Fix evaluation of value classes in Scala 3

scalacenter · Jul 14, 2023 · ebca4c0 · ebca4c0
1 parent 9ec2eb1
commit ebca4c0
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Showing 2 changed files with 39 additions and 7 deletions.
diff --git a/...expression-compiler/src/main/scala-3/dotty/tools/dotc/evaluation/ResolveReflectEval.scala b/...expression-compiler/src/main/scala-3/dotty/tools/dotc/evaluation/ResolveReflectEval.scala
@@ -151,20 +151,25 @@ class ResolveReflectEval(using exprCtx: ExpressionContext) extends MiniPhase:
         case _ => tree
 
     def boxIfValueClass(term: TermSymbol, tree: Tree): Tree =
-      atPhase(Phases.elimErasedValueTypePhase)(term.info) match
-        case tpe: ErasedValueType =>
-          boxValueClass(tpe.tycon.typeSymbol.asClass, tree)
-        case tpe => tree
+      getErasedValueType(atPhase(Phases.elimErasedValueTypePhase)(term.info)) match
+        case Some(erasedValueType) =>
+          boxValueClass(erasedValueType.tycon.typeSymbol.asClass, tree)
+        case None => tree
 
     def boxValueClass(valueClass: ClassSymbol, tree: Tree): Tree =
       // qualifier is null: a value class cannot be nested into a class
       val ctor = valueClass.primaryConstructor.asTerm
       callConstructor(nullLiteral, ctor, List(tree))
 
     def unboxIfValueClass(term: TermSymbol, tree: Tree): Tree =
-      atPhase(Phases.elimErasedValueTypePhase)(term.info) match
-        case tpe: ErasedValueType => unboxValueClass(tree, tpe)
-        case tpe => tree
+      getErasedValueType(atPhase(Phases.elimErasedValueTypePhase)(term.info)) match
+        case Some(erasedValueType) => unboxValueClass(tree, erasedValueType)
+        case None => tree
+
+    private def getErasedValueType(tpe: Type): Option[ErasedValueType] = tpe match
+      case tpe: ErasedValueType => Some(tpe)
+      case tpe: MethodOrPoly => getErasedValueType(tpe.resultType)
+      case tpe => None
 
     private def unboxValueClass(tree: Tree, tpe: ErasedValueType): Tree =
       val cls = tpe.tycon.typeSymbol.asClass

diff --git a/modules/tests/src/test/scala/ch/epfl/scala/debugadapter/ScalaEvaluationTests.scala b/modules/tests/src/test/scala/ch/epfl/scala/debugadapter/ScalaEvaluationTests.scala
@@ -2011,6 +2011,33 @@ abstract class ScalaEvaluationTests(scalaVersion: ScalaVersion) extends DebugTes
     // a pure expression does nothing in statement position
     check(Breakpoint(8), Evaluation.successOrIgnore("m", 1, ignore = isScala2))
   }
+
+  test("i425") {
+    val source =
+      """|package example
+         |
+         |object Rewrites {
+         |  private class Patch(var span: Span)
+         |  
+         |  def main(args: Array[String]): Unit = {
+         |    val patch = Patch(Span(0))
+         |    println("ok")
+         |  }
+         |}
+         |
+         |class Span(start: Int) extends AnyVal {
+         |  def end = start + 1
+         |}
+         |""".stripMargin
+    implicit val debuggee: TestingDebuggee =
+      TestingDebuggee.mainClass(source, "example.Rewrites", scalaVersion)
+    check(
+      Breakpoint(8),
+      Evaluation.success("patch.span", 0),
+      Evaluation.success("patch.span = new Span(1)", ()),
+      Evaluation.success("patch.span", 1)
+    )
+  }
 }
 
 abstract class Scala2EvaluationTests(val scalaVersion: ScalaVersion) extends ScalaEvaluationTests(scalaVersion) {