Replace (nearly) all ref cells in the compiler with mutable values (#8063)

* # This is a combination of 9 commits.
# This is the 1st commit message:

ref -> mutable in more places in the compiler

# The commit message #2 will be skipped:

# Update dependencies from https://github.com/dotnet/arcade build 20191229.1
#
# - Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19629.1

# The commit message #3 will be skipped:

# Update dependencies from https://github.com/dotnet/arcade build 20191230.1
#
# - Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19630.1

# The commit message #4 will be skipped:

# Update dependencies from https://github.com/dotnet/arcade build 20191231.1
#
# - Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19631.1

# The commit message #5 will be skipped:

# Update dependencies from https://github.com/dotnet/arcade build 20200101.1
#
# - Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.20051.1

# The commit message #6 will be skipped:

# Update dependencies from https://github.com/dotnet/arcade build 20191216.5 (#8079)
#
# - Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19616.5

# The commit message #7 will be skipped:

# dispose fsi at the end of a scripting session (#8084)
#

# The commit message #8 will be skipped:

# Added static link tests and extended CompilerAssert (#8101)
#
# * Changed CompilerAssert to static class. Added Compile/Execute methods that take a Compilation description. Added static link tests
# 
# * Hiding compilation description internals
# 
# * Added another test to check for sanity
# 
# * Making a few optional parameters
# 
# * Hiding internals of CompilationReference

# The commit message #9 will be skipped:

# Parameterize product version (#8031)
#
# * Parameterize Product details
# 
# * fcs
# 
# * Repack pkgdef

* no ilread

Author: cartermp

src/absil/ilascii.fs

@@ -9,7 +9,7 @@ open FSharp.Compiler.AbstractIL.IL
 
 // set to the proper value at CompileOps.fs (BuildFrameworkTcImports)
 // Only relevant when compiling FSharp.Core.dll
-let parseILGlobals = ref EcmaMscorlibILGlobals
+let mutable parseILGlobals = EcmaMscorlibILGlobals
 
 /// Table of parsing and pretty printing data for instructions.
 let noArgInstrs =

src/absil/ilascii.fsi

@@ -14,7 +14,7 @@ open FSharp.Compiler.AbstractIL.IL
 // IL Parser state - must be initialized before parsing a module
 // -------------------------------------------------------------------- 
 
-val parseILGlobals: ILGlobals ref
+val mutable parseILGlobals: ILGlobals
 
 // -------------------------------------------------------------------- 
 // IL Lexer and pretty-printer tables

src/absil/ildiag.fs

@@ -5,18 +5,18 @@
 module internal FSharp.Compiler.AbstractIL.Diagnostics 
 
 
-let diagnosticsLog = ref (Some stdout)
+let mutable diagnosticsLog = Some stdout
 
-let setDiagnosticsChannel s = diagnosticsLog := s 
+let setDiagnosticsChannel s = diagnosticsLog <- s 
 
-let dflushn () = match !diagnosticsLog with None -> () | Some d -> d.WriteLine(); d.Flush()
-let dflush () = match !diagnosticsLog with None -> () | Some d -> d.Flush()
+let dflushn () = match diagnosticsLog with None -> () | Some d -> d.WriteLine(); d.Flush()
+let dflush () = match diagnosticsLog with None -> () | Some d -> d.Flush()
 let dprintn (s:string) = 
-    match !diagnosticsLog with None -> () | Some d -> d.Write s; d.Write "\n"; dflush()
+    match diagnosticsLog with None -> () | Some d -> d.Write s; d.Write "\n"; dflush()
 
 let dprintf (fmt: Format<_,_,_,_>) = 
-    Printf.kfprintf dflush (match !diagnosticsLog with None -> System.IO.TextWriter.Null | Some d -> d) fmt
+    Printf.kfprintf dflush (match diagnosticsLog with None -> System.IO.TextWriter.Null | Some d -> d) fmt
 
