Use the new castNode() macro in a number of places.

This is far from a pervasive conversion, but it's a good starting
point.

Author: Peter Eisentraut, with some minor changes by me
Reviewed-By: Tom Lane
Discussion: https://postgr.es/m/c5d387d9-3440-f5e0-f9d4-71d53b9fbe52@2ndquadrant.com

src/backend/commands/aggregatecmds.c

@@ -109,13 +109,13 @@ DefineAggregate(ParseState *pstate, List *name, List *args, bool oldstyle, List
 			aggKind = AGGKIND_ORDERED_SET;
 		else
 			numDirectArgs = 0;
-		args = (List *) linitial(args);
+		args = castNode(List, linitial(args));
 	}
 
 	/* Examine aggregate's definition clauses */
 	foreach(pl, parameters)
 	{
-		DefElem    *defel = (DefElem *) lfirst(pl);
+		DefElem    *defel = castNode(DefElem, lfirst(pl));
 
 		/*
 		 * sfunc1, stype1, and initcond1 are accepted as obsolete spellings

src/backend/commands/analyze.c

@@ -722,9 +722,9 @@ compute_index_stats(Relation onerel, double totalrows,
 		econtext->ecxt_scantuple = slot;
 
 		/* Set up execution state for predicate. */
-		predicate = (List *)
-			ExecPrepareExpr((Expr *) indexInfo->ii_Predicate,
-							estate);
+		predicate = castNode(List,
+							 ExecPrepareExpr((Expr *) indexInfo->ii_Predicate,
+											 estate));
 
 		/* Compute and save index expression values */
 		exprvals = (Datum *) palloc(numrows * attr_cnt * sizeof(Datum));

src/backend/commands/async.c

@@ -1636,7 +1636,7 @@ AtSubCommit_Notify(void)
 	List	   *parentPendingActions;
 	List	   *parentPendingNotifies;
 
-	parentPendingActions = (List *) linitial(upperPendingActions);
+	parentPendingActions = castNode(List, linitial(upperPendingActions));
 	upperPendingActions = list_delete_first(upperPendingActions);
 
 	Assert(list_length(upperPendingActions) ==
@@ -1647,7 +1647,7 @@ AtSubCommit_Notify(void)
 	 */
 	pendingActions = list_concat(parentPendingActions, pendingActions);
 
-	parentPendingNotifies = (List *) linitial(upperPendingNotifies);
+	parentPendingNotifies = castNode(List, linitial(upperPendingNotifies));
 	upperPendingNotifies = list_delete_first(upperPendingNotifies);
 
 	Assert(list_length(upperPendingNotifies) ==
@@ -1679,13 +1679,13 @@ AtSubAbort_Notify(void)
 	 */
 	while (list_length(upperPendingActions) > my_level - 2)
 	{
-		pendingActions = (List *) linitial(upperPendingActions);
+		pendingActions = castNode(List, linitial(upperPendingActions));
 		upperPendingActions = list_delete_first(upperPendingActions);
 	}
 
 	while (list_length(upperPendingNotifies) > my_level - 2)
 	{
-		pendingNotifies = (List *) linitial(upperPendingNotifies);
+		pendingNotifies = castNode(List, linitial(upperPendingNotifies));
 		upperPendingNotifies = list_delete_first(upperPendingNotifies);
 	}
 }

src/backend/commands/collationcmds.c

@@ -61,7 +61,7 @@ DefineCollation(ParseState *pstate, List *names, List *parameters)
 
 	foreach(pl, parameters)
 	{
-		DefElem    *defel = (DefElem *) lfirst(pl);
+		DefElem    *defel = castNode(DefElem, lfirst(pl));
 		DefElem   **defelp;
 
 		if (pg_strcasecmp(defel->defname, "from") == 0)

src/backend/commands/constraint.c

@@ -37,7 +37,7 @@
 Datum
 unique_key_recheck(PG_FUNCTION_ARGS)
 {
-	TriggerData *trigdata = (TriggerData *) fcinfo->context;
+	TriggerData *trigdata = castNode(TriggerData, fcinfo->context);
 	const char *funcname = "unique_key_recheck";
 	HeapTuple	new_row;
 	ItemPointerData tmptid;

src/backend/commands/copy.c

@@ -1026,7 +1026,7 @@ ProcessCopyOptions(ParseState *pstate,
 	/* Extract options from the statement node tree */
 	foreach(option, options)
 	{
-		DefElem    *defel = (DefElem *) lfirst(option);
+		DefElem    *defel = castNode(DefElem, lfirst(option));
 
