Always emit conditional attributes in FCS

src/fsharp/TypeChecker.fs

@@ -10829,8 +10829,10 @@ and TcAttribute canFail cenv (env: TcEnv) attrTgt (synAttr: SynAttribute)  =
     let conditionalCallDefineOpt = TryFindTyconRefStringAttribute cenv.g mAttr cenv.g.attrib_ConditionalAttribute tcref 
 
     match conditionalCallDefineOpt with 
+#if !COMPILER_SERVICE_AS_DLL 
     | Some d when not (List.contains d cenv.conditionalDefines) -> 
         [], false
+#endif
     | _ ->
 
          // REVIEW: take notice of inherited? 

tests/service/Symbols.fs

@@ -100,4 +100,27 @@ module Mod2 =
          mod1val1.XmlDocSig |> shouldEqual "P:Mod1.val1"
          mod2func2.XmlDocSig |> shouldEqual "M:Mod1.Mod2.func2"
 
-
+
+module Attributes =
+    [<Test>]
+    let ``Emit conditional attributes`` () =
+        let source = """
+open System
+open System.Diagnostics
+
+[<Conditional("Bar")>]
+type FooAttribute() =
+    inherit Attribute()
+
+[<Foo>]
+let x = 123
+"""
+        let fileName, options = mkTestFileAndOptions source [| |]
+        let _, checkResults = parseAndCheckFile fileName source options    
+
+        checkResults.GetAllUsesOfAllSymbolsInFile()
+         |> Async.RunSynchronously
+         |> Array.tryFind (fun su -> su.Symbol.DisplayName = "x")
+         |> Option.orElseWith (fun _ -> failwith "Could not get symbol")
+         |> Option.map (fun su -> su.Symbol :?> FSharpMemberOrFunctionOrValue)
+         |> Option.iter (fun symbol -> symbol.Attributes.Count |> shouldEqual 1)