From 1a6022d6dd43564a496b8b63a4818832513d5857 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wwigham@gmail.com>
Date: Wed, 25 Oct 2017 17:04:41 -0700
Subject: [PATCH] Stop using expensive directoryExists in unit/rwc tests where
 it does not matter (#19486)

---
 src/harness/harness.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index 9622a6df332..b867ca77628 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -1196,6 +1196,9 @@ namespace Harness {
                 traceResults = [];
                 compilerHost.trace = text => traceResults.push(text);
             }
+            else {
+                compilerHost.directoryExists = () => true; // This only visibly affects resolution traces, so to save time we always return true where possible
+            }
             const program = ts.createProgram(programFileNames, options, compilerHost);
 
             const emitResult = program.emit();