Decode fields

src/main/scala/ch/epfl/scala/decoder/BinaryDecoder.scala

@@ -14,6 +14,7 @@ import tastyquery.jdk.ClasspathLoaders
 
 import java.nio.file.Path
 import scala.util.matching.Regex
+import tastyquery.Exceptions.NonMethodReferenceException
 
 object BinaryDecoder:
   def apply(classEntries: Seq[Path])(using ThrowOrWarn): BinaryDecoder =
@@ -107,6 +108,75 @@ class BinaryDecoder(using Context, ThrowOrWarn):
     candidates.singleOrThrow(method)
   end decode
 
+  def decode(field: binary.Field): DecodedField =
+    val decodedClass = decode(field.declaringClass)
+    decode(decodedClass, field)
+
+  def decode(decodedClass: DecodedClass, field: binary.Field): DecodedField =
+    def tryDecode(f: PartialFunction[binary.Field, Seq[DecodedField]]): Seq[DecodedField] =
+      f.applyOrElse(field, _ => Seq.empty[DecodedField])
+
+    extension (xs: Seq[DecodedField])
+      def orTryDecode(f: PartialFunction[binary.Field, Seq[DecodedField]]): Seq[DecodedField] =
+        if xs.nonEmpty then xs else f.applyOrElse(field, _ => Seq.empty[DecodedField])
+    val decodedFields =
+      tryDecode {
+        case Patterns.LazyVal(name) =>
+          for
+            owner <- decodedClass.classSymbol.toSeq ++ decodedClass.linearization.filter(_.isTrait)
+            sym <- owner.declarations.collect {
+              case sym: TermSymbol if sym.nameStr == name && sym.isModuleOrLazyVal => sym
+            }
+          yield DecodedField.ValDef(decodedClass, sym)
+        case Patterns.Module() =>
+          decodedClass.classSymbol.flatMap(_.moduleValue).map(DecodedField.ModuleVal(decodedClass, _)).toSeq
+        case Patterns.Offset(nbr) =>
+          Seq(DecodedField.LazyValOffset(decodedClass, nbr, defn.LongType))
+        case Patterns.OuterField() =>
+          decodedClass.symbolOpt
+            .flatMap(_.outerClass)
+            .map(outerClass => DecodedField.Outer(decodedClass, outerClass.selfType))
+            .toSeq
+        case Patterns.SerialVersionUID() =>
+          Seq(DecodedField.SerialVersionUID(decodedClass, defn.LongType))
+        case Patterns.LazyValBitmap(name) =>
+          Seq(DecodedField.LazyValBitmap(decodedClass, defn.BooleanType, name))
+        case Patterns.AnyValCapture() =>
+          for
+            classSym <- decodedClass.symbolOpt.toSeq
+            outerClass <- classSym.outerClass.toSeq
+            if outerClass.isSubClass(defn.AnyValClass)
+            sym <- outerClass.declarations.collect {
+              case sym: TermSymbol if sym.isVal && !sym.isMethod => sym
+            }
+          yield DecodedField.Capture(decodedClass, sym)
+        case Patterns.Capture(names) =>
+          decodedClass.symbolOpt.toSeq
+            .flatMap(CaptureCollector.collectCaptures)
+            .filter { captureSym =>
+              names.exists {
+                case Patterns.LazyVal(name) => name == captureSym.nameStr
+                case name => name == captureSym.nameStr
+              }
+            }
+            .map(DecodedField.Capture(decodedClass, _))
+
+        case _ if field.isStatic && decodedClass.isJava =>
+          for
+            owner <- decodedClass.companionClassSymbol.toSeq
+            sym <- owner.declarations.collect { case sym: TermSymbol if sym.nameStr == field.name => sym }
+          yield DecodedField.ValDef(decodedClass, sym)
+      }.orTryDecode { case _ =>
+        for
+          owner <- withCompanionIfExtendsJavaLangEnum(decodedClass) ++ decodedClass.linearization.filter(_.isTrait)
+          sym <- owner.declarations.collect {
+            case sym: TermSymbol if matchTargetName(field, sym) && !sym.isMethod => sym
+          }
+        yield DecodedField.ValDef(decodedClass, sym)
+      }
+    decodedFields.singleOrThrow(field)
+  end decode
+
   private def reduceAmbiguityOnClasses(syms: Seq[DecodedClass]): Seq[DecodedClass] =
     if syms.size > 1 then
       val reduced = syms.filterNot(sym => syms.exists(enclose(sym, _)))
@@ -476,13 +546,8 @@ class BinaryDecoder(using Context, ThrowOrWarn):
       .map(target => DecodedMethod.TraitStaticForwarder(decode(decodedClass, target)))
 
