More ValueOption in compiler: part 3 (and the last)

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

@@ -32,7 +32,7 @@
 * Autogenerated .Is* members for unions skipped for single-case unions. ([PR 16571](https://github.com/dotnet/fsharp/pull/16571))
 * `implicitCtorSynPats` in `SynTypeDefnSimpleRepr.General` is now `SynPat option` instead of `SynSimplePats option`. ([PR #16425](https://github.com/dotnet/fsharp/pull/16425))
 * `SyntaxVisitorBase<'T>.VisitSimplePats` now takes `SynPat` instead of `SynSimplePat list`. ([PR #16425](https://github.com/dotnet/fsharp/pull/16425))
-* Reduce allocations in compiler checking via `ValueOption` usage ([PR #16323](https://github.com/dotnet/fsharp/pull/16323), [PR #16567](https://github.com/dotnet/fsharp/pull/16567))
+* Reduce allocations in compiler checking via `ValueOption` usage ([PR #16323](https://github.com/dotnet/fsharp/pull/16323), [PR #16567](https://github.com/dotnet/fsharp/pull/16567), [PR #16822](https://github.com/dotnet/fsharp/pull/16822))
 * Reverted [#16348](https://github.com/dotnet/fsharp/pull/16348) `ThreadStatic` `CancellationToken` changes to improve test stability and prevent potential unwanted cancellations. ([PR #16536](https://github.com/dotnet/fsharp/pull/16536))
 * Refactored parenthesization API. ([PR #16461])(https://github.com/dotnet/fsharp/pull/16461))
 * Optimize some interpolated strings by lowering to string concatenation. ([PR #16556](https://github.com/dotnet/fsharp/pull/16556))

src/Compiler/Driver/CompilerDiagnostics.fs

@@ -610,10 +610,11 @@ module OldStyleMessages =
 let mutable showParserStackOnParseError = false
 #endif
 
+[<return: Struct>]
 let (|InvalidArgument|_|) (exn: exn) =
     match exn with
-    | :? ArgumentException as e -> Some e.Message
-    | _ -> None
+    | :? ArgumentException as e -> ValueSome e.Message
+    | _ -> ValueNone
 
 let OutputNameSuggestions (os: StringBuilder) suggestNames suggestionsF idText =
     if suggestNames then

src/Compiler/Driver/CreateILModule.fs

@@ -54,11 +54,12 @@ module AttributeHelpers =
             | Some(Attrib(_, _, [ AttribBoolArg p ], _, _, _, _)) -> Some p
             | _ -> None
 
+    [<return: Struct>]
     let (|ILVersion|_|) (versionString: string) =
         try
-            Some(parseILVersion versionString)
+            ValueSome(parseILVersion versionString)
         with e ->
-            None
+            ValueNone
 
 //----------------------------------------------------------------------------
 // ValidateKeySigningAttributes, GetStrongNameSigner

src/Compiler/Driver/GraphChecking/FileContentMapping.fs

@@ -330,7 +330,8 @@ let visitNameofResult (nameofResult: NameofResult) : FileContentEntry =
         FileContentEntry.PrefixedIdentifier(longIdentToPath false longIdent)
 
 /// Special case of `nameof Module` type of expression
-let (|NameofExpr|_|) (e: SynExpr) : NameofResult option =
+[<return: Struct>]
+let (|NameofExpr|_|) (e: SynExpr) : NameofResult voption =
     let rec stripParen (e: SynExpr) =
         match e with
         | SynExpr.Paren(expr = expr) -> stripParen expr
@@ -339,15 +340,15 @@ let (|NameofExpr|_|) (e: SynExpr) : NameofResult option =
     match e with
     | SynExpr.App(flag = ExprAtomicFlag.NonAtomic; isInfix = false; funcExpr = SynExpr.Ident NameofIdent; argExpr = moduleNameExpr) ->
         match stripParen moduleNameExpr with
-        | SynExpr.Ident moduleNameIdent -> Some(NameofResult.SingleIdent moduleNameIdent)
+        | SynExpr.Ident moduleNameIdent -> ValueSome(NameofResult.SingleIdent moduleNameIdent)
         | SynExpr.LongIdent(longDotId = longIdent) ->
             match longIdent.LongIdent with
-            | [] -> None
+            | [] -> ValueNone
             // This is highly unlikely to be produced by the parser
-            | [ moduleNameIdent ] -> Some(NameofResult.SingleIdent moduleNameIdent)
-            | lid -> Some(NameofResult.LongIdent(lid))
-        | _ -> None
-    | _ -> None
+            | [ moduleNameIdent ] -> ValueSome(NameofResult.SingleIdent moduleNameIdent)
+            | lid -> ValueSome(NameofResult.LongIdent(lid))
+        | _ -> ValueNone
+    | _ -> ValueNone
 
