Do not export Flow_js.lookup_builtin functions

Summary:
The calls to `lookup_builtin_*` functions of merge_service.ml and new_check_service.ml
can be handled without creating any new constraints, ie from flow_js_utils.ml, instead
of flow_js.ml.

Reviewed By: samwgoldman

Differential Revision: D28659924

fbshipit-source-id: 507442171533cf0ec35316b55e8aaca0e8a56c09

src/services/inference/merge_service.ml

@@ -104,7 +104,7 @@ let merge_context ~options ~reader master_cx component =
     let builtin_name = Reason.internal_module_name (Modulename.to_string mname) in
     fun loc ->
       let reason = Reason.mk_reason desc loc in
-      Flow_js.lookup_builtin_strict cx builtin_name reason
+      Flow_js_utils.lookup_builtin_strict cx builtin_name reason
   in
   let mk_resource_module_t cx filename loc = Import_export.mk_resource_module_t cx loc filename in
   let mk_cyclic_module_t component_rec i _loc =
@@ -123,7 +123,7 @@ let merge_context ~options ~reader master_cx component =
     fun loc ->
       let reason = Reason.(mk_reason desc loc) in
       let default = Type.(AnyT (reason, Untyped)) in
-      Flow_js.lookup_builtin_with_default cx builtin_name default
+      Flow_js_utils.lookup_builtin_with_default cx builtin_name default
   in
   let file_dependency component_rec cx file_key mref =
     let open Module_heaps in

src/services/inference/new_check_service.ml

@@ -171,7 +171,7 @@ let unknown_module_t cx mref provider =
     if react_server_module_err then
       Flow_js.add_output cx (Error_message.EImportInternalReactServerModule loc);
     let reason = Reason.mk_reason desc loc in
-    Flow_js.lookup_builtin_strict cx m_name reason
+    Flow_js_utils.lookup_builtin_strict cx m_name reason
 
 let resource_module_t cx f loc = Import_export.mk_resource_module_t cx loc f
 
@@ -181,7 +181,7 @@ let unchecked_module_t cx mref =
   fun loc ->
     let reason = Reason.mk_reason desc loc in
     let default = Type.(AnyT (reason, Untyped)) in
-    Flow_js.lookup_builtin_with_default cx m_name default
+    Flow_js_utils.lookup_builtin_with_default cx m_name default
 
 let get_lint_severities metadata options =
   let lint_severities = Options.lint_severities options in

src/typing/flow_js.ml

@@ -9765,8 +9765,7 @@ struct
    * Does not add an entry that requires a
    * write later. *)
   and lookup_builtin_with_default cx x default =
-    let builtins = Context.builtins cx in
-    let builtin = Builtins.get_builtin builtins x ~on_missing:(fun () -> default) in
+    let builtin = Flow_js_utils.lookup_builtin_with_default cx x default in
     Tvar.mk_where cx (reason_of_t default) (fun t -> flow_t cx (builtin, t))
 
   and get_builtin_typeapp cx ?trace reason x targs =

src/typing/flow_js.mli

@@ -108,10 +108,6 @@ val add_output : Context.t -> ?trace:Type.trace -> Error_message.t -> unit
 
 val get_builtin : Context.t -> ?trace:Type.trace -> name -> reason -> Type.t
 
-val lookup_builtin_strict : Context.t -> name -> reason -> Type.t
-
-val lookup_builtin_with_default : Context.t -> name -> Type.t -> Type.t
-
 val get_builtin_type : Context.t -> ?trace:Type.trace -> reason -> ?use_desc:bool -> name -> Type.t
 
 val set_builtin : Context.t -> ?trace:Type.trace -> name -> Type.t -> unit

src/typing/flow_js_utils.ml

@@ -682,6 +682,10 @@ let lookup_builtin_strict cx x reason =
       add_output cx (Error_message.EBuiltinLookupFailed { reason; name = Some x });
       AnyT.error_of_kind UnresolvedName reason)
 
+let lookup_builtin_with_default cx x default =
+  let builtins = Context.builtins cx in
+  Builtins.get_builtin builtins x ~on_missing:(fun () -> default)
+
 let lookup_builtin_typeapp cx reason x targs =
   let t = lookup_builtin_strict cx x reason in
   typeapp reason t targs

src/typing/merge_js.ml

@@ -136,7 +136,7 @@ let explicit_unchecked_require cx (m, loc) =
   let reason = Reason.(mk_reason (RUntypedModule m) loc) in
   let m_name = Reason.internal_module_name m in
   let default_t = Type.AnyT (reason, Type.Untyped) in
-  let from_t = Flow_js.lookup_builtin_with_default cx m_name default_t in
+  let from_t = Flow_js_utils.lookup_builtin_with_default cx m_name default_t in
 
   (* flow the declared module type to importing context *)
   let to_t = Context.find_require cx loc in