Add flag for enabling transparent compiler support

Author: TheAngryByrd

release/package.json

@@ -545,6 +545,11 @@
           "description": "When selecting an external symbols in autocomplete, insert the full name to the editor rather than open its module/namespace. Also allow filtering suggestions by typing its full name. \n\n Requires \u0060FSharp.externalAutocomplete\u0060 enabled.",
           "type": "boolean"
         },
+        "FSharp.fcs.transparentCompiler.enabled": {
+          "default": false,
+          "description": "EXPERIMENTAL: Enables the FSharp Cpmpiler Service's [transparent compiler](https://github.com/dotnet/fsharp/pull/15179) feature. Requires restart.",
+          "type": "boolean"
+        },
         "FSharp.fsac.attachDebugger": {
           "default": false,
           "description": "Appends the \u0027--attachdebugger\u0027 argument to fsac, this will allow you to attach a debugger.",
@@ -1791,4 +1796,4 @@
     "url": "https://github.com/ionide/ionide-vscode-fsharp.git"
   },
   "version": "7.18.2"
-}
+}

src/Core/LanguageService.fs

@@ -675,6 +675,9 @@ Consider:
             let enableProjectGraph =
                 "FSharp.enableMSBuildProjectGraph" |> Configuration.get false
 
+            let useTransparentCompiler =
+                "FSharp.fcs.transparentCompiler.enabled" |> Configuration.get false
+
             let tryBool x =
                 // Boolean.TryParse generates: TypeError: e.match is not a function if we don't call toString first
                 match Boolean.TryParse(x.ToString()) with
@@ -915,6 +918,8 @@ Consider:
                           if fsacSilencedLogs <> null && fsacSilencedLogs.Length > 0 then
                               yield "--filter"
                               yield! fsacSilencedLogs
+                          if useTransparentCompiler then
+                              yield "--use-fcs-transparent-compiler"
                           match c.storageUri with
                           | Some uri ->
                               let storageDir = uri.fsPath