 let visitSynExpr (e: SynExpr) : FileContentEntry list =
     let rec visit (e: SynExpr) (continuation: FileContentEntry list -> FileContentEntry list) : FileContentEntry list =
@@ -566,6 +567,7 @@ let visitSynExpr (e: SynExpr) : FileContentEntry list =
     visit e id
 
 /// Special case of `| nameof Module ->` type of pattern
+[<return: Struct>]
 let (|NameofPat|_|) (pat: SynPat) =
     let rec stripPats p =
         match p with
@@ -582,11 +584,11 @@ let (|NameofPat|_|) (pat: SynPat) =
             argPats = SynArgPats.Pats []
             accessibility = None) ->
             match longIdent with
-            | [] -> None
-            | [ moduleNameIdent ] -> Some(NameofResult.SingleIdent moduleNameIdent)
-            | lid -> Some(NameofResult.LongIdent lid)
-        | _ -> None
-    | _ -> None
+            | [] -> ValueNone
+            | [ moduleNameIdent ] -> ValueSome(NameofResult.SingleIdent moduleNameIdent)
+            | lid -> ValueSome(NameofResult.LongIdent lid)
+        | _ -> ValueNone
+    | _ -> ValueNone
 
 let visitPat (p: SynPat) : FileContentEntry list =
     let rec visit (p: SynPat) (continuation: FileContentEntry list -> FileContentEntry list) : FileContentEntry list =

src/Compiler/Facilities/AsyncMemoize.fs

@@ -30,15 +30,16 @@ module internal Utils =
 
     let replayDiagnostics (logger: DiagnosticsLogger) = Seq.iter ((<|) logger.DiagnosticSink)
 
+    [<return: Struct>]
     let (|TaskCancelled|_|) (ex: exn) =
         match ex with
-        | :? System.Threading.Tasks.TaskCanceledException as tce -> Some tce
+        | :? System.Threading.Tasks.TaskCanceledException as tce -> ValueSome tce
         //| :? System.AggregateException as ae ->
         //    if ae.InnerExceptions |> Seq.forall (fun e -> e :? System.Threading.Tasks.TaskCanceledException) then
         //        ae.InnerExceptions |> Seq.tryHead |> Option.map (fun e -> e :?> System.Threading.Tasks.TaskCanceledException)
         //    else
         //        None
-        | _ -> None
+        | _ -> ValueNone
 
 type internal StateUpdate<'TValue> =
     | CancelRequest

src/Compiler/Facilities/AsyncMemoize.fsi

@@ -9,7 +9,8 @@ module internal Utils =
     /// Return file name with one directory above it
     val shortPath: path: string -> string
 
-    val (|TaskCancelled|_|): ex: exn -> TaskCanceledException option
+    [<return: Struct>]
+    val (|TaskCancelled|_|): ex: exn -> TaskCanceledException voption
 
 type internal JobEvent =
     | Requested

src/Compiler/Facilities/DiagnosticsLogger.fs

@@ -67,10 +67,11 @@ exception StopProcessingExn of exn option with
         | StopProcessingExn(Some exn) -> "StopProcessingExn, originally (" + exn.ToString() + ")"
         | _ -> "StopProcessingExn"
 
+[<return: Struct>]
 let (|StopProcessing|_|) exn =
     match exn with
-    | StopProcessingExn _ -> Some()
-    | _ -> None
+    | StopProcessingExn _ -> ValueSome()
+    | _ -> ValueNone
 
 let StopProcessing<'T> = StopProcessingExn None
 

src/Compiler/Facilities/DiagnosticsLogger.fsi

@@ -37,7 +37,8 @@ val NoSuggestions: Suggestions
 /// Thrown when we stop processing the F# Interactive entry or #load.
 exception StopProcessingExn of exn option
 
-val (|StopProcessing|_|): exn: exn -> unit option
+[<return: Struct>]
+val (|StopProcessing|_|): exn: exn -> unit voption
 
 val StopProcessing<'T> : exn