I see a fellow enjoyer of bugs ;)
>vmap afaict only exposes push-back and pop-front for mutation
what about https://doc.rust-lang.org/nightly/std/io/trait.Write.html#ty... ?
>and critical methods aren't inlined
aren't inlined explicitly. This does not mean that they are not inlined in practice (depending on build options). Also, LLVM can look inside a noinline available method body for alias analysis :(
This is a big pain whenever one wants to do formally-UB shennenigans. I'm not a rustacean, but in julia a @noinline directive will simply tell LLVM not to inline, but won't hide the method body from LLVM's alias analysis. For that, one needs to do something similar to dynamic linking, with the implied performance impact (the equivalent of non-LTO static linking doesn't exist in julia).