The built-in WebAssembly GC could just be the native JS GC, which is very, very good for most dynamic languages. There&#x27;s really not that much difference between GCing JS, Lua, Python, and MyDynamicLanguageWithRubySyntaxAndLuaSemanticsAndNewFeatureX. I don&#x27;t see why they&#x27;d need to do anything other than just expose the GC that&#x27;s already there. Browser makers are smart enough to know &quot;invent new GC that solves every conceivable language&#x27;s memory problems&quot; isn&#x27;t going to work.<p>Since WebAsm is still Functional languages would still have the freedom to implement their own more efficient GC (avoid the write barrier in a lot of cases, scan only the young heap most of the time, etc).