Merge pull request #15621 from dotnet/merges/main-to-release/dev17.8

Merge main to release/dev17.8

src/Compiler/Checking/CheckDeclarations.fs

@@ -915,6 +915,7 @@ module MutRecBindingChecking =
                             let innerState = (incrClassCtorLhsOpt, envForTycon, tpenv, recBindIdx, uncheckedBindsRev)     
                             [Phase2AIncrClassBindings (tcref, letBinds, isStatic, isRec, m)], innerState
 
+                        | SynMemberDefn.Member(SynBinding(headPat = SynPat.Wild _; expr = SynExpr.ArbitraryAfterError _), _), _
                         | SynMemberDefn.Member(SynBinding(headPat = SynPat.FromParseError(SynPat.Wild _, _)), _), _ ->
                             [], innerState
 

src/Compiler/Checking/CheckExpressions.fs

@@ -3930,7 +3930,7 @@ let GetInstanceMemberThisVariable (vspec: Val, expr) =
     // Skip over LAM tps. Choose 'a.
     if vspec.IsInstanceMember then
         let rec firstArg e =
-          match stripDebugPoints e with
+            match stripDebugPoints e with
             | Expr.TyLambda (_, _, b, _, _) -> firstArg b
             | Expr.TyChoose (_, b, _) -> firstArg b
             | Expr.Lambda (_, _, _, [v], _, _, _) -> Some v

src/Compiler/Driver/CompilerDiagnostics.fs

@@ -388,7 +388,7 @@ type PhasedDiagnostic with
             match x.Exception with
             | DiagnosticEnabledWithLanguageFeature (_, _, _, enabled) -> enabled
             | _ ->
-                (severity = FSharpDiagnosticSeverity.Info)
+                (severity = FSharpDiagnosticSeverity.Info && level > 0)
                 || (severity = FSharpDiagnosticSeverity.Warning && level >= x.WarningLevel)
 
     /// Indicates if a diagnostic should be reported as an informational

src/Compiler/FSComp.txt

@@ -1526,7 +1526,6 @@ notAFunctionButMaybeDeclaration,"This value is not a function and cannot be appl
 3351,chkFeatureNotRuntimeSupported,"Feature '%s' is not supported by target runtime."
 3352,typrelInterfaceMemberNoMostSpecificImplementation,"Interface member '%s' does not have a most specific implementation."
 3353,chkFeatureNotSupportedInLibrary,"Feature '%s' requires the F# library for language version %s or greater."
-3360,parsEqualsMissingInTypeDefinition,"Unexpected token in type definition. Expected '=' after the type '%s'."
 useSdkRefs,"Use reference assemblies for .NET framework references when available (Enabled by default)."
 optsGetLangVersions,"Display the allowed values for language version."
 optsSetLangVersion,"Specify language version such as 'latest' or 'preview'."

src/Compiler/Service/FSharpParseFileResults.fs

@@ -505,6 +505,24 @@ type FSharpParseFileResults(diagnostics: FSharpDiagnostic[], input: ParsedInput,
         let result = SyntaxTraversal.Traverse(pos, input, visitor)
         result.IsSome
 
+    member _.IsPositionWithinTypeDefinition pos =
+        let visitor =
+            { new SyntaxVisitorBase<_>() with
+                override _.VisitComponentInfo(path, _) =
+                    let typeDefs =
+                        path
+                        |> List.filter (function
+                            | SyntaxNode.SynModule (SynModuleDecl.Types _) -> true
+                            | _ -> false)
+
+                    match typeDefs with
+                    | [] -> None
+                    | _ -> Some true
+            }
+
+        let result = SyntaxTraversal.Traverse(pos, input, visitor)
+        result.IsSome
+
     member _.IsBindingALambdaAtPosition pos =
         let visitor =
             { new SyntaxVisitorBase<_>() with

src/Compiler/Service/FSharpParseFileResults.fsi

@@ -68,6 +68,9 @@ type public FSharpParseFileResults =
     /// Determines if the expression or pattern at the given position has a type annotation
     member IsTypeAnnotationGivenAtPosition: pos -> bool
 
+    /// Determines if the given position is bound to a type definition
+    member IsPositionWithinTypeDefinition: pos -> bool
+
     /// Determines if the binding at the given position is bound to a lambda expression
     member IsBindingALambdaAtPosition: pos -> bool
 

src/Compiler/pars.fsy

@@ -1588,24 +1588,6 @@ tyconDefn:
            let trivia: SynTypeDefnTrivia = { LeadingKeyword = leadingKeyword; EqualsRange = None; WithKeyword = None }
            SynTypeDefn($1, SynTypeDefnRepr.Simple(SynTypeDefnSimpleRepr.None($1.Range), $1.Range), [], None, $1.Range, trivia) }
 
