Prevent MATCH from following OPTIONAL MATCH

regress/expected/cypher_match.out

@@ -1256,6 +1256,25 @@ SELECT * FROM cypher('cypher_match', $$
  "nobody"   |               |            | "anybody"  |               | 
 (12 rows)
 
+-- Tests to catch match following optional match logic
+-- this syntax is invalid in cypher
+SELECT * FROM cypher('cypher_match', $$
+	OPTIONAL MATCH (n)
+    MATCH (m)
+    RETURN n,m
+ $$) AS (n agtype, m agtype);
+ERROR:  MATCH cannot follow OPTIONAL MATCH
+LINE 1: SELECT * FROM cypher('cypher_match', $$
+                                              ^
+SELECT * FROM cypher('cypher_match', $$
+	MATCH (n)
+	OPTIONAL MATCH (m)
+    MATCH (o)
+    RETURN n,m
+ $$) AS (n agtype, m agtype);
+ERROR:  MATCH cannot follow OPTIONAL MATCH
+LINE 1: SELECT * FROM cypher('cypher_match', $$
+                                              ^
 --
 -- Tests retrieving Var from some parent's cpstate during transformation
 --

regress/sql/cypher_match.sql

@@ -621,6 +621,20 @@ SELECT * FROM cypher('cypher_match', $$
     ORDER BY n, p, m, q
  $$) AS (n agtype, r agtype, p agtype, m agtype, s agtype, q agtype);
 
+-- Tests to catch match following optional match logic
+-- this syntax is invalid in cypher
+SELECT * FROM cypher('cypher_match', $$
+	OPTIONAL MATCH (n)
+    MATCH (m)
+    RETURN n,m
+ $$) AS (n agtype, m agtype);
+
+SELECT * FROM cypher('cypher_match', $$
+	MATCH (n)
+	OPTIONAL MATCH (m)
+    MATCH (o)
+    RETURN n,m
+ $$) AS (n agtype, m agtype);
 
 --
 -- Tests retrieving Var from some parent's cpstate during transformation

src/backend/parser/cypher_clause.c

@@ -2508,6 +2508,23 @@ static Query *transform_cypher_match_pattern(cypher_parsestate *cpstate,
     query = makeNode(Query);
     query->commandType = CMD_SELECT;
 
+    if(self->optional == true && clause->next)
+    {
+        cypher_clause *next = clause->next;
+        if (is_ag_node(next->self, cypher_match))
+        {
+            cypher_match *next_self = (cypher_match *)next->self;
+            if (!next_self->optional)
+            {
+                ereport(ERROR,
+                        (errcode(ERRCODE_SYNTAX_ERROR),
+                         errmsg("MATCH cannot follow OPTIONAL MATCH"),
+                         parser_errposition(pstate,
+                                            exprLocation((Node *) next_self))));
+            }
+        }
+    }
+
     // If there is no previous clause, transform to a general MATCH clause.
     if (self->optional == true && clause->prev != NULL)
     {