Support type definition of empty record.

Author: cristianoc

CHANGELOG.md

@@ -18,7 +18,7 @@
 
   - :boom: when V4 is activated, at most one component is allowed for each module.
 
-- Add support for empty record literal `{}` for records with only optional fields https://github.com/rescript-lang/syntax/pull/632
+- Add support for empty record literal `{}` for records with only optional fields, and type definition of empty record (e.g. `type empty = {}`)  https://github.com/rescript-lang/syntax/pull/632
 
 #### :bug: Bug Fix
 

src/res_core.ml

@@ -4909,13 +4909,6 @@ and parseRecordOrObjectDecl p =
           :: parseCommaDelimitedRegion ~grammar:Grammar.FieldDeclarations
                ~closing:Rbrace ~f:parseFieldDeclarationRegion p
       in
-      let () =
-        match fields with
-        | [] ->
-          Parser.err ~startPos p
-            (Diagnostics.message "A record needs at least one field")
-        | _ -> ()
-      in
       Parser.expect Rbrace p;
       Parser.eatBreadcrumb p;
       (None, Asttypes.Public, Parsetree.Ptype_record fields))

tests/parsing/errors/typeDef/expected/emptyRecord.res.txt

@@ -1,11 +1,2 @@
-
-  Syntax error!
-  tests/parsing/errors/typeDef/emptyRecord.res:1:15-16
-
-  1 │ type record = {}
-  2 │ 
-
-  A record needs at least one field
-
 type nonrec record = {
   }