Do not enable experimental by default in nightly and snapshot versions

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

@@ -136,8 +136,7 @@ object Feature:
       report.error(
         em"""Experimental $which may only be used under experimental mode:
             |  1. In a definition marked as @experimental
-            |  2. Compiling with the -experimental compiler flag
-            |  3. With a nightly or snapshot version of the compiler$note
+            |  2. Compiling with the -experimental compiler flag$note
           """, srcPos)
 
   private def ccException(sym: Symbol)(using Context): Boolean =
@@ -163,7 +162,7 @@ object Feature:
     do checkExperimentalFeature(s"feature $setting", NoSourcePosition)
 
   def isExperimentalEnabled(using Context): Boolean =
-    (Properties.experimental || ctx.settings.experimental.value) && !ctx.settings.YnoExperimental.value
+    ctx.settings.experimental.value
 
   /** 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

@@ -84,13 +84,8 @@ trait PropertiesTrait {
    */
   val versionString: String = "version " + simpleVersionString
 
-  /** Whether the current version of compiler is experimental
-   *
-   *  1. Snapshot, nightly releases and non-bootstrapped compiler are experimental.
-   *  2. Features supported by experimental versions of the compiler:
-   *     - research plugins
-   */
-  val experimental: Boolean = versionString.contains("SNAPSHOT") || versionString.contains("NIGHTLY") || versionString.contains("nonbootstrapped")
+  /** Whether the current version of supports research plugins */
+  val researchPluginsEnabled: Boolean = versionString.contains("SNAPSHOT") || versionString.contains("NIGHTLY") || versionString.contains("nonbootstrapped")
 
   val copyrightString: String       = scalaPropOrElse("copyright.string", "(c) 2002-2017 LAMP/EPFL")
 

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

@@ -397,7 +397,6 @@ 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.")
   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/plugins/Plugins.scala

@@ -129,7 +129,7 @@ trait Plugins {
     val updatedPlan = Plugins.schedule(plan, pluginPhases)
 
     // add research plugins
-    if Properties.experimental && !ctx.settings.YnoExperimental.value then
+    if Properties.researchPluginsEnabled then
       plugins.collect { case p: ResearchPlugin => p }.foldRight(updatedPlan) {
         (plug, plan) => plug.init(options(plug), plan)
       }

compiler/test/dotty/tools/DottyTest.scala

@@ -40,6 +40,7 @@ trait DottyTest extends ContextEscapeDetection {
   protected def initializeCtx(fc: FreshContext): Unit = {
     fc.setSetting(fc.settings.encoding, "UTF8")
     fc.setSetting(fc.settings.classpath, TestConfiguration.basicClasspath)
+    fc.setSetting(fc.settings.experimental, true)
     fc.setSetting(fc.settings.language, List("experimental.erasedDefinitions"))
     fc.setProperty(ContextDoc, new ContextDocstrings)
   }

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

@@ -29,6 +29,7 @@ class BootstrappedOnlyCompilationTests {
     aggregateTests(
       compileFilesInDir("tests/bench", defaultOptions.without("-Yno-deep-subtypes")),
       compileFilesInDir("tests/pos-macros", defaultOptions.and("-Xcheck-macros")),
+      compileFilesInDir("tests/pos-no-experimental", defaultOptions.without("-experimental")),
     ).checkCompile()
   }
 
@@ -104,8 +105,10 @@ class BootstrappedOnlyCompilationTests {
 
   @Test def negMacros: Unit = {
     implicit val testGroup: TestGroup = TestGroup("compileNegWithCompiler")
-    compileFilesInDir("tests/neg-macros", defaultOptions.and("-Xcheck-macros"))
-      .checkExpectedErrors()
+    aggregateTests(
+      compileFilesInDir("tests/neg-macros", defaultOptions.and("-Xcheck-macros")),
+      compileFilesInDir("tests/neg-no-experimental", defaultOptions.without("-experimental")),
+    ).checkExpectedErrors()
   }
 
