Add underlying term to know the static value of some ident

Author: nicolasstucki

compiler/src/dotty/tools/dotc/ast/tpd.scala

@@ -913,7 +913,11 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     def outerSelect(levels: Int, tp: Type)(implicit ctx: Context): Tree =
       untpd.Select(tree, OuterSelectName(EmptyTermName, levels)).withType(SkolemType(tp))
 
-    def underlyingArgument(implicit ctx: Context): Tree = mapToUnderlying.transform(tree)
+    /** Replace Inlined nodes and InlineProxy references to underlying arguments */
+    def underlyingArgument(implicit ctx: Context): Tree = mapToUnderlyingArgument.transform(tree)
+
+    /** Replace Ident nodes references to the underlying tree that defined them */
+    def underlying(implicit ctx: Context): Tree = mapToUnderlying.transform(tree)
 
     // --- Higher order traversal methods -------------------------------
 
@@ -942,7 +946,7 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   }
 
   /** Map Inlined nodes, InlineProxy references and Synthetic val references to underlying arguments */
-  object mapToUnderlying extends TreeMap {
+  object mapToUnderlyingArgument extends TreeMap {
     override def transform(tree: Tree)(implicit ctx: Context): Tree = tree match {
       case tree: Ident if tree.symbol.is(InlineProxy) || (tree.symbol.is(Synthetic) && !tree.symbol.owner.isClass) =>
         tree.symbol.defTree match {
@@ -955,6 +959,23 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     }
   }
 
+  /** Map Ident nodes references to underlying tree that defined them.
+   *  Also drops Inline and Block with no statements
+   */
+  object mapToUnderlying extends TreeMap {
+    override def transform(tree: Tree)(implicit ctx: Context): Tree = tree match {
+      case tree: Ident if !tree.symbol.owner.isClass =>
+        tree.symbol.defTree match {
+          case defTree: ValOrDefDef => transform(defTree.rhs)
+          case _ => tree
+        }
+      case Inlined(_, _, arg) => transform(arg)
+      case Block(Nil, arg) => transform(arg)
+      case NamedArg(_, arg) => transform(arg)
+      case tree => super.transform(tree)
+    }
+  }
+
   implicit class ListOfTreeDecorator(val xs: List[tpd.Tree]) extends AnyVal {
     def tpes: List[Type] = xs map (_.tpe)
   }

compiler/src/dotty/tools/dotc/tastyreflect/TreeOpsImpl.scala

@@ -186,12 +186,11 @@ trait TreeOpsImpl extends scala.tasty.reflect.TreeOps with TastyCoreImpl with He
   // ----- Terms ----------------------------------------------------
 
   def TermDeco(term: Term): TermAPI = new TermAPI {
+    import tpd._
     def pos(implicit ctx: Context): Position = term.pos
     def tpe(implicit ctx: Context): Type = term.tpe
-    def underlyingArgument(implicit ctx: Context): Term = {
-      import tpd._
-      term.underlyingArgument
-    }
+    def underlyingArgument(implicit ctx: Context): Term = term.underlyingArgument
+    def underlying(implicit ctx: Context): Term = term.underlying
   }
 
   object IsTerm extends IsTermExtractor {

compiler/test/dotc/run-test-pickling.blacklist

@@ -59,6 +59,7 @@ t7374
 t7859
 t8133
 t8133b
+tasty-argument-tree-1
 tasty-custom-show
 tasty-definitions-1
 tasty-definitions-2
@@ -91,4 +92,5 @@ typelevel-patmat.scala
 typelevel.scala
 typelevel1.scala
 typelevel3.scala
-xml-interpolation
+xml-interpolation-1
+xml-interpolation-2

library/src/scala/tasty/reflect/TreeOps.scala

@@ -156,6 +156,7 @@ trait TreeOps extends TastyCore {
     def tpe(implicit ctx: Context): Type
     def pos(implicit ctx: Context): Position
     def underlyingArgument(implicit ctx: Context): Term
+    def underlying(implicit ctx: Context): Term
   }
   implicit def TermDeco(term: Term): TermAPI
 

tests/run/tasty-argument-tree-1.check

@@ -0,0 +1,33 @@
+
+tree: Term.Literal(Constant.Int(3))
+tree deref. vals: Term.Literal(Constant.Int(3))
+
+tree: Term.Ident("v")
+tree deref. vals: Term.Literal(Constant.Int(1))
+
+tree: Term.Ident("x")
+tree deref. vals: Term.Literal(Constant.Int(2))
+
+tree: Term.Ident("l")
+tree deref. vals: Term.Literal(Constant.Int(3))
+
+tree: Term.Ident("a")
+tree deref. vals: Term.Ident("a")
+
+tree: Term.Ident("x")
+tree deref. vals: Term.Ident("b")
+
+tree: Term.Ident("vv")
+tree deref. vals: Term.Literal(Constant.Int(1))
+
+tree: Term.Ident("x")
+tree deref. vals: Term.Literal(Constant.Int(1))
+
+tree: Term.Ident("vd")
+tree deref. vals: Term.Literal(Constant.Int(2))
+
+tree: Term.Ident("x")
+tree deref. vals: Term.Literal(Constant.Int(2))
+
+tree: Term.Ident("x")
+tree deref. vals: Term.Apply(Term.TypeApply(Term.Select(Term.Ident("Tuple2"), "apply", Some(Signature(List(java.lang.Object, java.lang.Object), scala.Tuple2))), List(TypeTree.Synthetic(), TypeTree.Synthetic())), List(Term.Literal(Constant.Int(1)), Term.Literal(Constant.Int(2))))

