WIP

Author: nicolasstucki

compiler/src/dotty/tools/dotc/Driver.scala

@@ -74,7 +74,6 @@ class Driver {
     val ictx = rootCtx.fresh
     val summary = command.distill(args, ictx.settings)(ictx.settingsState)(using ictx)
     ictx.setSettings(summary.sstate)
-    Feature.checkExperimentalSettings(using ictx)
     MacroClassLoader.init(ictx)
     Positioned.init(using ictx)
 

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

@@ -23,6 +23,7 @@ object Feature:
   private val genericNumberLiterals = experimental("genericNumberLiterals")
   val scala2macros = experimental("macros")
 
+  val mode = experimental("mode")
   val dependent = experimental("dependent")
   val erasedDefinitions = experimental("erasedDefinitions")
   val symbolLiterals = deprecated("symbolLiterals")
@@ -32,6 +33,23 @@ object Feature:
   val pureFunctions = experimental("pureFunctions")
   val captureChecking = experimental("captureChecking")
   val into = experimental("into")
+  val relaxedExtensionImports = experimental("relaxedExtensionImports")
+
+  // TODO compute this list
+  // TODO remove features that do not enable experimental mode
+  val experimentalAutoEnableFeatures: List[TermName] = List(
+    mode,
+    namedTypeArguments,
+    genericNumberLiterals,
+    erasedDefinitions,
+    fewerBraces,
+    saferExceptions,
+    clauseInterleaving,
+    pureFunctions,
+    captureChecking,
+    into,
+    relaxedExtensionImports,
+  )
 
   val globalOnlyImports: Set[TermName] = Set(pureFunctions, captureChecking)
 
@@ -132,14 +150,13 @@ object Feature:
       false
 
   def checkExperimentalFeature(which: String, srcPos: SrcPos, note: => String = "")(using Context) =
-    if !isExperimentalEnabled then
+    if !isExperimentalEnabledBySetting && !isExperimentalEnabledByImport then
       report.error(
         em"""Experimental $which may only be used under experimental mode:
             |  1. in a definition marked as @experimental, or
             |  2. an experimental feature is imported in at the package level, or
-            |  3. compiling with the -experimental compiler flag, or
-            |  4. with a nightly or snapshot version of the compiler.$note
-          """, srcPos)
+            |  3. compiling with the -experimental compiler flag.$note
+            |""", srcPos)
 
   private def ccException(sym: Symbol)(using Context): Boolean =
     ccEnabled && defn.ccExperimental.contains(sym)
@@ -156,14 +173,12 @@ object Feature:
         else i"$sym inherits @experimental"
       checkExperimentalFeature("definition", srcPos, s"\n\n$note")
 
-  /** Check that experimental compiler options are only set for snapshot or nightly compiler versions. */
-  def checkExperimentalSettings(using Context): Unit =
-    for setting <- ctx.settings.language.value
-        if setting.startsWith("experimental.") && setting != "experimental.macros"
-    do checkExperimentalFeature(s"feature $setting", NoSourcePosition)
+  def isExperimentalEnabledBySetting(using Context): Boolean =
+    ctx.settings.experimental.value ||
+    experimentalAutoEnableFeatures.exists(enabledBySetting)
 
-  def isExperimentalEnabled(using Context): Boolean =
-    (Properties.unstableExperimentalEnabled && !ctx.settings.YnoExperimental.value) || ctx.settings.experimental.value
+  def isExperimentalEnabledByImport(using Context): Boolean =
+    experimentalAutoEnableFeatures.exists(enabledByImport)
 
   /** Handle language import `import language.<prefix>.<imported>` if it is one
    *  of the global imports `pureFunctions` or `captureChecking`. In this case

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

@@ -84,12 +84,6 @@ trait PropertiesTrait {
    */
   val versionString: String = "version " + simpleVersionString
 
-  /** Whether the current version of compiler is experimental
-   *
-   *  Snapshot, nightly releases and non-bootstrapped compiler are experimental.
-   */
-  val unstableExperimentalEnabled: Boolean = versionString.contains("SNAPSHOT") || versionString.contains("NIGHTLY") || versionString.contains("nonbootstrapped")
-
   /** Whether the current version of compiler supports research plugins. */
   val researchPluginEnabled: Boolean = versionString.contains("SNAPSHOT") || versionString.contains("NIGHTLY") || versionString.contains("nonbootstrapped")
 

