Fix16572 - Enabling preview features causes an issue with main somehow.

docs/release-notes/.FSharp.Compiler.Service/8.0.300.md

@@ -6,7 +6,7 @@
 * Graph Based Checking doesn't throw on invalid parsed input so it can be used for IDE scenarios ([PR #16575](https://github.com/dotnet/fsharp/pull/16575), [PR #16588](https://github.com/dotnet/fsharp/pull/16588), [PR #16643](https://github.com/dotnet/fsharp/pull/16643))
 * Keep parens for problematic exprs (`if`, `match`, etc.) in `$"{(…):N0}"`, `$"{(…),-3}"`, etc. ([PR #16578](https://github.com/dotnet/fsharp/pull/16578))
 * Fix crash in DOTNET_SYSTEM_GLOBALIZATION_INVARIANT mode [#PR 16471](https://github.com/dotnet/fsharp/pull/16471))
-
+* Fix16572 - Fixed the preview feature enabling Is properties for union case did not work correctly with let rec and .fsi files ([PR #16657](https://github.com/dotnet/fsharp/pull/16657))
 
 ### Added
 

src/Compiler/Checking/CheckDeclarations.fs

@@ -4727,7 +4727,6 @@ module TcDeclarations =
                 let env = List.foldBack (AddLocalVal g cenv.tcSink scopem) idvs envForDecls
                 env)
 
-
     /// Bind a collection of mutually recursive declarations in a signature file
     let TcMutRecSignatureDecls (cenv: cenv) envInitial parent typeNames tpenv m scopem mutRecNSInfo (mutRecSigs: MutRecSigsInitialData) =
         let mutRecSigsAfterSplit = mutRecSigs |> MutRecShapes.mapTycons SplitTyconSignature
@@ -4739,6 +4738,18 @@ module TcDeclarations =
         // Updates the types of the modules to contain the contents so far, which now includes values and members
         MutRecBindingChecking.TcMutRecDefns_UpdateModuleContents mutRecNSInfo mutRecDefnsAfterCore
 
+        // Generate the union augmentation values for all tycons.
+        let mutable vals = List.empty
+        (envMutRec, mutRecDefnsAfterCore)
+        ||> MutRecShapes.iterTyconsWithEnv (fun envForDecls ((tyconCore, _, _), tyconOpt, _, _, _) ->
+            let (MutRecDefnsPhase1DataForTycon (isAtOriginalTyconDefn=isAtOriginalTyconDefn)) = tyconCore
+            match tyconOpt with
+            | Some tycon when isAtOriginalTyconDefn -> 
+                if tycon.IsUnionTycon && AddAugmentationDeclarations.ShouldAugmentUnion cenv.g tycon then
+                    let vspecs = AddAugmentationDeclarations.AddUnionAugmentationValues cenv envForDecls tycon
+                    vals <- vspecs @ vals
+            | _ -> ())
+
         // By now we've established the full contents of type definitions apart from their
         // members and any fields determined by implicit construction. We know the kinds and 
         // representations of types and have established them as valid.
@@ -4747,28 +4758,19 @@ module TcDeclarations =
         //
         // Note: This environment reconstruction doesn't seem necessary. We're about to create Val's for all members, 
         // which does require type checking, but no more information than is already available.
-        let envMutRecPrelimWithReprs, withEnvs =  
+
+        let envMutRecPrelimWithReprs, withEnvs =
             (envInitial, MutRecShapes.dropEnvs mutRecDefnsAfterCore) 
-                ||> MutRecBindingChecking.TcMutRecDefns_ComputeEnvs 
-                       (fun (_, tyconOpt, _, _, _) -> tyconOpt)  
-                       (fun _binds -> [ (* no values are available yet *) ]) 
-                       cenv true scopem m 
+            ||> MutRecBindingChecking.TcMutRecDefns_ComputeEnvs 
+                (fun (_, tyconOpt, _, _, _) -> tyconOpt)  
+                (fun _binds -> vals) 
+                cenv true scopem m 
 
         let mutRecDefnsAfterVals = TcMutRecSignatureDecls_Phase2 cenv scopem envMutRecPrelimWithReprs withEnvs
 
