chore: rename scala.language.2 to scala.language.2.13

Author: hamzaremmal

compiler/src/dotty/tools/dotc/config/SourceVersion.scala

@@ -17,7 +17,7 @@ enum SourceVersion:
   case `3.7-migration`, `3.7`
   case `3.8-migration`, `3.8`
   // !!! Keep in sync with scala.runtime.stdlibPatches.language !!!
-  case `2`
+  case `2.13`
   case `future-migration`, `future`
 
   case `never`    // needed for MigrationVersion.errorFrom if we never want to issue an error
@@ -40,7 +40,7 @@ enum SourceVersion:
   def enablesNamedTuples = isAtLeast(`3.7`)
   def enablesBetterFors(using Context) = isAtLeast(`3.7`) && isPreviewEnabled
 
-  def isScala2 = this == `2`
+  def isScala2 = this == `2.13`
 
 object SourceVersion extends Property.Key[SourceVersion]:
   def defaultSourceVersion = `3.7`

library/src/scala/runtime/stdLibPatches/language.scala

@@ -222,9 +222,11 @@ object language:
   @compileTimeOnly("`future-migration` can only be used at compile time in import statements")
   object `future-migration`
 
-  /** Set source version to 2 */
-  @compileTimeOnly("`2` can only be used at compile time in import statements")
-  private[scala] object `2`
+  /** Set source version to 2.13. Effectively, this doesn't change the source language,
+   * but rather adapts the generated code as if it was compiled with Scala 2.13
+   */
+  @compileTimeOnly("`2.13` can only be used at compile time in import statements")
+  private[scala] object `2.13`
 
   /** Set source version to 3.0-migration.
     *

project/Build.scala

@@ -1248,7 +1248,7 @@ object Build {
         Seq("-sourcepath", ((Compile/sourceManaged).value / "scala-library-src").toString)
       },
       Compile / doc / scalacOptions += "-Ydocument-synthetic-types",
-      scalacOptions ++= Seq("-source", "2"),
+      scalacOptions ++= Seq("-source", "2.13"),
       scalacOptions += "-Yscala2-unpickler:never",
       scalacOptions += "-Werror:false",
       Compile / compile / logLevel.withRank(KeyRanks.Invisible) := Level.Error,

project/MiMaFilters.scala

@@ -14,8 +14,8 @@ object MiMaFilters {
         ProblemFilters.exclude[FinalClassProblem]("scala.scalajs.runtime.AnonFunctionXXL"),
         ProblemFilters.exclude[DirectMissingMethodProblem]("scala.scalajs.runtime.AnonFunctionXXL.this"),
 
-        ProblemFilters.exclude[MissingFieldProblem]("scala.runtime.stdLibPatches.language.2"),
-        ProblemFilters.exclude[MissingClassProblem]("scala.runtime.stdLibPatches.language$2$"),
+        ProblemFilters.exclude[MissingFieldProblem]("scala.runtime.stdLibPatches.language.2.13"),
+        ProblemFilters.exclude[MissingClassProblem]("scala.runtime.stdLibPatches.language$2.13$"),
       ),
 
       // Additions since last LTS

tests/init-global/pos/scala2-library.scala

@@ -1,5 +1,5 @@
 package scala
 
-import scala.language.`2`
+import scala.language.`2.13`
 
 case class UninitializedFieldError(msg: String) extends RuntimeException(msg)

tests/printing/posttyper/i22533.check

@@ -1,6 +1,6 @@
 [[syntax trees at end of                 posttyper]] // tests/printing/posttyper/i22533.scala
 package scala {
-  import scala.language.2
+  import scala.language.2.13
   @SourceFile("tests/printing/posttyper/i22533.scala") trait A() extends Any {
     override def equals(x: Any): Boolean = ???
     override def hashCode(): Int = ???

tests/printing/posttyper/i22533.scala

@@ -1,6 +1,6 @@
 package scala
 
-import scala.language.`2`
+import scala.language.`2.13`
 
 trait A extends Any:
     override def equals(x: Any): Boolean = ???