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`

2 files changed, 8 insertions, 0 deletions

diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index 906c31c9a3d..5185820a727 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/compiler/rustc_feature/src/active.rs
@@ -391,6 +391,8 @@ declare_features! (
     (active, doc_masked, "1.21.0", Some(44027), None),
     /// Allows `dyn* Trait` objects.
     (incomplete, dyn_star, "1.65.0", Some(102425), None),
+    // Uses generic effect parameters for ~const bounds
+    (active, effects, "CURRENT_RUSTC_VERSION", Some(102090), None),
     /// Allows `X..Y` patterns.
     (active, exclusive_range_pattern, "1.11.0", Some(37854), None),
     /// Allows exhaustive pattern matching on types that contain uninhabited types.
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`.