Extract Tree utils from Reflection

* Allows TreeMap, TreeTraverser and TreeAccumulator to be extended in non local classes
* Removes logic that does not belong in Reflection

Author: nicolasstucki

community-build/community-projects/utest

@@ -119,7 +119,7 @@ def macroImpl()(qctx: QuoteContext): Expr[Unit] = {
 
 ### Tree Utilities
 
-`scala.tasty.reflect.TreeUtils` contains three facilities for tree traversal and
+`scala.tasty.reflect` contains three facilities for tree traversal and
 transformations.
 
 `TreeAccumulator` ties the knot of a traversal. By calling `foldOver(x, tree))`
@@ -144,7 +144,7 @@ but without returning any value. Finally a `TreeMap` performs a transformation.
 
 #### Let
 
-`scala.tasty.reflect.utils.TreeUtils` also offers a method `let` that allows us
+`scala.tasty.Reflection` also offers a method `let` that allows us
 to bind the `rhs` to a `val` and use it in `body`. Additionally, `lets` binds
 the given `terms` to names and use them in the `body`. Their type definitions
 are shown below:

docs/docs/reference/metaprogramming/tasty-reflect.md

@@ -156,7 +156,9 @@ private[quoted] object Matcher {
               if patternHole.symbol == internal.Definitions_InternalQuoted_patternHole =>
             def bodyFn(lambdaArgs: List[Tree]): Tree = {
               val argsMap = args.map(_.symbol).zip(lambdaArgs.asInstanceOf[List[Term]]).toMap
-              new TreeMap {
+              new scala.tasty.reflect.TreeMap {
+                val reflect: qctx.tasty.type = qctx.tasty
+                import reflect.{given,  _}
                 override def transformTerm(tree: Term)(given ctx: Context): Term =
                   tree match
                     case tree: Ident => summon[Env].get(tree.symbol).flatMap(argsMap.get).getOrElse(tree)
@@ -317,8 +319,10 @@ private[quoted] object Matcher {
         if freePatternVars(term).isEmpty then Some(term) else None
 
       /** Return all free variables of the term defined in the pattern (i.e. defined in `Env`) */
-      def freePatternVars(term: Term)(given qctx: Context, env: Env): Set[Symbol] =
-        val accumulator = new TreeAccumulator[Set[Symbol]] {
+      def freePatternVars(term: Term)(given ctx: Context, env: Env): Set[Symbol] =
+        val accumulator = new scala.tasty.reflect.TreeAccumulator[Set[Symbol]] {
+          val reflect: qctx.tasty.type = qctx.tasty
+          import reflect.{given, _}
           def foldTree(x: Set[Symbol], tree: Tree)(given ctx: Context): Set[Symbol] =
             tree match
               case tree: Ident if env.contains(tree.symbol) => foldOverTree(x + tree.symbol, tree)

library/src/scala/internal/quoted/Matcher.scala

@@ -65,7 +65,8 @@ object UnsafeExpr {
   private def bodyFn[t](given qctx: QuoteContext)(e: qctx.tasty.Term, params: List[qctx.tasty.ValDef], args: List[qctx.tasty.Term]): qctx.tasty.Term = {
     import qctx.tasty.{given, _}
     val map = params.map(_.symbol).zip(args).toMap
-    new TreeMap {
+    new scala.tasty.reflect.TreeMap {
+      val reflect: qctx.tasty.type = qctx.tasty
       override def transformTerm(tree: Term)(given ctx: Context): Term =
         super.transformTerm(tree) match
           case tree: Ident => map.getOrElse(tree.symbol, tree)

library/src/scala/quoted/unsafe/UnsafeExpr.scala

@@ -2731,265 +2731,7 @@ class Reflection(private[scala] val internal: CompilerInterface) { self =>
   //   UTILS   //
   ///////////////
 
