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("anycompatiblemultirange type %s does not match anycompatible type %s",
+									format_type_be(anycompatible_multirange_typeid),
+									format_type_be(anycompatible_typeid))));
+			}
+
+			if (have_anycompatible_nonarray)
+			{
+				/*
+				 * require the element type to not be an array or domain over
+				 * array
+				 */
+				if (type_is_array_domain(anycompatible_typeid))
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("type matched to anycompatiblenonarray is an array type: %s",
+									format_type_be(anycompatible_typeid))));
+			}
+		}
+		else
+		{
+			if (allow_poly)
+			{
+				anycompatible_typeid = ANYCOMPATIBLEOID;
+				anycompatible_array_typeid = ANYCOMPATIBLEARRAYOID;
+				anycompatible_range_typeid = ANYCOMPATIBLERANGEOID;
+				anycompatible_multirange_typeid = ANYCOMPATIBLEMULTIRANGEOID;
+			}
+			else
+			{
+				/*
+				 * Only way to get here is if all the family-2 polymorphic
+				 * arguments have UNKNOWN inputs.  Resolve to TEXT as
+				 * select_common_type() would do.  That doesn't license us to
+				 * use TEXTRANGE or TEXTMULTIRANGE, though.
+				 */
+				anycompatible_typeid = TEXTOID;
+				anycompatible_array_typeid = TEXTARRAYOID;
+				if (have_anycompatible_range)
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("could not determine polymorphic type %s because input has type %s",
+									"anycompatiblerange", "unknown")));
+				if (have_anycompatible_multirange)
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("could not determine polymorphic type %s because input has type %s",
+									"anycompatiblemultirange", "unknown")));
+			}
+		}
+
+		/* replace family-2 polymorphic types by selected types */
+		for (int j = 0; j < nargs; j++)
+		{
+			Oid			decl_type = declared_arg_types[j];
+
+			if (decl_type == ANYCOMPATIBLEOID ||
+				decl_type == ANYCOMPATIBLENONARRAYOID)
+				declared_arg_types[j] = anycompatible_typeid;
+			else if (decl_type == ANYCOMPATIBLEARRAYOID)
+				declared_arg_types[j] = anycompatible_array_typeid;
+			else if (decl_type == ANYCOMPATIBLERANGEOID)
+				declared_arg_types[j] = anycompatible_range_typeid;
+			else if (decl_type == ANYCOMPATIBLEMULTIRANGEOID)
+				declared_arg_types[j] = anycompatible_multirange_typeid;
+		}
+	}
+
+	/*
+	 * If we had any UNKNOWN inputs for family-1 polymorphic arguments,
+	 * re-scan to assign correct types to them.
+	 *
+	 * Note: we don't have to consider unknown inputs that were matched to
+	 * family-2 polymorphic arguments, because we forcibly updated their
+	 * declared_arg_types[] positions just above.
