# Pre-RFC: procmacros implemented in wasm **URL:** \ **Category:** compiler\ **Created:** [August 25, 2019, 6:18am UTC](https://internals.rust-lang.org/t/pre-rfc-procmacros-implemented-in-wasm/10860 "2019-08-25T06:18:46Z")\ **Posts on this page:** 1\ **Showing post:** 75
**Author:** ![pygy](https://sea2.discourse-cdn.com/flex002/user_avatar/internals.rust-lang.org/pygy/32/6041_2.png) [@pygy](https://internals.rust-lang.org/u/pygy)\ **Post date:** [September 3, 2019, 3:36pm UTC](https://internals.rust-lang.org/t/pre-rfc-procmacros-implemented-in-wasm/10860/75 "2019-09-03T15:36:36Z")
[Searching for "capability"](https://internals.rust-lang.org/search?q=capability) lead me to relevant threads, and ultimately to the Rust Secure Code Working Group. I'll review the various threads and other ongoing work, and I'll try to see if/what I can contribute. > [@Crate capability lists](https://internals.rust-lang.org/t/crate-capability-lists/8933/2): > > I’ve been thinking along similar lines, but specifically around the problem of restricting usage of unsafe. I posted some initial thoughts here: [https://groups.google.com/d/msg/cap-talk/t9al5hjN19U/XzHfR1peBAAJ](https://groups.google.com/d/msg/cap-talk/t9al5hjN19U/XzHfR1peBAAJ) I’ve thought about posting a “Pre-Pre-RFC” about this, but I guess I can start by spitballing here. Unsafe Features Synopsis: Extend the existing idea of cargo features with a special notion of “unsafe features” which can be used to whitelist usage of unsafe in dependencies (and their… > [@Build script capabilities](https://internals.rust-lang.org/t/build-script-capabilities/8635): > > (apologies if this has been discussed before, I couldn’t find anything) I touched on this problem in [[pre-pre-rfc?] Solving Crate Trust](https://internals.rust-lang.org/t/pre-pre-rfc-solving-crate-trust/6495), but it’s something worth splitting out. Currently, build scripts and compiler plugins (to a lesser degree) have unfettered power. They may end up doing whatever they want, and it’s hard to reason about them in the context of other build systems. There are a couple of things this impacts: Caching/artifact sharing: It’s hard to cache the results of crates com… > **[GitHub - rust-secure-code/wg: Coordination repository for the Secure Code...](https://github.com/rust-secure-code/wg)** > > Coordination repository for the Secure Code Working Group - GitHub - rust-secure-code/wg: Coordination repository for the Secure Code Working Group --- _[View the full topic](https://internals.rust-lang.org/t/pre-rfc-procmacros-implemented-in-wasm/10860)._