# Description
Follow-up of #8940. As @bobhy pointed out, it makes sense for the
behaviour of flags to match the one for positional arguments, where
default values are of type `Option<Value>` instead of
`Option<Expression>`.
# User-Facing Changes
The same ones from the original PR:
- Flag default values will now be parsed as constants.
- If the default value is not a constant, a parser error is displayed.
# Tests + Formatting
A [new
test](e34e2d35f4/src/tests/test_engine.rs (L338-L344))
has been added to verify the new restriction.
d9a00a876b