Constant destinations

[wjmelements]

A number (decimal or hex) can be a valid label; however, at the end of assembly: validate that the number is equal to the actual JUMPDEST position.

[wjmelements]

I cannot think of a great reason to want such a feature. One reason I can think of is to assert that a JUMPDEST has a specific byte-width for its index in the code. But I don't remember why I thought this would be a good feature.

Invalid JUMPIs have been used to assert, draining the caller's gas. If we validate, we should have an option to skip such validation in case the invalidity is intentional.

[wjmelements]

I have thought of a reason for this feature.