Test with -Yno-experimental

Author: liufengyun

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

@@ -31,9 +31,12 @@ object Feature:
 
   /** Experimental features are only enabled for snapshot and nightly compiler versions
    */
-  def checkExperimentalFeature(feature: TermName): Boolean =
+  def experimentalEnabled(using Context): Boolean =
+    Properties.experimental && !ctx.settings.YnoExperimental.value
+
+  def isExperimental(feature: TermName): Boolean =
     feature match
-    case QualifiedName(nme.experimental, _) => Properties.experimental
+    case QualifiedName(nme.experimental, _) => true
     case _ => true
 
   /** Is `feature` enabled by by a command-line setting? The enabling setting is
@@ -68,7 +71,8 @@ object Feature:
    *  Note: Experimental features are only enabled for snapshot and nightly version of compiler.
    */
   def enabled(feature: TermName)(using Context): Boolean =
-    checkExperimentalFeature(feature) && (enabledBySetting(feature) || enabledByImport(feature))
+    (experimentalEnabled || !isExperimental(feature))
+    && (enabledBySetting(feature) || enabledByImport(feature))
 
   /** Is auto-tupling enabled? */
   def autoTuplingEnabled(using Context): Boolean = !enabled(nme.noAutoTupling)
@@ -111,7 +115,7 @@ object Feature:
 
   /** Check that experimental compiler options are only set for snapshot or nightly compiler versions. */
   def checkExperimentalFlags(using Context): Unit =
-    if !Properties.experimental then
+    if !experimentalEnabled then
       val features = ctx.settings.language.value.filter(_.contains(nme.experimental.toString))
       if features.nonEmpty then
         report.error(

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

@@ -215,6 +215,7 @@ class ScalaSettings extends Settings.SettingGroup with CommonScalaSettings {
   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 YprofileEnabled: Setting[Boolean] = BooleanSetting("-Yprofile-enabled", "Enable profiling.")
   val YprofileDestination: Setting[String] = StringSetting("-Yprofile-destination", "file", "Where to send profiling output - specify a file, default is to the console.", "")

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -3036,7 +3036,7 @@ object Parsers {
       val imp = Import(tree, selectors)
       if isLanguageImport(tree) then
         in.languageImportContext = in.languageImportContext.importContext(imp, NoSymbol)
-        if isExperimentalImport(tree) && !Properties.experimental then
+        if isExperimentalImport(tree) && !Feature.experimentalEnabled then
           report.error(Feature.experimentalWarningMessage, imp.srcPos)
         for
           case ImportSelector(id @ Ident(imported), EmptyTree, _) <- selectors

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

@@ -130,6 +130,7 @@ class CompilationTests {
       compileFilesInDir("tests/neg-custom-args/allow-double-bindings", allowDoubleBindings),
       compileFilesInDir("tests/neg-custom-args/allow-deep-subtypes", allowDeepSubtypes),
       compileFilesInDir("tests/neg-custom-args/explicit-nulls", defaultOptions.and("-Yexplicit-nulls")),
+      compileFilesInDir("tests/neg-custom-args/no-experimental", defaultOptions.and("-Yno-experimental")),
       compileDir("tests/neg-custom-args/impl-conv", defaultOptions.and("-Xfatal-warnings", "-feature")),
       compileFile("tests/neg-custom-args/implicit-conversions.scala", defaultOptions.and("-Xfatal-warnings", "-feature")),
       compileFile("tests/neg-custom-args/implicit-conversions-old.scala", defaultOptions.and("-Xfatal-warnings", "-feature")),

tests/neg-custom-args/no-experimental/experimental.scala

@@ -0,0 +1,25 @@
+class Test0 {
+  import language.experimental.namedTypeArguments // error
+  object Foo {
+    inline def f[S, T](x: S): T = ???
+    def g(x: Int) = f[T = Any](x)                 // error
+  }
+}
+
+class Test1 {
+  import language.experimental.erasedDefinitions  // error
+  import scala.compiletime.erasedValue
+  type UnivEq[A]
+  object UnivEq:
+    erased def force[A]: UnivEq[A] = erasedValue  // error // error // error
+    extension [A](erased proof: UnivEq[A])        // error
+      inline def univEq(a: A, b: A): Boolean =
+        a == b
+}
+
+class Test1 {
+  import language.experimental.genericNumberLiterals // error
+  val x: BigInt = 13232202002020202020202
+  val y: BigInt = -0xaabb12345ACF12345AC
+}
+