Fix parsing Java annotation values (#11809)

Author: noti0na1

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

@@ -359,19 +359,6 @@ object JavaParsers {
       * but instead we skip entire annotation silently.
       */
     def annotation(): Option[Tree] = {
-      object LiteralT:
-        def unapply(token: Token) = Option(token match {
-          case TRUE      => true
-          case FALSE     => false
-          case CHARLIT   => in.name(0)
-          case INTLIT    => in.intVal(false).toInt
-          case LONGLIT   => in.intVal(false)
-          case FLOATLIT  => in.floatVal(false).toFloat
-          case DOUBLELIT => in.floatVal(false)
-          case STRINGLIT => in.name.toString
-          case _         => null
-        }).map(Constant(_))
-
       def classOrId(): Tree =
         val id = qualId()
         if in.lookaheadToken == CLASS then
@@ -398,17 +385,17 @@ object JavaParsers {
         }
 
       def argValue(): Option[Tree] =
-        val tree = in.token match {
-          case LiteralT(c) =>
-            val tree = atSpan(in.offset)(Literal(c))
-            in.nextToken()
-            Some(tree)
-          case AT =>
-            in.nextToken()
-            annotation()
-          case IDENTIFIER => Some(classOrId())
-          case LBRACE => array()
-          case _ => None
+        val tree = tryConstant match {
+          case Some(c) =>
+            Some(atSpan(in.offset)(Literal(c)))
+          case _ => in.token match {
+            case AT =>
+              in.nextToken()
+              annotation()
+            case IDENTIFIER => Some(classOrId())
+            case LBRACE => array()
+            case _ => None
+          }
         }
         if in.token == COMMA || in.token == RBRACE || in.token == RPAREN then
           tree
@@ -716,11 +703,7 @@ object JavaParsers {
 
         in.nextToken() // EQUALS
         if (mods.is(Flags.JavaStatic) && mods.is(Flags.Final)) {
-          val neg = in.token match {
-            case MINUS | BANG => in.nextToken(); true
-            case _ => false
-          }
-          tryLiteral(neg).map(forConst).getOrElse(tpt1)
+          tryConstant.map(forConst).getOrElse(tpt1)
         }
         else tpt1
       }
@@ -976,7 +959,11 @@ object JavaParsers {
       case _         => in.nextToken(); syntaxError("illegal start of type declaration", skipIt = true); List(errorTypeTree)
     }
 
-    def tryLiteral(negate: Boolean = false): Option[Constant] = {
+    def tryConstant: Option[Constant] = {
+      val negate = in.token match {
+        case MINUS | BANG => in.nextToken(); true
+        case _ => false
+      }
       val l = in.token match {
         case TRUE      => !negate
         case FALSE     => negate

tests/run-macros/annot-arg-value-in-java.check

@@ -0,0 +1,11 @@
+J:
+new java.lang.SuppressWarnings(value = "a")
+new java.lang.SuppressWarnings(value = "b")
+new java.lang.SuppressWarnings(value = _root_.scala.Array.apply[java.lang.String]("c", "d")(scala.reflect.ClassTag.apply[java.lang.String](classOf[java.lang.String])))
+JOtherTypes:
+new Annot(value = 1, _, _)
+new Annot(value = -2, _, _)
+new Annot(_, m = false, _)
+new Annot(_, m = true, _)
+new Annot(_, _, n = 1.1)
+new Annot(_, _, n = -2.1)

tests/run-macros/annot-arg-value-in-java/AnnoMacro.scala

@@ -0,0 +1,11 @@
+import scala.quoted.*
+
+inline def showAnnots(inline c: String): Unit = ${ showAnnotsImpl('c) }
+
+def showAnnotsImpl(c: Expr[String])(using Quotes): Expr[Unit] =
+  import quotes.reflect.*
+  val al = Expr(Symbol.requiredClass(c.valueOrError).declaredMethods.flatMap(_.annotations.map(_.show)))
+  '{
+    println($c + ":")
+    $al.foreach(println)
+  }

tests/run-macros/annot-arg-value-in-java/Annot.java

@@ -0,0 +1,5 @@
+public @interface Annot {
+  int value() default 0;
+  boolean m() default false;
+  double n() default 0;
+}

tests/run-macros/annot-arg-value-in-java/J.java

@@ -0,0 +1,23 @@
+public class J {
+  @SuppressWarnings(value = "a")
+  public void f1() {}
+  @SuppressWarnings("b")
+  public void f2() {}
+  @SuppressWarnings({"c", "d"})
+  public void f3() {}
+}
+
+class JOtherTypes {
+  @Annot(1)
+  public void f1() {}
+  @Annot(-2)
+  public void f2() {}
+  @Annot(m = false)
+  public void f3() {}
+  @Annot(m = true)
+  public void f4() {}
+  @Annot(n = 1.1)
+  public void f5() {}
+  @Annot(n = -2.1)
+  public void f6() {}
+}

tests/run-macros/annot-arg-value-in-java/S.scala

@@ -0,0 +1,5 @@
+// Display annotation arguments in Java
+
+@main def Test =
+  showAnnots("J")
+  showAnnots("JOtherTypes")