Merge remote-tracking branch 'upstream/dev16.0' into merges/dev16.0-to-master

2019-04-02 13:35:19 -07:00 · 2019-04-02 13:35:19 -07:00 · bd24505312
--- a/.vsts-pr.yaml
+++ b/.vsts-pr.yaml
@ -90,7 +90,7 @@ jobs:

 - job: Windows
  pool:
-    vmImage: vs2017-win2016
+    vmImage: windows-2019
  timeoutInMinutes: 120
  strategy:
    maxParallel: 4
@ -128,7 +128,7 @@ jobs:

 - job: Windows_FCS
  pool:
-    vmImage: vs2017-win2016
+    vmImage: windows-2019
  timeoutInMinutes: 120
  steps:
  - script: fcs\build.cmd TestAndNuget
--- a/DEVGUIDE.md
+++ b/DEVGUIDE.md
@ -66,7 +66,7 @@ Running tests:

 To build and test Visual F# IDE Tools, install these requirements:

- Download [Visual Studio 2017](https://www.visualstudio.com/downloads/)
+- Download [Visual Studio 2019](https://www.visualstudio.com/downloads/)
 - Launch the Visual Studio Installer
  - Under the **"Windows"** workload, select **".NET desktop development"**
    - Select the optional component **"F# desktop language support"**
@ -78,11 +78,11 @@ Steps to build:

    Build.cmd                             -- build all F# components under the default configuration (Debug)
    Build.cmd -configuration Release      -- build all F# components as Release
-    Build.cmd -testDesktop                -- build and test all net46 tests
+    Build.cmd -testDesktop                -- build and test all net472 tests

 All test options:

-    -testDesktop                          -- test all net46 target frameworks
+    -testDesktop                          -- test all net472 target frameworks
    -testCoreClr                          -- test all netstandard and netcoreapp target frameworks
    -testFSharpQA                         -- test all F# Cambridge tests
    -testVs                               -- test all VS integration points
@ -95,18 +95,18 @@ Note on Debug vs Release: ``Release`` Configuration has a degraded debugging exp

 Note ([#2351](https://github.com/Microsoft/visualfsharp/issues/2351)): if you face this error:

-> error VSSDK1077: Unable to locate the extensions directory. "ExternalSettingsManager::GetScopePaths failed to initialize PkgDefManager for C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\devenv.exe".
+> error VSSDK1077: Unable to locate the extensions directory. "ExternalSettingsManager::GetScopePaths failed to initialize PkgDefManager for C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\IDE\devenv.exe".

 Or hard crash on launch ("Unknown Error"), delete these folders:

- `%localappdata%\Microsoft\VisualStudio\15.0_(some number here)RoslynDev`
- `%localappdata%\Microsoft\VisualStudio\15.0_(some number here)`
+- `%localappdata%\Microsoft\VisualStudio\16.0_(some number here)RoslynDev`
+- `%localappdata%\Microsoft\VisualStudio\16.0_(some number here)`

 #### [Optional] Install the Visual F# IDE Tools  (Windows Only)

 The new builds of the Visual F# IDE Tools can no longer be installed into Visual Studio 2015.

-You can install Visual Studio 2017 from https://www.visualstudio.com/downloads/.
+You can install Visual Studio 2019 from https://www.visualstudio.com/downloads/.

 **Note:** This step will install a VSIX extension into Visual Studio "Next" that changes the Visual F# IDE Tools 
 components installed in that VS installation.  You can revert this step by disabling or uninstalling the addin.
@ -135,15 +135,15 @@ Because this uses the "RoslynDev" hive you can simultaneously test changes to an

 #### [Optional] Rapid deployment of incremental changes to Visual F# IDE Tools components

-For the brave, you can rapidly deploy incrementally updated versions of Visual F# IDE Tool components such as ``FSHarp.Editor.dll`` by copying them directly into the extension directory in your user AppData folder:
+For the brave, you can rapidly deploy incrementally updated versions of Visual F# IDE Tool components such as ``FSharp.Editor.dll`` by copying them directly into the extension directory in your user AppData folder:

-    xcopy /y debug\net40\bin\FSharp.* "%USERPROFILE%\AppData\Local\Microsoft\VisualStudio\15.0_7c5620b7FSharpDev\Extensions\Microsoft.VisualFSharpTools\Visual F# Tools\15.4.1.9055"
+    xcopy /y debug\net40\bin\FSharp.* "%USERPROFILE%\AppData\Local\Microsoft\VisualStudio\16.0_7c5620b7FSharpDev\Extensions\Microsoft.VisualFSharpTools\Visual F# Tools\16.4.1.9055"

 This gives a much tighter inner development loop than uninstalling/reinstalling the VSIX, as you do not have to restart VIsual Studio. Caveat emptor.

 #### [Optional] Clobber the F# SDK on the machine

-**Note:** The step below will try to clobber the machine-wide installed F# SDK on your machine. This replaces the ``fsc.exe`` used by the standard install location or ``Microsoft.FSharp.Targets``.  **Repairing Visual Studio 15 is currently the only way to revert this step.**
+**Note:** The step below will try to clobber the machine-wide installed F# SDK on your machine. This replaces the ``fsc.exe`` used by the standard install location or ``Microsoft.FSharp.Targets``.  **Repairing Visual Studio 16 is currently the only way to revert this step.**

 For **Debug**:

@ -184,7 +184,7 @@ If you change error messages you may need to update FSComp.fs in `src\buildfroms
 To do this, build the non-buildfromsource version of FSharp.Compiler.Private (src\fsharp\FSharp.Compiler.Private) then check its obj\ directory for `FSComp.fs` and manually copy that into the buildfromsource directory.

    .\build net40
-    copy /y artifacts\obj\FSharp.Compiler.Private\Release\net46\FSComp.* src\buildfromsource\FSharp.Compiler.Private\
+    copy /y artifacts\obj\FSharp.Compiler.Private\Release\net472\FSComp.* src\buildfromsource\FSharp.Compiler.Private\

 If your changes involve modifying the list of language keywords in any way, (e.g. when implementing a new keyword), the XLF localization files need to be synced with the corresponding resx files. This can be done automatically by running

--- a/FSharpBuild.Directory.Build.targets
+++ b/FSharpBuild.Directory.Build.targets
@ -4,16 +4,6 @@
  <Import Project="eng\targets\NGenBinaries.targets" />
  <Import Project="FSharp.Profiles.props" />

-  <PropertyGroup Condition="'$(UseAssetTargetFallback)' == 'true'">
-    <!--
-    HACK: Necessary because the `netstandard1.6` version of FSharp.Compiler.Private requires a package that isn't
-    necessary for `net46`, but the package has a requirement on `net462`.  The reference is excluded from the build
-    during `net46`, but for purposes of restore needs to be present.
-    -->
-    <AssetTargetFallback>$(AssetTargetFallback);net462</AssetTargetFallback>
-    <NoWarn>$(NoWarn);NU1605;NU1701</NoWarn>
-  </PropertyGroup>
-
  <PropertyGroup>
    <CompileDependsOn>$(CompileDependsOn);CopyAndSubstituteTextFiles</CompileDependsOn>
  </PropertyGroup>
--- a/FSharpTests.Directory.Build.props
+++ b/FSharpTests.Directory.Build.props
@ -7,11 +7,11 @@
  <PropertyGroup Condition="'$(FSharpTestCompilerVersion)' == 'net40'">
    <DisableAutoSetFscCompilerPath>true</DisableAutoSetFscCompilerPath>

-    <FscToolPath>$(MSBuildThisFileDirectory)artifacts\bin\fsc\$(Configuration)\net46</FscToolPath>
+    <FscToolPath>$(MSBuildThisFileDirectory)artifacts\bin\fsc\$(Configuration)\net472</FscToolPath>
    <FscToolExe>fsc.exe</FscToolExe>
    <DotnetFscCompilerPath></DotnetFscCompilerPath>

-    <FsiToolPath>$(MSBuildThisFileDirectory)artifacts\bin\fsi\$(Configuration)\net46</FsiToolPath>
+    <FsiToolPath>$(MSBuildThisFileDirectory)artifacts\bin\fsi\$(Configuration)\net472</FsiToolPath>
    <FsiToolExe>fsi.exe</FsiToolExe>
    <DotnetFsiCompilerPath></DotnetFsiCompilerPath>
  </PropertyGroup>
@ -32,7 +32,7 @@

  <!-- SDK targets override -->
  <PropertyGroup>
-    <_FSharpBuildTargetFramework Condition="'$(FSharpTestCompilerVersion)' == 'net40'">net46</_FSharpBuildTargetFramework>
+    <_FSharpBuildTargetFramework Condition="'$(FSharpTestCompilerVersion)' == 'net40'">net472</_FSharpBuildTargetFramework>
    <_FSharpBuildTargetFramework Condition="'$(FSharpTestCompilerVersion)' == 'coreclr'">netstandard2.0</_FSharpBuildTargetFramework>
    <_FSharpBuildBinPath>$(MSBuildThisFileDirectory)artifacts\bin\FSharp.Build\$(Configuration)\$(_FSharpBuildTargetFramework)</_FSharpBuildBinPath>

--- a/RoslynPackageVersion.txt
+++ b/RoslynPackageVersion.txt
@ -1 +1 @@
-2.9.0-beta8-63208-01
+3.0.0-beta4-19170-01
--- a/VisualFSharp.sln
+++ b/VisualFSharp.sln
@ -1,7 +1,7 @@

 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 15
-VisualStudioVersion = 15.0.28010.2036
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.28729.10
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Tests", "Tests", "{CFE3259A-2D30-4EB0-80D5-E8B5F3D01449}"
 EndProject
@ -48,7 +48,7 @@ Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "FSharp.Editor", "vsintegrat
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ProjectSystem.Base", "vsintegration\src\FSharp.ProjectSystem.Base\Project\ProjectSystem.Base.csproj", "{B700E38B-F8C0-4E49-B5EC-DB7B7AC0C4E7}"
 EndProject
-Project("{F184B08F-C81C-45F6-A57F-5ABD9991F28F}") = "FSharp.PropertiesPages", "vsintegration\src\FSharp.ProjectSystem.PropertyPages\FSharp.PropertiesPages.vbproj", "{FCFB214C-462E-42B3-91CA-FC557EFEE74F}"
+Project("{778DAE3C-4631-46EA-AA77-85C1314464D9}") = "FSharp.PropertiesPages", "vsintegration\src\FSharp.ProjectSystem.PropertyPages\FSharp.PropertiesPages.vbproj", "{FCFB214C-462E-42B3-91CA-FC557EFEE74F}"
 EndProject
 Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "ProjectSystem", "vsintegration\src\FSharp.ProjectSystem.FSharp\ProjectSystem.fsproj", "{6196B0F8-CAEA-4CF1-AF82-1B520F77FE44}"
 EndProject
@ -288,10 +288,10 @@ Global
 		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Debug|x86.ActiveCfg = Debug|Any CPU
 		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Debug|x86.Build.0 = Debug|Any CPU
-		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Proto|Any CPU.ActiveCfg = Proto|Any CPU
-		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Proto|Any CPU.Build.0 = Proto|Any CPU
-		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Proto|x86.ActiveCfg = Proto|Any CPU
-		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Proto|x86.Build.0 = Proto|Any CPU
+		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Proto|Any CPU.ActiveCfg = Release|Any CPU
+		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Proto|Any CPU.Build.0 = Release|Any CPU
+		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Proto|x86.ActiveCfg = Release|Any CPU
+		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Proto|x86.Build.0 = Release|Any CPU
 		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Release|Any CPU.Build.0 = Release|Any CPU
 		{FCFB214C-462E-42B3-91CA-FC557EFEE74F}.Release|x86.ActiveCfg = Release|Any CPU
--- a/benchmarks/Benchmarks.sln
+++ b/benchmarks/Benchmarks.sln
@ -1,32 +1,39 @@

 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 15
-VisualStudioVersion = 15.0.28307.136
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.28407.52
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "CompilerServiceBenchmarks", "CompilerServiceBenchmarks\CompilerServiceBenchmarks.fsproj", "{9A3C565C-B514-4AE0-8B01-CA80E8453EB0}"
+Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "CompilerServiceBenchmarks", "CompilerServiceBenchmarks\CompilerServiceBenchmarks.fsproj", "{9A3C565C-B514-4AE0-8B01-CA80E8453EB0}"
 EndProject
-Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "FSharp.Core", "..\src\fsharp\FSharp.Core\FSharp.Core.fsproj", "{BB9EAE76-194A-49D8-9618-586CBE7031D9}"
+Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "FSharp.Core", "..\src\fsharp\FSharp.Core\FSharp.Core.fsproj", "{DED3BBD7-53F4-428A-8C9F-27968E768605}"
 EndProject
-Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "FSharp.Compiler.Private", "..\src\fsharp\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj", "{F57B02B1-CF26-4D93-9211-8CEB4F1572F0}"
+Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "FSharp.Compiler.Private", "..\src\fsharp\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj", "{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
+		Proto|Any CPU = Proto|Any CPU
 		Release|Any CPU = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
 		{9A3C565C-B514-4AE0-8B01-CA80E8453EB0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{9A3C565C-B514-4AE0-8B01-CA80E8453EB0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9A3C565C-B514-4AE0-8B01-CA80E8453EB0}.Proto|Any CPU.ActiveCfg = Release|Any CPU
+		{9A3C565C-B514-4AE0-8B01-CA80E8453EB0}.Proto|Any CPU.Build.0 = Release|Any CPU
 		{9A3C565C-B514-4AE0-8B01-CA80E8453EB0}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{9A3C565C-B514-4AE0-8B01-CA80E8453EB0}.Release|Any CPU.Build.0 = Release|Any CPU
-		{BB9EAE76-194A-49D8-9618-586CBE7031D9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{BB9EAE76-194A-49D8-9618-586CBE7031D9}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{BB9EAE76-194A-49D8-9618-586CBE7031D9}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{BB9EAE76-194A-49D8-9618-586CBE7031D9}.Release|Any CPU.Build.0 = Release|Any CPU
-		{F57B02B1-CF26-4D93-9211-8CEB4F1572F0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{F57B02B1-CF26-4D93-9211-8CEB4F1572F0}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{F57B02B1-CF26-4D93-9211-8CEB4F1572F0}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{F57B02B1-CF26-4D93-9211-8CEB4F1572F0}.Release|Any CPU.Build.0 = Release|Any CPU
+		{DED3BBD7-53F4-428A-8C9F-27968E768605}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{DED3BBD7-53F4-428A-8C9F-27968E768605}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{DED3BBD7-53F4-428A-8C9F-27968E768605}.Proto|Any CPU.ActiveCfg = Debug|Any CPU
+		{DED3BBD7-53F4-428A-8C9F-27968E768605}.Proto|Any CPU.Build.0 = Debug|Any CPU
+		{DED3BBD7-53F4-428A-8C9F-27968E768605}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{DED3BBD7-53F4-428A-8C9F-27968E768605}.Release|Any CPU.Build.0 = Release|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Proto|Any CPU.ActiveCfg = Debug|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Proto|Any CPU.Build.0 = Debug|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
--- a/benchmarks/CompilerServiceBenchmarks/CompilerServiceBenchmarks.fsproj
+++ b/benchmarks/CompilerServiceBenchmarks/CompilerServiceBenchmarks.fsproj
@ -1,8 +1,19 @@
 <Project Sdk="Microsoft.NET.Sdk">

+  <PropertyGroup>
+    <FSharpSourcesRoot>$(MSBuildProjectDirectory)\..\..\src</FSharpSourcesRoot>
+  </PropertyGroup>
+
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net472</TargetFramework>
+    <DisableImplicitFSharpCoreReference>true</DisableImplicitFSharpCoreReference>
+    <DisableImplicitSystemValueTupleReference>true</DisableImplicitSystemValueTupleReference>
+    <DefaultValueTuplePackageVersion>$(SystemValueTuplePackageVersion)</DefaultValueTuplePackageVersion>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
+    <PlatformTarget>AnyCPU</PlatformTarget>
  </PropertyGroup>

  <ItemGroup>
@ -11,11 +22,12 @@

  <ItemGroup>
    <PackageReference Include="BenchmarkDotNet" Version="0.11.3" />
+    <PackageReference Include="Microsoft.CodeAnalysis.EditorFeatures.Text" Version="2.9.0" />
  </ItemGroup>

  <ItemGroup>
-    <ProjectReference Include="..\..\src\fsharp\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj" />
-    <ProjectReference Include="..\..\src\fsharp\FSharp.Core\FSharp.Core.fsproj" />
+    <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj" />
+    <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Core\FSharp.Core.fsproj" />
  </ItemGroup>

 </Project>
--- a/benchmarks/CompilerServiceBenchmarks/Program.fs
+++ b/benchmarks/CompilerServiceBenchmarks/Program.fs
@ -1,13 +1,87 @@
 open System
 open System.IO
-open BenchmarkDotNet.Attributes
-open BenchmarkDotNet.Running
+open System.Text
 open FSharp.Compiler.ErrorLogger
 open FSharp.Compiler.SourceCodeServices
-open System.Text
+open FSharp.Compiler.Text
+open FSharp.Compiler.AbstractIL
+open FSharp.Compiler.AbstractIL.IL
+open FSharp.Compiler.AbstractIL.ILBinaryReader
+open CodeAnalysis.Text
+open BenchmarkDotNet.Attributes
+open BenchmarkDotNet.Running

-[<ClrJob(baseline = true)>]
-type CompilerServiceParsing() =
+module private SourceText =
+
+    open System.Runtime.CompilerServices
+
+    let weakTable = ConditionalWeakTable<SourceText, ISourceText>()
+
+    let create (sourceText: SourceText) =
+
+        let sourceText =
+            { new ISourceText with
+            
+                member __.Item with get index = sourceText.[index]
+
+                member __.GetLineString(lineIndex) =
+                    sourceText.Lines.[lineIndex].ToString()
+
+                member __.GetLineCount() =
+                    sourceText.Lines.Count
+
+                member __.GetLastCharacterPosition() =
+                    if sourceText.Lines.Count > 0 then
+                        (sourceText.Lines.Count, sourceText.Lines.[sourceText.Lines.Count - 1].Span.Length)
+                    else
+                        (0, 0)
+
+                member __.GetSubTextString(start, length) =
+                    sourceText.GetSubText(TextSpan(start, length)).ToString()
+
+                member __.SubTextEquals(target, startIndex) =
+                    if startIndex < 0 || startIndex >= sourceText.Length then
+                        raise (ArgumentOutOfRangeException("startIndex"))
+
+                    if String.IsNullOrEmpty(target) then
+                        raise (ArgumentException("Target is null or empty.", "target"))
+
+                    let lastIndex = startIndex + target.Length
+                    if lastIndex <= startIndex || lastIndex >= sourceText.Length then
+                        raise (ArgumentException("Target is too big.", "target"))
+
+                    let mutable finished = false
+                    let mutable didEqual = true
+                    let mutable i = 0
+                    while not finished && i < target.Length do
+                        if target.[i] <> sourceText.[startIndex + i] then
+                            didEqual <- false
+                            finished <- true // bail out early                        
+                        else
+                            i <- i + 1
+
+                    didEqual
+
+                member __.ContentEquals(sourceText) =
+                    match sourceText with
+                    | :? SourceText as sourceText -> sourceText.ContentEquals(sourceText)
+                    | _ -> false
+
+                member __.Length = sourceText.Length
+
+                member __.CopyTo(sourceIndex, destination, destinationIndex, count) =
+                    sourceText.CopyTo(sourceIndex, destination, destinationIndex, count)
+            }
+
+        sourceText
+
+type SourceText with
+
+    member this.ToFSharpSourceText() =
+        SourceText.weakTable.GetValue(this, Runtime.CompilerServices.ConditionalWeakTable<_,_>.CreateValueCallback(SourceText.create))
+
+[<MemoryDiagnoser>]
+type CompilerService() =

    let mutable checkerOpt = None

@ -24,6 +98,17 @@ type CompilerServiceParsing() =
            IsExe = false
        }

