Minor code clean-ups and performance improvements

src/Common/Collections.fs

@@ -49,7 +49,7 @@ module internal List =
             f x
             g ()
             iterInterleaved f g (y :: tl)
-        | x :: [] -> f x
+        | [ x ] -> f x
         | [] -> ()
 
     /// Tests whether a list starts with the elements of another
@@ -90,7 +90,7 @@ module internal List =
                     let other, rest = partitionUntil (f >> not) other
                     yield last, other
                     yield! loop rest
-                | [] when other = [] -> ()
+                | [] when List.isEmpty other -> ()
                 | _ -> invalidArg "" "Should start with true"
             }
 

src/Common/StringParsing.fs

@@ -15,8 +15,12 @@ open FSharp.Formatting.Markdown
 
 module String =
     /// Matches when a string is a whitespace or null
+    [<return: Struct>]
     let (|WhiteSpace|_|) (s) =
-        if String.IsNullOrWhiteSpace(s) then Some() else None
+        if String.IsNullOrWhiteSpace(s) then
+            ValueSome()
+        else
+            ValueNone
 
     /// Returns a string trimmed from both start and end
     let (|TrimBoth|) (text: string) = text.Trim()
@@ -117,15 +121,20 @@ module String =
 
 module StringPosition =
     /// Matches when a string is a whitespace or null
+    [<return: Struct>]
     let (|WhiteSpace|_|) (s, _n: MarkdownRange) =
-        if String.IsNullOrWhiteSpace(s) then Some() else None
+        if String.IsNullOrWhiteSpace(s) then
+            ValueSome()
+        else
+            ValueNone
 
     /// Matches when a string does starts with non-whitespace
+    [<return: Struct>]
     let (|Unindented|_|) (s: string, _n: MarkdownRange) =
         if not (String.IsNullOrWhiteSpace(s)) && s.TrimStart() = s then
-            Some()
+            ValueSome()
         else
-            None
+            ValueNone
 
     /// Returns a string trimmed from both start and end
     let (|TrimBoth|) (text: string, n: MarkdownRange) =
@@ -174,11 +183,12 @@ module StringPosition =
              StartColumn = n.StartColumn + text.Length - trimmed.Length })
 
     /// Matches when a string starts with any of the specified sub-strings
+    [<return: Struct>]
     let (|StartsWithAny|_|) (starts: string seq) (text: string, _n: MarkdownRange) =
         if starts |> Seq.exists (fun s -> text.StartsWith(s, StringComparison.Ordinal)) then
-            Some()
+            ValueSome()
         else
-            None
+            ValueNone
 
     /// Matches when a string starts with the specified sub-string
     let (|StartsWith|_|) (start: string) (text: string, n: MarkdownRange) =
@@ -297,15 +307,16 @@ module StringPosition =
 
     /// Matches when a string consists of some number of
     /// complete repetitions of a specified sub-string.
+    [<return: Struct>]
     let (|EqualsRepeated|_|) (repeated, _n: MarkdownRange) =
         function
-        | StartsWithRepeated repeated (_n, (v, _)) when (String.IsNullOrWhiteSpace v) -> Some()
-        | _ -> None
+        | StartsWithRepeated repeated (_n, (v, _)) when (String.IsNullOrWhiteSpace v) -> ValueSome()
+        | _ -> ValueNone
 
 module List =
     /// Matches a list if it starts with a sub-list that is delimited
     /// using the specified delimiters. Returns a wrapped list and the rest.
-    let inline (|DelimitedWith|_|) startl endl input =
+    let inline internal (|DelimitedWith|_|) startl endl input =
         if List.startsWith startl input then
             match List.partitionUntilEquals endl (List.skip startl.Length input) with
             | Some(pre, post) -> Some(pre, List.skip endl.Length post, startl.Length, endl.Length)
@@ -314,14 +325,14 @@ module List =
             None
 
     /// Matches a list if it starts with a sub-list. Returns the list.
-    let inline (|StartsWith|_|) startl input =
+    let inline internal (|StartsWith|_|) startl input =
         if List.startsWith startl input then Some input else None
 
