Target Feature: target_feature 1.1

Centril / rfc-effects

Preparing an RFC on effect polymorphism in Rust with focus on 'const'

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Target Feature: target_feature 1.1 #10

Open Centril opened 6 years ago

Centril commented 6 years ago

RFC: https://github.com/rust-lang/rfcs/pull/2396
Old RFC: https://github.com/rust-lang/rfcs/pull/2212
RFC 2045: https://github.com/rust-lang/rfcs/pull/2045

gnzlbg commented 6 years ago

One major problem with #[target_feature] as proposed is that it cannot propagate effects properly. This makes it impossible for libraries to work around code-generation issues: https://github.com/rust-lang-nursery/stdsimd/issues/362#issuecomment-380419065

An effect systems for target features would need to allow a caller to enable target features for their callees. This might mean that all Rust functions my need to be always polymorphic with respect to target-feature effects.