proposal - plpgsql - FOR over unbound cursor

diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index 71e5400422..34f8c5fea7 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -3471,7 +3471,7 @@ FOR <replaceable>recordvar</replaceable> IN <replaceable>bound_cursorvar</replac
 END LOOP <optional> <replaceable>label</replaceable> </optional>;
 </synopsis>
 
-     The cursor variable must have been bound to some query when it was
+     In this case the cursor variable must have been bound to some query when it was
      declared, and it <emphasis>cannot</emphasis> be open already.  The
      <command>FOR</command> statement automatically opens the cursor, and it closes
      the cursor again when the loop exits.  A list of actual argument value
@@ -3481,6 +3481,21 @@ END LOOP <optional> <replaceable>label</replaceable> </optional>;
      linkend="plpgsql-open-bound-cursor"/>).
    </para>
 
+    <para>
+     There is a variant for iteration over unbound cursors.
+
+<synopsis>
+<optional> &lt;&lt;<replaceable>label</replaceable>&gt;&gt; </optional>
+FOR <replaceable>recordvar</replaceable> IN <replaceable>unbound_cursorvar</replaceable> LOOP
+    <replaceable>statements</replaceable>
+END LOOP <optional> <replaceable>label</replaceable> </optional>;
+</synopsis>
+
+     In this case the cursor have to be assigned to opened cursor portal. The
+     <command>FOR</command> statement in this case doesn't open the cursor and
+     doesn't close the cursor when loop exists.
+   </para>
+
    <para>
      The variable <replaceable>recordvar</replaceable> is automatically
      defined as type <type>record</type> and exists only inside the loop (any
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 9a87cd70f1..392cf9313a 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -2834,6 +2834,45 @@ exec_stmt_forc(PLpgSQL_execstate *estate, PLpgSQL_stmt_forc *stmt)
 	Portal		portal;
 	int			rc;
 
+	curvar = (PLpgSQL_var *) (estate->datums[stmt->curvar]);
+
+	/* ----------
+	 * REFTYPE cursor support - in this case cursor should be opened,
+	 * so it should be not null with active portal - same prereq like
+	 * FETCH stmt.
+	 * ----------
+	 */
+	if (curvar->cursor_explicit_expr == NULL)
+	{
+		MemoryContext oldcontext;
+
+		if (curvar->isnull)
+			ereport(ERROR,
+					(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
+					 errmsg("cursor variable \"%s\" is null", curvar->refname)));
+
+		/* Use eval_mcontext for short-lived string */
+		oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
+		curname = TextDatumGetCString(curvar->value);
+		MemoryContextSwitchTo(oldcontext);
+
+		portal = SPI_cursor_find(curname);
+		if (portal == NULL)
+			ereport(ERROR,
+					(errcode(ERRCODE_UNDEFINED_CURSOR),
+					 errmsg("cursor \"%s\" does not exist", curname)));
+
+		rc = exec_for_query(estate, (PLpgSQL_stmt_forq *) stmt, portal, false);
+
+		/*
+		 * Don't close portal here - who did portal, then he should
+		 * to close portal.
+		 */
+
+		return rc;
+	}
+
+
 	/* ----------
 	 * Get the cursor variable and if it has an assigned name, check
 	 * that it's not in use currently.
diff --git a/src/pl/plpgsql/src/pl_gram.y b/src/pl/plpgsql/src/pl_gram.y
index 6778d0e771..e372945a82 100644
--- a/src/pl/plpgsql/src/pl_gram.y
+++ b/src/pl/plpgsql/src/pl_gram.y
@@ -1405,13 +1405,6 @@ for_control		: for_variable K_IN
 										 errmsg("cursor FOR loop must have only one target variable"),
 										 parser_errposition(@1)));
 
-							/* can't use an unbound cursor this way */
-							if (cursor->cursor_explicit_expr == NULL)
-								ereport(ERROR,
-										(errcode(ERRCODE_SYNTAX_ERROR),
-										 errmsg("cursor FOR loop must use a bound cursor variable"),
-										 parser_errposition(tokloc)));
-
 							/* collect cursor's parameters if any */
 							new->argquery = read_cursor_args(cursor,
 															 K_LOOP,
@@ -3785,7 +3778,7 @@ read_cursor_args(PLpgSQL_var *cursor, int until, const char *expected)
 	bool		any_named = false;
 
 	tok = yylex();
-	if (cursor->cursor_explicit_argrow < 0)
+	if (cursor->cursor_explicit_argrow <= 0)
 	{
 		/* No arguments expected */
 		if (tok == '(')
diff --git a/src/test/regress/expected/plpgsql.out b/src/test/regress/expected/plpgsql.out
index d0a6b630b8..95f6bd72c9 100644
--- a/src/test/regress/expected/plpgsql.out
+++ b/src/test/regress/expected/plpgsql.out
@@ -3607,9 +3607,56 @@ begin
   end loop;
 end;
 $$ language plpgsql;
-ERROR:  cursor FOR loop must use a bound cursor variable
-LINE 5:   for r in c loop
-                   ^
+select forc_bad();
+ERROR:  cursor variable "c" is null
+CONTEXT:  PL/pgSQL function forc_bad() line 5 at FOR over cursor
+-- test FOR-over-refcursor
+create or replace function forc02()
+returns void as $$
+declare
+  c refcursor;
+  r record;
+begin
+  open c for select * from generate_series(1,20) g(v);
+  for r in c
+  loop
+    raise notice 'cycle body one %', r.v;
+    exit when r.v >= 10;
+  end loop;
+
+  for r in c
+  loop
+    raise notice 'cycle body two %', r.v;
+  end loop;
+end
+$$ language plpgsql;
+select forc02();
+NOTICE:  cycle body one 1
+NOTICE:  cycle body one 2
+NOTICE:  cycle body one 3
+NOTICE:  cycle body one 4
+NOTICE:  cycle body one 5
+NOTICE:  cycle body one 6
+NOTICE:  cycle body one 7
+NOTICE:  cycle body one 8
+NOTICE:  cycle body one 9
+NOTICE:  cycle body one 10
+NOTICE:  cycle body two 11
+NOTICE:  cycle body two 12
+NOTICE:  cycle body two 13
+NOTICE:  cycle body two 14
+NOTICE:  cycle body two 15
+NOTICE:  cycle body two 16
+NOTICE:  cycle body two 17
+NOTICE:  cycle body two 18
+NOTICE:  cycle body two 19
+NOTICE:  cycle body two 20
+ forc02 
+--------
+ 
+(1 row)
+
+drop function forc02();
 -- test RETURN QUERY EXECUTE
 create or replace function return_dquery()
 returns setof int as $$
diff --git a/src/test/regress/sql/plpgsql.sql b/src/test/regress/sql/plpgsql.sql
index 07c60c80e4..2ae490c751 100644
--- a/src/test/regress/sql/plpgsql.sql
+++ b/src/test/regress/sql/plpgsql.sql
@@ -2990,6 +2990,33 @@ begin
 end;
 $$ language plpgsql;
 
+select forc_bad();
+
+-- test FOR-over-refcursor
+create or replace function forc02()
+returns void as $$
+declare
+  c refcursor;
+  r record;
+begin
+  open c for select * from generate_series(1,20) g(v);
+  for r in c
+  loop
+    raise notice 'cycle body one %', r.v;
+    exit when r.v >= 10;
+  end loop;
+
+  for r in c
+  loop
+    raise notice 'cycle body two %', r.v;
+  end loop;
+end
+$$ language plpgsql;
+
+select forc02();
+
+drop function forc02();
+
 -- test RETURN QUERY EXECUTE
 
 create or replace function return_dquery()