+	 */
+	if (have_poly_unknowns)
+	{
+		for (int j = 0; j < nargs; j++)
+		{
+			Oid			decl_type = declared_arg_types[j];
+			Oid			actual_type = actual_arg_types[j];
+
+			if (actual_type != UNKNOWNOID)
+				continue;
+
+			if (decl_type == ANYELEMENTOID ||
+				decl_type == ANYNONARRAYOID ||
+				decl_type == ANYENUMOID)
+				declared_arg_types[j] = elem_typeid;
+			else if (decl_type == ANYARRAYOID)
+			{
+				if (!OidIsValid(array_typeid))
+				{
+					array_typeid = get_array_type(elem_typeid);
+					if (!OidIsValid(array_typeid))
+						ereport(ERROR,
+								(errcode(ERRCODE_UNDEFINED_OBJECT),
+								 errmsg("could not find array type for data type %s",
+										format_type_be(elem_typeid))));
+				}
+				declared_arg_types[j] = array_typeid;
+			}
+			else if (decl_type == ANYRANGEOID)
+			{
+				if (!OidIsValid(range_typeid))
+				{
+					/* we can't infer a range type from the others */
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("could not determine polymorphic type %s because input has type %s",
+									"anyrange", "unknown")));
+				}
+				declared_arg_types[j] = range_typeid;
+			}
+			else if (decl_type == ANYMULTIRANGEOID)
+			{
+				if (!OidIsValid(multirange_typeid))
+				{
+					/* we can't infer a multirange type from the others */
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("could not determine polymorphic type %s because input has type %s",
+									"anymultirange", "unknown")));
+				}
+				declared_arg_types[j] = multirange_typeid;
+			}
+		}
+	}
+
+	/* if we return ANYELEMENT use the appropriate argument type */
+	if (rettype == ANYELEMENTOID ||
+		rettype == ANYNONARRAYOID ||
+		rettype == ANYENUMOID)
+		return elem_typeid;
+
+	/* if we return ANYARRAY use the appropriate argument type */
+	if (rettype == ANYARRAYOID)
+	{
+		if (!OidIsValid(array_typeid))
+		{
+			array_typeid = get_array_type(elem_typeid);
+			if (!OidIsValid(array_typeid))
+				ereport(ERROR,
+						(errcode(ERRCODE_UNDEFINED_OBJECT),
+						 errmsg("could not find array type for data type %s",
+								format_type_be(elem_typeid))));
+		}
+		return array_typeid;
+	}
+
+	/* if we return ANYRANGE use the appropriate argument type */
+	if (rettype == ANYRANGEOID)
+	{
+		/* this error is unreachable if the function signature is valid: */
+		if (!OidIsValid(range_typeid))
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg_internal("could not determine polymorphic type %s because input has type %s",
+									 "anyrange", "unknown")));
+		return range_typeid;
+	}
+
+	/* if we return ANYMULTIRANGE use the appropriate argument type */
+	if (rettype == ANYMULTIRANGEOID)
+	{
+		/* this error is unreachable if the function signature is valid: */
+		if (!OidIsValid(multirange_typeid))
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg_internal("could not determine polymorphic type %s because input has type %s",
+									 "anymultirange", "unknown")));
+		return multirange_typeid;
+	}
+
+	/* if we return ANYCOMPATIBLE use the appropriate type */
+	if (rettype == ANYCOMPATIBLEOID ||
+		rettype == ANYCOMPATIBLENONARRAYOID)
+	{
+		/* this error is unreachable if the function signature is valid: */
+		if (!OidIsValid(anycompatible_typeid))
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg_internal("could not identify anycompatible type")));
+		return anycompatible_typeid;
+	}
+
+	/* if we return ANYCOMPATIBLEARRAY use the appropriate type */
+	if (rettype == ANYCOMPATIBLEARRAYOID)
+	{
+		/* this error is unreachable if the function signature is valid: */
+		if (!OidIsValid(anycompatible_array_typeid))
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg_internal("could not identify anycompatiblearray type")));
+		return anycompatible_array_typeid;
+	}
+
+	/* if we return ANYCOMPATIBLERANGE use the appropriate argument type */
+	if (rettype == ANYCOMPATIBLERANGEOID)
+	{
+		/* this error is unreachable if the function signature is valid: */
+		if (!OidIsValid(anycompatible_range_typeid))
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg_internal("could not identify anycompatiblerange type")));
+		return anycompatible_range_typeid;
+	}
+
+	/* if we return ANYCOMPATIBLEMULTIRANGE use the appropriate argument type */
+	if (rettype == ANYCOMPATIBLEMULTIRANGEOID)
+	{
+		/* this error is unreachable if the function signature is valid: */
+		if (!OidIsValid(anycompatible_multirange_typeid))
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg_internal("could not identify anycompatiblemultirange type")));
+		return anycompatible_multirange_typeid;
+	}
+
+	/* we don't return a generic type; send back the original return type */
+	return rettype;
+}
+
+/*
+ * check_valid_polymorphic_signature()
+ *		Is a proposed function signature valid per polymorphism rules?
