record_type_zero_fields_but_trailing_comma

A record type without fields can't have a trailing comma.

The analyzer produces this diagnostic when a record type that has no fields has a trailing comma. Empty record types can't contain a comma.

The following code produces this diagnostic because the empty record type has a trailing comma:

void f((,) r) {}

If the record type is intended to be empty, then remove the comma:

void f(() r) {}

If the record type is intended to have one or more fields, then add the types of those fields:

void f((int, int) r) {}