From 5079ffe722b915b635cbd95b3238b65b5df3df34 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Wed, 17 Mar 2021 12:25:44 +0100
Subject: [PATCH] Add missing case to couldInstantiateTypeVar

Fixes #11778
---
 compiler/src/dotty/tools/dotc/typer/Inferencing.scala | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/compiler/src/dotty/tools/dotc/typer/Inferencing.scala b/compiler/src/dotty/tools/dotc/typer/Inferencing.scala
index 18a181c6667a..59ee126f382d 100644
--- a/compiler/src/dotty/tools/dotc/typer/Inferencing.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Inferencing.scala
@@ -102,7 +102,7 @@ object Inferencing {
     case AppliedType(tycon, args) =>
       // The argument in `args` that may potentially appear directly as result
       // and thereby influence the members of this type
-      def argsInResult: List[Type] = tycon match
+      def argsInResult: List[Type] = tycon.stripTypeVar match
         case tycon: TypeRef =>
           tycon.info match
             case MatchAlias(_) => args
@@ -114,6 +114,7 @@ object Inferencing {
                   }.toList
                 case _ => Nil
             case _ => Nil
+        case _ => Nil
       couldInstantiateTypeVar(tycon)
       || argsInResult.exists(couldInstantiateTypeVar)
     case RefinedType(parent, _, _) =>