From 756e46bfe3025e1f0f441fb779c37598555f08bc Mon Sep 17 00:00:00 2001
From: Ron Buckton <ron.buckton@microsoft.com>
Date: Mon, 11 Jun 2018 17:59:32 -0700
Subject: [PATCH] Reuse resolvedProjectReferences

---
 src/compiler/program.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 856f9580f0e..8a741cc93d0 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -616,7 +616,7 @@ namespace ts {
         const filesByNameIgnoreCase = host.useCaseSensitiveFileNames() ? createMap<SourceFile>() : undefined;
 
         // A parallel array to projectReferences storing the results of reading in the referenced tsconfig files
-        const resolvedProjectReferences: (ResolvedProjectReference | undefined)[] | undefined = projectReferences ? [] : undefined;
+        let resolvedProjectReferences: (ResolvedProjectReference | undefined)[] | undefined = projectReferences ? [] : undefined;
         const projectReferenceRedirects: Map<string> = createMap();
 
         const shouldCreateNewSourceFile = shouldProgramCreateNewSourceFiles(oldProgram, options);
@@ -1190,6 +1190,7 @@ namespace ts {
                 fileProcessingDiagnostics.reattachFileDiagnostics(modifiedFile.newFile);
             }
             resolvedTypeReferenceDirectives = oldProgram.getResolvedTypeReferenceDirectives();
+            resolvedProjectReferences = oldProgram.getProjectReferences();
 
             sourceFileToPackageName = oldProgram.sourceFileToPackageName;
             redirectTargetsSet = oldProgram.redirectTargetsSet;