     /// Matches a list if it starts with a sub-list that is delimited
     /// using the specified delimiter. Returns a wrapped list and the rest.
-    let inline (|Delimited|_|) str = (|DelimitedWith|_|) str str
+    let inline internal (|Delimited|_|) str = (|DelimitedWith|_|) str str
 
-    let inline (|DelimitedNTimes|_|) str input =
+    let inline internal (|DelimitedNTimes|_|) str input =
         let strs, _items = List.partitionWhile (fun i -> i = str) input
 
         match strs with
@@ -403,9 +414,8 @@ module Lines =
     let (|TrimParagraphLines|) lines =
         lines
         // first remove all whitespace on the beginning of the line
-        |> List.map (fun (StringPosition.TrimStart s) -> s)
-        // Now remove all additional spaces at the end, but keep two spaces if existent
-        |> List.map (fun (s, n) ->
+        // then remove all additional spaces at the end, but keep two spaces if existent
+        |> List.map (fun (StringPosition.TrimStart(s, n)) ->
             let endsWithTwoSpaces = s.EndsWith("  ", StringComparison.Ordinal)
 
             let trimmed = s.TrimEnd([| ' ' |]) + if endsWithTwoSpaces then "  " else ""

src/FSharp.Formatting.ApiDocs/Categorise.fs

@@ -59,9 +59,9 @@ let entities (nsIndex: int, ns: ApiDocNamespace, suppress) =
                       //
                       // See https://github.com/fsharp/fsharp-core-docs/issues/57, we may rethink this
                       |> List.filter (fun e ->
-                          not (e.Symbol.Namespace = Some "Microsoft.FSharp.Data.UnitSystems.SI.UnitSymbols"))
+                          (e.Symbol.Namespace <> Some "Microsoft.FSharp.Data.UnitSystems.SI.UnitSymbols"))
                       |> List.filter (fun e ->
-                          not (e.Symbol.Namespace = Some "Microsoft.FSharp.Data.UnitSystems.SI.UnitNames"))
+                          (e.Symbol.Namespace <> Some "Microsoft.FSharp.Data.UnitSystems.SI.UnitNames"))
                       // Don't show 'AnonymousObject' in list-of-namespaces navigation
                       |> List.filter (fun e ->
                           not (

src/FSharp.Formatting.ApiDocs/GenerateModel.fs

@@ -62,15 +62,16 @@ module internal Utils =
         else
             None
 
+    [<return: Struct>]
     let (|MeasureOne|_|) (typ: FSharpType) =
         if
             typ.HasTypeDefinition
             && typ.TypeDefinition.LogicalName = "1"
             && typ.GenericArguments.Count = 0
         then
-            Some()
+            ValueSome()
         else
-            None
+            ValueNone
 
     let tryGetLocation (symbol: FSharpSymbol) =
         match symbol.ImplementationLocation with
@@ -105,7 +106,7 @@ module internal Utils =
         member x.TryAttr(attr: string) =
             let a = x.Attribute(XName.Get attr)
 
-            if a = null then None
+            if isNull a then None
             else if String.IsNullOrEmpty a.Value then None
             else Some a.Value
 
@@ -1757,7 +1758,7 @@ module internal SymbolReader =
             [ let mutable line = ""
 
               while (line <- reader.ReadLine()
-                     line <> null) do
+                     not (isNull line)) do
                   yield line ]
 
         String.removeSpaces lines
@@ -1905,14 +1906,14 @@ module internal SymbolReader =
                     let name = elem.Attribute(XName.Get "name")
                     let nameAsHtml = HttpUtility.HtmlEncode name.Value
 
-                    if name <> null then
+                    if not (isNull name) then
                         html.AppendFormat("<span class=\"fsdocs-param-name\">{0}</span>", nameAsHtml)
                         |> ignore
                 | "see"
                 | "seealso" ->
                     let cref = elem.Attribute(XName.Get "cref")
 
-                    if cref <> null then
+                    if not (isNull cref) then
                         if System.String.IsNullOrEmpty(cref.Value) || cref.Value.Length < 3 then
                             printfn "ignoring invalid cref specified in: %A" e
 