   private def decodeOuter(decodedClass: DecodedClass): Option[DecodedMethod.OuterAccessor] =
-    def outerClass(sym: Symbol): Option[ClassSymbol] =
-      sym.owner match
-        case null => None
-        case owner if owner.isClass => Some(owner.asClass)
-        case owner => outerClass(owner)
     decodedClass.symbolOpt
-      .flatMap(outerClass)
+      .flatMap(_.outerClass)
       .map(outerClass => DecodedMethod.OuterAccessor(decodedClass, outerClass.thisType))
 
   private def decodeTraitInitializer(
@@ -616,11 +681,18 @@ class BinaryDecoder(using Context, ThrowOrWarn):
         DecodedMethod.MixinForwarder(decodedClass, staticForwarder.target)
       }
 
-  private def withCompanionIfExtendsAnyVal(cls: ClassSymbol): Seq[ClassSymbol] =
-    cls.companionClass match
-      case Some(companionClass) if companionClass.isSubClass(defn.AnyValClass) =>
-        Seq(cls, companionClass)
-      case _ => Seq(cls)
+  private def withCompanionIfExtendsAnyVal(decodedClass: DecodedClass): Seq[Symbol] = decodedClass match
+    case classDef: DecodedClass.ClassDef =>
+      Seq(classDef.symbol) ++ classDef.symbol.companionClass.filter(_.isSubClass(defn.AnyValClass))
+    case _: DecodedClass.SyntheticCompanionClass => Seq.empty
+    case anonFun: DecodedClass.SAMOrPartialFunction => Seq(anonFun.symbol)
+    case inlined: DecodedClass.InlinedClass => withCompanionIfExtendsAnyVal(inlined.underlying)
+
+  private def withCompanionIfExtendsJavaLangEnum(decodedClass: DecodedClass): Seq[ClassSymbol] =
+    decodedClass.classSymbol.toSeq.flatMap { cls =>
+      if cls.isSubClass(defn.javaLangEnumClass) then Seq(cls) ++ cls.companionClass
+      else Seq(cls)
+    }
 
   private def decodeAdaptedAnonFun(decodedClass: DecodedClass, method: binary.Method): Seq[DecodedMethod] =
     if method.instructions.nonEmpty then
@@ -786,13 +858,6 @@ class BinaryDecoder(using Context, ThrowOrWarn):
   private def collectLiftedTrees[S](decodedClass: DecodedClass, method: binary.Method)(
       matcher: PartialFunction[LiftedTree[?], LiftedTree[S]]
   ): Seq[LiftedTree[S]] =
-    def withCompanionIfExtendsAnyVal(decodedClass: DecodedClass): Seq[Symbol] = decodedClass match
-      case classDef: DecodedClass.ClassDef =>
-        Seq(classDef.symbol) ++ classDef.symbol.companionClass.filter(_.isSubClass(defn.AnyValClass))
-      case _: DecodedClass.SyntheticCompanionClass => Seq.empty
-      case anonFun: DecodedClass.SAMOrPartialFunction => Seq(anonFun.symbol)
-      case inlined: DecodedClass.InlinedClass => withCompanionIfExtendsAnyVal(inlined.underlying)
-
     val owners = withCompanionIfExtendsAnyVal(decodedClass)
     val sourceLines =
       if owners.size == 2 && method.allParameters.exists(p => p.name.matches("\\$this\\$\\d+")) then
@@ -823,6 +888,9 @@ class BinaryDecoder(using Context, ThrowOrWarn):
   private def matchTargetName(method: binary.Method, symbol: TermSymbol): Boolean =
     method.unexpandedDecodedNames.map(_.stripSuffix("$")).contains(symbol.targetNameStr)
 