 let dprintfn (fmt: Format<_,_,_,_>) = 
-    Printf.kfprintf dflushn (match !diagnosticsLog with None -> System.IO.TextWriter.Null | Some d -> d) fmt
+    Printf.kfprintf dflushn (match diagnosticsLog with None -> System.IO.TextWriter.Null | Some d -> d) fmt
 

src/absil/illib.fs

@@ -47,15 +47,15 @@ let LOH_SIZE_THRESHOLD_BYTES = 80_000
 // Library: ReportTime
 //---------------------------------------------------------------------
 let reportTime =
-    let tFirst = ref None
-    let tPrev = ref None
+    let mutable tFirst =None
+    let mutable tPrev = None
     fun showTimes descr ->
         if showTimes then 
             let t = Process.GetCurrentProcess().UserProcessorTime.TotalSeconds
-            let prev = match !tPrev with None -> 0.0 | Some t -> t
-            let first = match !tFirst with None -> (tFirst := Some t; t) | Some t -> t
+            let prev = match tPrev with None -> 0.0 | Some t -> t
+            let first = match tFirst with None -> (tFirst <- Some t; t) | Some t -> t
             printf "ilwrite: TIME %10.3f (total)   %10.3f (delta) - %s\n" (t - first) (t - prev) descr
-            tPrev := Some t
+            tPrev <- Some t
 
 //-------------------------------------------------------------------------
 // Library: projections
@@ -573,10 +573,10 @@ module String =
     let getLines (str: string) =
         use reader = new StringReader(str)
         [|
-            let line = ref (reader.ReadLine())
-            while not (isNull !line) do
-                yield !line
-                line := reader.ReadLine()
+            let mutable line = reader.ReadLine()
+            while not (isNull line) do
+                yield line
+                line <- reader.ReadLine()
             if str.EndsWithOrdinal("\n") then
                 // last trailing space not returned
                 // http://stackoverflow.com/questions/19365404/stringreader-omits-trailing-linebreak

src/absil/ilpars.fsy

@@ -33,7 +33,7 @@ let resolveCurrentMethodSpecScope obj =
 
 
 let findSystemRuntimeAssemblyRef() = 
-  match (!parseILGlobals).primaryAssemblyScopeRef with
+  match parseILGlobals.primaryAssemblyScopeRef with
   | ILScopeRef.Assembly aref -> aref
   | _ -> pfailwith "systemRuntimeScopeRef not set to valid assembly reference in parseILGlobals"
 
