diff --git a/src/backend/commands/alter.c b/src/backend/commands/alter.c
index 178c979..47c8869 100644
--- a/src/backend/commands/alter.c
+++ b/src/backend/commands/alter.c
@@ -230,7 +230,7 @@ AlterObjectRename_internal(Relation rel, Oid objectId, const char *new_name)
 		Form_pg_proc proc = (Form_pg_proc) GETSTRUCT(oldtup);
 
 		IsThereFunctionInNamespace(new_name, proc->pronargs,
-								   proc->proargtypes, proc->pronamespace);
+								   &proc->proargtypes, proc->pronamespace);
 	}
 	else if (classId == CollationRelationId)
 	{
@@ -609,7 +609,7 @@ AlterObjectNamespace_internal(Relation rel, Oid objid, Oid nspOid)
 		Form_pg_proc proc = (Form_pg_proc) GETSTRUCT(tup);
 
 		IsThereFunctionInNamespace(NameStr(proc->proname), proc->pronargs,
-								   proc->proargtypes, nspOid);
+								   &proc->proargtypes, nspOid);
 	}
 	else if (classId == CollationRelationId)
 	{
diff --git a/src/backend/commands/functioncmds.c b/src/backend/commands/functioncmds.c
index 38187a8..c776758 100644
--- a/src/backend/commands/functioncmds.c
+++ b/src/backend/commands/functioncmds.c
@@ -1626,18 +1626,18 @@ DropCastById(Oid castOid)
  */
 void
 IsThereFunctionInNamespace(const char *proname, int pronargs,
-						   oidvector proargtypes, Oid nspOid)
+						   oidvector *proargtypes, Oid nspOid)
 {
 	/* check for duplicate name (more friendly than unique-index failure) */
 	if (SearchSysCacheExists3(PROCNAMEARGSNSP,
 							  CStringGetDatum(proname),
-							  PointerGetDatum(&proargtypes),
+							  PointerGetDatum(proargtypes),
 							  ObjectIdGetDatum(nspOid)))
 		ereport(ERROR,
 				(errcode(ERRCODE_DUPLICATE_FUNCTION),
 				 errmsg("function %s already exists in schema \"%s\"",
 						funcname_signature_string(proname, pronargs,
-												  NIL, proargtypes.values),
+												  NIL, proargtypes->values),
 						get_namespace_name(nspOid))));
 }
 
diff --git a/src/include/commands/defrem.h b/src/include/commands/defrem.h
index 01d165f..fa9f41f 100644
--- a/src/include/commands/defrem.h
+++ b/src/include/commands/defrem.h
@@ -50,7 +50,7 @@ extern Oid	AlterFunction(AlterFunctionStmt *stmt);
 extern Oid	CreateCast(CreateCastStmt *stmt);
 extern void DropCastById(Oid castOid);
 extern void IsThereFunctionInNamespace(const char *proname, int pronargs,
-						   oidvector proargtypes, Oid nspOid);
+						   oidvector *proargtypes, Oid nspOid);
 extern void ExecuteDoStmt(DoStmt *stmt);
 extern Oid	get_cast_oid(Oid sourcetypeid, Oid targettypeid, bool missing_ok);