Merge pull request #4473 from dotty-staging/tasty-to-quote

Add Term.toExpr in Tasty

Author: odersky

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

@@ -1,7 +1,9 @@
 package dotty.tools.dotc.quoted
 
 import dotty.tools.dotc.ast.tpd
+import dotty.tools.dotc.core.Contexts.Context
 import dotty.tools.dotc.core.Constants._
+import dotty.tools.dotc.core.quoted.PickledQuotes
 import dotty.tools.dotc.printing.RefinedPrinter
 
 import scala.quoted.Expr

compiler/src/dotty/tools/dotc/tasty/TastyImpl.scala

@@ -7,6 +7,8 @@ import dotty.tools.dotc.core.StdNames.nme
 import dotty.tools.dotc.core.Symbols.Symbol
 import dotty.tools.dotc.core.Decorators._
 import dotty.tools.dotc.core.quoted.PickledQuotes
+import dotty.tools.dotc.reporting.Reporter
+import dotty.tools.dotc.reporting.diagnostic.MessageContainer
 import dotty.tools.dotc.util.SourcePosition
 
 import scala.quoted
@@ -228,9 +230,40 @@ object TastyImpl extends scala.tasty.Tasty {
 
   type Term = tpd.Tree
 
-  def TermDeco(t: Term): AbstractTerm = new AbstractTerm {
-    def pos(implicit ctx: Context): Position = t.pos
-    def tpe(implicit ctx: Context): Types.Type = t.tpe
+  def TermDeco(tree: Term): AbstractTerm = new AbstractTerm {
+
+    def pos(implicit ctx: Context): Position = tree.pos
+
+    def tpe(implicit ctx: Context): Types.Type = tree.tpe
+
+    def toExpr[T: quoted.Type](implicit ctx: Context): quoted.Expr[T] = {
+      typecheck(ctx)
+      new quoted.Exprs.TastyTreeExpr(tree).asInstanceOf[quoted.Expr[T]]
+    }
+
+    private def typecheck[T: quoted.Type](ctx: Contexts.Context): Unit = {
+      implicit val ctx0: Contexts.FreshContext = ctx.fresh
+      ctx0.setTyperState(ctx0.typerState.fresh())
+      ctx0.typerState.setReporter(new Reporter {
+        def doReport(m: MessageContainer)(implicit ctx: Contexts.Context): Unit = ()
+      })
+      val tp = QuotedTypeDeco(implicitly[quoted.Type[T]]).toTasty
+      ctx0.typer.typed(tree, tp.tpe)
+      if (ctx0.reporter.hasErrors) {
+        val stack = new Exception().getStackTrace
+        def filter(elem: StackTraceElement) =
+          elem.getClassName.startsWith("dotty.tools.dotc.tasty.TastyImpl") ||
+          !elem.getClassName.startsWith("dotty.tools.dotc")
+        throw new scala.tasty.TastyTypecheckError(
+          s"""Error during tasty reflection while typing term
+             |term: ${tree.show}
+             |with expected type: ${tp.tpe.show}
+             |
+             |  ${stack.takeWhile(filter).mkString("\n  ")}
+           """.stripMargin
+        )
+      }
+    }
   }
 
   def termClassTag: ClassTag[Term] = implicitly[ClassTag[Term]]

library/src/scala/tasty/Tasty.scala

@@ -180,7 +180,9 @@ abstract class Tasty { tasty =>
 
   type Term <: Statement with Parent
 
-  trait AbstractTerm extends Typed with Positioned
+  trait AbstractTerm extends Typed with Positioned {
+    def toExpr[T: quoted.Type](implicit ctx: Context): quoted.Expr[T]
+  }
   implicit def TermDeco(t: Term): AbstractTerm
 
   implicit def termClassTag: ClassTag[Term]

library/src/scala/tasty/TastyTypecheckError.scala

@@ -0,0 +1,3 @@
+package scala.tasty
+
+class TastyTypecheckError(msg: String) extends Throwable

