Respect column info for single line comments

Fixes fsprojects#1233

src/Fantomas.Tests/CommentTests.fs

@@ -231,8 +231,8 @@ let f() =
     |> should
         equal
         """
-/// XML COMMENT A
-// Other comment
+   /// XML COMMENT A
+     // Other comment
 let f () =
     // COMMENT A
     let y = 1
@@ -398,9 +398,9 @@ let ``should keep comments on else if`` () =
         """
 if a then ()
 else
-    // Comment 1
+// Comment 1
     if b then ()
-    // Comment 2
+// Comment 2
     else ()
 """
         config
@@ -1250,7 +1250,7 @@ let a = 8
         equal
         """
 let a = 8
-// foobar
+  // foobar
 """
 
 [<Test>]
@@ -1559,6 +1559,55 @@ Host
 //
 """
 
+[<Test>]
+let ``should not move the starting point of a single-line comment, 1233`` () =
+    formatSourceString
+        false
+        """
+type CustomCancelSource() =
+    interface IDisposable with
+        member self.Dispose() =
+            try
+                self.Cancel()
+            with
+            | :? ObjectDisposedException ->
+                ()
+            // TODO: cleanup also subscribed handlers? see https://stackoverflow.com/q/58912910/544947
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+type CustomCancelSource() =
+    interface IDisposable with
+        member self.Dispose() =
+            try
+                self.Cancel()
+            with
+            | :? ObjectDisposedException -> ()
+            // TODO: cleanup also subscribed handlers? see https://stackoverflow.com/q/58912910/544947
+"""
+
+[<Test>]
+let ``should not move the starting point of a single-line comment (2), 1233`` () =
+    formatSourceString
+        false
+        """
+let foo a =
+    someLongFunctionCall parameterOne parameterTwo parameterThree
+    // bar
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+let foo a =
+    someLongFunctionCall parameterOne parameterTwo parameterThree
+    // bar
+"""
+
 [<Test>]
 let ``comment after bracket in record should not be duplicated in computation expression, 1912`` () =
     formatSourceString
@@ -1598,4 +1647,4 @@ type TorDirectory =
                 // comment
                 }
         }
-"""
+"""

src/Fantomas.Tests/ComputationExpressionTests.fs

@@ -2309,7 +2309,7 @@ let ``keep new line before match bang, 1313`` () =
     |> should
         equal
         """
-/// a codefix that generates union cases for an incomplete match expression
+  /// a codefix that generates union cases for an incomplete match expression
 let generateUnionCases =
     ifDiagnosticByMessage
         (fun diagnostic codeActionParams ->

src/Fantomas.Tests/ControlStructureTests.fs

@@ -724,7 +724,7 @@ let ``keep new line before for loop, 1317`` () =
     |> should
         equal
         """
-/// Fold over the array passing the index and element at that index to a folding function
+  /// Fold over the array passing the index and element at that index to a folding function
 let foldi (folder: 'State -> int -> 'T -> 'State) (state: 'State) (array: 'T []) =
     checkNonNull "array" array
 

src/Fantomas.Tests/ElmishTests.fs

@@ -1456,6 +1456,6 @@ a [] [
         equal
         """
 a [] [
-// def
+    // def
 ]
 """

src/Fantomas.Tests/ModuleTests.fs

@@ -39,9 +39,9 @@ let ``open modules`` () =
     |> should
         equal
         """
-// comment1
+    // comment1
 open System.IO
-// comment2
+    // comment2
 open System
 """
 

src/Fantomas.Tests/OperatorTests.fs

@@ -952,7 +952,7 @@ let ``add in keyword when let binding is part of single infix expression`` () =
     |> should
         equal
         """
-// Check for the [<ProjectionParameter>] attribute on an argument position
+    // Check for the [<ProjectionParameter>] attribute on an argument position
 let isCustomOperationProjectionParameter i (nm: Ident) =
     match tryGetArgInfosForCustomOperator nm with
     | None -> false

src/Fantomas.Tests/TokenParserTests.fs

@@ -220,7 +220,7 @@ let a = 9
 // foo"""
 
     match triviaNodes with
-    | { Item = Comment (LineCommentOnSingleLine l1) } :: _ -> String.normalizeNewLine l1 == expectedComment
+    | { Item = Comment (LineCommentOnSingleLine (l1, _)) } :: _ -> String.normalizeNewLine l1 == expectedComment
     | _ -> failwith "Expected two line comments"
 