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

@@ -399,7 +399,6 @@ private sealed trait YSettings:
   val YretainTrees: Setting[Boolean] = BooleanSetting("-Yretain-trees", "Retain trees for top-level classes, accessible from ClassSymbol#tree")
   val YshowTreeIds: Setting[Boolean] = BooleanSetting("-Yshow-tree-ids", "Uniquely tag all tree nodes in debugging output.")
   val YfromTastyIgnoreList: Setting[List[String]] = MultiStringSetting("-Yfrom-tasty-ignore-list", "file", "List of `tasty` files in jar files that will not be loaded when using -from-tasty.")
-  val YnoExperimental: Setting[Boolean] = BooleanSetting("-Yno-experimental", "Disable experimental language features by default in NIGHTLY/SNAPSHOT versions of the compiler.")
   val YlegacyLazyVals: Setting[Boolean] = BooleanSetting("-Ylegacy-lazy-vals", "Use legacy (pre 3.3.0) implementation of lazy vals.")
   val YcompileScala2Library: Setting[Boolean] = BooleanSetting("-Ycompile-scala2-library", "Used when compiling the Scala 2 standard library.")
   val YoutputOnlyTasty: Setting[Boolean] = BooleanSetting("-Youtput-only-tasty", "Used to only generate the TASTy file without the classfiles")

compiler/src/dotty/tools/dotc/transform/PostTyper.scala

@@ -513,8 +513,8 @@ class PostTyper extends MacroTransform with InfoTransformer { thisPhase =>
       }
 
     override def transformStats[T](trees: List[Tree], exprOwner: Symbol, wrapResult: List[Tree] => Context ?=> T)(using Context): T =
-      try super.transformStats(trees, exprOwner, wrapResult)
-      finally Checking.checkExperimentalImports(trees)
+      Checking.checkExperimentalImports(trees)
+      super.transformStats(trees, exprOwner, wrapResult)
 
     /** Transforms the rhs tree into a its default tree if it is in an `erased` val/def.
      *  Performed to shrink the tree that is known to be erased later.
@@ -549,7 +549,7 @@ class PostTyper extends MacroTransform with InfoTransformer { thisPhase =>
         !sym.is(Package) && !sym.name.isPackageObjectName &&
         (sym.owner.is(Package) || (sym.owner.isPackageObject && !sym.isConstructor))
       if !sym.hasAnnotation(defn.ExperimentalAnnot)
-        && (ctx.settings.experimental.value && isTopLevelDefinitionInSource(sym))
+        && (Feature.isExperimentalEnabledBySetting && isTopLevelDefinitionInSource(sym))
         || (sym.is(Module) && sym.companionClass.hasAnnotation(defn.ExperimentalAnnot))
       then
         sym.addAnnotation(Annotation(defn.ExperimentalAnnot, sym.span))

compiler/src/dotty/tools/dotc/typer/Checking.scala

@@ -827,7 +827,7 @@ object Checking {
       def isAllowedImport(sel: untpd.ImportSelector) =
         val name = Feature.experimental(sel.name)
         name == Feature.scala2macros
-        || name == Feature.erasedDefinitions
+        // || name == Feature.erasedDefinitions
         || name == Feature.captureChecking
 
       languageImport(qual) match
@@ -836,7 +836,7 @@ object Checking {
           def check(stable: => String) =
             Feature.checkExperimentalFeature("features", imp.srcPos,
               s"\n\nNote: the scope enclosing the import is not considered experimental because it contains the\nnon-experimental $stable")
-          if ctx.owner.is(Package) then
+          if ctx.owner.is(Package) || ctx.owner.name.startsWith(str.REPL_SESSION_LINE) then
             // mark all top-level definitions as @experimental
             for tree <- nonExperimentalStats(trees) do
               tree match
@@ -847,7 +847,7 @@ object Checking {
                     sym.addAnnotation(Annotations.Annotation(defn.ExperimentalAnnot, sym.span))
                 case tree =>
                   check(i"expression ${tree}")
-          else Feature.checkExperimentalFeature("features", imp.srcPos)
+          else Feature.checkExperimentalFeature("feature local import", imp.srcPos)
         case _ =>
   end checkExperimentalImports
 

compiler/src/dotty/tools/dotc/typer/CrossVersionChecks.scala

@@ -172,12 +172,14 @@ class CrossVersionChecks extends MiniPhase:
   }
 
   override def transformOther(tree: Tree)(using Context): Tree =
-    tree.foreachSubTree { // Find references in type trees and imports
-      case tree: Ident => transformIdent(tree)
-      case tree: Select => transformSelect(tree)
-      case tree: TypeTree => transformTypeTree(tree)
-      case _ =>
-    }
+    val inPackage = ctx.owner.is(Package) || ctx.owner.isPackageObject
+    if !(inPackage && tree.isInstanceOf[ImportOrExport] && Feature.isExperimentalEnabledByImport) then
+      tree.foreachSubTree { // Find references in type trees and imports
+        case tree: Ident => transformIdent(tree)
+        case tree: Select => transformSelect(tree)
+        case tree: TypeTree => transformTypeTree(tree)
+        case _ =>
+      }
     tree
 
 end CrossVersionChecks

compiler/test/dotty/tools/backend/jvm/PublicInBinaryTests.scala

@@ -42,7 +42,6 @@ class PublicInBinaryTests extends DottyBytecodeTest {
   override def initCtx =
     val ctx0 = super.initCtx
     ctx0.setSetting(ctx0.settings.experimental, true)
-    ctx0.setSetting(ctx0.settings.YnoExperimental, true)
 