+ *
+ * Returns NULL if the signature is valid (either ret_type is not polymorphic,
+ * or it can be deduced from the given declared argument types).  Otherwise,
+ * returns a palloc'd, already translated errdetail string saying why not.
+ */
+char *
+check_valid_polymorphic_signature(Oid ret_type,
+								  const Oid *declared_arg_types,
+								  int nargs)
+{
+	if (ret_type == ANYRANGEOID || ret_type == ANYMULTIRANGEOID)
+	{
+		/*
+		 * ANYRANGE and ANYMULTIRANGE require an ANYRANGE or ANYMULTIRANGE
+		 * input, else we can't tell which of several range types with the
+		 * same element type to use.
+		 */
+		for (int i = 0; i < nargs; i++)
+		{
+			if (declared_arg_types[i] == ANYRANGEOID ||
+				declared_arg_types[i] == ANYMULTIRANGEOID)
+				return NULL;	/* OK */
+		}
+		return psprintf(_("A result of type %s requires at least one input of type anyrange or anymultirange."),
+						format_type_be(ret_type));
+	}
+	else if (ret_type == ANYCOMPATIBLERANGEOID || ret_type == ANYCOMPATIBLEMULTIRANGEOID)
+	{
+		/*
+		 * ANYCOMPATIBLERANGE and ANYCOMPATIBLEMULTIRANGE require an
+		 * ANYCOMPATIBLERANGE or ANYCOMPATIBLEMULTIRANGE input, else we can't
+		 * tell which of several range types with the same element type to
+		 * use.
+		 */
+		for (int i = 0; i < nargs; i++)
+		{
+			if (declared_arg_types[i] == ANYCOMPATIBLERANGEOID ||
+				declared_arg_types[i] == ANYCOMPATIBLEMULTIRANGEOID)
+				return NULL;	/* OK */
+		}
+		return psprintf(_("A result of type %s requires at least one input of type anycompatiblerange or anycompatiblemultirange."),
+						format_type_be(ret_type));
+	}
+	else if (IsPolymorphicTypeFamily1(ret_type))
+	{
+		/* Otherwise, any family-1 type can be deduced from any other */
+		for (int i = 0; i < nargs; i++)
+		{
+			if (IsPolymorphicTypeFamily1(declared_arg_types[i]))
+				return NULL;	/* OK */
+		}
+		/* Keep this list in sync with IsPolymorphicTypeFamily1! */
+		return psprintf(_("A result of type %s requires at least one input of type anyelement, anyarray, anynonarray, anyenum, anyrange, or anymultirange."),
+						format_type_be(ret_type));
+	}
+	else if (IsPolymorphicTypeFamily2(ret_type))
+	{
+		/* Otherwise, any family-2 type can be deduced from any other */
+		for (int i = 0; i < nargs; i++)
+		{
+			if (IsPolymorphicTypeFamily2(declared_arg_types[i]))
+				return NULL;	/* OK */
+		}
+		/* Keep this list in sync with IsPolymorphicTypeFamily2! */
+		return psprintf(_("A result of type %s requires at least one input of type anycompatible, anycompatiblearray, anycompatiblenonarray, anycompatiblerange, or anycompatiblemultirange."),
+						format_type_be(ret_type));
+	}
+	else
+		return NULL;			/* OK, ret_type is not polymorphic */
+}
+
+/*
+ * check_valid_internal_signature()
+ *		Is a proposed function signature valid per INTERNAL safety rules?
+ *
+ * Returns NULL if OK, or a suitable error message if ret_type is INTERNAL but
+ * none of the declared arg types are.  (It's unsafe to create such a function
+ * since it would allow invocation of INTERNAL-consuming functions directly
+ * from SQL.)  It's overkill to return the error detail message, since there
+ * is only one possibility, but we do it like this to keep the API similar to
+ * check_valid_polymorphic_signature().