-  abstract class TreeAccumulator[X] {
-
-    // Ties the knot of the traversal: call `foldOver(x, tree))` to dive in the `tree` node.
-    def foldTree(x: X, tree: Tree)(given ctx: Context): X
-
-    def foldTrees(x: X, trees: Iterable[Tree])(given ctx: Context): X = trees.foldLeft(x)(foldTree)
-
-    def foldOverTree(x: X, tree: Tree)(given ctx: Context): X = {
-      def localCtx(definition: Definition): Context = definition.symbol.localContext
-      tree match {
-        case Ident(_) =>
-          x
-        case Select(qualifier, _) =>
-          foldTree(x, qualifier)
-        case This(qual) =>
-          x
-        case Super(qual, _) =>
-          foldTree(x, qual)
-        case Apply(fun, args) =>
-          foldTrees(foldTree(x, fun), args)
-        case TypeApply(fun, args) =>
-          foldTrees(foldTree(x, fun), args)
-        case Literal(const) =>
-          x
-        case New(tpt) =>
-          foldTree(x, tpt)
-        case Typed(expr, tpt) =>
-          foldTree(foldTree(x, expr), tpt)
-        case NamedArg(_, arg) =>
-          foldTree(x, arg)
-        case Assign(lhs, rhs) =>
-          foldTree(foldTree(x, lhs), rhs)
-        case Block(stats, expr) =>
-          foldTree(foldTrees(x, stats), expr)
-        case If(cond, thenp, elsep) =>
-          foldTree(foldTree(foldTree(x, cond), thenp), elsep)
-        case While(cond, body) =>
-          foldTree(foldTree(x, cond), body)
-        case Closure(meth, tpt) =>
-          foldTree(x, meth)
-        case Match(selector, cases) =>
-          foldTrees(foldTree(x, selector), cases)
-        case Return(expr) =>
-          foldTree(x, expr)
-        case Try(block, handler, finalizer) =>
-          foldTrees(foldTrees(foldTree(x, block), handler), finalizer)
-        case Repeated(elems, elemtpt) =>
-          foldTrees(foldTree(x, elemtpt), elems)
-        case Inlined(call, bindings, expansion) =>
-          foldTree(foldTrees(x, bindings), expansion)
-        case vdef @ ValDef(_, tpt, rhs) =>
-          val ctx = localCtx(vdef)
-          given Context = ctx
-          foldTrees(foldTree(x, tpt), rhs)
-        case ddef @ DefDef(_, tparams, vparamss, tpt, rhs) =>
-          val ctx = localCtx(ddef)
-          given Context = ctx
-          foldTrees(foldTree(vparamss.foldLeft(foldTrees(x, tparams))(foldTrees), tpt), rhs)
-        case tdef @ TypeDef(_, rhs) =>
-          val ctx = localCtx(tdef)
-          given Context = ctx
-          foldTree(x, rhs)
-        case cdef @ ClassDef(_, constr, parents, derived, self, body) =>
-          val ctx = localCtx(cdef)
-          given Context = ctx
-          foldTrees(foldTrees(foldTrees(foldTrees(foldTree(x, constr), parents), derived), self), body)
-        case Import(expr, _) =>
-          foldTree(x, expr)
-        case clause @ PackageClause(pid, stats) =>
-          foldTrees(foldTree(x, pid), stats)(given clause.symbol.localContext)
-        case Inferred() => x
-        case TypeIdent(_) => x
-        case TypeSelect(qualifier, _) => foldTree(x, qualifier)
-        case Projection(qualifier, _) => foldTree(x, qualifier)
-        case Singleton(ref) => foldTree(x, ref)
-        case Refined(tpt, refinements) => foldTrees(foldTree(x, tpt), refinements)
-        case Applied(tpt, args) => foldTrees(foldTree(x, tpt), args)
-        case ByName(result) => foldTree(x, result)
-        case Annotated(arg, annot) => foldTree(foldTree(x, arg), annot)
-        case LambdaTypeTree(typedefs, arg) => foldTree(foldTrees(x, typedefs), arg)
-        case TypeBind(_, tbt) => foldTree(x, tbt)
-        case TypeBlock(typedefs, tpt) => foldTree(foldTrees(x, typedefs), tpt)
-        case MatchTypeTree(boundopt, selector, cases) =>
-          foldTrees(foldTree(boundopt.fold(x)(foldTree(x, _)), selector), cases)
-        case WildcardTypeTree() => x
-        case TypeBoundsTree(lo, hi) => foldTree(foldTree(x, lo), hi)
-        case CaseDef(pat, guard, body) => foldTree(foldTrees(foldTree(x, pat), guard), body)
