Merge pull request #7125 from KevinRansom/langversion-nameof

Langversion for nameof feature

Author: KevinRansom

FSharpTests.Directory.Build.targets

@@ -13,6 +13,7 @@
               DisabledWarnings="$(NoWarn)"
               DotnetFsiCompilerPath="$(DotnetFsiCompilerPath)"
               FsiExec="@(FsiExec)"
+              LangVersion="$(LangVersion)"
               LCID="$(LCID)"
               LoadSources="@(LoadSource)"
               NoFramework="false"

src/fsharp/CompileOps.fs

@@ -4730,7 +4730,7 @@ and [<Sealed>] TcImports(tcConfigP: TcConfigProvider, initialResolutions: TcAsse
         let tcGlobals = TcGlobals(tcConfig.compilingFslib, ilGlobals, fslibCcu,
                                   tcConfig.implicitIncludeDir, tcConfig.mlCompatibility,
                                   tcConfig.isInteractive, tryFindSysTypeCcu, tcConfig.emitDebugInfoInQuotations,
-                                  tcConfig.noDebugData, tcConfig.pathMap)
+                                  tcConfig.noDebugData, tcConfig.pathMap, tcConfig.langVersion)
 
 #if DEBUG
         // the global_g reference cell is used only for debug printing

src/fsharp/FSharp.Build/Fsi.fs

@@ -29,6 +29,7 @@ type public Fsi () as this =
     let mutable disabledWarnings : string = null
     let mutable dotnetFsiCompilerPath : string = null
     let mutable fsiExec = false
+    let mutable langVersion : string = null
     let mutable noFramework = false
     let mutable optimize = true
     let mutable otherFlags : string = null
@@ -67,6 +68,7 @@ type public Fsi () as this =
 
         builder.AppendSwitchIfNotNull("--codepage:", codePage)
 
+        builder.AppendSwitchIfNotNull("--langversion:", langVersion)
         if noFramework then builder.AppendSwitch("--noframework")
 
         if defineConstants <> null then
@@ -167,6 +169,10 @@ type public Fsi () as this =
         with get() = vslcid
         and set(p) = vslcid <- p
 
+    member fsc.LangVersion
+        with get() = langVersion
+        and set(s) = langVersion <- s
+
     // --noframework
     member fsi.NoFramework
         with get() = noFramework 

src/fsharp/LanguageFeatures.fs

@@ -24,6 +24,7 @@ type LanguageFeature =
     | SingleUnderscorePattern = 2
     | WildCardInForLoop = 3
     | RelaxWhitespace = 4
+    | NameOf = 5
 
 /// LanguageVersion management
 type LanguageVersion (specifiedVersion) =
@@ -47,8 +48,7 @@ type LanguageVersion (specifiedVersion) =
         LanguageFeature.SingleUnderscorePattern, previewVersion
         LanguageFeature.WildCardInForLoop, previewVersion
         LanguageFeature.RelaxWhitespace, previewVersion
-
-        // Add new LanguageFeatures here ...
+        LanguageFeature.NameOf, previewVersion
         |]
 
     let specified =

src/fsharp/LanguageFeatures.fsi

@@ -11,6 +11,7 @@ type LanguageFeature =
     | SingleUnderscorePattern = 2
     | WildCardInForLoop = 3
     | RelaxWhitespace = 4
+    | NameOf = 5
 
 /// LanguageVersion management
 type LanguageVersion =

src/fsharp/NameResolution.fs

@@ -24,6 +24,7 @@ open FSharp.Compiler.AttributeChecking
 open FSharp.Compiler.InfoReader
 open FSharp.Compiler.PrettyNaming
 open FSharp.Compiler.Text
+open FSharp.Compiler.Features
 open System.Collections.Generic
 
 #if !NO_EXTENSIONTYPING
@@ -2444,7 +2445,16 @@ let rec ResolveExprLongIdentPrim sink (ncenv: NameResolver) first fullyQualified
                     | Exception e -> typeError := Some e; None
 
                 | true, res ->
-                    Some (FreshenUnqualifiedItem ncenv m res, [])
+                    let fresh = FreshenUnqualifiedItem ncenv m res
+                    match fresh with
+                    | Item.Value value ->
+                        let isNameOfOperator = valRefEq ncenv.g ncenv.g.nameof_vref value
+                        if isNameOfOperator && not (ncenv.g.langVersion.SupportsFeature LanguageFeature.NameOf) then
+                            // Do not resolve `nameof` if the feature is unsupported, even if it is FSharp.Core
+                            None
+                         else
+                            Some (fresh, [])
+                    | _ -> Some (fresh, [])
                 | _ ->
                     None
 

src/fsharp/TastOps.fs

@@ -22,6 +22,7 @@ open FSharp.Compiler.TcGlobals
 open FSharp.Compiler.Layout
 open FSharp.Compiler.Layout.TaggedTextOps
 open FSharp.Compiler.PrettyNaming
+open FSharp.Compiler.Features
 #if !NO_EXTENSIONTYPING
 open FSharp.Compiler.ExtensionTyping
 #endif
@@ -3206,10 +3207,10 @@ let isSizeOfValRef g vref =
     // There is an internal version of typeof defined in prim-types.fs that needs to be detected
     || (g.compilingFslib && vref.LogicalName = "sizeof") 
 
