Parser: more unfinished type recovery (#15585)

* Parser: rework missing type body recovery

* Update baselines

* Adjust the code fix

* nah baselines

* Remove error declaration

---------

Co-authored-by: Petr <[email protected]>

Author: auduchinok

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))