Typed JSX intrinsics

Summary:
This adds support to Flow for [userland-pluggable] typed JSX intrinsics.

Out of the box, any intrinsic is typed as `any` (just as all intrinsics are currently typed today). This is important because different apps have different intrinsics (i.e. ReactDOM has things like div/span/table/etc, but ReactNative should have no such intrinsics -- and perhaps may one day have its own set).

The design is fairly straightforward: A user includes a libdef that defines a global `$JSXIntrinsics` object type whose keys represent the names of built-ins and whose value-types represent the type of the ReactComponent for the intrinsic. Hopefully the tests do a good job of showing this in action.

TypeScript did a pretty good job with their design, so this is inspired heavily by that.

Reviewed By: bhosmer

Differential Revision: D2714159

fb-gh-sync-id: c7823fb4e4497e3799f633b831b83cd9b3cfd7d0

lib/core.js

@@ -608,3 +608,6 @@ declare var exports: any;
 
 /* Commonly available, shared between node and dom */
 declare var console: any;
+
+/* JSX Intrinsics */
+type $JSXIntrinsics = Object;

src/common/flowConfig.ml

@@ -45,6 +45,7 @@ module Opts = struct
     esproposal_class_instance_fields: esproposal_feature_mode;
     esproposal_class_static_fields: esproposal_feature_mode;
     esproposal_decorators: esproposal_feature_mode;
+    facebook_ignore_fbt: bool;
     ignore_non_literal_requires: bool;
     moduleSystem: moduleSystem;
     module_name_mappers: (Str.regexp * string) list;
@@ -111,6 +112,7 @@ module Opts = struct
     esproposal_class_instance_fields = ESPROPOSAL_WARN;
     esproposal_class_static_fields = ESPROPOSAL_WARN;
     esproposal_decorators = ESPROPOSAL_WARN;
+    facebook_ignore_fbt = false;
     ignore_non_literal_requires = false;
     moduleSystem = Node;
     module_name_mappers = [];
@@ -490,54 +492,64 @@ let parse_excludes config lines =
 
 let file_extension = Str.regexp "^\\(\\.[^ \t]+\\)+$"
 
-let parse_options config lines = Opts.(
-  let options = Opts.parse config.options lines
-    |> Opts.define_opt "esproposal.class_instance_fields" Opts.({
+let parse_options config lines =
+  let open Opts in
+  let options = parse config.options lines
+    |> define_opt "esproposal.class_instance_fields" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_esproposal_feature_flag ~allow_enable:true;
       setter = (fun opts v -> {
         opts with esproposal_class_instance_fields = v;
       });
-    })
+    }
 
-    |> Opts.define_opt "esproposal.class_static_fields" Opts.({
+    |> define_opt "esproposal.class_static_fields" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_esproposal_feature_flag ~allow_enable:true;
       setter = (fun opts v -> {
         opts with esproposal_class_static_fields = v;
       });
-    })
+    }
 
-    |> Opts.define_opt "esproposal.decorators" Opts.({
+    |> define_opt "esproposal.decorators" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_esproposal_feature_flag;
       setter = (fun opts v -> {
         opts with esproposal_decorators = v;
       });
-    })
+    }
 
-    |> Opts.define_opt "log.file" Opts.({
+    |> define_opt "facebook.ignore_fbt" {
+      _initializer = USE_DEFAULT;
+      flags = [];
+      optparser = optparse_boolean;
+      setter = (fun opts v -> {
+        opts with facebook_ignore_fbt = v;
+      });
+    }
+
+    |> define_opt "log.file" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_filepath;
       setter = (fun opts v -> {
         opts with log_file = Some v;
       });
-    })
+    }
 
-    |> Opts.define_opt "module.ignore_non_literal_requires" Opts.({
+    |> define_opt "module.ignore_non_literal_requires" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_boolean;
       setter = (fun opts v ->
         {opts with ignore_non_literal_requires = v;}
       );
-    })
+    }
 
-    |> Opts.define_opt "module.file_ext" Opts.({
+    |> define_opt "module.file_ext" {
       _initializer = INIT_FN (fun opts -> {
         opts with module_file_exts = SSet.empty;
       });
@@ -555,9 +567,9 @@ let parse_options config lines = Opts.(
         let module_file_exts = SSet.add v opts.module_file_exts in
         {opts with module_file_exts;}
       );
-    })
+    }
 
