Add ChangeRefCellDerefToNotExpression code fixer

src/fsharp/service/ServiceUntypedParse.fs

@@ -100,6 +100,24 @@ type FSharpParseFileResults(errors: FSharpErrorInfo[], input: ParsedInput option
 
     member scope.ParseTree = input
 
+    member scope.TryRangeOfRefCellDereferenceContainingPos expressionPos =
+        match input with
+        | Some input ->
+            let res = 
+                AstTraversal.Traverse(expressionPos, input, { new AstTraversal.AstVisitorBase<_>() with 
+                    member _.VisitExpr(_, _, defaultTraverse, expr) =
+                        match expr with
+                        | SynExpr.App(_, false, SynExpr.Ident funcIdent, expr, _) ->
+                            if funcIdent.idText = "op_Dereference" && rangeContainsPos expr.Range expressionPos then
+                                Some funcIdent.idRange
+                            else
+                                None
+                        | _ -> defaultTraverse expr
+                })
+            res
+        | None ->
+            None
+
     member scope.FindNoteworthyParamInfoLocations pos = 
         match input with
         | Some input -> FSharpNoteworthyParamInfoLocations.Find(pos, input)

src/fsharp/service/ServiceUntypedParse.fsi

@@ -19,6 +19,13 @@ type public FSharpParseFileResults =
     /// The syntax tree resulting from the parse
     member ParseTree : ParsedInput option
 
+    /// <summary>
+    /// Given the position of an expression, attempts to find the range of the
+    /// '!' in a derefence operation of that expression, like:
+    /// '!expr', '!(expr)', etc.
+    /// </summary>
+    member TryRangeOfRefCellDereferenceContainingPos: expressionPos: pos -> Option<range>
+
     /// Notable parse info for ParameterInfo at a given location
     member FindNoteworthyParamInfoLocations : pos:pos -> FSharpNoteworthyParamInfoLocations option
 

tests/FSharp.Compiler.Service.Tests/SurfaceArea.netstandard.fs

@@ -22749,6 +22749,7 @@ FSharp.Compiler.SourceCodeServices.FSharpParseFileResults: Boolean get_ParseHadE
 FSharp.Compiler.SourceCodeServices.FSharpParseFileResults: FSharp.Compiler.SourceCodeServices.FSharpErrorInfo[] Errors
 FSharp.Compiler.SourceCodeServices.FSharpParseFileResults: FSharp.Compiler.SourceCodeServices.FSharpErrorInfo[] get_Errors()
 FSharp.Compiler.SourceCodeServices.FSharpParseFileResults: FSharp.Compiler.SourceCodeServices.FSharpNavigationItems GetNavigationItems()
+FSharp.Compiler.SourceCodeServices.FSharpParseFileResults: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Range+range] TryRangeOfRefCellDereferenceContainingPos(pos)
 FSharp.Compiler.SourceCodeServices.FSharpParseFileResults: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Range+range] ValidateBreakpointLocation(pos)
 FSharp.Compiler.SourceCodeServices.FSharpParseFileResults: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.SourceCodeServices.FSharpNoteworthyParamInfoLocations] FindNoteworthyParamInfoLocations(pos)
 FSharp.Compiler.SourceCodeServices.FSharpParseFileResults: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.SyntaxTree+ParsedInput] ParseTree

tests/service/ServiceUntypedParseTests.fs

@@ -305,3 +305,56 @@ type T =
     new (x:int) = ()
 """
         getTypeMemberRange source |> shouldEqual [ (3, 4), (3, 20) ]
+
+
+[<Test>]
+let ``TryRangeOfRefCellDereferenceContainingPos - simple``() =
+    let source = """
+let x = false
+let y = !x
+"""
+    let parseFileResults, _ = getParseAndCheckResults source
+    let res = parseFileResults.TryRangeOfRefCellDereferenceContainingPos (mkPos 3 9)
+    match res with
+    | Some res ->
+        res
+        |> tups
+        |> fst
+        |> shouldEqual (3, 8)
+    | None ->
+        Assert.Fail("No deref operator found in source.")
+
+[<Test>]
+let ``TryRangeOfRefCellDereferenceContainingPos - parens``() =
+    let source = """
+let x = false
+let y = !(x)
+"""
+    let parseFileResults, _ = getParseAndCheckResults source
+    let res = parseFileResults.TryRangeOfRefCellDereferenceContainingPos (mkPos 3 10)
+    match res with
+    | Some res ->
+        res
+        |> tups
+        |> fst
+        |> shouldEqual (3, 8)
+    | None ->
+        Assert.Fail("No deref operator found in source.")
+
+
+[<Test>]
+let ``TryRangeOfRefCellDereferenceContainingPos - binary expr``() =
+    let source = """
+let x = false
+let y = !(x = false)
+"""
+    let parseFileResults, _ = getParseAndCheckResults source
+    let res = parseFileResults.TryRangeOfRefCellDereferenceContainingPos (mkPos 3 10)
+    match res with
+    | Some res ->
+        res
+        |> tups
+        |> fst
+        |> shouldEqual (3, 8)
+    | None ->
+        Assert.Fail("No deref operator found in source.")

