Consider selection range when collecting trivia.

src/Fantomas.Core.Tests/FormatAstTests.fs

@@ -13,7 +13,7 @@ let parseAndFormat fn sourceCode =
         |> fst
 
     let formattedCode =
-        CodeFormatter.FormatASTAsync(ast, [], fn sourceCode, config)
+        CodeFormatter.FormatASTAsync(ast, fn sourceCode, config)
         |> Async.RunSynchronously
         |> String.normalizeNewLine
         |> fun s -> s.TrimEnd('\n')

src/Fantomas.Core.Tests/FormattingSelectionOnlyTests.fs

@@ -111,9 +111,9 @@ functionApplication
 let ``only format trivia inside the selection`` () =
     formatSelectionOnly
         false
-        (mkSelection (5, 0) (6, 20))
+        (mkSelection (5, 0) (6, 10))
         """
-
+let x = 0
 
 
 

src/Fantomas.Core.Tests/SynLongIdentTests.fs

@@ -397,7 +397,6 @@ let ``backticks can be added from AST only scenarios`` () =
 
     CodeFormatter.FormatASTAsync(
         tree,
-        [],
         None,
         { config with
             StrictMode = true

src/Fantomas.Core.Tests/TestHelpers.fs

@@ -7,8 +7,6 @@ open NUnit.Framework
 open FsCheck
 open FsUnit
 open FSharp.Compiler.Text
-open FSharp.Compiler.Syntax
-open FSharp.Compiler.Xml
 open Fantomas.Core.FormatConfig
 open Fantomas.Core
 
@@ -45,11 +43,12 @@ let formatSourceStringWithDefines defines (s: string) config =
             let source = CodeFormatterImpl.getSourceText s
             let! asts = CodeFormatterImpl.parse false source
 
-            let ast, defineCombination =
+            let ast =
                 Array.filter (fun (_, d: DefineCombination) -> List.sort d = List.sort defines) asts
                 |> Array.head
+                |> fst
 
-            return CodeFormatterImpl.formatWith (Some source) defineCombination ast config
+            return CodeFormatterImpl.formatWith (Some source) ast config None
         }
         |> Async.RunSynchronously
 
@@ -67,7 +66,7 @@ let isValidFSharpCode isFsiFile s =
     |> Async.RunSynchronously
 
 let formatAST a s c =
-    CodeFormatter.FormatASTAsync(a, [], s, c)
+    CodeFormatter.FormatASTAsync(a, s, c)
     |> Async.RunSynchronously
 
 let equal x =

src/Fantomas.Core.Tests/TriviaTests.fs

@@ -10,7 +10,7 @@ open Fantomas.Core.FormatConfig
 let private toTrivia source =
     let sourceText = CodeFormatterImpl.getSourceText source
     let ast, _ = Fantomas.FCS.Parse.parseFile false sourceText []
-    Trivia.collectTrivia FormatConfig.Default sourceText ast
+    Trivia.collectTrivia FormatConfig.Default sourceText ast None
 
 let private toTriviaWithDefines source =
     let sourceText = CodeFormatterImpl.getSourceText source
@@ -24,7 +24,7 @@ let private toTriviaWithDefines source =
     let defineCombinations = Defines.getDefineCombination hashDirectives
 
     defineCombinations
-    |> List.map (fun dc -> dc, Trivia.collectTrivia FormatConfig.Default sourceText ast)
+    |> List.map (fun dc -> dc, Trivia.collectTrivia FormatConfig.Default sourceText ast None)
     |> Map.ofList
 
 [<Test>]

src/Fantomas.Core/CodeFormatter.fs

@@ -5,18 +5,13 @@ open FSharp.Compiler.Syntax
 [<Sealed>]
 type CodeFormatter =
     static member ParseAsync(isSignature, source) : Async<(ParsedInput * string list) array> =
-        async {
-            let! asts =
-                CodeFormatterImpl.getSourceText source
-                |> CodeFormatterImpl.parse isSignature
-
-            return asts
-        }
+        CodeFormatterImpl.getSourceText source
+        |> CodeFormatterImpl.parse isSignature
 
