disallow rest spreading on packed modules

Author: tsnobip

compiler/frontend/ast_tuple_pattern_flatten.ml

@@ -64,7 +64,11 @@ let flattern_tuple_pattern_vb (self : Bs_ast_mapper.mapper)
           }
           :: acc)
     | _ -> {pvb_pat; pvb_expr; pvb_loc = vb.pvb_loc; pvb_attributes} :: acc)
-  | Ppat_record (lid_pats, _, _rest), Pexp_pack {pmod_desc = Pmod_ident id} ->
+  | Ppat_record (_, _, Some rest), Pexp_pack {pmod_desc = Pmod_ident _} ->
+    Location.raise_errorf ~loc:rest.ppat_loc
+      "Record rest patterns are not supported when destructuring modules. Bind \
+       the module fields explicitly."
+  | Ppat_record (lid_pats, _, None), Pexp_pack {pmod_desc = Pmod_ident id} ->
     Ext_list.map_append lid_pats acc (fun {lid; x = pat} ->
         match lid.txt with
         | Lident s ->

tests/build_tests/super_errors/expected/record_rest_module_destructure.res.expected

@@ -0,0 +1,10 @@
+
+  We've found a bug for you!
+  /.../fixtures/record_rest_module_destructure.res:3:15-34
+
+  1 │ module A = Belt.Array
+  2 │ 
+  3 │ let {push, ...arrayMethods as rest} = module(A)
+  4 │ 
+
+  Record rest patterns are not supported when destructuring modules. Bind the module fields explicitly.

tests/build_tests/super_errors/fixtures/record_rest_module_destructure.res

@@ -0,0 +1,3 @@
+module A = Belt.Array
+
+let {push, ...arrayMethods as rest} = module(A)