From 5a567ad56dac117340a77616504bb666adf3f5e0 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sat, 27 Apr 2019 09:56:01 -0700
Subject: [PATCH] Properly instantiate true type when extends type is any or
 unknown

---
 src/compiler/checker.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 8ee0a4c051996..1431f877d8e32 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -10383,7 +10383,7 @@ namespace ts {
             // We attempt to resolve the conditional type only when the check and extends types are non-generic
             if (!checkTypeInstantiable && !maybeTypeOfKind(inferredExtendsType, TypeFlags.Instantiable | TypeFlags.GenericMappedType)) {
                 if (inferredExtendsType.flags & TypeFlags.AnyOrUnknown) {
-                    return trueType;
+                    return instantiateType(root.trueType, combinedMapper || mapper);
                 }
                 // Return union of trueType and falseType for 'any' since it matches anything
                 if (checkType.flags & TypeFlags.Any) {