@@ -235,9 +235,9 @@ callKind:
  *---------------------------------------------*/
 
 typ: STRING
-       { noMethodSpecScope (!parseILGlobals).typ_String } 
+       { noMethodSpecScope parseILGlobals.typ_String } 
    | OBJECT
-       { noMethodSpecScope (!parseILGlobals).typ_Object } 
+       { noMethodSpecScope parseILGlobals.typ_Object } 
    | CLASS typeNameInst
        { resolveMethodSpecScopeThen $2 (fun tspec -> 
           noMethodSpecScope (mkILBoxedType tspec)) } 
@@ -256,45 +256,45 @@ typ: STRING
    | typ STAR
        { resolveMethodSpecScopeThen $1 (fun ty -> noMethodSpecScope (ILType.Ptr ty)) }
    | CHAR
-       { noMethodSpecScope (!parseILGlobals).typ_Char }
+       { noMethodSpecScope parseILGlobals.typ_Char }
    | VOID
        { noMethodSpecScope ILType.Void }
    | BOOL
-       { noMethodSpecScope (!parseILGlobals).typ_Bool }
+       { noMethodSpecScope parseILGlobals.typ_Bool }
    | INT8
-       { noMethodSpecScope (!parseILGlobals).typ_SByte }
+       { noMethodSpecScope parseILGlobals.typ_SByte }
    | INT16              
-       { noMethodSpecScope (!parseILGlobals).typ_Int16 }
+       { noMethodSpecScope parseILGlobals.typ_Int16 }
    | INT32              
-       { noMethodSpecScope (!parseILGlobals).typ_Int32 }
+       { noMethodSpecScope parseILGlobals.typ_Int32 }
    | INT64              
-       { noMethodSpecScope (!parseILGlobals).typ_Int64 }
+       { noMethodSpecScope parseILGlobals.typ_Int64 }
    | FLOAT32            
-       { noMethodSpecScope (!parseILGlobals).typ_Single }
+       { noMethodSpecScope parseILGlobals.typ_Single }
    | FLOAT64            
-       { noMethodSpecScope (!parseILGlobals).typ_Double }
+       { noMethodSpecScope parseILGlobals.typ_Double }
    | UNSIGNED INT8      
-       { noMethodSpecScope (!parseILGlobals).typ_Byte }
+       { noMethodSpecScope parseILGlobals.typ_Byte }
    | UNSIGNED INT16     
-       { noMethodSpecScope (!parseILGlobals).typ_UInt16 }
+       { noMethodSpecScope parseILGlobals.typ_UInt16 }
    | UNSIGNED INT32     
-       { noMethodSpecScope (!parseILGlobals).typ_UInt32 }
+       { noMethodSpecScope parseILGlobals.typ_UInt32 }
    | UNSIGNED INT64     
-       { noMethodSpecScope (!parseILGlobals).typ_UInt64 }
+       { noMethodSpecScope parseILGlobals.typ_UInt64 }
    | UINT8      
-       { noMethodSpecScope (!parseILGlobals).typ_Byte }
+       { noMethodSpecScope parseILGlobals.typ_Byte }
    | UINT16     
-       { noMethodSpecScope (!parseILGlobals).typ_UInt16 }
+       { noMethodSpecScope parseILGlobals.typ_UInt16 }
    | UINT32     
-       { noMethodSpecScope (!parseILGlobals).typ_UInt32 }
+       { noMethodSpecScope parseILGlobals.typ_UInt32 }
    | UINT64     
-       { noMethodSpecScope (!parseILGlobals).typ_UInt64 }
+       { noMethodSpecScope parseILGlobals.typ_UInt64 }
    | NATIVE INT         
-       { noMethodSpecScope (!parseILGlobals).typ_IntPtr }
+       { noMethodSpecScope parseILGlobals.typ_IntPtr }
    | NATIVE UNSIGNED INT  
-       { noMethodSpecScope (!parseILGlobals).typ_UIntPtr }
+       { noMethodSpecScope parseILGlobals.typ_UIntPtr }
    | NATIVE UINT  
-       { noMethodSpecScope (!parseILGlobals).typ_UIntPtr }
+       { noMethodSpecScope parseILGlobals.typ_UIntPtr }
 
    | BANG int32
        { noMethodSpecScope (ILType.TypeVar (uint16 ( $2)))  }

src/fsharp/CompileOps.fs

@@ -2479,7 +2479,7 @@ type AssemblyResolution =
       resolvedPath: string    
       prepareToolTip: unit -> string
       sysdir: bool 
-      ilAssemblyRef: ILAssemblyRef option ref
+      mutable ilAssemblyRef: ILAssemblyRef option
     }
     override this.ToString() = sprintf "%s%s" (if this.sysdir then "[sys]" else "") this.resolvedPath
 
@@ -2494,7 +2494,7 @@ type AssemblyResolution =
     //
     member this.GetILAssemblyRef(ctok, reduceMemoryUsage, tryGetMetadataSnapshot) = 
       cancellable {
-        match !this.ilAssemblyRef with 
+        match this.ilAssemblyRef with 
         | Some assemblyRef -> return assemblyRef
         | None ->
             let! assemblyRefOpt = 
@@ -2522,7 +2522,7 @@ type AssemblyResolution =
                           tryGetMetadataSnapshot = tryGetMetadataSnapshot } 
                     use reader = OpenILModuleReader this.resolvedPath readerSettings
                     mkRefToILAssembly reader.ILModuleDef.ManifestOfAssembly
-            this.ilAssemblyRef := Some assemblyRef
+            this.ilAssemblyRef <- Some assemblyRef
             return assemblyRef
       }
 