   @Test def negWithCompiler: Unit = {

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

@@ -59,7 +59,9 @@ class TastyBootstrapTests {
 
     val lib =
       compileList("lib", librarySources,
-        defaultOptions.and("-Ycheck-reentrant",
+        defaultOptions.and(
+          "-Ycheck-reentrant",
+          "-experimental",
           "-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)

compiler/test/dotty/tools/repl/ReplTest.scala

@@ -104,6 +104,6 @@ extends ReplDriver(options, new PrintStream(out, true, StandardCharsets.UTF_8.na
   }
 
 object ReplTest:
-  val commonOptions = Array("-color:never", "-language:experimental.erasedDefinitions", "-pagewidth", "80")
+  val commonOptions = Array("-color:never", "-pagewidth", "80")
   val defaultOptions = commonOptions ++ Array("-classpath", TestConfiguration.basicClasspath)
   lazy val withStagingOptions = commonOptions ++ Array("-classpath", TestConfiguration.withStagingClasspath)

compiler/test/dotty/tools/repl/ScriptedTests.scala

@@ -6,7 +6,7 @@ import org.junit.Test
 import org.junit.experimental.categories.Category
 
 /** Runs all tests contained in `compiler/test-resources/repl/` */
-class ScriptedTests extends ReplTest {
+class ScriptedTests extends ReplTest(ScriptedTests.options) {
 
   @Test def replTests = scripts("/repl").foreach(testFile)
 
@@ -17,4 +17,5 @@ class ScriptedTests extends ReplTest {
 }
 
 object ScriptedTests {
+  val options = Array("-experimental", "-language:experimental.erasedDefinitions") ++ ReplTest.defaultOptions
 }

compiler/test/dotty/tools/vulpix/TestConfiguration.scala

@@ -65,7 +65,7 @@ object TestConfiguration {
 
   val yCheckOptions = Array("-Ycheck:all")
 
-  val commonOptions = Array("-indent") ++ checkOptions ++ noCheckOptions ++ yCheckOptions
+  val commonOptions = Array("-indent", "-experimental") ++ checkOptions ++ noCheckOptions ++ yCheckOptions
   val defaultOptions = TestFlags(basicClasspath, commonOptions)
   val unindentOptions = TestFlags(basicClasspath, Array("-no-indent") ++ checkOptions ++ noCheckOptions ++ yCheckOptions)
   val withCompilerOptions =

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

@@ -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.
 

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:
@@ -265,9 +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.
 
 ## Experimental inheritance

project/Build.scala

@@ -1675,7 +1675,10 @@ object Build {
 
   lazy val `scaladoc-testcases` = project.in(file("scaladoc-testcases")).
     dependsOn(`scala3-compiler-bootstrapped`).
-    settings(commonBootstrappedSettings)
+    settings(commonBootstrappedSettings).
+    settings(
+      scalacOptions += "-experimental",
+    )
 
 
   /**
@@ -1758,6 +1761,7 @@ object Build {
       SourceLinksIntegrationTest / test:= ((SourceLinksIntegrationTest / test) dependsOn generateScalaDocumentation.toTask("")).value,
     ).
     settings(
+      scalacOptions += "-experimental", // FIXME scaladoc should not use exprimental APIs
       Compile / resourceGenerators ++= Seq(
         generateStaticAssetsTask.taskValue,
         bundleCSS.taskValue
@@ -2155,9 +2159,6 @@ 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) {

staging/src/scala/quoted/staging/QuoteDriver.scala

@@ -37,7 +37,10 @@ private class QuoteDriver(appClassloader: ClassLoader) extends Driver:
     val ctx = {
       val ctx0 = QuotesCache.init(initCtx.fresh)
       val ctx1 = setup(settings.compilerArgs.toArray :+ "dummy.scala", ctx0).get._2
-      setCompilerSettings(ctx1.fresh.setSetting(ctx1.settings.outputDir, outDir), settings)
+      val ctx2 = ctx1.fresh
+      ctx2.setSetting(ctx1.settings.outputDir, outDir)
+      ctx2.setSetting(ctx1.settings.experimental, true)
+      setCompilerSettings(ctx2, settings)
     }
 