 		if (strcmp(defel->defname, "format") == 0)
 		{
@@ -1139,7 +1139,7 @@ ProcessCopyOptions(ParseState *pstate,
 						 errmsg("conflicting or redundant options"),
 						 parser_errposition(pstate, defel->location)));
 			if (defel->arg && IsA(defel->arg, List))
-				cstate->force_notnull = (List *) defel->arg;
+				cstate->force_notnull = castNode(List, defel->arg);
 			else
 				ereport(ERROR,
 						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
@@ -1154,7 +1154,7 @@ ProcessCopyOptions(ParseState *pstate,
 						(errcode(ERRCODE_SYNTAX_ERROR),
 						 errmsg("conflicting or redundant options")));
 			if (defel->arg && IsA(defel->arg, List))
-				cstate->force_null = (List *) defel->arg;
+				cstate->force_null = castNode(List, defel->arg);
 			else
 				ereport(ERROR,
 						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
@@ -1176,7 +1176,7 @@ ProcessCopyOptions(ParseState *pstate,
 						 parser_errposition(pstate, defel->location)));
 			cstate->convert_selectively = true;
 			if (defel->arg == NULL || IsA(defel->arg, List))
-				cstate->convert_select = (List *) defel->arg;
+				cstate->convert_select = castNode(List, defel->arg);
 			else
 				ereport(ERROR,
 						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
@@ -1479,7 +1479,7 @@ BeginCopy(ParseState *pstate,
 			/* examine queries to determine which error message to issue */
 			foreach(lc, rewritten)
 			{
-				Query	   *q = (Query *) lfirst(lc);
+				Query	   *q = castNode(Query, lfirst(lc));
 
 				if (q->querySource == QSRC_QUAL_INSTEAD_RULE)
 					ereport(ERROR,
@@ -1496,7 +1496,7 @@ BeginCopy(ParseState *pstate,
 					 errmsg("multi-statement DO INSTEAD rules are not supported for COPY")));
 		}
 
-		query = (Query *) linitial(rewritten);
+		query = castNode(Query, linitial(rewritten));
 
 		/* The grammar allows SELECT INTO, but we don't support that */
 		if (query->utilityStmt != NULL &&

src/backend/commands/createas.c

@@ -224,7 +224,7 @@ ObjectAddress
 ExecCreateTableAs(CreateTableAsStmt *stmt, const char *queryString,
 				  ParamListInfo params, char *completionTag)
 {
-	Query	   *query = (Query *) stmt->query;
+	Query	   *query = castNode(Query, stmt->query);
 	IntoClause *into = stmt->into;
 	bool		is_matview = (into->viewQuery != NULL);
 	DestReceiver *dest;
@@ -261,11 +261,10 @@ ExecCreateTableAs(CreateTableAsStmt *stmt, const char *queryString,
 	 * The contained Query could be a SELECT, or an EXECUTE utility command.
 	 * If the latter, we just pass it off to ExecuteQuery.
 	 */
-	Assert(IsA(query, Query));
 	if (query->commandType == CMD_UTILITY &&
 		IsA(query->utilityStmt, ExecuteStmt))
 	{
-		ExecuteStmt *estmt = (ExecuteStmt *) query->utilityStmt;
+		ExecuteStmt *estmt = castNode(ExecuteStmt, query->utilityStmt);
 
 		Assert(!is_matview);	/* excluded by syntax */
 		ExecuteQuery(estmt, into, queryString, params, dest, completionTag);

src/backend/commands/dropcmds.c

@@ -222,12 +222,10 @@ type_in_list_does_not_exist_skipping(List *typenames, const char **msg,
 
 	foreach(l, typenames)
 	{
-		TypeName   *typeName = (TypeName *) lfirst(l);
+		TypeName   *typeName = castNode(TypeName, lfirst(l));
 
 		if (typeName != NULL)
 		{
-			Assert(IsA(typeName, TypeName));
-
 			if (!OidIsValid(LookupTypeNameOid(NULL, typeName, true)))
 			{
 				/* type doesn't exist, try to find why */