@@ -2892,7 +2892,7 @@ type TcConfig private (data: TcConfigBuilder, validate: bool) =
                   resolvedPath = resolved
                   prepareToolTip = (fun () -> resolved)
                   sysdir = sysdir
-                  ilAssemblyRef = ref None }
+                  ilAssemblyRef = None }
         | None -> 
 
         if String.Compare(ext, ".dll", StringComparison.OrdinalIgnoreCase)=0 
@@ -2927,7 +2927,7 @@ type TcConfig private (data: TcConfigBuilder, validate: bool) =
                             let line(append: string) = append.Trim([|' '|])+"\n"
                             line resolved + line fusionName)
                       sysdir = sysdir
-                      ilAssemblyRef = ref None }
+                      ilAssemblyRef = None }
             | None -> None
         else None
 
@@ -3057,7 +3057,7 @@ type TcConfig private (data: TcConfigBuilder, validate: bool) =
                                                       resolvedPath=canonicalItemSpec 
                                                       prepareToolTip = (fun () -> resolvedFile.prepareToolTip (originalReference.Text, canonicalItemSpec))
                                                       sysdir= tcConfig.IsSystemAssembly canonicalItemSpec
-                                                      ilAssemblyRef = ref None })
+                                                      ilAssemblyRef = None })
                                     (maxIndexOfReference, assemblyResolutions))
 
             // When calculating the resulting resolutions, we're going to use the index of the reference
@@ -3395,7 +3395,7 @@ let ParseOneInputLexbuf (tcConfig: TcConfig, lexResourceManager, conditionalComp
     try 
         let skip = true in (* don't report whitespace from lexer *)
         let lightSyntaxStatus = LightSyntaxStatus (tcConfig.ComputeLightSyntaxInitialStatus filename, true) 
-        let lexargs = mkLexargs (filename, conditionalCompilationDefines@tcConfig.conditionalCompilationDefines, lightSyntaxStatus, lexResourceManager, ref [], errorLogger, tcConfig.pathMap)
+        let lexargs = mkLexargs (filename, conditionalCompilationDefines@tcConfig.conditionalCompilationDefines, lightSyntaxStatus, lexResourceManager, [], errorLogger, tcConfig.pathMap)
         let shortFilename = SanitizeFileName filename tcConfig.implicitIncludeDir 
         let input = 
             Lexhelp.usingLexbufForParsing (lexbuf, filename) (fun lexbuf ->
@@ -3525,24 +3525,24 @@ type TcAssemblyResolutions(tcConfig: TcConfig, results: AssemblyResolution list,
         let frameworkDLLs, nonFrameworkReferences = resolutions.GetAssemblyResolutions() |> List.partition (fun r -> r.sysdir) 
         let unresolved = resolutions.GetUnresolvedReferences()
 #if DEBUG
-        let itFailed = ref false
+        let mutable itFailed = false
         let addedText = "\nIf you want to debug this right now, attach a debugger, and put a breakpoint in 'CompileOps.fs' near the text '!itFailed', and you can re-step through the assembly resolution logic."
         unresolved 
         |> List.iter (fun (UnresolvedAssemblyReference(referenceText, _ranges)) ->
             if referenceText.Contains("mscorlib") then
                 System.Diagnostics.Debug.Assert(false, sprintf "whoops, did not resolve mscorlib: '%s'%s" referenceText addedText)
-                itFailed := true)
+                itFailed <- true)
         frameworkDLLs 
         |> List.iter (fun x ->
             if not(FileSystem.IsPathRootedShim(x.resolvedPath)) then
                 System.Diagnostics.Debug.Assert(false, sprintf "frameworkDLL should be absolute path: '%s'%s" x.resolvedPath addedText)
-                itFailed := true)
+                itFailed <- true)
         nonFrameworkReferences 
         |> List.iter (fun x -> 
             if not(FileSystem.IsPathRootedShim(x.resolvedPath)) then
                 System.Diagnostics.Debug.Assert(false, sprintf "nonFrameworkReference should be absolute path: '%s'%s" x.resolvedPath addedText) 
-                itFailed := true)
-        if !itFailed then
+                itFailed <- true)
+        if itFailed then
             // idea is, put a breakpoint here and then step through
             let assemblyList = TcAssemblyResolutions.GetAllDllReferences tcConfig
             let resolutions = TcAssemblyResolutions.ResolveAssemblyReferences (ctok, tcConfig, assemblyList, [])
@@ -4207,9 +4207,9 @@ and [<Sealed>] TcImports(tcConfigP: TcConfigProvider, initialResolutions: TcAsse
             let systemRuntimeContainsType =  
                 // NOTE: do not touch this, edit: but we did, we had no choice - TPs cannot hold a strong reference on TcImports "ever".
                 let tcImports = tcImportsWeak
-                let systemRuntimeContainsTypeRef = ref (fun typeName -> tcImports.SystemRuntimeContainsType typeName)
-                tcImportsStrong.AttachDisposeTypeProviderAction(fun () -> systemRuntimeContainsTypeRef := (fun _ -> raise (System.ObjectDisposedException("The type provider has been disposed"))))  
-                fun arg -> systemRuntimeContainsTypeRef.Value arg  
+                let mutable systemRuntimeContainsTypeRef = fun typeName -> tcImports.SystemRuntimeContainsType typeName
+                tcImportsStrong.AttachDisposeTypeProviderAction(fun () -> systemRuntimeContainsTypeRef <- fun _ -> raise (System.ObjectDisposedException("The type provider has been disposed")))
+                fun arg -> systemRuntimeContainsTypeRef arg  
 
