In the interface Name symbol table, it is wasteful to repeat the (package,module) pair for every serialized name. Almost certainly we repeat the combination (my-pk, A.B) in many entries, because if we refer to one entity from A.B we probably refer to others. Using a deduplication table makes Modules shared both in the interface file and on the heap -- once we decode a Module from a deduplication table, we'll share it across all Names which use that module. Previously, we'd get a newly-allocated but duplicate Module per deserialized Name. Patch incoming