-    |> Opts.define_opt "module.name_mapper" Opts.({
+    |> define_opt "module.name_mapper" {
       _initializer = USE_DEFAULT;
       flags = [ALLOW_DUPLICATE];
       optparser = (fun str ->
@@ -580,9 +592,9 @@ let parse_options config lines = Opts.(
         let module_name_mappers = v :: opts.module_name_mappers in
         {opts with module_name_mappers;}
       );
-    })
+    }
 
-    |> Opts.define_opt "module.system" Opts.({
+    |> define_opt "module.system" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_enum [
@@ -592,9 +604,9 @@ let parse_options config lines = Opts.(
       setter = (fun opts v -> {
         opts with moduleSystem = v;
       });
-    })
+    }
 
-    |> Opts.define_opt "module.system.node.resolve_dirname" Opts.({
+    |> define_opt "module.system.node.resolve_dirname" {
       _initializer = INIT_FN (fun opts -> {
         opts with node_resolver_dirnames = [];
       });
@@ -604,84 +616,83 @@ let parse_options config lines = Opts.(
         let node_resolver_dirnames = v :: opts.node_resolver_dirnames in
         {opts with node_resolver_dirnames;}
       );
-    })
+    }
 
-    |> Opts.define_opt "munge_underscores" Opts.({
+    |> define_opt "munge_underscores" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_boolean;
       setter = (fun opts v ->
         {opts with munge_underscores = v;}
       );
-    })
+    }
 
-    |> Opts.define_opt "server.max_workers" Opts.({
+    |> define_opt "server.max_workers" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_uint;
       setter = (fun opts v ->
         {opts with max_workers = v;}
       );
-    })
+    }
 
-    |> Opts.define_opt "strip_root" Opts.({
+    |> define_opt "strip_root" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_boolean;
       setter = (fun opts v ->
         {opts with strip_root = v;}
       );
-    })
+    }
 
-    |> Opts.define_opt "suppress_comment" Opts.({
+    |> define_opt "suppress_comment" {
       _initializer = USE_DEFAULT;
       flags = [ALLOW_DUPLICATE];
       optparser = optparse_regexp;
       setter = (fun opts v -> {
         opts with suppress_comments = v::(opts.suppress_comments);
       });
-    })
+    }
 
-    |> Opts.define_opt "suppress_type" Opts.({
+    |> define_opt "suppress_type" {
       _initializer = USE_DEFAULT;
       flags = [ALLOW_DUPLICATE];
       optparser = optparse_string;
       setter = (fun opts v -> {
         opts with suppress_types = SSet.add v opts.suppress_types;
       });
-    })
+    }
 
-    |> Opts.define_opt "temp_dir" Opts.({
+    |> define_opt "temp_dir" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_filepath;
       setter = (fun opts v -> {
         opts with temp_dir = v;
       });
-    })
+    }
 
-    |> Opts.define_opt "traces" Opts.({
+    |> define_opt "traces" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_uint;
       setter = (fun opts v ->
         {opts with traces = v;}
       );
-    })
+    }
 
-    |> Opts.define_opt "unsafe.enable_getters_and_setters" Opts.({
+    |> define_opt "unsafe.enable_getters_and_setters" {
       _initializer = USE_DEFAULT;
       flags = [];
       optparser = optparse_boolean;
       setter = (fun opts v ->
         {opts with enable_unsafe_getters_and_setters = v;}
       );
-    })
+    }
 
     |> get_defined_opts
   in
   {config with options}
-)
 
 let assert_version (ln, line) =
   try

src/common/flowConfig.mli

@@ -19,6 +19,7 @@ module Opts : sig
     esproposal_class_instance_fields: esproposal_feature_mode;
     esproposal_class_static_fields: esproposal_feature_mode;
     esproposal_decorators: esproposal_feature_mode;
+    facebook_ignore_fbt: bool;
     ignore_non_literal_requires: bool;
     moduleSystem: moduleSystem;
     module_name_mappers: (Str.regexp * string) list;

src/typing/debug_js.ml

@@ -340,6 +340,10 @@ and _json_of_use_t_impl json_cx t = Hh_json.(
       "type", _json_of_t json_cx t
     ]
 
+  | ReifyTypeT (_, t_out) -> [
+      "t_out", _json_of_t json_cx t_out
+    ]
+
   | SpecializeT (_, cache, targs, tvar) -> [
       "cache", JSON_Bool cache;
       "types", JSON_Array (List.map (_json_of_t json_cx) targs);
@@ -454,6 +458,7 @@ and _json_of_use_t_impl json_cx t = Hh_json.(
       "target_module_t", _json_of_t json_cx target_module_t;
       "t_out", _json_of_t json_cx t_out;
     ]
+  | DebugPrintT _reason -> []
   )
 )
 