-    static member FormatASTAsync(ast: ParsedInput, defines: string list, source, config) : Async<string> =
+    static member FormatASTAsync(ast: ParsedInput, source, config) : Async<string> =
         let sourceAndTokens = Option.map CodeFormatterImpl.getSourceText source
 
-        CodeFormatterImpl.formatAST ast defines sourceAndTokens config
+        CodeFormatterImpl.formatAST ast sourceAndTokens config None
         |> async.Return
 
     static member FormatDocumentAsync(isSignature, source, config) =

src/Fantomas.Core/CodeFormatter.fsi

@@ -10,8 +10,7 @@ type CodeFormatter =
     static member ParseAsync: isSignature: bool * source: string -> Async<(ParsedInput * string list) array>
 
     /// Format an abstract syntax tree using an optional source for trivia processing
-    static member FormatASTAsync:
-        ast: ParsedInput * defines: string list * source: string option * config: FormatConfig -> Async<string>
+    static member FormatASTAsync: ast: ParsedInput * source: string option * config: FormatConfig -> Async<string>
 
     /// Format a source string using given config
     static member FormatDocumentAsync: isSignature: bool * source: string * config: FormatConfig -> Async<string>

src/Fantomas.Core/CodeFormatterImpl.fs

@@ -54,9 +54,14 @@ let parse (isSignature: bool) (source: ISourceText) : Async<(ParsedInput * Defin
             })
         |> Async.Parallel
 
-let formatWith (sourceText: ISourceText option) (defineCombination: DefineCombination) ast config =
+let formatWith
+    (sourceText: ISourceText option)
+    (ast: ParsedInput)
+    (config: FormatConfig)
+    (selection: range option)
+    : string =
     let formattedSourceCode =
-        let context = Context.Context.Create config sourceText defineCombination ast
+        let context = Context.Context.Create config sourceText ast selection
 
         context
         |> genParsedInput ASTContext.Default ast
@@ -72,7 +77,7 @@ let format (config: FormatConfig) (isSignature: bool) (source: ISourceText) : As
             asts
             |> Array.map (fun (ast', defineCombination) ->
                 async {
-                    let formattedCode = formatWith (Some source) defineCombination ast' config
+                    let formattedCode = formatWith (Some source) ast' config None
                     return (defineCombination, formattedCode)
                 })
             |> Async.Parallel
@@ -117,5 +122,5 @@ Please raise an issue at https://fsprojects.github.io/fantomas-tools/#/fantomas/
 let formatDocument config isSignature source = format config isSignature source
 
 /// Format an abstract syntax tree using given config
-let formatAST ast defines sourceText config =
-    formatWith sourceText defines ast config
+let formatAST ast sourceText config selection =
+    formatWith sourceText ast config selection

src/Fantomas.Core/Context.fs

@@ -199,10 +199,10 @@ type internal Context =
           FileName = String.Empty
           SourceText = None }
 
-    static member Create config (source: ISourceText option) (defineCombination: DefineCombination) (ast: ParsedInput) =
+    static member Create config (source: ISourceText option) (ast: ParsedInput) (selection: range option) =
         let trivia, sourceText =
             match source with
-            | Some source when not config.StrictMode -> Trivia.collectTrivia config source ast, Some source
+            | Some source when not config.StrictMode -> Trivia.collectTrivia config source ast selection, Some source
             | _ -> [], None
 
         let triviaByNodes =

src/Fantomas.Core/Selection.fs

@@ -150,7 +150,7 @@ let formatSelection
                         MaxLineLength = maxLineLength }
 
                 let selection =
-                    CodeFormatterImpl.formatAST tree [] (Some sourceText) selectionConfig
+                    CodeFormatterImpl.formatAST tree (Some sourceText) selectionConfig (Some selection)
 
                 return Some(selection.TrimEnd([| '\r'; '\n' |]))
     }

src/Fantomas.Core/Trivia.fs

@@ -207,6 +207,7 @@ let private addTriviaToTriviaNode (startOfSourceCode: int) (triviaNodes: TriviaN
 let internal collectTriviaFromDirectives
     (source: ISourceText)
     (directives: ConditionalDirectiveTrivia list)
+    (selection: range option)
     : Trivia list =
     directives
     |> List.map (function
@@ -216,8 +217,16 @@ let internal collectTriviaFromDirectives
 
         | ConditionalDirectiveTrivia.Else r -> { Item = Directive "#else"; Range = r }
         | ConditionalDirectiveTrivia.EndIf r -> { Item = Directive "#endif"; Range = r })
+    |> fun trivia ->
+        match selection with
+        | None -> trivia
+        | Some selection -> List.filter (fun t -> RangeHelpers.rangeContainsRange selection t.Range) trivia
 
