From 97befd0520f3d60e6ca040faef75ab26ab7a41a1 Mon Sep 17 00:00:00 2001
From: "sebastian.sellmair" <sebastian.sellmair@jetbrains.com>
Date: Wed, 15 Sep 2021 14:21:50 +0200
Subject: [PATCH] [Commonizer] Consider negative type distances 'worse'

^KT-48288
---
 .../commonizer/core/ClassOrTypeAliasTypeCommonizer.kt  | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/native/commonizer/src/org/jetbrains/kotlin/commonizer/core/ClassOrTypeAliasTypeCommonizer.kt b/native/commonizer/src/org/jetbrains/kotlin/commonizer/core/ClassOrTypeAliasTypeCommonizer.kt
index a485402459c..f9563f81a71 100644
--- a/native/commonizer/src/org/jetbrains/kotlin/commonizer/core/ClassOrTypeAliasTypeCommonizer.kt
+++ b/native/commonizer/src/org/jetbrains/kotlin/commonizer/core/ClassOrTypeAliasTypeCommonizer.kt
@@ -232,8 +232,14 @@ private fun resolveTypeSubstitutionCandidates(
         if (typeDistances.any { it.isNotReachable }) return@mapCandidateId null
         TypeSubstitutionCandidate(
             id = candidateId,
-            // TODO NOW: Any negative should outperform any positive substitution!, so negative will be chosen here as 'worst'
-            typeDistance = checkNotNull(typeDistances.maxByOrNull { distance -> distance.absoluteValue })
+            typeDistance = checkNotNull(typeDistances.worstOrNull())
         )
     }
 }
+
+private fun List<CirTypeDistance>.worstOrNull(): CirTypeDistance? {
+    if (this.isEmpty()) return null
+    // Negative Type Distances are considered 'worse'
+    filter { it.isNegative }.minOrNull()?.let { return it }
+    return maxOrNull()
+}
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