@@ -743,9 +748,16 @@ let json_of_t ?(depth=1000) cx t =
   let json_cx = { cx; depth; stack = ISet.empty; } in
   _json_of_t json_cx t
 
+let json_of_use_t ?(depth=1000) cx use_t =
+  let json_cx = { cx; depth; stack = ISet.empty; } in
+  _json_of_use_t json_cx use_t
+
 let jstr_of_t ?(depth=1000) cx t =
   Hh_json.json_to_multiline (json_of_t ~depth cx t)
 
+let jstr_of_use_t ?(depth=1000) cx use_t =
+  Hh_json.json_to_multiline (json_of_use_t ~depth cx use_t)
+
 let json_of_graph ?(depth=1000) cx = Hh_json.(
   let entries = IMap.fold (fun id _ entries ->
     let json_cx = { cx; depth; stack = ISet.empty; } in

src/typing/debug_js.mli

@@ -10,6 +10,8 @@
 
 val json_of_t: ?depth:int -> Context.t -> Type.t -> Hh_json.json
 val jstr_of_t: ?depth:int -> Context.t -> Type.t -> string
+val json_of_use_t: ?depth:int -> Context.t -> Type.use_t -> Hh_json.json
+val jstr_of_use_t: ?depth:int -> Context.t -> Type.use_t -> string
 val json_of_graph: ?depth:int -> Context.t -> Hh_json.json
 val jstr_of_graph: ?depth:int -> Context.t -> string
 val json_of_scope: ?depth:int -> Context.t -> Scope.t -> Hh_json.json

src/typing/flow_js.ml

@@ -1114,6 +1114,14 @@ let rec __flow cx ((l: Type.t), (u: Type.use_t)) trace =
     | l, UseT DestructuringT (reason, t, s) ->
       rec_flow_t cx trace (l, eval_selector cx reason t s)
 
+    (*************)
+    (* Debugging *)
+    (*************)
+
+    | (_, DebugPrintT (reason)) ->
+      let msg = (spf "!!! DebugPrintT: %s" (Debug_js.jstr_of_t cx l)) in
+      add_error cx [reason, msg];
+
     (************)
     (* tainting *)
     (************)
@@ -2393,6 +2401,20 @@ let rec __flow cx ((l: Type.t), (u: Type.use_t)) trace =
     | (TypeT(_,l), UseT TypeT(_,u)) ->
       rec_unify cx trace l u
 
+    | (TypeT(type_reason, l), GetPropT(get_reason, (prop_reason, name), t_out)) ->
+      (**
+       * Reify the type, extract the prop from that, then wrap that result in a
+       * TypeT again.
+       *)
+      let prop_t = mk_tvar_where cx get_reason (fun t ->
+        rec_flow cx trace (l, GetPropT(get_reason, (prop_reason, name), t))
+      ) in
+      rec_flow cx trace (TypeT (type_reason, mk_typeof_annotation cx ~trace prop_t), T t_out)
+
+    | (TypeT(_, l), ReifyTypeT(_, t_out)) ->
+      (* Extract the type denoted by the type expression *)
+      rec_flow cx trace (l, T t_out)
+
     (* non-class/function values used in annotations are errors *)
     | _, UseT TypeT _ ->
       prerr_flow cx trace
@@ -3563,6 +3585,7 @@ and err_operation = function
   | HasOwnPropT _ -> "Property not found in"
   | HasPropT _ -> "Property not found in"
   | UnaryMinusT _ -> "Expected number instead of"
+  | ReifyTypeT _ -> "Internal Error: Invalid type applied to ReifyTypeT!"
   (* unreachable or unclassified use-types. until we have a mechanical way
      to verify that all legit use types are listed above, we can't afford
      to throw on a use type, so mark the error instead *)

src/typing/gc_js.ml

@@ -287,6 +287,9 @@ and gc_use cx state = function
   | NotT (_, t) ->
       gc cx state t
 
+  | ReifyTypeT (_, t_out) ->
+      gc cx state t_out
+
   | SpecializeT (_, _, ts, t) ->
       ts |> List.iter (gc cx state);
       gc cx state t
@@ -373,6 +376,8 @@ and gc_use cx state = function
       gc cx state target_module;
       gc cx state t_out;
 
+  | DebugPrintT _ -> ()
+
 and gc_id cx state id =
   let root_id, constraints = Flow_js.find_constraints cx id in (
     if state#mark id then (