             let providers = 
                 [ for designTimeAssemblyName in designTimeAssemblyNames do
@@ -4676,7 +4676,7 @@ and [<Sealed>] TcImports(tcConfigP: TcConfigProvider, initialResolutions: TcAsse
                             error(InternalError("BuildFrameworkTcImports: no successful import of "+coreLibraryResolution.resolvedPath, coreLibraryResolution.originalReference.Range))
                     | None -> 
                         error(InternalError(sprintf "BuildFrameworkTcImports: no resolution of '%s'" coreLibraryReference.Text, rangeStartup))
-                IlxSettings.ilxFsharpCoreLibAssemRef := 
+                IlxSettings.ilxFsharpCoreLibAssemRef <- 
                     (let scoref = fslibCcuInfo.ILScopeRef
                      match scoref with
                      | ILScopeRef.Assembly aref -> Some aref
@@ -4691,11 +4691,11 @@ and [<Sealed>] TcImports(tcConfigP: TcConfigProvider, initialResolutions: TcAsse
 
 #if DEBUG
         // the global_g reference cell is used only for debug printing
-        global_g := Some tcGlobals
+        global_g <- Some tcGlobals
 #endif
         // do this prior to parsing, since parsing IL assembly code may refer to mscorlib
 #if !NO_INLINE_IL_PARSER
-        FSharp.Compiler.AbstractIL.Internal.AsciiConstants.parseILGlobals := tcGlobals.ilg 
+        FSharp.Compiler.AbstractIL.Internal.AsciiConstants.parseILGlobals <- tcGlobals.ilg 
 #endif
         frameworkTcImports.SetTcGlobals tcGlobals
         return tcGlobals, frameworkTcImports
@@ -5035,8 +5035,8 @@ module private ScriptPreprocessClosure =
            (tcConfig: TcConfig, inp: ParsedInput, pathOfMetaCommandSource) = 
 
         let tcConfigB = tcConfig.CloneOfOriginalBuilder 
-        let nowarns = ref [] 
-        let getWarningNumber = fun () (m, s) -> nowarns := (s, m) :: !nowarns
+        let mutable nowarns = [] 
+        let getWarningNumber = fun () (m, s) -> nowarns <- (s, m) :: nowarns
         let addReferencedAssemblyByPath = fun () (m, s) -> tcConfigB.AddReferencedAssemblyByPath(m, s)
         let addLoadedSource = fun () (m, s) -> tcConfigB.AddLoadedSource(m, s, pathOfMetaCommandSource)
         try 
@@ -5056,7 +5056,7 @@ module private ScriptPreprocessClosure =
            (closureSources, tcConfig: TcConfig, codeContext, 
             lexResourceManager: Lexhelp.LexResourceManager) =
 
