RequirementSequence

The AST containing base.

The declaration of the trait defining the requirements in this sequence.

An index in the members of base.

An index in the variants of ast[base].members[member] if it’s a bundle.

Creates an instance listing the requirements of base, which is in ast.

Advances to the next requirement and returns it, or nil if no next requirement exists.

Advances to the next requirement variant in bundle and returns it, or nil if no next variant exists.