+  private def matchTargetName(field: binary.Field, symbol: TermSymbol): Boolean =
+    field.unexpandedDecodedNames.map(_.stripSuffix("$")).contains(symbol.targetNameStr)
+
   private case class SourceParams(
       declaredParamNames: Seq[UnsignedTermName],
       declaredParamTypes: Seq[Type],

src/main/scala/ch/epfl/scala/decoder/DecodedSymbol.scala

@@ -160,3 +160,35 @@ object DecodedMethod:
     override def toString: String =
       if underlying.isInstanceOf[InlinedMethod] then underlying.toString
       else s"$underlying (inlined)"
+
+sealed trait DecodedField extends DecodedSymbol:
+  def owner: DecodedClass
+  override def symbolOpt: Option[TermSymbol] = None
+  def declaredType: TypeOrMethodic
+
+object DecodedField:
+  final class ValDef(val owner: DecodedClass, val symbol: TermSymbol) extends DecodedField:
+    def declaredType: TypeOrMethodic = symbol.declaredType
+    override def symbolOpt: Option[TermSymbol] = Some(symbol)
+    override def toString: String = s"ValDef($owner, ${symbol.showBasic})"
+
+  final class ModuleVal(val owner: DecodedClass, val symbol: TermSymbol) extends DecodedField:
+    def declaredType: TypeOrMethodic = symbol.declaredType
+    override def symbolOpt: Option[TermSymbol] = Some(symbol)
+    override def toString: String = s"ModuleVal($owner, ${symbol.showBasic})"
+
+  final class LazyValOffset(val owner: DecodedClass, val index: Int, val declaredType: Type) extends DecodedField:
+    override def toString: String = s"LazyValOffset($owner, $index)"
+
+  final class Outer(val owner: DecodedClass, val declaredType: Type) extends DecodedField:
+    override def toString: String = s"Outer($owner, ${declaredType.showBasic})"
+
+  final class SerialVersionUID(val owner: DecodedClass, val declaredType: Type) extends DecodedField:
+    override def toString: String = s"SerialVersionUID($owner)"
+
+  final class Capture(val owner: DecodedClass, val symbol: TermSymbol) extends DecodedField:
+    def declaredType: TypeOrMethodic = symbol.declaredType
+    override def toString: String = s"Capture($owner, ${symbol.showBasic})"
+
+  final class LazyValBitmap(val owner: DecodedClass, val declaredType: Type, val name: String) extends DecodedField:
+    override def toString: String = s"LazyValBitmap($owner, , ${declaredType.showBasic})"

src/main/scala/ch/epfl/scala/decoder/StackTraceFormatter.scala

@@ -10,6 +10,12 @@ import tastyquery.Types.*
 import scala.annotation.tailrec
 
 class StackTraceFormatter(using ThrowOrWarn):
+  def format(field: DecodedField): String =
+    val typeAscription = field.declaredType match
+      case tpe: Type => ": " + format(tpe)
+      case tpe => format(tpe)
+    formatOwner(field).dot(formatName(field)) + typeAscription
+
   def format(cls: DecodedClass): String =
     cls match
       case cls: DecodedClass.ClassDef => formatQualifiedName(cls.symbol)
@@ -60,6 +66,19 @@ class StackTraceFormatter(using ThrowOrWarn):
       case method: DecodedMethod.SAMOrPartialFunctionConstructor => format(method.owner)
       case method: DecodedMethod.InlinedMethod => formatOwner(method.underlying)
 
+  private def formatOwner(field: DecodedField): String =
+    format(field.owner)
+
+  private def formatName(field: DecodedField): String =
+    field match
+      case field: DecodedField.ValDef => formatName(field.symbol)
+      case field: DecodedField.ModuleVal => ""
+      case field: DecodedField.LazyValOffset => "<offset " + field.index + ">"
+      case field: DecodedField.Outer => "<outer>"
+      case field: DecodedField.SerialVersionUID => "<serialVersionUID>"
+      case field: DecodedField.Capture => formatName(field.symbol).dot("<capture>")
+      case field: DecodedField.LazyValBitmap => field.name.dot("<lazy val bitmap>")
+
   private def formatName(method: DecodedMethod): String =
     method match
       case method: DecodedMethod.ValOrDefDef => formatName(method.symbol)

src/main/scala/ch/epfl/scala/decoder/binary/ClassType.scala

@@ -9,6 +9,7 @@ trait ClassType extends Type:
   def declaredField(name: String): Option[Field]
   def declaredMethod(name: String, descriptor: String): Option[Method]
   def declaredMethods: Seq[Method]
+  def declaredFields: Seq[Field]
   def classLoader: BinaryClassLoader
 
