Corrections of the tabs.

- Change scala 3 only by scala 2 only
- Re-add highlight parts

Author: Dedelweiss

Gemfile.lock

@@ -219,6 +219,8 @@ GEM
       jekyll-feed (~> 0.9)
       jekyll-seo-tag (~> 2.1)
     minitest (5.17.0)
+    nokogiri (1.14.2-x86_64-darwin)
+      racc (~> 1.4)
     nokogiri (1.14.2-x86_64-linux)
       racc (~> 1.4)
     octokit (4.25.1)
@@ -263,6 +265,7 @@ GEM
     zeitwerk (2.6.7)
 
 PLATFORMS
+  x86_64-darwin-22
   x86_64-linux
 
 DEPENDENCIES

_overviews/scala3-migration/incompat-other-changes.md

@@ -108,8 +108,8 @@ The solution is to make the constructor private, since the class is private.
 
 In Scala 3, overriding a concrete def with an abstract def causes subclasses to consider the def abstract, whereas in Scala 2 it was considered as concrete.
 
-{% tabs scala-3-abstract_1 %}
-{% tab 'Scala 3 Only' %}
+{% tabs scala-2-abstract_1 %}
+{% tab 'Scala 2 Only' %}
 
 In the following piece of code, the `bar` method in `C` is considered concrete by the Scala 2.13 compiler but abstract by the Scala 3 compiler, causing the following error.
 ~~~ scala
@@ -121,7 +121,7 @@ trait B extends A {
   def bar(x: Int): Int
 }
 
-class C extends B // Error: class C needs to be abstract, since def bar(x: Int): Int is not defined
+class C extends B // In Scala 3, Error: class C needs to be abstract, since def bar(x: Int): Int is not defined
 ~~~
 
 This behavior was decided in [Dotty issue #4770](https://github.com/lampepfl/dotty/issues/4770).
@@ -135,8 +135,8 @@ An easy fix is simply to remove the abstract def, since in practice it had no ef
 The companion object of a case class does not extend any of the `Function{0-23}` traits anymore.
 In particular, it does not inherit their methods: `tupled`, `curried`, `andThen`, `compose`...
 
-{% tabs companion_1 class=tabs-scala-version %}
-{% tab 'Scala 2' for=companion_1 %}
+{% tabs scala-2-companion_1 %}
+{% tab 'Scala 2 Only' %}
 
 For instance, this is not permitted anymore:
 ~~~ scala
@@ -146,21 +146,23 @@ Foo.curried(1)(true)
 Foo.tupled((2, false))
 ~~~ 
 {% endtab %}
-{% tab 'Scala 3' for=companion_1 %}
+{% endtabs %}
 
 A cross-compiling solution is to explicitly eta-expand the method `Foo.apply`.
-~~~ scala
-case class Foo(x: Int, b: Boolean)
+{% highlight diff %}
 
-(Foo.apply _).curried(1)(true)
-(Foo.apply _).tupled((2, false))
-~~~
+-Foo.curried(1)(true)
++(Foo.apply _).curried(1)(true)
 
-Or, for performance reasons, you can introduce an intermediate function value.
+-Foo.tupled((2, false))
++(Foo.apply _).tupled((2, false))
+{% endhighlight %}
 
-~~~ scala
-case class Foo(x: Int, b: Boolean)
+{% tabs scala-3-companion_2 %}
+{% tab 'Scala 3 Only' %}
 
+Or, for performance reasons, you can introduce an intermediate function value.
+~~~ scala
 val fooCtr: (Int, Boolean) => Foo = (x, b) => Foo(x, b)
 
 fooCtr.curried(1)(true)
@@ -208,45 +210,39 @@ object Location {
   def unapply(location: Location): Location = location
 }
 ~~~
-
-Consequently the following code does not compile anymore.
-~~~ scala
-def tuple(location: Location): (Int, Int) = {
-  Location.unapply(location).get // [E008] Not Found Error: value get is not a member of Location
-}
-~~~
 {% endtab %}
 {% endtabs %}
 
-A possible solution is to use pattern binding:
-
-{% tabs unaply_3 class=tabs-scala-version %}
-{% tab 'Scala 2' for=unaply_3 %}
+{% tabs scala-2-unapply_3 %}
+{% tab 'Scala 2 Only' %}
 
+Consequently the following code does not compile anymore in Scala 3.
 ~~~ scala
 def tuple(location: Location): (Int, Int) = {
-  Location.unapply(location).get
+  Location.unapply(location).get // [E008] In Scala 3, Not Found Error: value get is not a member of Location
 }
 ~~~
 {% endtab %}
-{% tab 'Scala 3' for=unaply_3 %}
-~~~ scala
+{% endtabs %}
+
+A possible solution, in Scala 3, is to use pattern binding:
+
+{% highlight diff %}
 def tuple(location: Location): (Int, Int) = {
-  val Location(lat, lon) = location
-  (lat, lon)
+-  Location.unapply(location).get
++  val Location(lat, lon) = location
++  (lat, lon)
 }
-~~~
-{% endtab %}
-{% endtabs %}
+{% endhighlight %}
 
 ## Invisible Bean Property
 
 The getter and setter methods generated by the `BeanProperty` annotation are now invisible in Scala 3 because their primary use case is the interoperability with Java frameworks.
 
-{% tabs scala-3-bean_1 %}
-{% tab 'Scala 3 Only' %}
+{% tabs scala-2-bean_1 %}
+{% tab 'Scala 2 Only' %}
 
-For instance, in the below example:
+For instance, the below Scala 2 code would fail to compile in Scala 3:
 
