Improve Expr.toString and Type.toString

We now capture the context in each `Expr` and `Type` instead of the
`Scope`. This context can be used to compute the `Scope`.

Author: nicolasstucki

compiler/src/dotty/tools/dotc/quoted/PickledQuotes.scala

@@ -197,18 +197,18 @@ object PickledQuotes {
   }
 
   def reifyTypeHoleArgs(args: List[Tree])(using Context): List[scala.quoted.Type[?]] =
-    args.map(arg => new TypeImpl(arg, SpliceScope.getCurrent))
+    args.map(arg => new TypeImpl(arg))
 
   def reifyExprHoleV1Args(args: List[Tree])(using Context): List[ExprHole.ArgV1] =
     args.map { arg =>
-      if arg.isTerm then (q: Quotes) ?=> new ExprImpl(arg, SpliceScope.getCurrent)
-      else new TypeImpl(arg, SpliceScope.getCurrent)
+      if arg.isTerm then (q: Quotes) ?=> new ExprImpl(arg)
+      else new TypeImpl(arg)
     }
 
   def reifyExprHoleV2Args(args: List[Tree])(using Context): List[ExprHole.ArgV2] =
     args.map { arg =>
-      if arg.isTerm then new ExprImpl(arg, SpliceScope.getCurrent)
-      else new TypeImpl(arg, SpliceScope.getCurrent)
+      if arg.isTerm then new ExprImpl(arg)
+      else new TypeImpl(arg)
     }
 
   // TASTY picklingtests/pos/quoteTest.scala

compiler/src/dotty/tools/dotc/transform/Splicer.scala

@@ -237,11 +237,11 @@ object Splicer {
           case Inlined(EmptyTree, _, quoted) => quoted
           case _ => quoted
         }
-        new ExprImpl(Inlined(EmptyTree, Nil, QuoteUtils.changeOwnerOfTree(quoted1, ctx.owner)).withSpan(quoted1.span), SpliceScope.getCurrent)
+        new ExprImpl(Inlined(EmptyTree, Nil, QuoteUtils.changeOwnerOfTree(quoted1, ctx.owner)).withSpan(quoted1.span))
 
       // Interpret level -1 `Type.of[T]`
       case Apply(TypeApply(fn, quoted :: Nil), _) if fn.symbol == defn.QuotedTypeModule_of =>
-        new TypeImpl(QuoteUtils.changeOwnerOfTree(quoted, ctx.owner), SpliceScope.getCurrent)
+        new TypeImpl(QuoteUtils.changeOwnerOfTree(quoted, ctx.owner))
 
       case _ =>
         super.interpretTree(tree)

compiler/src/scala/quoted/runtime/impl/ExprImpl.scala

@@ -2,6 +2,7 @@ package scala.quoted
 package runtime.impl
 
 import dotty.tools.dotc.ast.tpd
+import dotty.tools.dotc.core.Contexts.Context
 
 /** An Expr backed by a tree. Only the current compiler trees are allowed.
  *
@@ -10,7 +11,10 @@ import dotty.tools.dotc.ast.tpd
  *
  *  May contain references to code defined outside this Expr instance.
  */
-final class ExprImpl(val tree: tpd.Tree, val scope: Scope) extends Expr[Any] {
+final class ExprImpl(val tree: tpd.Tree)(using val ctx: Context) extends Expr[Any]:
+
+  def scope: Scope = SpliceScope.getCurrent
+
   override def equals(that: Any): Boolean = that match {
     case that: ExprImpl =>
       // Expr are wrappers around trees, therefore they are equals if their trees are equal.
@@ -21,5 +25,4 @@ final class ExprImpl(val tree: tpd.Tree, val scope: Scope) extends Expr[Any] {
 
   override def hashCode(): Int = tree.hashCode()
 
-  override def toString: String = "'{ ... }"
-}
+  override def toString(): String = QuotesImpl.showDecompiledTree(tree)

compiler/src/scala/quoted/runtime/impl/QuoteMatcher.scala

@@ -462,7 +462,7 @@ object QuoteMatcher {
     val matched: Matching = Some(Tuple())
 
     def matched(tree: Tree)(using Context): Matching =
-      Some(Tuple1(new ExprImpl(tree, SpliceScope.getCurrent)))
+      Some(Tuple1(new ExprImpl(tree)))
 
     extension (self: Matching)
       def asOptionOfTuple: Option[Tuple] = self

compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala

@@ -105,7 +105,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
             case _ => false
         def asExpr: scala.quoted.Expr[Any] =
           if self.isExpr then
-            new ExprImpl(self, SpliceScope.getCurrent)
+            new ExprImpl(self)
           else self match
             case TermTypeTest(self) => throw new Exception("Expected an expression. This is a partially applied Term. Try eta-expanding the term first.")
             case _ => throw new Exception("Expected a Term but was: " + Printer.TreeStructure.show(self))
@@ -377,11 +377,11 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
     given TermMethods: TermMethods with
       extension (self: Term)
         def seal: scala.quoted.Expr[Any] =
-          if self.isExpr then new ExprImpl(self, SpliceScope.getCurrent)
+          if self.isExpr then new ExprImpl(self)
           else throw new Exception("Cannot seal a partially applied Term. Try eta-expanding the term first.")
 