   def isObject = name.endsWith("$")

src/main/scala/ch/epfl/scala/decoder/binary/Field.scala

@@ -3,3 +3,4 @@ package ch.epfl.scala.decoder.binary
 trait Field extends Symbol:
   def declaringClass: ClassType
   def `type`: Type
+  def isStatic: Boolean

src/main/scala/ch/epfl/scala/decoder/internal/CaptureCollector.scala

@@ -0,0 +1,47 @@
+package ch.epfl.scala.decoder.internal
+
+import tastyquery.Trees.*
+import scala.collection.mutable
+import tastyquery.Symbols.*
+import tastyquery.Traversers.*
+import tastyquery.Contexts.*
+import tastyquery.SourcePosition
+import tastyquery.Types.*
+import tastyquery.Traversers
+import ch.epfl.scala.decoder.ThrowOrWarn
+import scala.languageFeature.postfixOps
+
+object CaptureCollector:
+  def collectCaptures(cls: ClassSymbol | TermSymbol)(using Context, ThrowOrWarn): Set[TermSymbol] =
+    val collector = CaptureCollector(cls)
+    collector.traverse(cls.tree)
+    collector.capture.toSet
+
+class CaptureCollector(cls: ClassSymbol | TermSymbol)(using Context, ThrowOrWarn) extends TreeTraverser:
+  val capture: mutable.Set[TermSymbol] = mutable.Set.empty
+  val alreadySeen: mutable.Set[Symbol] = mutable.Set.empty
+
+  def loopCollect(symbol: Symbol)(collect: => Unit): Unit =
+    if !alreadySeen.contains(symbol) then
+      alreadySeen += symbol
+      collect
+  override def traverse(tree: Tree): Unit =
+    tree match
+      case _: TypeTree => ()
+      case ident: Ident =>
+        for sym <- ident.safeSymbol.collect { case sym: TermSymbol => sym } do
+          // check that sym is local
+          // and check that no owners of sym is cls
+          if !alreadySeen.contains(sym) then
+            if sym.isLocal then
+              if !ownersIsCls(sym) then capture += sym
+              if sym.isMethod || sym.isLazyVal then loopCollect(sym)(sym.tree.foreach(traverse))
+              else if sym.isModuleVal then loopCollect(sym)(sym.moduleClass.flatMap(_.tree).foreach(traverse))
+      case _ => super.traverse(tree)
+
+    def ownersIsCls(sym: Symbol): Boolean =
+      sym.owner match
+        case owner: Symbol =>
+          if owner == cls then true
+          else ownersIsCls(owner)
+        case null => false

src/main/scala/ch/epfl/scala/decoder/internal/Definitions.scala

@@ -15,6 +15,7 @@ class Definitions(using ctx: Context):
   val PartialFunctionClass = scalaPackage.getDecl(typeName("PartialFunction")).get.asClass
   val AbstractPartialFunctionClass = scalaRuntimePackage.getDecl(typeName("AbstractPartialFunction")).get.asClass
   val SerializableClass = javaIoPackage.getDecl(typeName("Serializable")).get.asClass
+  val javaLangEnumClass = javaLangPackage.getDecl(typeName("Enum")).get.asClass
 
   val SerializedLambdaType: Type = TypeRef(javaLangInvokePackage.packageRef, typeName("SerializedLambda"))
   val DeserializeLambdaType = MethodType(List(SimpleName("arg0")), List(SerializedLambdaType), ObjectType)

src/main/scala/ch/epfl/scala/decoder/internal/LiftedTreeCollector.scala

@@ -8,7 +8,6 @@ import tastyquery.Contexts.*
 import tastyquery.SourcePosition
 import tastyquery.Types.*
 import tastyquery.Traversers
-import tastyquery.Exceptions.NonMethodReferenceException
 import ch.epfl.scala.decoder.ThrowOrWarn
 
 /**

src/main/scala/ch/epfl/scala/decoder/internal/Patterns.scala

@@ -135,6 +135,45 @@ object Patterns:
           "(.+)\\$i\\d+".r.unapplySeq(xs(0)).map(_(0)).getOrElse(xs(0))
         }
 