+ */
+char *
+check_valid_internal_signature(Oid ret_type,
+							   const Oid *declared_arg_types,
+							   int nargs)
+{
+	if (ret_type == INTERNALOID)
+	{
+		for (int i = 0; i < nargs; i++)
+		{
+			if (declared_arg_types[i] == ret_type)
+				return NULL;	/* OK */
+		}
+		return pstrdup(_("A result of type internal requires at least one input of type internal."));
+	}
+	else
+		return NULL;			/* OK, ret_type is not INTERNAL */
+}
+
+
+/* TypeCategory()
+ *		Assign a category to the specified type OID.
+ *
+ * NB: this must not return TYPCATEGORY_INVALID.
+ */
+TYPCATEGORY
+TypeCategory(Oid type)
+{
+	char		typcategory;
+	bool		typispreferred;
+
+	get_type_category_preferred(type, &typcategory, &typispreferred);
+	Assert(typcategory != TYPCATEGORY_INVALID);
+	return (TYPCATEGORY) typcategory;
+}
+
+
+/* IsPreferredType()
+ *		Check if this type is a preferred type for the given category.
+ *
+ * If category is TYPCATEGORY_INVALID, then we'll return true for preferred
+ * types of any category; otherwise, only for preferred types of that
+ * category.
+ */
+bool
+IsPreferredType(TYPCATEGORY category, Oid type)
+{
+	char		typcategory;
+	bool		typispreferred;
+
+	get_type_category_preferred(type, &typcategory, &typispreferred);
+	if (category == typcategory || category == TYPCATEGORY_INVALID)
+		return typispreferred;
+	else
+		return false;
+}
+
+
+/* IsBinaryCoercible()
+ *		Check if srctype is binary-coercible to targettype.
+ *
+ * This notion allows us to cheat and directly exchange values without
+ * going through the trouble of calling a conversion function.  Note that
+ * in general, this should only be an implementation shortcut.  Before 7.4,
+ * this was also used as a heuristic for resolving overloaded functions and
+ * operators, but that's basically a bad idea.
+ *
+ * As of 7.3, binary coercibility isn't hardwired into the code anymore.
+ * We consider two types binary-coercible if there is an implicitly
+ * invokable, no-function-needed pg_cast entry.  Also, a domain is always
+ * binary-coercible to its base type, though *not* vice versa (in the other
+ * direction, one must apply domain constraint checks before accepting the
+ * value as legitimate).  We also need to special-case various polymorphic
+ * types.
+ *
+ * This function replaces IsBinaryCompatible(), which was an inherently
+ * symmetric test.  Since the pg_cast entries aren't necessarily symmetric,
+ * the order of the operands is now significant.
+ */
+bool
+IsBinaryCoercible(Oid srctype, Oid targettype)
+{
+	HeapTuple	tuple;
+	Form_pg_cast castForm;
+	bool		result;
+
+	/* Fast path if same type */
+	if (srctype == targettype)
+		return true;
+
+	/* Anything is coercible to ANY or ANYELEMENT or ANYCOMPATIBLE */
+	if (targettype == ANYOID || targettype == ANYELEMENTOID ||
+		targettype == ANYCOMPATIBLEOID)
+		return true;
+
+	/* If srctype is a domain, reduce to its base type */
+	if (OidIsValid(srctype))
