Auto merge of #113210 - fee1-dead-contrib:effects-mvp, r=oli-obk

Effects/keyword generics MVP

This adds `feature(effects)`, which adds `const host: bool` to the generics of const functions, const traits and const impls. This will be used to replace the current logic around const traits.

r? `@oli-obk`

1 files changed, 6 insertions, 0 deletions

diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index 3c5bff3812a..36600004404 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -723,6 +723,12 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         and it is only intended to be used in `alloc`."
     ),
 
+    rustc_attr!(
+        rustc_host, AttributeType::Normal, template!(Word), ErrorFollowing,
+        "#[rustc_host] annotates const generic parameters as the `host` effect param, \
+        and it is only intended for internal use and as a desugaring."
+    ),
+
     BuiltinAttribute {
         name: sym::rustc_diagnostic_item,
         // FIXME: This can be `true` once we always use `tcx.is_diagnostic_item`.