Fix Internal error when analysing incomplete inherit member

docs/release-notes/.FSharp.Compiler.Service/9.0.200.md

@@ -6,6 +6,8 @@
 * Ensure `frameworkTcImportsCache` mutations are thread-safe. ([PR #17795](https://github.com/dotnet/fsharp/pull/17795))
 * Fix concurrency issue in `ILPreTypeDefImpl`  ([PR #17812](https://github.com/dotnet/fsharp/pull/17812))
 * Fix nullness inference for member val and other OO scenarios  ([PR #17845](https://github.com/dotnet/fsharp/pull/17845))
+* Fix internal error when analyzing incomplete inherit member ([PR #17905](https://github.com/dotnet/fsharp/pull/17905))
+
 
 ### Added
 * Deprecate places where `seq` can be omitted. ([Language suggestion #1033](https://github.com/fsharp/fslang-suggestions/issues/1033), [PR #17772](https://github.com/dotnet/fsharp/pull/17772))

src/Compiler/Checking/CheckDeclarations.fs

@@ -4473,7 +4473,7 @@ module TcDeclarations =
             let implements2 = members |> List.choose (function SynMemberDefn.Interface (interfaceType=ty) -> Some(ty, ty.Range) | _ -> None)
             let inherits =
                 members |> List.choose (function 
-                    | SynMemberDefn.Inherit (ty, idOpt, m, _) -> Some(ty, m, idOpt)
+                    | SynMemberDefn.Inherit (Some ty, idOpt, m, _) -> Some(ty, m, idOpt)
                     | SynMemberDefn.ImplicitInherit (ty, _, idOpt, m) -> Some(ty, m, idOpt)
                     | _ -> None)
 

src/Compiler/Driver/GraphChecking/FileContentMapping.fs

@@ -220,7 +220,8 @@ let visitSynMemberDefn (md: SynMemberDefn) : FileContentEntry list =
         | SynMemberDefn.Interface(interfaceType, _, members, _) ->
             yield! visitSynType interfaceType
             yield! collectFromOption (List.collect visitSynMemberDefn) members
-        | SynMemberDefn.Inherit(baseType = t) -> yield! visitSynType t
+        | SynMemberDefn.Inherit(baseType = Some baseType) -> yield! visitSynType baseType
+        | SynMemberDefn.Inherit(baseType = None) -> ()
         | SynMemberDefn.ValField(fieldInfo, _) -> yield! visitSynField fieldInfo
         | SynMemberDefn.NestedType _ -> ()
         | SynMemberDefn.AutoProperty(attributes = attributes; typeOpt = typeOpt; synExpr = synExpr) ->

src/Compiler/Service/ServiceParseTreeWalk.fs

@@ -996,7 +996,8 @@ module SyntaxTraversal =
 
                         |> pick x
                 | ok -> ok
-            | SynMemberDefn.Inherit(synType, _identOption, range, _) -> traverseInherit (synType, range)
+            | SynMemberDefn.Inherit(Some synType, _identOption, range, _) -> traverseInherit (synType, range)
+            | SynMemberDefn.Inherit(None, _, _, _) -> None
             | SynMemberDefn.ValField _ -> None
             | SynMemberDefn.NestedType(synTypeDefn, _synAccessOption, _range) -> traverseSynTypeDefn path synTypeDefn
 

src/Compiler/Service/ServiceParsedInputOps.fs

@@ -913,8 +913,8 @@ module ParsedInput =
                 walkType t
                 |> Option.orElseWith (fun () -> members |> Option.bind (List.tryPick walkMember))
 
-            | SynMemberDefn.Inherit(baseType = t) -> walkType t
-
+            | SynMemberDefn.Inherit(baseType = Some baseType) -> walkType baseType
+            | SynMemberDefn.Inherit(baseType = None) -> None
             | SynMemberDefn.ValField(fieldInfo = field) -> walkField field
 
             | SynMemberDefn.NestedType(tdef, _, _) -> walkTypeDefn tdef
@@ -2240,7 +2240,8 @@ module ParsedInput =
             | SynMemberDefn.Interface(interfaceType = t; members = members) ->
                 walkType t
                 members |> Option.iter (List.iter walkMember)
-            | SynMemberDefn.Inherit(baseType = t) -> walkType t
+            | SynMemberDefn.Inherit(baseType = Some baseType) -> walkType baseType
+            | SynMemberDefn.Inherit(baseType = None) -> ()
             | SynMemberDefn.ValField(fieldInfo = field) -> walkField field
             | SynMemberDefn.NestedType(tdef, _, _) -> walkTypeDefn tdef
             | SynMemberDefn.AutoProperty(attributes = Attributes attrs; typeOpt = t; synExpr = e) ->