+		srctype = getBaseType(srctype);
+
+	/* Somewhat-fast path for domain -> base type case */
+	if (srctype == targettype)
+		return true;
+
+	/* Also accept any array type as coercible to ANY[COMPATIBLE]ARRAY */
+	if (targettype == ANYARRAYOID || targettype == ANYCOMPATIBLEARRAYOID)
+		if (type_is_array(srctype))
+			return true;
+
+	/* Also accept any non-array type as coercible to ANY[COMPATIBLE]NONARRAY */
+	if (targettype == ANYNONARRAYOID || targettype == ANYCOMPATIBLENONARRAYOID)
+		if (!type_is_array(srctype))
+			return true;
+
+	/* Also accept any enum type as coercible to ANYENUM */
+	if (targettype == ANYENUMOID)
+		if (type_is_enum(srctype))
+			return true;
+
+	/* Also accept any range type as coercible to ANY[COMPATIBLE]RANGE */
+	if (targettype == ANYRANGEOID || targettype == ANYCOMPATIBLERANGEOID)
+		if (type_is_range(srctype))
+			return true;
+
+	/* Also, any multirange type is coercible to ANY[COMPATIBLE]MULTIRANGE */
+	if (targettype == ANYMULTIRANGEOID || targettype == ANYCOMPATIBLEMULTIRANGEOID)
+		if (type_is_multirange(srctype))
+			return true;
+
+	/* Also accept any composite type as coercible to RECORD */
+	if (targettype == RECORDOID)
+		if (ISCOMPLEX(srctype))
+			return true;
+
+	/* Also accept any composite array type as coercible to RECORD[] */
+	if (targettype == RECORDARRAYOID)
+		if (is_complex_array(srctype))
+			return true;
+
+	/* Else look in pg_cast */
+	tuple = SearchSysCache2(CASTSOURCETARGET,
+							ObjectIdGetDatum(srctype),
+							ObjectIdGetDatum(targettype));
+	if (!HeapTupleIsValid(tuple))
+		return false;			/* no cast */
+	castForm = (Form_pg_cast) GETSTRUCT(tuple);
+
+	result = (castForm->castmethod == COERCION_METHOD_BINARY &&
+			  castForm->castcontext == COERCION_CODE_IMPLICIT);
+
+	ReleaseSysCache(tuple);
+
+	return result;
+}
+
+
+/*
+ * find_coercion_pathway
+ *		Look for a coercion pathway between two types.
+ *
+ * Currently, this deals only with scalar-type cases; it does not consider
+ * polymorphic types nor casts between composite types.  (Perhaps fold
+ * those in someday?)
+ *
+ * ccontext determines the set of available casts.
+ *
+ * The possible result codes are:
+ *	COERCION_PATH_NONE: failed to find any coercion pathway
+ *				*funcid is set to InvalidOid
+ *	COERCION_PATH_FUNC: apply the coercion function returned in *funcid
+ *	COERCION_PATH_RELABELTYPE: binary-compatible cast, no function needed
+ *				*funcid is set to InvalidOid
+ *	COERCION_PATH_ARRAYCOERCE: need an ArrayCoerceExpr node
+ *				*funcid is set to InvalidOid
+ *	COERCION_PATH_COERCEVIAIO: need a CoerceViaIO node
+ *				*funcid is set to InvalidOid
+ *
+ * Note: COERCION_PATH_RELABELTYPE does not necessarily mean that no work is
+ * needed to do the coercion; if the target is a domain then we may need to
+ * apply domain constraint checking.  If you want to check for a zero-effort
+ * conversion then use IsBinaryCoercible().
