This was not as bad as I thought it would be. Notes: 1) We need to use .get() for |remove|, since it is present on both bases of WeakCache<HashSet>. We could also punch through the one we want, but I thought this was clearer. 2) ::Ptr is private in GCHashSet. I think this is in error, but it's better to just use auto here anyway. It's a bit odd that this works, but I guess it's an artifact of the fact that the using decl is private but the underlying type is public. 3) I did not touch fixupNewTableAfterMovingGC, which is different from |sweep| as it seems to frob a bunch of internals that sweep doesn't care about. I guess if we want to automate this too we'll need to expose it via GCPolicy.

Comment on attachment 8742450 [details] [diff] [review] WeakCache_ObjectGroupCompartment_NewTable-v0.diff Review of attachment 8742450 [details] [diff] [review]: ----------------------------------------------------------------- Ptr is public in HashSet so I think this should be public in GCHashSet too. But this looks just fine with auto anyway.

https://hg.mozilla.org/integration/mozilla-inbound/rev/ddd7892d4ed6c18b9bbc1a6e25803b5e628452a7 Bug 1265483 - Use WeakCache to automate sweeping of ObjectGroupCompartment::NewTable; r=jonco