continue

quill-sql-portable/src/main/scala/io/getquill/sql/norm/ExpandJoin.scala

@@ -4,15 +4,23 @@ import io.getquill.ast._
 
 object ExpandJoin extends StatelessTransformer {
 
+  object ExcludedFromNesting {
+    def unapply(ast: Ast) =
+      ast match {
+        case _: Entity   => true
+        case _: Infix    => true
+        case _: FlatJoin => true
+      }
+  }
+
   override def apply(e: Query): Query = {
     e match {
       // Need to nest any map/flatMap clauses found in the `query` slot of a FlatMap or
       // Verifier will cause Found an `ON` table reference of a table that is not available when they are
       // found in this position.
       case fm: FlatMap =>
         super.apply(fm) match {
-          case FlatMap(ent: Entity, alias, body) =>
-            FlatMap(ent, alias, body)
+          case fm @ FlatMap(ExcludedFromNesting(), _, _) => fm
           case FlatMap(ent, alias, body) =>
             FlatMap(Nested(ent), alias, body)
           case other =>
@@ -23,9 +31,8 @@ object ExpandJoin extends StatelessTransformer {
       case Join(typ, a, b, iA, iB, on) =>
         val a1 =
           apply(a) match {
-            case v: Entity => v
-            case v: Infix  => v
-            case other     => Nested(other)
+            case v @ ExcludedFromNesting() => v
+            case other                     => Nested(other)
           }
         val b1 = apply(b)
         FlatMap(a1, iA, Map(FlatJoin(typ, b1, iB, on), iB, Tuple(List(iA, iB))))