Fix finding references to active pattern cases (#14966)

* active pattern find references - only search for the one provided, not all . And works also for .fsi files.

src/Compiler/Service/ItemKey.fs

@@ -15,6 +15,7 @@ open FSharp.Compiler.Text
 open FSharp.Compiler.Text.Range
 open FSharp.Compiler.TypedTree
 open FSharp.Compiler.TypedTreeBasics
+open FSharp.Compiler.Syntax.PrettyNaming
 
 #nowarn "9"
 #nowarn "51"
@@ -301,6 +302,19 @@ and [<Sealed>] ItemKeyStoreBuilder() =
             | ParentNone -> writeChar '%'
             | Parent eref -> writeEntityRef eref
 
+    let writeActivePatternCase (apInfo: ActivePatternInfo) index =
+        writeString ItemKeyTags.itemActivePattern
+
+        match apInfo.ActiveTagsWithRanges with
+        | (_, m) :: _ -> m.FileName |> Path.GetFileNameWithoutExtension |> writeString
+        | _ -> ()
+
+        for tag in apInfo.ActiveTags do
+            writeChar '|'
+            writeString tag
+
+        writeInt32 index
+
     member _.Write(m: range, item: Item) =
         writeRange m
 
@@ -325,13 +339,9 @@ and [<Sealed>] ItemKeyStoreBuilder() =
             writeEntityRef info.TyconRef
             writeString info.LogicalName
 
-        | Item.ActivePatternResult (info, _, _, _) ->
-            writeString ItemKeyTags.itemActivePattern
-            info.ActiveTags |> List.iter writeString
+        | Item.ActivePatternResult (info, _, index, _) -> writeActivePatternCase info index
 
-        | Item.ActivePatternCase elemRef ->
-            writeString ItemKeyTags.itemActivePattern
-            elemRef.ActivePatternInfo.ActiveTags |> List.iter writeString
+        | Item.ActivePatternCase elemRef -> writeActivePatternCase elemRef.ActivePatternInfo elemRef.CaseIndex
 
         | Item.ExnCase tcref ->
             writeString ItemKeyTags.itemExnCase

tests/FSharp.Compiler.ComponentTests/FSharpChecker/FindReferences.fs

@@ -301,3 +301,120 @@ let x = MyType()
             "FileProgram.fs", 6, 8, 14
         ])
     }
+
+
+module ActivePatterns =
+
+    /// https://github.com/dotnet/fsharp/issues/14206
+    [<Fact>]
+    let ``Finding references to an active pattern case shouldn't find other cases`` () =
+        let source = """
+let (|Even|Odd|) v =
+    if v % 2 = 0 then Even else Odd
+match 2 with
+| Even -> ()
+| Odd -> ()
+"""
+        let fileName, options, checker = singleFileChecker source
+
+        let symbolUse = getSymbolUse fileName source "Even" options checker |> Async.RunSynchronously
+
+        checker.FindBackgroundReferencesInFile(fileName, options, symbolUse.Symbol, fastCheck = true)
+        |> Async.RunSynchronously
+        |> expectToFind [
+            fileName, 2, 6, 10
+            fileName, 3, 22, 26
+            fileName, 5, 2, 6
+        ]
+
+    [<Fact>]
+    let ``We don't find references to cases from other active patterns with the same name`` () =
+
+        let source = """
+module One =
+
+    let (|Even|Odd|) v =
+        if v % 2 = 0 then Even else Odd
+    match 2 with
+    | Even -> ()
+    | Odd -> ()
+
+module Two =
+
+    let (|Even|Steven|) v =
+        if v % 3 = 0 then Steven else Even
+    match 2 with
+    | Even -> ()
+    | Steven -> ()
+"""
+
+        let fileName, options, checker = singleFileChecker source
+
+        let symbolUse = getSymbolUse fileName source "Even" options checker |> Async.RunSynchronously
+
+        checker.FindBackgroundReferencesInFile(fileName, options, symbolUse.Symbol, fastCheck = true)
+        |> Async.RunSynchronously
+        |> expectToFind [
+            fileName, 4, 10, 14
+            fileName, 5, 26, 30
+            fileName, 7, 6, 10
+        ]
+
+    [<Fact>]
+    let ``We don't find references to cases the same active pattern defined in a different file`` () =
+
+        let source = """
+let (|Even|Odd|) v =
+    if v % 2 = 0 then Even else Odd
+match 2 with
+| Even -> ()
+| Odd -> ()
+"""
+        SyntheticProject.Create(
+            { sourceFile "First" [] with Source = source },
+            { sourceFile "Second" [] with Source = source }
+        ).Workflow {
+            placeCursor "First" "Even"
+            findAllReferences (expectToFind [
+                "FileFirst.fs", 3, 6, 10
+                "FileFirst.fs", 4, 22, 26
+                "FileFirst.fs", 6, 2, 6
+            ])
+        }
+
+    [<Fact>]
+    let ``We find active patterns in other files when there are signature files`` () =
+
+        SyntheticProject.Create(
+            { sourceFile "First" [] with
+                Source = "let (|Even|Odd|) v = if v % 2 = 0 then Even else Odd"
+                SignatureFile = AutoGenerated },
+            { sourceFile "Second" [] with
+                Source = """
+open ModuleFirst
+match 2 with | Even -> () | Odd -> ()
+""" }
+        ).Workflow {
+            placeCursor "Second" "Even"
+            findAllReferences (expectToFind [
+                "FileFirst.fs", 2, 6, 10
+                "FileFirst.fs", 2, 39, 43
+                "FileSecond.fs", 4, 15, 19
+            ])
+        }
+
+    /// Bug: https://github.com/dotnet/fsharp/issues/14969
+    [<Fact>]
+    let ``We DON'T find active patterns in signature files`` () =
+        SyntheticProject.Create(
+            { sourceFile "First" [] with
+                Source = "let (|Even|Odd|) v = if v % 2 = 0 then Even else Odd"
+                SignatureFile = AutoGenerated }
+        ).Workflow {
+            placeCursor "First" "Even"
+            findAllReferences (expectToFind [
+                "FileFirst.fs", 2, 6, 10
+                "FileFirst.fs", 2, 39, 43
+                //"FileFirst.fsi", 4, 6, 10 <-- this should also be found
+            ])
+        }
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