copy stmt or alter stmt in action is not allowed

src/common/backend/parser/gram.y

@@ -15090,7 +15090,15 @@ RuleStmt:	CREATE opt_or_replace RULE name AS
 
 RuleActionList:
 			NOTHING									{ $$ = NIL; }
-			| RuleActionStmt						{ $$ = list_make1($1); }
+			| RuleActionStmt {
+#ifndef ENABLE_MULTIPLE_NODES
+				if (IsA($1, CopyStmt) || IsA($1, AlterTableStmt)) {
+					ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("Unsupported feature"),
+									errdetail("copy stmt or alter stmt in action is not allowed")));
+				}
+#endif
+			    $$ = list_make1($1); 
+            }
 			| '(' RuleActionMulti ')'				{ $$ = $2; }
 		;
 

src/test/regress/expected/rule_test.out

@@ -347,4 +347,12 @@ select * from test_statement;
 drop rule if exists r1 on escapetest;
 drop table if exists test_statement;
 drop table if exists escapetest;
+-- unsupported rule
+create table t1 (id int, name varchar(10));
+create view v1 as select * from t1;
+create rule r1 as on update to v1 do also alter table t1 modify name varchar(20);
+ERROR:  Unsupported feature
+DETAIL:  copy stmt or alter stmt in action is not allowed
+drop table t1 cascade;
+NOTICE:  drop cascades to view v1
 drop schema schema_rule_test cascade;

src/test/regress/sql/rule_test.sql

@@ -225,4 +225,10 @@ drop rule if exists r1 on escapetest;
 drop table if exists test_statement;
 drop table if exists escapetest;
 
+-- unsupported rule
+create table t1 (id int, name varchar(10));
+create view v1 as select * from t1;
+create rule r1 as on update to v1 do also alter table t1 modify name varchar(20);
+drop table t1 cascade;
+
 drop schema schema_rule_test cascade;