@@ -2018,7 +2019,7 @@ module internal SymbolReader =
         let remarks =
             let remarkNodes = doc.Elements(XName.Get "remarks") |> Seq.toList
 
-            if List.length remarkNodes > 0 then
+            if not (List.isEmpty remarkNodes) then
                 let html = new StringBuilder()
 
                 for (id, e) in List.indexed remarkNodes do
@@ -2053,7 +2054,7 @@ module internal SymbolReader =
             [ for e in exceptionNodes do
                   let cref = e.Attribute(XName.Get "cref")
 
-                  if cref <> null then
+                  if not (isNull cref) then
                       if String.IsNullOrEmpty(cref.Value) || cref.Value.Length < 3 then
                           printfn "Warning: Invalid cref specified in: %A" doc
 
@@ -2581,7 +2582,7 @@ module internal SymbolReader =
         |> Seq.choose (fun p ->
             let nameAttr = p.Attribute(XName.Get "name")
 
-            if nameAttr = null then
+            if isNull nameAttr then
                 None
             else
                 Some(nameAttr.Value, p.Value))
@@ -2821,7 +2822,7 @@ module internal SymbolReader =
             [ for e in doc.Descendants(XName.Get "member") do
                   let attr = e.Attribute(XName.Get "name")
 
-                  if attr <> null && not (String.IsNullOrEmpty(attr.Value)) then
+                  if (not (isNull attr)) && not (String.IsNullOrEmpty(attr.Value)) then
                       yield attr.Value, e ] do
             // NOTE: We completely ignore duplicate keys and I don't see
             // an easy way to detect where "value" is coming from, because the entries

src/FSharp.Formatting.CodeFormat/CodeFormatAgent.fs

@@ -352,7 +352,7 @@ module CodeFormatter =
                 [| let line = ref ""
 
                    while (line := reader.ReadLine()
-                          line.Value <> null) do
+                          not (isNull line.Value)) do
                        yield line.Value |]
             // Get options for a standalone script file (this adds some
             // default references and doesn't require full project information)

src/FSharp.Formatting.CodeFormat/SourceCode.fs

@@ -20,7 +20,7 @@ type ToolTipSpan =
     | HardLineBreak
 
 /// Classifies tokens reported by the FCS
-[<RequireQualifiedAccess>]
+[<RequireQualifiedAccess; Struct>]
 type TokenKind =
     | Keyword
     | String
@@ -49,7 +49,7 @@ type TokenKind =
 
 
 /// Represents a kind of error reported from the F# compiler (warning or error)
-[<RequireQualifiedAccess>]
+[<RequireQualifiedAccess; Struct>]
 type ErrorKind =
     | Error
     | Warning

src/FSharp.Formatting.Common/PynbModel.fs

@@ -88,8 +88,7 @@ type Cell =
                       | Some(x) -> string<int> x)
                      (this.outputs |> Array.map string<Output> |> String.concat ",\n")))
             (this.source
-             |> Array.map addLineEnd
-             |> Array.map escapeAndQuote
+             |> Array.map (addLineEnd >> escapeAndQuote)
              |> String.concat ",\n    ")
 
 type Kernelspec =

src/FSharp.Formatting.Common/Templating.fs

@@ -280,14 +280,12 @@ module internal SimpleTemplating =
             // If there is no template or the template is an empty file, return just document + tooltips (tooltips empty if not HTML)
             let lookup = readOnlyDict substitutions
 
-            (if lookup.ContainsKey ParamKeys.``fsdocs-content`` then
-                 lookup.[ParamKeys.``fsdocs-content``]
-             else
-                 "")
-            + (if lookup.ContainsKey ParamKeys.``fsdocs-tooltips`` then
-                   "\n\n" + lookup.[ParamKeys.``fsdocs-tooltips``]
-               else
-                   "")
+            (match lookup.TryGetValue ParamKeys.``fsdocs-content`` with
+             | true, lookupContent -> lookupContent
+             | false, _ -> "")
+            + (match lookup.TryGetValue ParamKeys.``fsdocs-tooltips`` with
+               | true, lookupTips -> "\n\n" + lookupTips
+               | false, _ -> "")
         | Some templateText -> ApplySubstitutionsInText substitutions templateText
 
