Eliminate -YerasedTerms

Author: odersky

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

@@ -227,7 +227,6 @@ class ScalaSettings extends Settings.SettingGroup with CommonScalaSettings {
  // Extremely experimental language features
  val YnoKindPolymorphism: Setting[Boolean] = BooleanSetting("-Yno-kind-polymorphism", "Disable kind polymorphism.")
  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("-Ysafe-init", "Ensure safe initialization of objects")
  val YrequireTargetName: Setting[Boolean] = BooleanSetting("-Yrequire-targetName", "Warn if an operator is defined without a @targetName annotation")
 

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

@@ -231,9 +231,7 @@ object Parsers {
  }
 
  extension (td: TokenData = in)
- def isErased: Boolean =
- td.token == ERASED
- || td.isIdent(nme.erased) && featureEnabled(Feature.erasedTerms)
+ def isErased: Boolean = td.isIdent(nme.erased) && featureEnabled(Feature.erasedTerms)
 
 /* ------------- ERROR HANDLING ------------------------------------------- */
 
@@ -2692,7 +2690,6 @@ object Parsers {
  case FINAL => Mod.Final()
  case IMPLICIT => Mod.Implicit()
  case GIVEN => Mod.Given()
- case ERASED => Mod.Erased()
  case LAZY => Mod.Lazy()
  case OVERRIDE => Mod.Override()
  case PRIVATE => Mod.Private()

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

@@ -215,8 +215,7 @@ object Scanners {
  private val commentBuf = CharBuffer()
 
  private def handleMigration(keyword: Token): Token =
- if keyword == ERASED && !ctx.settings.YerasedTerms.value then IDENTIFIER
- else if scala3keywords.contains(keyword) && migrateTo3 then treatAsIdent()
+ if scala3keywords.contains(keyword) && migrateTo3 then treatAsIdent()
  else keyword
 
  private def treatAsIdent(): Token =

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

@@ -95,7 +95,6 @@ abstract class TokensCommon {
  //final val THEN = 60; enter(THEN, "then")
  //final val FORSOME = 61; enter(FORSOME, "forSome") // TODO: deprecate
  //final val ENUM = 62; enter(ENUM, "enum")
- //final val ERASED = 63; enter(ERASED, "erased")
 
  /** special symbols */
  final val COMMA = 70; enter(COMMA, "','")
@@ -181,10 +180,9 @@ object Tokens extends TokensCommon {
  final val THEN = 60; enter(THEN, "then")
  final val FORSOME = 61; enter(FORSOME, "forSome") // TODO: deprecate
  final val ENUM = 62; enter(ENUM, "enum")
- final val ERASED = 63; enter(ERASED, "erased")
- final val GIVEN = 64; enter(GIVEN, "given")
- final val EXPORT = 65; enter(EXPORT, "export")
- final val MACRO = 67; enter(MACRO, "macro") // TODO: remove
+ final val GIVEN = 63; enter(GIVEN, "given")
+ final val EXPORT = 64; enter(EXPORT, "export")
+ final val MACRO = 65; enter(MACRO, "macro") // TODO: remove
 
  /** special symbols */
  final val NEWLINE = 78; enter(NEWLINE, "end of statement", "new line")
@@ -240,8 +238,7 @@ object Tokens extends TokensCommon {
 
  final val defIntroTokens: TokenSet = templateIntroTokens | dclIntroTokens
 
- final val localModifierTokens: TokenSet = BitSet(
- ABSTRACT, FINAL, SEALED, IMPLICIT, LAZY, ERASED)
+ final val localModifierTokens: TokenSet = BitSet(ABSTRACT, FINAL, SEALED, IMPLICIT, LAZY)
 
  final val accessModifierTokens: TokenSet = BitSet(
  PRIVATE, PROTECTED)
@@ -283,11 +280,11 @@ object Tokens extends TokensCommon {
  */
  final val startParamTokens: BitSet = modifierTokens | BitSet(VAL, VAR, AT)
 
- final val scala3keywords = BitSet(ENUM, ERASED, GIVEN)
+ final val scala3keywords = BitSet(ENUM, GIVEN)
 
  final val endMarkerTokens = identifierTokens | BitSet(IF, WHILE, FOR, MATCH, TRY, NEW, THROW, GIVEN, VAL, THIS)
 
  final val skipStopTokens = BitSet(SEMI, NEWLINE, NEWLINES, RBRACE, RPAREN, RBRACKET, OUTDENT)
 
- final val softModifierNames = Set(nme.inline, nme.opaque, nme.open, nme.transparent, nme.infix)
+ final val softModifierNames = Set(nme.inline, nme.opaque, nme.open, nme.transparent, nme.infix, nme.erased)
 }

compiler/test/dotty/tools/DottyTest.scala

@@ -42,7 +42,7 @@ 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.YerasedTerms, true)
+ fc.setSetting(fc.settings.language, List("experimental.erasedTerms"))
  fc.setProperty(ContextDoc, new ContextDocstrings)
  }
 

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

@@ -118,7 +118,7 @@ class BootstrappedOnlyCompilationTests {
  aggregateTests(
  compileFilesInDir("tests/run-macros", defaultOptions.and("-Xcheck-macros")),
  compileFilesInDir("tests/run-custom-args/Yretain-trees", defaultOptions and "-Yretain-trees"),
- compileFilesInDir("tests/run-custom-args/run-macros-erased", defaultOptions.and("-Yerased-terms").and("-Xcheck-macros")),
+ compileFilesInDir("tests/run-custom-args/run-macros-erased", defaultOptions.and("-language:experimental.erasedTerms").and("-Xcheck-macros")),
  )
  }.checkRuns()
 