tests/run/tasty-argument-tree-1/quoted_1.scala

@@ -0,0 +1,17 @@
+import scala.quoted._
+import scala.tasty._
+
+object Macros {
+
+  inline def inspect[T](x: T): Unit = ~impl('(x))
+
+  def impl[T](x: Expr[T])(implicit tasty: Tasty): Expr[Unit] = {
+    import tasty._
+    val tree = x.toTasty
+    '{
+      println()
+      println("tree: " + ~tree.show.toExpr)
+      println("tree deref. vals: " + ~tree.underlying.show.toExpr)
+    }
+  }
+}

tests/run/tasty-argument-tree-1/quoted_2.scala

@@ -0,0 +1,31 @@
+
+import Macros.inspect
+
+object Test {
+  val a: Int = 4
+  def b: Int = 5
+
+  def main(args: Array[String]): Unit = {
+    val v: Int = 1
+    def d: Int = 2
+    lazy val l: Int = 3
+    inspect(3)
+    inspect(v)
+    inspect(d)
+    inspect(l)
+    inspect(a)
+    inspect(b)
+
+    val vv = v
+    def dv = v
+    val vd = d
+    def dd = d
+    inspect(vv)
+    inspect(dv)
+    inspect(vd)
+    inspect(dd)
+
+    inspect((dv, vd))
+
+  }
+}

tests/run/xml-interpolation/Test_2.scala renamed to tests/run/xml-interpolation-1/Test_2.scala

@@ -0,0 +1,27 @@
+import XmlQuote._
+
+object Test {
+  def main(args: Array[String]): Unit = {
+
+    assert(xml"Hello Allan!" == Xml("Hello Allan!", Nil))
+
+    val name = new Object{}
+    assert(xml"Hello $name!" == Xml("Hello ??!", List(name)))
+
+    val ctx0 = new StringContext("Hello !")
+    assert(ctx0.xml() == Xml("Hello !", Nil))
+    assert(new SCOps(ctx0).xml() == Xml("Hello !", Nil))
+
+    val ctx1 = new StringContext("Hello ", "!")
+    assert(ctx1.xml(name) == Xml("Hello ??!", List(name)))
+    assert(new SCOps(ctx1).xml(name) == Xml("Hello ??!", List(name)))
+
+    val hello: String = "Hello "
+    val ctx2 = new StringContext(hello, "!")
+    assert(ctx2.xml(name) == Xml("Hello ??!", List(name)))
+    assert(new SCOps(ctx2).xml(name) == Xml("Hello ??!", List(name)))
+
+    val args = Seq(name)
+    assert(new SCOps(ctx2).xml(args: _*) == Xml("Hello ??!", List(name)))
+  }
+}

tests/run/xml-interpolation/XmlQuote_1.scala renamed to tests/run/xml-interpolation-1/XmlQuote_1.scala

@@ -0,0 +1,66 @@
+import scala.quoted._
+
+import scala.tasty.Tasty
+
+import scala.language.implicitConversions
+
+case class Xml(parts: String, args: List[Any])
+
+object XmlQuote {
+
+  class SCOps(ctx: => StringContext) {
+    inline def xml(args: Any*): Xml = ~XmlQuote.impl('(this), '(args))
+  }
+  implicit inline def SCOps(ctx: => StringContext): SCOps = new SCOps(ctx)
+
+  def impl(receiver: Expr[SCOps], args: Expr[Seq[Any]])
+          (implicit tasty: Tasty): Expr[Xml] = {
+    import tasty._
+    import Term._
+
+    // for debugging purpose
+    def pp(tree: Tree): Unit = {
+      println(tree.show)
+      println(tasty.showSourceCode.showTree(tree))
+    }
+
+    def isSCOpsConversion(tree: Term) =
+      tree.symbol.fullName == "XmlQuote$.SCOps" ||
+      tree.symbol.fullName == "XmlQuote$.SCOps.<init>"
+
+    def isStringContextApply(tree: Term) =
+      tree.symbol.fullName == "scala.StringContext$.apply" ||
+      tree.symbol.fullName == "scala.StringContext.<init>"
+
+    // XmlQuote.SCOps(StringContext.apply([p0, ...]: String*)
+    val parts: List[String] = receiver.toTasty.underlying match {
+      case Apply(conv, List(ctx1)) if isSCOpsConversion(conv) =>
+        ctx1 match {
+          case Apply(fun, List(Typed(Repeated(values), _))) if isStringContextApply(fun) =>
+            values.iterator.map {
+              case Literal(Constant.String(value)) => value
+              case _ => QuoteError("Expected statically known String")
+            }.toList
+          case _ => QuoteError("Expected statically known StringContext")
+        }
+      case _ =>
+        QuoteError("Expected statically known SCOps")
+    }
+
+    // [a0, ...]: Any*
+    val args2: Expr[List[Any]] = args.toTasty.underlyingArgument match {
+      case Typed(Repeated(args0), _) => // statically known args, make list directly
+        def liftListOfAny(lst: List[Expr[Any]]): Expr[List[Any]] = lst match {
+          case x :: xs  => '{ ~x :: ~liftListOfAny(xs) }
+          case Nil => '(Nil)
+        }
+        liftListOfAny(args0.map(_.toExpr[Any]))
+      case _ =>
+        '((~args).toList)
+
+    }
+
+    val string = parts.mkString("??")
+    '(new Xml(~string.toExpr, ~args2))
+  }
+}