Monadic Left Join Syntax does not work with clauses not immediately before

[deusaquilus]

Version: (e.g. 2.3.3)
Module: (e.g. quill-sql)
Database: (e.g. any)

Let's say you have a query that looks like this:

case class Person(name: String, residesIn: String)
case class Country(id:Int, name: String)

quote {
      for {
        p <- query[Person]
        c <- query[Country].leftJoin(_.name == ct.residesIn)
      } yield (p, c)
}

This will work. However, as soon as you introduce something in front of the c <- query[Country]... after the p <- query[Person], for example:

quote {
      for {
        p <- query[Person]
        p1 <- query[Person] if (p.name == p1.name) // introduce something in between p and c
        c <- query[Country].leftJoin(_.name == p.residesIn)
      } yield (p.name, c.map(_.name))
}

Will yield the following error:

Error:(64, 16) exception during macro expansion: 
java.lang.IllegalArgumentException: requirement failed: Found an `ON` table reference of a table that is not available: Set(p). The `ON` condition can only use tables defined through explicit joins.
	at scala.Predef$.require(Predef.scala:224)
	at io.getquill.context.sql.idiom.VerifySqlQuery$$anonfun$io$getquill$context$sql$idiom$VerifySqlQuery$$loop$1$1.apply(VerifySqlQuery.scala:49)
	at io.getquill.context.sql.idiom.VerifySqlQuery$$anonfun$io$getquill$context$sql$idiom$VerifySqlQuery$$loop$1$1.apply(VerifySqlQuery.scala:39)
	at scala.collection.LinearSeqOptimized$class.foldLeft(LinearSeqOptimized.scala:124)
	at scala.collection.immutable.List.foldLeft(List.scala:84)
	at io.getquill.context.sql.idiom.VerifySqlQuery$.io$getquill$context$sql$idiom$VerifySqlQuery$$loop$1(VerifySqlQuery.scala:39)
	at io.getquill.context.sql.idiom.VerifySqlQuery$.verifyFlatJoins(VerifySqlQuery.scala:56)
	at io.getquill.context.sql.idiom.VerifySqlQuery$.verify(VerifySqlQuery.scala:61)
	at io.getquill.context.sql.idiom.VerifySqlQuery$.io$getquill$context$sql$idiom$VerifySqlQuery$$verify(VerifySqlQuery.scala:31)
	at io.getquill.context.sql.idiom.VerifySqlQuery$.apply(VerifySqlQuery.scala:27)
	at io.getquill.context.sql.idiom.SqlIdiom$class.translate(SqlIdiom.scala:30)
	at io.getquill.SQLServerDialect$.translate(SQLServerDialect.scala:37)
	at io.getquill.context.ContextMacro$class.translateStatic(ContextMacro.scala:51)
	at io.getquill.context.ContextMacro$class.translate(ContextMacro.scala:37)
	at io.getquill.context.ContextMacro$class.expand(ContextMacro.scala:24)
	at io.getquill.context.QueryMacro.expand(QueryMacro.scala:8)
	at io.getquill.context.QueryMacro.expandQueryWithMeta(QueryMacro.scala:45)
	at io.getquill.context.QueryMacro.expandQuery(QueryMacro.scala:20)
	at io.getquill.context.QueryMacro.runQuery(QueryMacro.scala:12)
    println(run(q))

Scastie can be found here:
https://scastie.scala-lang.org/deusaquilus/dXxO5hyRRbuAf8Hgz5aghQ

Workaround

Re-arrange the query so that leftJoins only use variables immediately before.

@getquill/maintainers

Edit: More readable.

[deusaquilus]

I see this as addressed in #636. In loop inside verifyFlatJoins inside VerifySqlQuery.scala, isn't it supposed to be:

        case (av, TableContext(_, alias)) => av ++ Set(alias) // i.e. the ++ is added
        case (av, InfixContext(_, alias)) => av ++ Set(alias)
        case (av, QueryContext(_, alias)) => av ++ Set(alias)

As far as I understand, the aliases are supposed to be accumulated...

[deusaquilus]

Looks like I didn't have a proper understanding of the issue. Closing.