This is hand-wavy for sure, but I don't think Emitter.prototype.emit is called more than once per AST node, and the number of cases should be less than the numb

This is hand-wavy for sure, but I don't think Emitter.prototype.emit is called more than once per AST node, and the number of cases should be less than the number of calls to .emit, so there should be fewer cases than AST nodes (which is a statically knowable number).