From 49c0cca75b02a44142a2fb06baa244b30a27d638 Mon Sep 17 00:00:00 2001
From: Yuito Murase <yuito@acupof.coffee>
Date: Mon, 7 Aug 2023 14:20:02 +0900
Subject: [PATCH] Move bound check from Typer to QuotePatterns

---
 .../tools/dotc/quoted/QuotePatterns.scala     |  7 ++++++-
 .../tools/dotc/typer/QuotesAndSplices.scala   | 21 +++++++------------
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/compiler/src/dotty/tools/dotc/quoted/QuotePatterns.scala b/compiler/src/dotty/tools/dotc/quoted/QuotePatterns.scala
index 66085a21e93c..9c6c6f7f3839 100644
--- a/compiler/src/dotty/tools/dotc/quoted/QuotePatterns.scala
+++ b/compiler/src/dotty/tools/dotc/quoted/QuotePatterns.scala
@@ -29,7 +29,12 @@ object QuotePatterns:
   def checkPattern(quotePattern: QuotePattern)(using Context): Unit =
     val typevars = new tpd.TreeAccumulator[Set[Symbol]] {
       override def apply(typevars: Set[Symbol], tree: tpd.Tree)(using Context): Set[Symbol] = tree match {
-        case _: SplicePattern => typevars
+        case tree: SplicePattern =>
+          for typearg <- tree.typeargs
+          do
+            if !(typearg.tpe.bounds.lo == defn.AnyType && typearg.tpe.bounds.hi == defn.NothingType) then
+              report.error(em"Type arguments of hoas patterns should not have bounds")
+          typevars
         case tree @ DefDef(_, paramss, _, _) =>
           val newTypevars = paramss.flatMap{ params => params match
             case TypeDefs(tdefs) => tdefs.map(_.symbol)
diff --git a/compiler/src/dotty/tools/dotc/typer/QuotesAndSplices.scala b/compiler/src/dotty/tools/dotc/typer/QuotesAndSplices.scala
index e4582434f47d..a4b0d25c7c8a 100644
--- a/compiler/src/dotty/tools/dotc/typer/QuotesAndSplices.scala
+++ b/compiler/src/dotty/tools/dotc/typer/QuotesAndSplices.scala
@@ -110,6 +110,13 @@ trait QuotesAndSplices {
   def typedSplicePattern(tree: untpd.SplicePattern, pt: Type)(using Context): Tree = {
     record("typedSplicePattern")
     if isFullyDefined(pt, ForceDegree.flipBottom) then
+      val typedTypeargs = tree.typeargs.map {
+        case typearg: untpd.Ident =>
+          typedType(typearg)
+        case arg =>
+          report.error("Open pattern expected an identifier", arg.srcPos)
+          EmptyTree
+      }
       val typedArgs = withMode(Mode.InQuotePatternHoasArgs) {
         tree.args.map {
           case arg: untpd.Ident =>
@@ -119,20 +126,6 @@ trait QuotesAndSplices {
             EmptyTree
         }
       }
-      val typedTypeargs = tree.typeargs.map {
-        case typearg: untpd.Ident =>
-          val typedTypearg = typedType(typearg)
-          /* TODO-18271: Allow type bounds?
-           * (NOTE: Needs non-trivial extension to type system)
-           */
-          val bounds = ctx.gadt.fullBounds(typedTypearg.symbol)
-          if bounds != null && bounds != TypeBounds.empty then
-            report.error("Type arguments to Open pattern are expected to have no bounds", typearg.srcPos)
-          typedTypearg
-        case arg =>
-          report.error("Open pattern expected an identifier", arg.srcPos)
-          EmptyTree
-      }
       for arg <- typedArgs if arg.symbol.is(Mutable) do // TODO support these patterns. Possibly using scala.quoted.util.Var
         report.error("References to `var`s cannot be used in higher-order pattern", arg.srcPos)
       val argTypes = typedArgs.map(_.tpe.widenTermRefExpr)