+    let mutable assembliesOpt = None
+
+    let readerOptions =
+        {
+            pdbDirPath = None
+            ilGlobals = mkILGlobals ILScopeRef.Local
+            reduceMemoryUsage = ReduceMemoryFlag.No
+            metadataOnly = MetadataOnlyFlag.Yes
+            tryGetMetadataSnapshot = fun _ -> None
+        }
+
    [<GlobalSetup>]
    member __.Setup() =
        match checkerOpt with
@ -32,18 +117,25 @@ type CompilerServiceParsing() =

        match sourceOpt with
        | None ->
-            let source = File.ReadAllText("""..\..\..\..\..\src\fsharp\TypeChecker.fs""")
-            sourceOpt <- Some(source)
+            sourceOpt <- Some <| SourceText.From(File.OpenRead("""..\..\..\..\..\src\fsharp\TypeChecker.fs"""), Encoding.Default, SourceHashAlgorithm.Sha1, true)
+        | _ -> ()
+
+        match assembliesOpt with
+        | None -> 
+            assembliesOpt <- 
+                System.AppDomain.CurrentDomain.GetAssemblies()
+                |> Array.map (fun x -> (x.Location))
+                |> Some
        | _ -> ()
    
-    [<IterationSetup>]
+    [<IterationSetup(Target = "Parsing")>]
    member __.ParsingSetup() =
        match checkerOpt with
        | None -> failwith "no checker"
        | Some(checker) ->
            checker.InvalidateAll()
            checker.ClearLanguageServiceRootCachesAndCollectAndFinalizeAllTransients()
-            checker.ParseFile("dummy.fs", "dummy", parsingOptions) |> Async.RunSynchronously |> ignore
+            checker.ParseFile("dummy.fs", SourceText.ofString "dummy", parsingOptions) |> Async.RunSynchronously |> ignore

    [<Benchmark>]
    member __.Parsing() =
@ -51,10 +143,62 @@ type CompilerServiceParsing() =
        | None, _ -> failwith "no checker"
        | _, None -> failwith "no source"
        | Some(checker), Some(source) ->
-            let results = checker.ParseFile("TypeChecker.fs", source, parsingOptions) |> Async.RunSynchronously
+            let results = checker.ParseFile("TypeChecker.fs", source.ToFSharpSourceText(), parsingOptions) |> Async.RunSynchronously
            if results.ParseHadErrors then failwithf "parse had errors: %A" results.Errors

+    [<IterationSetup(Target = "ILReading")>]
+    member __.ILReadingSetup() =
+        // With caching, performance increases an order of magnitude when re-reading an ILModuleReader.
+        // Clear it for benchmarking.
+        ClearAllILModuleReaderCache()
+
+    [<Benchmark>]
+    member __.ILReading() =
+        match assembliesOpt with
+        | None -> failwith "no assemblies"
+        | Some(assemblies) ->
+            // We try to read most of everything in the assembly that matter, mainly types with their properties, methods, and fields.
+            // CustomAttrs and SecurityDecls are lazy until you call them, so we call them here for benchmarking.
+            assemblies
+            |> Array.iter (fun (fileName) ->
+                let reader = OpenILModuleReader fileName readerOptions
+
+                let ilModuleDef = reader.ILModuleDef
+
+                let ilAssemblyManifest = ilModuleDef.Manifest.Value
+
+                ilAssemblyManifest.CustomAttrs |> ignore
+                ilAssemblyManifest.SecurityDecls |> ignore
+                ilAssemblyManifest.ExportedTypes.AsList
+                |> List.iter (fun x ->
+                   x.CustomAttrs |> ignore
+                )
+
+                ilModuleDef.CustomAttrs |> ignore
+                ilModuleDef.TypeDefs.AsArray
+                |> Array.iter (fun ilTypeDef ->
+                    ilTypeDef.CustomAttrs |> ignore
+                    ilTypeDef.SecurityDecls |> ignore
+
+                    ilTypeDef.Methods.AsArray
+                    |> Array.iter (fun ilMethodDef ->
+                        ilMethodDef.CustomAttrs |> ignore
+                        ilMethodDef.SecurityDecls |> ignore
+                    )
+
+                    ilTypeDef.Fields.AsList
+                    |> List.iter (fun ilFieldDef ->
+                        ilFieldDef.CustomAttrs |> ignore
+                    )
+
+                    ilTypeDef.Properties.AsList
+                    |> List.iter (fun ilPropertyDef ->
+                        ilPropertyDef.CustomAttrs |> ignore
+                    )
+                )
+            )
+
 [<EntryPoint>]
 let main argv =
-    let _ = BenchmarkRunner.Run<CompilerServiceParsing>()
+    let _ = BenchmarkRunner.Run<CompilerService>()
    0
--- a/benchmarks/Directory.Build.props
+++ b/benchmarks/Directory.Build.props
@ -0,0 +1,3 @@
+<Project>
+  <Import Project="$([MSBuild]::GetPathOfFileAbove('FSharp.Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
+</Project>
--- a/benchmarks/Directory.Build.targets
+++ b/benchmarks/Directory.Build.targets
@ -0,0 +1,3 @@
+<Project>
+  <Import Project="$([MSBuild]::GetPathOfFileAbove('FSharp.Directory.Build.targets', '$(MSBuildThisFileDirectory)../'))" />
+</Project>
--- a/build.sh
+++ b/build.sh
@ -13,4 +13,4 @@ while [[ -h $source ]]; do
 done

 scriptroot="$( cd -P "$( dirname "$source" )" && pwd )"
-"$scriptroot/eng/build.sh" --build $@
+"$scriptroot/eng/build.sh" --build --restore $@
--- a/eng/Build.ps1
+++ b/eng/Build.ps1
@ -34,7 +34,7 @@ param (
    # Options
    [switch][Alias('proto')]$bootstrap,
    [string]$bootstrapConfiguration = "Proto",
-    [string]$bootstrapTfm = "net46",
+    [string]$bootstrapTfm = "net472",
    [switch][Alias('bl')]$binaryLog,
    [switch]$ci,
    [switch]$official,
@ -184,12 +184,12 @@ function UpdatePath() {
    }
    TestAndAddToPath $subdir

-    TestAndAddToPath "$ArtifactsDir\bin\fsc\$configuration\net46"
-    TestAndAddToPath "$ArtifactsDir\bin\fsiAnyCpu\$configuration\net46"
+    TestAndAddToPath "$ArtifactsDir\bin\fsc\$configuration\net472"
+    TestAndAddToPath "$ArtifactsDir\bin\fsiAnyCpu\$configuration\net472"
 }

 function VerifyAssemblyVersions() {
-    $fsiPath = Join-Path $ArtifactsDir "bin\fsi\Proto\net46\fsi.exe"
+    $fsiPath = Join-Path $ArtifactsDir "bin\fsi\Proto\net472\fsi.exe"

    # Only verify versions on CI or official build
    if ($ci -or $official) {
@ -238,8 +238,8 @@ try {
        VerifyAssemblyVersions
    }

-    $desktopTargetFramework = "net46"
-    $coreclrTargetFramework = "netcoreapp2.0"
+    $desktopTargetFramework = "net472"
+    $coreclrTargetFramework = "netcoreapp2.1"

    if ($testDesktop) {
        TestUsingNUnit -testProject "$RepoRoot\tests\FSharp.Compiler.UnitTests\FSharp.Compiler.UnitTests.fsproj" -targetFramework $desktopTargetFramework
@ -266,7 +266,7 @@ try {
        UpdatePath
        $env:HOSTED_COMPILER = 1
        $env:CSC_PIPE = "$env:USERPROFILE\.nuget\packages\Microsoft.Net.Compilers\2.7.0\tools\csc.exe"
-        $env:FSCOREDLLPATH = "$ArtifactsDir\bin\fsc\$configuration\net46\FSharp.Core.dll"
+        $env:FSCOREDLLPATH = "$ArtifactsDir\bin\fsc\$configuration\net472\FSharp.Core.dll"
        $env:LINK_EXE = "$RepoRoot\tests\fsharpqa\testenv\bin\link\link.exe"
        $env:OSARCH = $env:PROCESSOR_ARCHITECTURE
        Exec-Console $perlExe """$RepoRoot\tests\fsharpqa\testenv\bin\runall.pl"" -resultsroot ""$resultsRoot"" -results $resultsLog -log $errorLog -fail $failLog -cleanup:no -procs:$env:NUMBER_OF_PROCESSORS"
--- a/eng/Versions.props
+++ b/eng/Versions.props
@ -12,18 +12,18 @@
  <!-- Version number computation -->
  <PropertyGroup>
    <PreReleaseVersionLabel>beta</PreReleaseVersionLabel>
-    <FSCoreMajorVersion>4.5</FSCoreMajorVersion>
-    <FSCorePackageVersion>$(FSCoreMajorVersion).5</FSCorePackageVersion>
+    <FSCoreMajorVersion>4.6</FSCoreMajorVersion>
+    <FSCorePackageVersion>$(FSCoreMajorVersion).2</FSCorePackageVersion>
    <FSCoreVersion>$(FSCoreMajorVersion).0</FSCoreVersion>
    <FSCoreVersion Condition="'$(OfficialBuildId)' == ''">$(FSCoreVersion).0</FSCoreVersion>
    <!-- PR builds should specify a 4-part version number -->
-    <FSPackageMajorVersion>10.2</FSPackageMajorVersion>
-    <FSPackageVersion>$(FSPackageMajorVersion).3</FSPackageVersion>
+    <FSPackageMajorVersion>10.4</FSPackageMajorVersion>
+    <FSPackageVersion>$(FSPackageMajorVersion).2</FSPackageVersion>
    <FSProductVersion>$(FSPackageVersion)</FSProductVersion>
    <FSProductVersion Condition="'$(OfficialBuildId)' == ''">$(FSProductVersion).0</FSProductVersion>
    <!-- PR builds should specify a 4-part version number -->
-    <VSMajorVersion>15</VSMajorVersion>
-    <VSMinorVersion>9</VSMinorVersion>
+    <VSMajorVersion>16</VSMajorVersion>
+    <VSMinorVersion>0</VSMinorVersion>
    <VSGeneralVersion>$(VSMajorVersion).0</VSGeneralVersion>
    <VSAssemblyVersion>$(VSMajorVersion).$(VSMinorVersion).0</VSAssemblyVersion>
    <VSAssemblyVersion Condition="'$(OfficialBuildId)' == ''">$(VSAssemblyVersion).0</VSAssemblyVersion>
@ -35,17 +35,6 @@
    <VersionPrefix Condition="'$(UseFSharpPackageVersion)' == 'true'">$(FSCorePackageVersion)</VersionPrefix>
    <VersionPrefix Condition="'$(UseFSharpProductVersion)' == 'true'">$(FSProductVersion)</VersionPrefix>
    <VersionPrefix Condition="'$(UseVsMicroBuildAssemblyVersion)' == 'true'">$(VSAssemblyVersion)</VersionPrefix>
-    <!--
-    Previous nightly versions were of the form 15.9.20190322.1, but after the arcade sdk integration, that form
-    changed to 15.9.0.1917201 which breaks the nightly upgrade.  To enable this to work for 15.9 builds we re-insert
-    the build number (date) so that it's always increasing.
-
-    THIS CHANGE SHOULD NOT FLOW INTO ANY DEV16 BRANCHES.
-    -->
-    <_BuildNumber>$(OfficialBuildId)</_BuildNumber>
-    <_BuildNumber Condition="'$(OfficialBuildId)' == ''">$([System.DateTime]::Now.ToString(yyyyMMdd)).0</_BuildNumber>
-    <VsixVersionDateStampFix>$(_BuildNumber.Split('.')[0])</VsixVersionDateStampFix>
-    <VsixVersionPrefix>$(VSMajorVersion).$(VSMinorVersion).$(VsixVersionDateStampFix)</VsixVersionPrefix>
    <AssemblyVersion Condition="'$(OfficialBuildId)' == ''">$(VersionPrefix)</AssemblyVersion>
    <!-- PR builds should explicitly specify a version number -->
  </PropertyGroup>
@ -65,12 +54,15 @@
      https://myget.org/F/vs-editor/api/v3/index.json;
      https://vside.myget.org/F/vssdk/api/v3/index.json;
      https://vside.myget.org/F/vs-impl/api/v3/index.json;
+      https://myget.org/F/roslyn_concord/api/v3/index.json;
+      https://vside.myget.org/F/devcore/api/v3/index.json;
    </RestoreSources>
    <!-- version numbers from files -->
    <RoslynPackageVersion>$([System.IO.File]::ReadAllText('$(MSBuildThisFileDirectory)..\RoslynPackageVersion.txt').Trim())</RoslynPackageVersion>
    <!-- System.* packages -->
    <SystemCollectionsImmutablePackageVersion>1.5.0</SystemCollectionsImmutablePackageVersion>
    <SystemConsolePackageVersion>4.3.0</SystemConsolePackageVersion>
+    <SystemDesignPackageVersion>4.0.0</SystemDesignPackageVersion>
    <SystemDiagnosticsProcessPackageVersion>4.3.0</SystemDiagnosticsProcessPackageVersion>
    <SystemDiagnosticsTraceSourcePackageVersion>4.3.0</SystemDiagnosticsTraceSourcePackageVersion>
    <SystemIoCompressionPackageVersion>4.3.0</SystemIoCompressionPackageVersion>
@ -109,44 +101,46 @@
    <!-- Visual Studio packages -->
    <EnvDTE80PackageVersion>8.0.1</EnvDTE80PackageVersion>
    <MicrosoftVisualFSharpMicrosoftVisualStudioShellUIInternalPackageVersion>14.0.25420</MicrosoftVisualFSharpMicrosoftVisualStudioShellUIInternalPackageVersion>
-    <MicrosoftVisualStudioCoreUtilityPackageVersion>15.8.525</MicrosoftVisualStudioCoreUtilityPackageVersion>
-    <MicrosoftVisualStudioComponentModelHostPackageVersion>15.0.26201-alpha</MicrosoftVisualStudioComponentModelHostPackageVersion>
+    <MicrosoftVisualStudioCoreUtilityPackageVersion>16.0.467</MicrosoftVisualStudioCoreUtilityPackageVersion>
+    <MicrosoftVisualStudioComponentModelHostPackageVersion>16.0.467</MicrosoftVisualStudioComponentModelHostPackageVersion>
    <MicrosoftVisualStudioDesignerInterfacesPackageVersion>1.1.4322</MicrosoftVisualStudioDesignerInterfacesPackageVersion>
-    <MicrosoftVisualStudioEditorPackageVersion>15.8.525</MicrosoftVisualStudioEditorPackageVersion>
-    <MicrosoftVisualStudioImagingPackageVersion>15.0.26201</MicrosoftVisualStudioImagingPackageVersion>
-    <MicrosoftVisualStudioLanguageStandardClassificationPackageVersion>15.8.525</MicrosoftVisualStudioLanguageStandardClassificationPackageVersion>
-    <MicrosoftVisualStudioLanguagePackageVersion>15.8.525</MicrosoftVisualStudioLanguagePackageVersion>
-    <MicrosoftVisualStudioLanguageIntellisensePackageVersion>15.8.525</MicrosoftVisualStudioLanguageIntellisensePackageVersion>
-    <MicrosoftVisualStudioManagedInterfacesPackageVersion>8.0.50727</MicrosoftVisualStudioManagedInterfacesPackageVersion>
+    <MicrosoftVisualStudioEditorPackageVersion>16.0.467</MicrosoftVisualStudioEditorPackageVersion>
+    <MicrosoftVisualStudioImageCatalogPackageVersion>16.0.28727</MicrosoftVisualStudioImageCatalogPackageVersion>
+    <MicrosoftVisualStudioImagingPackageVersion>16.0.28729</MicrosoftVisualStudioImagingPackageVersion>
+    <MicrosoftVisualStudioLanguageStandardClassificationPackageVersion>16.0.467</MicrosoftVisualStudioLanguageStandardClassificationPackageVersion>
+    <MicrosoftVisualStudioLanguagePackageVersion>16.0.467</MicrosoftVisualStudioLanguagePackageVersion>
+    <MicrosoftVisualStudioLanguageIntellisensePackageVersion>16.0.467</MicrosoftVisualStudioLanguageIntellisensePackageVersion>
+    <MicrosoftVisualStudioManagedInterfacesPackageVersion>8.0.50728</MicrosoftVisualStudioManagedInterfacesPackageVersion>
    <MicrosoftVisualStudioOLEInteropPackageVersion>7.10.6071</MicrosoftVisualStudioOLEInteropPackageVersion>
-    <MicrosoftVisualStudioPackageLanguageService150PackageVersion>15.0.26201</MicrosoftVisualStudioPackageLanguageService150PackageVersion>
-    <MicrosoftVisualStudioProjectAggregatorPackageVersion>8.0.50727</MicrosoftVisualStudioProjectAggregatorPackageVersion>
+    <MicrosoftVisualStudioPackageLanguageService150PackageVersion>16.0.28729</MicrosoftVisualStudioPackageLanguageService150PackageVersion>
+    <MicrosoftVisualStudioProjectAggregatorPackageVersion>8.0.50728</MicrosoftVisualStudioProjectAggregatorPackageVersion>
+    <MicrosoftVisualStudioProjectSystemVersion>16.0.201-pre-g7d366164d0</MicrosoftVisualStudioProjectSystemVersion>
    <MicrosoftVisualStudioProjectSystemManagedVersion>2.3.6152103</MicrosoftVisualStudioProjectSystemManagedVersion>
    <MicrosoftVisualStudioShell140PackageVersion>14.3.25407</MicrosoftVisualStudioShell140PackageVersion>
-    <MicrosoftVisualStudioShell150PackageVersion>15.0.26201</MicrosoftVisualStudioShell150PackageVersion>
-    <MicrosoftVisualStudioShellDesignPackageVersion>15.0.26201</MicrosoftVisualStudioShellDesignPackageVersion>
-    <MicrosoftVisualStudioShellFrameworkPackageVersion>15.9.28307</MicrosoftVisualStudioShellFrameworkPackageVersion>
+    <MicrosoftVisualStudioShell150PackageVersion>16.0.28729</MicrosoftVisualStudioShell150PackageVersion>
+    <MicrosoftVisualStudioShellDesignPackageVersion>16.0.28729</MicrosoftVisualStudioShellDesignPackageVersion>
+    <MicrosoftVisualStudioShellFrameworkPackageVersion>16.0.28729</MicrosoftVisualStudioShellFrameworkPackageVersion>
    <MicrosoftVisualStudioShellImmutable100PackageVersion>10.0.30319</MicrosoftVisualStudioShellImmutable100PackageVersion>
    <MicrosoftVisualStudioShellImmutable110PackageVersion>11.0.50727</MicrosoftVisualStudioShellImmutable110PackageVersion>
    <MicrosoftVisualStudioShellImmutable150PackageVersion>15.0.25123-Dev15Preview</MicrosoftVisualStudioShellImmutable150PackageVersion>
    <MicrosoftVisualStudioShellInteropPackageVersion>7.10.6072</MicrosoftVisualStudioShellInteropPackageVersion>
-    <MicrosoftVisualStudioShellInterop80PackageVersion>8.0.50727</MicrosoftVisualStudioShellInterop80PackageVersion>
-    <MicrosoftVisualStudioShellInterop90PackageVersion>9.0.30729</MicrosoftVisualStudioShellInterop90PackageVersion>
-    <MicrosoftVisualStudioShellInterop100PackageVersion>10.0.30319</MicrosoftVisualStudioShellInterop100PackageVersion>
-    <MicrosoftVisualStudioShellInterop110PackageVersion>11.0.61030</MicrosoftVisualStudioShellInterop110PackageVersion>
-    <MicrosoftVisualStudioShellInterop120PackageVersion>12.0.30110</MicrosoftVisualStudioShellInterop120PackageVersion>
-    <MicrosoftVisualStudioTextDataPackageVersion>15.8.525</MicrosoftVisualStudioTextDataPackageVersion>
+    <MicrosoftVisualStudioShellInterop80PackageVersion>8.0.50728</MicrosoftVisualStudioShellInterop80PackageVersion>
+    <MicrosoftVisualStudioShellInterop90PackageVersion>9.0.30730</MicrosoftVisualStudioShellInterop90PackageVersion>
+    <MicrosoftVisualStudioShellInterop100PackageVersion>10.0.30320</MicrosoftVisualStudioShellInterop100PackageVersion>
+    <MicrosoftVisualStudioShellInterop110PackageVersion>11.0.61031</MicrosoftVisualStudioShellInterop110PackageVersion>
+    <MicrosoftVisualStudioShellInterop120PackageVersion>12.0.30111</MicrosoftVisualStudioShellInterop120PackageVersion>
+    <MicrosoftVisualStudioTextDataPackageVersion>16.0.467</MicrosoftVisualStudioTextDataPackageVersion>
    <MicrosoftVisualStudioTextManagerInteropPackageVersion>7.10.6071</MicrosoftVisualStudioTextManagerInteropPackageVersion>
-    <MicrosoftVisualStudioTextManagerInterop80PackageVersion>8.0.50727</MicrosoftVisualStudioTextManagerInterop80PackageVersion>
-    <MicrosoftVisualStudioTextManagerInterop100PackageVersion>10.0.30319</MicrosoftVisualStudioTextManagerInterop100PackageVersion>
+    <MicrosoftVisualStudioTextManagerInterop80PackageVersion>8.0.50728</MicrosoftVisualStudioTextManagerInterop80PackageVersion>
+    <MicrosoftVisualStudioTextManagerInterop100PackageVersion>10.0.30320</MicrosoftVisualStudioTextManagerInterop100PackageVersion>
    <MicrosoftVisualStudioTextManagerInterop120PackageVersion>12.0.30112</MicrosoftVisualStudioTextManagerInterop120PackageVersion>
-    <MicrosoftVisualStudioTextUIPackageVersion>15.8.525</MicrosoftVisualStudioTextUIPackageVersion>
-    <MicrosoftVisualStudioTextUIWpfPackageVersion>15.8.525</MicrosoftVisualStudioTextUIWpfPackageVersion>
-    <MicrosoftVisualStudioThreadingPackageVersion>15.8.209</MicrosoftVisualStudioThreadingPackageVersion>
-    <MicrosoftVisualStudioUtilitiesPackageVersion>15.0.26201</MicrosoftVisualStudioUtilitiesPackageVersion>
-    <MicrosoftVisualStudioValidationPackageVersion>15.3.15</MicrosoftVisualStudioValidationPackageVersion>
+    <MicrosoftVisualStudioTextUIPackageVersion>16.0.467</MicrosoftVisualStudioTextUIPackageVersion>
+    <MicrosoftVisualStudioTextUIWpfPackageVersion>16.0.467</MicrosoftVisualStudioTextUIWpfPackageVersion>
+    <MicrosoftVisualStudioThreadingPackageVersion>16.0.102</MicrosoftVisualStudioThreadingPackageVersion>
+    <MicrosoftVisualStudioUtilitiesPackageVersion>16.0.28729</MicrosoftVisualStudioUtilitiesPackageVersion>
+    <MicrosoftVisualStudioValidationPackageVersion>15.3.58</MicrosoftVisualStudioValidationPackageVersion>
    <MicrosoftVisualStudioWCFReferenceInteropPackageVersion>9.0.30729</MicrosoftVisualStudioWCFReferenceInteropPackageVersion>
-    <MicrosoftVSSDKBuildToolsVersion>15.7.109</MicrosoftVSSDKBuildToolsVersion>
+    <MicrosoftVSSDKBuildToolsVersion>16.0.2264</MicrosoftVSSDKBuildToolsVersion>
    <VSSDKDebuggerVisualizersPackageVersion>12.0.4</VSSDKDebuggerVisualizersPackageVersion>
    <VSSDKVSLangProjPackageVersion>7.0.4</VSSDKVSLangProjPackageVersion>
    <VSSDKVSLangProj8PackageVersion>8.0.4</VSSDKVSLangProj8PackageVersion>
--- a/eng/build-utils.ps1
+++ b/eng/build-utils.ps1
@ -13,10 +13,10 @@ $binaryLog = if (Test-Path variable:binaryLog) { $binaryLog } else { $false }
 $nodeReuse = if (Test-Path variable:nodeReuse) { $nodeReuse } else { $false }
 $bootstrapDir = if (Test-Path variable:bootstrapDir) { $bootstrapDir } else { "" }
 $bootstrapConfiguration = if (Test-Path variable:bootstrapConfiguration) { $bootstrapConfiguration } else { "Proto" }
-$bootstrapTfm = if (Test-Path variable:bootstrapTfm) { $bootstrapTfm } else { "net46" }
+$bootstrapTfm = if (Test-Path variable:bootstrapTfm) { $bootstrapTfm } else { "net472" }
 $properties = if (Test-Path variable:properties) { $properties } else { @() }