+ */
+CoercionPathType
+find_coercion_pathway(Oid targetTypeId, Oid sourceTypeId,
+					  CoercionContext ccontext,
+					  Oid *funcid)
+{
+	CoercionPathType result = COERCION_PATH_NONE;
+	HeapTuple	tuple;
+
+	*funcid = InvalidOid;
+
+	/* Perhaps the types are domains; if so, look at their base types */
+	if (OidIsValid(sourceTypeId))
+		sourceTypeId = getBaseType(sourceTypeId);
+	if (OidIsValid(targetTypeId))
+		targetTypeId = getBaseType(targetTypeId);
+
+	/* Domains are always coercible to and from their base type */
+	if (sourceTypeId == targetTypeId)
+		return COERCION_PATH_RELABELTYPE;
+
+	/* Look in pg_cast */
+	tuple = SearchSysCache2(CASTSOURCETARGET,
+							ObjectIdGetDatum(sourceTypeId),
+							ObjectIdGetDatum(targetTypeId));
+
+	if (HeapTupleIsValid(tuple))
+	{
+		Form_pg_cast castForm = (Form_pg_cast) GETSTRUCT(tuple);
+		CoercionContext castcontext;
+
+		/* convert char value for castcontext to CoercionContext enum */
+		switch (castForm->castcontext)
+		{
+			case COERCION_CODE_IMPLICIT:
+				castcontext = COERCION_IMPLICIT;
+				break;
+			case COERCION_CODE_ASSIGNMENT:
+				castcontext = COERCION_ASSIGNMENT;
+				break;
+			case COERCION_CODE_EXPLICIT:
+				castcontext = COERCION_EXPLICIT;
+				break;
+			default:
+				elog(ERROR, "unrecognized castcontext: %d",
+					 (int) castForm->castcontext);
+				castcontext = 0;	/* keep compiler quiet */
+				break;
+		}
+
+		/* Rely on ordering of enum for correct behavior here */
+		if (ccontext >= castcontext)
+		{
+			switch (castForm->castmethod)
+			{
+				case COERCION_METHOD_FUNCTION:
+					result = COERCION_PATH_FUNC;
+					*funcid = castForm->castfunc;
+					break;
+				case COERCION_METHOD_INOUT:
+					result = COERCION_PATH_COERCEVIAIO;
+					break;
+				case COERCION_METHOD_BINARY:
+					result = COERCION_PATH_RELABELTYPE;
+					break;
+				default:
+					elog(ERROR, "unrecognized castmethod: %d",
+						 (int) castForm->castmethod);
+					break;
+			}
+		}
+
+		ReleaseSysCache(tuple);
+	}
+	else
+	{
+		/*
+		 * If there's no pg_cast entry, perhaps we are dealing with a pair of
+		 * array types.  If so, and if their element types have a conversion
+		 * pathway, report that we can coerce with an ArrayCoerceExpr.
+		 *
+		 * Hack: disallow coercions to oidvector and int2vector, which
+		 * otherwise tend to capture coercions that should go to "real" array
+		 * types.  We want those types to be considered "real" arrays for many
+		 * purposes, but not this one.  (Also, ArrayCoerceExpr isn't
+		 * guaranteed to produce an output that meets the restrictions of
+		 * these datatypes, such as being 1-dimensional.)
+		 */
+		if (targetTypeId != OIDVECTOROID && targetTypeId != INT2VECTOROID)
+		{
+			Oid			targetElem;
+			Oid			sourceElem;
+
+			if ((targetElem = get_element_type(targetTypeId)) != InvalidOid &&
+				(sourceElem = get_element_type(sourceTypeId)) != InvalidOid)
+			{
+				CoercionPathType elempathtype;
+				Oid			elemfuncid;
+
+				elempathtype = find_coercion_pathway(targetElem,
+													 sourceElem,
+													 ccontext,
+													 &elemfuncid);
+				if (elempathtype != COERCION_PATH_NONE)
+				{
+					result = COERCION_PATH_ARRAYCOERCE;
+				}
+			}
+		}
+
+		/*
+		 * If we still haven't found a possibility, consider automatic casting
+		 * using I/O functions.  We allow assignment casts to string types and
+		 * explicit casts from string types to be handled this way. (The
+		 * CoerceViaIO mechanism is a lot more general than that, but this is
+		 * all we want to allow in the absence of a pg_cast entry.) It would
+		 * probably be better to insist on explicit casts in both directions,
+		 * but this is a compromise to preserve something of the pre-8.3
+		 * behavior that many types had implicit (yipes!) casts to text.
+		 */
+		if (result == COERCION_PATH_NONE)
+		{
+			if (ccontext >= COERCION_ASSIGNMENT &&
+				TypeCategory(targetTypeId) == TYPCATEGORY_STRING)
+				result = COERCION_PATH_COERCEVIAIO;
+			else if (ccontext >= COERCION_EXPLICIT &&
+					 TypeCategory(sourceTypeId) == TYPCATEGORY_STRING)
+				result = COERCION_PATH_COERCEVIAIO;
+		}
+	}
+
+	/*
+	 * When parsing PL/pgSQL assignments, allow an I/O cast to be used
+	 * whenever no normal coercion is available.
