[flow][refactor] Make CJSExtractNamedExportsTKit only depend on concr…

…etizer

Summary:
The goal of this stack is to gradually refactor the checking and merging of modules so that we can eventually kill `ModuleT`, which really doesn't belong in `Type.t`. Instead, we want to replace everywhere where we currently accept `Type.t` but only meant to accept either module or any with `(moduletype, any_info) result`.

This diff addresses the root of the evil: `CJSExtractNamedExportsTKit`. To create `module_type` from cjs, we have to concretize a potentially lazy type to grab information. Since everything in Flow_js and annotation_inference only outputs type, we are forced to make module information a type.

This diff changes it so that we only use flow_js and annotation_inference for concretization (see the added `ConcretizeForCJSExtractNamedExports` and `Annot_ConcretizeForCJSExtractNamedExports`). Everything else can be done completely within `CJSExtractNamedExportsTKit`.

With this refactor, it becomes clear in `type_sig_merge` and `module_info_analyzer` that when we are creating module types, we are dealing with only `ModuleT` the entire time, which enables future diffs in the stack to do further cleanup.

Changelog: [internal]

Reviewed By: panagosg7

Differential Revision: D68303855

fbshipit-source-id: b10749f9a4dc3b1b00f1d487453ccf8f9c496561

src/typing/annotation_inference.ml

@@ -16,13 +16,13 @@ let object_like_op = function
   | Annot_ThisSpecializeT _
   | Annot_UseT_TypeT _
   | Annot_ConcretizeForImportsExports _
+  | Annot_ConcretizeForCJSExtractNamedExports _
   | Annot_ConcretizeForInspection _
   | Annot_CJSRequireT _
   | Annot_ImportTypeofT _
   | Annot_ImportNamedT _
   | Annot_ImportDefaultT _
   | Annot_ImportModuleNsT _
-  | Annot_CJSExtractNamedExportsT _
   | Annot_ExportNamedT _
   | Annot_ExportTypeT _
   | Annot_AssertExportIsTypeT _
@@ -118,7 +118,8 @@ module type S = sig
     Type.t ->
     Type.t
 
-  val cjs_extract_named_exports : Context.t -> Reason.reason -> Type.moduletype -> Type.t -> Type.t
+  val lazy_cjs_extract_named_exports :
+    Context.t -> Reason.reason -> Type.moduletype -> Type.t -> Type.moduletype Lazy.t
 
   val import_default :
     Context.t -> Reason.t -> Type.import_kind -> string -> string -> bool -> Type.t -> Type.t
@@ -274,9 +275,6 @@ module rec ConsGen : S = struct
         cx
         export_t
         (Annot_ExportTypeT { reason; name_loc; preferred_def_locs; export_name; target_module_t })
-
-    let cjs_extract_named_exports cx (reason, local_module) t =
-      ConsGen.cjs_extract_named_exports cx reason local_module t
   end
 
   let with_concretized_type cx r f t = ConsGen.elab_t cx t (Annot_ConcretizeForImportsExports (r, f))
@@ -291,8 +289,7 @@ module rec ConsGen : S = struct
   module CopyNamedExportsTKit = Flow_js_utils.CopyNamedExportsT_kit (Import_export_helper)
   module CopyTypeExportsTKit = Flow_js_utils.CopyTypeExportsT_kit (Import_export_helper)
   module ExportTypeTKit = Flow_js_utils.ExportTypeT_kit (Import_export_helper)
-  module CJSExtractNamedExportsTKit =
-    Flow_js_utils.CJSExtractNamedExportsT_kit (Import_export_helper)
+  module CJSExtractNamedExportsTKit = Flow_js_utils.CJSExtractNamedExportsTKit
 