-function GetProjectOutputBinary([string]$fileName, [string]$projectName = "", [string]$configuration = $script:configuration, [string]$tfm = "net46", [string]$rid = "", [bool]$published = $false) {
+function GetProjectOutputBinary([string]$fileName, [string]$projectName = "", [string]$configuration = $script:configuration, [string]$tfm = "net472", [string]$rid = "", [bool]$published = $false) {
  $projectName = if ($projectName -ne "") { $projectName } else { [System.IO.Path]::GetFileNameWithoutExtension($fileName) }
  $publishDir = if ($published) { "publish\" } else { "" }
  $ridDir = if ($rid -ne "") { "$rid\" } else { "" }
--- a/eng/build.sh
+++ b/eng/build.sh
@ -240,9 +240,10 @@ InitializeDotNetCli $restore
 BuildSolution

 if [[ "$test_core_clr" == true ]]; then
-  TestUsingNUnit --testproject "$repo_root/tests/FSharp.Compiler.UnitTests/FSharp.Compiler.UnitTests.fsproj" --targetframework netcoreapp2.0
-  TestUsingNUnit --testproject "$repo_root/tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj" --targetframework netcoreapp2.0
-  TestUsingNUnit --testproject "$repo_root/tests/FSharp.Core.UnitTests/FSharp.Core.UnitTests.fsproj" --targetframework netcoreapp2.0
+  coreclrtestframework=netcoreapp2.1
+  TestUsingNUnit --testproject "$repo_root/tests/FSharp.Compiler.UnitTests/FSharp.Compiler.UnitTests.fsproj" --targetframework $coreclrtestframework
+  TestUsingNUnit --testproject "$repo_root/tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj" --targetframework $coreclrtestframework
+  TestUsingNUnit --testproject "$repo_root/tests/FSharp.Core.UnitTests/FSharp.Core.UnitTests.fsproj" --targetframework $coreclrtestframework
 fi

 ExitWithExitCode 0
--- a/fcs/FSharp.Compiler.Service.MSBuild.v12/FSharp.Compiler.Service.MSBuild.v12.fsproj
+++ b/fcs/FSharp.Compiler.Service.MSBuild.v12/FSharp.Compiler.Service.MSBuild.v12.fsproj
@ -29,6 +29,9 @@
    <Reference Include="System.Runtime" />
    <Reference Include="System.IO" />
    <PackageReference Include="FSharp.Core" Version="4.6.2" />
+    <PackageReference Include="FSharp.Core" Version="4.5.2" />
+    <PackageReference Include="FSharp.Core" Version="4.1.19" />
+    <PackageReference Include="FSharp.Core" Version="4.1.18" />
    <ProjectReference Include="..\FSharp.Compiler.Service\FSharp.Compiler.Service.fsproj" />
    <Reference Include="Microsoft.Build.Framework, Version=12.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
      <HintPath>$(FSharpSourcesRoot)\..\fcs\dependencies\MSBuild.v12.0\Microsoft.Build.Framework.dll</HintPath>
--- a/fcs/FSharp.Compiler.Service.ProjectCracker/FSharp.Compiler.Service.ProjectCracker.fsproj
+++ b/fcs/FSharp.Compiler.Service.ProjectCracker/FSharp.Compiler.Service.ProjectCracker.fsproj
@ -28,6 +28,9 @@
    <Reference Include="System.Runtime" />
    <Reference Include="System.IO" />
    <PackageReference Include="FSharp.Core" Version="4.6.2" />
+    <PackageReference Include="FSharp.Core" Version="4.5.2" />
+    <PackageReference Include="FSharp.Core" Version="4.1.19" />
+    <PackageReference Include="FSharp.Core" Version="4.1.18" />
    <ProjectReference Include="..\FSharp.Compiler.Service\FSharp.Compiler.Service.fsproj" />
  </ItemGroup>
 </Project>
--- a/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
+++ b/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
@ -7,10 +7,12 @@
  <PropertyGroup>
    <TargetFrameworks>net461;netcoreapp2.0</TargetFrameworks>
    <DisableImplicitFSharpCoreReference>true</DisableImplicitFSharpCoreReference>
+    <DefaultFSharpPackageVersion>4.1.19</DefaultFSharpPackageVersion>
    <NoWarn>$(NoWarn);44;75;</NoWarn>
    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
    <GenerateDocumentationFile>true</GenerateDocumentationFile>
    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
    <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies> <!-- Tests won't run without this, at least on OSX, see https://github.com/NuGet/Home/issues/4837#issuecomment-354536302 -->
  </PropertyGroup>
  <PropertyGroup Condition="'$(TargetFramework)' == 'netcoreapp2.0'">
--- a/fcs/FSharp.Compiler.Service/FSharp.Compiler.Service.fsproj
+++ b/fcs/FSharp.Compiler.Service/FSharp.Compiler.Service.fsproj
@ -639,6 +639,7 @@
  </ItemGroup>
  <ItemGroup>
    <PackageReference Include="FSharp.Core" Version="4.6.2" />
+   <PackageReference Include="FSharp.Core" Version="4.5.2" />
    <PackageReference Include="System.Collections.Immutable" Version="1.5.0" />
    <PackageReference Include="System.Reflection.Metadata" Version="1.6.0" />
  </ItemGroup>
--- a/fcs/samples/EditorService/EditorService.fsproj
+++ b/fcs/samples/EditorService/EditorService.fsproj
@ -13,6 +13,8 @@
  </ItemGroup>
  <ItemGroup>
    <PackageReference Include="FSharp.Core" Version="4.6.2" />
+    <PackageReference Include="FSharp.Core" Version="4.5.2" />
+    <PackageReference Include="FSharp.Core" Version="4.1.19" />
    <ProjectReference Include="..\..\FSharp.Compiler.Service\FSharp.Compiler.Service.fsproj" />
    <PackageReference Include="System.Reflection.Metadata" Version="1.6.0" />
  </ItemGroup>
--- a/fcs/samples/EditorService/Program.fs
+++ b/fcs/samples/EditorService/Program.fs
@ -8,6 +8,7 @@ open FSharp.Compiler.QuickParse
 let checker = FSharpChecker.Create()

 let parseWithTypeInfo (file, input) = 
+    let input = FSharp.Compiler.Text.SourceText.ofString input
    let checkOptions, _errors = checker.GetProjectOptionsFromScript(file, input) |> Async.RunSynchronously
    let parsingOptions, _errors = checker.GetParsingOptionsFromProjectOptions(checkOptions)
    let untypedRes = checker.ParseFile(file, input, parsingOptions) |> Async.RunSynchronously
--- a/fcs/samples/FscExe/FscExe.fsproj
+++ b/fcs/samples/FscExe/FscExe.fsproj
@ -15,6 +15,8 @@
  <ItemGroup>
    <Reference Include="System.Runtime.Remoting" />
    <PackageReference Include="FSharp.Core" Version="4.6.2" />
+    <PackageReference Include="FSharp.Core" Version="4.5.2" />
+    <PackageReference Include="FSharp.Core" Version="4.1.19" />
    <ProjectReference Include="..\..\FSharp.Compiler.Service\FSharp.Compiler.Service.fsproj" />
  </ItemGroup>
  <ItemGroup Condition="'$(TargetFramework)' == 'net461'">
--- a/fcs/samples/FsiExe/FsiExe.fsproj
+++ b/fcs/samples/FsiExe/FsiExe.fsproj
@ -17,6 +17,8 @@
    <Reference Include="System.Runtime.Remoting" />
    <Reference Include="System.Windows.Forms" />
    <PackageReference Include="FSharp.Core" Version="4.6.2" />
+    <PackageReference Include="FSharp.Core" Version="4.5.2" />
+    <PackageReference Include="FSharp.Core" Version="4.1.19" />
    <ProjectReference Include="..\..\FSharp.Compiler.Service\FSharp.Compiler.Service.fsproj" />
  </ItemGroup>
  <ItemGroup Condition="'$(TargetFramework)' == 'net461'">
--- a/fcs/samples/InteractiveService/InteractiveService.fsproj
+++ b/fcs/samples/InteractiveService/InteractiveService.fsproj
@ -13,6 +13,8 @@
  </ItemGroup>
  <ItemGroup>
    <PackageReference Include="FSharp.Core" Version="4.6.2" />
+    <PackageReference Include="FSharp.Core" Version="4.5.2" />
+    <PackageReference Include="FSharp.Core" Version="4.1.19" />
    <ProjectReference Include="..\..\FSharp.Compiler.Service\FSharp.Compiler.Service.fsproj" />
  </ItemGroup>
  <ItemGroup Condition="'$(TargetFramework)' == 'net461'">
--- a/fcs/samples/Tokenizer/Tokenizer.fsproj
+++ b/fcs/samples/Tokenizer/Tokenizer.fsproj
@ -13,6 +13,8 @@
  </ItemGroup>
  <ItemGroup>
    <PackageReference Include="FSharp.Core" Version="4.6.2" />
+    <PackageReference Include="FSharp.Core" Version="4.5.2" />
+    <PackageReference Include="FSharp.Core" Version="4.1.19" />
    <ProjectReference Include="..\..\FSharp.Compiler.Service\FSharp.Compiler.Service.fsproj" />
  </ItemGroup>
  <ItemGroup Condition="'$(TargetFramework)' == 'net461'">
--- a/fcs/samples/UntypedTree/Program.fs
+++ b/fcs/samples/UntypedTree/Program.fs
@ -11,7 +11,7 @@ let checker = FSharpChecker.Create()
 // Get untyped tree for a specified input
 let getUntypedTree (file, input) = 
  let parsingOptions = { FSharpParsingOptions.Default with SourceFiles = [| file |] }
-  let untypedRes = checker.ParseFile(file, input, parsingOptions) |> Async.RunSynchronously
+  let untypedRes = checker.ParseFile(file, FSharp.Compiler.Text.SourceText.ofString input, parsingOptions) |> Async.RunSynchronously
  match untypedRes.ParseTree with
  | Some tree -> tree
  | None -> failwith "Something went wrong during parsing!"
--- a/fcs/samples/UntypedTree/UntypedTree.fsproj
+++ b/fcs/samples/UntypedTree/UntypedTree.fsproj
@ -13,6 +13,8 @@
  </ItemGroup>
  <ItemGroup>
    <PackageReference Include="FSharp.Core" Version="4.6.2" />
+    <PackageReference Include="FSharp.Core" Version="4.5.2" />
+    <PackageReference Include="FSharp.Core" Version="4.1.29" />
    <ProjectReference Include="..\..\FSharp.Compiler.Service\FSharp.Compiler.Service.fsproj" />
  </ItemGroup>
  <ItemGroup Condition="'$(TargetFramework)' == 'net461'">
--- a/global.json
+++ b/global.json
@ -2,7 +2,7 @@
  "tools": {
    "dotnet": "2.1.504",
    "vs": {
-      "version": "15.9",
+      "version": "16.0",
      "components": [
        "Microsoft.Net.Core.Component.SDK.2.1",
        "Microsoft.VisualStudio.Component.FSharp"
--- a/proto.proj
+++ b/proto.proj
@ -7,15 +7,15 @@

  <ItemGroup>
    <Projects Include="src\fsharp\FSharp.Build\FSharp.Build.fsproj">
-      <AdditionalProperties Condition="'$(OS)' != 'Unix'">TargetFramework=net46</AdditionalProperties>
+      <AdditionalProperties Condition="'$(OS)' != 'Unix'">TargetFramework=net472</AdditionalProperties>
      <AdditionalProperties Condition="'$(OS)' == 'Unix'">TargetFramework=netcoreapp2.1</AdditionalProperties>
    </Projects>
    <Projects Include="src\fsharp\fsc\fsc.fsproj">
-      <AdditionalProperties Condition="'$(OS)' != 'Unix'">TargetFramework=net46</AdditionalProperties>
+      <AdditionalProperties Condition="'$(OS)' != 'Unix'">TargetFramework=net472</AdditionalProperties>
      <AdditionalProperties Condition="'$(OS)' == 'Unix'">TargetFramework=netcoreapp2.1</AdditionalProperties>
    </Projects>
    <Projects Include="src\fsharp\fsi\fsi.fsproj">
-      <AdditionalProperties Condition="'$(OS)' != 'Unix'">TargetFramework=net46</AdditionalProperties>
+      <AdditionalProperties Condition="'$(OS)' != 'Unix'">TargetFramework=net472</AdditionalProperties>
      <AdditionalProperties Condition="'$(OS)' == 'Unix'">TargetFramework=netcoreapp2.1</AdditionalProperties>
    </Projects>
  </ItemGroup>
--- a/scripts/verify-translations.cmd
+++ b/scripts/verify-translations.cmd
@ -1,3 +1,3 @@
@echo off

-%~dp0..\artifacts\bin\fsi\Release\net46\fsi.exe %~dp0VerifyAllTranslations.fsx -- %~dp0
+%~dp0..\artifacts\bin\fsi\Release\net472\fsi.exe %~dp0VerifyAllTranslations.fsx -- %~dp0
--- a/setup/Swix/Microsoft.FSharp.Compiler.MSBuild/Microsoft.FSharp.Compiler.MSBuild.csproj
+++ b/setup/Swix/Microsoft.FSharp.Compiler.MSBuild/Microsoft.FSharp.Compiler.MSBuild.csproj
@ -1,8 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net46</TargetFramework>
-    <AssetTargetFallback>net462</AssetTargetFallback><!-- type providers redist relies on this -->
+    <TargetFramework>net472</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
@ -108,7 +107,6 @@ folder "InstallDir:Common7\IDE\CommonExtensions\Microsoft\FSharp"
  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\$(TargetFramework)\Microsoft.Portable.FSharp.Targets"
  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\$(TargetFramework)\System.Collections.Immutable.dll"
  file source="$(BinariesFolder)\FSharp.Compiler.Private\$(Configuration)\$(TargetFramework)\System.Reflection.Metadata.dll"
-  file source="$(BinariesFolder)\FSharp.Compiler.Private\$(Configuration)\$(TargetFramework)\System.ValueTuple.dll"
  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\$(TargetFramework)\Microsoft.FSharp.NetSdk.props"
  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\$(TargetFramework)\Microsoft.FSharp.NetSdk.targets"
  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\$(TargetFramework)\Microsoft.FSharp.Overrides.NetSdk.targets"
--- a/setup/Swix/Microsoft.FSharp.Dependencies/Microsoft.FSharp.Dependencies.csproj
+++ b/setup/Swix/Microsoft.FSharp.Dependencies/Microsoft.FSharp.Dependencies.csproj
@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net46</TargetFramework>
+    <TargetFramework>net472</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
--- a/setup/Swix/Microsoft.FSharp.IDE/Microsoft.FSharp.IDE.csproj
+++ b/setup/Swix/Microsoft.FSharp.IDE/Microsoft.FSharp.IDE.csproj
@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net46</TargetFramework>
+    <TargetFramework>net472</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
--- a/setup/Swix/Microsoft.FSharp.SDK/Microsoft.FSharp.SDK.csproj
+++ b/setup/Swix/Microsoft.FSharp.SDK/Microsoft.FSharp.SDK.csproj
@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net46</TargetFramework>
+    <TargetFramework>net472</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
--- a/src/absil/ilread.fs
+++ b/src/absil/ilread.fs
@ -4003,6 +4003,8 @@ let OpenILModuleReaderFromBytes fileName bytes opts =
    let ilModule, ilAssemblyRefs, pdb = openPE (fileName, pefile, opts.pdbDirPath, (opts.reduceMemoryUsage = ReduceMemoryFlag.Yes), opts.ilGlobals, true)
    new ILModuleReaderImpl(ilModule, ilAssemblyRefs, (fun () -> ClosePdbReader pdb)) :> ILModuleReader

