From e78654402159c0aaa86420b2e2152c23c9938f48 Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Sat, 9 Mar 2024 08:38:24 -0800
Subject: [PATCH] ScannerTokens: add RegionLine if indented further

---
 .../meta/internal/parsers/ScannerTokens.scala | 14 +++-
 .../meta/tests/parsers/dotty/InfixSuite.scala | 65 ++++++++++---------
 2 files changed, 47 insertions(+), 32 deletions(-)

diff --git a/scalameta/parsers/shared/src/main/scala/scala/meta/internal/parsers/ScannerTokens.scala b/scalameta/parsers/shared/src/main/scala/scala/meta/internal/parsers/ScannerTokens.scala
index e60e5c1b5e..ff1e5797b7 100644
--- a/scalameta/parsers/shared/src/main/scala/scala/meta/internal/parsers/ScannerTokens.scala
+++ b/scalameta/parsers/shared/src/main/scala/scala/meta/internal/parsers/ScannerTokens.scala
@@ -911,6 +911,16 @@ final class ScannerTokens(val tokens: Tokens)(implicit dialect: Dialect) {
             if (prevToken.is[Indentation]) _ => None
             else getOutdentIfNeeded(_).fold(getIndentIfNeeded, x => Some(Right(x)))
 
+          def maybeWithLF(regions: List[SepRegion]) = {
+            val res = getIfCanProduceLF(regions, nextIndent)
+            if (res.isEmpty) sepRegionsOrig match {
+              case (ri: SepRegionIndented) :: _ if ri.indent < nextIndent =>
+                Some(Left(RegionLine(nextIndent) :: sepRegionsOrig))
+              case _ => res
+            }
+            else res
+          }
+
           @tailrec
           def iter(regions: List[SepRegion]): Option[Either[List[SepRegion], TokenRef]] = {
             val res = regionsToRes(regions).orElse {
@@ -927,12 +937,12 @@ final class ScannerTokens(val tokens: Tokens)(implicit dialect: Dialect) {
                     if (next.is[Dot]) None
                     else
                       rc.asBody() match {
-                        case Some(body) => getIfCanProduceLF(body :: rs, nextIndent)
+                        case Some(body) => maybeWithLF(body :: rs)
                         case None => iter(rs)
                       }
                   case _ => iter(rs)
                 }
-              case rs => getIfCanProduceLF(rs, nextIndent)
+              case rs => maybeWithLF(rs)
             }
             else res
           }
diff --git a/tests/shared/src/test/scala/scala/meta/tests/parsers/dotty/InfixSuite.scala b/tests/shared/src/test/scala/scala/meta/tests/parsers/dotty/InfixSuite.scala
index f36b72ebf3..62e701b2c2 100644
--- a/tests/shared/src/test/scala/scala/meta/tests/parsers/dotty/InfixSuite.scala
+++ b/tests/shared/src/test/scala/scala/meta/tests/parsers/dotty/InfixSuite.scala
@@ -664,27 +664,27 @@ class InfixSuite extends BaseDottySuite {
     val layout =
       """|object a {
          |  foo.map {
-         |    i => i + 1 *> bar
-         |  }
+         |    i => i + 1
+         |  } *> bar
          |}
          |""".stripMargin
     val tree = Defn.Object(
       Nil,
       tname("a"),
       tpl(
-        Term.Apply(
-          Term.Select(tname("foo"), tname("map")),
-          blk(
-            Term.Function(
-              List(tparam("i")),
-              Term.ApplyInfix(
-                tname("i"),
-                tname("+"),
-                Nil,
-                List(Term.ApplyInfix(int(1), tname("*>"), Nil, List(tname("bar"))))
+        Term.ApplyInfix(
+          Term.Apply(
+            Term.Select(tname("foo"), tname("map")),
+            blk(
+              Term.Function(
+                List(tparam("i")),
+                Term.ApplyInfix(tname("i"), tname("+"), Nil, List(int(1)))
               )
-            )
-          ) :: Nil
+            ) :: Nil
+          ),
+          tname("*>"),
+          Nil,
+          List(tname("bar"))
         )
       )
     )
@@ -704,32 +704,37 @@ class InfixSuite extends BaseDottySuite {
     val layout =
       """|object a {
          |  foo.map {
-         |    i => i + 1 + 2 + 3 *> bar
-         |  }
+         |    i => i + 1 + 2 + 3
+         |  } *> bar
          |}
          |""".stripMargin
     val tree = Defn.Object(
       Nil,
       tname("a"),
       tpl(
-        Term.Apply(
-          Term.Select(tname("foo"), tname("map")),
-          blk(
-            Term.Function(
-              List(tparam("i")),
-              Term.ApplyInfix(
+        Term.ApplyInfix(
+          Term.Apply(
+            Term.Select(tname("foo"), tname("map")),
+            blk(
+              Term.Function(
+                List(tparam("i")),
                 Term.ApplyInfix(
-                  Term.ApplyInfix(tname("i"), tname("+"), Nil, List(int(1))),
+                  Term.ApplyInfix(
+                    Term.ApplyInfix(tname("i"), tname("+"), Nil, List(int(1))),
+                    tname("+"),
+                    Nil,
+                    List(int(2))
+                  ),
                   tname("+"),
                   Nil,
-                  List(int(2))
-                ),
-                tname("+"),
-                Nil,
-                List(Term.ApplyInfix(int(3), tname("*>"), Nil, List(tname("bar"))))
+                  List(int(3))
+                )
               )
-            )
-          ) :: Nil
+            ) :: Nil
+          ),
+          tname("*>"),
+          Nil,
+          List(tname("bar"))
         )
       )
     )