-        case TypeCaseDef(pat, body) => foldTree(foldTree(x, pat), body)
-        case Bind(_, body) => foldTree(x, body)
-        case Unapply(fun, implicits, patterns) => foldTrees(foldTrees(foldTree(x, fun), implicits), patterns)
-        case Alternatives(patterns) => foldTrees(x, patterns)
-      }
-    }
-  }
-
-  abstract class TreeTraverser extends TreeAccumulator[Unit] {
-
-    def traverseTree(tree: Tree)(given ctx: Context): Unit = traverseTreeChildren(tree)
-
-    def foldTree(x: Unit, tree: Tree)(given ctx: Context): Unit = traverseTree(tree)
-
-    protected def traverseTreeChildren(tree: Tree)(given ctx: Context): Unit = foldOverTree((), tree)
-
-  }
-
-  abstract class TreeMap { self =>
-
-    def transformTree(tree: Tree)(given ctx: Context): Tree = {
-      tree match {
-        case tree: PackageClause =>
-          PackageClause.copy(tree)(transformTerm(tree.pid).asInstanceOf[Ref], transformTrees(tree.stats)(given tree.symbol.localContext))
-        case tree: Import =>
-          Import.copy(tree)(transformTerm(tree.expr), tree.selectors)
-        case tree: Statement =>
-          transformStatement(tree)
-        case tree: TypeTree => transformTypeTree(tree)
-        case tree: TypeBoundsTree => tree // TODO traverse tree
-        case tree: WildcardTypeTree => tree // TODO traverse tree
-        case tree: CaseDef =>
-          transformCaseDef(tree)
-        case tree: TypeCaseDef =>
-          transformTypeCaseDef(tree)
-        case pattern: Bind =>
-          Bind.copy(pattern)(pattern.name, pattern.pattern)
-        case pattern: Unapply =>
-          Unapply.copy(pattern)(transformTerm(pattern.fun), transformSubTrees(pattern.implicits), transformTrees(pattern.patterns))
-        case pattern: Alternatives =>
-          Alternatives.copy(pattern)(transformTrees(pattern.patterns))
-      }
-    }
-
-    def transformStatement(tree: Statement)(given ctx: Context): Statement = {
-      def localCtx(definition: Definition): Context = definition.symbol.localContext
-      tree match {
-        case tree: Term =>
-          transformTerm(tree)
-        case tree: ValDef =>
-          val ctx = localCtx(tree)
-          given Context = ctx
-          val tpt1 = transformTypeTree(tree.tpt)
-          val rhs1 = tree.rhs.map(x => transformTerm(x))
-          ValDef.copy(tree)(tree.name, tpt1, rhs1)
-        case tree: DefDef =>
-          val ctx = localCtx(tree)
-          given Context = ctx
-          DefDef.copy(tree)(tree.name, transformSubTrees(tree.typeParams), tree.paramss mapConserve (transformSubTrees(_)), transformTypeTree(tree.returnTpt), tree.rhs.map(x => transformTerm(x)))
-        case tree: TypeDef =>
-          val ctx = localCtx(tree)
-          given Context = ctx
-          TypeDef.copy(tree)(tree.name, transformTree(tree.rhs))
-        case tree: ClassDef =>
-          ClassDef.copy(tree)(tree.name, tree.constructor, tree.parents, tree.derived, tree.self, tree.body)
-        case tree: Import =>
-          Import.copy(tree)(transformTerm(tree.expr), tree.selectors)
-      }
-    }
-
-    def transformTerm(tree: Term)(given ctx: Context): Term = {
-      tree match {
-        case Ident(name) =>
-          tree
-        case Select(qualifier, name) =>
-          Select.copy(tree)(transformTerm(qualifier), name)
-        case This(qual) =>
-          tree
-        case Super(qual, mix) =>
-          Super.copy(tree)(transformTerm(qual), mix)
-        case Apply(fun, args) =>
-          Apply.copy(tree)(transformTerm(fun), transformTerms(args))
-        case TypeApply(fun, args) =>
-          TypeApply.copy(tree)(transformTerm(fun), transformTypeTrees(args))
-        case Literal(const) =>
-          tree
-        case New(tpt) =>
-          New.copy(tree)(transformTypeTree(tpt))
-        case Typed(expr, tpt) =>
-          Typed.copy(tree)(transformTerm(expr), transformTypeTree(tpt))
-        case tree: NamedArg =>
-          NamedArg.copy(tree)(tree.name, transformTerm(tree.value))
-        case Assign(lhs, rhs) =>
