Merge pull request #10110 from dotty-staging/use-canonical-undelying-type

Use canonical underlying type reference

Author: nicolasstucki

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

@@ -77,7 +77,6 @@ class ReifyQuotes extends MacroTransform {
       case tree: RefTree if !Inliner.inInlineMethod =>
         assert(!tree.symbol.isQuote)
         assert(!tree.symbol.isExprSplice)
-        assert(!tree.symbol.isTypeSplice)
       case _ : TypeDef =>
         assert(!tree.symbol.hasAnnotation(defn.InternalQuoted_QuoteTypeTagAnnot),
           s"${tree.symbol} should have been removed by PickledQuotes because it has a @quoteTypeTag")
@@ -210,16 +209,15 @@ class ReifyQuotes extends MacroTransform {
      *  are in the body of an inline method.
      */
      protected def transformSpliceType(body: Tree, splice: Select)(using Context): Tree =
-      if (level > 1) {
+      if level > 1 then
         val body1 = nested(isQuote = false).transform(body)(using spliceContext)
         cpy.Select(splice)(body1, splice.name)
-      }
-      else {
-        assert(level == 1, "unexpected top splice outside quote")
+      else if level == 1 then
         val (body1, quotes) = nested(isQuote = false).splitSplice(body)(using spliceContext)
         val tpe = outer.embedded.getHoleType(body, splice)
         makeHole(splice.isTerm, body1, quotes, tpe).withSpan(splice.span)
-      }
+      else
+        splice
 
     /** Transforms the contents of a nested splice
      *  Assuming

tests/neg-macros/i6997.scala

@@ -2,7 +2,7 @@
 import scala.quoted._
 class Foo {
   def mcrImpl(body: Expr[Any])(using t: Type[_ <: Any])(using ctx: QuoteContext): Expr[Any] = '{
-    val tmp = ???.asInstanceOf[$t] // error // error
+    val tmp = ???.asInstanceOf[t.Underlying] // error // error
     tmp
   }
 }

tests/neg-macros/i7048e.scala

@@ -16,18 +16,18 @@ abstract class Test {
       import t.given
       println(summon[Type[t.T]].show)
       // val r = '{Option.empty[t.T]} // access to value t from wrong staging level
-      val r2 = '{Option.empty[${t.T}]} // works
+      val r2 = '{Option.empty[t.T.Underlying]} // works
     }
 
     {
-      val r1 = '{Option.empty[${T}]} // works
-      val r2 = '{Option.empty[List[${T}]]} // works
-      val r3 = '{summon[Type[${T}]]} // error: is not stable
-      val r4 = '{summon[${T} <:< Any]} // error: is not stable
+      val r1 = '{Option.empty[T.Underlying]} // works
+      val r2 = '{Option.empty[List[T.Underlying]]} // works
+      val r3 = '{summon[Type[T.Underlying]]} // error: is not stable
+      val r4 = '{summon[T.Underlying <:< Any]} // error: is not stable
     }
 
     {
-      val s = '{Option.empty[${T}]} // works
+      val s = '{Option.empty[T.Underlying]} // works
       val r = '{identity($s)} // works
       val r2 = '{identity(${s: Expr[Option[T]]})} // error // error : is not stable
     }

tests/pos-macros/i4023c/Macro_1.scala

@@ -1,5 +1,5 @@
 import scala.quoted._
 object Macro {
   inline def ff[T](x: T): T = ${ impl('x) }
-  def impl[T](x: Expr[T])(implicit t: Type[T], qctx: QuoteContext): Expr[T] = '{ $x: $t }
+  def impl[T](x: Expr[T])(implicit t: Type[T], qctx: QuoteContext): Expr[T] = '{ $x: T }
 }

tests/pos-macros/i4774a.scala

@@ -3,7 +3,7 @@ import scala.quoted._
 
 object Test {
   def loop[T](x: Expr[T])(implicit t: Type[T], qctx: QuoteContext): Expr[T] = '{
-    val y: $t = $x
+    val y: T = $x
     ${loop('y)}
   }
 }

tests/neg-macros/i4774b.scala renamed to tests/pos-macros/i4774b.scala

@@ -3,8 +3,8 @@ import scala.quoted._
 
 object Test {
   def loop[T](x: Expr[T])(implicit t: Type[T], qctx: QuoteContext): Expr[T] = '{
-    val y: $t = $x;
-    ${loop[$t]( // error
+    val y: t.Underlying = $x;
+    ${loop[t.Underlying](
       'y
     )}
   }

tests/pos-macros/i6210/Macros_1.scala

@@ -7,8 +7,8 @@ object Macro {
   def impl[A : Type, B : Type](using QuoteContext): Expr[Any] = {
     val t = Type[Map[A, B]]
     '{
-      new Object().asInstanceOf[$t]
-      ???.asInstanceOf[$t]
+      new Object().asInstanceOf[t.Underlying]
+      ???.asInstanceOf[t.Underlying]
     }
   }
 }

tests/pos-macros/i7048e.scala

@@ -16,18 +16,18 @@ abstract class Test {
       import t.given
       println(summon[Type[t.T]].show)
       // val r = '{Option.empty[t.T]} // access to value t from wrong staging level
-      val r2 = '{Option.empty[${t.T}]}
+      val r2 = '{Option.empty[t.T.Underlying]}
     }
 
     {
-      val r1 = '{Option.empty[${T}]} // works
-      val r2 = '{Option.empty[List[${T}]]} // works
-      // val r3 = '{summon[Type[${T}]]} // access to Test.this from wrong staging level
-      val r4 = '{summon[${T} <:< Any]}
+      val r1 = '{Option.empty[T.Underlying]} // works
+      val r2 = '{Option.empty[List[T.Underlying]]} // works
+      // val r3 = '{summon[Type[T.Underlying]]} // access to Test.this from wrong staging level
+      val r4 = '{summon[T.Underlying <:< Any]}
     }
 
     {
-      val s = '{Option.empty[${T}]}
+      val s = '{Option.empty[T.Underlying]}
       val r = '{identity($s)} // works
       val r2 = '{identity(${s: Expr[Option[T]]})}
     }

tests/pos-macros/i7405.scala

@@ -6,7 +6,7 @@ class Foo {
       val x: X = ???
       ${
         val t: Type[X] = Type[X] // Level 0
-        '{ val y: $t = x }
+        '{ val y: t.Underlying = x }
       }
     }
   }

tests/pos-macros/i7405b.scala

@@ -11,7 +11,8 @@ class Foo {
       type Z = x.Y
       ${
         val t: Type[Z] = Type[Z]
-        '{ val y: $t = x.y }
+        '{ val y: Z = x.y }
+        '{ val y: t.Underlying = x.y }
       }
     }
   }