-let isNameOfValRef g vref = 
-    valRefEq g vref g.nameof_vref 
+let isNameOfValRef g vref =
+    valRefEq g vref g.nameof_vref
     // There is an internal version of nameof defined in prim-types.fs that needs to be detected
-    || (g.compilingFslib && vref.LogicalName = "nameof") 
+    || (g.compilingFslib && vref.LogicalName = "nameof")
 
 let isTypeDefOfValRef g vref = 
     valRefEq g vref g.typedefof_vref 
@@ -8568,8 +8569,8 @@ let IsSimpleSyntacticConstantExpr g inputExpr =
         | Expr.Op (TOp.UnionCase _, _, [], _)         // Nullary union cases
         | UncheckedDefaultOfExpr g _ 
         | SizeOfExpr g _ 
-        | TypeOfExpr g _ 
-        | NameOfExpr g _ -> true
+        | TypeOfExpr g _ -> true
+        | NameOfExpr g _ when g.langVersion.SupportsFeature LanguageFeature.NameOf -> true
         // All others are not simple constant expressions
         | _ -> false
 

src/fsharp/TcGlobals.fs

@@ -22,6 +22,7 @@ open FSharp.Compiler.Range
 open FSharp.Compiler.Ast
 open FSharp.Compiler.Lib
 open FSharp.Compiler.PrettyNaming
+open FSharp.Compiler.Features
 
 open Internal.Utilities
 
@@ -180,8 +181,8 @@ type public TcGlobals(compilingFslib: bool, ilg:ILGlobals, fslibCcu: CcuThunk, d
                       // The helper to find system types amongst referenced DLLs
                       tryFindSysTypeCcu, 
                       emitDebugInfoInQuotations: bool, noDebugData: bool,
-                      pathMap: PathMap) =
-      
+                      pathMap: PathMap, langVersion: LanguageVersion) =
+
   let vara = NewRigidTypar "a" envRange
   let varb = NewRigidTypar "b" envRange
   let varc = NewRigidTypar "c" envRange
@@ -239,7 +240,7 @@ type public TcGlobals(compilingFslib: bool, ilg:ILGlobals, fslibCcu: CcuThunk, d
   // Search for a type. If it is not found, leave a dangling CCU reference with some useful diagnostic information should
   // the type actually be dereferenced
   let findSysTypeCcu path typeName =
-      match tryFindSysTypeCcu path typeName with 
+      match tryFindSysTypeCcu path typeName with
       | None -> CcuThunk.CreateDelayed(dummyAssemblyNameCarryingUsefulErrorInformation path typeName)
       | Some ccu -> ccu
 
@@ -904,6 +905,7 @@ type public TcGlobals(compilingFslib: bool, ilg:ILGlobals, fslibCcu: CcuThunk, d
   member __.emitDebugInfoInQuotations      = emitDebugInfoInQuotations
   member __.directoryToResolveRelativePaths= directoryToResolveRelativePaths
   member __.pathMap = pathMap
+  member __.langVersion = langVersion
   member __.unionCaseRefEq x y = primUnionCaseRefEq compilingFslib fslibCcu x y
   member __.valRefEq x y = primValRefEq compilingFslib fslibCcu x y
   member __.fslibCcu                 = fslibCcu

src/fsharp/TypeChecker.fs

@@ -36,6 +36,7 @@ open FSharp.Compiler.ConstraintSolver
 open FSharp.Compiler.NameResolution
 open FSharp.Compiler.PrettyNaming
 open FSharp.Compiler.InfoReader
+open FSharp.Compiler.Features
 
 #if !NO_EXTENSIONTYPING
 open FSharp.Compiler.ExtensionTyping
@@ -8762,9 +8763,9 @@ and TcFunctionApplicationThen cenv overallTy env tpenv mExprAndArg expr exprty (
     // If the type of 'synArg' unifies as a function type, then this is a function application, otherwise
     // it is an error or a computation expression
     match UnifyFunctionTypeUndoIfFailed cenv denv mFunExpr exprty with
-    | ValueSome (domainTy, resultTy) -> 
+    | ValueSome (domainTy, resultTy) ->
         match expr with
-        | ApplicableExpr(_, NameOfExpr cenv.g _, _) ->
+        | ApplicableExpr(_, NameOfExpr cenv.g _, _) when cenv.g.langVersion.SupportsFeature LanguageFeature.NameOf ->
             let replacementExpr = TcNameOfExpr cenv env tpenv synArg
             TcDelayed cenv overallTy env tpenv mExprAndArg (ApplicableExpr(cenv, replacementExpr, true)) cenv.g.string_ty ExprAtomicFlag.Atomic delayed
         | _ ->

tests/FSharp.Core.UnitTests/FSharp.Core.UnitTests.fsproj

@@ -66,7 +66,6 @@
     <Compile Include="FSharp.Core\Microsoft.FSharp.Core\IntConversions.fs" />
     <Compile Include="FSharp.Core\Microsoft.FSharp.Core\IntConversionsGenerated.fs" />
     <None Include="FSharp.Core\Microsoft.FSharp.Core\IntConversionsTestGenerator.fsx" />
-    <Compile Include="FSharp.Core\Microsoft.FSharp.Core\NameOfTests.fs" />
     <Compile Include="FSharp.Core\Microsoft.FSharp.Core\OptionModule.fs" />
     <Compile Include="FSharp.Core\Microsoft.FSharp.Core\PrintfTests.fs" />
     <Compile Include="FSharp.Core\Microsoft.FSharp.Core\ResultTests.fs" />