Module graph 

Structs

Graph

memory/root hold the whole-program subtype registry (grows with every distinct type seen — stdlib signatures included), and used to be deep-cloned on every Graph::clone() (in turn triggered by every Context::clone()). Arc-wrapping makes that clone O(1); mutators (add_type, cache_subtype) recover an owned value via Arc::unwrap_or_clone, which only actually copies when another live Arc still shares the allocation.

Node