+	 */
+	if (result == COERCION_PATH_NONE &&
+		ccontext == COERCION_PLPGSQL)
+		result = COERCION_PATH_COERCEVIAIO;
+
+	return result;
+}
+
+
+/*
+ * find_typmod_coercion_function -- does the given type need length coercion?
+ *
+ * If the target type possesses a pg_cast function from itself to itself,
+ * it must need length coercion.
+ *
+ * "bpchar" (ie, char(N)) and "numeric" are examples of such types.
+ *
+ * If the given type is a varlena array type, we do not look for a coercion
+ * function associated directly with the array type, but instead look for
+ * one associated with the element type.  An ArrayCoerceExpr node must be
+ * used to apply such a function.  (Note: currently, it's pointless to
+ * return the funcid in this case, because it'll just get looked up again
+ * in the recursive construction of the ArrayCoerceExpr's elemexpr.)
+ *
+ * We use the same result enum as find_coercion_pathway, but the only possible
+ * result codes are:
+ *	COERCION_PATH_NONE: no length coercion needed
+ *	COERCION_PATH_FUNC: apply the function returned in *funcid
+ *	COERCION_PATH_ARRAYCOERCE: apply the function using ArrayCoerceExpr
+ */
+CoercionPathType
+find_typmod_coercion_function(Oid typeId,
+							  Oid *funcid)
+{
+	CoercionPathType result;
+	Type		targetType;
+	Form_pg_type typeForm;
+	HeapTuple	tuple;
+
+	*funcid = InvalidOid;
+	result = COERCION_PATH_FUNC;
+
+	targetType = typeidType(typeId);
+	typeForm = (Form_pg_type) GETSTRUCT(targetType);
+
+	/* Check for a "true" array type */
+	if (IsTrueArrayType(typeForm))
+	{
+		/* Yes, switch our attention to the element type */
+		typeId = typeForm->typelem;
+		result = COERCION_PATH_ARRAYCOERCE;
+	}
+	ReleaseSysCache(targetType);
+
+	/* Look in pg_cast */
+	tuple = SearchSysCache2(CASTSOURCETARGET,
+							ObjectIdGetDatum(typeId),
+							ObjectIdGetDatum(typeId));
+
+	if (HeapTupleIsValid(tuple))
+	{
+		Form_pg_cast castForm = (Form_pg_cast) GETSTRUCT(tuple);
+
+		*funcid = castForm->castfunc;
+		ReleaseSysCache(tuple);
+	}
+
+	if (!OidIsValid(*funcid))
+		result = COERCION_PATH_NONE;
+
+	return result;
+}
+
+/*
+ * is_complex_array
+ *		Is this type an array of composite?
+ *
+ * Note: this will not return true for record[]; check for RECORDARRAYOID
+ * separately if needed.
+ */
+static bool
+is_complex_array(Oid typid)
+{
+	Oid			elemtype = get_element_type(typid);
+
+	return (OidIsValid(elemtype) && ISCOMPLEX(elemtype));
+}
+
+
+/*
+ * Check whether reltypeId is the row type of a typed table of type
+ * reloftypeId, or is a domain over such a row type.  (This is conceptually
+ * similar to the subtype relationship checked by typeInheritsFrom().)
+ */
+static bool
+typeIsOfTypedTable(Oid reltypeId, Oid reloftypeId)
+{
+	Oid			relid = typeOrDomainTypeRelid(reltypeId);
+	bool		result = false;
+
+	if (relid)
+	{
+		HeapTuple	tp;
+		Form_pg_class reltup;
+
+		tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
+		if (!HeapTupleIsValid(tp))
+			elog(ERROR, "cache lookup failed for relation %u", relid);
+
+		reltup = (Form_pg_class) GETSTRUCT(tp);
+		if (reltup->reloftype == reloftypeId)
+			result = true;
+
+		ReleaseSysCache(tp);
+	}
+
+	return result;
+}