   (***********)
   (* GetProp *)
@@ -666,8 +663,7 @@ module rec ConsGen : S = struct
       CopyNamedExportsTKit.on_AnyT cx target_module
     | (AnyT (_, _), Annot_CopyTypeExportsT (_, target_module)) ->
       CopyTypeExportsTKit.on_AnyT cx target_module
-    | (_, Annot_CJSExtractNamedExportsT (reason, local_module)) ->
-      CJSExtractNamedExportsTKit.on_concrete_type cx (reason, local_module) t
+    | (l, Annot_ConcretizeForCJSExtractNamedExports _) -> l
     (******************)
     (* Module imports *)
     (******************)
@@ -1408,8 +1404,15 @@ module rec ConsGen : S = struct
   and export_named cx reason export_kind value_exports_tmap type_exports_tmap t =
     elab_t cx t (Annot_ExportNamedT { reason; value_exports_tmap; type_exports_tmap; export_kind })
 
-  and cjs_extract_named_exports cx reason local_module t =
-    elab_t cx t (Annot_CJSExtractNamedExportsT (reason, local_module))
+  and lazy_cjs_extract_named_exports cx reason local_module t =
+    lazy
+      (let concretize t =
+         match elab_t cx t (Annot_ConcretizeForCJSExtractNamedExports reason) with
+         | OpenT (_, id) -> get_fully_resolved_type cx id
+         | t -> t
+       in
+       CJSExtractNamedExportsTKit.on_type cx ~concretize (reason, local_module) t
+      )
 
   and import_typeof cx reason export_name t = elab_t cx t (Annot_ImportTypeofT (reason, export_name))
 

src/typing/debug_js.ml

@@ -675,7 +675,6 @@ and dump_use_t_ (depth, tvars) cx t =
         t
     | CallT { use_op; reason = _; call_action = ConcretizeCallee _; return_hint = _ } ->
       p ~extra:(spf "%s ConcretizeCallee" (string_of_use_op use_op)) t
-    | CJSExtractNamedExportsT _ -> p t
     | ConstructorT _ -> p t
     | CopyNamedExportsT _ -> p t
     | CopyTypeExportsT _ -> p t

src/typing/default_resolve.ml

@@ -144,7 +144,6 @@ let rec default_resolve_touts ~flow ?resolve_callee cx loc u =
   | HasOwnPropT _ -> ()
   | GetValuesT (_, t) -> resolve t
   | ElemT (_, _, _, action) -> resolve_elem_action action
-  | CJSExtractNamedExportsT (_, _, t)
   | CopyNamedExportsT (_, _, t)
   | CopyTypeExportsT (_, _, t) ->
     resolve t

src/typing/flow_common.ml

@@ -315,6 +315,9 @@ module type S = sig
   val possible_concrete_types_for_sentinel_prop_test :
     Context.t -> Reason.reason -> Type.t -> Type.t list
 
+  val singleton_concrete_type_for_cjs_extract_named_exports :
+    Context.t -> Reason.reason -> Type.t -> Type.t
+
   val singleton_concrete_type_for_inspection : Context.t -> Reason.reason -> Type.t -> Type.t
 
   val possible_concrete_types_for_computed_props :

src/typing/flow_js.ml

@@ -200,20 +200,11 @@ struct
                 { reason; name_loc; preferred_def_locs; export_name; target_module_t; tout }
             )
       )
-
-    let cjs_extract_named_exports cx (reason, local_module) proto_t =
-      Tvar.mk_where cx reason (fun t ->
-          FlowJs.rec_flow
-            cx
-            DepthTrace.dummy_trace
-            (proto_t, CJSExtractNamedExportsT (reason, local_module, t))
-      )
   end
 
   module CopyNamedExportsTKit = CopyNamedExportsT_kit (Import_export_helper)
   module CopyTypeExportsTKit = CopyTypeExportsT_kit (Import_export_helper)
   module ExportTypeTKit = ExportTypeT_kit (Import_export_helper)
-  module CJSExtractNamedExportsTKit = CJSExtractNamedExportsT_kit (Import_export_helper)
   include InstantiationKit
 