+let ClearAllILModuleReaderCache() = ilModuleReaderCache.Clear(ILModuleReaderCacheLockToken())
+
 let OpenILModuleReader fileName opts = 
    // Pseudo-normalize the paths.
    let (ILModuleReaderCacheKey (fullPath,writeStamp,_,_,_,_) as key), keyOk = 
--- a/src/absil/ilread.fsi
+++ b/src/absil/ilread.fsi
@ -80,6 +80,8 @@ type ILModuleReader =
 /// PDB files may not be read with this option. 
 val internal OpenILModuleReader: string -> ILReaderOptions -> ILModuleReader

+val internal ClearAllILModuleReaderCache : unit -> unit
+
 /// Open a binary reader based on the given bytes. 
 val internal OpenILModuleReaderFromBytes: fileNameForDebugOutput:string -> assemblyContents: byte[] -> options: ILReaderOptions -> ILModuleReader

--- a/src/buildfromsource/BuildFromSource.targets
+++ b/src/buildfromsource/BuildFromSource.targets
@ -3,7 +3,7 @@
 <Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">

  <PropertyGroup>
-    <FSCoreVersion>4.5.0.0</FSCoreVersion>
+    <FSCoreVersion>4.6.0.0</FSCoreVersion>
    <OutputPath>$(MSBuildThisFileDirectory)../../BuildFromSource/$(Configuration)/bin</OutputPath>
    <FSharpSourcesRoot>$(MSBuildThisFileDirectory)..</FSharpSourcesRoot>

--- a/src/buildfromsource/FSharp.Build/AssemblyInfo.fs
+++ b/src/buildfromsource/FSharp.Build/AssemblyInfo.fs
@ -8,7 +8,7 @@ open System.Reflection
 [<assembly:AssemblyTitle("FSharp.Build.dll")>]
 [<assembly:AssemblyCopyright("\169 Microsoft Corporation.  All Rights Reserved.")>]
 [<assembly:AssemblyProduct("Microsoft\174 F#")>]
-[<assembly:AssemblyInformationalVersion("10.2.0.0")>]
-[<assembly:AssemblyVersion("10.2.0.0")>]
+[<assembly:AssemblyInformationalVersion("10.4.0.0")>]
+[<assembly:AssemblyVersion("10.4.0.0")>]
 [<assembly:AssemblyFileVersion("2018.05.22.0")>]
 do()
--- a/src/buildfromsource/FSharp.Compiler.Interactive.Settings/AssemblyInfo.fs
+++ b/src/buildfromsource/FSharp.Compiler.Interactive.Settings/AssemblyInfo.fs
@ -10,7 +10,7 @@ open System.Runtime.InteropServices
 [<assembly:AssemblyCopyright("\169 Microsoft Corporation.  All Rights Reserved.")>]
 [<assembly:AssemblyProduct("Microsoft\174 F#")>]
 [<assembly:ComVisible(false)>]
-[<assembly:AssemblyInformationalVersion("10.2.0.0")>]
-[<assembly:AssemblyVersion("10.2.0.0")>]
+[<assembly:AssemblyInformationalVersion("10.4.0.0")>]
+[<assembly:AssemblyVersion("10.4.0.0")>]
 [<assembly:AssemblyFileVersion("2018.05.22.0")>]
 do()
--- a/src/buildfromsource/FSharp.Compiler.Private/AssemblyInfo.fs
+++ b/src/buildfromsource/FSharp.Compiler.Private/AssemblyInfo.fs
@ -10,7 +10,7 @@ open System.Runtime.InteropServices
 [<assembly:AssemblyCopyright("\169 Microsoft Corporation.  All Rights Reserved.")>]
 [<assembly:AssemblyProduct("Microsoft\174 F#")>]
 [<assembly:ComVisible(false)>]
-[<assembly:AssemblyInformationalVersion("10.2.0.0")>]
-[<assembly:AssemblyVersion("10.2.0.0")>]
+[<assembly:AssemblyInformationalVersion("10.4.0.0")>]
+[<assembly:AssemblyVersion("10.4.0.0")>]
 [<assembly:AssemblyFileVersion("2018.05.22.0")>]
 do()
--- a/src/buildfromsource/FSharp.Compiler.nuget/FSharp.Compiler.nuget.fsproj
+++ b/src/buildfromsource/FSharp.Compiler.nuget/FSharp.Compiler.nuget.fsproj
@ -20,7 +20,7 @@
    <PackageAuthors    Condition="'$(PackageAuthors)' == ''"   >Microsoft and F# Software Foundation</PackageAuthors> 
    <PackageTags       Condition="'$(PackageTags)' == ''"      >Visual F# Compiler FSharp functional programming</PackageTags> 
    <PreReleaseSuffix  Condition="'$(PreRelease)' != 'false'">-rc-$(BuildRevision.Trim())-0</PreReleaseSuffix>
-    <PackageVersion>10.2.0$(PreReleaseSuffix)</PackageVersion>
+    <PackageVersion>10.4.0$(PreReleaseSuffix)</PackageVersion>
    <PackageProperties>-prop "licenseUrl=$(PackageLicenceUrl)" -prop "version=$(PackageVersion)" -prop "authors=$(PackageAuthors)" -prop "projectUrl=$(PackageProjectUrl)" -prop "tags=$(PackageTags)"</PackageProperties>
  </PropertyGroup>

--- a/src/buildfromsource/FSharp.Core/AssemblyInfo.fs
+++ b/src/buildfromsource/FSharp.Core/AssemblyInfo.fs
@ -16,8 +16,8 @@ open System.Runtime.InteropServices
 [<assembly:AssemblyFlags(System.Reflection.AssemblyNameFlags.Retargetable)>]
 #endif

-[<assembly:AssemblyInformationalVersion("4.5.0.0")>]
-[<assembly:AssemblyVersion("4.5.0.0")>]
+[<assembly:AssemblyInformationalVersion("4.6.0.0")>]
+[<assembly:AssemblyVersion("4.6.0.0")>]
 [<assembly:AssemblyFileVersion("2018.05.23.0")>]
 do()

--- a/src/buildfromsource/Fsc/AssemblyInfo.fs
+++ b/src/buildfromsource/Fsc/AssemblyInfo.fs
@ -10,7 +10,7 @@ open System.Runtime.InteropServices
 [<assembly:AssemblyCopyright("\169 Microsoft Corporation.  All Rights Reserved.")>]
 [<assembly:AssemblyProduct("Microsoft\174 F#")>]
 [<assembly:ComVisible(false)>]
-[<assembly:AssemblyInformationalVersion("10.2.0.0")>]
-[<assembly:AssemblyVersion("10.2.0.0")>]
+[<assembly:AssemblyInformationalVersion("10.4.0.0")>]
+[<assembly:AssemblyVersion("10.4.0.0")>]
 [<assembly:AssemblyFileVersion("2018.05.22.0")>]
 do()
--- a/src/buildfromsource/Fsi/AssemblyInfo.fs
+++ b/src/buildfromsource/Fsi/AssemblyInfo.fs
@ -7,7 +7,7 @@ open System.Reflection
 [<assembly:AssemblyTitle("fsi.exe")>]
 [<assembly:AssemblyCopyright("\169 Microsoft Corporation.  All Rights Reserved.")>]
 [<assembly:AssemblyProduct("Microsoft\174 F#")>]
-[<assembly:AssemblyInformationalVersion("10.2.0.0")>]
-[<assembly:AssemblyVersion("10.2.0.0")>]
+[<assembly:AssemblyInformationalVersion("10.4.0.0")>]
+[<assembly:AssemblyVersion("10.4.0.0")>]
 [<assembly:AssemblyFileVersion("2018.05.22.0")>]
 do()
--- a/src/fsharp/CheckFormatStrings.fs
+++ b/src/fsharp/CheckFormatStrings.fs
@ -54,15 +54,17 @@ let parseFormatStringInternal (m:range) (g: TcGlobals) (context: FormatStringChe
    let (offset, fmt) = 
        match context with
        | Some context ->
-            let length = context.Source.Length
-            if m.EndLine < context.LineStartPositions.Length then
-                let startIndex = context.LineStartPositions.[m.StartLine-1] + m.StartColumn
-                let endIndex = context.LineStartPositions.[m.EndLine-1] + m.EndColumn - 1
-                if startIndex < length-3 && context.Source.[startIndex..startIndex+2] = "\"\"\"" then
-                    (3, context.Source.[startIndex+3..endIndex-3])
-                elif startIndex < length-2 && context.Source.[startIndex..startIndex+1] = "@\"" then
-                    (2, context.Source.[startIndex+2..endIndex-1])
-                else (1, context.Source.[startIndex+1..endIndex-1])
+            let sourceText = context.SourceText
+            let lineStartPositions = context.LineStartPositions
+            let length = sourceText.Length
+            if m.EndLine < lineStartPositions.Length then
+                let startIndex = lineStartPositions.[m.StartLine-1] + m.StartColumn
+                let endIndex = lineStartPositions.[m.EndLine-1] + m.EndColumn - 1
+                if startIndex < length-3 && sourceText.SubTextEquals("\"\"\"", startIndex) then
+                    (3, sourceText.GetSubTextString(startIndex + 3, endIndex - startIndex))
+                elif startIndex < length-2 && sourceText.SubTextEquals("@\"", startIndex) then
+                    (2, sourceText.GetSubTextString(startIndex + 2, endIndex + 1 - startIndex))
+                else (1, sourceText.GetSubTextString(startIndex + 1, endIndex - startIndex))
            else (1, fmt)
        | None -> (1, fmt)

--- a/src/fsharp/CompileOps.fs
+++ b/src/fsharp/CompileOps.fs
@ -14,15 +14,15 @@ open Internal.Utilities.Collections
 open Internal.Utilities.Filename
 open Internal.Utilities.Text

-open FSharp.Compiler.AbstractIL 
-open FSharp.Compiler.AbstractIL.IL 
+open FSharp.Compiler.AbstractIL
+open FSharp.Compiler.AbstractIL.IL
 open FSharp.Compiler.AbstractIL.ILBinaryReader
-open FSharp.Compiler.AbstractIL.Internal 
-open FSharp.Compiler.AbstractIL.Internal.Library 
+open FSharp.Compiler.AbstractIL.Internal
+open FSharp.Compiler.AbstractIL.Internal.Library
 open FSharp.Compiler.AbstractIL.Extensions.ILX
-open FSharp.Compiler.AbstractIL.Diagnostics 
+open FSharp.Compiler.AbstractIL.Diagnostics

-open FSharp.Compiler 
+open FSharp.Compiler
 open FSharp.Compiler.Ast
 open FSharp.Compiler.AttributeChecking
 open FSharp.Compiler.ConstraintSolver
@ -44,6 +44,7 @@ open FSharp.Compiler.TypeChecker
 open FSharp.Compiler.Tast
 open FSharp.Compiler.Tastops
 open FSharp.Compiler.TcGlobals
+open FSharp.Compiler.Text

 open FSharp.Compiler.DotNetFrameworkDependencies

@ -599,7 +600,7 @@ let getErrorString key = SR.GetString key

 let (|InvalidArgument|_|) (exn: exn) = match exn with :? ArgumentException as e -> Some e.Message | _ -> None

-let OutputPhasedErrorR (os: StringBuilder) (err: PhasedDiagnostic) =
+let OutputPhasedErrorR (os: StringBuilder) (err: PhasedDiagnostic) (suggestNames: bool) =

    let rec OutputExceptionR (os: StringBuilder) error = 

@ -643,16 +644,16 @@ let OutputPhasedErrorR (os: StringBuilder) (err: PhasedDiagnostic) =
          let t1, t2, _cxs = NicePrint.minimalStringsOfTwoTypes denv t1 t2
          
          match contextInfo with
-          | ContextInfo.IfExpression range when range = m -> os.Append(FSComp.SR.ifExpression(t1, t2)) |> ignore
-          | ContextInfo.CollectionElement (isArray, range) when range = m -> 
+          | ContextInfo.IfExpression range when Range.equals range m -> os.Append(FSComp.SR.ifExpression(t1, t2)) |> ignore
+          | ContextInfo.CollectionElement (isArray, range) when Range.equals range m -> 
            if isArray then
                os.Append(FSComp.SR.arrayElementHasWrongType(t1, t2)) |> ignore
            else
                os.Append(FSComp.SR.listElementHasWrongType(t1, t2)) |> ignore
-          | ContextInfo.OmittedElseBranch range when range = m -> os.Append(FSComp.SR.missingElseBranch(t2)) |> ignore
-          | ContextInfo.ElseBranchResult range when range = m -> os.Append(FSComp.SR.elseBranchHasWrongType(t1, t2)) |> ignore
-          | ContextInfo.FollowingPatternMatchClause range when range = m -> os.Append(FSComp.SR.followingPatternMatchClauseHasWrongType(t1, t2)) |> ignore
-          | ContextInfo.PatternMatchGuard range when range = m -> os.Append(FSComp.SR.patternMatchGuardIsNotBool(t2)) |> ignore
+          | ContextInfo.OmittedElseBranch range when Range.equals range m -> os.Append(FSComp.SR.missingElseBranch(t2)) |> ignore
+          | ContextInfo.ElseBranchResult range when Range.equals range m -> os.Append(FSComp.SR.elseBranchHasWrongType(t1, t2)) |> ignore
+          | ContextInfo.FollowingPatternMatchClause range when Range.equals range m -> os.Append(FSComp.SR.followingPatternMatchClauseHasWrongType(t1, t2)) |> ignore
+          | ContextInfo.PatternMatchGuard range when Range.equals range m -> os.Append(FSComp.SR.patternMatchGuardIsNotBool(t2)) |> ignore
          | _ -> os.Append(ConstraintSolverTypesNotInEqualityRelation2E().Format t1 t2) |> ignore
          if m.StartLine <> m2.StartLine then 
             os.Append(SeeAlsoE().Format (stringOfRange m)) |> ignore
@ -680,16 +681,16 @@ let OutputPhasedErrorR (os: StringBuilder) (err: PhasedDiagnostic) =
              && typeEquiv g t2 t2' ->
          let t1, t2, tpcs = NicePrint.minimalStringsOfTwoTypes denv t1 t2
          match contextInfo with
-          | ContextInfo.IfExpression range when range = m -> os.Append(FSComp.SR.ifExpression(t1, t2)) |> ignore
-          | ContextInfo.CollectionElement (isArray, range) when range = m -> 
+          | ContextInfo.IfExpression range when Range.equals range m -> os.Append(FSComp.SR.ifExpression(t1, t2)) |> ignore
+          | ContextInfo.CollectionElement (isArray, range) when Range.equals range m -> 
            if isArray then
                os.Append(FSComp.SR.arrayElementHasWrongType(t1, t2)) |> ignore
            else
                os.Append(FSComp.SR.listElementHasWrongType(t1, t2)) |> ignore
-          | ContextInfo.OmittedElseBranch range when range = m -> os.Append(FSComp.SR.missingElseBranch(t2)) |> ignore
-          | ContextInfo.ElseBranchResult range when range = m -> os.Append(FSComp.SR.elseBranchHasWrongType(t1, t2)) |> ignore
-          | ContextInfo.FollowingPatternMatchClause range when range = m -> os.Append(FSComp.SR.followingPatternMatchClauseHasWrongType(t1, t2)) |> ignore
-          | ContextInfo.PatternMatchGuard range when range = m -> os.Append(FSComp.SR.patternMatchGuardIsNotBool(t2)) |> ignore
+          | ContextInfo.OmittedElseBranch range when Range.equals range m -> os.Append(FSComp.SR.missingElseBranch(t2)) |> ignore
+          | ContextInfo.ElseBranchResult range when Range.equals range m -> os.Append(FSComp.SR.elseBranchHasWrongType(t1, t2)) |> ignore
+          | ContextInfo.FollowingPatternMatchClause range when Range.equals range m -> os.Append(FSComp.SR.followingPatternMatchClauseHasWrongType(t1, t2)) |> ignore
+          | ContextInfo.PatternMatchGuard range when Range.equals range m -> os.Append(FSComp.SR.patternMatchGuardIsNotBool(t2)) |> ignore
          | ContextInfo.TupleInRecordFields ->
                os.Append(ErrorFromAddingTypeEquation1E().Format t2 t1 tpcs) |> ignore
                os.Append(System.Environment.NewLine + FSComp.SR.commaInsteadOfSemicolonInRecord()) |> ignore
@ -824,9 +825,10 @@ let OutputPhasedErrorR (os: StringBuilder) (err: PhasedDiagnostic) =

      | UndefinedName(_, k, id, suggestionsF) ->
          os.Append(k (DecompileOpName id.idText)) |> ignore
-          let filtered = ErrorResolutionHints.FilterPredictions id.idText suggestionsF
-          if List.isEmpty filtered |> not then
-              os.Append(ErrorResolutionHints.FormatPredictions DecompileOpName filtered) |> ignore
+          if suggestNames then
+              let filtered = ErrorResolutionHints.FilterPredictions suggestionsF id.idText 
+              if List.isEmpty filtered |> not then
+                  os.Append(ErrorResolutionHints.FormatPredictions DecompileOpName filtered) |> ignore
          

      | InternalUndefinedItemRef(f, smr, ccuName, s) ->  
@ -1364,9 +1366,10 @@ let OutputPhasedErrorR (os: StringBuilder) (err: PhasedDiagnostic) =

      | ErrorWithSuggestions ((_, s), _, idText, suggestionF) -> 
          os.Append(DecompileOpName s) |> ignore
-          let filtered = ErrorResolutionHints.FilterPredictions idText suggestionF
-          if List.isEmpty filtered |> not then
-              os.Append(ErrorResolutionHints.FormatPredictions DecompileOpName filtered) |> ignore
+          if suggestNames then
+              let filtered = ErrorResolutionHints.FilterPredictions suggestionF idText
+              if List.isEmpty filtered |> not then
+                  os.Append(ErrorResolutionHints.FormatPredictions DecompileOpName filtered) |> ignore

      | NumberedError ((_, s), _) -> os.Append(s) |> ignore

@ -1581,11 +1584,11 @@ let OutputPhasedErrorR (os: StringBuilder) (err: PhasedDiagnostic) =
    OutputExceptionR os (err.Exception)


-// remove any newlines and tabs 
-let OutputPhasedDiagnostic (os: System.Text.StringBuilder) (err: PhasedDiagnostic) (flattenErrors: bool) = 
+// remove any newlines and tabs
+let OutputPhasedDiagnostic (os: System.Text.StringBuilder) (err: PhasedDiagnostic) (flattenErrors: bool) (suggestNames: bool) =
    let buf = new System.Text.StringBuilder()

