From 79cbafcddc740ab4df1d4cc0f57b7d54dcd36007 Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Tue, 27 Apr 2021 09:13:30 +0200
Subject: [PATCH] Fix internal definition of `Unapply`

Remove old workaround for `Unapply`.

Users may see an extra `Typed` in the trees of patterns

Fixes #12221
---
 .../quoted/runtime/impl/QuotesImpl.scala      | 28 +++++++------------
 .../runtime/impl/printers/SourceCode.scala    |  3 ++
 library/src/scala/quoted/Quotes.scala         |  2 +-
 tests/run-staging/i5161.check                 |  2 +-
 4 files changed, 15 insertions(+), 20 deletions(-)

diff --git a/compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala b/compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala
index 6fdf2225bbdf..fed05b4492fd 100644
--- a/compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala
+++ b/compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala
@@ -333,13 +333,11 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
 
     object TermTypeTest extends TypeTest[Tree, Term]:
       def unapply(x: Tree): Option[Term & x.type] = x match
-        case _ if UnapplyTypeTest.unapply(x).isDefined => None
-        case _: tpd.PatternTree => None
-        case x: (tpd.Tree & x.type) if x.isTerm => Some(x)
+        case x: tpd.PatternTree => None
         case x: (tpd.SeqLiteral & x.type) => Some(x)
         case x: (tpd.Inlined & x.type) => Some(x)
         case x: (tpd.NamedArg & x.type) => Some(x)
-        case _ => None
+        case _ => if x.isTerm then Some(x) else None
     end TermTypeTest
 
     object Term extends TermModule:
@@ -1424,14 +1422,12 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
       end extension
     end BindMethods
 
-    type Unapply = tpd.UnApply | tpd.Typed // tpd.Typed containing a tpd.UnApply as expression
+    type Unapply = tpd.UnApply
 
     object UnapplyTypeTest extends TypeTest[Tree, Unapply]:
-      def unapply(x: Tree): Option[Unapply & x.type] =
-        x match // keep in sync with UnapplyMethodsImpl.selfUnApply
-          case x: (tpd.UnApply & x.type) => Some(x)
-          case x: (tpd.Typed & x.type) if x.expr.isInstanceOf[tpd.UnApply] => Some(x)
-          case _ => None
+      def unapply(x: Tree): Option[Unapply & x.type] = x match
+        case x: (tpd.UnApply & x.type) => Some(x)
+        case _ => None
     end UnapplyTypeTest
 
     object Unapply extends UnapplyModule:
@@ -1443,14 +1439,10 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
 
     given UnapplyMethods: UnapplyMethods with
       extension (self: Unapply)
-        def fun: Term = selfUnApply(self).fun
-        def implicits: List[Term] = selfUnApply(self).implicits
-        def patterns: List[Tree] = effectivePatterns(selfUnApply(self).patterns)
-      end extension
-      private def selfUnApply(self: Unapply): tpd.UnApply =
-        self match // keep in sync with UnapplyTypeTest
-          case self: tpd.UnApply => self
-          case self: tpd.Typed => self.expr.asInstanceOf[tpd.UnApply]
+        def fun: Term = self.fun
+        def implicits: List[Term] = self.implicits
+        def patterns: List[Tree] = effectivePatterns(self.patterns)
+      end extension
       private def effectivePatterns(patterns: List[Tree]): List[Tree] =
         patterns match
           case patterns0 :+ dotc.ast.Trees.SeqLiteral(elems, _) => patterns0 ::: elems
diff --git a/compiler/src/scala/quoted/runtime/impl/printers/SourceCode.scala b/compiler/src/scala/quoted/runtime/impl/printers/SourceCode.scala
index 62fa24d908f1..bc911552a614 100644
--- a/compiler/src/scala/quoted/runtime/impl/printers/SourceCode.scala
+++ b/compiler/src/scala/quoted/runtime/impl/printers/SourceCode.scala
@@ -530,6 +530,9 @@ object SourceCode {
       case Closure(meth, _) =>
         printTree(meth)
 
+      case _:Unapply | _:Alternatives | _:Bind =>
+        printPattern(tree)
+
       case _ =>
         throw new MatchError(tree.show(using Printer.TreeStructure))
 
diff --git a/library/src/scala/quoted/Quotes.scala b/library/src/scala/quoted/Quotes.scala
index 96424a176b35..7c4733255559 100644
--- a/library/src/scala/quoted/Quotes.scala
+++ b/library/src/scala/quoted/Quotes.scala
@@ -4359,7 +4359,7 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
           case New(tpt) =>
             New.copy(tree)(transformTypeTree(tpt)(owner))
           case Typed(expr, tpt) =>
-            Typed.copy(tree)(transformTerm(expr)(owner), transformTypeTree(tpt)(owner))
+            Typed.copy(tree)(/*FIXME #12222: transformTerm(expr)(owner)*/transformTree(expr)(owner).asInstanceOf[Term], transformTypeTree(tpt)(owner))
           case tree: NamedArg =>
             NamedArg.copy(tree)(tree.name, transformTerm(tree.value)(owner))
           case Assign(lhs, rhs) =>
diff --git a/tests/run-staging/i5161.check b/tests/run-staging/i5161.check
index 27c72498d7f1..a178c827d633 100644
--- a/tests/run-staging/i5161.check
+++ b/tests/run-staging/i5161.check
@@ -1,6 +1,6 @@
 run : Some(2)
 show : scala.Tuple2.apply[scala.Option[scala.Int], scala.Option[scala.Int]](scala.Some.apply[scala.Int](1), scala.Some.apply[scala.Int](1)) match {
-  case scala.Tuple2(scala.Some(x), scala.Some(y)) =>
+  case scala.Tuple2((scala.Some(x): scala.Some[scala.Int]), (scala.Some(y): scala.Some[scala.Int])) =>
     scala.Some.apply[scala.Int](x.+(y))
   case _ =>
     scala.None