src/backend/commands/explain.c

@@ -1493,25 +1493,25 @@ ExplainNode(PlanState *planstate, List *ancestors,
 										   planstate, es);
 			break;
 		case T_Agg:
-			show_agg_keys((AggState *) planstate, ancestors, es);
+			show_agg_keys(castNode(AggState, planstate), ancestors, es);
 			show_upper_qual(plan->qual, "Filter", planstate, ancestors, es);
 			if (plan->qual)
 				show_instrumentation_count("Rows Removed by Filter", 1,
 										   planstate, es);
 			break;
 		case T_Group:
-			show_group_keys((GroupState *) planstate, ancestors, es);
+			show_group_keys(castNode(GroupState, planstate), ancestors, es);
 			show_upper_qual(plan->qual, "Filter", planstate, ancestors, es);
 			if (plan->qual)
 				show_instrumentation_count("Rows Removed by Filter", 1,
 										   planstate, es);
 			break;
 		case T_Sort:
-			show_sort_keys((SortState *) planstate, ancestors, es);
-			show_sort_info((SortState *) planstate, es);
+			show_sort_keys(castNode(SortState, planstate), ancestors, es);
+			show_sort_info(castNode(SortState, planstate), es);
 			break;
 		case T_MergeAppend:
-			show_merge_append_keys((MergeAppendState *) planstate,
+			show_merge_append_keys(castNode(MergeAppendState, planstate),
 								   ancestors, es);
 			break;
 		case T_Result:
@@ -1523,11 +1523,11 @@ ExplainNode(PlanState *planstate, List *ancestors,
 										   planstate, es);
 			break;
 		case T_ModifyTable:
-			show_modifytable_info((ModifyTableState *) planstate, ancestors,
+			show_modifytable_info(castNode(ModifyTableState, planstate), ancestors,
 								  es);
 			break;
 		case T_Hash:
-			show_hash_info((HashState *) planstate, es);
+			show_hash_info(castNode(HashState, planstate), es);
 			break;
 		default:
 			break;
@@ -2183,7 +2183,6 @@ show_tablesample(TableSampleClause *tsc, PlanState *planstate,
 static void
 show_sort_info(SortState *sortstate, ExplainState *es)
 {
-	Assert(IsA(sortstate, SortState));
 	if (es->analyze && sortstate->sort_Done &&
 		sortstate->tuplesortstate != NULL)
 	{
@@ -2217,7 +2216,6 @@ show_hash_info(HashState *hashstate, ExplainState *es)
 {
 	HashJoinTable hashtable;
 
-	Assert(IsA(hashstate, HashState));
 	hashtable = hashstate->hashtable;
 
 	if (hashtable)

src/backend/commands/functioncmds.c

@@ -578,9 +578,8 @@ update_proconfig_value(ArrayType *a, List *set_items)
 
 	foreach(l, set_items)
 	{
-		VariableSetStmt *sstmt = (VariableSetStmt *) lfirst(l);
+		VariableSetStmt *sstmt = castNode(VariableSetStmt, lfirst(l));
 
-		Assert(IsA(sstmt, VariableSetStmt));
 		if (sstmt->kind == VAR_RESET_ALL)
 			a = NULL;
 		else
@@ -971,9 +970,7 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt *stmt)
 	{
 		ListCell   *lc;
 
-		Assert(IsA(transformDefElem, List));
-
-		foreach(lc, (List *) transformDefElem)
+		foreach(lc, castNode(List, transformDefElem))
 		{
 			Oid			typeid = typenameTypeId(NULL, lfirst(lc));
 			Oid			elt = get_base_element_type(typeid);

src/backend/commands/matview.c

@@ -264,8 +264,7 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 	 * The stored query was rewritten at the time of the MV definition, but
 	 * has not been scribbled on by the planner.
 	 */
-	dataQuery = (Query *) linitial(actions);
-	Assert(IsA(dataQuery, Query));
+	dataQuery = castNode(Query, linitial(actions));
 
 	/*
 	 * Check for active uses of the relation in the current transaction, such

src/backend/commands/opclasscmds.c

@@ -462,13 +462,12 @@ DefineOpClass(CreateOpClassStmt *stmt)
 	 */
 	foreach(l, stmt->items)
 	{
-		CreateOpClassItem *item = lfirst(l);
+		CreateOpClassItem *item = castNode(CreateOpClassItem, lfirst(l));
 		Oid			operOid;
 		Oid			funcOid;
 		Oid			sortfamilyOid;
 		OpFamilyMember *member;
 
-		Assert(IsA(item, CreateOpClassItem));
 		switch (item->itemtype)
 		{
 			case OPCLASS_ITEM_OPERATOR:
@@ -847,13 +846,12 @@ AlterOpFamilyAdd(AlterOpFamilyStmt *stmt, Oid amoid, Oid opfamilyoid,
 	 */
 	foreach(l, items)
 	{
-		CreateOpClassItem *item = lfirst(l);
+		CreateOpClassItem *item = castNode(CreateOpClassItem, lfirst(l));
 		Oid			operOid;
 		Oid			funcOid;
 		Oid			sortfamilyOid;
 		OpFamilyMember *member;
 