src/Compiler/SyntaxTree/SyntaxTree.fs

@@ -37,7 +37,7 @@ type SynLongIdent =
 
     member this.Range =
         match this with
-        | SynLongIdent([], _, _) -> failwith "rangeOfLidwd"
+        | SynLongIdent([], _, _) -> failwith "rangeOfLid"
         | SynLongIdent([ id ], [], _) -> id.idRange
         | SynLongIdent([ id ], [ m ], _) -> unionRanges id.idRange m
         | SynLongIdent(h :: t, [], _) -> unionRanges h.idRange (List.last t).idRange
@@ -1496,7 +1496,7 @@ type SynMemberDefn =
 
     | Interface of interfaceType: SynType * withKeyword: range option * members: SynMemberDefns option * range: range
 
-    | Inherit of baseType: SynType * asIdent: Ident option * range: range * trivia: SynMemberDefnInheritTrivia
+    | Inherit of baseType: SynType option * asIdent: Ident option * range: range * trivia: SynMemberDefnInheritTrivia
 
     | ValField of fieldInfo: SynField * range: range
 

src/Compiler/SyntaxTree/SyntaxTree.fsi

@@ -1670,7 +1670,7 @@ type SynMemberDefn =
     | Interface of interfaceType: SynType * withKeyword: range option * members: SynMemberDefns option * range: range
 
     /// An 'inherit' definition within a class
-    | Inherit of baseType: SynType * asIdent: Ident option * range: range * trivia: SynMemberDefnInheritTrivia
+    | Inherit of baseType: SynType option * asIdent: Ident option * range: range * trivia: SynMemberDefnInheritTrivia
 
     /// A 'val' definition within a class
     | ValField of fieldInfo: SynField * range: range

src/Compiler/pars.fsy

@@ -2317,7 +2317,7 @@ inheritsDefn:
   | INHERIT atomTypeNonAtomicDeprecated optBaseSpec
      { let mDecl = unionRanges (rhs parseState 1) $2.Range
        let trivia = { InheritKeyword = rhs parseState 1 }
-       SynMemberDefn.Inherit($2, $3, mDecl, trivia) }
+       SynMemberDefn.Inherit(Some $2, $3, mDecl, trivia) }
 
   | INHERIT atomTypeNonAtomicDeprecated opt_HIGH_PRECEDENCE_APP atomicExprAfterType optBaseSpec
      { let mDecl = unionRanges (rhs parseState 1) $4.Range
@@ -2327,7 +2327,7 @@ inheritsDefn:
      { let mDecl = (rhs parseState 1)
        let trivia = { InheritKeyword = (rhs parseState 1) }
        if not $2 then errorR (Error(FSComp.SR.parsTypeNameCannotBeEmpty (), mDecl))
-       SynMemberDefn.Inherit(SynType.LongIdent(SynLongIdent([], [], [])), None, mDecl, trivia) }
+       SynMemberDefn.Inherit(None, None, mDecl, trivia) }
 
 optAsSpec:
   | asSpec

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

@@ -831,6 +831,18 @@ type Class() =
             (Error 961, Line 5, Col 5, Line 5, Col 12, "This 'inherit' declaration specifies the inherited type but no arguments. Consider supplying arguments, e.g. 'inherit BaseType(args)'.")
             (Error 946, Line 5, Col 13, Line 5, Col 15, "Cannot inherit from interface type. Use interface ... with instead.")
         ]
+
+    [<Fact>]
+    let ``This 'inherit' declaration specifies the inherited type but no arguments. Type name cannot be empty.`` () =
+        Fsx """
+type Class() =
+    inherit
+        """
+        |> typecheck
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 3159, Line 3, Col 5, Line 3, Col 12, "Type name cannot be empty.")
+        ]
 
     [<Fact>]
     let ``The types System.ValueType, System.Enum, System.Delegate, System.MulticastDelegate and System.Array cannot be used as super types in an object expression or class.`` () =