-    OutputPhasedErrorR buf err
+    OutputPhasedErrorR buf err suggestNames
    let s = if flattenErrors then ErrorLogger.NormalizeErrorString (buf.ToString()) else buf.ToString()
    
    os.Append(s) |> ignore
@ -1635,9 +1638,9 @@ type Diagnostic =
    | Long of bool * DiagnosticDetailedInfo

 /// returns sequence that contains Diagnostic for the given error + Diagnostic for all related errors
-let CollectDiagnostic (implicitIncludeDir, showFullPaths, flattenErrors, errorStyle, isError, err: PhasedDiagnostic) = 
-    let outputWhere (showFullPaths, errorStyle) m: DiagnosticLocation = 
-        if m = rangeStartup || m = rangeCmdArgs then 
+let CollectDiagnostic (implicitIncludeDir, showFullPaths, flattenErrors, errorStyle, isError, err: PhasedDiagnostic, suggestNames: bool) =
+    let outputWhere (showFullPaths, errorStyle) m: DiagnosticLocation =
+        if Range.equals m rangeStartup || Range.equals m rangeCmdArgs then
            { Range = m; TextRepresentation = ""; IsEmpty = true; File = "" }
        else
            let file = m.FileName
@ -1672,7 +1675,7 @@ let CollectDiagnostic (implicitIncludeDir, showFullPaths, flattenErrors, errorSt
                  | ErrorStyle.VSErrors -> 
                        // Show prefix only for real files. Otherwise, we just want a truncated error like:
                        //      parse error FS0031: blah blah
-                        if m<>range0 && m<>rangeStartup && m<>rangeCmdArgs then 
+                        if not (Range.equals m range0) && not (Range.equals m rangeStartup) && not (Range.equals m rangeCmdArgs) then
                            let file = file.Replace("/", "\\")
                            let m = mkRange m.FileName (mkPos m.StartLine (m.StartColumn + 1)) (mkPos m.EndLine (m.EndColumn + 1) )
                            sprintf "%s(%d,%d,%d,%d): " file m.StartLine m.StartColumn m.EndLine m.EndColumn, m, file
@ -1708,7 +1711,7 @@ let CollectDiagnostic (implicitIncludeDir, showFullPaths, flattenErrors, errorSt
            let canonical = OutputCanonicalInformation(err.Subcategory(), GetDiagnosticNumber mainError)
            let message = 
                let os = System.Text.StringBuilder()
-                OutputPhasedDiagnostic os mainError flattenErrors
+                OutputPhasedDiagnostic os mainError flattenErrors suggestNames
                os.ToString()
            
            let entry: DiagnosticDetailedInfo = { Location = where; Canonical = canonical; Message = message }
@ -1723,7 +1726,7 @@ let CollectDiagnostic (implicitIncludeDir, showFullPaths, flattenErrors, errorSt
                    let relCanonical = OutputCanonicalInformation(err.Subcategory(), GetDiagnosticNumber mainError) // Use main error for code
                    let relMessage = 
                        let os = System.Text.StringBuilder()
-                        OutputPhasedDiagnostic os err flattenErrors
+                        OutputPhasedDiagnostic os err flattenErrors suggestNames
                        os.ToString()

                    let entry: DiagnosticDetailedInfo = { Location = relWhere; Canonical = relCanonical; Message = relMessage}
@ -1731,7 +1734,7 @@ let CollectDiagnostic (implicitIncludeDir, showFullPaths, flattenErrors, errorSt

                | _ -> 
                    let os = System.Text.StringBuilder()
-                    OutputPhasedDiagnostic os err flattenErrors
+                    OutputPhasedDiagnostic os err flattenErrors suggestNames
                    errors.Add( Diagnostic.Short(isError, os.ToString()) )
        
            relatedErrors |> List.iter OutputRelatedError
@ -1752,7 +1755,8 @@ let CollectDiagnostic (implicitIncludeDir, showFullPaths, flattenErrors, errorSt
 /// prints error and related errors to the specified StringBuilder
 let rec OutputDiagnostic (implicitIncludeDir, showFullPaths, flattenErrors, errorStyle, isError) os (err: PhasedDiagnostic) = 
    
-    let errors = CollectDiagnostic (implicitIncludeDir, showFullPaths, flattenErrors, errorStyle, isError, err)
+    // 'true' for "suggestNames" is passed last here because we want to report suggestions in fsc.exe and fsi.exe, just not in regular IDE usage.
+    let errors = CollectDiagnostic (implicitIncludeDir, showFullPaths, flattenErrors, errorStyle, isError, err, true)
    for e in errors do
        Printf.bprintf os "\n"
        match e with
@ -1782,7 +1786,6 @@ let OutputDiagnosticContext prefix fileLineFn os err =

 let (++) x s = x @ [s]

-
 //----------------------------------------------------------------------------
 // General file name resolver
 //--------------------------------------------------------------------------
@ -2392,12 +2395,12 @@ type TcConfigBuilder =
    member tcConfigB.AddReferencedAssemblyByPath (m, path) = 
        if FileSystem.IsInvalidPathShim(path) then
            warning(Error(FSComp.SR.buildInvalidAssemblyName(path), m))
-        elif not (tcConfigB.referencedDLLs |> List.exists (fun ar2 -> m=ar2.Range && path=ar2.Text)) then // NOTE: We keep same paths if range is different.
+        elif not (tcConfigB.referencedDLLs |> List.exists (fun ar2 -> Range.equals m ar2.Range && path=ar2.Text)) then // NOTE: We keep same paths if range is different.
             let projectReference = tcConfigB.projectReferences |> List.tryPick (fun pr -> if pr.FileName = path then Some pr else None)
             tcConfigB.referencedDLLs <- tcConfigB.referencedDLLs ++ AssemblyReference(m, path, projectReference)
             
    member tcConfigB.RemoveReferencedAssemblyByPath (m, path) =
-        tcConfigB.referencedDLLs <- tcConfigB.referencedDLLs |> List.filter (fun ar-> ar.Range <> m || ar.Text <> path)
+        tcConfigB.referencedDLLs <- tcConfigB.referencedDLLs |> List.filter (fun ar -> not (Range.equals ar.Range m) || ar.Text <> path)
    
    static member SplitCommandLineResourceInfo (ri: string) =
        let p = ri.IndexOf ','
@ -2542,7 +2545,7 @@ type TcConfig private (data: TcConfigBuilder, validate: bool) =
                r, Some(filename)
            else   
                // If the file doesn't exist, let reference resolution logic report the error later...
-                defaultCoreLibraryReference, if r.Range =rangeStartup then Some(filename) else None
+                defaultCoreLibraryReference, if Range.equals r.Range rangeStartup then Some(filename) else None
        match data.referencedDLLs |> List.filter (fun assemblyReference -> assemblyReference.SimpleAssemblyNameIs libraryName) with
        | [r] -> nameOfDll r
        | [] -> 
@ -2899,7 +2902,13 @@ type TcConfig private (data: TcConfigBuilder, validate: bool) =
                // file is included in the search path. This should ideally already be one of the search paths, but
                // during some global checks it won't be. We append to the end of the search list so that this is the last
                // place that is checked.
-                if m <> range0 && m <> rangeStartup && m <> rangeCmdArgs && FileSystem.IsPathRootedShim m.FileName then
+                let isPoundRReference (r: range) =
+                    not (Range.equals r range0) &&
+                    not (Range.equals r rangeStartup) &&
+                    not (Range.equals r rangeCmdArgs) &&
+                    FileSystem.IsPathRootedShim r.FileName
+
+                if isPoundRReference m then
                    tcConfig.GetSearchPathsForLibraryFiles() @ [Path.GetDirectoryName(m.FileName)]
                else    
                    tcConfig.GetSearchPathsForLibraryFiles()
@ -4840,7 +4849,7 @@ module private ScriptPreprocessClosure =
    open Internal.Utilities.Text.Lexing
    
    /// Represents an input to the closure finding process
-    type ClosureSource = ClosureSource of filename: string * referenceRange: range * sourceText: string * parseRequired: bool 
+    type ClosureSource = ClosureSource of filename: string * referenceRange: range * sourceText: ISourceText * parseRequired: bool 
        
    /// Represents an output of the closure finding process
    type ClosureFile = ClosureFile of string * range * ParsedInput option * (PhasedDiagnostic * bool) list * (PhasedDiagnostic * bool) list * (string * range) list // filename, range, errors, warnings, nowarns
@ -4856,8 +4865,8 @@ module private ScriptPreprocessClosure =
    
    /// Parse a script from source.
    let ParseScriptText
-           (filename: string, source: string, tcConfig: TcConfig, codeContext, 
-            lexResourceManager: Lexhelp.LexResourceManager, errorLogger: ErrorLogger) =    
+           (filename: string, sourceText: ISourceText, tcConfig: TcConfig, codeContext,
+            lexResourceManager: Lexhelp.LexResourceManager, errorLogger: ErrorLogger) =

        // fsc.exe -- COMPILED\!INTERACTIVE
        // fsi.exe -- !COMPILED\INTERACTIVE
@ -4869,7 +4878,7 @@ module private ScriptPreprocessClosure =
            | CodeContext.CompilationAndEvaluation -> ["INTERACTIVE"]
            | CodeContext.Compilation -> ["COMPILED"]
            | CodeContext.Editing -> "EDITING" :: (if IsScript filename then ["INTERACTIVE"] else ["COMPILED"])
-        let lexbuf = UnicodeLexing.StringAsLexbuf source 
+        let lexbuf = UnicodeLexing.SourceTextAsLexbuf(sourceText) 
        
        let isLastCompiland = (IsScript filename), tcConfig.target.IsExe        // The root compiland is last in the list of compilands.
        ParseOneInputLexbuf (tcConfig, lexResourceManager, defines, lexbuf, filename, isLastCompiland, errorLogger) 
@ -4920,7 +4929,7 @@ module private ScriptPreprocessClosure =
                | None -> new StreamReader(stream, true)
                | Some (n: int) -> new StreamReader(stream, Encoding.GetEncoding(n)) 
            let source = reader.ReadToEnd()
-            [ClosureSource(filename, m, source, parseRequired)]
+            [ClosureSource(filename, m, SourceText.ofString source, parseRequired)]
        with e -> 
            errorRecovery e m 
            []
@ -4953,7 +4962,7 @@ module private ScriptPreprocessClosure =
        let tcConfig = ref tcConfig
        
        let observedSources = Observed()
-        let rec loop (ClosureSource(filename, m, source, parseRequired)) = 
+        let rec loop (ClosureSource(filename, m, sourceText, parseRequired)) = 
          [     if not (observedSources.HaveSeen(filename)) then
                    observedSources.SetSeen(filename)
                    //printfn "visiting %s" filename
@ -4961,7 +4970,7 @@ module private ScriptPreprocessClosure =
                        let parseResult, parseDiagnostics =
                            let errorLogger = CapturingErrorLogger("FindClosureParse")                    
                            use _unwindEL = PushErrorLoggerPhaseUntilUnwind (fun _ -> errorLogger)
-                            let result = ParseScriptText (filename, source, !tcConfig, codeContext, lexResourceManager, errorLogger) 
+                            let result = ParseScriptText (filename, sourceText, !tcConfig, codeContext, lexResourceManager, errorLogger) 
                            result, errorLogger.Diagnostics

                        match parseResult with 
@ -5055,7 +5064,7 @@ module private ScriptPreprocessClosure =
            match GetRangeOfDiagnostic exn with
            | Some m -> 
                // Return true if the error was *not* from a #load-ed file.
-                let isArgParameterWhileNotEditing = (codeContext <> CodeContext.Editing) && (m = range0 || m = rangeStartup || m = rangeCmdArgs)
+                let isArgParameterWhileNotEditing = (codeContext <> CodeContext.Editing) && (Range.equals m range0 || Range.equals m rangeStartup || Range.equals m rangeCmdArgs)
                let isThisFileName = (0 = String.Compare(rootFilename, m.FileName, StringComparison.OrdinalIgnoreCase))
                isArgParameterWhileNotEditing || isThisFileName
            | None -> true
@ -5078,13 +5087,12 @@ module private ScriptPreprocessClosure =

    /// Given source text, find the full load closure. Used from service.fs, when editing a script file
    let GetFullClosureOfScriptText
-           (ctok, legacyReferenceResolver, defaultFSharpBinariesDir, 
-            filename, source, 
-            codeContext, useSimpleResolution, useFsiAuxLib, 
-            lexResourceManager: Lexhelp.LexResourceManager, 
-            applyCommmandLineArgs, assumeDotNetFramework, 
-            tryGetMetadataSnapshot, reduceMemoryUsage) = 
-
+           (ctok, legacyReferenceResolver, defaultFSharpBinariesDir,
+            filename, sourceText,
+            codeContext, useSimpleResolution, useFsiAuxLib,
+            lexResourceManager: Lexhelp.LexResourceManager,
+            applyCommmandLineArgs, assumeDotNetFramework,
+            tryGetMetadataSnapshot, reduceMemoryUsage) =
        // Resolve the basic references such as FSharp.Core.dll first, before processing any #I directives in the script
        //
        // This is tries to mimic the action of running the script in F# Interactive - the initial context for scripting is created
@ -5105,7 +5113,7 @@ module private ScriptPreprocessClosure =
                 codeContext, useSimpleResolution, useFsiAuxLib, Some references0, 
                 applyCommmandLineArgs, assumeDotNetFramework, tryGetMetadataSnapshot, reduceMemoryUsage)

-        let closureSources = [ClosureSource(filename, range0, source, true)]
+        let closureSources = [ClosureSource(filename, range0, sourceText, true)]
        let closureFiles, tcConfig = FindClosureFiles(closureSources, tcConfig, codeContext, lexResourceManager)
        GetLoadClosure(ctok, filename, closureFiles, tcConfig, codeContext)
        
@ -5124,23 +5132,26 @@ module private ScriptPreprocessClosure =

 type LoadClosure with
    /// Analyze a script text and find the closure of its references. 
+    /// Used from FCS, when editing a script file.  
+    //
+    /// A temporary TcConfig is created along the way, is why this routine takes so many arguments. We want to be sure to use exactly the
+    /// same arguments as the rest of the application.
    static member ComputeClosureOfScriptText
-                     (ctok, legacyReferenceResolver, defaultFSharpBinariesDir, 
-                      filename: string, source: string, codeContext, useSimpleResolution: bool, 
-                      useFsiAuxLib, lexResourceManager: Lexhelp.LexResourceManager, 
-                      applyCommmandLineArgs, assumeDotNetFramework, tryGetMetadataSnapshot, reduceMemoryUsage) = 
+                  (ctok, legacyReferenceResolver, defaultFSharpBinariesDir,
+                   filename: string, sourceText:ISourceText, codeContext, useSimpleResolution: bool,
+                   useFsiAuxLib, lexResourceManager: Lexhelp.LexResourceManager,
+                   applyCommmandLineArgs, assumeDotNetFramework, tryGetMetadataSnapshot, reduceMemoryUsage): LoadClosure =

        use unwindBuildPhase = PushThreadBuildPhaseUntilUnwind BuildPhase.Parse
        ScriptPreprocessClosure.GetFullClosureOfScriptText
-            (ctok, legacyReferenceResolver, defaultFSharpBinariesDir, filename, source, 
-             codeContext, useSimpleResolution, useFsiAuxLib, lexResourceManager, 
+            (ctok, legacyReferenceResolver, defaultFSharpBinariesDir, filename, sourceText,
+             codeContext, useSimpleResolution, useFsiAuxLib, lexResourceManager,
             applyCommmandLineArgs, assumeDotNetFramework, tryGetMetadataSnapshot, reduceMemoryUsage)

    /// Analyze a set of script files and find the closure of their references.
-    static member ComputeClosureOfScriptFiles 
-                     (ctok, tcConfig: TcConfig, files:(string*range) list, codeContext, 
-                      lexResourceManager: Lexhelp.LexResourceManager) = 
-
+    static member ComputeClosureOfScriptFiles
+                     (ctok, tcConfig: TcConfig, files:(string*range) list, codeContext,
+                      lexResourceManager: Lexhelp.LexResourceManager) =
        use unwindBuildPhase = PushThreadBuildPhaseUntilUnwind BuildPhase.Parse
        ScriptPreprocessClosure.GetFullClosureOfScriptFiles (ctok, tcConfig, files, codeContext, lexResourceManager)
        
@ -5444,4 +5455,4 @@ let TypeCheckClosedInputSet (ctok, checkForErrors, tcConfig, tcImports, tcGlobal

 // Existing public APIs delegate to newer implementations
 let GetFSharpCoreLibraryName () = getFSharpCoreLibraryName
-let DefaultReferencesForScriptsAndOutOfProjectSources assumeDotNetFramework = defaultReferencesForScriptsAndOutOfProjectSources assumeDotNetFramework
+let DefaultReferencesForScriptsAndOutOfProjectSources assumeDotNetFramework = defaultReferencesForScriptsAndOutOfProjectSources assumeDotNetFramework 
--- a/src/fsharp/CompileOps.fsi
+++ b/src/fsharp/CompileOps.fsi
@ -9,14 +9,15 @@ open System.Collections.Generic
 open FSharp.Compiler.AbstractIL
 open FSharp.Compiler.AbstractIL.IL
 open FSharp.Compiler.AbstractIL.ILBinaryReader
-open FSharp.Compiler.AbstractIL.Internal.Library 
-open FSharp.Compiler 
+open FSharp.Compiler.AbstractIL.Internal.Library
+open FSharp.Compiler
 open FSharp.Compiler.TypeChecker
 open FSharp.Compiler.Range
 open FSharp.Compiler.Ast
 open FSharp.Compiler.ErrorLogger
 open FSharp.Compiler.Tast
 open FSharp.Compiler.TcGlobals
+open FSharp.Compiler.Text
 open Microsoft.FSharp.Core.CompilerServices
 #if !NO_EXTENSIONTYPING
 open FSharp.Compiler.ExtensionTyping
@ -82,7 +83,7 @@ val GetDiagnosticNumber: PhasedDiagnostic -> int
 val SplitRelatedDiagnostics: PhasedDiagnostic -> PhasedDiagnostic * PhasedDiagnostic list

 /// Output an error to a buffer
-val OutputPhasedDiagnostic: StringBuilder -> PhasedDiagnostic -> flattenErrors: bool -> unit
+val OutputPhasedDiagnostic: StringBuilder -> PhasedDiagnostic -> flattenErrors: bool -> suggestNames: bool -> unit

 /// Output an error or warning to a buffer
 val OutputDiagnostic: implicitIncludeDir:string * showFullPaths: bool * flattenErrors: bool * errorStyle: ErrorStyle *  isError:bool -> StringBuilder -> PhasedDiagnostic -> unit
@ -119,7 +120,7 @@ type Diagnostic =
    | Long of bool * DiagnosticDetailedInfo

 /// Part of LegacyHostedCompilerForTesting
-val CollectDiagnostic: implicitIncludeDir:string * showFullPaths: bool * flattenErrors: bool * errorStyle: ErrorStyle *  warning:bool * PhasedDiagnostic -> seq<Diagnostic>
+val CollectDiagnostic: implicitIncludeDir:string * showFullPaths: bool * flattenErrors: bool * errorStyle: ErrorStyle *  warning:bool * PhasedDiagnostic * suggestNames: bool -> seq<Diagnostic>