         // Updates the types of the modules to contain the contents so far, which now includes values and members
         MutRecBindingChecking.TcMutRecDefns_UpdateModuleContents mutRecNSInfo mutRecDefnsAfterVals
 
-        // Generate the union augmentation values for all tycons.
-        (envMutRec, mutRecDefnsAfterCore) ||> MutRecShapes.iterTyconsWithEnv (fun envForDecls ((tyconCore, _, _), tyconOpt, _, _, _) -> 
-            let (MutRecDefnsPhase1DataForTycon (isAtOriginalTyconDefn=isAtOriginalTyconDefn)) = tyconCore
-            match tyconOpt with 
-            | Some tycon when isAtOriginalTyconDefn -> 
-                if tycon.IsUnionTycon && AddAugmentationDeclarations.ShouldAugmentUnion cenv.g tycon then
-                    let vspecs = AddAugmentationDeclarations.AddUnionAugmentationValues cenv envForDecls tycon
-                    ignore vspecs
-            | _ -> ())
-
         envMutRec
 
 //-------------------------------------------------------------------------

tests/FSharp.Compiler.ComponentTests/Conformance/Types/UnionTypes/UnionTypes.fs

@@ -609,3 +609,64 @@ module UnionTypes =
         |> withDiagnostics [
             (Warning 42, Line 11, Col 12, Line 11, Col 24, "This construct is deprecated: it is only for use in the F# library")
         ]
+
+    [<Theory>]
+    [<InlineData(false)>]
+    [<InlineData(true)>]
+    let ``UnionCaseIsTester inlined and SignatureData`` userec =
+
+        let kwrec = if userec then "rec" else ""
+        let myLibraryFsi =
+            SourceCodeFileKind.Create(
+                "myLibrary.fsi",
+                $"""
+module {kwrec} MyLibrary
+
+    [<RequireQualifiedAccess>]
+    type PrimaryAssembly =
+        | Mscorlib
+        | System_Runtime
+        | NetStandard""")
+
+        let myLibraryFs =
+            SourceCodeFileKind.Create(
+                "myLibrary.fs",
+                $"""
+module {kwrec} MyLibrary
+
+    [<RequireQualifiedAccess>]
+    type PrimaryAssembly =
+        | Mscorlib
+        | System_Runtime
+        | NetStandard
+                """)
+
+        let myFileFs =
+            SourceCodeFileKind.Create(
+                "myFile.fs",
+                $"""
+module {kwrec} FileName
+
+    open MyLibrary
+    let inline getAssemblyType () = PrimaryAssembly.NetStandard
+    let inline isNetStandard () = (PrimaryAssembly.NetStandard).IsNetStandard
+                """)
+
+        let myLibrary =
+            (fsFromString myLibraryFsi) |> FS
+            |> withAdditionalSourceFiles [myLibraryFs; myFileFs]
+            |> asLibrary
+            |> withLangVersionPreview
+            |> withName "MyLibrary"
+
+        Fs """
+let x = FileName.getAssemblyType().IsNetStandard
+let y = FileName.getAssemblyType()
+let z = FileName.isNetStandard()
+printfn "%b %A %b" x y z
+           """
+            |> asExe
+            |> withReferences [myLibrary]
+            |> withLangVersionPreview
+            |> compileAndRun
+            |> shouldSucceed

tests/FSharp.Compiler.ComponentTests/Language/DiscriminatedUnionTests.fs

@@ -2,10 +2,12 @@
 
 namespace Language
 
+open Xunit
 open FSharp.Test.Compiler
 
 module DiscriminatedUnionTests =
-    [<FSharp.Test.FactForNETCOREAPP>]
+
+    [<Fact>]
     let ``Simple Is* discriminated union properties are visible, proper values are returned`` () =
         Fsx """
 type Foo = | Foo of string | Bar
@@ -17,7 +19,7 @@ if foo.IsBar then failwith "Should not be Bar"
         |> compileExeAndRun
         |> shouldSucceed
 
-    [<FSharp.Test.FactForNETCOREAPP>]
+    [<Fact>]
     let ``Simple Is* discriminated union properties are not visible for a single case union`` () =
         Fsx """
 type Foo = Bar of string
@@ -31,7 +33,7 @@ if not foo.IsBar then failwith "Should be Bar"
         |> withDiagnostics  [Error 39, Line 4, Col 12, Line 4, Col 17, "The type 'Foo' does not define the field, constructor or member 'IsBar'. Maybe you want one of the following:
    Bar"]
 