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

@@ -8070,8 +8070,8 @@ FSharp.Compiler.Syntax.SynMemberDefn+ImplicitInherit: FSharp.Compiler.Text.Range
 FSharp.Compiler.Syntax.SynMemberDefn+ImplicitInherit: FSharp.Compiler.Text.Range range
 FSharp.Compiler.Syntax.SynMemberDefn+ImplicitInherit: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident] get_inheritAlias()
 FSharp.Compiler.Syntax.SynMemberDefn+ImplicitInherit: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident] inheritAlias
-FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.Syntax.SynType baseType
-FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.Syntax.SynType get_baseType()
+FSharp.Compiler.Syntax.SynMemberDefn+Inherit: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.SynType] baseType
+FSharp.Compiler.Syntax.SynMemberDefn+Inherit: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.SynType] get_baseType()
 FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.Text.Range get_range()
 FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.Text.Range range
 FSharp.Compiler.Syntax.SynMemberDefn+Inherit: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident] asIdent
@@ -8153,7 +8153,7 @@ FSharp.Compiler.Syntax.SynMemberDefn: FSharp.Compiler.Syntax.SynMemberDefn NewIm
 FSharp.Compiler.Syntax.SynMemberDefn: FSharp.Compiler.Syntax.SynMemberDefn NewImplicitInherit(FSharp.Compiler.Syntax.SynType, FSharp.Compiler.Syntax.SynExpr, Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident], FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia get_trivia()
 FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia trivia
-FSharp.Compiler.Syntax.SynMemberDefn: FSharp.Compiler.Syntax.SynMemberDefn NewInherit(FSharp.Compiler.Syntax.SynType, Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident], FSharp.Compiler.Text.Range, FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia)
+FSharp.Compiler.Syntax.SynMemberDefn: FSharp.Compiler.Syntax.SynMemberDefn NewInherit(Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.SynType], Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident], FSharp.Compiler.Text.Range, FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia)
 FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia: FSharp.Compiler.Text.Range InheritKeyword
 FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia: FSharp.Compiler.Text.Range get_InheritKeyword()
 FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia: System.String ToString()

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

@@ -8070,8 +8070,8 @@ FSharp.Compiler.Syntax.SynMemberDefn+ImplicitInherit: FSharp.Compiler.Text.Range
 FSharp.Compiler.Syntax.SynMemberDefn+ImplicitInherit: FSharp.Compiler.Text.Range range
 FSharp.Compiler.Syntax.SynMemberDefn+ImplicitInherit: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident] get_inheritAlias()
 FSharp.Compiler.Syntax.SynMemberDefn+ImplicitInherit: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident] inheritAlias
-FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.Syntax.SynType baseType
-FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.Syntax.SynType get_baseType()
+FSharp.Compiler.Syntax.SynMemberDefn+Inherit: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.SynType] baseType
+FSharp.Compiler.Syntax.SynMemberDefn+Inherit: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.SynType] get_baseType()
 FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.Text.Range get_range()
 FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.Text.Range range
 FSharp.Compiler.Syntax.SynMemberDefn+Inherit: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident] asIdent
@@ -8153,7 +8153,7 @@ FSharp.Compiler.Syntax.SynMemberDefn: FSharp.Compiler.Syntax.SynMemberDefn NewIm
 FSharp.Compiler.Syntax.SynMemberDefn: FSharp.Compiler.Syntax.SynMemberDefn NewImplicitInherit(FSharp.Compiler.Syntax.SynType, FSharp.Compiler.Syntax.SynExpr, Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident], FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia get_trivia()
 FSharp.Compiler.Syntax.SynMemberDefn+Inherit: FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia trivia
-FSharp.Compiler.Syntax.SynMemberDefn: FSharp.Compiler.Syntax.SynMemberDefn NewInherit(FSharp.Compiler.Syntax.SynType, Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident], FSharp.Compiler.Text.Range, FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia)
+FSharp.Compiler.Syntax.SynMemberDefn: FSharp.Compiler.Syntax.SynMemberDefn NewInherit(Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.SynType], Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident], FSharp.Compiler.Text.Range, FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia)
 FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia: FSharp.Compiler.Text.Range InheritKeyword
 FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia: FSharp.Compiler.Text.Range get_InheritKeyword()
 FSharp.Compiler.SyntaxTrivia.SynMemberDefnInheritTrivia: System.String ToString()

tests/service/data/SyntaxTree/Member/Inherit 01.fs.bsl

@@ -12,7 +12,7 @@ ImplFile
                   ObjectModel
                     (Unspecified,
                      [Inherit
-                        (LongIdent (SynLongIdent ([I], [], [None])), None,
+                        (Some (LongIdent (SynLongIdent ([I], [], [None]))), None,
                          (4,4--4,13), { InheritKeyword = (4,4--4,11) })],
                      (4,4--4,13)), [], None, (3,5--4,13),
                   { LeadingKeyword = Type (3,0--3,4)

tests/service/data/SyntaxTree/Member/Inherit 03.fs.bsl

@@ -12,12 +12,11 @@ ImplFile
                   ObjectModel
                     (Unspecified,
                      [Inherit
-                        (LongIdent (SynLongIdent ([], [], [])), None,
-                         (4,4--4,11), { InheritKeyword = (4,4--4,11) })],
-                     (4,4--4,11)), [], None, (3,5--4,11),
-                  { LeadingKeyword = Type (3,0--3,4)
-                    EqualsRange = Some (3,7--3,8)
-                    WithKeyword = None })], (3,0--4,11))],
+                        (None, None, (4,4--4,11),
+                         { InheritKeyword = (4,4--4,11) })], (4,4--4,11)), [],
+                  None, (3,5--4,11), { LeadingKeyword = Type (3,0--3,4)
+                                       EqualsRange = Some (3,7--3,8)
+                                       WithKeyword = None })], (3,0--4,11))],
           PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
           (1,0--4,11), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
       { ConditionalDirectives = []