 //----------------------------------------------------------------------------
 // Resolve assembly references 
@ -800,7 +801,7 @@ type LoadClosure =
    //
    /// A temporary TcConfig is created along the way, is why this routine takes so many arguments. We want to be sure to use exactly the
    /// same arguments as the rest of the application.
-    static member ComputeClosureOfScriptText: CompilationThreadToken * legacyReferenceResolver: ReferenceResolver.Resolver * defaultFSharpBinariesDir: string * filename: string * source: string * implicitDefines:CodeContext * useSimpleResolution: bool * useFsiAuxLib: bool * lexResourceManager: Lexhelp.LexResourceManager * applyCompilerOptions: (TcConfigBuilder -> unit) * assumeDotNetFramework: bool * tryGetMetadataSnapshot: ILReaderTryGetMetadataSnapshot * reduceMemoryUsage: ReduceMemoryFlag -> LoadClosure
+    static member ComputeClosureOfScriptText: CompilationThreadToken * legacyReferenceResolver: ReferenceResolver.Resolver * defaultFSharpBinariesDir: string * filename: string * sourceText: ISourceText * implicitDefines:CodeContext * useSimpleResolution: bool * useFsiAuxLib: bool * lexResourceManager: Lexhelp.LexResourceManager * applyCompilerOptions: (TcConfigBuilder -> unit) * assumeDotNetFramework: bool * tryGetMetadataSnapshot: ILReaderTryGetMetadataSnapshot * reduceMemoryUsage: ReduceMemoryFlag -> LoadClosure

    /// Analyze a set of script files and find the closure of their references. The resulting references are then added to the given TcConfig.
    /// Used from fsi.fs and fsc.fs, for #load and command line. 
--- a/src/fsharp/ConstraintSolver.fs
+++ b/src/fsharp/ConstraintSolver.fs
@ -1931,7 +1931,7 @@ and SolveTypeIsNonNullableValueType (csenv: ConstraintSolverEnv) ndeep m2 trace
        | _ ->
            let underlyingTy = stripTyEqnsAndMeasureEqns g ty
            if isStructTy g underlyingTy then
-                if tyconRefEq g g.system_Nullable_tcref (tcrefOfAppTy g underlyingTy) then
+                if isAppTy g underlyingTy && tyconRefEq g g.system_Nullable_tcref (tcrefOfAppTy g underlyingTy) then
                    return! ErrorD (ConstraintSolverError(FSComp.SR.csTypeParameterCannotBeNullable(), m, m))
            else
                return! ErrorD (ConstraintSolverError(FSComp.SR.csGenericConstructRequiresStructType(NicePrint.minimalStringOfType denv ty), m, m2))
--- a/src/fsharp/ErrorLogger.fs
+++ b/src/fsharp/ErrorLogger.fs
@ -125,7 +125,7 @@ let inline protectAssemblyExplorationNoReraise dflt1 dflt2 f  =

 // Attach a range if this is a range dual exception.
 let rec AttachRange m (exn:exn) = 
-    if m = range0 then exn
+    if Range.equals m range0 then exn
    else 
        match exn with
        // Strip TargetInvocationException wrappers
--- a/src/fsharp/ErrorResolutionHints.fs
+++ b/src/fsharp/ErrorResolutionHints.fs
@ -24,7 +24,7 @@ let IsInEditDistanceProximity idText suggestion =
    editDistance <= threshold

 /// Filters predictions based on edit distance to the given unknown identifier.
-let FilterPredictions (idText:string) (suggestionF:ErrorLogger.Suggestions) =    
+let FilterPredictions (suggestionF:ErrorLogger.Suggestions) (idText:string) =    
    let uppercaseText = idText.ToUpperInvariant()
    let allSuggestions = suggestionF()

--- a/src/fsharp/FSharp.Build/FSharp.Build.fsproj
+++ b/src/fsharp/FSharp.Build/FSharp.Build.fsproj
@ -4,7 +4,7 @@

  <PropertyGroup>
    <OutputType>Library</OutputType>
-    <TargetFrameworks>net46;netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>net472;netstandard2.0</TargetFrameworks>
    <TargetFrameworks Condition="'$(OS)' == 'Unix'">netstandard2.0</TargetFrameworks>
    <AssemblyName>FSharp.Build</AssemblyName>
    <NoWarn>$(NoWarn);45;55;62;75;1204</NoWarn>
@ -36,7 +36,7 @@
    <ProjectReference Include="$(MSBuildThisFileDirectory)..\FSharp.Core\FSharp.Core.fsproj" />
  </ItemGroup>

-  <ItemGroup Condition="'$(TargetFramework)' == 'net46'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'net472'">
    <PackageReference Include="Microsoft.VisualFSharp.Type.Providers.Redist" Version="$(MicrosoftVisualFSharpTypeProvidersRedistPackageVersion)" />
  </ItemGroup>

--- a/src/fsharp/FSharp.Build/Microsoft.FSharp.NetSdk.props
+++ b/src/fsharp/FSharp.Build/Microsoft.FSharp.NetSdk.props
@ -74,7 +74,7 @@ WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and

  <PropertyGroup>
    <DefaultValueTuplePackageVersion>4.4.0</DefaultValueTuplePackageVersion>
-    <DefaultFSharpCorePackageVersion>4.5.2</DefaultFSharpCorePackageVersion>
+    <DefaultFSharpCorePackageVersion>4.6.2</DefaultFSharpCorePackageVersion>
    <ValueTupleImplicitPackageVersion>$(DefaultValueTuplePackageVersion)</ValueTupleImplicitPackageVersion>
    <FSharpCoreImplicitPackageVersion>$(DefaultFSharpCorePackageVersion)</FSharpCoreImplicitPackageVersion>
  </PropertyGroup>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.cs.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.cs.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="cs" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">Parametr ToolPath není známý. Zadejte cestu k nástroji.</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.de.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.de.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="de" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">ToolPath unbekannt. Geben Sie den Pfad zum Tool an.</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.es.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.es.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="es" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">ToolPath se desconoce; especifique la ruta de acceso a la herramienta.</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.fr.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.fr.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="fr" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">ToolPath est inconnu, spécifiez le chemin de l'outil.</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.it.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.it.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="it" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">Il valore di ToolPath è sconosciuto. Specificare il percorso dello strumento.</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.ja.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.ja.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="ja" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">ToolPath が不明です。ツールンパスを指定します。</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.ko.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.ko.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="ko" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">ToolPath를 알 수 없습니다. 도구 경로를 지정하세요.</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.pl.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.pl.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="pl" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">Właściwość ToolPath jest nieznana. Określ ścieżkę do narzędzia.</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.pt-BR.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.pt-BR.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="pt-BR" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">ToolPath desconhecido. Especifique o caminho para a ferramenta.</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.ru.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.ru.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="ru" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">Путь к инструменту (ToolPath) неизвестен, укажите путь к инструменту.</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.tr.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.tr.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="tr" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">ToolPath bilinmiyor; aracın yolunu belirtin.</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.zh-Hans.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.zh-Hans.xlf
@ -4,7 +4,7 @@
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">ToolPath 未知；请指定工具的路径。</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Build/xlf/FSBuild.txt.zh-Hant.xlf
+++ b/src/fsharp/FSharp.Build/xlf/FSBuild.txt.zh-Hant.xlf
@ -1,10 +1,10 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="zh-Hant" original="../FSBuild.resx">
    <body>
      <trans-unit id="toolpathUnknown">
        <source>ToolPath is unknown; specify the path to the tool.</source>
-        <target state="needs translation">ToolPath is unknown; specify the path to the tool.</target>
+        <target state="translated">ToolPath 未知; 請指定工具的路徑。</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/FSharp.Compiler.Interactive.Settings/FSharp.Compiler.Interactive.Settings.fsproj
+++ b/src/fsharp/FSharp.Compiler.Interactive.Settings/FSharp.Compiler.Interactive.Settings.fsproj
@ -4,7 +4,7 @@

  <PropertyGroup>
    <OutputType>Library</OutputType>
-    <TargetFrameworks>net46;netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>net472;netstandard2.0</TargetFrameworks>
    <TargetFrameworks Condition="'$(OS)' == 'Unix'">netstandard2.0</TargetFrameworks>
    <AssemblyName>FSharp.Compiler.Interactive.Settings</AssemblyName>
    <NoWarn>$(NoWarn);45;55;62;75;1182;1204</NoWarn>
--- a/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
+++ b/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
@ -4,7 +4,7 @@

  <PropertyGroup>
    <OutputType>Library</OutputType>
-    <TargetFrameworks>net46;netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>net472;netstandard2.0</TargetFrameworks>
    <TargetFrameworks Condition="'$(OS)' == 'Unix'">netstandard2.0</TargetFrameworks>
    <AssemblyName>FSharp.Compiler.Private</AssemblyName>
    <NoWarn>$(NoWarn);45;55;62;75;1204</NoWarn>
@ -12,10 +12,17 @@
    <DefineConstants>$(DefineConstants);COMPILER</DefineConstants>
    <DefineConstants>$(DefineConstants);MSBUILD_AT_LEAST_15</DefineConstants>
    <OtherFlags>$(OtherFlags) --warnon:1182 --maxerrors:20 --extraoptimizationloops:1</OtherFlags>
-    <UseAssetTargetFallback>true</UseAssetTargetFallback>
    <Tailcalls>true</Tailcalls> <!-- .tail annotations always emitted for this binary, even in debug mode -->
  </PropertyGroup>

+  <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|net472|AnyCPU'">
+    <Tailcalls>true</Tailcalls>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|netstandard2.0|AnyCPU'">
+    <Tailcalls>true</Tailcalls>
+  </PropertyGroup>
+
  <Target Name="CopyToBuiltBin" BeforeTargets="BuiltProjectOutputGroup" AfterTargets="CoreCompile">
    <PropertyGroup>
      <BuildOutputGroupLocation>$(BaseOutputPath)\$(Configuration)\$(TargetFramework)</BuildOutputGroupLocation>
@ -27,7 +34,6 @@
      <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\Microsoft.Build.Tasks.Core.dll" />
      <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\System.Reflection.Metadata.dll" />
      <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\System.Collections.Immutable.dll" />
-      <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\System.ValueTuple.dll" />
    </ItemGroup>
  </Target>

@ -50,6 +56,7 @@
    <InternalsVisibleTo Include="HostedCompilerServer" />
    <InternalsVisibleTo Include="FSharp.Tests.FSharpSuite" />
    <InternalsVisibleTo Include="LanguageServiceProfiling" />
+    <InternalsVisibleTo Include="CompilerServiceBenchmarks" />
  </ItemGroup>

  <ItemGroup>
@ -622,6 +629,12 @@
    <Compile Include="..\service\service.fs">
      <Link>Service/service.fs</Link>
    </Compile>
+    <Compile Include="..\service\ServiceErrorResolutionHints.fsi">
+      <Link>Service/ServiceErrorResolutionHints.fsi</Link>
+    </Compile>
+    <Compile Include="..\service\ServiceErrorResolutionHints.fs">
+      <Link>Service/ServiceErrorResolutionHints.fs</Link>
+    </Compile>
    <Compile Include="..\service\ServiceInterfaceStubGenerator.fsi">
      <Link>Service/ServiceInterfaceStubGenerator.fsi</Link>
    </Compile>
@ -652,7 +665,7 @@
      <Link>InteractiveSession/fsi.fs</Link>
    </Compile>

-    <Compile Include="..\MSBuildReferenceResolver.fs"  Condition="'$(MonoPackaging)' != 'true'">
+    <Compile Include="..\MSBuildReferenceResolver.fs" Condition="'$(MonoPackaging)' != 'true'">
      <Link>Misc/MSBuildReferenceResolver.fs</Link>
    </Compile>
    <!-- an old API for testing the compiler and gathering diagnostics in-memory -->
@ -665,7 +678,7 @@
    <ProjectReference Include="$(MSBuildThisFileDirectory)..\FSharp.Core\FSharp.Core.fsproj" />
  </ItemGroup>

-  <ItemGroup Condition="'$(TargetFramework)' == 'net46'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'net472'">
    <Reference Include="ISymWrapper, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
    <PackageReference Include="Microsoft.Build" Version="$(MicrosoftBuildPackageVersion)" />
    <PackageReference Include="Microsoft.Build.Framework" Version="$(MicrosoftBuildPackageVersion)" />
@ -697,7 +710,6 @@
    <PackageReference Include="System.Threading.Tasks.Parallel" Version="$(SystemThreadingTasksParallelPackageVersion)" />
    <PackageReference Include="System.Threading.Thread" Version="$(SystemThreadingThreadPackageVersion)" />
    <PackageReference Include="System.Threading.ThreadPool" Version="$(SystemThreadingThreadPoolPackageVersion)" />
-    <PackageReference Include="System.ValueTuple" Version="$(SystemValueTuplePackageVersion)" />
  </ItemGroup>

 </Project>
--- a/src/fsharp/FSharp.Compiler.Server.Shared/FSharp.Compiler.Server.Shared.fsproj
+++ b/src/fsharp/FSharp.Compiler.Server.Shared/FSharp.Compiler.Server.Shared.fsproj
@ -3,8 +3,10 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net46</TargetFramework>
    <NGenBinary>true</NGenBinary>
+    <TargetFramework>net472</TargetFramework>
+    <AssemblyName>FSharp.Compiler.Server.Shared</AssemblyName>
+    <UseFSharpProductVersion>true</UseFSharpProductVersion>
  </PropertyGroup>

  <ItemGroup>
--- a/src/fsharp/FSharp.Core/xlf/FSCore.cs.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.cs.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="cs" original="../FSCore.resx">
    <body>
--- a/src/fsharp/FSharp.Core/xlf/FSCore.de.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.de.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="de" original="../FSCore.resx">
    <body>
--- a/src/fsharp/FSharp.Core/xlf/FSCore.es.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.es.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="es" original="../FSCore.resx">
    <body>
--- a/src/fsharp/FSharp.Core/xlf/FSCore.fr.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.fr.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="fr" original="../FSCore.resx">
    <body>
--- a/src/fsharp/FSharp.Core/xlf/FSCore.it.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.it.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="it" original="../FSCore.resx">
    <body>
--- a/src/fsharp/FSharp.Core/xlf/FSCore.ja.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.ja.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="ja" original="../FSCore.resx">
    <body>
@ -204,7 +204,7 @@
      </trans-unit>
      <trans-unit id="notAPermutation">
        <source>The function did not compute a permutation.</source>
-        <target state="translated">関数は順列を計算しませんでした。</target>
+        <target state="translated">関数は順列をコンピューティングしませんでした。</target>
        <note />
      </trans-unit>
      <trans-unit id="notARecordType">
--- a/src/fsharp/FSharp.Core/xlf/FSCore.ko.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.ko.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="ko" original="../FSCore.resx">
    <body>
@ -314,7 +314,7 @@
      </trans-unit>
      <trans-unit id="QtmmExpectedFunction">
        <source>Type mismatch when building '{0}': expected function type in function application or let binding. Expected '{1}', but received type '{2}'.</source>
-        <target state="translated">{0}'을(를) 작성하는 동안 형식 불일치 문제가 발생했습니다. 함수 응용 프로그램 또는 let 바인딩에 함수 형식이 필요합니다. '{1}'이(가) 필요한데 '{2}' 형식을 수신했습니다.</target>
+        <target state="translated">'{0}'을(를) 작성하는 동안 형식 불일치 문제가 발생했습니다. 함수 애플리케이션 또는 let 바인딩에 함수 형식이 필요합니다. '{1}'이(가) 필요한데 '{2}' 형식을 수신했습니다.</target>
        <note />
      </trans-unit>
      <trans-unit id="QtmmExprNotMatchTuple">
--- a/src/fsharp/FSharp.Core/xlf/FSCore.pl.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.pl.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="pl" original="../FSCore.resx">
    <body>
--- a/src/fsharp/FSharp.Core/xlf/FSCore.pt-BR.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.pt-BR.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="pt-BR" original="../FSCore.resx">
    <body>
--- a/src/fsharp/FSharp.Core/xlf/FSCore.ru.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.ru.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="ru" original="../FSCore.resx">
    <body>
@ -514,7 +514,7 @@
      </trans-unit>
      <trans-unit id="QunionNeedsDiffNumArgs">
        <source>F# union type requires different number of arguments</source>
-        <target state="translated">К# типу объединения требуется другое количество аргументов</target>
+        <target state="translated">Типу объединения F# требуется другое количество аргументов</target>
        <note />
      </trans-unit>
      <trans-unit id="QwritingGetOnly">
--- a/src/fsharp/FSharp.Core/xlf/FSCore.tr.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.tr.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="tr" original="../FSCore.resx">
    <body>
--- a/src/fsharp/FSharp.Core/xlf/FSCore.zh-Hant.xlf
+++ b/src/fsharp/FSharp.Core/xlf/FSCore.zh-Hant.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="zh-Hant" original="../FSCore.resx">
    <body>
--- a/src/fsharp/NameResolution.fs
+++ b/src/fsharp/NameResolution.fs
@ -23,6 +23,7 @@ open FSharp.Compiler.AccessibilityLogic
 open FSharp.Compiler.AttributeChecking
 open FSharp.Compiler.InfoReader
 open FSharp.Compiler.PrettyNaming
+open FSharp.Compiler.Text
 open System.Collections.Generic

 #if !NO_EXTENSIONTYPING
@ -897,7 +898,7 @@ let AddResults res1 res2 =
    | Exception _, Result l -> Result l
    | Result x, Exception _ -> Result x
    // If we have error messages for the same symbol, then we can merge suggestions.
-    | Exception (UndefinedName(n1, f, id1, suggestions1)), Exception (UndefinedName(n2, _, id2, suggestions2)) when n1 = n2 && id1.idText = id2.idText && id1.idRange = id2.idRange ->
+    | Exception (UndefinedName(n1, f, id1, suggestions1)), Exception (UndefinedName(n2, _, id2, suggestions2)) when n1 = n2 && id1.idText = id2.idText && Range.equals id1.idRange id2.idRange ->
        let suggestions = HashSet(suggestions1())
        suggestions.UnionWith(suggestions2())
        Exception(UndefinedName(n1, f, id1, fun () -> suggestions))
@ -1251,7 +1252,7 @@ type OpenDeclaration =
          IsOwnNamespace = isOwnNamespace }

 type FormatStringCheckContext =
-    { Source: string
+    { SourceText: ISourceText
      LineStartPositions: int[] }

 /// An abstract type for reporting the results of name resolution and type checking.
@ -1261,7 +1262,7 @@ type ITypecheckResultsSink =
    abstract NotifyNameResolution: pos * Item * Item * TyparInst * ItemOccurence * Tastops.DisplayEnv * NameResolutionEnv * AccessorDomain * range * bool -> unit
    abstract NotifyFormatSpecifierLocation: range * int -> unit
    abstract NotifyOpenDeclaration: OpenDeclaration -> unit
-    abstract CurrentSource: string option
+    abstract CurrentSourceText: ISourceText option
    abstract FormatStringCheckContext: FormatStringCheckContext option

 let (|ValRefOfProp|_|) (pi: PropInfo) = pi.ArbitraryValRef
@ -1353,8 +1354,10 @@ let tyconRefDefnEq g (eref1: EntityRef) (eref2: EntityRef) =
    tyconRefEq g eref1 eref2 ||

    // Signature items considered equal to implementation items
-    eref1.DefinitionRange <> Range.rangeStartup && eref1.DefinitionRange <> Range.range0 && eref1.DefinitionRange <> Range.rangeCmdArgs &&
-    (eref1.DefinitionRange = eref2.DefinitionRange || eref1.SigRange = eref2.SigRange) &&
+    not (Range.equals eref1.DefinitionRange Range.rangeStartup) &&
+    not (Range.equals eref1.DefinitionRange Range.range0) &&
+    not (Range.equals eref1.DefinitionRange Range.rangeCmdArgs) &&
+    (Range.equals eref1.DefinitionRange eref2.DefinitionRange || Range.equals eref1.SigRange eref2.SigRange) &&
    eref1.LogicalName = eref2.LogicalName

 let valRefDefnHash (_g: TcGlobals) (vref1: ValRef) =
@ -1364,8 +1367,10 @@ let valRefDefnEq g (vref1: ValRef) (vref2: ValRef) =
    valRefEq g vref1 vref2 ||