tests/neg/tasty-macro-assert/quoted_1.scala

@@ -0,0 +1,70 @@
+import scala.quoted._
+
+import scala.tasty.Universe
+
+object Asserts {
+
+  implicit class Ops[T](left: T) {
+    def ===(right: T): Boolean = left == right
+    def !==(right: T): Boolean = left != right
+  }
+
+  object Ops
+
+  inline def macroAssert(cond: Boolean): Unit =
+    ~impl('(cond))(Universe.compilationUniverse) // FIXME infer Universe.compilationUniverse within top level ~
+
+  def impl(cond: Expr[Boolean])(implicit u: Universe): Expr[Unit] = {
+    import u._
+    import u.tasty._
+
+    val tree = cond.toTasty
+
+    def isOps(tpe: TypeOrBounds): Boolean = tpe match {
+      case Type.SymRef(DefDef("Ops", _, _, _, _), _) => true // TODO check that the parent is Asserts
+      case _ => false
+    }
+
+    object OpsTree {
+      def unapply(arg: Term): Option[Term] = arg match {
+        case Term.Apply(Term.TypeApply(term, _), left :: Nil) if isOps(term.tpe) =>
+          Some(left)
+        case _ => None
+      }
+    }
+
+    tree match {
+      case Term.Apply(Term.Select(OpsTree(left), op, _), right :: Nil) =>
+        '(assertTrue(~left.toExpr[Boolean])) // Buggy code. To generate the errors
+      case _ =>
+        '(assertTrue(~cond))
+    }
+
+  }
+
+  def assertEquals[T](left: T, right: T): Unit = {
+    if (left != right) {
+      println(
+        s"""Error left did not equal right:
+           |  left  = $left
+           |  right = $right""".stripMargin)
+    }
+
+  }
+
+  def assertNotEquals[T](left: T, right: T): Unit = {
+    if (left == right) {
+      println(
+        s"""Error left was equal to right:
+           |  left  = $left
+           |  right = $right""".stripMargin)
+    }
+
+  }
+
+  def assertTrue(cond: Boolean): Unit = {
+    if (!cond)
+      println("Condition was false")
+  }
+
+}

tests/neg/tasty-macro-assert/quoted_2.scala

@@ -0,0 +1,12 @@
+
+import Asserts._
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    macroAssert(true === "cde")
+    macroAssert("acb" === "cde") // error
+    macroAssert(false !== "acb")
+    macroAssert("acb" !== "acb") // error
+  }
+
+}

tests/run/tasty-macro-assert.check

@@ -1,7 +1,7 @@
 Condition was false
 Error left did not equal right:
-  left  = Term.Literal(Constant.String("acb"))
-  right = Term.Literal(Constant.String("cde"))
+  left  = acb
+  right = cde
 Error left was equal to right:
-  left  = Term.Literal(Constant.String("acb"))
-  right = Term.Literal(Constant.String("acb"))
+  left  = acb
+  right = acb

tests/run/tasty-macro-assert/quoted_1.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import dotty.tools.dotc.quoted.Toolbox._
 
 import scala.tasty.Universe
 
@@ -36,12 +35,9 @@ object Asserts {
 
     tree match {
       case Term.Apply(Term.Select(OpsTree(left), op, _), right :: Nil) =>
-        // FIXME splice the threes directly
-        val lExpr = left.show.toExpr
-        val rExpr = right.show.toExpr
         op match {
-          case "===" => '(assertEquals(~lExpr, ~rExpr))
-          case "!==" => '(assertNotEquals(~lExpr, ~rExpr))
+          case "===" => '(assertEquals(~left.toExpr[Any], ~right.toExpr[Any]))
+          case "!==" => '(assertNotEquals(~left.toExpr[Any], ~right.toExpr[Any]))
         }
       case _ =>
         '(assertTrue(~cond))