vsintegration/src/FSharp.Editor/CodeFix/ChangeRefCellDerefToNotExpression.fs

@@ -0,0 +1,52 @@
+// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
+
+namespace Microsoft.VisualStudio.FSharp.Editor
+
+open System.Composition
+open System.Threading.Tasks
+
+open Microsoft.CodeAnalysis.Text
+open Microsoft.CodeAnalysis.CodeFixes
+
+[<ExportCodeFixProvider(FSharpConstants.FSharpLanguageName, Name = "ChangeRefCellDerefToNotExpression"); Shared>]
+type internal FSharpChangeRefCellDerefToNotExpressionCodeFixProvider
+    [<ImportingConstructor>]
+    (
+        checkerProvider: FSharpCheckerProvider, 
+        projectInfoManager: FSharpProjectOptionsManager
+    ) =
+    inherit CodeFixProvider()
+
+    static let userOpName = "FSharpChangeRefCellDerefToNotExpressionCodeFix"
+    let fixableDiagnosticIds = set ["FS0001"]
+
+    override __.FixableDiagnosticIds = Seq.toImmutableArray fixableDiagnosticIds
+
+    override this.RegisterCodeFixesAsync context : Task =
+        asyncMaybe {
+            let document = context.Document
+            let! parsingOptions, _ = projectInfoManager.TryGetOptionsForEditingDocumentOrProject(document, context.CancellationToken, userOpName)
+            let! sourceText = context.Document.GetTextAsync(context.CancellationToken)
+            let! parseResults = checkerProvider.Checker.ParseFile(document.FilePath, sourceText.ToFSharpSourceText(), parsingOptions, userOpName) |> liftAsync
+
+            let errorRange = RoslynHelpers.TextSpanToFSharpRange(document.FilePath, context.Span, sourceText)
+            let! derefRange = parseResults.TryRangeOfRefCellDereferenceContainingPos errorRange.Start
+            let! derefSpan = RoslynHelpers.TryFSharpRangeToTextSpan(sourceText, derefRange)
+
+            let title = SR.UseNotForNegation()
+
+            let diagnostics =
+                context.Diagnostics
+                |> Seq.filter (fun x -> fixableDiagnosticIds |> Set.contains x.Id)
+                |> Seq.toImmutableArray
+
+            let codeFix =
+                CodeFixHelpers.createTextChangeCodeFix(
+                    title,
+                    context,
+                    (fun () -> asyncMaybe.Return [| TextChange(derefSpan, "not ") |]))
+
+            context.RegisterCodeFix(codeFix, diagnostics)
+        }
+        |> Async.Ignore
+        |> RoslynHelpers.StartAsyncUnitAsTask(context.CancellationToken) 

vsintegration/src/FSharp.Editor/FSharp.Editor.fsproj

@@ -89,6 +89,7 @@
     <Compile Include="Commands\FsiCommandService.fs" />
     <Compile Include="Commands\XmlDocCommandService.fs" />
     <Compile Include="CodeFix\CodeFixHelpers.fs" />
+    <Compile Include="CodeFix\ChangeRefCellDerefToNotExpression.fs" />
     <Compile Include="CodeFix\WrapExpressionInParentheses.fs" />
     <Compile Include="CodeFix\ChangePrefixNegationToInfixSubtraction.fs" />
     <Compile Include="CodeFix\AddNewKeywordToDisposableConstructorInvocation.fs" />

vsintegration/src/FSharp.Editor/FSharp.Editor.resx

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <root>
   <!-- 
     Microsoft ResX Schema 
@@ -219,6 +219,9 @@
   <data name="FSharpDisposableTopLevelValuesClassificationType" xml:space="preserve">
     <value>F# Dispostable Values (top-level)</value>
   </data>
+  <data name="UseNotForNegation" xml:space="preserve">
+    <value>Use 'not' to negate expression</value>
+  </data>
   <data name="WrapExpressionInParentheses" xml:space="preserve">
     <value>Wrap expression in parentheses</value>
   </data>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.cs.xlf

@@ -177,6 +177,11 @@
         <target state="translated">Formátování</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.de.xlf

@@ -177,6 +177,11 @@
         <target state="translated">Formatierung</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.es.xlf

@@ -177,6 +177,11 @@
         <target state="translated">Formato</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.fr.xlf

@@ -177,6 +177,11 @@
         <target state="translated">Mise en forme</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.it.xlf

@@ -177,6 +177,11 @@
         <target state="translated">Formattazione</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.ja.xlf

@@ -177,6 +177,11 @@
         <target state="translated">書式設定</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.ko.xlf

@@ -177,6 +177,11 @@
         <target state="translated">서식</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.pl.xlf

@@ -177,6 +177,11 @@
         <target state="translated">Formatowanie</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.pt-BR.xlf

@@ -177,6 +177,11 @@
         <target state="translated">Formatação</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.ru.xlf

@@ -177,6 +177,11 @@
         <target state="translated">Форматирование</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.tr.xlf

@@ -177,6 +177,11 @@
         <target state="translated">Biçimlendirme</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.zh-Hans.xlf

@@ -177,6 +177,11 @@
         <target state="translated">正在格式化</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>

vsintegration/src/FSharp.Editor/xlf/FSharp.Editor.zh-Hant.xlf

@@ -177,6 +177,11 @@
         <target state="translated">格式化</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNotForNegation">
+        <source>Use 'not' to negate expression</source>
+        <target state="new">Use 'not' to negate expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="WrapExpressionInParentheses">
         <source>Wrap expression in parentheses</source>
         <target state="new">Wrap expression in parentheses</target>