From 54b7aa5ff6cf4b76978e985661cc64c649d07144 Mon Sep 17 00:00:00 2001
From: noti0na1 <noti0na1@users.noreply.github.com>
Date: Thu, 24 Feb 2022 16:53:30 -0500
Subject: [PATCH] Add a todo comment

---
 compiler/src/dotty/tools/dotc/core/Contexts.scala       | 2 +-
 compiler/src/dotty/tools/dotc/core/GadtConstraint.scala | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/compiler/src/dotty/tools/dotc/core/Contexts.scala b/compiler/src/dotty/tools/dotc/core/Contexts.scala
index 49bb763334de..04610ce8e478 100644
--- a/compiler/src/dotty/tools/dotc/core/Contexts.scala
+++ b/compiler/src/dotty/tools/dotc/core/Contexts.scala
@@ -839,7 +839,7 @@ object Contexts {
     gadt = EmptyGadtConstraint
   }
 
-  @sharable object NoContext extends Context(null.asInstanceOf) {
+  @sharable object NoContext extends Context((null: ContextBase | Null).uncheckedNN) {
     source = NoSource
     override val implicits: ContextualImplicits = new ContextualImplicits(Nil, null, false)(this)
   }
diff --git a/compiler/src/dotty/tools/dotc/core/GadtConstraint.scala b/compiler/src/dotty/tools/dotc/core/GadtConstraint.scala
index a443db54c4a8..553401f92ca6 100644
--- a/compiler/src/dotty/tools/dotc/core/GadtConstraint.scala
+++ b/compiler/src/dotty/tools/dotc/core/GadtConstraint.scala
@@ -107,6 +107,7 @@ final class ProperGadtConstraint private(
               params.indexOf(tp.symbol) match {
                 case -1 =>
                   mapping(tp.symbol) match {
+                    // TODO: Improve flow typing so that ascription becomes redundant, see #11967
                     case tv: TypeVar => tv.origin
                     case null => tp
                   }