From 11583b81538fdf83f8ccdcdc5781776b4d6bb447 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Thu, 5 Mar 2020 10:35:26 +0100
Subject: [PATCH] Refine atoms computation on intersection types

---
 compiler/src/dotty/tools/dotc/core/Atoms.scala | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/compiler/src/dotty/tools/dotc/core/Atoms.scala b/compiler/src/dotty/tools/dotc/core/Atoms.scala
index 951ed1bc2205..bcaaf6794107 100644
--- a/compiler/src/dotty/tools/dotc/core/Atoms.scala
+++ b/compiler/src/dotty/tools/dotc/core/Atoms.scala
@@ -20,8 +20,11 @@ enum Atoms:
     case Range(lo1, hi1) =>
       that match
         case Range(lo2, hi2) => Range(lo1 & lo2, hi1 & hi2)
-        case Unknown => this
-    case Unknown => that
+        case Unknown => Range(Set.empty, hi1)
+    case Unknown =>
+      that match
+        case Range(lo2, hi2) => Range(Set.empty, hi2)
+        case Unknown => Unknown
 
   def | (that: Atoms): Atoms = this match
     case Range(lo1, hi1) =>