-		Assert(IsA(item, CreateOpClassItem));
 		switch (item->itemtype)
 		{
 			case OPCLASS_ITEM_OPERATOR:
@@ -981,12 +979,11 @@ AlterOpFamilyDrop(AlterOpFamilyStmt *stmt, Oid amoid, Oid opfamilyoid,
 	 */
 	foreach(l, items)
 	{
-		CreateOpClassItem *item = lfirst(l);
+		CreateOpClassItem *item = castNode(CreateOpClassItem, lfirst(l));
 		Oid			lefttype,
 					righttype;
 		OpFamilyMember *member;
 
-		Assert(IsA(item, CreateOpClassItem));
 		switch (item->itemtype)
 		{
 			case OPCLASS_ITEM_OPERATOR:

src/backend/commands/tablecmds.c

@@ -5932,12 +5932,11 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 						colName)));
 
 	/* Generate new proposed attoptions (text array) */
-	Assert(IsA(options, List));
 	datum = SysCacheGetAttr(ATTNAME, tuple, Anum_pg_attribute_attoptions,
 							&isnull);
 	newOptions = transformRelOptions(isnull ? (Datum) 0 : datum,
-									 (List *) options, NULL, NULL, false,
-									 isReset);
+									 castNode(List, options), NULL, NULL,
+									 false, isReset);
 	/* Validate new options */
 	(void) attribute_reloptions(newOptions, true);
 
@@ -7141,8 +7140,7 @@ ATExecAlterConstraint(Relation rel, AlterTableCmd *cmd,
 	bool		found = false;
 	ObjectAddress address;
 
-	Assert(IsA(cmd->def, Constraint));
-	cmdcon = (Constraint *) cmd->def;
+	cmdcon = castNode(Constraint, cmd->def);
 
 	conrel = heap_open(ConstraintRelationId, RowExclusiveLock);
 
@@ -9348,9 +9346,7 @@ ATPostAlterTypeParse(Oid oldId, Oid oldRelId, Oid refRelId, char *cmd,
 					IndexStmt  *indstmt;
 					Oid			indoid;
 
-					Assert(IsA(cmd->def, IndexStmt));
-
-					indstmt = (IndexStmt *) cmd->def;
+					indstmt = castNode(IndexStmt, cmd->def);
 					indoid = get_constraint_index(oldId);
 
 					if (!rewrite)
@@ -9373,9 +9369,7 @@ ATPostAlterTypeParse(Oid oldId, Oid oldRelId, Oid refRelId, char *cmd,
 				{
 					Constraint *con;
 
-					Assert(IsA(cmd->def, Constraint));
-
-					con = (Constraint *) cmd->def;
+					con = castNode(Constraint, cmd->def);
 					con->old_pktable_oid = refRelId;
 					/* rewriting neither side of a FK */
 					if (con->contype == CONSTR_FOREIGN &&

src/backend/commands/trigger.c

@@ -340,9 +340,7 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString,
 
 		foreach(lc, varList)
 		{
-			TriggerTransition   *tt = (TriggerTransition *) lfirst(lc);
-
-			Assert(IsA(tt, TriggerTransition));
+			TriggerTransition   *tt = castNode(TriggerTransition, lfirst(lc));
 
 			if (!(tt->isTable))
 				ereport(ERROR,

src/backend/commands/user.c

@@ -1396,11 +1396,9 @@ roleSpecsToIds(List *memberNames)
 
 	foreach(l, memberNames)
 	{
-		RoleSpec   *rolespec = (RoleSpec *) lfirst(l);
+		RoleSpec   *rolespec = castNode(RoleSpec, lfirst(l));
 		Oid			roleid;
 
-		Assert(IsA(rolespec, RoleSpec));
-
 		roleid = get_rolespec_oid(rolespec, false);
 		result = lappend_oid(result, roleid);
 	}

src/backend/commands/view.c

@@ -516,9 +516,8 @@ DefineView(ViewStmt *stmt, const char *queryString,
 
 		foreach(targetList, viewParse->targetList)
 		{
-			TargetEntry *te = (TargetEntry *) lfirst(targetList);
+			TargetEntry *te = castNode(TargetEntry, lfirst(targetList));
 
-			Assert(IsA(te, TargetEntry));
 			/* junk columns don't get aliases */
 			if (te->resjunk)
 				continue;