-        let tcConfig = ref tcConfig
+        let mutable tcConfig = tcConfig
 
         let observedSources = Observed()
         let rec loop (ClosureSource(filename, m, sourceText, parseRequired)) = 
@@ -5067,20 +5067,20 @@ module private ScriptPreprocessClosure =
                         let parseResult, parseDiagnostics =
                             let errorLogger = CapturingErrorLogger("FindClosureParse")                    
                             use _unwindEL = PushErrorLoggerPhaseUntilUnwind (fun _ -> errorLogger)
-                            let result = ParseScriptText (filename, sourceText, !tcConfig, codeContext, lexResourceManager, errorLogger) 
+                            let result = ParseScriptText (filename, sourceText, tcConfig, codeContext, lexResourceManager, errorLogger) 
                             result, errorLogger.Diagnostics
 
                         match parseResult with 
                         | Some parsedScriptAst ->                    
                             let errorLogger = CapturingErrorLogger("FindClosureMetaCommands")                    
                             use _unwindEL = PushErrorLoggerPhaseUntilUnwind (fun _ -> errorLogger)
                             let pathOfMetaCommandSource = Path.GetDirectoryName filename
-                            let preSources = (!tcConfig).GetAvailableLoadedSources()
+                            let preSources = tcConfig.GetAvailableLoadedSources()
 
-                            let tcConfigResult, noWarns = ApplyMetaCommandsFromInputToTcConfigAndGatherNoWarn (!tcConfig, parsedScriptAst, pathOfMetaCommandSource)
-                            tcConfig := tcConfigResult // We accumulate the tcConfig in order to collect assembly references
+                            let tcConfigResult, noWarns = ApplyMetaCommandsFromInputToTcConfigAndGatherNoWarn (tcConfig, parsedScriptAst, pathOfMetaCommandSource)
+                            tcConfig <- tcConfigResult // We accumulate the tcConfig in order to collect assembly references
 
-                            let postSources = (!tcConfig).GetAvailableLoadedSources()
+                            let postSources = tcConfig.GetAvailableLoadedSources()
                             let sources = if preSources.Length < postSources.Length then postSources.[preSources.Length..] else []
 
                             //for (_, subFile) in sources do
@@ -5094,7 +5094,7 @@ module private ScriptPreprocessClosure =
                                     yield ClosureFile(subFile, m, None, [], [], []) 
 
                             //printfn "yielding source %s" filename
-                            yield ClosureFile(filename, m, Some parsedScriptAst, parseDiagnostics, errorLogger.Diagnostics, !noWarns)
+                            yield ClosureFile(filename, m, Some parsedScriptAst, parseDiagnostics, errorLogger.Diagnostics, noWarns)
 
                         | None -> 
                             //printfn "yielding source %s (failed parse)" filename
@@ -5104,7 +5104,7 @@ module private ScriptPreprocessClosure =
                         //printfn "yielding non-script source %s" filename
                         yield ClosureFile(filename, m, None, [], [], []) ]
 
-        closureSources |> List.collect loop, !tcConfig
+        closureSources |> List.collect loop, tcConfig
 
     /// Reduce the full directive closure into LoadClosure
     let GetLoadClosure(ctok, rootFilename, closureFiles, tcConfig: TcConfig, codeContext) = 

src/fsharp/CompileOps.fsi

@@ -204,7 +204,7 @@ type AssemblyResolution =
        /// Whether or not this is an installed system assembly (for example, System.dll)
        sysdir: bool
        // Lazily populated ilAssemblyRef for this reference. 
-       ilAssemblyRef: ILAssemblyRef option ref  }
+       mutable ilAssemblyRef: ILAssemblyRef option }
 
 type UnresolvedAssemblyReference = UnresolvedAssemblyReference of string * AssemblyReference list