 [<Test>]

src/Fantomas.Tests/TriviaTests.fs

@@ -46,7 +46,7 @@ let a = 9
     let triviaNodes = toTrivia source |> List.head
 
     match triviaNodes with
-    | [ { ContentBefore = [ Comment (LineCommentOnSingleLine lineComment) ] } ] -> lineComment == "// meh"
+    | [ { ContentBefore = [ Comment (LineCommentOnSingleLine (lineComment, _)) ] } ] -> lineComment == "// meh"
     | _ -> failwith "Expected line comment"
 
 [<Test>]
@@ -59,7 +59,7 @@ let a = 'c'
     let triviaNodes = toTrivia source |> List.head
 
     match triviaNodes with
-    | [ { ContentBefore = [ Comment (LineCommentOnSingleLine lineComment) ] } ] -> lineComment == "// foo"
+    | [ { ContentBefore = [ Comment (LineCommentOnSingleLine (lineComment, _)) ] } ] -> lineComment == "// foo"
     | _ -> failwith "Expected line comment"
 
 [<Test>]
@@ -101,7 +101,7 @@ let a = 7
 // bar"""
 
     match triviaNodes with
-    | [ { ContentBefore = [ Comment (LineCommentOnSingleLine comments) ] } ] ->
+    | [ { ContentBefore = [ Comment (LineCommentOnSingleLine (comments, _)) ] } ] ->
         String.normalizeNewLine comments
         == expectedComment
     | _ -> fail ()
@@ -133,7 +133,7 @@ let ``comment after all source code`` () =
 
     match triviaNodes with
     | [ { Type = MainNode mn
-          ContentAfter = [ Comment (LineCommentOnSingleLine lineComment) ] } ] ->
+          ContentAfter = [ Comment (LineCommentOnSingleLine (lineComment, _)) ] } ] ->
         mn == SynModuleDecl_Types
 
         lineComment
@@ -261,7 +261,7 @@ let a =  b + c
     let triviaNodes = toTrivia source |> List.head
 
     match triviaNodes with
-    | [ { ContentBefore = [ Comment (LineCommentOnSingleLine comment) ] } ] -> comment == "// (* meh *)"
+    | [ { ContentBefore = [ Comment (LineCommentOnSingleLine (comment, _)) ] } ] -> comment == "// (* meh *)"
     | _ -> failwith "Expected line comment"
 
 [<Test>]
@@ -506,7 +506,7 @@ type LongIdentWithDots =
 /// LongIdent can be empty list - it is used to denote that name of some AST element is absent (i.e. empty type name in inherit)"""
 
     match trivia with
-    | [ { ContentBefore = [ Comment (LineCommentOnSingleLine comment) ] } ] ->
+    | [ { ContentBefore = [ Comment (LineCommentOnSingleLine (comment, _)) ] } ] ->
         String.normalizeNewLine comment == expectedComment
     | _ -> fail ()
 

src/Fantomas.Tests/TupleTests.fs

@@ -323,6 +323,6 @@ func (
     0, // def
     // ghi
     1 // jkl
-// mno
+        // mno
 )
 """

src/Fantomas/Context.fs

@@ -1176,6 +1176,11 @@ let internal printTriviaContent (c: TriviaContent) (ctx: Context) =
         -- s
         +> sepSpace
         +> ifElse after sepNlnForTrivia sepNone
+    | Comment (LineCommentOnSingleLine (s, commentRange)) ->
+        (ifElse addNewline sepNlnForTrivia sepNone)
+        +> ifElse (ctx.WriterModel.Indent = 0) (rep commentRange.StartColumn !- " ") sepNone
+        +> !-s
+        +> sepNlnForTrivia
     | Newline -> (ifElse addNewline (sepNlnForTrivia +> sepNlnForTrivia) sepNlnForTrivia)
     | Keyword _
     | Number _
@@ -1185,8 +1190,7 @@ let internal printTriviaContent (c: TriviaContent) (ctx: Context) =
     | CharContent _
     | EmbeddedIL _
     | KeywordString _ -> sepNone // don't print here but somewhere in CodePrinter
-    | Directive s
-    | Comment (LineCommentOnSingleLine s) ->
+    | Directive s ->
         (ifElse addNewline sepNlnForTrivia sepNone)
         +> !-s
         +> sepNlnForTrivia