-    [<FSharp.Test.FactForNETCOREAPP>]
+    [<Fact>]
     let ``Simple Is* discriminated union property satisfies SRTP constraint`` () =
         Fsx """
 type X =
@@ -47,7 +49,7 @@ X.A "a" |> test
         |> compileExeAndRun
         |> shouldSucceed
 
-    [<FSharp.Test.FactForNETCOREAPP>]
+    [<Fact>]
     let ``Lowercase Is* discriminated union properties are visible, proper values are returned`` () =
         Fsx """
 [<RequireQualifiedAccess>]
@@ -63,7 +65,7 @@ if foo.IsA then failwith "Should not be A"
         |> compileExeAndRun
         |> shouldSucceed
 
-    [<FSharp.Test.FactForNETCOREAPP>]
+    [<Fact>]
     let ``Is* discriminated union properties with backticks are visible, proper values are returned`` () =
         Fsx """
 type Foo = | Foo of string | ``Mars Bar``
@@ -79,7 +81,7 @@ if not marsbar.``IsMars Bar`` then failwith "Should be ``Mars Bar``"
         |> compileExeAndRun
         |> shouldSucceed
 
-    [<FSharp.Test.FactForNETCOREAPP>]
+    [<Fact>]
     let ``Is* discriminated union properties are visible, proper values are returned in recursive namespace, before the definition`` () =
         FSharp """
 namespace rec Hello
@@ -102,7 +104,7 @@ type Foo =
         |> shouldSucceed
 
 
-    [<FSharp.Test.FactForNETCOREAPP>]
+    [<Fact>]
     let ``Is* discriminated union properties are visible, proper values are returned in recursive namespace, in SRTP`` () =
         FSharp """
 namespace Hello
@@ -130,7 +132,7 @@ module Main =
         |> compileExeAndRun
         |> shouldSucceed
 
-    [<FSharp.Test.FactForNETCOREAPP>]
+    [<Fact>]
     let ``Is* discriminated union properties are unavailable with DefaultAugmentation(false)`` () =
         Fsx """
 [<DefaultAugmentation(false)>]
@@ -144,19 +146,40 @@ let isFoo = foo.IsFoo
         |> withErrorMessage "The type 'Foo' does not define the field, constructor or member 'IsFoo'. Maybe you want one of the following:
    Foo"
 
-    [<FSharp.Test.FactForNETCOREAPP>]
-    let ``Is* discriminated union properties are unavailable on voption`` () =
+    [<Fact>]
+    let ``Is* discriminated union properties are unavailable on union case with lang version 8`` () =
         Fsx """
-let x = (ValueSome 1).IsSome
-let y = ValueOption<int>.None.IsValueNone
+[<RequireQualifiedAccess>]
+type PrimaryAssembly =
+| Mscorlib
+| System_Runtime
+| NetStandard
+
+let x = (PrimaryAssembly.Mscorlib).IsMscorlib
         """
-        |> withLangVersionPreview
+        |> withLangVersion80
         |> typecheck
         |> shouldFail
-        |> withErrorMessage "The type 'ValueOption<_>' does not define the field, constructor or member 'IsValueNone'. Maybe you want one of the following:
-   ValueNone"
+        |> withErrorMessage "The type 'PrimaryAssembly' does not define the field, constructor or member 'IsMscorlib'. Maybe you want one of the following:
+   Mscorlib"
+
+
+    [<Fact>]
+    let ``Is* discriminated union properties are available on union case after lang version 8`` () =
+        Fsx """
+[<RequireQualifiedAccess>]
+type PrimaryAssembly =
+| Mscorlib
+| System_Runtime
+| NetStandard
+
+let x = (PrimaryAssembly.Mscorlib).IsMscorlib
+        """
+        |> withLangVersionPreview
+        |> compileExeAndRun
+        |> shouldSucceed
 
-    [<FSharp.Test.FactForNETCOREAPP>]
+    [<Fact>]
     let ``Is* discriminated union properties work with UseNullAsTrueValue`` () =
         Fsx """
 [<CompilationRepresentation(CompilationRepresentationFlags.UseNullAsTrueValue)>]