   (* get prop *)
@@ -719,8 +710,11 @@ struct
           CopyNamedExportsTKit.on_AnyT cx target_module t
         | (AnyT (_, _), CopyTypeExportsT (_, target_module, t)) ->
           CopyTypeExportsTKit.on_AnyT cx target_module t
-        | (_, CJSExtractNamedExportsT (reason, local_module, t_out)) ->
-          CJSExtractNamedExportsTKit.on_concrete_type cx (reason, local_module) l t_out
+        | ( t,
+            ConcretizeT
+              { reason = _; kind = ConcretizeForCJSExtractNamedExports; seen = _; collector }
+          ) ->
+          TypeCollector.add collector t
         (******************************)
         (* optional chaining - part A *)
         (******************************)
@@ -5896,7 +5890,6 @@ struct
     | BindT _
     | CallT _
     | CallElemT _
-    | CJSExtractNamedExportsT _
     | CondT _
     | ConstructorT _
     | CopyNamedExportsT _
@@ -9325,6 +9318,9 @@ struct
   and possible_concrete_types_for_inspection cx reason t =
     possible_concrete_types ConcretizeForInspection cx reason t
 
+  and singleton_concrete_type_for_cjs_extract_named_exports cx reason t =
+    singleton_concrete_type ConcretizeForCJSExtractNamedExports cx reason t
+
   and singleton_concrete_type_for_inspection cx reason t =
     singleton_concrete_type ConcretizeForInspection cx reason t
 

src/typing/flow_js.mli

@@ -91,6 +91,9 @@ val possible_concrete_types_for_inspection : Context.t -> Reason.reason -> Type.
 val possible_concrete_types_for_imports_exports :
   Context.t -> Reason.reason -> Type.t -> Type.t list
 
+val singleton_concrete_type_for_cjs_extract_named_exports :
+  Context.t -> Reason.reason -> Type.t -> Type.t
+
 val singleton_concrete_type_for_inspection : Context.t -> Reason.reason -> Type.t -> Type.t
 
 val possible_concrete_types_for_predicate :

src/typing/flow_js_utils.ml

@@ -1417,8 +1417,6 @@ module type Import_export_helper_sig = sig
     Type.t ->
     Type.t
 
-  val cjs_extract_named_exports : Context.t -> Reason.t * Type.moduletype -> Type.t -> Type.t
-
   val return : Context.t -> Type.t -> r
 end
 
@@ -2048,34 +2046,35 @@ module ExportTypeT_kit (F : Import_export_helper_sig) = struct
       F.return cx target_module_t
 end
 