         def sealOpt: Option[scala.quoted.Expr[Any]] =
-          if self.isExpr then Some(new ExprImpl(self, SpliceScope.getCurrent))
+          if self.isExpr then Some(new ExprImpl(self))
           else None
 
         def tpe: TypeRepr = self.tpe.widenSkolem
@@ -1722,7 +1722,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
         def seal: scala.quoted.Type[_] = self.asType
 
         def asType: scala.quoted.Type[?] =
-          new TypeImpl(Inferred(self), SpliceScope.getCurrent)
+          new TypeImpl(Inferred(self))
 
         def =:=(that: TypeRepr): Boolean = self =:= that
         def <:<(that: TypeRepr): Boolean = self <:< that
@@ -3048,19 +3048,19 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
 
   def unpickleExpr[T](pickled: String | List[String], typeHole: (Int, Seq[Any]) => scala.quoted.Type[?], termHole: (Int, Seq[Any], scala.quoted.Quotes) => scala.quoted.Expr[?]): scala.quoted.Expr[T] =
     val tree = PickledQuotes.unpickleTerm(pickled, PickledQuotes.TypeHole.V1(typeHole), PickledQuotes.ExprHole.V1(termHole))
-    new ExprImpl(tree, SpliceScope.getCurrent).asInstanceOf[scala.quoted.Expr[T]]
+    new ExprImpl(tree).asInstanceOf[scala.quoted.Expr[T]]
 
   def unpickleExprV2[T](pickled: String | List[String], types: Seq[Type[?]], termHole: Null | ((Int, Seq[Type[?] | Expr[Any]], Quotes) => Expr[?])): scala.quoted.Expr[T] =
     val tree = PickledQuotes.unpickleTerm(pickled, PickledQuotes.TypeHole.V2(types), PickledQuotes.ExprHole.V2(termHole))
-    new ExprImpl(tree, SpliceScope.getCurrent).asInstanceOf[scala.quoted.Expr[T]]
+    new ExprImpl(tree).asInstanceOf[scala.quoted.Expr[T]]
 
   def unpickleType[T <: AnyKind](pickled: String | List[String], typeHole: (Int, Seq[Any]) => scala.quoted.Type[?], termHole: (Int, Seq[Any], scala.quoted.Quotes) => scala.quoted.Expr[?]): scala.quoted.Type[T] =
     val tree = PickledQuotes.unpickleTypeTree(pickled, PickledQuotes.TypeHole.V1(typeHole))
-    new TypeImpl(tree, SpliceScope.getCurrent).asInstanceOf[scala.quoted.Type[T]]
+    new TypeImpl(tree).asInstanceOf[scala.quoted.Type[T]]
 
   def unpickleTypeV2[T <: AnyKind](pickled: String | List[String], types: Seq[Type[?]]): scala.quoted.Type[T] =
     val tree = PickledQuotes.unpickleTypeTree(pickled, PickledQuotes.TypeHole.V2(types))
-    new TypeImpl(tree, SpliceScope.getCurrent).asInstanceOf[scala.quoted.Type[T]]
+    new TypeImpl(tree).asInstanceOf[scala.quoted.Type[T]]
 
   object ExprMatch extends ExprMatchModule:
     def unapply[TypeBindings <: Tuple, Tup <: Tuple](scrutinee: scala.quoted.Expr[Any])(using pattern: scala.quoted.Expr[Any]): Option[Tup] =

compiler/src/scala/quoted/runtime/impl/TypeImpl.scala

@@ -2,9 +2,13 @@ package scala.quoted
 package runtime.impl
 
 import dotty.tools.dotc.ast.tpd
+import dotty.tools.dotc.core.Contexts.Context
 
 /** Quoted type (or kind) `T` backed by a tree */
-final class TypeImpl(val typeTree: tpd.Tree, val scope: Scope) extends Type[?] {
+final class TypeImpl(val typeTree: tpd.Tree)(using val ctx: Context) extends Type[?]:
+
+  def scope: Scope = SpliceScope.getCurrent
+
   override def equals(that: Any): Boolean = that match {
     case that: TypeImpl => typeTree ==
       // TastyTreeExpr are wrappers around trees, therefore they are equals if their trees are equal.
@@ -15,5 +19,4 @@ final class TypeImpl(val typeTree: tpd.Tree, val scope: Scope) extends Type[?] {
 
   override def hashCode(): Int = typeTree.hashCode()
 