src/Fantomas/TokenParser.fs

@@ -885,16 +885,16 @@ let rec private getTriviaFromTokensThemSelves
                                 commentTokens
                                 |> List.skip afterSourceTokens.Length
 
-                            let triviaContent =
-                                collectComment commentTokens
-                                |> LineCommentOnSingleLine
-                                |> Comment
-
                             let range =
                                 let headToken = List.head commentTokens
                                 let lastToken = List.tryLast commentTokens
                                 getRangeBetween mkRange headToken (Option.defaultValue headToken lastToken)
 
+                            let triviaContent =
+                                (collectComment commentTokens, range)
+                                |> LineCommentOnSingleLine
+                                |> Comment
+
                             Trivia.Create triviaContent range |> Some
                         else
                             None
@@ -906,16 +906,16 @@ let rec private getTriviaFromTokensThemSelves
                     // We should not hit this branch
                     foundTrivia
             else
-                let triviaContent =
-                    collectComment commentTokens
-                    |> LineCommentOnSingleLine
-                    |> Comment
-
                 let range =
                     let headToken = List.head commentTokens
                     let lastToken = List.tryLast commentTokens
                     getRangeBetween mkRange headToken (Option.defaultValue headToken lastToken)
 
+                let triviaContent =
+                    (collectComment commentTokens, range)
+                    |> LineCommentOnSingleLine
+                    |> Comment
+
                 (Trivia.Create triviaContent range :: foundTrivia)
 
         getTriviaFromTokensThemSelves mkRange lastButOneNonWhiteSpaceToken lastNonWhiteSpaceToken rest info

src/Fantomas/Trivia.fs

@@ -272,22 +272,30 @@ let private addTriviaToTriviaNode
     trivia
     =
     match trivia with
-    | { Item = Comment (LineCommentOnSingleLine _ as comment)
+    | { Item = Comment (LineCommentOnSingleLine (comment, _))
         Range = range } ->
         match triviaBetweenAttributeAndParentBinding triviaNodes range.StartLine with
-        | Some _ as node -> updateTriviaNode (fun tn -> tn.ContentAfter.Add(Comment(comment))) triviaNodes node
+        | Some _ as node ->
+            updateTriviaNode
+                (fun tn -> tn.ContentAfter.Add(Comment(LineCommentOnSingleLine(comment, range))))
+                triviaNodes
+                node
         | None ->
             let nodeAfterLine =
                 findFirstNodeAfterLine triviaNodes range.StartLine
 
             match nodeAfterLine with
             | Some _ ->
                 nodeAfterLine
-                |> updateTriviaNode (fun tn -> tn.ContentBefore.Add(Comment(comment))) triviaNodes
+                |> updateTriviaNode
+                    (fun tn -> tn.ContentBefore.Add(Comment(LineCommentOnSingleLine(comment, range))))
+                    triviaNodes
             | None ->
                 // try and find a node above
                 findNodeBeforeLineFromStart triviaNodes range.StartLine
-                |> updateTriviaNode (fun tn -> tn.ContentAfter.Add(Comment(comment))) triviaNodes
+                |> updateTriviaNode
+                    (fun tn -> tn.ContentAfter.Add(Comment(LineCommentOnSingleLine(comment, range))))
+                    triviaNodes
 
     | { Item = Comment (BlockComment (comment, _, _))
         Range = range } ->

src/Fantomas/TriviaTypes.fs

@@ -61,7 +61,7 @@ type Token =
 
 type Comment =
     | LineCommentAfterSourceCode of comment: string
-    | LineCommentOnSingleLine of comment: string
+    | LineCommentOnSingleLine of comment: string * range
     | BlockComment of string * newlineBefore: bool * newlineAfter: bool
 
 (* LineComment Examples