Fix issues with the arity of externals.

Fixes #6880

Author: cristianoc

CHANGELOG.md

@@ -20,7 +20,7 @@
 - Allow free vars in types for type coercion `e :> t`. https://github.com/rescript-lang/rescript-compiler/pull/6828
 - Allow `private` in with constraints. https://github.com/rescript-lang/rescript-compiler/pull/6843
 - Add regex literals as syntax sugar for `@bs.re`. https://github.com/rescript-lang/rescript-compiler/pull/6776
-- Improved mechanism to determine arity of externals, which is consistent however the type is written. https://github.com/rescript-lang/rescript-compiler/pull/6874
+- Improved mechanism to determine arity of externals, which is consistent however the type is written. https://github.com/rescript-lang/rescript-compiler/pull/6874 https://github.com/rescript-lang/rescript-compiler/pull/6881
 
 #### :boom: Breaking Change
 

jscomp/core/lam_compile_external_call.ml

@@ -365,7 +365,9 @@ let translate_ffi (cxt : Lam_compile_context.t) arg_types
          2. support [@@scope "window"]
          we need know whether we should call [add_js_module] or not
       *)
-      translate_scoped_module_val external_module_name name scopes ~dynamic_import
+      let e = translate_scoped_module_val external_module_name name scopes ~dynamic_import in
+      if args = [] then e
+      else E.call ~info:{ arity = Full; call_info = Call_na } e args
   | Js_module_as_class module_name ->
       let fn = external_var module_name ~dynamic_import in
       let args, eff = assemble_args_no_splice arg_types args in

jscomp/frontend/external_ffi_types.ml

@@ -240,7 +240,13 @@ let from_string s : t =
 
 let () =
   Primitive.coerce :=
-    fun ({prim_name; prim_arity; prim_native_name; prim_alloc = _} :
+    fun ({
+           prim_name;
+           prim_arity;
+           prim_native_name;
+           prim_alloc = _;
+           prim_from_constructor = _;
+         } :
           Primitive.description) (p2 : Primitive.description) ->
       let p2_native = p2.prim_native_name in
       prim_name = p2.prim_name && prim_arity = p2.prim_arity

jscomp/gentype_tests/typescript-react-example/src/ImportHookDefault.res.js

@@ -25,6 +25,7 @@ type description =
     prim_arity: int;           (* Number of arguments *)
     prim_alloc: bool;          (* Does it allocates or raise? *)
     prim_native_name: string;  (* Name of C function for the nat. code gen. *)
+    prim_from_constructor: bool; (* Is it from a type constructor instead of a concrete function type? *)
   }
 
 let coerce : (description -> description -> bool) ref = 
@@ -37,15 +38,17 @@ let simple ~name ~arity ~alloc =
   {prim_name = name;
    prim_arity = arity;
    prim_alloc = alloc;
-   prim_native_name = "";}
+   prim_native_name = "";
+   prim_from_constructor = false;}
 
 let make ~name ~alloc ~native_name ~arity =
   {prim_name = name;
    prim_arity = arity;
    prim_alloc = alloc;
-   prim_native_name = native_name;}
+   prim_native_name = native_name;
+   prim_from_constructor = false;}
 
-let parse_declaration valdecl ~arity =
+let parse_declaration valdecl ~arity ~from_constructor =
   let name, native_name =
     match valdecl.pval_prim with
     | name :: name2 :: _ -> (name, name2)
@@ -56,7 +59,8 @@ let parse_declaration valdecl ~arity =
   {prim_name = name;
    prim_arity = arity;
    prim_alloc = true;
-   prim_native_name = native_name;}
+   prim_native_name = native_name;
+   prim_from_constructor = from_constructor}
 
 open Outcometree
 

jscomp/gentype_tests/typescript-react-example/src/ImportHooks.res.js

@@ -22,6 +22,7 @@ type description = private
     prim_arity: int;           (* Number of arguments *)
     prim_alloc: bool;          (* Does it allocates or raise? *)
     prim_native_name: string;  (* Name of C function for the nat. code gen. *)
+    prim_from_constructor: bool; (* Is it from a type constructor instead of a concrete function type? *)
   }
 
 (* Invariant [List.length d.prim_native_repr_args = d.prim_arity] *)
@@ -42,6 +43,7 @@ val make
 val parse_declaration
   :  Parsetree.value_description
   -> arity: int
+  -> from_constructor: bool
   -> description
 
 val print