diff --git a/doc/md/examples/grammar.txt b/doc/md/examples/grammar.txt
index d8d695f8bea..f4d3cd95f6c 100644
--- a/doc/md/examples/grammar.txt
+++ b/doc/md/examples/grammar.txt
@@ -214,7 +214,7 @@
     'break' <id> <exp_nullary>?
     'continue' <id>
     'debug' <exp_nest>
-    '(' <exp_post>? 'with' <list(<exp_field>, ';')> ')' <exp_nest>
+    '(' <exp_post>? 'with' <list(<exp_field>, ',')> ')' <exp_nest>
     'if' <exp_nullary> <exp_nest>
     'if' <exp_nullary> <exp_nest> 'else' <exp_nest>
     'try' <exp_nest> <catch>
diff --git a/src/mo_frontend/parser.mly b/src/mo_frontend/parser.mly
index 1853ff5d23d..c55a82c9514 100644
--- a/src/mo_frontend/parser.mly
+++ b/src/mo_frontend/parser.mly
@@ -703,7 +703,7 @@ exp_un(B) :
       BreakE(x', TupE([]) @? no_region) @? at $sloc }
   | DEBUG e=exp_nest
     { DebugE(e) @? at $sloc }
-  | LPAR base=exp_post(ob)? WITH fs=seplist(exp_field, semicolon) RPAR e=exp_nest (* parentheticals to qualify message sends *)
+  | LPAR base=exp_post(ob)? WITH fs=seplist(exp_field, COMMA) RPAR e=exp_nest (* parentheticals to qualify message sends *)
     { match e.it with
       | CallE (base0_opt, f, is, args) ->
         { e with it = CallE (Some (ObjE (Option.(to_list base0_opt @ to_list base), fs) @? e.at), f, is, args) }
diff --git a/src/mo_frontend/printers.ml b/src/mo_frontend/printers.ml
index 7105e3e7cc7..f62f6617d4e 100644
--- a/src/mo_frontend/printers.ml
+++ b/src/mo_frontend/printers.ml
@@ -167,6 +167,7 @@ let string_of_symbol = function
   | X (N N_exp_plain) -> "<exp_plain>"
   | X (N N_exp_post_bl_) -> "<exp_post(bl)>"
   | X (N N_exp_post_ob_) -> "<exp_post(ob)>"
+  | X (N N_option_exp_post_ob__) -> "<exp_post(ob)>?"
   | X (N N_exp_un_bl_) -> "<exp_un(bl)>"
   | X (N N_exp_un_ob_) -> "<exp_un(ob)>"
   | X (N N_func_body) -> "<func_body>"
@@ -199,6 +200,7 @@ let string_of_symbol = function
   | X (N N_seplist_dec_field_semicolon_) -> "seplist(<dec_field>,<semicolon>)"
   | X (N N_seplist_exp_ob__COMMA_) -> "seplist(<exp(ob)>,,)"
   | X (N N_seplist_exp_field_semicolon_) -> "seplist(<exp_field>,<semicolon>)"
+  | X (N N_seplist_exp_field_COMMA_) -> "seplist(<exp_field>,,)"
   | X (N N_seplist1_exp_field_semicolon_) -> "seplist1(<exp_field>,<semicolon>)"
   | X (N N_separated_nonempty_list_AND_exp_post_ob__) -> "seplist+(<exp_post(ob)>,and)"
   | X (N N_seplist_exp_nonvar_ob__COMMA_) -> "seplist(<exp_nonvar(ob)>,,)"
diff --git a/test/fail/ok/syntax5.tc.ok b/test/fail/ok/syntax5.tc.ok
index a882586ced3..727c77d6936 100644
--- a/test/fail/ok/syntax5.tc.ok
+++ b/test/fail/ok/syntax5.tc.ok
@@ -18,3 +18,4 @@ syntax5.mo:3.1: syntax error [M0001], unexpected end of input, expected one of t
   <unop> <exp_bin(ob)>
   <inst> <exp_nullary(ob)>
   [ <exp(ob)> ]
+  with seplist(<exp_field>,,) ) <exp_nest>
diff --git a/test/run-drun/par.mo b/test/run-drun/par.mo
index 6338980062b..4b0425d0940 100644
--- a/test/run-drun/par.mo
+++ b/test/run-drun/par.mo
@@ -49,7 +49,7 @@ actor A {
         assert 3 == (await (with cycles = 101) closA());
         assert 3 == (await (with cycles = 102) closB());
 
-        await (with yeah = 8; timeout = 55; cycles = 1000)
+        await (with yeah = 8, timeout = 55, cycles = 1000)
         foo(func() : async () = async { assert message == "Hi!" });
         await (with cycles = 5000)
         bar(func() : async () = async { assert message == "Hi!" });