tests/service/data/SyntaxTree/Member/Inherit 04.fs.bsl

@@ -12,12 +12,11 @@ ImplFile
                   ObjectModel
                     (Unspecified,
                      [Inherit
-                        (LongIdent (SynLongIdent ([], [], [])), None,
-                         (4,4--4,11), { InheritKeyword = (4,4--4,11) })],
-                     (4,4--4,11)), [], None, (3,5--4,11),
-                  { LeadingKeyword = Type (3,0--3,4)
-                    EqualsRange = Some (3,7--3,8)
-                    WithKeyword = None })], (3,0--4,11));
+                        (None, None, (4,4--4,11),
+                         { InheritKeyword = (4,4--4,11) })], (4,4--4,11)), [],
+                  None, (3,5--4,11), { LeadingKeyword = Type (3,0--3,4)
+                                       EqualsRange = Some (3,7--3,8)
+                                       WithKeyword = None })], (3,0--4,11));
            Expr (Ident I, (6,0--6,1))],
           PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
           (1,0--6,1), { LeadingKeyword = Module (1,0--1,6) })], (true, true),

tests/service/data/SyntaxTree/Member/Inherit 05.fs.bsl

@@ -12,8 +12,8 @@ ImplFile
                   ObjectModel
                     (Unspecified,
                      [Inherit
-                        (LongIdent (SynLongIdent ([], [], [])), None,
-                         (4,4--4,11), { InheritKeyword = (4,4--4,11) });
+                        (None, None, (4,4--4,11),
+                         { InheritKeyword = (4,4--4,11) });
                       Member
                         (SynBinding
                            (None, Normal, false, false, [],

tests/service/data/SyntaxTree/Member/Inherit 08.fs.bsl

@@ -12,8 +12,8 @@ ImplFile
                   ObjectModel
                     (Unspecified,
                      [Inherit
-                        (LongIdent (SynLongIdent ([], [], [])), None,
-                         (4,4--4,11), { InheritKeyword = (4,4--4,11) });
+                        (None, None, (4,4--4,11),
+                         { InheritKeyword = (4,4--4,11) });
                       Member
                         (SynBinding
                            (None, Normal, false, false, [],

vsintegration/tests/UnitTests/LegacyLanguageService/Tests.LanguageService.Completion.fs

@@ -997,7 +997,7 @@ for i in 0..a."]
                 ]
             ]
         for ifs in shouldBeInterface do
-            AssertCtrlSpaceCompleteContains ifs "(*M*)" ["seq"] ["obj"]
+            AssertCtrlSpaceCompleteContains ifs "(*M*)" ["seq"] []
 
 
     [<Fact>]
@@ -1026,7 +1026,7 @@ for i in 0..a."]
                 ]
             ]
         for cls in shouldBeClass do
-            AssertCtrlSpaceCompleteContains cls "(*M*)" ["obj"] ["seq"]
+            AssertCtrlSpaceCompleteContains cls "(*M*)" ["obj"] []
 
     [<Fact>]
     member this.``Completion.DetectUnknownCompletionContext``() = 
@@ -1036,31 +1036,12 @@ for i in 0..a."]
                 "    inherit (*M*)"
             ]
 
-        AssertCtrlSpaceCompleteContains content "(*M*)" ["obj"; "seq"] ["abs"]
+        AssertCtrlSpaceCompleteContains content "(*M*)" ["obj"; "seq"] []
 
     [<Fact>]
     member this.``Completion.DetectInvalidCompletionContext``() = 
         let shouldBeInvalid = 
             [
-                [
-                    "type X = struct"
-                    "    inherit (*M*)"
-                ]
-                [
-                    "[<Interface>]"
-                    "type X = class"
-                    "    inherit (*M*)"
-                ]
-                [
-                    "[<Class>]"
-                    "type X = interface"
-                    "    inherit (*M*)"
-                ]
-                [
-                    "[<Struct>]"
-                    "type X = interface"
-                    "    inherit (*M*)"
-                ]
                 [
                     "type X ="
                     "    inherit System (*M*)."
@@ -1076,7 +1057,6 @@ for i in 0..a."]
         for invalid in shouldBeInvalid do
             AssertCtrlSpaceCompletionListIsEmpty invalid "(*M*)"
 
-
     [<Fact>]
     member this.``Completion.LongIdentifiers``() = 
         // System.Diagnostics.Debugger.Launch() |> ignore