    // Signature items considered equal to implementation items
-    vref1.DefinitionRange <> Range.rangeStartup && vref1.DefinitionRange <> Range.range0 && vref1.DefinitionRange <> Range.rangeCmdArgs &&
-    (vref1.DefinitionRange = vref2.DefinitionRange || vref1.SigRange = vref2.SigRange) &&
+    not (Range.equals vref1.DefinitionRange Range.rangeStartup) &&
+    not (Range.equals vref1.DefinitionRange Range.range0) &&
+    not (Range.equals vref1.DefinitionRange Range.rangeCmdArgs) &&
+    (Range.equals vref1.DefinitionRange vref2.DefinitionRange || Range.equals vref1.SigRange vref2.SigRange) &&
    vref1.LogicalName = vref2.LogicalName

 let unionCaseRefDefnEq g (uc1: UnionCaseRef) (uc2: UnionCaseRef) =
@ -1384,7 +1389,7 @@ let ItemsAreEffectivelyEqual g orig other =
         | TType_var tp1, TType_var tp2 ->
            not tp1.IsCompilerGenerated && not tp1.IsFromError &&
            not tp2.IsCompilerGenerated && not tp2.IsFromError &&
-            tp1.Range = tp2.Range
+            Range.equals tp1.Range tp2.Range
         | AbbrevOrAppTy tcref1, AbbrevOrAppTy tcref2 ->
            tyconRefDefnEq g tcref1 tcref2
         | _ -> false)
@ -1393,7 +1398,7 @@ let ItemsAreEffectivelyEqual g orig other =
        valRefDefnEq g vref1 vref2

    | ActivePatternCaseUse (range1, range1i, idx1), ActivePatternCaseUse (range2, range2i, idx2) ->
-        (idx1 = idx2) && (range1 = range2 || range1i = range2i)
+        (idx1 = idx2) && (Range.equals range1 range2 || Range.equals range1i range2i)

    | MethodUse minfo1, MethodUse minfo2 ->
        MethInfo.MethInfosUseIdenticalDefinitions minfo1 minfo2 ||
@ -1410,10 +1415,10 @@ let ItemsAreEffectivelyEqual g orig other =
        | _ -> false

    | Item.ArgName (id1, _, _), Item.ArgName (id2, _, _) ->
-        (id1.idText = id2.idText && id1.idRange = id2.idRange)
+        (id1.idText = id2.idText && Range.equals id1.idRange id2.idRange)

    | (Item.ArgName (id, _, _), ValUse vref) | (ValUse vref, Item.ArgName (id, _, _)) ->
-        ((id.idRange = vref.DefinitionRange || id.idRange = vref.SigRange) && id.idText = vref.DisplayName)
+        ((Range.equals id.idRange vref.DefinitionRange || Range.equals id.idRange vref.SigRange) && id.idText = vref.DisplayName)

    | Item.AnonRecdField(anon1, _, i1, _), Item.AnonRecdField(anon2, _, i2, _) -> Tastops.anonInfoEquiv anon1 anon2 && i1 = i2

@ -1520,7 +1525,7 @@ type TcSymbolUses(g, capturedNameResolutions: ResizeArray<CapturedNameResolution
    member this.GetFormatSpecifierLocationsAndArity() = formatSpecifierLocations

 /// An accumulator for the results being emitted into the tcSink.
-type TcResultsSinkImpl(g, ?source: string) =
+type TcResultsSinkImpl(g, ?sourceText: ISourceText) =
    let capturedEnvs = ResizeArray<_>()
    let capturedExprTypings = ResizeArray<_>()
    let capturedNameResolutions = ResizeArray<_>()
@ -1536,7 +1541,7 @@ type TcResultsSinkImpl(g, ?source: string) =
        new System.Collections.Generic.HashSet<range * Item>
            ( { new IEqualityComparer<range * Item> with
                    member __.GetHashCode ((m, _)) = hash m
-                    member __.Equals ((m1, item1), (m2, item2)) = m1 = m2 && ItemsAreEffectivelyEqual g item1 item2 } )
+                    member __.Equals ((m1, item1), (m2, item2)) = Range.equals m1 m2 && ItemsAreEffectivelyEqual g item1 item2 } )

    let capturedMethodGroupResolutions = ResizeArray<_>()
    let capturedOpenDeclarations = ResizeArray<OpenDeclaration>()
@ -1544,18 +1549,18 @@ type TcResultsSinkImpl(g, ?source: string) =

    let formatStringCheckContext =
        lazy
-            source |> Option.map (fun source ->
+            sourceText |> Option.map (fun sourceText ->
                let positions =
                    [|
                        yield 0
-                        for i in 1..source.Length do
-                            let c = source.[i-1]
-                            if c = '\r' && i < source.Length && source.[i] = '\n' then ()
+                        for i in 1..sourceText.Length do
+                            let c = sourceText.[i-1]
+                            if c = '\r' && i < sourceText.Length && sourceText.[i] = '\n' then ()
                            elif c = '\r' then yield i
                            elif c = '\n' then yield i
-                        yield source.Length
+                        yield sourceText.Length
                    |]
-                { Source = source
+                { SourceText = sourceText
                  LineStartPositions = positions })

    member this.GetResolutions() =
@ -1581,9 +1586,9 @@ type TcResultsSinkImpl(g, ?source: string) =
            // results in duplication of textual variables. So we ensure we never record two name resolutions
            // for the same identifier at the same location.
            if allowedRange m then
-                if replace then
-                    capturedNameResolutions.RemoveAll(fun cnr -> cnr.Range = m) |> ignore
-                    capturedMethodGroupResolutions.RemoveAll(fun cnr -> cnr.Range = m) |> ignore
+                if replace then 
+                    capturedNameResolutions.RemoveAll(fun cnr -> Range.equals cnr.Range m) |> ignore
+                    capturedMethodGroupResolutions.RemoveAll(fun cnr -> Range.equals cnr.Range m) |> ignore
                else
                    let alreadyDone =
                        match item with
@ -1610,7 +1615,7 @@ type TcResultsSinkImpl(g, ?source: string) =
        member sink.NotifyOpenDeclaration(openDeclaration) =
            capturedOpenDeclarations.Add(openDeclaration)

-        member sink.CurrentSource = source
+        member sink.CurrentSourceText = sourceText

        member sink.FormatStringCheckContext = formatStringCheckContext.Value

@ -1847,7 +1852,7 @@ let rec ResolveLongIndentAsModuleOrNamespace sink atMostOne amap m first fullyQu
        let mutable moduleNotFoundErrorCache = None
        let moduleNotFound (modref: ModuleOrNamespaceRef) (mty: ModuleOrNamespaceType) (id: Ident) depth =
            match moduleNotFoundErrorCache with
-            | Some (oldId, error) when oldId = id.idRange -> error
+            | Some (oldId, error) when Range.equals oldId id.idRange -> error
            | _ ->
                let suggestNames() =
                    mty.ModulesAndNamespacesByDemangledName
@ -2607,7 +2612,7 @@ let rec ResolveExprLongIdentPrim sink (ncenv: NameResolver) first fullyQualified
                          } |> HashSet

                      match innerSearch with
-                      | Exception (UndefinedName(0, _, id1, suggestionsF)) when id.idRange = id1.idRange ->
+                      | Exception (UndefinedName(0, _, id1, suggestionsF)) when Range.equals id.idRange id1.idRange ->
                            let mergeSuggestions() =
                                let res = suggestEverythingInScope()
                                res.UnionWith(suggestionsF())
@ -3295,7 +3300,7 @@ let ResolveLongIdentAsExprAndComputeRange (sink: TcResultsSink) (ncenv: NameReso
        match lid with
        | [] | [_] -> false
        | head :: ids ->
-            ids |> List.forall (fun id -> id.idRange = head.idRange)
+            ids |> List.forall (fun id -> Range.equals id.idRange head.idRange)

    let callSink (refinedItem, tpinst) =
        if not isFakeIdents then
--- a/src/fsharp/NameResolution.fsi
+++ b/src/fsharp/NameResolution.fsi
@ -2,7 +2,7 @@

 module internal FSharp.Compiler.NameResolution

-open FSharp.Compiler 
+open FSharp.Compiler
 open FSharp.Compiler.AccessibilityLogic
 open FSharp.Compiler.Ast
 open FSharp.Compiler.Infos
@ -14,6 +14,7 @@ open FSharp.Compiler.Tastops
 open FSharp.Compiler.TcGlobals
 open FSharp.Compiler.AbstractIL.Internal.Library
 open FSharp.Compiler.PrettyNaming
+open FSharp.Compiler.Text

 /// A NameResolver is a context for name resolution. It primarily holds an InfoReader.
 type NameResolver =
@ -347,7 +348,7 @@ type internal OpenDeclaration =
 /// Source text and an array of line end positions, used for format string parsing
 type FormatStringCheckContext =
    { /// Source text
-      Source: string
+      SourceText: ISourceText
      /// Array of line start positions
      LineStartPositions: int[] }

@ -370,7 +371,7 @@ type ITypecheckResultsSink =
    abstract NotifyOpenDeclaration : OpenDeclaration -> unit

    /// Get the current source
-    abstract CurrentSource : string option
+    abstract CurrentSourceText : ISourceText option

    /// Cached line-end normalized source text and an array of line end positions, used for format string parsing
    abstract FormatStringCheckContext : FormatStringCheckContext option
@ -379,7 +380,7 @@ type ITypecheckResultsSink =
 type internal TcResultsSinkImpl =

    /// Create a TcResultsSinkImpl
-    new : tcGlobals : TcGlobals * ?source:string -> TcResultsSinkImpl
+    new : tcGlobals : TcGlobals * ?sourceText: ISourceText -> TcResultsSinkImpl

    /// Get all the resolutions reported to the sink
    member GetResolutions : unit -> TcResolutions
--- a/src/fsharp/Optimizer.fs
+++ b/src/fsharp/Optimizer.fs
@ -1808,16 +1808,23 @@ let TryDetectQueryQuoteAndRun cenv (expr: Expr) =
    | _ -> 
        //printfn "Not eliminating because no Run found"
        None
-                
-let IsSystemStringConcatOverload (methRef: ILMethodRef) =
-    methRef.Name = "Concat" && methRef.DeclaringTypeRef.FullName = "System.String" && 
-    methRef.ReturnType.BasicQualifiedName = "System.String" &&
-    methRef.ArgTypes |> List.forall(fun ilty -> ilty.BasicQualifiedName = "System.String")

-let IsSystemStringConcatArray (methRef: ILMethodRef) =
-    methRef.Name = "Concat" && methRef.DeclaringTypeRef.FullName = "System.String" && 
-    methRef.ReturnType.BasicQualifiedName = "System.String" &&
-    methRef.ArgTypes.Length = 1 && methRef.ArgTypes.Head.BasicQualifiedName = "System.String[]"
+let IsILMethodRefDeclaringTypeSystemString (ilg: ILGlobals) (mref: ILMethodRef) =
+    mref.DeclaringTypeRef.Scope.IsAssemblyRef &&
+    mref.DeclaringTypeRef.Scope.AssemblyRef.Name = ilg.typ_String.TypeRef.Scope.AssemblyRef.Name &&
+    mref.DeclaringTypeRef.BasicQualifiedName = ilg.typ_String.BasicQualifiedName
+                
+let IsILMethodRefSystemStringConcatOverload (ilg: ILGlobals) (mref: ILMethodRef) =
+    IsILMethodRefDeclaringTypeSystemString ilg mref &&
+    mref.Name = "Concat" &&
+    mref.ReturnType.BasicQualifiedName = ilg.typ_String.BasicQualifiedName &&
+    mref.ArgCount >= 2 && mref.ArgCount <= 4 && mref.ArgTypes |> List.forall(fun ilty -> ilty.BasicQualifiedName = ilg.typ_String.BasicQualifiedName)
+
+let IsILMethodRefSystemStringConcatArray (ilg: ILGlobals) (mref: ILMethodRef) =
+    IsILMethodRefDeclaringTypeSystemString ilg mref &&
+    mref.Name = "Concat" &&
+    mref.ReturnType.BasicQualifiedName = ilg.typ_String.BasicQualifiedName &&
+    mref.ArgCount = 1 && mref.ArgTypes.Head.BasicQualifiedName = "System.String[]"
    
 /// Optimize/analyze an expression
 let rec OptimizeExpr cenv (env: IncrementalOptimizationEnv) expr =
@ -1944,10 +1951,10 @@ and OptimizeInterfaceImpl cenv env baseValOpt (ty, overrides) =
 and MakeOptimizedSystemStringConcatCall cenv env m args =
    let rec optimizeArg argExpr accArgs =
        match argExpr, accArgs with
-        | Expr.Op(TOp.ILCall(_, _, _, _, _, _, _, methRef, _, _, _), _, [ Expr.Op(TOp.Array, _, args, _) ], _), _ when IsSystemStringConcatArray methRef ->
+        | Expr.Op(TOp.ILCall(_, _, _, _, _, _, _, methRef, _, _, _), _, [ Expr.Op(TOp.Array, _, args, _) ], _), _ when IsILMethodRefSystemStringConcatArray cenv.g.ilg methRef ->
            optimizeArgs args accArgs

-        | Expr.Op(TOp.ILCall(_, _, _, _, _, _, _, methRef, _, _, _), _, args, _), _ when IsSystemStringConcatOverload methRef ->
+        | Expr.Op(TOp.ILCall(_, _, _, _, _, _, _, mref, _, _, _), _, args, _), _ when IsILMethodRefSystemStringConcatOverload cenv.g.ilg mref ->
            optimizeArgs args accArgs

        // Optimize string constants, e.g. "1" + "2" will turn into "12"
@ -1977,7 +1984,7 @@ and MakeOptimizedSystemStringConcatCall cenv env m args =
            mkStaticCall_String_Concat_Array cenv.g m arg

    match expr with
-    | Expr.Op(TOp.ILCall(_, _, _, _, _, _, _, methRef, _, _, _) as op, tyargs, args, m) when IsSystemStringConcatOverload methRef || IsSystemStringConcatArray methRef ->
+    | Expr.Op(TOp.ILCall(_, _, _, _, _, _, _, methRef, _, _, _) as op, tyargs, args, m) when IsILMethodRefSystemStringConcatOverload cenv.g.ilg methRef || IsILMethodRefSystemStringConcatArray cenv.g.ilg methRef ->
        OptimizeExprOpReductions cenv env (op, tyargs, args, m)
    | _ ->
        OptimizeExpr cenv env expr
@ -2046,9 +2053,9 @@ and OptimizeExprOp cenv env (op, tyargs, args, m) =
    | TOp.ILAsm([], [ty]), _, [a] when typeEquiv cenv.g (tyOfExpr cenv.g a) ty -> OptimizeExpr cenv env a

    // Optimize calls when concatenating strings, e.g. "1" + "2" + "3" + "4" .. etc.
-    | TOp.ILCall(_, _, _, _, _, _, _, methRef, _, _, _), _, [ Expr.Op(TOp.Array, _, args, _) ] when IsSystemStringConcatArray methRef ->
+    | TOp.ILCall(_, _, _, _, _, _, _, mref, _, _, _), _, [ Expr.Op(TOp.Array, _, args, _) ] when IsILMethodRefSystemStringConcatArray cenv.g.ilg mref ->
        MakeOptimizedSystemStringConcatCall cenv env m args
-    | TOp.ILCall(_, _, _, _, _, _, _, methRef, _, _, _), _, args when IsSystemStringConcatOverload methRef ->
+    | TOp.ILCall(_, _, _, _, _, _, _, mref, _, _, _), _, args when IsILMethodRefSystemStringConcatOverload cenv.g.ilg mref ->
        MakeOptimizedSystemStringConcatCall cenv env m args

    | _ -> 
--- a/src/fsharp/PatternMatchCompilation.fs
+++ b/src/fsharp/PatternMatchCompilation.fs
@ -1350,7 +1350,7 @@ let rec CompilePattern  g denv amap exprm matchm warnOnUnused actionOnFailure (o
            // If the remainder of the match boiled away to nothing interesting.
            // We measure this simply by seeing if the range of the resulting expression is identical to matchm.
            let spTarget =
-                if expr.Range = matchm then SuppressSequencePointAtTarget
+                if Range.equals expr.Range matchm then SuppressSequencePointAtTarget
                else SequencePointAtTarget

            // Make the clause that represents the remaining cases of the pattern match
--- a/src/fsharp/TastOps.fs
+++ b/src/fsharp/TastOps.fs
@ -1775,7 +1775,8 @@ let isRefTy g ty =
        isFunTy g ty || 
        isReprHiddenTy g ty || 
        isFSharpObjModelRefTy g ty || 
-        isUnitTy g ty
+        isUnitTy g ty ||
+        (isAnonRecdTy g ty && not (isStructAnonRecdTy g ty))
    )

 // ECMA C# LANGUAGE SPECIFICATION, 27.2
--- a/src/fsharp/TastPickle.fs
+++ b/src/fsharp/TastPickle.fs
@ -122,6 +122,7 @@ type WriterState =
    onlerefs: Table<int * int[]>
    osimpletys: Table<int>
    oglobals : TcGlobals
+    mutable isStructThisArgPos : bool
    ofile : string
    /// Indicates if we are using in-memory format, where we store XML docs as well
    oInMem : bool
@ -778,7 +779,8 @@ let pickleObjWithDanglingCcus inMem file g scope p x =
        osimpletys=Table<_>.Create "osimpletys"
        oglobals=g
        ofile=file
-        oInMem=inMem }
+        oInMem=inMem
+        isStructThisArgPos = false}
    p x st1
    let sizes =
      st1.oentities.Size,
@ -802,7 +804,8 @@ let pickleObjWithDanglingCcus inMem file g scope p x =
       osimpletys=Table<_>.Create "osimpletys (fake)"
       oglobals=g
       ofile=file
-       oInMem=inMem }
+       oInMem=inMem
+       isStructThisArgPos = false }
    p_array p_encoded_ccuref ccuNameTab.AsArray st2
    // Add a 4th integer indicated by a negative 1st integer
    let z1 = if nanoninfos > 0 then  -ntycons-1 else ntycons
--- a/src/fsharp/TypeChecker.fs
+++ b/src/fsharp/TypeChecker.fs
@ -671,22 +671,22 @@ let ShrinkContext env oldRange newRange =
    | ContextInfo.SequenceExpression _ ->
        env
    | ContextInfo.CollectionElement (b,m) ->
-        if m <> oldRange then env else
+        if not (Range.equals m oldRange) then env else
        { env with eContextInfo = ContextInfo.CollectionElement(b,newRange) }
    | ContextInfo.FollowingPatternMatchClause m -> 
-        if m <> oldRange then env else
+        if not (Range.equals m oldRange) then env else
        { env with eContextInfo = ContextInfo.FollowingPatternMatchClause newRange }
    | ContextInfo.PatternMatchGuard m -> 
-        if m <> oldRange then env else
+        if not (Range.equals m oldRange) then env else
        { env with eContextInfo = ContextInfo.PatternMatchGuard newRange }
    | ContextInfo.IfExpression m -> 
-        if m <> oldRange then env else
+        if not (Range.equals m oldRange) then env else
        { env with eContextInfo = ContextInfo.IfExpression newRange }
    | ContextInfo.OmittedElseBranch m -> 
-        if m <> oldRange then env else
+        if not (Range.equals m oldRange) then env else
        { env with eContextInfo = ContextInfo.OmittedElseBranch newRange }
    | ContextInfo.ElseBranchResult m -> 
-        if m <> oldRange then env else
+        if not (Range.equals m oldRange) then env else
        { env with eContextInfo = ContextInfo.ElseBranchResult newRange }