-module CJSExtractNamedExportsT_kit (F : Import_export_helper_sig) = struct
-  let on_concrete_type cx (reason, local_module) = function
+module CJSExtractNamedExportsTKit = struct
+  let rec on_type cx ~concretize (reason, local_module) t =
+    match concretize t with
     | NamespaceT { namespace_symbol = _; values_type; types_tmap } ->
       (* Copy props from the values part *)
-      let module_t = F.cjs_extract_named_exports cx (reason, local_module) values_type in
+      let module_type = on_type cx ~concretize (reason, local_module) values_type in
       (* Copy type exports *)
-      F.export_named
+      ExportNamedTKit.mod_ModuleT
         cx
-        ( reason,
-          NameUtils.Map.empty,
+        ( NameUtils.Map.empty,
           Properties.extract_named_exports (Context.find_props cx types_tmap),
           DirectExport
         )
-        module_t
+        module_type;
+      module_type
     (* ObjT CommonJS export values have their properties turned into named exports. *)
     | DefT (_, ObjT o) ->
       let { props_tmap; proto_t; _ } = o in
       (* Copy props from the prototype *)
-      let module_t = F.cjs_extract_named_exports cx (reason, local_module) proto_t in
+      let module_type = on_type cx ~concretize (reason, local_module) proto_t in
       (* Copy own props *)
-      F.export_named
+      ExportNamedTKit.mod_ModuleT
         cx
-        ( reason,
-          Properties.extract_named_exports (Context.find_props cx props_tmap),
+        ( Properties.extract_named_exports (Context.find_props cx props_tmap),
           NameUtils.Map.empty,
           DirectExport
         )
-        module_t
+        module_type;
+      module_type
     (* InstanceT CommonJS export values have their properties turned into named exports. *)
     | DefT (_, InstanceT { inst = { own_props; proto_props; _ }; _ }) ->
       let extract_named_exports id =
@@ -2088,12 +2087,14 @@ module CJSExtractNamedExportsT_kit (F : Import_export_helper_sig) = struct
         cx
         (extract_named_exports own_props, NameUtils.Map.empty, DirectExport)
         local_module;
+
       (* Copy proto props *)
       (* TODO: own props should take precedence *)
-      F.export_named
+      ExportNamedTKit.mod_ModuleT
         cx
-        (reason, extract_named_exports proto_props, NameUtils.Map.empty, DirectExport)
-        (ModuleT local_module)
+        (extract_named_exports proto_props, NameUtils.Map.empty, DirectExport)
+        local_module;
+      local_module
     (* If the module is exporting any or Object, then we allow any named import. *)
     | AnyT _ ->
       let {
@@ -2104,19 +2105,15 @@ module CJSExtractNamedExportsT_kit (F : Import_export_helper_sig) = struct
       } =
         local_module
       in
-      let module_t =
-        ModuleT
-          {
-            module_reason;
-            module_export_types = { exporttypes with has_every_named_export = true };
-            module_is_strict;
-            module_available_platforms;
-          }
-      in
-      F.return cx module_t
+      {
+        module_reason;
+        module_export_types = { exporttypes with has_every_named_export = true };
+        module_is_strict;
+        module_available_platforms;
+      }
     (* All other CommonJS export value types do not get merged into the named
      * exports tmap in any special way. *)
-    | _ -> F.return cx (ModuleT local_module)
+    | _ -> local_module
 end
 
 (*******************)

src/typing/implicit_instantiation.ml

@@ -341,7 +341,6 @@ module Make (Observer : OBSERVER) (Flow : Flow_common.S) : S = struct
     | GetValuesT _
     | GetDictValuesT _
     (* Import-export related upper bounds won't appear during implicit instantiation. *)
-    | CJSExtractNamedExportsT _
     | CopyNamedExportsT _
     | CopyTypeExportsT _
     | ExportNamedT _

src/typing/module_info_analyzer.ml

@@ -465,22 +465,21 @@ let mk_module_t =
         has_every_named_export = false;
       }
     in
-    Tvar_resolver.mk_tvar_and_fully_resolve_where cx reason (fun t ->
-        Flow_js.flow
-          cx
-          ( export_t,
-            CJSExtractNamedExportsT
-              ( reason,
-                {
-                  module_reason = reason_exports_module;
-                  module_export_types;
-                  module_is_strict = Context.is_strict cx;
-                  module_available_platforms = Context.available_platforms cx;
-                },
-                t
-              )
-          )
-    )
+    ModuleT
+      (let concretize = Flow_js.singleton_concrete_type_for_cjs_extract_named_exports cx reason in
+       Flow_js_utils.CJSExtractNamedExportsTKit.on_type
+         cx
+         ~concretize
+         ( reason,
+           {
+             module_reason = reason_exports_module;
+             module_export_types;
+             module_is_strict = Context.is_strict cx;
+             module_available_platforms = Context.available_platforms cx;
+           }
+         )
+         export_t
+      )
   in
   let copy_star_exports cx reason exports module_t =
     let copy_named_exports module_t (loc, from_ns) =

src/typing/ty_normalizer.ml

@@ -540,7 +540,6 @@ module Make (I : INPUT) : S = struct
           uses_t_aux (t :: acc) rest
         | T.ReposLowerT { use_t = u; _ } :: rest -> uses_t_aux acc (u :: rest)
         (* skip these *)
-        | T.CJSExtractNamedExportsT _ :: rest -> uses_t_aux acc rest
         | u :: _ -> return (Ty.SomeUnknownUpper (T.string_of_use_ctor u))
       in
       (fun uses -> uses_t_aux [] uses)