-          Assign.copy(tree)(transformTerm(lhs), transformTerm(rhs))
-        case Block(stats, expr) =>
-          Block.copy(tree)(transformStats(stats), transformTerm(expr))
-        case If(cond, thenp, elsep) =>
-          If.copy(tree)(transformTerm(cond), transformTerm(thenp), transformTerm(elsep))
-        case Closure(meth, tpt) =>
-          Closure.copy(tree)(transformTerm(meth), tpt)
-        case Match(selector, cases) =>
-          Match.copy(tree)(transformTerm(selector), transformCaseDefs(cases))
-        case Return(expr) =>
-          Return.copy(tree)(transformTerm(expr))
-        case While(cond, body) =>
-          While.copy(tree)(transformTerm(cond), transformTerm(body))
-        case Try(block, cases, finalizer) =>
-          Try.copy(tree)(transformTerm(block), transformCaseDefs(cases), finalizer.map(x => transformTerm(x)))
-        case Repeated(elems, elemtpt) =>
-          Repeated.copy(tree)(transformTerms(elems), transformTypeTree(elemtpt))
-        case Inlined(call, bindings, expansion) =>
-          Inlined.copy(tree)(call, transformSubTrees(bindings), transformTerm(expansion)/*()call.symbol.localContext)*/)
-      }
-    }
-
-    def transformTypeTree(tree: TypeTree)(given ctx: Context): TypeTree = tree match {
-      case Inferred() => tree
-      case tree: TypeIdent => tree
-      case tree: TypeSelect =>
-        TypeSelect.copy(tree)(tree.qualifier, tree.name)
-      case tree: Projection =>
-        Projection.copy(tree)(tree.qualifier, tree.name)
-      case tree: Annotated =>
-        Annotated.copy(tree)(tree.arg, tree.annotation)
-      case tree: Singleton =>
-        Singleton.copy(tree)(transformTerm(tree.ref))
-      case tree: Refined =>
-        Refined.copy(tree)(transformTypeTree(tree.tpt), transformTrees(tree.refinements).asInstanceOf[List[Definition]])
-      case tree: Applied =>
-        Applied.copy(tree)(transformTypeTree(tree.tpt), transformTrees(tree.args))
-      case tree: MatchTypeTree =>
-        MatchTypeTree.copy(tree)(tree.bound.map(b => transformTypeTree(b)), transformTypeTree(tree.selector), transformTypeCaseDefs(tree.cases))
-      case tree: ByName =>
-        ByName.copy(tree)(transformTypeTree(tree.result))
-      case tree: LambdaTypeTree =>
-        LambdaTypeTree.copy(tree)(transformSubTrees(tree.tparams), transformTree(tree.body))(given tree.symbol.localContext)
-      case tree: TypeBind =>
-        TypeBind.copy(tree)(tree.name, tree.body)
-      case tree: TypeBlock =>
-        TypeBlock.copy(tree)(tree.aliases, tree.tpt)
-    }
-
-    def transformCaseDef(tree: CaseDef)(given ctx: Context): CaseDef = {
-      CaseDef.copy(tree)(transformTree(tree.pattern), tree.guard.map(transformTerm), transformTerm(tree.rhs))
-    }
-
-    def transformTypeCaseDef(tree: TypeCaseDef)(given ctx: Context): TypeCaseDef = {
-      TypeCaseDef.copy(tree)(transformTypeTree(tree.pattern), transformTypeTree(tree.rhs))
-    }
-
-    def transformStats(trees: List[Statement])(given ctx: Context): List[Statement] =
-      trees mapConserve (transformStatement(_))
-
-    def transformTrees(trees: List[Tree])(given ctx: Context): List[Tree] =
-      trees mapConserve (transformTree(_))
-
-    def transformTerms(trees: List[Term])(given ctx: Context): List[Term] =
-      trees mapConserve (transformTerm(_))
-
-    def transformTypeTrees(trees: List[TypeTree])(given ctx: Context): List[TypeTree] =
-      trees mapConserve (transformTypeTree(_))
-
-    def transformCaseDefs(trees: List[CaseDef])(given ctx: Context): List[CaseDef] =
-      trees mapConserve (transformCaseDef(_))
-
-    def transformTypeCaseDefs(trees: List[TypeCaseDef])(given ctx: Context): List[TypeCaseDef] =
-      trees mapConserve (transformTypeCaseDef(_))
-
-    def transformSubTrees[Tr <: Tree](trees: List[Tr])(given ctx: Context): List[Tr] =
-      transformTrees(trees).asInstanceOf[List[Tr]]
-
-  }
+  // TODO extract from Reflection
 
   /** Bind the `rhs` to a `val` and use it in `body` */
   def let(rhs: Term)(body: Ident => Term)(given ctx: Context): Term = {