From ab0d7a7adf016562dc9f1872f4b4cc2d55659d71 Mon Sep 17 00:00:00 2001
From: Don Syme <dsyme@users.noreply.github.com>
Date: Wed, 8 Feb 2017 17:55:31 +0000
Subject: [PATCH] don't keep tcEnvAtEnd for background states unless
 keepAllBackgroundResolutions=true (#2388)

---
 src/fsharp/vs/IncrementalBuild.fs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/fsharp/vs/IncrementalBuild.fs b/src/fsharp/vs/IncrementalBuild.fs
index edb85f92e8..04d6bb363d 100755
--- a/src/fsharp/vs/IncrementalBuild.fs
+++ b/src/fsharp/vs/IncrementalBuild.fs
@@ -1427,8 +1427,8 @@ type IncrementalBuilder(frameworkTcImportsCache: FrameworkImportsCache, tcConfig
                 errorLogger.Warning(e)
                 frameworkTcImports           
 
-        let tcEnvAtEndOfFile = GetInitialTcEnv (assemblyName, rangeStartup, tcConfig, tcImports, tcGlobals)
-        let tcState = GetInitialTcState (rangeStartup, assemblyName, tcConfig, tcGlobals, tcImports, niceNameGen, tcEnvAtEndOfFile)
+        let tcInitial = GetInitialTcEnv (assemblyName, rangeStartup, tcConfig, tcImports, tcGlobals)
+        let tcState = GetInitialTcState (rangeStartup, assemblyName, tcConfig, tcGlobals, tcImports, niceNameGen, tcInitial)
         let loadClosureErrors = 
            [ match loadClosureOpt with 
              | None -> ()
@@ -1442,7 +1442,7 @@ type IncrementalBuilder(frameworkTcImportsCache: FrameworkImportsCache, tcConfig
               tcImports=tcImports
               tcState=tcState
               tcConfig=tcConfig
-              tcEnvAtEndOfFile=tcEnvAtEndOfFile
+              tcEnvAtEndOfFile=tcInitial
               tcResolutions=[]
               tcSymbolUses=[]
               topAttribs=None
@@ -1479,6 +1479,7 @@ type IncrementalBuilder(frameworkTcImportsCache: FrameworkImportsCache, tcConfig
                     /// Only keep the typed interface files when doing a "full" build for fsc.exe, otherwise just throw them away
                     let typedImplFiles = if keepAssemblyContents then typedImplFiles else []
                     let tcResolutions = if keepAllBackgroundResolutions then sink.GetResolutions() else TcResolutions.Empty
+                    let tcEnvAtEndOfFile = (if keepAllBackgroundResolutions then tcEnvAtEndOfFile else tcState.TcEnvFromImpls)
                     let tcSymbolUses = sink.GetSymbolUses()  
                     fileChecked.Trigger (filename)
                     return {tcAcc with tcState=tcState