Disable experimental on nightly/snapshot build without -experimental

Author: nicolasstucki

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

@@ -135,10 +135,9 @@ object Feature:
   def checkExperimentalFeature(which: String, srcPos: SrcPos, note: => String = "")(using Context) =
     if !isExperimentalEnabled then
       report.error(
-        em"""Experimental $which may only be used under experimental mode:
+        em"""$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 =
@@ -153,18 +152,18 @@ object Feature:
       if !ccException(experimentalSym) then
         val symMsg =
           if experimentalSym.exists
-          then i"$experimentalSym is marked @experimental"
-          else i"$sym inherits @experimental"
-        report.error(em"$symMsg and therefore may only be used in an experimental scope.", srcPos)
+          then i"$experimentalSym is marked @experimental, it"
+          else i"$sym inherits @experimental, it"
+        checkExperimentalFeature(symMsg, srcPos)
 
-  /** Check that experimental compiler options are only set for snapshot or nightly compiler versions. */
+  /** Check that experimental compiler options are only set with `-experimental`. */
   def checkExperimentalSettings(using Context): Unit =
     for setting <- ctx.settings.language.value
         if setting.startsWith("experimental.") && setting != "experimental.macros"
-    do checkExperimentalFeature(s"feature $setting", NoSourcePosition)
+    do checkExperimentalFeature(s"Experimental 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

@@ -84,14 +84,6 @@ 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")
-
   val copyrightString: String       = scalaPropOrElse("copyright.string", "(c) 2002-2017 LAMP/EPFL")
 
   /** This is the encoding to use reading in source files, overridden with -encoding

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

@@ -368,7 +368,6 @@ 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 Yscala2Stdlib: Setting[Boolean] = BooleanSetting("-Yscala2-stdlib", "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/typer/Checking.scala

@@ -805,15 +805,15 @@ object Checking {
         case Some(nme.experimental)
         if !ctx.owner.isInExperimentalScope && !selectors.forall(isAllowedImport) =>
           def check(stable: => String) =
-            Feature.checkExperimentalFeature("features", imp.srcPos,
+            Feature.checkExperimentalFeature("Experimental features", imp.srcPos,
               s"\n\nNote: the scope enclosing the import is not considered experimental because it contains the\nnon-experimental $stable")
           if ctx.owner.is(Package) then
             // allow top-level experimental imports if all definitions are @experimental
             nonExperimentalStat(trees) match
               case EmptyTree =>
               case tree: MemberDef => check(i"${tree.symbol}")
               case tree => check(i"expression ${tree}")
-          else Feature.checkExperimentalFeature("features", imp.srcPos)
+          else Feature.checkExperimentalFeature("Experimental features", imp.srcPos)
         case _ =>
   end checkExperimentalImports
 }

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

@@ -173,7 +173,7 @@ trait QuotesAndSplices {
     getQuotedPatternTypeVariable(tree.name.asTypeName) match
       case Some(typeSym) =>
         checkExperimentalFeature(
-          "support for multiple references to the same type (without backticks) in quoted type patterns (SIP-53)",
+          "Experimental support for multiple references to the same type (without backticks) in quoted type patterns (SIP-53)",
           tree.srcPos,
           "\n\nSIP-53: https://docs.scala-lang.org/sips/quote-pattern-type-variable-syntax.html")
         warnOnInferredBounds(typeSym)
@@ -225,7 +225,7 @@ trait QuotesAndSplices {
 
     if quoted.isType && untpdTypeVariables.nonEmpty then
       checkExperimentalFeature(
-        "explicit type variable declarations quoted type patterns (SIP-53)",
+        "Experimental explicit type variable declarations quoted type patterns (SIP-53)",
         untpdTypeVariables.head.srcPos,
         "\n\nSIP-53: https://docs.scala-lang.org/sips/quote-pattern-type-variable-syntax.html")
 

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

@@ -191,7 +191,7 @@ class BootstrappedOnlyCompilationTests {
       val targets = dirs.map { dir =>
         val compileDir = createOutputDirsForDir(dir, sourceDir, outDir)
         Files.copy(dir.toPath.resolve(pluginFile), compileDir.toPath.resolve(pluginFile), StandardCopyOption.REPLACE_EXISTING)
-        val flags = TestFlags(withCompilerClasspath, noCheckOptions).and("-Xplugin:" + compileDir.getAbsolutePath)
+        val flags = TestFlags(withCompilerClasspath, noCheckOptions).and("-Xplugin:" + compileDir.getAbsolutePath).and("-experimental")
         SeparateCompilationSource("testPlugins", dir, flags, compileDir)
       }
 

