Emit "deprecated" bytecode attribute

compiler/src/dotty/tools/dotc/core/Annotations.scala

@@ -206,33 +206,6 @@ object Annotations {
     Annotation(defn.ThrowsAnnot.typeRef.appliedTo(tref), Ident(tref))
   }
 
-  /** A decorator that provides queries for specific annotations
-   *  of a symbol.
-   */
-  implicit class AnnotInfo(val sym: Symbol) extends AnyVal {
-
-    def deprecationMessage(using Context): Option[String] =
-      for {
-        annot <- sym.getAnnotation(defn.DeprecatedAnnot)
-        arg <- annot.argumentConstant(0)
-      }
-      yield arg.stringValue
-
-    def migrationVersion(using Context): Option[Try[ScalaVersion]] =
-      for {
-        annot <- sym.getAnnotation(defn.MigrationAnnot)
-        arg <- annot.argumentConstant(1)
-      }
-      yield ScalaVersion.parse(arg.stringValue)
-
-    def migrationMessage(using Context): Option[Try[ScalaVersion]] =
-      for {
-        annot <- sym.getAnnotation(defn.MigrationAnnot)
-        arg <- annot.argumentConstant(0)
-      }
-      yield ScalaVersion.parse(arg.stringValue)
-  }
-
   /** Extracts the type of the thrown exception from an annotation.
    *
    *  Supports both "old-style" `@throws(classOf[Exception])`

compiler/src/dotty/tools/dotc/reporting/messages.scala

@@ -1925,9 +1925,9 @@ object messages {
     def explain = "A sealed class or trait can only be extended in the same file as its declaration"
   }
 
-  class SymbolHasUnparsableVersionNumber(symbol: Symbol, migrationVersion: String)(using Context)
+  class SymbolHasUnparsableVersionNumber(symbol: Symbol, errorMessage: String)(using Context)
   extends SyntaxMsg(SymbolHasUnparsableVersionNumberID) {
-    def msg = em"${symbol.showLocated} has an unparsable version number: $migrationVersion"
+    def msg = em"${symbol.showLocated} has an unparsable version number: $errorMessage"
     def explain =
       em"""The ${symbol.showLocated} is marked with ${hl("@migration")} indicating it has changed semantics
           |between versions and the ${hl("-Xmigration")} settings is used to warn about constructs
@@ -1940,11 +1940,10 @@ object messages {
     migrationMessage: String
   )(using Context) extends SyntaxMsg(SymbolChangedSemanticsInVersionID) {
     def msg = em"${symbol.showLocated} has changed semantics in version $migrationVersion: $migrationMessage"
-    def explain = {
+    def explain =
       em"""The ${symbol.showLocated} is marked with ${hl("@migration")} indicating it has changed semantics
           |between versions and the ${hl("-Xmigration")} settings is used to warn about constructs
           |whose behavior may have changed since version change."""
-    }
   }
 
   class UnableToEmitSwitch(tooFewCases: Boolean)(using Context)

compiler/src/dotty/tools/dotc/transform/Memoize.scala

@@ -96,10 +96,12 @@ class Memoize extends MiniPhase with IdentityDenotTransformer { thisPhase =>
         case _ => ()
       }
 
-    def removeAnnotations(denot: SymDenotation): Unit =
+    def removeUnwantedAnnotations(denot: SymDenotation): Unit =
       if (sym.annotations.nonEmpty) {
         val cpy = sym.copySymDenotation()
-        cpy.annotations = Nil
+        // Keep @deprecated annotation so that accessors can
+        // be marked as deprecated in the bytecode
+        cpy.filterAnnotations(_.matches(defn.DeprecatedAnnot))
         cpy.installAfter(thisPhase)
       }
 
@@ -135,7 +137,7 @@ class Memoize extends MiniPhase with IdentityDenotTransformer { thisPhase =>
           else transformFollowingDeep(ref(field))(using ctx.withOwner(sym))
         val getterDef = cpy.DefDef(tree)(rhs = getterRhs)
         addAnnotations(fieldDef.denot)
-        removeAnnotations(sym)
+        removeUnwantedAnnotations(sym)
         Thicket(fieldDef, getterDef)
       }
       else if (sym.isSetter) {
@@ -145,7 +147,7 @@ class Memoize extends MiniPhase with IdentityDenotTransformer { thisPhase =>
           if (isErasableBottomField(tree.vparamss.head.head.tpt.tpe.classSymbol)) Literal(Constant(()))
           else Assign(ref(field), adaptToField(ref(tree.vparamss.head.head.symbol)))
         val setterDef = cpy.DefDef(tree)(rhs = transformFollowingDeep(initializer)(using ctx.withOwner(sym)))
-        removeAnnotations(sym)
+        removeUnwantedAnnotations(sym)
         setterDef
       }
       else tree // curiously, some accessors from Scala2 have ' ' suffixes. They count as

compiler/test/dotty/tools/backend/jvm/DottyBytecodeTests.scala

@@ -953,6 +953,12 @@ class TestBCode extends DottyBytecodeTest {
     val code =
       """@deprecated
         |class Test {
+        |  @deprecated
+        |  val v = 0
+        |
+        |  @deprecated
+        |  var x = 0
+        |
         |  @deprecated("do not use this function!")
         |  def f(): Unit = ()
         |}
@@ -962,6 +968,13 @@ class TestBCode extends DottyBytecodeTest {
       val c = loadClassNode(dir.lookupName("Test.class", directory = false).input)
       assert((c.access & Opcodes.ACC_DEPRECATED) != 0)
       assert((getMethod(c, "f").access & Opcodes.ACC_DEPRECATED) != 0)
+
+      assert((getField(c, "v").access & Opcodes.ACC_DEPRECATED) != 0)
+      assert((getMethod(c, "v").access & Opcodes.ACC_DEPRECATED) != 0)
+
+      assert((getField(c, "x").access & Opcodes.ACC_DEPRECATED) != 0)
+      assert((getMethod(c, "x").access & Opcodes.ACC_DEPRECATED) != 0)
+      assert((getMethod(c, "x_$eq").access & Opcodes.ACC_DEPRECATED) != 0)
     }
   }
 }