Add tests for finding references from active pattern declarations

- Added test for full active pattern from declaration
- Added test for partial active pattern from definition
- Updated comment to clarify filtering behavior
- All 18 tests now pass (9 for BackgroundCompiler + 9 for TransparentCompiler)

Co-authored-by: TheAngryByrd <[email protected]>

Author: Copilot

src/FsAutoComplete.Core/Commands.fs

@@ -788,6 +788,8 @@ module Commands =
 
           // For Active Pattern Cases, FCS returns all cases in the pattern, not just the specific one
           // We need to filter to only the symbol that matches our query
+          // BUT: if querying from the Active Pattern declaration itself (FSharpMemberOrFunctionOrValue),
+          // we want ALL cases, not filtered
           match symbolUse.Symbol with
           | :? FSharpActivePatternCase as apc ->
             baseFiltered

test/FsAutoComplete.Tests.Lsp/FindReferencesTests.fs

@@ -665,7 +665,27 @@ let private activePatternTests state =
     }
 
   serverTestList "active patterns" state defaultConfigDto None (fun server ->
-    [ testCaseAsync "can find references for Active Pattern Case 'Even' without including 'Odd'"
+    [ testCaseAsync "can find references for full Active Pattern from declaration"
+      <| checkRanges
+        server
+        """
+        module MyModule =
+          let ($D<|Even|$0Odd|>D$) value =
+            if value % 2 = 0 then Even else Odd
+
+        open MyModule
+        let _ = ($<|Even|Odd|>$) 42
+        let _ = MyModule.($<|Even|Odd|>$) 42
+        let _ =
+          match 42 with
+          | Even -> ()
+          | Odd -> ()
+        let _ =
+          match 42 with
+          | MyModule.Even -> ()
+          | MyModule.Odd -> ()
+        """
+      testCaseAsync "can find references for Active Pattern Case 'Even' without including 'Odd'"
       <| checkRanges
         server
         """
@@ -720,6 +740,25 @@ let private activePatternTests state =
           | MyModule.$<ParseInt>$ i -> i
           | _ -> 0
         """
+      testCaseAsync "can find references for Partial Active Pattern - from definition"
+      <| checkRanges
+        server
+        """
+        module MyModule =
+          let ($D<|ParseInt|$0_|>D$) (str: string) =
+            let success, i = System.Int32.TryParse str
+            if success then Some i else None
+
+        open MyModule
+        let _ =
+          match "42" with
+          | ParseInt i -> i
+          | _ -> 0
+        let _ =
+          match "test" with
+          | MyModule.ParseInt i -> i
+          | _ -> 0
+        """
       testCaseAsync "can find references for three-case Active Pattern - first case"
       <| checkRanges
         server