-let internal collectTriviaFromCodeComments (source: ISourceText) (codeComments: CommentTrivia list) : Trivia list =
+let internal collectTriviaFromCodeComments
+    (source: ISourceText)
+    (codeComments: CommentTrivia list)
+    (selection: range option)
+    : Trivia list =
     codeComments
     |> List.map (function
         | CommentTrivia.BlockComment r ->
@@ -236,6 +245,10 @@ let internal collectTriviaFromCodeComments (source: ISourceText) (codeComments:
                 )
 
             { Item = item; Range = r })
+    |> fun trivia ->
+        match selection with
+        | None -> trivia
+        | Some selection -> List.filter (fun t -> RangeHelpers.rangeContainsRange selection t.Range) trivia
 
 // TODO: optimize the range of which newlines are allowed in
 // for a selection, the newlines should be found inside the selection
@@ -247,6 +260,7 @@ let internal collectTriviaFromBlankLines
     (source: ISourceText)
     (triviaNode: TriviaNodeAssigner)
     (codeComments: CommentTrivia list)
+    (codeRange: range)
     : Trivia list =
     let fileIndex = triviaNode.Range.FileIndex
 
@@ -290,9 +304,10 @@ let internal collectTriviaFromBlankLines
             }
         )
 
-    let max = source.GetLineCount() - 1
+    let min = codeRange.StartLine - 1
+    let max = codeRange.EndLine - 1
 
-    (0, [ 0..max ])
+    (min, [ min..max ])
     ||> List.chooseState (fun count idx ->
         if ignoreLines.Contains(idx + 1) then
             0, None
@@ -317,7 +332,12 @@ let internal collectTriviaFromBlankLines
     3. Merge trivia with triviaNodes
     4. genTrivia should use ranges to identify what extra content should be added from what triviaNode
 *)
-let collectTrivia (config: FormatConfig) (source: ISourceText) (ast: ParsedInput) : TriviaNode list =
+let collectTrivia
+    (config: FormatConfig)
+    (source: ISourceText)
+    (ast: ParsedInput)
+    (selection: range option)
+    : TriviaNode list =
     let triviaNodesFromAST, directives, codeComments =
         match ast with
         | ParsedInput.ImplFile (ParsedImplFileInput (hds, mns, directives, codeComments)) ->
@@ -326,9 +346,15 @@ let collectTrivia (config: FormatConfig) (source: ISourceText) (ast: ParsedInput
             sigAstToNode ast.FullRange mns, directives, codeComments
 
     let trivia =
-        [ yield! collectTriviaFromDirectives source directives
-          yield! collectTriviaFromCodeComments source codeComments
-          yield! collectTriviaFromBlankLines config source triviaNodesFromAST codeComments ]
+        [ yield! collectTriviaFromDirectives source directives selection
+          yield! collectTriviaFromCodeComments source codeComments selection
+          yield!
+              collectTriviaFromBlankLines
+                  config
+                  source
+                  triviaNodesFromAST
+                  codeComments
+                  (Option.defaultValue ast.FullRange selection) ]
         |> List.sortBy (fun n -> n.Range.Start.Line, n.Range.Start.Column)
 
     // TODO: do we still need this?

src/Fantomas.Core/TriviaHelpers.fs

@@ -5,10 +5,6 @@ open Fantomas.Core.TriviaTypes
 
 [<RequireQualifiedAccess>]
 module internal TriviaHelpers =
-    let findInRange (trivia: TriviaNode list) (range: Range) =
-        trivia
-        |> List.tryFind (fun t -> RangeHelpers.rangeContainsRange range t.Range)
-
     let ``has content after after that matches``
         (findTrivia: TriviaNode -> bool)
         (contentAfter: TriviaContent -> bool)