Merge pull request #13622 from dwijnand/bp/source-3.1

[Backport] Allow -source 3.1 as a version

Author: bishabosha

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

@@ -91,7 +91,7 @@ object Feature:
   def warnOnMigration(msg: Message, pos: SrcPos,
       version: SourceVersion = defaultSourceVersion)(using Context): Boolean =
     if sourceVersion.isMigrating && sourceVersion.stable == version
-       || version == `3.0` && migrateTo3
+       || (version == `3.0` || version == `3.1`) && migrateTo3
     then
       report.migrationWarning(msg, pos)
       true

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

@@ -52,7 +52,7 @@ trait AllScalaSettings extends CommonScalaSettings, VerboseSettings, WarningSett
     // it is otherwise subsumed by -explain, and should be dropped as soon as we can.
   val explain: Setting[Boolean] = BooleanSetting("-explain", "Explain errors in more detail.", aliases = List("--explain"))
   val feature: Setting[Boolean] = BooleanSetting("-feature", "Emit warning and location for usages of features that should be imported explicitly.", aliases = List("--feature"))
-  val source: Setting[String] = ChoiceSetting("-source", "source version", "source version", List("3.0", "future", "3.0-migration", "future-migration"), "3.0", aliases = List("--source"))
+  val source: Setting[String] = ChoiceSetting("-source", "source version", "source version", List("3.0", "3.1", "future", "3.0-migration", "future-migration"), "3.0", aliases = List("--source"))
   val unchecked: Setting[Boolean] = BooleanSetting("-unchecked", "Enable additional warnings where generated code depends on assumptions.", initialValue = true, aliases = List("--unchecked"))
   val uniqid: Setting[Boolean] = BooleanSetting("-uniqid", "Uniquely tag all identifiers in debugging output.", aliases = List("--unique-id"))
   val language: Setting[List[String]] = MultiStringSetting("-language", "feature", "Enable one or more language features.", aliases = List("--language"))

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

@@ -9,7 +9,7 @@ import core.Decorators.{_, given}
 import util.Property
 
 enum SourceVersion:
-  case `3.0-migration`, `3.0`, `future-migration`, `future`
+  case `3.0-migration`, `3.0`, `3.1`, `future-migration`, `future`
 
   val isMigrating: Boolean = toString.endsWith("-migration")
 

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -37,7 +37,7 @@ class CompilationTests {
       compileFilesInDir("tests/pos-special/spec-t5545", defaultOptions),
       compileFilesInDir("tests/pos-special/strawman-collections", allowDeepSubtypes),
       compileFilesInDir("tests/pos-special/isInstanceOf", allowDeepSubtypes.and("-Xfatal-warnings")),
-      compileFilesInDir("tests/new", defaultOptions),
+      compileFilesInDir("tests/new", defaultOptions.and("-source", "3.1")), // just to see whether 3.1 works
       compileFilesInDir("tests/pos-scala2", scala2CompatMode),
       compileFilesInDir("tests/pos-custom-args/erased", defaultOptions.and("-language:experimental.erasedDefinitions")),
       compileFilesInDir("tests/pos", defaultOptions.and("-Ysafe-init")),