   @Test
   def publicInBinaryDef(): Unit = {

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

@@ -60,7 +60,6 @@ class TastyBootstrapTests {
     val lib =
       compileList("lib", librarySources,
         defaultOptions.and("-Ycheck-reentrant",
-          "-language:experimental.erasedDefinitions", // support declaration of scala.compiletime.erasedValue
           //  "-source", "future",  // TODO: re-enable once library uses updated syntax for vararg splices, wildcard imports, and import renaming
           ))(libGroup)
 

docs/_docs/reference/other-new-features/experimental-defs.md

@@ -267,9 +267,6 @@ Experimental definitions can only be referenced in an experimental scope. Experi
 
 6. An experimental language feature is imported in at the package level
 
-7. Any code compiled using a [_Nightly_](https://search.maven.org/artifact/org.scala-lang/scala3-compiler_3) or _Snapshot_ version of the compiler is considered to be in an experimental scope.
-Can use the `-Yno-experimental` compiler flag to disable it and run as a proper release.
-
 In any other situation, a reference to an experimental definition will cause a compilation error.
 
 ## Experimental overriding

docs/_spec/TODOreference/other-new-features/experimental-defs.md

@@ -216,7 +216,7 @@ Experimental definitions can only be referenced in an experimental scope. Experi
 
