Added/Updated tests\bugs\gh_7574_test.py: Confirmed problem on 5.0.0.1049. Checked on 5.0.0.1050 -- all fine.

tests/bugs/gh_7574_test.py

@@ -0,0 +1,59 @@
+#coding:utf-8
+
+"""
+ID:          issue-7574
+ISSUE:       https://github.com/FirebirdSQL/firebird/issues/7574
+TITLE:       Derived table syntax allows dangling "AS"
+NOTES:
+    [17.05.2023] pzotov
+    Confirmed problem on 5.0.0.1049. Checked on 5.0.0.1050 -- all fine.
+"""
+
+import pytest
+from firebird.qa import *
+
+db = db_factory()
+
+test_script = """
+    set heading off;
+    -- All following statements must FAIL since 5.0.0.1050:
+    select i from (select 1 as i from rdb$database) as;
+    -------------------------------------
+    with
+    a as 
+    (select 2 as i from rdb$database)
+    select * from (select i from a) as
+    ;
+    -------------------------------------
+    with recursive
+    r as (
+         select 0 as i from rdb$database
+         UNION ALL
+         select r.i+1 as i from r where r.i < 3
+    )
+    select * from (select i from r) as
+    ;
+"""
+
+act = isql_act('db', test_script, substitutions = [('line \\d+, column \\d+', '')])
+
+expected_stdout = """
+    Statement failed, SQLSTATE = 42000
+    Dynamic SQL Error
+    -SQL error code = -104
+    -Unexpected end of command - line 1, column 49
+    Statement failed, SQLSTATE = 42000
+    Dynamic SQL Error
+    -SQL error code = -104
+    -Unexpected end of command - line 4, column 37
+    Statement failed, SQLSTATE = 42000
+    Dynamic SQL Error
+    -SQL error code = -104
+    -Unexpected end of command - line 7, column 37
+"""
+
+@pytest.mark.version('>=5.0')
+def test_1(act: Action):
+    act.expected_stdout = expected_stdout
+    act.execute(combine_output = True)
+    assert act.clean_stdout == act.clean_expected_stdout