diff --git a/analysis/src/CompletionBackEnd.ml b/analysis/src/CompletionBackEnd.ml
index b3e257b7f..670792189 100644
--- a/analysis/src/CompletionBackEnd.ml
+++ b/analysis/src/CompletionBackEnd.ml
@@ -1283,10 +1283,16 @@ let rec getCompletionsForContextPath ~package ~opens ~rawOpens ~allFiles ~pos
       |> completionsGetTypeEnv
     with
     | Some (typ, _envNotUsed) -> (
-      let arrayModulePath = ["Js"; "Array2"] in
-      let listModulePath = ["Belt"; "List"] in
-      let optionModulePath = ["Belt"; "Option"] in
-      let stringModulePath = ["Js"; "String2"] in
+      let {
+        arrayModulePath;
+        optionModulePath;
+        stringModulePath;
+        intModulePath;
+        floatModulePath;
+        promiseModulePath;
+      } =
+        package.builtInCompletionModules
+      in
       let getModulePath path =
         let rec loop (path : Path.t) =
           match path with
@@ -1296,9 +1302,15 @@ let rec getCompletionsForContextPath ~package ~opens ~rawOpens ~allFiles ~pos
         in
         match path with
         | Path.Pident id when Ident.name id = "array" -> arrayModulePath
-        | Path.Pident id when Ident.name id = "list" -> listModulePath
         | Path.Pident id when Ident.name id = "option" -> optionModulePath
         | Path.Pident id when Ident.name id = "string" -> stringModulePath
+        | Path.Pident id when Ident.name id = "int" -> intModulePath
+        | Path.Pident id when Ident.name id = "float" -> floatModulePath
+        | Path.Pident id when Ident.name id = "promise" -> promiseModulePath
+        | Path.Pident id when Ident.name id = "list" -> ["Belt"; "List"]
+        | Path.Pident id when Ident.name id = "lazy_t" -> ["Lazy"]
+        | Path.Pident id when Ident.name id = "result" -> ["Belt"; "Result"]
+        | Path.Pident id when Ident.name id = "char" -> ["Char"]
         | _ -> (
           match loop path with
           | _ :: rest -> List.rev rest
diff --git a/analysis/src/Packages.ml b/analysis/src/Packages.ml
index 81b7b0257..2a4bd73bd 100644
--- a/analysis/src/Packages.ml
+++ b/analysis/src/Packages.ml
@@ -93,6 +93,32 @@ let newBsPackage ~rootPath =
                pathsForModule;
                opens;
                namespace;
+               builtInCompletionModules =
+                 (if
+                  opens_from_bsc_flags
+                  |> List.find_opt (fun opn ->
+                         match opn with
+                         | ["ReScriptStdLib"] -> true
+                         | _ -> false)
+                  |> Option.is_some
+                 then
+                  {
+                    arrayModulePath = ["Array"];
+                    optionModulePath = ["Option"];
+                    stringModulePath = ["String"];
+                    intModulePath = ["Int"];
+                    floatModulePath = ["Float"];
+                    promiseModulePath = ["Promise"];
+                  }
+                 else
+                   {
+                     arrayModulePath = ["Js"; "Array2"];
+                     optionModulePath = ["Belt"; "Option"];
+                     stringModulePath = ["Js"; "String2"];
+                     intModulePath = ["Belt"; "Int"];
+                     floatModulePath = ["Belt"; "Float"];
+                     promiseModulePath = ["Js"; "Promise"];
+                   });
              })))
     | None -> None)
 
diff --git a/analysis/src/SharedTypes.ml b/analysis/src/SharedTypes.ml
index 1db9a8ca8..906669e78 100644
--- a/analysis/src/SharedTypes.ml
+++ b/analysis/src/SharedTypes.ml
@@ -361,12 +361,22 @@ type file = string
 
 module FileSet = Set.Make (String)
 
+type builtInCompletionModules = {
+  arrayModulePath: string list;
+  optionModulePath: string list;
+  stringModulePath: string list;
+  intModulePath: string list;
+  floatModulePath: string list;
+  promiseModulePath: string list;
+}
+
 type package = {
   rootPath: filePath;
   projectFiles: FileSet.t;
   dependenciesFiles: FileSet.t;
   pathsForModule: (file, paths) Hashtbl.t;
   namespace: string option;
+  builtInCompletionModules: builtInCompletionModules;
   opens: path list;
 }