     new QuoteCompiler().newRun(ctx).compileExpr(exprBuilder) match

tests/neg-macros/i18677-a.check

@@ -1,16 +1,16 @@
 
--- Error: tests/neg-macros/i18677-a/Test_2.scala:4:6 -------------------------------------------------------------------
-3 |@extendFoo
-4 |class AFoo // error
+-- Error: tests/neg-macros/i18677-a/Test_2.scala:2:6 -------------------------------------------------------------------
+1 |@extendFoo
+2 |class AFoo // error
   |^
   |Malformed tree was found while expanding macro with -Xcheck-macros.
   |The tree does not conform to the compiler's tree invariants.
   |
   |Macro was:
-  |@scala.annotation.internal.SourceFile("tests/neg-macros/i18677-a/Test_2.scala") @extendFoo class AFoo()
+  |@scala.annotation.internal.SourceFile("tests/neg-macros/i18677-a/Test_2.scala") @scala.annotation.experimental @extendFoo class AFoo()
   |
   |The macro returned:
-  |@scala.annotation.internal.SourceFile("tests/neg-macros/i18677-a/Test_2.scala") @extendFoo class AFoo() extends Foo
+  |@scala.annotation.internal.SourceFile("tests/neg-macros/i18677-a/Test_2.scala") @scala.annotation.experimental @extendFoo class AFoo() extends Foo
   |
   |Error:
   |assertion failed: Parents of class symbol differs from the parents in the tree for class AFoo

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

@@ -1,5 +1,3 @@
-//> using -expermiental
-
 import annotation.MacroAnnotation
 import quoted.*
 
@@ -15,4 +13,4 @@ class extendFoo extends MacroAnnotation :
                 newTree :: Nil
             case _ =>
                 report.error("@extendFoo can only annotate class definitions")
-                tree :: Nil
+                tree :: Nil

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

@@ -1,4 +1,2 @@
-//> using -expermiental
-
 @extendFoo
-class AFoo // error
+class AFoo // error

tests/neg-macros/i18677-b.check

@@ -1,16 +1,16 @@
 
--- Error: tests/neg-macros/i18677-b/Test_2.scala:4:6 -------------------------------------------------------------------
-3 |@extendFoo
-4 |class AFoo // error
+-- Error: tests/neg-macros/i18677-b/Test_2.scala:2:6 -------------------------------------------------------------------
+1 |@extendFoo
+2 |class AFoo // error
   |^
   |Malformed tree was found while expanding macro with -Xcheck-macros.
   |The tree does not conform to the compiler's tree invariants.
   |
   |Macro was:
-  |@scala.annotation.internal.SourceFile("tests/neg-macros/i18677-b/Test_2.scala") @extendFoo class AFoo()
+  |@scala.annotation.internal.SourceFile("tests/neg-macros/i18677-b/Test_2.scala") @scala.annotation.experimental @extendFoo class AFoo()
   |
   |The macro returned:
-  |@scala.annotation.internal.SourceFile("tests/neg-macros/i18677-b/Test_2.scala") @extendFoo class AFoo() extends Foo
+  |@scala.annotation.internal.SourceFile("tests/neg-macros/i18677-b/Test_2.scala") @scala.annotation.experimental @extendFoo class AFoo() extends Foo
   |
   |Error:
   |assertion failed: Parents of class symbol differs from the parents in the tree for class AFoo

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

@@ -1,5 +1,3 @@
-//> using -expermiental
-
 import annotation.MacroAnnotation
 import quoted.*
 
@@ -15,4 +13,4 @@ class extendFoo extends MacroAnnotation :
                 newTree :: Nil
             case _ =>
                 report.error("@extendFoo can only annotate class definitions")
-                tree :: Nil
+                tree :: Nil

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

@@ -1,4 +1,2 @@
-//> using -expermiental
-
 @extendFoo
-class AFoo // error
+class AFoo // error

tests/run-macros/term-show.check

@@ -10,7 +10,7 @@
   }
   ()
 }
-@scala.annotation.internal.SourceFile("tests/run-macros/term-show/Test_2.scala") trait A() extends java.lang.Object {
+@scala.annotation.internal.SourceFile("tests/run-macros/term-show/Test_2.scala") @scala.annotation.experimental trait A() extends java.lang.Object {
   def imp(x: scala.Int)(implicit str: scala.Predef.String): scala.Int
   def use(`x₂`: scala.Int)(using `str₂`: scala.Predef.String): scala.Int
   def era(`x₃`: scala.Int)(erased `str₃`: scala.Predef.String): scala.Int