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

@@ -35,7 +35,7 @@ class CompilationTests {
       compileFilesInDir("tests/pos-special/sourcepath/outer", defaultOptions.and("-sourcepath", "tests/pos-special/sourcepath")),
       compileFile("tests/pos-special/sourcepath/outer/nested/Test4.scala", defaultOptions.and("-sourcepath", "tests/pos-special/sourcepath")),
       compileFilesInDir("tests/pos-scala2", defaultOptions.and("-source", "3.0-migration")),
-      compileFilesInDir("tests/pos-custom-args/captures", defaultOptions.and("-language:experimental.captureChecking")),
+      compileFilesInDir("tests/pos-custom-args/captures", defaultOptions.and("-language:experimental.captureChecking", "-experimental")),
       compileFile("tests/pos-special/utf8encoded.scala", defaultOptions.and("-encoding", "UTF8")),
       compileFile("tests/pos-special/utf16encoded.scala", defaultOptions.and("-encoding", "UTF16")),
       // Run tests for legacy lazy vals
@@ -125,8 +125,9 @@ class CompilationTests {
     aggregateTests(
       compileFilesInDir("tests/neg", defaultOptions),
       compileFilesInDir("tests/neg-deep-subtype", allowDeepSubtypes),
-      compileFilesInDir("tests/neg-custom-args/captures", defaultOptions.and("-language:experimental.captureChecking")),
+      compileFilesInDir("tests/neg-custom-args/captures", defaultOptions.and("-language:experimental.captureChecking", "-experimental")),
       compileFile("tests/neg-custom-args/sourcepath/outer/nested/Test1.scala", defaultOptions.and("-sourcepath", "tests/neg-custom-args/sourcepath")),
+      compileFile("tests/neg-custom-args/experimental-erased.scala", defaultOptions),
       compileDir("tests/neg-custom-args/sourcepath2/hi", defaultOptions.and("-sourcepath", "tests/neg-custom-args/sourcepath2", "-Xfatal-warnings")),
       compileList("duplicate source", List(
         "tests/neg-custom-args/toplevel-samesource/S.scala",
@@ -148,7 +149,7 @@ class CompilationTests {
     aggregateTests(
       compileFilesInDir("tests/run", defaultOptions.and("-Ysafe-init")),
       compileFilesInDir("tests/run-deep-subtype", allowDeepSubtypes),
-      compileFilesInDir("tests/run-custom-args/captures", allowDeepSubtypes.and("-language:experimental.captureChecking")),
+      compileFilesInDir("tests/run-custom-args/captures", allowDeepSubtypes.and("-language:experimental.captureChecking", "-experimental")),
       // Run tests for legacy lazy vals.
       compileFilesInDir("tests/run", defaultOptions.and("-Ysafe-init", "-Ylegacy-lazy-vals", "-Ycheck-constraint-deps"), FileFilter.include(TestSources.runLazyValsAllowlist)),
     ).checkRuns()

docs/_docs/reference/changed-features/compiler-plugins.md

@@ -18,7 +18,7 @@ For experimentation and research, Scala 3 introduces _research plugin_. Research
 are more powerful than Scala 2 analyzer plugins as they let plugin authors customize
 the whole compiler pipeline. One can easily replace the standard typer by a custom one or
 create a parser for a domain-specific language. However, research plugins are only
-enabled with the `-experimental` compiler flag or in nightly/snapshot releases of Scala 3.
+enabled with the `-experimental` compiler flag.
 
 Common plugins that add new phases to the compiler pipeline are called
 _standard plugins_ in Scala 3. In terms of features, they are similar to

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

@@ -265,8 +265,7 @@ 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.
+6. Any code compiled using the `-experimental` compiler flag considered to be in an experimental scope.
 
 In any other situation, a reference to an experimental definition will cause a compilation error.
 

project/Build.scala

@@ -2026,9 +2026,6 @@ 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) {