-  override def toString: String = "Type.of[...]"
-}
+  override def toString: String = QuotesImpl.showDecompiledTree(typeTree)

tests/pos-with-compiler-cc/dotc/quoted/PickledQuotes.scala

@@ -196,18 +196,18 @@ object PickledQuotes {
   }
 
   def reifyTypeHoleArgs(args: List[Tree])(using Context): List[scala.quoted.Type[?]] =
-    args.map(arg => new TypeImpl(arg, SpliceScope.getCurrent))
+    args.map(arg => new TypeImpl(arg)(using ctx.detach))
 
   def reifyExprHoleV1Args(args: List[Tree])(using Context): List[ExprHole.ArgV1] =
     args.map { arg =>
-      if arg.isTerm then (q: Quotes) ?=> new ExprImpl(arg, SpliceScope.getCurrent)
-      else new TypeImpl(arg, SpliceScope.getCurrent)
+      if arg.isTerm then (q: Quotes) ?=> new ExprImpl(arg)(using ctx.detach)
+      else new TypeImpl(arg)(using ctx.detach)
     }
 
   def reifyExprHoleV2Args(args: List[Tree])(using Context): List[ExprHole.ArgV2] =
     args.map { arg =>
-      if arg.isTerm then new ExprImpl(arg, SpliceScope.getCurrent)
-      else new TypeImpl(arg, SpliceScope.getCurrent)
+      if arg.isTerm then new ExprImpl(arg)(using ctx.detach)
+      else new TypeImpl(arg)(using ctx.detach)
     }
 
   // TASTY picklingtests/pos/quoteTest.scala

tests/pos-with-compiler-cc/dotc/transform/Splicer.scala

@@ -241,11 +241,11 @@ object Splicer {
           case Inlined(EmptyTree, _, quoted) => quoted
           case _ => quoted
         }
-        new ExprImpl(Inlined(EmptyTree, Nil, QuoteUtils.changeOwnerOfTree(quoted1, ctx.owner)).withSpan(quoted1.span), SpliceScope.getCurrent)
+        new ExprImpl(Inlined(EmptyTree, Nil, QuoteUtils.changeOwnerOfTree(quoted1, ctx.owner)).withSpan(quoted1.span))(using ctx.detach)
 
       // Interpret level -1 `Type.of[T]`
       case Apply(TypeApply(fn, quoted :: Nil), _) if fn.symbol == defn.QuotedTypeModule_of =>
-        new TypeImpl(QuoteUtils.changeOwnerOfTree(quoted, ctx.owner), SpliceScope.getCurrent)
+        new TypeImpl(QuoteUtils.changeOwnerOfTree(quoted, ctx.owner))(using ctx.detach)
 
       case _ =>
         super.interpretTree(tree)

tests/run-macros/Expr-toString.check

@@ -0,0 +1,4 @@
+1
+"abc"
+scala.Predef.println("abc")
+while (true) ()

tests/run-macros/Expr-toString/Macros_1.scala

@@ -0,0 +1,6 @@
+import scala.quoted.*
+
+inline def showToString(inline x: Any): String = ${ macroImpl('x) }
+
+private def macroImpl(x: Expr[Any])(using Quotes): Expr[String] =
+  Expr(x.toString)

tests/run-macros/Expr-toString/Test_2.scala

@@ -0,0 +1,5 @@
+@main def Test() =
+  println(showToString(1))
+  println(showToString("abc"))
+  println(showToString(println("abc")))
+  println(showToString { while true do () } )

tests/run-macros/Type-toString.check

@@ -0,0 +1,7 @@
+1
+"abc"
+scala.Int
+scala.collection.immutable.List[scala.Int]
+java.lang.Object {
+  def foo: scala.Int
+}

tests/run-macros/Type-toString/Macros_1.scala

@@ -0,0 +1,6 @@
+import scala.quoted.*
+
+inline def showToString[T]: String = ${ macroImpl[T] }
+
+private def macroImpl[T: Type](using Quotes): Expr[String] =
+  Expr(Type.of[T].toString)

tests/run-macros/Type-toString/Test_2.scala

@@ -0,0 +1,6 @@
+@main def Test() =
+  println(showToString[1])
+  println(showToString["abc"])
+  println(showToString[Int])
+  println(showToString[List[Int]])
+  println(showToString[Object { def foo: Int }])