     let UseFileAsSimpleTemplate (substitutions, templateOpt, outputFile) =

src/FSharp.Formatting.Common/YaafFSharpScripting.fs

@@ -246,10 +246,9 @@ module internal CompilerServiceExtensions =
             dllFiles
             |> List.map (fun file ->
                 file,
-                (if referenceDict.ContainsKey file then
-                     Some referenceDict.[file]
-                 else
-                     None))
+                (match referenceDict.TryGetValue file with
+                 | true, refFile -> Some refFile
+                 | false, _ -> None))
 
         let getProjectReferencesSimple frameworkVersion (dllFiles: string list) =
             getProjectReferences frameworkVersion None None dllFiles |> resolve dllFiles
@@ -464,26 +463,29 @@ module internal ArgParser =
         else
             None
 
+    [<return: Struct>]
     let (|FsiBoolArg|_|) argName s =
         match s with
         | StartsWith argName rest ->
             if String.IsNullOrWhiteSpace rest then
-                Some true
+                ValueSome true
             else
                 match rest with
-                | "+" -> Some true
-                | "-" -> Some false
-                | _ -> None
-        | _ -> None
+                | "+" -> ValueSome true
+                | "-" -> ValueSome false
+                | _ -> ValueNone
+        | _ -> ValueNone
 
 open ArgParser
 
+[<Struct>]
 type internal DebugMode =
     | Full
     | PdbOnly
     | Portable
     | NoDebug
 
+[<Struct>]
 type internal OptimizationType =
     | NoJitOptimize
     | NoJitTracking
@@ -761,7 +763,7 @@ type internal FsiOptions =
                | [] -> Seq.empty
                | opts ->
                    opts
-                   |> Seq.map (fun (enable, types) ->
+                   |> Seq.collect (fun (enable, types) ->
                        seq {
                            yield sprintf "--optimize%s" (getMinusPlus enable)
 
@@ -778,7 +780,6 @@ type internal FsiOptions =
                                        | NoTailCalls -> "notailcalls")
                                    |> String.concat ","
                        })
-                   |> Seq.concat
 
            yield! getSimpleBoolArg "--quiet" x.Quiet
            yield! getSimpleBoolArg "--quotations-debug" x.QuotationsDebug

src/FSharp.Formatting.Literate/Contexts.fs

@@ -23,7 +23,7 @@ type internal CompilerContext =
     }
 
 /// Defines the possible output types from literate script (HTML, Latex, Pynb)
-[<RequireQualifiedAccess>]
+[<RequireQualifiedAccess; Struct>]
 type OutputKind =
     /// Requests HTML output
     | Html

src/FSharp.Formatting.Literate/Evaluator.fs

@@ -15,7 +15,7 @@ open FSharp.Formatting.Internal
 /// <namespacedoc>
 ///   <summary>Functionality to support literate evaluation for F# scripts</summary>
 /// </namespacedoc>
-[<RequireQualifiedAccessAttribute>]
+[<RequireQualifiedAccessAttribute; Struct>]
 type FsiEmbedKind =
     /// The FSI output
     | FsiOutput

src/FSharp.Formatting.Literate/ParseScript.fs

@@ -163,7 +163,9 @@ type internal ParseScript(parseOptions, ctx: CompilerContext) =
         | Command "condition" name when not (String.IsNullOrWhiteSpace name) -> { Condition = Some name }
         | _ -> { Condition = None }
 
-    let (|EmptyString|_|) (v: string) = if v.Length = 0 then Some() else None
+    [<return: Struct>]
+    let (|EmptyString|_|) (v: string) =
+        if v.Length = 0 then ValueSome() else ValueNone
 
     /// Transform list of code blocks (snippet/comment/command)
     /// into a formatted Markdown document, with link definitions
@@ -386,7 +388,7 @@ type internal ParseScript(parseOptions, ctx: CompilerContext) =
 
         let parsedBlocks =
             [ for Snippet(name, lines) in sourceSnippets do
-                  if name <> null then
+                  if not (isNull name) then
                       yield BlockComment("## " + name)
 
                   yield! parseScriptFile (lines) ]