-  | typeNameInfo opt_equals tyconDefnRhsBlock
-     { match $2 with
-       | Some _ -> ()
-       | None ->
-            let (SynComponentInfo(_, _, _, lid, _, _, _, _)) = $1
-            // While the spec doesn't allow long idents here, the parser doesn't enforce this, so take one ident
-            let typeNameId = List.last lid
-            raiseParseErrorAt (rhs parseState 2) (FSComp.SR.parsEqualsMissingInTypeDefinition(typeNameId.ToString()))
-
-       let nameRange = rhs parseState 1
-       let (tcDefRepr: SynTypeDefnRepr), mWith, members = $3 nameRange
-       let declRange = unionRanges (rhs parseState 1) tcDefRepr.Range
-       let mWhole = (declRange, members) ||> unionRangeWithListBy (fun (mem: SynMemberDefn) -> mem.Range)
-
-       fun leadingKeyword ->
-           let trivia: SynTypeDefnTrivia = { LeadingKeyword = leadingKeyword; EqualsRange = $2; WithKeyword = mWith }
-           SynTypeDefn($1, tcDefRepr, members, None, mWhole, trivia) }
-
   | typeNameInfo tyconDefnAugmentation
      { let mWithKwd, classDefns = $2
        let m = (rhs parseState 1, classDefns) ||> unionRangeWithListBy (fun mem -> mem.Range)
@@ -1632,11 +1614,21 @@ tyconDefn:
 
        let tcDefRepr =
          match tcDefRepr, memberCtorPattern with
+         | SynTypeDefnRepr.Simple(SynTypeDefnSimpleRepr.None _, m), Some ctor ->
+             reportParseErrorAt m (FSComp.SR.parsEmptyTypeDefinition())
+             SynTypeDefnRepr.ObjectModel(SynTypeDefnKind.Unspecified, [ctor], unionRanges m mEquals)
+
+         | SynTypeDefnRepr.Simple(SynTypeDefnSimpleRepr.None mName, m), _ ->
+             reportParseErrorAt m (FSComp.SR.parsEmptyTypeDefinition())
+             tcDefRepr
+
          | SynTypeDefnRepr.ObjectModel(k, cspec, m), Some ctor ->
              SynTypeDefnRepr.ObjectModel(k, ctor :: cspec, m)
+
          | _, Some ctor ->
              reportParseErrorAt (rhs2 parseState 1 5) (FSComp.SR.parsOnlyClassCanTakeValueArguments ())
              tcDefRepr
+
          | _ ->
              match az with
              | Some(_, Some id) ->
@@ -1685,7 +1677,7 @@ tyconDefn:
 
        fun leadingKeyword ->
            let trivia = { SynTypeDefnTrivia.Zero with LeadingKeyword = leadingKeyword }
-           SynTypeDefn($1, SynTypeDefnRepr.Simple(SynTypeDefnSimpleRepr.None(mName), mName), members, None, mName, trivia) }
+           SynTypeDefn($1, SynTypeDefnRepr.Simple(SynTypeDefnSimpleRepr.None(mName), mName), members, None, mWhole, trivia) }
 
 
 /* The right-hand-side of a type definition */
@@ -1715,6 +1707,10 @@ tyconDefnRhsBlock:
            let tcDefRepr, members = $2 nameRange (checkForMultipleAugmentations m ($4 @ optClassDefn) [])
            tcDefRepr, mWith, members) }
 
+  | OBLOCKBEGIN oblockend
+     { fun mName ->
+           SynTypeDefnRepr.Simple(SynTypeDefnSimpleRepr.None mName, mName), None, [] }
+
   | tyconDefnRhs opt_classDefn
      { let m = rhs parseState 1
        let mWith, optClassDefn = $2
@@ -1775,15 +1771,15 @@ tyconClassDefn:
 
 /* The right-hand-side of a object type definition where the class/interface/struct kind has not been specified */
 classDefnBlockKindUnspecified:
-  | OBLOCKBEGIN classDefnMembers recover
+  | OBLOCKBEGIN classDefnMembersAtLeastOne recover
      { if not $3 then reportParseErrorAt (rhs parseState 3) (FSComp.SR.parsUnexpectedEndOfFileTypeDefinition())
        let mopt =
            match $2 with
            | _ :: _ -> Some((rhs parseState 1, $2) ||> unionRangeWithListBy (fun (d: SynMemberDefn) -> d.Range))
            | _ -> None
        false, $2, mopt }
 