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

@@ -39,7 +39,7 @@ class CompilationTests {
  compileFilesInDir("tests/pos-special/isInstanceOf", allowDeepSubtypes.and("-Xfatal-warnings")),
  compileFilesInDir("tests/new", defaultOptions),
  compileFilesInDir("tests/pos-scala2", scala2CompatMode),
- compileFilesInDir("tests/pos-custom-args/erased", defaultOptions.and("-Yerased-terms")),
+ compileFilesInDir("tests/pos-custom-args/erased", defaultOptions.and("-language:experimental.erasedTerms")),
  compileFilesInDir("tests/pos", defaultOptions.and("-Ysafe-init")),
  compileFilesInDir("tests/pos-deep-subtype", allowDeepSubtypes),
  compileDir("tests/pos-special/java-param-names", defaultOptions.withJavacOnlyOptions("-parameters")),
@@ -126,7 +126,7 @@ class CompilationTests {
  compileFilesInDir("tests/neg-no-kind-polymorphism", defaultOptions and "-Yno-kind-polymorphism"),
  compileFilesInDir("tests/neg-custom-args/deprecation", defaultOptions.and("-Xfatal-warnings", "-deprecation")),
  compileFilesInDir("tests/neg-custom-args/fatal-warnings", defaultOptions.and("-Xfatal-warnings")),
- compileFilesInDir("tests/neg-custom-args/erased", defaultOptions.and("-Yerased-terms")),
+ compileFilesInDir("tests/neg-custom-args/erased", defaultOptions.and("-language:experimental.erasedTerms")),
  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")),
@@ -165,7 +165,7 @@ class CompilationTests {
  compileDir("tests/neg-custom-args/adhoc-extension", defaultOptions.and("-source", "future", "-feature", "-Xfatal-warnings")),
  compileFile("tests/neg/i7575.scala", defaultOptions.withoutLanguageFeatures.and("-language:_")),
  compileFile("tests/neg-custom-args/kind-projector.scala", defaultOptions.and("-Ykind-projector")),
- compileFile("tests/neg-custom-args/typeclass-derivation2.scala", defaultOptions.and("-Yerased-terms")),
+ compileFile("tests/neg-custom-args/typeclass-derivation2.scala", defaultOptions.and("-language:experimental.erasedTerms")),
  compileFile("tests/neg-custom-args/i5498-postfixOps.scala", defaultOptions withoutLanguageFeature "postfixOps"),
  compileFile("tests/neg-custom-args/deptypes.scala", defaultOptions.and("-language:experimental.dependent")),
  compileFile("tests/neg-custom-args/matchable.scala", defaultOptions.and("-Xfatal-warnings", "-source", "future")),
@@ -189,7 +189,7 @@ class CompilationTests {
  compileFile("tests/run-custom-args/fors.scala", defaultOptions.and("-source", "future")),
  compileFile("tests/run-custom-args/no-useless-forwarders.scala", defaultOptions and "-Xmixin-force-forwarders:false"),
  compileFile("tests/run-custom-args/defaults-serizaliable-no-forwarders.scala", defaultOptions and "-Xmixin-force-forwarders:false"),
- compileFilesInDir("tests/run-custom-args/erased", defaultOptions.and("-Yerased-terms")),
+ compileFilesInDir("tests/run-custom-args/erased", defaultOptions.and("-language:experimental.erasedTerms")),
  compileFilesInDir("tests/run-deep-subtype", allowDeepSubtypes),
  compileFilesInDir("tests/run", defaultOptions.and("-Ysafe-init"))
  ).checkRuns()
@@ -248,7 +248,7 @@ class CompilationTests {
  val lib =
  compileList("lib", librarySources,
  defaultOptions.and("-Ycheck-reentrant",
- "-Yerased-terms", // support declaration of scala.compiletime.erasedValue
+ "-language:experimental.erasedTerms", // support declaration of scala.compiletime.erasedValue
  // "-source", "future", // TODO: re-enable once we allow : @unchecked in pattern definitions. Right now, lots of narrowing pattern definitions fail.
  ))(libGroup)
 

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

@@ -94,6 +94,6 @@ extends ReplDriver(options, new PrintStream(out, true, StandardCharsets.UTF_8.na
 }
 
 object ReplTest:
- val commonOptions = Array("-color:never", "-Yerased-terms", "-pagewidth", "80")
+ val commonOptions = Array("-color:never", "-language:experimental.erasedTerms", "-pagewidth", "80")
  val defaultOptions = commonOptions ++ Array("-classpath", TestConfiguration.basicClasspath)
  lazy val withStagingOptions = commonOptions ++ Array("-classpath", TestConfiguration.withStagingClasspath)

tests/pos/CanThrow.scala

@@ -1,11 +1,13 @@
 package canThrowStrawman
 import language.experimental.erasedTerms
 
-class CanThrow[E <: Throwable]
+class CanThrow[E <: Exception]
 
-infix type throws1[R, E <: Throwable] = (erased CanThrow[E]) ?=> R
+infix type throws[R, E <: Exception] = (erased CanThrow[E]) ?=> R
 
 class Fail extends Exception
 
-def foo(x: Boolean): Int throws1 Fail =
- if x then 1 else throw Fail()
+def raise[E <: Exception](e: E): Nothing throws E = throw e
+
+def foo(x: Boolean): Int throws Fail =
+ if x then 1 else raise(Fail())