 /// Optimized unification routine that avoids creating new inference 
@ -1870,7 +1870,7 @@ let MakeAndPublishSimpleVals cenv env m names mergeNamesInOneNameresEnv =
                        member this.NotifyExprHasType(_, _, _, _, _, _) = assert false // no expr typings in MakeSimpleVals
                        member this.NotifyFormatSpecifierLocation(_, _) = ()
                        member this.NotifyOpenDeclaration(_) = ()
-                        member this.CurrentSource = None 
+                        member this.CurrentSourceText = None 
                        member this.FormatStringCheckContext = None } 

                use _h = WithNewTypecheckResultsSink(sink, cenv.tcSink)
@ -6925,7 +6925,7 @@ and TcRecdExpr cenv overallTy env tpenv (inherits, optOrigExpr, flds, mWholeExpr
    let requiresCtor = (GetCtorShapeCounter env = 1) // Get special expression forms for constructors 
    let haveCtor = Option.isSome inherits

-    let optOrigExprInfo, tpenv = 
+    let optOrigExpr, tpenv = 
      match optOrigExpr with 
      | None -> None, tpenv 
      | Some (origExpr, _) -> 
@ -6933,10 +6933,9 @@ and TcRecdExpr cenv overallTy env tpenv (inherits, optOrigExpr, flds, mWholeExpr
          | Some (_, _, mInherits, _, _) -> error(Error(FSComp.SR.tcInvalidRecordConstruction(), mInherits))
          | None -> 
              let olde, tpenv = TcExpr cenv overallTy env tpenv origExpr
-              let oldvaddr, oldvaddre = mkCompGenLocal mWholeExpr "inputRecord" (if isStructTy cenv.g overallTy then mkByrefTy cenv.g overallTy else overallTy)
-              Some (olde, oldvaddr, oldvaddre), tpenv
+              Some (olde), tpenv

-    let hasOrigExpr = optOrigExprInfo.IsSome
+    let hasOrigExpr = optOrigExpr.IsSome

    let fldsList = 
        let flds = 
@ -6963,6 +6962,13 @@ and TcRecdExpr cenv overallTy env tpenv (inherits, optOrigExpr, flds, mWholeExpr
                | Some v -> yield n, v
                | None -> () ]

+    let optOrigExprInfo =
+        match optOrigExpr with
+        | None -> None
+        | Some(olde) ->
+            let oldvaddr, oldvaddre = mkCompGenLocal mWholeExpr "inputRecord" (if isStructTy cenv.g overallTy then mkByrefTy cenv.g overallTy else overallTy)
+            Some(olde, oldvaddr, oldvaddre)
+
    if hasOrigExpr && not (isRecdTy cenv.g overallTy) then 
        errorR(Error(FSComp.SR.tcExpressionFormRequiresRecordTypes(), mWholeExpr))

@ -11626,7 +11632,7 @@ and AnalyzeAndMakeAndPublishRecursiveValue overridesOK isGeneratedEventVal cenv

    // Suppress hover tip for "get" and "set" at property definitions, where toolId <> bindingId
    match toolIdOpt with 
-    | Some tid when not tid.idRange.IsSynthetic && tid.idRange <> bindingId.idRange -> 
+    | Some tid when not tid.idRange.IsSynthetic && not (Range.equals tid.idRange bindingId.idRange) ->
        let item = Item.Value (mkLocalValRef vspec)
        CallNameResolutionSink cenv.tcSink (tid.idRange, env.NameEnv, item, item, emptyTyparInst, ItemOccurence.RelatedText, env.DisplayEnv, env.eAccessRights)
    | _ -> ()
--- a/src/fsharp/UnicodeLexing.fs
+++ b/src/fsharp/UnicodeLexing.fs
@ -6,7 +6,7 @@ module internal FSharp.Compiler.UnicodeLexing
 // Functions for Unicode char-based lexing (new code).
 //

-open FSharp.Compiler.AbstractIL.Internal.Library 
+open FSharp.Compiler.AbstractIL.Internal.Library
 open Internal.Utilities
 open System.IO 

@ -19,6 +19,9 @@ let StringAsLexbuf (s:string) : Lexbuf =
  
 let FunctionAsLexbuf (bufferFiller: char[] * int * int -> int) : Lexbuf =
    LexBuffer<_>.FromFunction bufferFiller 
+
+let SourceTextAsLexbuf sourceText =
+    LexBuffer<char>.FromSourceText(sourceText)
     
 // The choice of 60 retries times 50 ms is not arbitrary. The NTFS FILETIME structure 
 // uses 2 second resolution for LastWriteTime. We retry long enough to surpass this threshold 
--- a/src/fsharp/UnicodeLexing.fsi
+++ b/src/fsharp/UnicodeLexing.fsi
@ -2,6 +2,7 @@

 module internal FSharp.Compiler.UnicodeLexing

+open FSharp.Compiler.Text
 open Microsoft.FSharp.Text
 open Internal.Utilities.Text.Lexing

@ -9,3 +10,4 @@ type Lexbuf =  LexBuffer<char>
 val internal StringAsLexbuf : string -> Lexbuf
 val public FunctionAsLexbuf : (char [] * int * int -> int) -> Lexbuf
 val public UnicodeFileAsLexbuf :string * int option * (*retryLocked*) bool -> Lexbuf
+val public SourceTextAsLexbuf : ISourceText -> Lexbuf
--- a/src/fsharp/fsc.fs
+++ b/src/fsharp/fsc.fs
@ -142,11 +142,12 @@ type InProcErrorLoggerProvider() =

                    member this.HandleTooManyErrors(text) = warnings.Add(Diagnostic.Short(false, text))

-                    member this.HandleIssue(tcConfigBuilder, err, isError) = 
-                        let errs = 
+                    member this.HandleIssue(tcConfigBuilder, err, isError) =
+                        // 'true' is passed for "suggestNames", since we want to suggest names with fsc.exe runs and this doesn't affect IDE perf
+                        let errs =
                            CollectDiagnostic
-                                (tcConfigBuilder.implicitIncludeDir, tcConfigBuilder.showFullPaths, 
-                                 tcConfigBuilder.flatErrors, tcConfigBuilder.errorStyle, isError, err)
+                                (tcConfigBuilder.implicitIncludeDir, tcConfigBuilder.showFullPaths,
+                                 tcConfigBuilder.flatErrors, tcConfigBuilder.errorStyle, isError, err, true)
                        let container = if isError then errors else warnings 
                        container.AddRange(errs) } 
                :> ErrorLogger }
@ -227,10 +228,10 @@ let AdjustForScriptCompile(ctok, tcConfigB: TcConfigBuilder, commandLineSourceFi

            // Record the references from the analysis of the script. The full resolutions are recorded as the corresponding #I paths used to resolve them
            // are local to the scripts and not added to the tcConfigB (they are added to localized clones of the tcConfigB).
-            let references = 
-                closure.References 
-                |> List.collect snd 
-                |> List.filter (fun r -> r.originalReference.Range<>range0 && r.originalReference.Range<>rangeStartup)
+            let references =
+                closure.References
+                |> List.collect snd
+                |> List.filter (fun r -> not (Range.equals r.originalReference.Range range0) && not (Range.equals r.originalReference.Range rangeStartup))

            references |> List.iter (fun r -> tcConfigB.AddReferencedAssemblyByPath(r.originalReference.Range, r.resolvedPath))
            closure.NoWarns |> List.collect (fun (n, ms) -> ms|>List.map(fun m->m, n)) |> List.iter (fun (x,m) -> tcConfigB.TurnWarningOff(x, m))
--- a/src/fsharp/fsc/app.config
+++ b/src/fsharp/fsc/app.config
@ -6,7 +6,7 @@
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="FSharp.Core" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
-        <bindingRedirect oldVersion="2.0.0.0-4.5.0.0" newVersion="4.5.0.0"/>
+        <bindingRedirect oldVersion="2.0.0.0-4.6.0.0" newVersion="4.6.0.0"/>
      </dependentAssembly>
        <dependentAssembly>
          <assemblyIdentity name="System.Collections.Immutable" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
--- a/src/fsharp/fsc/fsc.fsproj
+++ b/src/fsharp/fsc/fsc.fsproj
@ -4,17 +4,16 @@

  <PropertyGroup>
    <OutputType>Exe</OutputType>
-    <TargetFrameworks>net46;netcoreapp2.1</TargetFrameworks>
+    <TargetFrameworks>net472;netcoreapp2.1</TargetFrameworks>
    <TargetFrameworks Condition="'$(OS)' == 'Unix'">netcoreapp2.1</TargetFrameworks>
    <TargetExt>.exe</TargetExt>
    <NoWarn>$(NoWarn);45;55;62;75;1204</NoWarn>
    <AllowCrossTargeting>true</AllowCrossTargeting>
    <OtherFlags>$(OtherFlags) --maxerrors:20 --extraoptimizationloops:1</OtherFlags>
-    <UseAssetTargetFallback>true</UseAssetTargetFallback>
    <NGenBinary>true</NGenBinary>
  </PropertyGroup>

-  <PropertyGroup Condition="'$(TargetFramework)' == 'net46'">
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net472'">
    <PlatformTarget>x86</PlatformTarget>
  </PropertyGroup>

--- a/src/fsharp/fsi/app.config
+++ b/src/fsharp/fsi/app.config
@ -5,7 +5,7 @@
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="FSharp.Core" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
-        <bindingRedirect oldVersion="2.0.0.0-4.5.0.0" newVersion="4.5.0.0"/>
+        <bindingRedirect oldVersion="2.0.0.0-4.6.0.0" newVersion="4.6.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Collections.Immutable" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
--- a/src/fsharp/fsi/fsi.fs
+++ b/src/fsharp/fsi/fsi.fs
@ -48,6 +48,7 @@ open FSharp.Compiler.TypeChecker
 open FSharp.Compiler.Tast
 open FSharp.Compiler.Tastops
 open FSharp.Compiler.TcGlobals
+open FSharp.Compiler.Text
 open FSharp.Compiler.SourceCodeServices
 open FSharp.Compiler.ReferenceResolver

@ -2321,7 +2322,7 @@ type internal FsiInteractionProcessor
        let tcConfig = TcConfig.Create(tcConfigB,validate=false)

        let fsiInteractiveChecker = FsiInteractiveChecker(legacyReferenceResolver, checker, tcConfig, istate.tcGlobals, istate.tcImports, istate.tcState)
-        fsiInteractiveChecker.ParseAndCheckInteraction(ctok, text)
+        fsiInteractiveChecker.ParseAndCheckInteraction(ctok, SourceText.ofString text)


 //----------------------------------------------------------------------------
@ -2560,7 +2561,8 @@ type FsiEvaluationSession (fsi: FsiEvaluationSessionHostConfig, argv:string[], i
            | Choice2Of2 None -> Choice2Of2 (System.Exception "Operation could not be completed due to earlier error")
            | Choice2Of2 (Some userExn) -> Choice2Of2 userExn

-        userRes, ErrorHelpers.CreateErrorInfos (errorOptions, true, scriptFile, errs)
+        // 'true' is passed for "suggestNames" because we want the FSI session to suggest names for misspellings and it won't affect IDE perf much
+        userRes, ErrorHelpers.CreateErrorInfos (errorOptions, true, scriptFile, errs, true)

    let dummyScriptFileName = "input.fsx"

--- a/src/fsharp/fsi/fsi.fsproj
+++ b/src/fsharp/fsi/fsi.fsproj
@ -4,18 +4,17 @@

  <PropertyGroup>
    <OutputType>Exe</OutputType>
-    <TargetFrameworks>net46;netcoreapp2.1</TargetFrameworks>
+    <TargetFrameworks>net472;netcoreapp2.1</TargetFrameworks>
    <TargetFrameworks Condition="'$(OS)' == 'Unix'">netcoreapp2.1</TargetFrameworks>
    <TargetExt>.exe</TargetExt>
    <NoWarn>$(NoWarn);45;55;62;75;1204</NoWarn>
    <AllowCrossTargeting>true</AllowCrossTargeting>
    <OtherFlags>$(OtherFlags)  --warnon:1182 --maxerrors:20 --extraoptimizationloops:1</OtherFlags>
    <Win32Resource>fsi.res</Win32Resource>
-    <UseAssetTargetFallback>true</UseAssetTargetFallback>
    <NGenBinary>true</NGenBinary>
  </PropertyGroup>

-  <PropertyGroup Condition="'$(TargetFramework)' == 'net46'">
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net472'">
    <PlatformTarget>x86</PlatformTarget>
    <DefineConstants>$(DefineConstants);FSI_SHADOW_COPY_REFERENCES;FSI_SERVER</DefineConstants>
  </PropertyGroup>
@ -31,14 +30,11 @@
    <ProjectReference Include="..\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj" />
    <ProjectReference Include="..\FSharp.Compiler.Interactive.Settings\FSharp.Compiler.Interactive.Settings.fsproj" />

-    <!-- only used when '$(TargetFramework)' == 'netstandard2.0' -->
-    <ProjectReference Include="..\FSharp.Build\FSharp.Build.fsproj" Condition="'$(TargetFramework)' == 'netstandard2.0'" />
-
-    <!-- only used when '$(TargetFramework)' == 'net46' -->
-    <ProjectReference Include="..\FSharp.Compiler.Server.Shared\FSharp.Compiler.Server.Shared.fsproj" Condition="'$(TargetFramework)' == 'net46'" />
+    <!-- only used when '$(TargetFramework)' == 'net472' -->
+    <ProjectReference Include="..\FSharp.Compiler.Server.Shared\FSharp.Compiler.Server.Shared.fsproj" Condition="'$(TargetFramework)' == 'net472'" />
  </ItemGroup>

-  <ItemGroup Condition="'$(TargetFramework)' == 'net46'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'net472'">
    <Reference Include="System.Drawing" />
    <Reference Include="System.Windows.Forms" />
    <Reference Include="PresentationCore" />
--- a/src/fsharp/fsi/xlf/FSIstrings.txt.cs.xlf
+++ b/src/fsharp/fsi/xlf/FSIstrings.txt.cs.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="cs" original="../FSIstrings.resx">
    <body>
@ -264,7 +264,7 @@
      </trans-unit>
      <trans-unit id="shadowCopyReferences">
        <source>Prevents references from being locked by the F# Interactive process</source>
-        <target state="translated">Znemožňuje zamknutí referencí procesem nástroje F# Interactive.</target>
+        <target state="translated">Znemožňuje zamknutí referencí interaktivním procesem jazyka F#.</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/fsi/xlf/FSIstrings.txt.de.xlf
+++ b/src/fsharp/fsi/xlf/FSIstrings.txt.de.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="de" original="../FSIstrings.resx">
    <body>
@ -134,7 +134,7 @@
      </trans-unit>
      <trans-unit id="fsiExceptionDuringPrettyPrinting">
        <source>\n\nException raised during pretty printing.\nPlease report this so it can be fixed.\nTrace: {0}\n</source>
-        <target state="translated">\n\nAusnahme beim Schöndruck.\nMelden Sie dies, damit das Problem behoben werden kann.\nAblaufverfolgung: {0}\n</target>
+        <target state="translated">\n\nAusnahme bei der automatischen Strukturierung und Einrückung.\nMelden Sie dies, damit das Problem behoben werden kann.\nAblaufverfolgung: {0}\n</target>
        <note />
      </trans-unit>
      <trans-unit id="fsiIntroTextHeader1directives">
@ -264,7 +264,7 @@
      </trans-unit>
      <trans-unit id="shadowCopyReferences">
        <source>Prevents references from being locked by the F# Interactive process</source>
-        <target state="translated">Verhindert, dass Verweise vom F# Interactive-Prozess gesperrt werden</target>
+        <target state="translated">Verhindert, dass Verweise vom interaktiven Prozess F# gesperrt werden</target>
        <note />
      </trans-unit>
    </body>
--- a/src/fsharp/fsi/xlf/FSIstrings.txt.es.xlf
+++ b/src/fsharp/fsi/xlf/FSIstrings.txt.es.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="es" original="../FSIstrings.resx">
    <body>
@ -99,7 +99,7 @@
      </trans-unit>
      <trans-unit id="fsiConsoleProblem">
        <source>A problem occurred starting the F# Interactive process. This may be due to a known problem with background process console support for Unicode-enabled applications on some Windows systems. Try selecting Tools-&gt;Options-&gt;F# Interactive for Visual Studio and enter '--fsi-server-no-unicode'.</source>
-        <target state="translated">Se produjo un problema al iniciar el proceso de F# interactivo. Esto puede deberse a un problema conocido de compatibilidad de la consola de procesos en segundo plano con aplicaciones habilitadas para Unicode en algunos sistemas Windows. Pruebe lo siguiente: seleccione Herramientas-&gt;Opciones-&gt;F# interactivo para Visual Studio y escriba “--fsi-server-no-unicode”.</target>
+        <target state="translated">Se produjo un problema al iniciar el proceso de F# interactivo. Esto puede deberse a un problema conocido de compatibilidad de la consola de procesos en segundo plano con aplicaciones habilitadas para Unicode en algunos sistemas Windows. Pruebe lo siguiente: seleccione Herramientas-&gt;Opciones-&gt;F# interactivo para Visual Studio y escriba '--fsi-server-no-unicode'.</target>
        <note />
      </trans-unit>
      <trans-unit id="fsiInvalidAssembly">
@ -139,7 +139,7 @@
      </trans-unit>
      <trans-unit id="fsiIntroTextHeader1directives">
        <source>  F# Interactive directives:</source>
-        <target state="translated">  Directivas de F# interactivo:</target>
+        <target state="translated">  Directivas de F#:</target>
        <note />
      </trans-unit>
      <trans-unit id="fsiIntroTextHashrInfo">
@ -214,7 +214,7 @@
      </trans-unit>
      <trans-unit id="fsiDidAHashrWithLockWarning">
        <source>--&gt; Referenced '{0}' (file may be locked by F# Interactive process)</source>
-        <target state="translated">--&gt; “{0}” al que se hace referencia (el archivo puede estar bloqueado por un proceso de F# interactivo)</target>
+        <target state="translated">--&gt; '{0}' al que se hace referencia (el archivo puede estar bloqueado por un proceso de F# interactivo)</target>
        <note />
      </trans-unit>
      <trans-unit id="fsiDidAHashrWithStaleWarning">
@ -259,7 +259,7 @@
      </trans-unit>
      <trans-unit id="fsiProductNameCommunity">
        <source>F# Interactive for F# {0}</source>
-        <target state="translated">F# interactivo para F# {0}</target>
+        <target state="translated">F# Interactive para F# {0}</target>
        <note />
      </trans-unit>
      <trans-unit id="shadowCopyReferences">
--- a/src/fsharp/fsi/xlf/FSIstrings.txt.fr.xlf
+++ b/src/fsharp/fsi/xlf/FSIstrings.txt.fr.xlf
@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
  <file datatype="xml" source-language="en" target-language="fr" original="../FSIstrings.resx">
    <body>
@ -134,7 +134,7 @@
      </trans-unit>
      <trans-unit id="fsiExceptionDuringPrettyPrinting">
        <source>\n\nException raised during pretty printing.\nPlease report this so it can be fixed.\nTrace: {0}\n</source>
-        <target state="translated">\n\nException déclenchée durant l'impression automatique.\nSignalez ce problème afin qu'il soit corrigé.\nTrace : {0}\n</target>
+        <target state="translated">\n\nException déclenchée pendant le listing en mode Pretty. \nSignalez ce problème afin qu'il soit corrigé.\nTrace : {0}\n</target>
        <note />
      </trans-unit>
      <trans-unit id="fsiIntroTextHeader1directives">
--- a/Показать больше
+++ b/Показать больше