Incorrectly generated SQL containing LEFT JOIN LATERAL

Assume I have a table Matches with the primary key MatchId.

The query

from _ in dbContext.Matches.AsQueryable()
select new { X = (from __ in dbContext.Matches.AsQueryable() select 1).ToList() };

generates

SELECT m."MatchId", 1, m0."MatchId"
FROM "Matches" AS m
LEFT JOIN LATERAL "Matches" AS m0 ON TRUE
ORDER BY m."MatchId", m0."MatchId"

which appears to be invalid:

Npgsql.PostgresException (0x80004005): 42601: syntax error at or near "AS"
   at Npgsql.NpgsqlConnector.<>c__DisplayClass160_0.<<DoReadMessage>g__ReadMessageLong|0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Npgsql.NpgsqlConnector.<>c__DisplayClass160_0.<<DoReadMessage>g__ReadMessageLong|0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Npgsql.NpgsqlDataReader.NextResult(Boolean async, Boolean isConsuming)
   at Npgsql.NpgsqlDataReader.NextResult()
   at Npgsql.NpgsqlCommand.ExecuteReaderAsync(CommandBehavior behavior, Boolean async, CancellationToken cancellationToken)
   at Npgsql.NpgsqlCommand.ExecuteReader(CommandBehavior behavior)
   at Npgsql.NpgsqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
   at System.Data.Common.DbCommand.ExecuteReader()
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReader(RelationalCommandParameterObject parameterObject)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.InitializeReader(DbContext _, Boolean result)
   at Npgsql.EntityFrameworkCore.PostgreSQL.Storage.Internal.NpgsqlExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.MoveNext()
  Exception data:
    Severity: ERROR
    SqlState: 42601
    MessageText: syntax error at or near "AS"
    Position: 87
    File: scan.l
    Line: 1149
    Routine: scanner_yyerror

Provider: Npgsql.EntityFrameworkCore 3.1.4. Database: PostgreSQL 12.2, compiled by Visual C++ build 1914, 64-bit

[PatrikBak]

@roji

did you encounter this in a real-world query (if so, some context could be helpful)?

I came across this issue while debugging a different query. I thought I would report it just in case.

Also, note that you can omit the AsQueryables since DbSets are already IQueryable.

Sadly, I cannot, as I use System.Linq.Async

[smitpatel]

OUTER APPLY will return a single row with null for right when right is empty. Not the case for CROSS JOIN