Remove -Yscala2-experimental-compat

Author: nicolasstucki

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

@@ -168,7 +168,6 @@ class ScalaSettings extends Settings.SettingGroup {
   val YexplicitNulls: Setting[Boolean] = BooleanSetting("-Yexplicit-nulls", "Make reference types non-nullable. Nullable types can be expressed with unions: e.g. String|Null.")
   val YerasedTerms: Setting[Boolean] = BooleanSetting("-Yerased-terms", "Allows the use of erased terms.")
   val YcheckInit: Setting[Boolean] = BooleanSetting("-Ycheck-init", "Check initialization of objects")
-  val YScala2ExperimentalCompat: Setting[Boolean] = BooleanSetting("-Yscala2-experimental-compat", "Allows Scala 2 macro definitions (no checks performed)")
 
   /** Area-specific debug output */
   val YexplainLowlevel: Setting[Boolean] = BooleanSetting("-Yexplain-lowlevel", "When explaining type errors, show types at a lower level.")

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

@@ -2248,20 +2248,7 @@ object Parsers {
           newExpr()
         case MACRO =>
           val start = in.skipToken()
-          val call = simpleExpr()
-          call match
-            case Ident(name) if name eq nme.??? =>
-              // The standard library uses "macro ???" to denote "fast track" macros
-              // hardcoded in the compiler, don't issue an error for those macros
-              // since we want to be able to compile the standard library.
-              MacroTree(call)
-            case _ if ctx.settings.YScala2ExperimentalCompat.value =>
-              MacroTree(call)
-            case _ =>
-              syntaxError(
-                "Scala 2 macros are not supported, see https://dotty.epfl.ch/docs/reference/dropped-features/macros.html",
-                start)
-              unimplementedExpr
+          MacroTree(simpleExpr())
         case COLONEOL =>
           syntaxError("':' not allowed here")
           in.nextToken()

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

@@ -65,8 +65,6 @@ class CompilationTests extends ParallelTesting {
       compileFile("tests/pos-special/kind-projector.scala", defaultOptions.and("-Ykind-projector")),
       compileFile("tests/run/i5606.scala", defaultOptions.and("-Yretain-trees")),
       compileFile("tests/pos-custom-args/i5498-postfixOps.scala", defaultOptions withoutLanguageFeature "postfixOps"),
-      compileFile("tests/pos-custom-args/scala2-macro-compat-1.scala", defaultOptions.and("-Yscala2-experimental-compat")),
-      compileFile("tests/pos-custom-args/scala2-macro-compat-2.scala", defaultOptions.and("-Yscala2-experimental-compat")),
 
     ).checkCompile()
   }
@@ -141,7 +139,6 @@ class CompilationTests extends ParallelTesting {
       compileFile("tests/neg-custom-args/i3882.scala", allowDeepSubtypes),
       compileFile("tests/neg-custom-args/i4372.scala", allowDeepSubtypes),
       compileFile("tests/neg-custom-args/i1754.scala", allowDeepSubtypes),
-      compileFile("tests/neg-custom-args/scala2-macro-compat-no-scala3-implementation.scala", defaultOptions.and("-Yscala2-experimental-compat")),
       compileFile("tests/neg-custom-args/interop-polytypes.scala", allowDeepSubtypes.and("-Yexplicit-nulls")),
       compileFile("tests/neg-custom-args/conditionalWarnings.scala", allowDeepSubtypes.and("-deprecation").and("-Xfatal-warnings")),
       compileFilesInDir("tests/neg-custom-args/isInstanceOf", allowDeepSubtypes and "-Xfatal-warnings"),

tests/neg-custom-args/scala2-macro-compat-no-scala3-implementation.scala renamed to tests/neg/scala2-macro-compat-no-scala3-implementation.scala

@@ -1,5 +1,3 @@
-
-
 object Macro1 {
   import scala.language.experimental.macros
   def lineNumber: Int = macro LineNumberMacro2.thisLineNumberImpl // error: No Scala 3 implementation found for this Scala 2 macro.