Fix #9812: Do not widen types during quote reification

Author: nicolasstucki

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

@@ -168,7 +168,7 @@ class ReifyQuotes extends MacroTransform {
           else
             val tpe =
               if originalTp =:= defn.NilModule.termRef then originalTp // Workaround #4987
-              else originalTp.widen.dealias
+              else originalTp.dealias
             ref(defn.Unpickler_unpickleExpr).appliedToType(tpe)
         val pickledQuoteStrings = liftList(PickledQuotes.pickleQuote(body).map(x => Literal(Constant(x))), defn.StringType)
         val splicesList = liftList(splices, defn.FunctionType(1).appliedTo(defn.SeqType.appliedTo(defn.AnyType), defn.AnyType))

tests/pos-macros/i9812.scala

@@ -0,0 +1,8 @@
+// compile with -Ycheck:reifyQuotes -Ystop-after:reifyQuotes
+import quoted._
+
+sealed abstract class SomeEnum
+object SomeEnum:
+  final val Foo = new SomeEnum {}
+
+def quoteFoo: QuoteContext ?=> Expr[SomeEnum.Foo.type] = '{SomeEnum.Foo}