Making code fixes generate multiple suggestions again

vsintegration/src/FSharp.Editor/CodeFixes/CodeFixHelpers.fs

@@ -82,8 +82,7 @@ module internal CodeFixHelpers =
                     reportCodeFixTelemetry context.Diagnostics context.Document codeFix.Name [||]
                     return doc
                 }
-                |> CancellableTask.start cancellationToken),
-            codeFix.Name
+                |> CancellableTask.start cancellationToken)
         )
 
 [<AutoOpen>]
@@ -100,6 +99,16 @@ module internal CodeFixExtensions =
             }
             |> CancellableTask.startAsTask ctx.CancellationToken
 
+        member ctx.RegisterFsharpFixes(codeFix: IFSharpMultiCodeFixProvider) =
+            cancellableTask {
+                let! codeFixes = codeFix.GetCodeFixesAsync ctx
+
+                for codeFix in codeFixes do
+                    let codeAction = CodeFixHelpers.createTextChangeCodeFix (codeFix, ctx)
+                    ctx.RegisterCodeFix(codeAction, ctx.Diagnostics)
+            }
+            |> CancellableTask.startAsTask ctx.CancellationToken
+
         member ctx.GetSourceTextAsync() =
             cancellableTask {
                 let! cancellationToken = CancellableTask.getCancellationToken ()

vsintegration/src/FSharp.Editor/CodeFixes/IFSharpCodeFix.fs

@@ -14,5 +14,10 @@ type FSharpCodeFix =
         Changes: TextChange list
     }
 
+/// Provider can generate at most 1 suggestion.
 type IFSharpCodeFixProvider =
     abstract member GetCodeFixIfAppliesAsync: context: CodeFixContext -> CancellableTask<FSharpCodeFix voption>
+
+/// Provider can generate multiple suggestions.
+type IFSharpMultiCodeFixProvider =
+    abstract member GetCodeFixesAsync: context: CodeFixContext -> CancellableTask<FSharpCodeFix seq>

vsintegration/src/FSharp.Editor/CodeFixes/ReplaceWithSuggestion.fs

@@ -23,12 +23,12 @@ type internal ReplaceWithSuggestionCodeFixProvider [<ImportingConstructor>] () =
 
     override this.RegisterCodeFixesAsync context =
         if context.Document.Project.IsFSharpCodeFixesSuggestNamesForErrorsEnabled then
-            context.RegisterFsharpFix this
+            context.RegisterFsharpFixes this
         else
             Task.CompletedTask
 
-    interface IFSharpCodeFixProvider with
-        member _.GetCodeFixIfAppliesAsync context =
+    interface IFSharpMultiCodeFixProvider with
+        member _.GetCodeFixesAsync context =
             cancellableTask {
                 let! parseFileResults, checkFileResults =
                     context.Document.GetFSharpParseAndCheckResultsAsync(nameof ReplaceWithSuggestionCodeFixProvider)
@@ -49,20 +49,14 @@ type internal ReplaceWithSuggestionCodeFixProvider [<ImportingConstructor>] () =
                     for item in declInfo.Items do
                         addToBuffer item.NameInList
 
-                let suggestionOpt =
+                return
                     CompilerDiagnostics.GetSuggestedNames addNames unresolvedIdentifierText
-                    |> Seq.tryHead
-
-                match suggestionOpt with
-                | None -> return ValueNone
-                | Some suggestion ->
-                    let replacement = PrettyNaming.NormalizeIdentifierBackticks suggestion
-
-                    return
-                        ValueSome
-                            {
-                                Name = CodeFix.ReplaceWithSuggestion
-                                Message = CompilerDiagnostics.GetErrorMessage(FSharpDiagnosticKind.ReplaceWithSuggestion suggestion)
-                                Changes = [ TextChange(context.Span, replacement) ]
-                            }
+                    |> Seq.map (fun suggestion ->
+                        let replacement = PrettyNaming.NormalizeIdentifierBackticks suggestion
+
+                        {
+                            Name = CodeFix.ReplaceWithSuggestion
+                            Message = CompilerDiagnostics.GetErrorMessage(FSharpDiagnosticKind.ReplaceWithSuggestion suggestion)
+                            Changes = [ TextChange(context.Span, replacement) ]
+                        })
             }

vsintegration/tests/FSharp.Editor.Tests/CodeFixes/CodeFixTestFramework.fs

@@ -56,11 +56,13 @@ let getRelevantDiagnostics (document: Document) =
     |> CancellableTask.startWithoutCancellation
     |> fun task -> task.Result
 
-let createTestCodeFixContext (code: string) document (mode: Mode) diagnosticIds =
+let createTestCodeFixContext (code: string) (mode: Mode) (fixProvider: 'T :> CodeFixProvider) =
     cancellableTask {
         let! cancellationToken = CancellableTask.getCancellationToken ()
 
         let sourceText = SourceText.From code
+        let document = getDocument code mode
+        let diagnosticIds = fixProvider.FixableDiagnosticIds
 
         let diagnostics =
             match mode with
@@ -92,12 +94,11 @@ let createTestCodeFixContext (code: string) document (mode: Mode) diagnosticIds
         return CodeFixContext(document, textSpan, roslynDiagnostics, mockAction, cancellationToken)
     }
 
