bjoernager/rust
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Implement #[rustc_default_body_unstable]

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This attribute allows to mark default body of a trait function as
unstable. This means that implementing the trait without implementing
the function will require enabling unstable feature.

This is useful in conjunction with `#[rustc_must_implement_one_of]`,
we may want to relax requirements for a trait, for example allowing
implementing either of `PartialEq::{eq, ne}`, but do so in a safe way
-- making implementation of only `PartialEq::ne` unstable.
This commit is contained in:
Maybe Waffle 2022-04-27 18:14:19 +04:00
parent 96b9bb4620
commit 177af47104
14 changed files with 206 additions and 17 deletions
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1
compiler/rustc_ast_passes/src/feature_gate.rs
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@ -417,6 +417,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
|| attr.has_name(sym::stable)
|| attr.has_name(sym::rustc_const_unstable)
|| attr.has_name(sym::rustc_const_stable)
|| attr.has_name(sym::rustc_default_body_unstable)
{
struct_span_err!(
self.sess,