    <details>
    <summary>Example 1</summary>
-   
+
    ```scala
    import scala.annotation.experimental
 
@@ -242,7 +242,7 @@ Experimental definitions can only be referenced in an experimental scope. Experi
      }
    }
    ```
-   
+
    </details>
 
 5. Annotations of an experimental definition are in experimental scopes. Examples:
@@ -265,8 +265,6 @@ Experimental definitions can only be referenced in an experimental scope. Experi
 
    </details>
 
-6. Any code compiled using a [_Nightly_](https://search.maven.org/artifact/org.scala-lang/scala3-compiler_3) or _Snapshot_ version of the compiler is considered to be in an experimental scope.
-Can use the `-Yno-experimental` compiler flag to disable it and run as a proper release.
 
 In any other situation, a reference to an experimental definition will cause a compilation error.
 

project/Build.scala

@@ -1759,6 +1759,9 @@ object Build {
       SourceLinksIntegrationTest / scalaSource := baseDirectory.value / "test-source-links",
       SourceLinksIntegrationTest / test:= ((SourceLinksIntegrationTest / test) dependsOn generateScalaDocumentation.toTask("")).value,
     ).
+    settings(
+      scalacOptions += "-experimental" // workaround use of experimental .info in Scaladoc2AnchorCreator
+    ).
     settings(
       Compile / resourceGenerators ++= Seq(
         generateStaticAssetsTask.taskValue,
@@ -2167,9 +2170,6 @@ object Build {
           settings(
             versionScheme := Some("semver-spec"),
             libraryDependencies += "org.scala-lang" % "scala-library" % stdlibVersion,
-            // Make sure we do not refer to experimental features outside an experimental scope.
-            // In other words, disable NIGHTLY/SNAPSHOT experimental scope.
-            scalacOptions += "-Yno-experimental",
           ).
           settings(dottyLibrarySettings)
       if (mode == Bootstrapped) {

scaladoc-testcases/src/tests/hugetype.scala

@@ -30,7 +30,7 @@ trait E:
   @deprecated
   protected implicit def same[A](a: A): A
 
-trait XD extends E:
+@experimental trait XD extends E:
   /**
    * Some important information :o
    *

scaladoc-testcases/src/tests/methodsAndConstructors.scala

@@ -1,5 +1,7 @@
 package tests.methodsAndConstructors
 
+import scala.language.experimental.clauseInterleaving
+
 class A
 class B extends A
 class C
@@ -60,8 +62,6 @@ class Methods:
  def withImplicitParam2(v: String)(implicit ab: Double, a: Int, b: String): String
  = ???
 
- import scala.language.experimental.clauseInterleaving
-
  def clauseInterleaving[T](x: T)[U](y: U)(using (T, U)): (T, U)
  = ???
 

scaladoc/src/dotty/tools/scaladoc/snippets/SnippetCompiler.scala

@@ -27,6 +27,7 @@ class SnippetCompiler(
   object SnippetDriver extends Driver:
     val currentCtx =
       val rootCtx = initCtx.fresh.addMode(Mode.ReadPositions).addMode(Mode.Interactive)
+      rootCtx.setSetting(rootCtx.settings.experimental, true)
       rootCtx.setSetting(rootCtx.settings.YretainTrees, true)
       rootCtx.setSetting(rootCtx.settings.YcookComments, true)
       rootCtx.setSetting(rootCtx.settings.YreadComments, true)

tests/init-global/pos/global-region1.scala

@@ -1,3 +1,5 @@
+//> using options -experimental
+
 import scala.annotation.init.region
 
 trait B { def foo(): Int }

tests/init-global/warn/i18628_3.scala

@@ -1,3 +1,5 @@
+//> using options -experimental
+
 import scala.annotation.init.widen
 
 object Test:

tests/neg-macros/i18677-a/Macro_1.scala

@@ -1,4 +1,4 @@
-//> using options -experimental -Yno-experimental
+//> using options -experimental
 
 import annotation.MacroAnnotation
 import quoted.*

tests/neg-macros/i18677-a/Test_2.scala

@@ -1,4 +1,4 @@
-//> using options -experimental -Yno-experimental
+//> using options -experimental
 
 @extendFoo
 class AFoo // error

tests/neg-macros/i18677-b/Macro_1.scala

@@ -1,4 +1,4 @@
-//> using options -experimental -Yno-experimental
+//> using options -experimental
 
 import annotation.MacroAnnotation
 import quoted.*

tests/neg-macros/i18677-b/Test_2.scala

@@ -1,4 +1,4 @@
-//> using options -experimental -Yno-experimental
+//> using options -experimental
 
 @extendFoo
 class AFoo // error

tests/neg-macros/i19842/Macro.scala

@@ -1,3 +1,4 @@
+//> using options -experimental
 
 import scala.annotation.{experimental, targetName}
 import scala.quoted.*

tests/neg-macros/macro-experimental.scala

@@ -1,5 +1,3 @@
-//> using options -Yno-experimental
-
 import scala.quoted.*
 import scala.annotation.experimental
 

tests/neg-macros/newClassExtendsNoParents/Macro_1.scala

@@ -1,4 +1,4 @@
-//> using options -experimental -Yno-experimental
+//> using options -experimental
 
 import scala.quoted.*
 

tests/neg-macros/newClassExtendsNoParents/Test_2.scala

@@ -1,3 +1,3 @@
-//> using options -experimental -Yno-experimental
+//> using options -experimental
 
 def test: Any = makeClass("foo") // error

tests/neg-macros/newClassExtendsOnlyTrait/Macro_1.scala

@@ -1,4 +1,4 @@
-//> using options -experimental -Yno-experimental
+//> using options -experimental
 
 import scala.quoted.*
 

tests/neg-macros/newClassExtendsOnlyTrait/Test_2.scala

@@ -1,3 +1,3 @@
-//> using options -experimental -Yno-experimental
+//> using options -experimental
 
 def test: Foo = makeClass("foo") // error

tests/neg/14034.scala

@@ -1,5 +1,3 @@
-//> using options -Yno-experimental
-
 import annotation.experimental
 
 @experimental trait Exp

tests/neg/expeimental-flag-with-lang-feature-1.scala

@@ -1,5 +1,3 @@
-//> using options -Yno-experimental
-
 import scala.annotation.experimental
 
 class Foo:

tests/neg/expeimental-flag.scala

@@ -1,5 +1,3 @@
-//> using options -Yno-experimental
-
 class Test7 {
   import scala.language.experimental
   import experimental.genericNumberLiterals // error: no aliases can be used to refer to a language import

tests/neg/experimental-2.scala

@@ -1,5 +1,3 @@
-//> using options -Yno-experimental
-
 import annotation.experimental
 
 @experimental
@@ -14,7 +12,7 @@ object Object2:
   import language.experimental.fewerBraces // error
   import language.experimental.namedTypeArguments // error
   import language.experimental.genericNumberLiterals // error
-  import language.experimental.erasedDefinitions
+  import language.experimental.erasedDefinitions // error
   erased def f = 1
 
 @experimental
@@ -29,7 +27,7 @@ object Class2:
   import language.experimental.fewerBraces // error
   import language.experimental.namedTypeArguments // error
   import language.experimental.genericNumberLiterals // error
-  import language.experimental.erasedDefinitions
+  import language.experimental.erasedDefinitions // error
   erased def f = 1
 
 @experimental
@@ -44,5 +42,5 @@ def fun2 =
   import language.experimental.fewerBraces // error
   import language.experimental.namedTypeArguments // error
   import language.experimental.genericNumberLiterals // error
-  import language.experimental.erasedDefinitions
+  import language.experimental.erasedDefinitions // error
   erased def f = 1