-let tryFix (code: string) mode (fixProvider: 'T when 'T :> IFSharpCodeFixProvider and 'T :> CodeFixProvider) =
+let tryFix (code: string) mode (fixProvider: 'T :> IFSharpCodeFixProvider) =
     cancellableTask {
         let sourceText = SourceText.From code
-        let document = getDocument code mode
 
-        let! context = createTestCodeFixContext code document mode fixProvider.FixableDiagnosticIds
+        let! context = createTestCodeFixContext code mode fixProvider
 
         let! result = fixProvider.GetCodeFixIfAppliesAsync context
 
@@ -112,3 +113,22 @@ let tryFix (code: string) mode (fixProvider: 'T when 'T :> IFSharpCodeFixProvide
     }
     |> CancellableTask.startWithoutCancellation
     |> fun task -> task.Result
+
+let multiFix (code: string) mode (fixProvider: 'T :> IFSharpMultiCodeFixProvider) =
+    cancellableTask {
+        let sourceText = SourceText.From code
+
+        let! context = createTestCodeFixContext code mode fixProvider
+
+        let! result = fixProvider.GetCodeFixesAsync context
+
+        return
+            result
+            |> Seq.map (fun codeFix ->
+                {
+                    Message = codeFix.Message
+                    FixedCode = (sourceText.WithChanges codeFix.Changes).ToString()
+                })
+    }
+    |> CancellableTask.startWithoutCancellation
+    |> fun task -> task.Result

vsintegration/tests/FSharp.Editor.Tests/CodeFixes/ReplaceWithSuggestionTests.fs

@@ -19,7 +19,7 @@ let song = { Titel = "Jigsaw Falling Into Place" }
 """
 
     let expected =
-        Some
+        [
             {
                 Message = "Replace with 'Title'"
                 FixedCode =
@@ -29,8 +29,9 @@ type Song = { Title : string }
 let song = { Title = "Jigsaw Falling Into Place" }
 """
             }
+        ]
 
-    let actual = codeFix |> tryFix code Auto
+    let actual = codeFix |> multiFix code Auto
 
     Assert.Equal(expected, actual)
 
@@ -44,7 +45,7 @@ let someSong : Wrong = { Title = "The Narcissist" }
 """
 
     let expected =
-        Some
+        [
             {
                 Message = "Replace with 'Song'"
                 FixedCode =
@@ -54,8 +55,47 @@ type Song = { Title : string }
 let someSong : Song = { Title = "The Narcissist" }
 """
             }
+        ]
 
-    let actual = codeFix |> tryFix code Auto
+    let actual = codeFix |> multiFix code Auto
+
+    Assert.Equal(expected, actual)
+
+[<Fact>]
+let ``Fixes FS0039 - multiple suggestions`` () =
+    let code =
+        """
+type TheType1() = class end
+type TheType3() = class end
+
+let test = TheType2()
+"""
+
+    let expected =
+        [
+            {
+                Message = "Replace with 'TheType1'"
+                FixedCode =
+                    """
+type TheType1() = class end
+type TheType3() = class end
+
+let test = TheType1()
+"""
+            }
+            {
+                Message = "Replace with 'TheType3'"
+                FixedCode =
+                    """
+type TheType1() = class end
+type TheType3() = class end
+
+let test = TheType3()
+"""
+            }
+        ]
+
+    let actual = codeFix |> multiFix code Auto
 
     Assert.Equal(expected, actual)
 
@@ -70,9 +110,9 @@ module Module2 =
     let song = { Titel = "Jigsaw Falling Into Place" }
 """
 
-    let expected = None
+    let expected = []
 
-    let actual = codeFix |> tryFix code Auto
+    let actual = codeFix |> multiFix code Auto
 
     Assert.Equal(expected, actual)
 
@@ -83,9 +123,9 @@ let ``Doesn't fix FS0039 for random undefined stuff`` () =
 let f = g
 """
 
-    let expected = None
+    let expected = []
 
-    let actual = codeFix |> tryFix code Auto
+    let actual = codeFix |> multiFix code Auto
 
     Assert.Equal(expected, actual)
 
@@ -100,7 +140,7 @@ let song = Song(titel = "Under The Milky Way")
 """
 
     let expected =
-        Some
+        [
             {
                 Message = "Replace with 'title'"
                 FixedCode =
@@ -111,7 +151,8 @@ type Song(title: string) =
 let song = Song(title = "Under The Milky Way")
 """
             }
+        ]
 
-    let actual = codeFix |> tryFix code Auto
+    let actual = codeFix |> multiFix code Auto
 
     Assert.Equal(expected, actual)