-  | OBLOCKBEGIN classDefnMembers oblockend
+  | OBLOCKBEGIN classDefnMembersAtLeastOne oblockend
      { let mopt =
            match $2 with
            | _ :: _ -> Some((rhs parseState 1, $2) ||> unionRangeWithListBy (fun (d: SynMemberDefn) -> d.Range))

tests/FSharp.Compiler.ComponentTests/CompilerOptions/fsc/warn/warn.fs

@@ -11,10 +11,12 @@ module TestCompilerWarningLevel =
     [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"warn_level0.fs"|])>]
     let ``warn_level0_fs --warn:0`` compilation =
         compilation
+        |> withLangVersionPreview
         |> asExe
         |> withOptions ["--warn:0"]
         |> compileAndRun
         |> shouldSucceed
+        |> withDiagnostics []
 
     [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"warn_level1.fs"|])>]
     let ``warn_level1_fs --warn:1 --warnaserror:52`` compilation =

tests/FSharp.Compiler.ComponentTests/CompilerOptions/fsc/warn/warn_level0.fs

@@ -1,2 +1,20 @@
 // #NoMT #CompilerOptions 
+
+[<NoComparison>]
+/// Meh - Informational diagnostics "XML comment is not placed on a valid language element."
+type A = int
+
+let x = 10
+// Normally a The result of this equality expression has type 'bool' and is implicitly discarded.
+x = 20
+
+let mul x y = x * y
+// Normally a warning
+[<TailCall>]
+let rec fact n acc =
+    if n = 0
+    then acc
+    else (fact (n - 1) (mul n acc)) + 23
+
+// Normally a 'Main module of program is empty: nothing will happen when it is run' warning
 ()

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/TypeAbbreviations/TypeAbbreviations.fs

@@ -128,7 +128,6 @@ module TypeAbbreviations =
         |> shouldFail
         |> withDiagnostics [
             (Error 10, Line 8, Col 1, Line 8, Col 5, "Incomplete structured construct at or before this point in type definition")
-            (Error 547, Line 6, Col 6, Line 6, Col 15, "A type definition requires one or more members or other declarations. If you intend to define an empty class, struct or interface, then use 'type ... = class end', 'interface end' or 'struct end'.")
         ]
 
     //SOURCE=E_IncorrectRightSide_Keyword.fsx SCFLAGS="--test:ErrorRanges"                                      # E_IncorrectRightSide_Keyword.fsx

tests/FSharp.Compiler.ComponentTests/ErrorMessages/TypeEqualsMissingTests.fs

@@ -16,6 +16,6 @@ module ``Type definition missing equals`` =
 type X | A | B
             """
             FSharpDiagnosticSeverity.Error
-            3360 
+            10 
             (2, 8, 2, 9)
-            "Unexpected token in type definition. Expected '=' after the type 'X'."
+            "Unexpected symbol '|' in type definition. Expected '=' or other token."

tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.debug.bsl

@@ -2077,6 +2077,7 @@ FSharp.Compiler.CodeAnalysis.FSharpChecker: Void ClearCache(System.Collections.G
 FSharp.Compiler.CodeAnalysis.FSharpChecker: Void ClearLanguageServiceRootCachesAndCollectAndFinalizeAllTransients()
 FSharp.Compiler.CodeAnalysis.FSharpChecker: Void InvalidateAll()
 FSharp.Compiler.CodeAnalysis.FSharpChecker: Void InvalidateConfiguration(FSharp.Compiler.CodeAnalysis.FSharpProjectOptions, Microsoft.FSharp.Core.FSharpOption`1[System.String])
+FSharp.Compiler.CodeAnalysis.FSharpParseFileResults: Boolean IsPositionWithinTypeDefinition(FSharp.Compiler.Text.Position)
 FSharp.Compiler.CodeAnalysis.FSharpParseFileResults: Boolean IsBindingALambdaAtPosition(FSharp.Compiler.Text.Position)
 FSharp.Compiler.CodeAnalysis.FSharpParseFileResults: Boolean IsPosContainedInApplication(FSharp.Compiler.Text.Position)
 FSharp.Compiler.CodeAnalysis.FSharpParseFileResults: Boolean IsPositionContainedInACurriedParameter(FSharp.Compiler.Text.Position)