 ~~~ scala
 class Pojo() {
@@ -255,36 +251,24 @@ class Pojo() {
 
 val pojo = new Pojo()
 
-pojo.setFooBar("hello") // [E008] Not Found Error: value setFooBar is not a member of Pojo
+pojo.setFooBar("hello") // [E008] In Scala 3, Not Found Error: value setFooBar is not a member of Pojo
 
-println(pojo.getFooBar()) // [E008] Not Found Error: value getFooBar is not a member of Pojo
+println(pojo.getFooBar()) // [E008] In Scala 3, Not Found Error: value getFooBar is not a member of Pojo
 ~~~ 
 {% endtab %}
 {% endtabs %}
 
-The solution is to call the more idiomatic `pojo.fooBar` getter and setter.
-
-{% tabs bean_2 class=tabs-scala-version %}
-{% tab 'Scala 2' for=bean_2 %}
+In Scala 3, the solution is to call the more idiomatic `pojo.fooBar` getter and setter.
 
-~~~ scala
-val pojo = new Pojo()
-
-pojo.setFooBar("hello")
-
-println(pojo.getFooBar())
-~~~
-{% endtab %}
-{% tab 'Scala 3' for=bean_2 %}
-~~~ scala
+{% highlight diff %}
 val pojo = new Pojo()
 
-pojo.fooBar = "hello"
+-pojo.setFooBar("hello")
++pojo.fooBar = "hello"
 
-println(pojo.fooBar)
-~~~
-{% endtab %}
-{% endtabs %}
+-println(pojo.getFooBar())
++println(pojo.fooBar)
+{% endhighlight %}
 
 ## `=> T` as Type Argument
 
@@ -315,40 +299,31 @@ The solution depends on the situation. In the given example, you can either:
 
 Scala 3 cannot reduce the application of a higher-kinded abstract type member to the wildcard argument.
 
-{% tabs scala-3-wildcard_1 %}
-{% tab 'Scala 3 Only' %}
+{% tabs scala-2-wildcard_1 %}
+{% tab 'Scala 2 Only' %}
 
-For instance, the following example does not compile.
+For instance, the below Scala 2 code would fail to compile in Scala 3:
 
 ~~~ scala
 trait Example {
   type Foo[A]
 
-  def f(foo: Foo[_]): Unit // [E043] Type Error: unreducible application of higher-kinded type Example.this.Foo to wildcard arguments 
+  def f(foo: Foo[_]): Unit // [E043] In Scala 3, Type Error: unreducible application of higher-kinded type Example.this.Foo to wildcard arguments 
 }
 ~~~
 {% endtab %}
 {% endtabs %}
 
 We can fix this by using a type parameter:
 
-{% tabs wildcard_2 class=tabs-scala-version %}
-{% tab 'Scala 2' for=wildcard_2 %}
-
-~~~ scala
-def f(foo: Foo[_]): Unit
-~~~
-{% endtab %}
-{% tab 'Scala 3' for=wildcard_2 %}
-~~~ scala
-def f[A](foo: Foo[A]): Unit
-~~~
-{% endtab %}
-{% endtabs %}
+{% highlight diff %}
+-def f(foo: Foo[_]): Unit
++def f[A](foo: Foo[A]): Unit
+{% endhighlight %}
 
 But this simple solution does not work when `Foo` is itself used as a type argument.
-{% tabs shared-wildcard_3 %}
-{% tab 'Scala 2 and 3' %}
+{% tabs scala-2-wildcard_2 %}
+{% tab 'Scala 2 Only' %}
 ~~~ scala
 def g(foos: Seq[Foo[_]]): Unit
 ~~~
@@ -357,17 +332,9 @@ def g(foos: Seq[Foo[_]]): Unit
 
 In such case, we can use a wrapper class around `Foo`:
 
-{% tabs wildcard_4 class=tabs-scala-version %}
-{% tab 'Scala 2' for=wildcard_4 %}
-~~~ scala
-def g(foos: Seq[Foo[_]]): Unit
-~~~
-{% endtab %}
-{% tab 'Scala 3' for=wildcard_4 %}
-~~~ scala
-class FooWrapper[A](foo: Foo[A])
+{% highlight diff %}
++class FooWrapper[A](foo: Foo[A])
 
-def g(foos: Seq[FooWrapper[_]]): Unit
-~~~
-{% endtab %}
-{% endtabs %}
+-def g(foos: Seq[Foo[_]]): Unit
++def g(foos: Seq[FooWrapper[_]]): Unit
+{% endhighlight %}