add default to enum switches

[TechnikTil]

This PR adds a default to all Expr switches, so that libraries that try to add an extra enum entry with macros don't run into errors.

[Simn]

I don't agree with this. The whole purpose of exhaustiveness checks in pattern matching is to ensure that all cases are handled. We lose that functionality by adding a default case everywhere.

[TechnikTil]

I don't agree with this. The whole purpose of exhaustiveness checks in pattern matching is to ensure that all cases are handled. We lose that functionality by adding a default case everywhere.

Fair
would a throw be better?

[Kriptel]

I think that for correct work it is necessary to add compilation conditions.

example:

#if extra_exprs
default:
#end

[TechnikTil]

I think that for correct work it is necessary to add compilation conditions.

example:

#if extra_exprs
default:
#end

sure, let me do that