Make NoAutoTupling fixes the insertion of unit

docs/rules/NoAutoTupling.md

@@ -4,27 +4,23 @@ id: NoAutoTupling
 title: NoAutoTupling
 ---
 
-> ⚠️ This rule does not work with Scala 2.13 since `-Yno-adapter-args` has been
-> removed.
-
 Adds explicit tuples around argument lists where auto-tupling is occurring.
 
 To use this rule:
 
-- enable `-Ywarn-adapted-args` (note, `-Yno-adapted-args` will fail compilation,
-  which prevents scalafix from running)
-- disable `-Xfatal-warnings`. Unfortunately, the Scala compiler does not support
-  finer grained control over the severity level per message kind. See
-  [scalameta/scalameta#924](https://github.com/scalameta/scalameta/issues/924)
-  for a possible workaround in the near future.
+- enable `-Ywarn-adapted-args` for Scala 2.11 and 2.12 (note, `-Yno-adapted-args` will fail compilation,
+  which prevents scalafix from running). For Scala 2.13, use instead `-Xlint:adapted-args`.
+- enable also `-deprecation` to get warnings on insertions of `Unit`.
 
 ```scala
 // before
 def someMethod(t: (Int, String)) = ...
 someMethod(1, "something")
+val c: Option[Unit] = Some()
 // after
 def someMethod(t: (Int, String)) = ...
 someMethod((1, "something"))
+val c: Option[Unit] = Some(())
 ```
 
 Auto-tupling is a feature that can lead to unexpected results, making code to

project/ScalafixBuild.scala

@@ -60,8 +60,8 @@ object ScalafixBuild extends AutoPlugin with GhpagesKeys {
     }
     val warnAdaptedArgs = Def.setting {
       if (isScala3.value) Nil
-      else if (isScala213.value) Seq("-Xlint:adapted-args")
-      else Seq("-Ywarn-adapted-args")
+      else if (isScala213.value) Seq("-Xlint:adapted-args", "-deprecation")
+      else Seq("-Ywarn-adapted-args", "-deprecation")
     }
     lazy val scaladocOptions = Seq(
       "-groups",

scalafix-rules/src/main/scala/scalafix/internal/rule/NoAutoTupling.scala

@@ -25,6 +25,8 @@ class NoAutoTupling extends SemanticRule("NoAutoTupling") {
         case message
             if message.message.startsWith(
               "Adaptation of argument list by inserting ()"
+            ) || message.message.startsWith(
+              "adaptation of an empty argument list by inserting ()"
             ) =>
           message.position
       }.toSet

scalafix-tests/input/src/main/scala-2/test/NoAutoTupling.scala → scalafix-tests/input/src/main/scala-2/test/noAutoTupling/NoAutoTupling.scala

@@ -1,9 +1,9 @@
 /*
 rules = NoAutoTupling
  */
-package test
+package test.noAutoTupling
 
-class NoAutoTupling2 {
+class NoAutoTupling {
   def a(x: (Int, Boolean)) = x
   a(2, true)
 
@@ -48,7 +48,4 @@ class NoAutoTupling2 {
     Foo(42, "foo", ('z', true))
     Foo.apply(42, "foo", ('z', true))
   }
-
-  //todo: Fix Adaptation of argument list by inserting ()
-  val c: Option[Unit] = Some()
 }

scalafix-tests/input/src/main/scala-2.12/test/NoUnitInsertion.scala → scalafix-tests/input/src/main/scala-2/test/noAutoTupling/NoUnitInsertion.scala

@@ -1,7 +1,7 @@
 /*
 rules = NoAutoTupling
  */
-package test
+package test.noAutoTupling
 
 class NoUnitInsertion {
 

scalafix-tests/output/src/main/scala-2.11/test/NoAutoTupling.scala → scalafix-tests/output/src/main/scala-2.11/test/noAutoTupling/NoAutoTupling.scala

@@ -1,6 +1,6 @@
-package test
+package test.noAutoTupling
 
-class NoAutoTupling2 {
+class NoAutoTupling {
   def a(x: (Int, Boolean)) = x
   a((2, true))
 
@@ -45,8 +45,5 @@ class NoAutoTupling2 {
     Foo(42, "foo", ('z', true))
     Foo.apply(42, "foo", ('z', true))
   }
-
-  //todo: Fix Adaptation of argument list by inserting ()
-  val c: Option[Unit] = Some()
 }
 

scalafix-tests/output/src/main/scala-2.13/test/NoAutoTupling.scala → scalafix-tests/output/src/main/scala-2.12/test/noAutoTupling/NoAutoTupling.scala

@@ -1,6 +1,6 @@
-package test
+package test.noAutoTupling
 
-class NoAutoTupling2 {
+class NoAutoTupling {
   def a(x: (Int, Boolean)) = x
   a((2, true))
 
@@ -45,8 +45,5 @@ class NoAutoTupling2 {
     Foo(42, "foo", ('z', true))
     Foo.apply(42, "foo", ('z', true))
   }
-
-  //todo: Fix Adaptation of argument list by inserting ()
-  val c: Option[Unit] = Some()
 }
 

scalafix-tests/output/src/main/scala-2.12/test/NoAutoTupling.scala → scalafix-tests/output/src/main/scala-2.13/test/noAutoTupling/NoAutoTupling.scala

@@ -1,6 +1,6 @@
-package test
+package test.noAutoTupling
 
-class NoAutoTupling2 {
+class NoAutoTupling {
   def a(x: (Int, Boolean)) = x
   a((2, true))
 
@@ -45,8 +45,5 @@ class NoAutoTupling2 {
     Foo(42, "foo", ('z', true))
     Foo.apply(42, "foo", ('z', true))
   }
-
-  //todo: Fix Adaptation of argument list by inserting ()
-  val c: Option[Unit] = Some()
 }
 

scalafix-tests/output/src/main/scala-2/test/noAutoTupling/NoUnitInsertion.scala

@@ -0,0 +1,24 @@
+package test.noAutoTupling
+
+class NoUnitInsertion {
+
+  val x: Option[Unit] = Option(())
+
+  def a(u: Unit): Unit = u
+  a(())
+
+  def b(x: Int)(u: Unit): Unit = (x, u)
+  b(2)(())
+
+  val c: Unit => Unit =
+    u => u
+  c(())
+
+  case class Foo(u: Unit)
+  Foo(())
+  Foo.apply(())
+
+  case class Bar(i: Int)(u: Unit)
+  Bar.apply(2)(())
+
+}