+  object LazyVal:
+    def unapply(field: binary.Field): Option[String] = unapply(field.decodedName)
+
+    def unapply(name: String): Option[String] =
+      """(.*)\$lzy\d+""".r.unapplySeq(name).map(xs => xs(0).stripSuffix("$"))
+
+  object Module:
+    def unapply(field: binary.Field): Boolean = field.name == "MODULE$"
+
+  object Offset:
+    def unapply(field: binary.Field): Option[Int] =
+      """OFFSET\$(?:_m_)?(\d+)""".r.unapplySeq(field.name).map(xs => xs(0).toInt)
+
+  object OuterField:
+    def unapply(field: binary.Field): Boolean = field.name == "$outer"
+
+  object SerialVersionUID:
+    def unapply(field: binary.Field): Boolean = field.name == "serialVersionUID"
+
+  object AnyValCapture:
+    def unapply(field: binary.Field): Boolean =
+      field.name.matches("\\$this\\$\\d+")
+
+  object Capture:
+    def unapply(field: binary.Field): Option[Seq[String]] =
+      field.extractFromDecodedNames("(.+)\\$\\d+".r)(xs => xs(0))
+
+  object LazyValBitmap:
+    def unapply(field: binary.Field): Option[String] =
+      "(.+)bitmap\\$\\d+".r.unapplySeq(field.decodedName).map(xs => xs(0))
+
+  extension (field: binary.Field)
+    private def extractFromDecodedNames[T](regex: Regex)(extract: List[String] => T): Option[Seq[T]] =
+      val extracted = field.unexpandedDecodedNames
+        .flatMap(regex.unapplySeq)
+        .map(extract)
+        .distinct
+      if extracted.nonEmpty then Some(extracted) else None
+
   extension (method: binary.Method)
     private def extractFromDecodedNames[T](regex: Regex)(extract: List[String] => T): Option[Seq[T]] =
       val extracted = method.unexpandedDecodedNames

src/main/scala/ch/epfl/scala/decoder/internal/extensions.scala

@@ -21,6 +21,12 @@ extension (symbol: Symbol)
   def isInline = symbol.isTerm && symbol.asTerm.isInline
   def nameStr: String = symbol.name.toString
 
+  def outerClass: Option[ClassSymbol] =
+    symbol.owner match
+      case null => None
+      case owner: ClassSymbol => Some(owner)
+      case owner => owner.outerClass
+
   def showBasic =
     val span = symbol.tree.map(_.pos) match
       case Some(pos) if pos.isFullyDefined =>
@@ -307,3 +313,14 @@ extension (method: DecodedMethod)
       case _: DecodedMethod.SAMOrPartialFunctionConstructor => true
       case method: DecodedMethod.InlinedMethod => method.underlying.isGenerated
       case _ => false
+
+extension (field: DecodedField)
+  def isGenerated: Boolean =
+    field match
+      case field: DecodedField.ValDef => false
+      case field: DecodedField.ModuleVal => true
+      case field: DecodedField.LazyValOffset => true
+      case field: DecodedField.Outer => true
+      case field: DecodedField.SerialVersionUID => true
+      case field: DecodedField.Capture => true
+      case field: DecodedField.LazyValBitmap => true

src/main/scala/ch/epfl/scala/decoder/javareflect/JavaReflectClass.scala

@@ -41,3 +41,6 @@ class JavaReflectClass(cls: Class[?], extraInfo: ExtraClassInfo, override val cl
       val methodInfo = extraInfo.getMethodInfo(sig)
       JavaReflectConstructor(c, sig, methodInfo, classLoader)
     }
+
+  override def declaredFields: Seq[binary.Field] =
+    cls.getDeclaredFields().map(f => JavaReflectField(f, classLoader))

src/main/scala/ch/epfl/scala/decoder/javareflect/JavaReflectField.scala

@@ -3,6 +3,7 @@ package ch.epfl.scala.decoder.javareflect
 import ch.epfl.scala.decoder.binary
 
 import java.lang.reflect.Field
+import java.lang.reflect.Modifier
 
 class JavaReflectField(field: Field, loader: JavaReflectLoader) extends binary.Field:
   override def name: String = field.getName
@@ -11,5 +12,9 @@ class JavaReflectField(field: Field, loader: JavaReflectLoader) extends binary.F
 
   override def declaringClass: binary.ClassType = loader.loadClass(field.getDeclaringClass)
 
+  override def isStatic: Boolean = Modifier.isStatic(field.getModifiers)
+
   override def `type`: binary.Type =
     loader.loadClass(field.getType)
+
+  override def toString: String = field.toString